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Charcoal production for carbon sequestration Gustan Pari Djeni Hendra Dadang Setiawan Mahpudin Saepuloh Salim Soleh Mad Ali (Forest Products Technology Research and Development Center) Kiyoshi Miyakuni Nobuo Ishibashi (Japan International Cooperation Agency) April, 2004 Demonstration Study on Carbon Fixing Forest Management in Indonesia
Transcript

Charcoal production for

carbon sequestration

Gustan Pari Djeni Hendra

Dadang Setiawan Mahpudin Saepuloh

Salim Soleh Mad Ali

(Forest Products Technology Research and Development Center)

Kiyoshi Miyakuni Nobuo Ishibashi

(Japan International Cooperation Agency)

April, 2004

Demonstration Study on Carbon Fixing Forest Management in Indonesia

2

Table of contents

I. Background …………………………………………………………..……….. 4

II. Purposes and methodologies ……………………………………………. 6 1. Purposes 2. Sites for field trials 3. Comparison of carbonization efficiency: carbon yield 4. Comparison of cost efficiency 5. Estimation of carbon fixation potential by charcoal production

III. Types of kilns for field trials …………………………………………… 12 1. Nonpermanent kiln

1-a. Earth pit kiln 1-b. Modified earth pit kiln: Brick floor and galvanized iron sheet for closing

kiln 1-c. Sawdust mound kiln

2. Movable kiln 2-a. Single drum kiln: Air inlets at the side of drum 2-b. Single drum kiln: Air inlets at the bottom of drum 2-c. Double drum kiln

3. Permanent kiln: Yoshimura kiln 4. Kiln for producing sawdust charcoal: flat kiln

IV. Comparison of carbonization efficiency …………..………………… 32 1. Nonpermanent kilns 2. Movable kilns: drum kilns 3. Permanent kiln: Yoshimura kiln 4. Flat kiln for sawdust charcoal 5. Comparison of carbon yield

V. Comparison of cost efficiency …………..……………………..………… 44 1. Earth pit kiln and brick floor kiln 2. Earth pit kiln at sawmill 3. Drum kiln 4. Yoshimura kiln 5. Flat kiln 6. Comparison of costs for producing charcoal and carbon

3

VI. Evaluation of viability of charcoal production for CDM projects …………..………………… 56

1. Carbonization of wood material from shrubs or secondary forests 1-a. Total amount of charcoal and carbon produced in West Java experimental

sties 1-b. Carbonizing wood material from shrubs or secondary forests

2. Wood residues from plantation forests (Acacia mangium) 3. Wood residue from sawmill

VII. Conclusions ……………………………………………..………..……….. 67 1. Factors which affect on carbon yield and cost efficiency 2. Viable project types for carbon sequestration

Acknowledgements ……………………………………………………..…….... 68

References ………………………………………………………………..…….... 69

4

I. Background

In Indonesia, Logging operations in man-made and natural forests, wood industries (plywood factories, sawmills, pulp mills, etc.) and other activities are generating various types of wood residues and large amount of such residues are left unused. Recycling them has been an important issue.

According to the data provided in Okimori, et al., (2003), from Acacia mangium plantations in South Sumatra, 23.39% of total aboveground biomass becomes wood residue (56.4t/ha from 241.1t/ha) after taking out materials for pulp. As shown in Photo 1 and 2, those residues are abandoned in the field. It will decompose and can be the source of CO2 emission. At pulp mills, although wood bark is utilized as fuel for a generator, large amount is still abandoned (Okimori, et al., 2003).

Photo 1 and 2 Wood residue left in the plantation site (in PT. Musi Hutan Persada, South Sumatra)

Slabs from sawmills and plywood factories are often burned or thrown out to the river and sea (Ohara, et al., 1996a and Ohara, et al., 1996b). It is said that 20 to 30 percent of wood material becomes sawdust in sawmill operations (Kikata and Sri Nugroho, 1994). Often it is piled up beside the sawmill and burned (Photo 3). It can also cause water pollution if the sawdust hill is located beside a river.

If the sawdust is left decomposed or burned, it causes carbon emission. Therefore, it is necessary to develop ways to utilize sawdust and reduce pollution and carbon dioxide emission.

There are several ways to utilize sawdust. For example,

(1) Production of compost for agriculture (2) Mushroom cultivation (3) Material for activated charcoal (produced using a flat kiln) (4) Briquette charcoal (5) Material for mesquite coils

1 2

5

(6) Fuel for cooking (in Central and East Java)

Photo 3 Sawdust-hill beside sawmill (Bogor District, West Java) Unused sawdust is often burned at the sawmill.

Although the above methods have already been implemented in Indonesia, there is

still a large amount of sawdust un-utilized because of a limited market, location of sawmills (small scale sawmills are scattered in the whole Indonesia), the difficulty in controlling the quality of products, and so on. Producing compost can be a good way to return nutrients in wood residue to the soil. This method, however, is still not common because fermentation of sawdust is difficult.

One of the countermeasures for recycling those residues is production of charcoal for fuel, soil conditioner, water purification and other purposes, and at the same time, contributing to carbon sequestration or CO2 emission reductions (Seifritz, 1993; Ogawa, 1997; Kurosu and Sugiura, 1997, Glazer et al., 2002; Okimori et al., 2003).

Charcoal is a very stable substance (Seifritz, 1993: Glazer et al., 2002 and Ogawa, 2003). According to the experiments by Ogawa (2003), half-life of charcoal (carbonized in 1000 degree Celsius) was 1,029 years (if exposed to ozone: 0.005ppm). Charcoal carbonized under lower temperature was more stable under the higher concentration of ozone in the air. Charcoal can hold pure carbon inside it for a long time and playing a role as a carbon sink.

The efficiency for carbonization, however, must be examined. In the carbonization process (pyrolysis), considerable amount of carbon in wood material is gone to the air. The CO2 emission from charcoal production must be reduced. The cost efficiency also must be considered for the implementation of carbon fixing project by charcoal production.

6

II. Purposes and methodologies 1. Purposes

This report is to compare several types of kilns and find out effective charcoal

production methods for CDM projects, and evaluate viability of charcoal production for carbon sequestration.

(1) Comparison of efficiency among several types of charcoal production method

i. Efficiency for carbonization (carbon yield): The amount of CO2 emitted in the process of carbonization must be decreased.

ii. Cost efficiency: costs for producing 1 ton charcoal or carbon: Not only the costs for producing charcoal, but also for carbon should be analyzed.

(2) Estimation of potential for carbon fixation potential by charcoal production: How much carbon can be stored in charcoal? The amount of wood residue must be estimated.

Is must be mentioned that charcoal production is not admitted as CDM project at

present. This report is only for demonstrating the viability and efficiency of charcoal production for carbon sequestration. 2. Sites for field trials

(1) West Java: See Fig.1 for the map a. Forest Product Research and Development Center in Bogor city b. Shrubs and secondary forest area under the jurisdiction of PT. Perhutani, Unit III,

KPH (forest district) Bogor: After shrubs or secondary forests were cut for land preparation, using the wood material, charcoal was produced. Charcoal production was conducted mainly from July until October 2001. Some of the produced charcoal were clashed and put in the planting holes for accelerating the growth of seedlings.

After charcoal production, Acacia mangium (in Marbaya), Shorea leprosula (in Ngasuh) and Pinus merkusii (in Cianten) were planted at three locations from the end of 2001 until the beginning of 2002.

Many local residents had been experienced charcoal making before this project started. Earth pit kiln is the common method in this area. i. <Maribaya>: RPH (ranger district) Maribaya, BKPH (forest subdistrict)

Parungpanjang: Charcoal making is common in this area. ii. <Ngasuh>: RPH Ngasuh, BKPH Jasinga: Charcoal making is common in this

area. Among three sites in West Java, local residents in this area were the most skilled makers.

iii. <Cianten>: RPH Cianten, BKPH Leuwiliang: Only one person in villages around this site had been experienced charcoal making.

7

Fig.1 Location of field trial sites in West Java Notes:

(1) Maribaya: Acacia experimental site (2) Ngasuh: Shorea experimental site (3) Cianten: Pinus experimental site

Fig.2 Location of Toho experimental site of Yayasan Dian Tama

1

2

3

West Kalimantan

Java Island

8

(2) East Kalimantan: See Fig.2 for the map Toho experimental site of Yayasan Dian Tama (Its office is located in

Pontianak, Capital city of West Kalimantan), local NGO for community development.

In the experimental site, several types of kilns had been constructed. Brick kiln (called Sugiura kiln), Yoshimura kiln, drum kiln and other types had been build there. Some of them were introduced by “Kokusai Sumiyaki Kyoryoku Kai”, Japanese NGO of which main members are involved in charcoal industry. Charcoal are utilized for animal husbandry (pigs and chickens); cleaning the hog pen, mixed with feedstuff for good taste of eggs. Paddy, beans and other crops are planted and compost mixed with charcoal is utilized as fertilizer. Laban trees (Vitex pinnata) were planted for material of charcoal (There once had been cooperation study with Center for International Forest Research for planting Laban trees at alang-alang (Imperata cylidrica) field.).

Trials under cooperation with this JICA project for carbonization using Yoshimura kiln (explained later about this kiln) had been conducted in October 2003.

3. Comparison of carbonization efficiency: carbon yield

In the process of carbonization, considerable amount of carbon is emitted to the air. Seifrtiz (1993) stated that approximately 50% of the carbon in the biomass (mainly the trunk and the thicker branches) can be extracted in the form of charcoal. Glazer (2002) compiled previous literatures and calculated average carbon yield of various types of kilns including laboratory furnace, and stated that 49.9% of carbon yield on the average.

It means that half of the total carbon inside raw material will be emitted to the air or stored in the form of half-carbonized matter which is easily decomposed (volatile matter, explained later). To raise the carbon fixation potential, carbon yield must be improved.

Charcoal is composed of (1) moisture, (2) ash content, (3) volatile matter and (4) fixed carbon. To raise carbon yield, not only charcoal yield, but also fixed carbon content must be higher. To calculate carbon yield, percentage of each component in charcoal was measured. Analyses of charcoal were conducted in Forest Product Technology Research and Development Center according to the process indicated in the SNI (Standard Nasional Indonesia).

(1) Moisture content: Moisture content of charcoal immediately after finishing carbonization in the kiln was close to 0%. After unloading charcoal from the kiln, charcoal absorbs moisture from the air. In some cases of earth pit or other types of kilns, charcoal was watered after opening the kiln and moisture content of charcoal became higher.

Moisture content of charcoal is calculated as follows:

9

Weight of charcoal – Oven dried weight of charcoal Moisture content (%) = ――――――――――――――――――――――― x 100

Weight of charcoal (2) Ash content: Some kinds of minerals derived from wood material (CaO, K2O,

MgO, etc.) Ash content of charcoal is calculated as follows:

Weight of ash in charcoal

Ash content (%) = ――――――――――――――― x 100 Oven dried weight of charcoal

Formula indicated above is different from that of SNI. SNI uses (fresh) weight

of charcoal as a denominator in the formula (it is the same for volatile matter content). For moisture content of charcoal can vary due to the time after unloading charcoal from kilns or moisture content of the air. Therefore, in this report, the above formula is applied for accurate comparison of charcoal quality among data from various sites.

(3) Volatile matter: It comprises all those liquid and tarry residues not fully driven off

in the process of carbonization. If the carbonization is prolonged and at a high temperature, then the content of volatiles is low. (FAO, 1987)

Volatile matter content of charcoal is calculated as follows:

Weight of volatile matter in charcoal Volatile matter content (%) = ―――――――――――――――― x 100

Oven dried weight of charcoal (4) Fixed carbon = Pure carbon

Fixed carbon content of charcoal is calculated as follows:

Fixed carbon content (%) = 100 – Ash content – Volatile matter content

Formula indicated above is also different from that of SNI. In the case of SNI, Fixed carbon content (%) = 100 – Moisture content - Ash content – Volatile matter content. For the reason already mentioned above (for more accurate comparison), the above formula is used in this report.

Pure carbon in charcoal is difficult to be decomposed. According to Seifritz (1993), it shows no chemical affinity to the oxygen of the air and it does not rot, neither in an aerobic nor in an anaerobic way. This component mainly contributes to carbon storage.

(5) Charcoal yield and carbon yield

Usually, efficiency of charcoal production is indicated by charcoal yield. Charcoal

yield is calculated using formula mentioned below:

10

Weight of charcoal (kg) Charcoal yield (%) = ――――――――――――――――――――――― x 100 Oven dry weight of wood material (kg)

This indicator, however, cannot explain the efficiency of carbon fixation potential.

Instead, ‘carbon yield’ is used in this paper. It expresses the percentage of pure carbon derived from wood material which is preserved in the produced charcoal. Carbon yield is calculated using formula mentioned below:

Carbon yield (%) =

Weight of charcoal (kg) Fixed carbon content (%) 100 - Moisture content (%) ――――――――――――――――― x ――――――――――― x ――――――――――― x 100

0.5 x Oven dry weight of wood material (kg) 100 100

The above formula indicates how many percent of carbon in wood material is stored in produced charcoal in the form of pure carbon. In this equation, it is presumed that carbon content of wood material is 50% as shown in Fig.3.

Fig.3 Carbon in wood material and pure carbon in charcoal

Data obtained from field survey in West Java and East Kalimantan were compared with other previous studies and effective charcoal production methods were determined. 4. Comparison of cost efficiency

Not only production costs per ton charcoal, but also per ton carbon were calculated and compared. Costs of charcoal production by the kilns which were tried by this project were analyzed in this report.

Transportation costs were not included. Costs for collecting wood material were analyzed in the next chapter.

Costs per ton carbon were converted to US dollars. The exchange rate applied in this report is 1US$=Rp.8,610 (in 14, April 2004).

11

5. Estimation of carbon fixation potential by charcoal production

Viability of carbonization projects in several conditions mentioned below was examined:

(1) Wood material after slashing shrubs or secondary forests is carbonized. (2) Wood residues after logging Acacia mangium plantations are carbonized. (3) Carbonizing slabs and sawdust at sawmill. For the estimation of carbon fixation potential, the amount of wood residues must be

estimated. Amount of wood material obtained from shrubs, secondary forests in the three sites in West Java, and total amount of charcoal and carbon produced were estimated using field data. For Acacia mangium, data from West Java (RPH Maribaya and Tenjo, BKPH Parungpanjang, KPH Bogor, Perhutai Unit III) were compared with that from PT. MHP, South Sumatra.

The amount of sawdust residue was estimated from field survey, statistical data and previous literatures.

12

III. Types of kilns for field trials 1. Nonpermanent kiln

1-a. Earth pit kiln

This type of charcoal production is very common in West Java. It is called “Cara timbun” in Indonesian language and “Fuseyaki” in Japanese (earth mound kiln is also called by these terms). Some of village residents were very skilled makers and using only materials obtained in the filed (for example, wood, bamboo, soil, grasses and leaves) (Photo 4). Wood materials piled up in the earth pit are covered by leaves, grasses and soil.

Working process of earth pit kiln was shown in Photo 5 to 13. Sites with slope facing windward are usually chosen to build kilns.

Photo 4 Earth pit kiln in Ngasuh. After logging Pinus merkusii plantation of PT. Perhutani, some part of wood residue (wood of less than 10cm in diameter or wood with scars by taking resin) was given to local people. Local people produce charcoal from the material.

Photo 5 Digging earth pit (Maribaya)

13

Photo 6 Wood materials were piled up in the pit. A gentle slope was made for more smooth ventilation. (Maribaya)

Photo 7 Local people prefer smaller sized kiln. (Maribaya)

Photo 8 Wood material was covered by leaves. Later, this was covered by soil. (Maribaya)

14

Photo 9 Kiln is covered by soil. Kiln wall is made by bamboo. (Maribaya)

Photo 10 Checking the smoke coming out from the rear part of the kiln (Maribaya)

Photo 11 Smoke exits from the chink of rear wall made by wood. ( Ngasuh)

15

Photo 12 Carbonization was finished. (Ngasuh)

Photo 13 Collecting fragmented charcoal. (Ngasuh)

Photo 14 Earth pit kiln at sawmill. The kilns is covered by soil and sawdust. From the front side of the kiln, charcoal had been already collected and stored in sacks (karung).

16

At a sawmill near Jasinga town (located between Maribaya and Ngasuh experimental site, see Fig.1), one charcoal maker produce charcoal using wood residues from sawmill by the earth pit kiln method (Photo 14). Although, around Jasinga town, there are many sawmills, only one sawmill producing charcoal could be found.

1-b. Modified earth pit kiln: Brick floor and galvanized iron sheet for closing kiln

In the trial of earth pit kiln at Forest Products Technology Research and

Development Center, some amount of wood material was not fully carbonized. From the fear of producing low quality of charcoal and to reduce half-raw

charcoal and increase the carbon yield, some modification has been made. For example, kiln’s floor was covered by bricks to reduce effects of soil moisture (Photo 15 and 18). Chimney was installed for more smooth ventilation (Photo 15). In some trials, galvanized iron sheets were used to cover the top of kilns following the method of “Fuseyaki” in Japan (Photo 17).

Field trials were conducted in Forest Products Technology Research and Development Center and three locations (Maribaya, Ngasuh and Cianten) in West Java.

Photo 15 Covering kiln floor with bricks Arrangement of bricks was similar with that of flat kiln. (Bogor, Forest Products Technology Research and Development Center)

17

Photo 16 Two lines of flues which connect with chimney were made. (Forest Products Technology Research and Development Center)

Photo 17 The kiln was covered with galvanized iron sheets. (Bogor)

18

Photo 18 Brick floor trial in Cianten. At the rear part of the kiln, space for chimney was made.

1-c. Sawdust mound kiln This types of kiln is already applied at sawmills in Malaysia (Photo 19 and 20).

At large scale sawmills, heavy machinery can be used to carry and piling up wood materials (Photo 21). For the fire often goes up and sawdust can be burnt, charcoal production by this kiln needs vigilance.

Photo 19 and 20 Sawdust mound kiln in a sawmill in Malaysia Width:7m, Length:20m, Height:2m Wood material: 50m3, Sawdust: 13m3 (Information from Mr. Furumoto, Hyonen Kogyo. Co. Ltd.)

19

20

19

Photo 21 Heavy machinery can be used to carry wood residues at large scale sawmills. (Malaysia)

Following the guidance by Mr. Furumoto, Hyonen Kyogo Co. Ltd., sawdust mound kiln was built in Ngasuh, Shorea experimental site. Photo 22 to 27 show working process for the kiln. This type of kiln can produce larger amount of charcoal at once. The carbonization process, however, must be watched overnight for the fear of exiting fire from sawdust.

Photo 22 Start loading wood material for sawdust mound kiln. Three poles are located vertically to secure the insufflations. (Ngasuh)

20

Photo 23 Loading wood material was finished. (Ngasuh)

Photo 24 Covering kiln with sawdust. (Ngasuh)

21

Photo 25 The rear part of the kiln. Slabs from a sawmill were utilized for the kiln wall. (Ngasuh)

Photo 26 Kiln volume reached 10m3. (Ngasuh)

22

Photo 27 Ignition (in Ngasuh)

2. Movable kiln

2-a. Single drum kiln: Air inlets at the side of drum A drum kiln comprises a recycled oil drum with a chimney made of galvanized

iron. This method is common in Indonesia and often used for carbonizing coconut shell. Around sites for field trial in West Java, however, utilization of this kiln could not be observed.

Although the amount of charcoal produced at once is limited because of kiln size, it needs only 1 day for carbonization and can be used at least 100 times according to Okimori et al. (2003).

Data obtained from field trials (conducted in October 2001) in Ngasuh and Cianten were recorded and compared. Drum kiln was used also in Maribaya (Photo 28), but no measurement was conducted.

Photo 28 Drum kiln (Maribaya)

23

Air inlets are located at the side of kiln. Chimney and cover of the kiln can be detached (Photo 30). Burned fuel wood (starter) is put into the kiln from the top. At first air inlets near the bottom of kiln are opened. After finishing carbonization at the bottom zone of kiln, the air inlets are closed and the above inlets are opened. This is to equalize the quality of charcoal.

2-b. Single drum kiln: Air inlets at the bottom of drum

If air inlets are located at the side of kiln, charcoal makers must carefully watch

the kiln during the whole carbonization process. For easier control and possibility to reduce workforce for charcoal production, the air inlets were moved to the bottom (Photo 29 to 31).

Once ignited from the bottom of the kiln (Photo 31), charcoal makers only watches the color of the smoke from the chimney. As same as the other types of kiln, if smoke color turns into thin blue, bricks under the kiln (Photo 31) are removed and the side bottom are closed by soil.

Field trials were conducted in Ngasuh and Cianten in July 2002.

Photo 29 Experiment in Cianten. Air inlets at the side of kiln were closed. Instead, holes were made at the bottom of the kiln.

24

Photo 30 Wood material was put from the top of the kiln. At the center of the kiln, one larger sized wood are located as shown in the Photo. After filling the kiln with wood material, this wood was pulled out.(in Cianten)

Photo 31 Fuel wood for starter is under the kiln. Ignited from the bottom of the kiln. (Toho experimental site of Yayasan Dian Tama, West Kalimantan)

2-c. Double drum kiln In Forest Products Technology Research and Development Center in Bogor,

double drum kiln was tried once. Two oil drums were cut and opened and reconnected. The trial was conducted in June 2001.

3. Permanent kiln: Yoshimura kiln

For the comparison with nonpermanent and movable kiln, trials of permanent kiln were conducted in Toho experimental site of Yayasan Dian Tama, West Kalimantan. This kiln was named after a Japanese charcoal maker who introduced this kiln to Yayasan Dian Tama.

Although there were four Yoshimura kilns before the corporation with this project, before starting trials, some repairing was needed (Photo 32). Photo 33 to 37 show

25

working process of charcoal production. As shown in Fig. 4, firing port of this kiln is separated from main body of the kiln. This is to avoid burning of wood material and maintain the good shape of produced charcoal. This type of kiln needs larger amount of fuel wood for starter.

As seen in Photo 33, evenly sized wood material was utilized. Wood material was put into the kiln vertically. Trial using smaller and not-evenly sized material was not conducted. In the trials, some part of wood material became ash (Photo 37).

Wood vinegar was collected using bamboo (Photo 38).

Photo 32 Repairing kiln floor

Photo 33 Loading wood material

26

Fig. 4 Kiln profile Firing port is separated from space for wood material. This is to produce good-shaped charcoal.

Photo 34 Wood material was covered by leaves of tree and palm

27

Photo 35 After closing kiln by iron cover, kiln top was covered with soil.

Photo 36 Ignition. Larger amount of fuel wood for starter is needed.

28

Photo 37 Carbonization was finished.

Photo 38 Collecting wood vinegar using bamboo

4. Kiln for producing sawdust charcoal: flat kiln

A flat kiln is a modified type of earth pit kiln with brick on the floor and sidewalls.

Usually, it is used for producing materials of activated carbon, briquette charcoal and so on. Sawdust and tree bark can be carbonized using this kiln. In large-scale activated charcoal factories, many kilns are combined and flues are connected to a single large-sized chimney (Photo 39 and 40).

In Forest Products Technology Research and Development Center, a small sized flat kiln was constructed (Photo 41). Fig. 5 shows the size and profile of the kiln. Process of kiln construction and carbonization are explained in another report (Gustan Pari, et al. 2004).

29

Photo 39 Flat kiln in an activated charcoal factory Kiln volume is about 7.7m3. Length of the kiln reachs 7m. (Parungpanjang town , West Java)

Photo 40 Flues under the kilns are connected to one large sized chimney. (Parungpanjang, West Java)

Because the kiln does not have a roof, carbonization temperature is low (250 to 300 degrees Celsius) according to Mr. Sugai, Director of Hokuetsu Shoji Co. Ltd. (Personal communication). The air enters into the kiln through an interstice of sawdust particles, goes to the kiln floor and finally it exits from the chimney. Carbonization starts at the bottom of the kiln, and proceeds to the top of the kiln (surface of sawdust). The speed of carbonization depends on the size of sawdust particles and intensity of the air suction in the chimney (according to Mr. Sugai, Personal communication).

Carbonization tests were conducted three times at Forest Product Technology Research and Development Center in September 2002 and June 2003. After finishing 2nd trial, the location of the chimney was changed to improve its ventilation.

Chimney

30

Photo 41 Flat kiln (Forest Product Technology Research and Development Center) In the 3rd trial. Raw material (sawdust brought from sawmill) was prepared beside the kiln.

31

Fig. 5 Size of flat kiln constructed in Forest Products Technology Research and Development Center

32

IV. Comparison of carbonization efficiency 1. Nonpermanent kilns

Lists of data obtained from field trials are indicated in Table 1. For not all trials,

fresh weight of wood material was not measured. In such case, dry weight of wood material was estimated from kiln volume. Table 2 and 3 are additional data for the estimation.

Table 4 is the summary of those data indicated in Table 1. Several facts were found:

(1) Using brick floor improved the quality of charcoal (higher fixed carbon content)

and decrease half-carbonized material. The amount of ash (separated from charcoal for analyses), however, increased and charcoal yield decreased. For these reasons, carbon yield decreased.

(2) Using galvanized iron sheet to cover the kiln increased the quality of charcoal. For the same reasons with brick floor kilns, however, carbon yield decreased.

(3) In the case of sawdust mound, carbon yield was still low. It was partly because local people in West Java were still not used to large-sized kiln. Workers should be trained to maintain higher efficiency for large sized kiln.

Sawdust mound kiln must be watched overnight for the fear of forest fire. This method is usually applied in sawmills for carbonizing wood residue. It is recommended that this sawdust mound is conducted in or around sawmills.

(4) It became clear that earth pit could produce relatively higher quality of charcoal. (5) Skill of workers seems to affect quality of charcoal and carbon yield. At Cianten,

where only one person had experience of charcoal making, carbonization efficiency was lower.

Fig. 6 shows relationship between kiln volume and carbon yield. To increase the

amount of charcoal produced at once and increase the yield and quality of charcoal, larger sized kilns were tried. Charcoal makers in the experimental sites, however, were not familiar with large size kilns and the results were, as shown in the Figure, that the larger was the size of kiln, the lower was the carbon yield.

33

Table

1 D

ata

list

of n

onpe

rman

ent

kiln

(Trial

s in

Wes

t Jav

a)C

har

coa

l an

alys

isR

aw m

ater

Kiln

No.

Typ

e o

f ki

ln 1

)Loc

atio

n 2

)

Mois

ture

conte

nt

(%)

Ash

con

tent

(%)

Vola

tile

mat

ter

conte

nt

(%)

Fix

ed c

arbon

cont

ent

(%)

pH

Num

ber

of

sam

ple

s fo

rch

arcoal

anal

ysis

Kiln

vol

ume

(m3)

Vol

um

e o

fra

w m

aterial

/ V

olum

e o

f

kiln

(%) 3

)

Woo

ddensi

ty

(kg/

m3) 3

)

Fre

shw

eig

ht

ofw

ood

mat

erial

(kg

)

1Ear

th p

itB

ogo

r5.

45

2.3

615

.45

82.1

9n.

a.6

n.a.

700

2Ear

th p

itB

ogo

r7.

77

1.5

59.

56

88.9

0n.

a.6

n.a.

1000

3Ear

th p

itB

ogo

r4.

42

2.6

916

.71

80.6

1n.

a.9

n.a.

993

4Ear

th p

itM

arib

aya

2.82

3.7

119

.51

76.7

88.

99

99.2

466.

07

522.

03

5Ear

th p

itM

arib

aya

4.17

2.6

219

.80

77.5

98.

90

93.9

166.

07

522.

03

6Ear

th p

itM

arib

aya

6.81

2.2

817

.82

79.9

18.

88

93.5

266.

07

522.

03

7Ear

th p

itM

arib

aya

5.41

1.8

720

.23

77.8

98.

83

94.4

066.

07

522.

03

8Ear

th p

itN

gasu

h5.

00

3.0

59.

57

87.3

89.

02

92.7

666.

07

390.

28

9Ear

th p

itN

gasu

h2.

41

1.6

320

.54

77.8

28.

19

93.0

066.

07

390.

28

10

Ear

th p

itN

gasu

h2.

26

2.3

120

.60

77.0

98.

98

62.6

366.

07

390.

28

11

Ear

th p

itN

gasu

h3.

81

1.6

521

.10

77.2

58.

45

93.0

066.

07

390.

28

12

Ear

th p

itN

gasu

h6.

40

2.5

920

.46

76.9

59.

26

92.4

066.

07

390.

28

13

Brick

flo

or

Mar

ibay

a4.

26

1.5

117

.28

81.2

19.

30

93.8

466.

07

522.

03

14

Brick

flo

or

Nga

suh

4.48

1.8

017

.84

80.3

68.

40

92.7

666.

07

390.

28

15

Brick

flo

or

Nga

suh

11.1

32.0

211

.95

86.0

2n.

a.9

2.7

666.

07

390.

28

16

Brick

flo

or

Nga

suh

7.37

1.6

412

.92

85.4

4n.

a.5

2.7

666.

07

390.

28

17

Brick

flo

or

Cia

nte

n8.

09

1.8

623

.85

74.2

98.

64

94.0

866.

07

415.

40

18

Brick

flo

or

Cia

nte

n17

.62

1.8

319

.61

78.5

58.

95

98.6

366.

07

415.

40

19

Brick

flo

or

Cia

nte

n4.

39

2.2

411

.79

85.9

79.

30

92.6

311

90

20

GIS

Mar

ibay

a7.

18

2.8

511

.79

85.3

6n.

a.7

3.6

066.

07

522.

03

21

GIS

Nga

suh

8.48

5.0

210

.45

84.5

39.

11

64.2

019

92.6

22

Brick

flo

or +

GIS

Bogo

r20

.55

4.1

812

.38

83.4

5n.

a.9

n.a.

664.6

23

Brick

flo

rr +

GIS

Bogo

r34

.19

1.7

713

.01

85.2

29.

43

92.2

510

96.5

24

Saw

dust

mou

nd

Nga

suh

4.33

2.0

019

.02

78.9

89.

08

910.

00

66.

07

390.

28

Note

s:1) G

IS-

Gal

vaniz

ed

iron s

heet

on t

he t

op o

f th

e ki

ln. B

rick

flo

or

+ G

IS -

Gal

vaniz

ed

iron s

heet

on t

he t

op a

nd b

ricks

on t

he f

loor.

2) B

ogo

r - F

orest

Pro

ducts

Technol

ogy

Rese

arch a

nd D

eve

lope

nt

Cen

ter

3) R

efe

r to

Tab

le 2

and

3.

4) F

igure

s in

par

enth

ese

s : car

boniz

atio

n t

ime e

xclu

din

g tim

e f

or

coolin

g do

wn.

34

rial

Char

coal

, car

bon

Oth

er

info

rmat

ion

(Weig

ht

of

raw

mat

erial

)M

:Meas

ure

dE:E

stim

ated

Moi

sture

cont

ent

ofra

w m

aterial

(%)

Dry

wig

ht

of

woo

dm

aterial

(kg

)

Wei

ght

of

char

coa

l(k

g)

Cha

rcoal

yield

(%)

Car

bon y

ield

(%)

Car

boniz

atio

n

tim

e (

day

) 4)

Uncar

bon

ized

mat

erial

(kg

)Tem

pera

ture

(degr

ee C

els

ius)

Kiln

No.

M17.0

1580.9

104.0

17.9

027.7

25

25

Acai

ca

man

gium

(60%), P

inus

merk

usi

i(20%), A

lbiz

ia(2

0%)

1M

14.2

2857.8

165.2

19.2

631.3

53

148

Acac

ia m

angi

um

(60%), P

inus

merk

usi

i(20%), G

melin

a ar

bore

a(10%), C

alia

ndr

a(10%)

2M

38.8

4607.3

102.5

16.8

825.8

910

2.5

3E

3186.9

398.0

12.4

918.6

29

4E

1348.6

259.0

19.2

128.4

710

5E

1214.1

202.5

16.6

824.6

97

6E

1517.6

350.0

23.0

633.8

5n.a

.7

E711.7

175.0

24.5

940.6

8(2

)8

E773.6

199.8

25.8

339.2

1(2

)9

E676.9

183.6

27.1

240.8

5(3

)10

E773.6

180.0

23.2

734.5

3(3

)11

E618.9

118.0

19.0

727.2

0(2

)12

E1324.4

168.0

12.6

819.6

85

13

E711.7

159.5

22.4

134.3

3(2

)14

E711.7

162.5

22.8

333.1

3(2

)15

E711.7

175.0

24.5

938.6

7(3

)16

E1119.8

135.0

12.0

616.2

34

17

E2367.2

198.0

8.3

69.4

74

18

M45.5

0648.5

76.0

11.7

219.2

25

19

E1241.7

73.0

5.8

89.2

5n.a

.20

M43.5

01125.8

89.7

7.9

712.1

9n.a

.21

M24.1

4504.2

120.0

23.8

028.1

3n.a

.R

ubb

er

22

M48.0

1570.0

92.5

16.2

311.1

47

Acac

ia m

angi

um

23

E2578.6

405.0

15.7

123.6

613

24

35

Table 4 Comparison of carbon yield (Summary of nonpermanent kiln)

Location Type of kilnNo. of

samplesFixed carboncontent (%)

Charcoal yield(%)

Carbon yield (%)

Bogor Earth pit 3 83.90 18.01 28.32Brick floor and GIS 2 84.33 20.02 19.63

Maribaya Earth pit 4 78.04 17.86 26.41Brick floor 1 81.21 12.68 19.68GIS on the top 1 85.36 5.88 9.25

Ngasuh Earth pit 5 79.30 23.98 36.49Brick floor 3 83.94 23.28 35.38Sawdust mound 1 78.98 15.71 23.66GIS on the top 1 84.53 7.97 12.19

Cianten Brick floor 3 79.60 10.71 14.97All locations Earth pit 12 80.03 20.45 31.09

Brick floor 7 81.69 16.38 24.39All 24 81.24 17.90 26.17

Table 2 Calculation of volume of raw material / kiln volume

No. of kilnin Table 1

LocationKiln volume

(m3)

Fresh weight ofwood material

(kg)

Moisture contentof wood material

(%)

Dry weight ofwood material

(kg)

Wood density

(kg/m3) 2)

Volume ofwood material

(m3)

Volume of rawmaterial/KilnVolume (%)

a b c d=b*(1-c/100) e f=d/e g=100*f/a

21 Ngasuh 4.20 1992.60 43.50 1125.76 390.28 2.88 68.6819 Cianten 2.63 1190.00 45.50 648.50 415.40 1.56 59.31

n.a. 1) Cianten 2.09 1193.50 45.50 650.41 415.40 1.57 74.83

23 Bogor 2.25 1096.50 48.01 570.02 412.48 1.38 61.45Average 66.07 %

3)

Notes: 1) This data is not included in Table 1 because no charcoal analysis was made.

2) Refer to Table 3.

3) This figure is utilized in Table 1 for estimating volume of raw material.

Table 3 Wood density in each experimental site + Acacia mangium (BKPH Parungpanjang, KPH Bogor)Location,species

Wood density

(kg/m3) 1)

Number ofsamples

Species

Maribaya average 522.03 20 Schima sp., Fagraea sp. etc.

Ngasuh average 390.28 19 Maesopsis sp., Bellucia sp., Schima sp. etc.

Cianten average 415.40 20 Macaranga sp., Maesopsis sp., etc.

Acacia mangium 412.48 59Notes: Data were obtained in forest area under jurisdiction of PT. Perhutani, Unit III, KPH Bogor.

1) Wood density = (oven dry stem weight) / (stem volume)

2) Data obtained from tree census conducted in shrubs and secodary forests adjacent to kiln sites.

Diameter (DBH) 2), or standage

3, 5 8 and 10 years old stand

Max=38.2cm, mostly under 20cm

Max=43.3cm, mostly under 20cm

Max=7.9cm

36

Fig. 6 Relationship between kiln volume and carbon yield 2. Movable kilns: drum kilns

Table 5 is the list of data from field trials and analyses of charcoal quality. Single drum kilns were tried at Ngasuh and Cianten experimental sites. The reason of low charcoal and carbon yield was still not known clearly. One of the reasons can be skill of workers. Some technicians at the Forest Products Research and Development Center stated that higher moisture content in the air (altitude of Cianten experimental site is more than 900m and annual rainfall is above 4,000mm.) affected the yield.

Carbonization efficiency was compared in each experimental site as shown in Table 6 and Fig. 7. It is apparent that there was no reverse effect of moving air inlets from the side to the bottom of drum. Drum kiln with air inlets at the bottom is easier to control and could reduce the number of workers to watch the carbonization process.

Double drum kiln was tried once at the Forest Products Technology Research and Development Center. The result, however, was not good from the aspects of carbon yield and amount of produced charcoal.

37

Table 5 Data list of drum kilnSingle drum kiln: Air inlets at the side

Charcoal analysis Raw materialNo. Location

Moisturecontent (%)

Ashcontent

(%)

Volatilematter

content (%)

Fixedcarbon

content (%)pH

No. ofsamples for

analysis

Fresh weight ofraw material

(kg)

Moisturecontent (%)

Dry weight ofraw material

(kg)

Weight ofcharcoal

(kg)

1 Ngasuh 3.50 3.04 11.56 85.40 1 38.00 21.06 30.00 5.802 Ngasuh 4.43 2.30 12.43 85.27 1 39.00 21.06 30.79 6.203 Ngasuh 3.18 2.40 11.59 86.01 1 37.00 21.06 29.21 6.104 Ngasuh 4.95 2.08 11.67 86.25 1 40.00 21.06 31.58 6.005 Ngasuh 4.37 3.07 12.16 84.77 1 40.00 21.06 31.58 6.106 Ngasuh 7.46 2.81 11.27 85.92 1 40.00 23.73 30.51 6.357 Ngasuh 9.03 1.64 11.40 86.96 1 40.00 21.06 31.58 6.138 Ngasuh 6.95 3.55 11.62 84.83 1 40.00 21.06 31.58 5.939 Ngasuh 5.46 1.41 11.34 87.25 1 40.00 21.06 31.58 5.8710 Ngasuh 8.85 2.37 11.84 85.79 1 40.00 21.06 31.58 6.2111 Ngasuh 5.20 1.09 11.89 87.02 1 40.00 21.06 31.58 7.2012 Ngasuh 4.80 2.28 11.05 86.67 1 40.00 21.06 31.58 7.2013 Ngasuh 4.19 1.60 11.67 86.73 1 40.00 21.06 31.58 8.6014 Ngasuh 3.48 2.76 10.82 86.42 1 40.00 21.06 31.58 8.4015 Ngasuh 2.94 1.90 10.52 87.58 1 40.00 21.06 31.58 8.0016 Cianten 5.07 1.37 6.43 92.20 1 34.70 27.59 25.12 5.0017 Cianten 5.20 2.13 7.62 90.25 1 52.00 19.30 41.96 7.0018 Cianten 4.49 3.21 9.72 87.07 1 46.00 26.48 33.82 5.8019 Cianten 5.91 4.01 8.55 87.44 1 49.20 27.19 35.82 6.4020 Cianten 6.79 3.61 8.41 87.98 1 48.00 24.11 36.43 6.0021 Cianten 4.37 3.76 7.56 88.68 1 49.20 24.11 37.34 5.8022 Cianten 4.43 1.33 9.29 89.38 1 50.00 24.11 37.94 7.2023 Cianten 3.59 1.55 10.88 87.57 1 49.20 19.34 39.68 6.00

Average 5.16 2.40 10.49 87.11 42.27 22.21 32.87 6.49

Single drum kiln: Air inlets at the bottomCharcoal analysis Raw material

No. LocationMoisture

content (%)

Ashcontent

(%)

Volatilematter

content (%)

Fixedcarbon

content (%)pH

No. ofsamples for

analysis

Fresh weight ofraw material

(kg)

Moisturecontent (%)

Dry weight ofraw material

(kg)

Weight ofcharcoal

(kg)

1 Ngasuh 6.26 2.22 11.42 86.36 9.05 6 50.00 28.94 35.53 7.352 Ngasuh 4.70 2.42 13.58 84.00 8.69 6 50.00 28.69 35.66 9.153 Ngasuh 3.71 2.21 13.65 84.14 9.00 6 50.00 34.92 32.54 8.294 Ngasuh 5.36 2.86 11.12 86.03 8.98 6 57.50 29.69 40.43 9.155 Ngasuh 6.59 2.39 13.38 84.23 8.88 6 50.00 28.69 35.66 9.656 Ngasuh 6.74 2.24 12.12 85.64 8.76 6 50.00 34.92 32.54 9.307 Ngasuh 7.00 2.94 12.53 84.53 9.08 6 45.00 28.94 31.98 8.308 Ngasuh 5.91 2.70 10.31 86.99 8.89 6 50.00 28.69 35.66 9.309 Ngasuh 4.88 2.45 11.80 85.76 8.72 6 50.00 34.92 32.54 9.6510 Ngasuh 7.19 3.32 11.19 85.49 8.86 6 48.00 28.94 34.11 7.7011 Ngasuh 7.10 3.08 10.14 86.78 8.88 6 50.00 28.69 35.66 10.6012 Ngasuh 5.79 2.47 10.35 87.18 8.75 6 50.00 34.92 32.54 10.9013 Cianten 6.55 5.63 14.06 80.30 9.93 3 50.00 22.73 38.63 5.5014 Cianten 7.12 2.01 11.03 86.96 10.17 3 50.00 28.66 35.67 4.8015 Cianten 6.42 3.63 12.54 83.83 9.71 3 50.00 28.09 35.96 8.5016 Cianten 4.65 3.75 20.82 75.43 9.71 3 50.00 22.73 38.63 7.0017 Cianten 6.79 2.23 10.23 87.54 9.66 3 50.00 28.66 35.67 3.7018 Cianten 6.83 1.89 11.04 87.07 9.75 3 50.00 28.09 35.96 8.1019 Cianten 7.57 2.59 8.73 88.68 9.81 3 50.00 22.73 38.63 6.3020 Cianten 7.54 2.98 10.57 86.46 9.75 3 50.00 28.66 35.67 3.4521 Cianten 7.45 3.12 9.50 87.39 9.82 3 50.00 28.09 35.96 11.2022 Cianten 7.21 3.13 10.86 86.01 9.75 3 50.00 22.73 38.63 8.3023 Cianten 7.44 2.78 11.31 85.90 9.89 3 50.00 28.66 35.67 4.2024 Cianten 6.27 3.20 10.88 85.92 9.69 3 50.00 28.09 35.96 8.80

Average 6.38 2.84 11.80 85.36 9.34 50.02 28.70 35.66 7.88

Double drum kilnCharcoal analysis Raw material

No. LocationMoisture

content (%)

Ashcontent

(%)

Volatilematter

content (%)

Fixedcarbon

content (%)pH

No. ofsamples for

analysis

Fresh weight ofraw material

(kg)

Moisturecontent (%)

Dry weight ofraw material

(kg)

Weight ofcharcoal

(kg)

1 Bogor 8.63 2.68 10.47 86.85 9.07 1 77.50 17.82 63.69 10.50

38

Charcoal, carbon

Charcoal yield(%)

Carbonyield (%)

Carbonizationtime (hours)

Temperature (highest)

Date

19.34 31.87 5.75 2/October/200120.14 32.83 5.25 2/October/200120.89 34.79 4.50 2/October/200119.00 31.16 5.20 2/October/200119.32 31.32 5.00 2/October/200120.82 33.10 4.20 3/October/200119.41 30.71 4.15 3/October/200118.78 29.65 4.05 3/October/200118.59 30.67 4.25 3/October/200119.67 30.76 4.00 3/October/200122.80 37.62 5.27 4/October/200122.80 37.63 5.27 4/October/200127.24 45.27 4.12 4/October/200126.60 44.38 4.08 4/October/200125.34 43.07 5.00 4/October/200119.90 34.84 5.45 9/October/200116.68 28.55 6.00 9/October/200117.15 28.52 5.30 9/October/200117.87 29.40 6.00 10/October/200116.47 27.02 6.00 10/October/200115.53 26.35 6.00 10/October/200118.97 32.42 6.00 10/October/200115.12 25.53 6.00 10/October/200119.93 32.93

Charcoal, carbon

Charcoal yield(%)

Carbonyield (%)

Carbonizationtime (hours)

Temperature (highest)

Date

20.69 33.49 6.05 605 18/June/200225.66 41.09 6.14 580 18/June/200225.48 41.28 4.20 590 18/June/200222.63 36.85 6.14 580 18/June/200227.06 42.59 4.16 600 18/June/200228.58 45.65 4.30 685 18/June/200225.96 40.81 4.29 630 18/June/200226.08 42.70 4.30 685 18/June/200229.66 48.39 4.58 680 18/June/200222.57 35.82 3.18 680 18/June/200229.73 47.93 4.35 665 18/June/200233.50 55.03 3.40 600 18/June/200214.24 21.37 4.50 18/June/200213.46 21.74 6.15 18/June/200223.64 37.09 4.75 18/June/200218.12 26.06 4.10 18/June/200210.37 16.93 7.20 18/June/200222.53 36.55 5.00 18/June/200216.31 26.73 4.45 18/June/20029.67 15.46 8.20 18/June/200231.15 50.39 6.70 18/June/200221.48 34.29 5.55 18/June/200211.77 18.72 7.10 18/June/200224.47 39.42 5.25 18/June/200222.28 35.68 5.17

Charcoal, carbon

Charcoal yield(%)

Carbonyield (%)

Carbonizationtime (hours)

Temperature (highest)

Date

16.49 26.17 4.50 29/June/2001

39

Table 6 Comparison of efficiency for carbonization (Summary of drum kiln)

Location Type of kilnNo. of

samples

Fixed carboncontent (%)

(excluding moisture)

Charcoal yield (%)(fresh weight/dry

weight)

Carbonyield (%)

Ngasuh Air inlets at the side 15 86.19 21.38 34.99Air inlets at the bottom 12 85.59 26.47 42.64Average 27 85.93 23.64 38.39

Cianten Air inlets at the side 8 88.82 17.21 29.08Air inlets at the bottom 12 85.12 18.10 28.73Average 20 86.60 17.75 28.87

Bogor Double drum 1 86.85 16.49 26.17Total average (exclude double drum) 47 86.21 21.13 34.34

Ngasuh: side 15 86.19 21.38 34.99Ngasuh: bottom 12 85.59 26.47 42.64Cianten: side 8 88.82 17.21 29.08Cianten: bottom 12 85.12 18.10 28.73Bogor: double 1 86.85 16.49 26.17

Fig. 8 Comparison of efficiency for carbonization (drum kiln)

0

5

10

15

20

25

30

35

40

45

Ngasuh:side

Ngasuh:bottom

Cianten:side

Cianten:bottom

Bogor:double

Type of kiln

Car

bon

yie

ld (%)

40

3. Permanent kiln: Yoshimura kiln

Permanent kiln can produce larger amount of charcoal compared with nonpermanent kilns. This type of kiln requires large amount of fuel wood for starter because of the distance from firing port to main body of the kiln. For this reason, weight of starter cannot be neglected and included in the analysis. As shown in Table 7, in these trials, large amount of wood material became ash and carbon yield was about 33.4%.

According to the Table, 5m3 kiln showed higher efficiency for carbonization. In the case of nonpermanent kiln, larger size of kiln is recommended also from the aspect of cost efficiency (explained later in the next chapter). 4. Flat kiln for sawdust charcoal

Table 8 shows the results of trials using the flat kiln. Because of lower carbonization temperature, higher volatile matter content and lower fixed carbon content were observed.

Because the staffs (technicians and hired labors) in Forest Product Technology Research and Development Center were not familiar with this method, charcoal yield was very low for the first trial. Charcoal yield was improved as the staffs got used to this techniques. Carbon yield could reach 24.2%. 5. Comparison of carbon yield

To evaluate the data obtained by this project, the results from field trials in West Java and East Kalimantan were compared with previous researches as shown in Table 9. The following facts were found:

(1) It is difficult to achieve 50% of carbon yield. Only two cases for single drum kiln (Single drum kiln, air outlets at the bottom, Table 5) showed more than 50% carbon yield. Most cases in Indonesia showed 20 to 40%.

(2) In trials by the project, single drum kiln in Ngasuh experimental site and Yoshimura kiln showed the highest carbon yield (38.39% and 37.85%), although in the case of Yoshimura kiln, large amount of starter was necessary.

(3) Average carbon yield of earth pit kiln was less than 30%. (4) For Mark V kiln (Photo 42), data in Thailand showed higher carbon yield

(42.85%). On the other hand, data in Indonesia showed lower yield (25.21%). This can be partly explained by the high specific gravity of raw material in Thailand. Specific gravity of Acacia catechu is 0.98 according to Nettai Shokubutsu Yoran (in Japanese). Even considering this factor, yield of Indonesia was still low.

(5) Permanent kilns (brick kilns) showed higher yield. It, however, sometimes can be lower according to several factors. More skilled workers are necessary for building kilns and producing charcoal. (See Photo 43 for brick kiln)

(6) If raw material with higher specific gravity was carbonized, carbon yield became higher. As shown in the data by Tjutju et al. (2003), mangrove charcoal showed higher yield than Acacia charcoal. Data from Thailand also supported this fact.

41

Tab

le 7

R

esul

ts: Y

oshi

mur

a ki

lnC

harc

oal a

naly

sis

Kiln

No.

Moi

stur

eco

nten

t (%

)V

olat

ile m

atte

rco

nten

t (%

)A

sh c

onte

nt(%

)Fi

xed

carb

onco

nten

t (%

)pH

Num

ber

ofsa

mpl

es f

orch

arco

al a

naly

sis

Kiln

vol

ume

(m3 )

14.

9415

.94

1.48

82.5

88.

633

52

3.86

18.9

12.

1278

.97

9.47

35

35.

4019

.72

1.64

78.6

48.

473

34

5.63

14.5

03.

8681

.63

8.74

33

Ave

rage

4.96

17.2

72.

2780

.46

8.83

4.40

3333

317

.429

4604

81.

7956

785

80.7

7486

105

77.2

1807

467

Raw

mat

eria

lC

harc

oal,

carb

onO

ther

info

rmat

ion

Kiln

No.

Fres

h w

eigh

tof

woo

dm

ater

ial (

kg)

Moi

stur

e co

nten

tof

raw

mat

eria

l(%

)

Dry

wig

ht o

fw

ood

mat

eria

l(k

g)

Dry

wei

ght

ofst

arte

r (k

g)W

eigh

t of

char

coal

(kg

)C

harc

oal y

ield

(%)

Cha

rcoa

l yie

ld(in

clud

e st

arte

r)(%

)

Car

bon

yiel

d (%

)C

arbo

niza

tion

time

(day

)

Car

boni

zatio

ntim

e(e

xclu

ding

cool

ing

dow

n)

Wei

ght

ofas

h (k

g)

Wei

ght

ofw

ood

vine

gar

(kg)

Tre

e sp

ecie

s fo

r ra

wm

ater

ial

126

84.0

041

.82

1561

.53

158.

842

227

.02

24.5

338

.51

75

6318

Aca

ia m

angi

um2

2352

.00

42.7

713

45.9

970

.39

347

25.7

824

.50

37.2

08

655

14H

eave

a s p

. (R

ubbe

r)3

1243

.00

30.4

286

4.93

83.3

615

918

.38

16.7

724

.95

64

327

Vitex

sp.

(La

ban)

416

71.0

031

.65

1142

.06

73.1

326

022

.77

21.4

032

.97

54

2414

Bel

luci

a sp

.A

vera

ge19

87.5

036

.67

1228

.63

96.4

329

723

.49

21.8

033

.41

64.

7543

.50

13.2

5

Tab

le 8

R

esul

ts: f

lat

kiln

(sa

wdu

st c

harc

oal)

Cha

rcoa

l an

alys

isR

aw m

ater

ial

Cha

rcoa

l, ca

rbon

Trial

sM

oist

ure

cont

ent

(%)

Vol

atile

mat

ter

cont

ent

(%)

Ash

con

tent

(%)

Fix

edca

rbon

cont

ent

(%)

pH

Num

ber

ofsa

mpl

es f

orch

arco

alan

alys

is

Kiln

vol

ume

(m3)

Fre

sh w

eigh

tof

woo

dm

ater

ial (k

g)

Moi

stur

eco

nten

t of

raw

mat

eria

l(%

)

Dry

wig

ht o

fw

ood

mat

eria

l(k

g)

Wei

ght

ofch

arco

al(k

g)

Cha

rcoa

lyi

eld

(%)

Car

bon

yiel

d(%

)

Car

boni

zatio

n tim

e(h

ours

)

Hal

f-ca

rbon

ized

mat

eria

l (k

g)

1st

3.39

24.6

23.

9971

.39

8.63

211

840.

0020

.84

664.

9864

.81

9.75

13.4

436

160

2nd

3.86

23.5

84.

0872

.34

8.80

611

1848

.00

20.8

414

62.9

525

4.60

17.4

024

.21

6048

3rd

2.46

21.0

06.

3572

.65

7.37

611

1787

.00

19.3

114

42.0

022

9.50

15.9

222

.56

7219

2

Oth

er inf

orm

atio

n

42

Table

9

Com

pariso

n: C

arbo

n y

ield

and

oth

er

info

rmat

ion

No.

Typ

e o

f ki

lnSiz

e o

f ki

ln(m

3)

No. of

sam

ple

sM

ois

ture

conte

nt

(%)

Ash

conte

ntV

ola

tile

mat

ter

Fix

ed c

arbon

conte

nt

(%)

Am

ount

of

cha

rcoal

produced

(kg)

Char

coal

yield

(%)

Car

bon y

ield

(%)

Car

boniz

atio

n t

ime (

day

s)Locat

ion

Nonp

erm

anent

kiln

1Ear

th p

it k

iln2.4

-9.2

12

4.7

32.3

617.

6180

.03

203.1

320.

45

31.0

95-1

0W

est

Jav

a, Indonesi

a

22.0

25.8

33.0

79.

29

87.6

414.

00

23.1

13

Purw

osa

ri, G

unung

Kid

ul, Yogy

akar

ta, In

donesi

a

3Ear

th m

oun

d ki

ln2.0

-3.0

47.2

94.1

425.

0368

.16

16.

00

20.2

22-8

Yogy

akar

ta, In

dones

ia

40.7

56.9

63.6

522.

9973

.36

52.9

031.

10

42.4

50.5

Thai

land

598

90*

14.3

*32

.00

6Saw

dust

mou

nd

kiln

10.0

14.3

32.0

019.

0278

.98

405.0

015.

71

23.6

613

Nga

suh, W

est

Jav

a, Ind

onesi

a

70.7

55.6

63.2

519.

0677

.69

50.6

032.

80

48.0

81

Thai

land

Mova

ble

kiln

8Sin

gle

dru

m k

iln0.2

27

5.5

62.4

311.

6485

.93

7.7

623.

64

38.3

91

Nga

suh, W

est

Jav

a, Ind

onesi

a

90.2

20

6.0

82.9

010.

5086

.60

6.4

517.

75

28.8

71

Cia

nte

n, W

est

Jav

a, Indoens

ia

100.2

75.8

73.1

719.

51

77.3

220.

424.2

35.2

21

Thai

land

11M

ark

V k

iln1

6.2

52.3

422.

2775

.05

17.

92

25.2

110

Telu

k D

alam

, Eas

t Kal

iman

tan, In

donesi

a

124.8

23.7

73.8

022.

2773

.24

452.3

030.

40

42.8

5Thai

land

Perm

anent

kiln

13Yos

him

ura

kiln

5.0

24.4

01.8

017.

4380

.77

384.5

026.

40

37.8

510

Toho, W

est

Kal

iman

tan, In

donesi

a

14B

rick

kiln

5.5

13.7

5-4.

21

1.7

0-4.

90

7.5

0-27.

269.

20-8

0.7

045

8.5

30.

00

43.1

85

Bogo

r, W

est

Jav

a, Indones

ia

151

6.3

72.6

120.

97

79.4

223.

42

34.8

3Telu

k D

alam

, Eas

t Kal

iman

tan, In

donesi

a

162.0

22.3

73.7

98.0

75

87.

965

192.

25

26.

95

46.2

810

172.0

27.3

91.4

222.

22

76.

335

111.

520.

97

29.6

59

18B

rick

Bee

hiv

e k

iln8.3

319

.29

74.8

8976.

30

39.6

047

.87

4Thai

land

Kiln

for

saw

dust

char

coal

19Fla

t ki

ln11

.03

3.2

34.8

123.

0772

.13

182.9

714.

35

20.0

72

Bogo

r, W

est

Jav

a, Indones

ia

Continue

No.

Typ

e o

f ki

lnW

ood m

aterial

Litera

ture

1Ear

th p

it k

ilnSeconda

ry f

ore

st s

peci

es

The p

roje

ct

2Teak

, A

cac

ia m

angi

um

Sri N

ugr

oho, et

al. (2

004)

3Ear

th m

oun

d ki

lnD

albe

rgia

lat

ifolia

, te

ak, A

cac

ia m

angi

um

, M

ahoga

ny

Sri N

ugr

oho, et

al. (2

004)

4A

cac

ia c

atechu, etc

.R

oya

l Thai

Gove

rnm

ent

and

US. A

gency

for

Inte

rnat

ional

Deve

lopm

ent

(1984

)

5Seconda

ry f

ore

st, fr

uit o

rchar

dC

oom

es

and

Burt

(20

01)

in G

lase

r et

al. (2

002)

6Saw

dust

mou

nd

kiln

Seconda

ry f

ore

st s

peci

es

The p

roje

ct

7A

cac

ia c

atechu, etc

.R

oya

l Thai

Gove

rnm

ent

and

US. A

gency

for

Inte

rnat

ional

Deve

lopm

ent

(1984

)

8Sin

gle

dru

m k

ilnSeconda

ry f

ore

st s

peci

es

The p

roje

ct

9Seconda

ry f

ore

st s

peci

es

The p

roje

ct

10A

cac

ia c

atechu, etc

.R

oya

l Thai

Gove

rnm

ent

and

US. A

gency

for

Inte

rnat

ional

Deve

lopm

ent

(1984

)

11M

ark

V k

ilnSeconda

ry f

ore

st s

peci

es

(Als

tonia

, A

rocar

pus,

etc

.)A

gus

(1982)

12A

cac

ia c

atechu, etc

.R

oya

l Thai

Gove

rnm

ent

and

US. A

gency

for

Inte

rnat

ional

Deve

lopm

ent

(1984

)

13Yos

him

ura

kiln

Acac

ia m

angi

um

, R

ubb

er

The p

roje

ct

14B

rick

kiln

Eucal

yptu

s, e

tc.

Sudr

adja

t an

d Sal

im (

1994)

15Seconda

ry f

ore

st s

peci

es

(Als

tonia

, A

rocar

pus,

etc

.)A

gus

(1982)

16M

angr

ove

Tju

tju e

t al

. (2

003)

17A

cac

ia m

angi

um

Tju

tju e

t al

. (2

003)

18B

rick

Bee

hiv

e k

ilnA

cac

ia c

atechu, etc

.R

oya

l Thai

Gove

rnm

ent

and

US. A

gency

for

Inte

rnat

ional

Deve

lopm

ent

(1984

)

19Fla

t ki

ln (sa

wdu

st)

Par

aserian

thes,

Mae

sopsi

s, e

tc.

The p

roje

t

43

Mangrove wood, however, is getting more difficult to obtain at the present.

(7) Carbon yield of flat kiln was still lower comparing with other types of kilns.

From these data, drum kiln or permanent kilns can be recommended if considering the efficiency of carbonization. drum kiln, however, can produce small amount of charcoal at once. Permanent kilns need skilled worker and higher costs for building kilns, and are less suitable for carbonizing small sized wood residues. It needs evenly sized wood material. Earth pit kiln still can maintain more than 30% carbon yield if charcoal makers were well-trained.

Photo 42 Mark V kiln (East Kalimantan) Photo by Agus (1982) Behind the kiln: Retort kiln.

Photo 43 Brick kiln in East Kalimantan Photo by Agus (1982)

44

V. Comparison of cost efficiency 1. Earth pit kiln and brick floor kiln

Table 10 shows the cost to produce charcoal by earth pit kiln (kiln volume = 4.5m3). Earth pit kiln merely uses materials which are available in the field, and only labor cost was considered here. Totally, Rp.70,000 is necessary if one worker make one kiln. In the case of smaller kiln, digging earth pit and loading wood material can finish in one day and total costs can be reduced to Rp.60,000.

Fig. 8 shows the relationship between kiln volume (volume of wood material) and weight of produced charcoal. As already indicated in Fig. 6, efficiency of carbonization of larger sized kiln (more than 8m3) declined drastically and in this figure, such kiln was excluded. Estimation using the equation in the figure indicates that 3m3 kiln can produce 189kg charcoal and 4m3 kiln can produce 284kg charcoal. Table 10 Costs for charcoal production by earth pit kiln

Item Amount Price (Rp.) Digging earth pit 1 person*day 15,000 Loading wood material 4.5m3 15,000 Watching kiln (ignition to closing kiln)

2 days 30,000

Unloading charcoal 1 person*0.5day 10,000 Total 70,000

Fig. 8 Relationship between kiln volume and weight of produced charcoal Note: Earth pit kiln at Maribaya and Ngasuh. Large sized kiln (9.24m3) at Maribaya was excluded.

45

Table 11 demonstrates one example of working schedule. Considering period of cooling process, one worker can make two kilns. This schedule was made under the assumption that whole carbonization process (including cooling down) can finish in one week (7 days). In this case, first charcoal can be obtained in 9th day. After that, every 4 days charcoal can be unloaded (Table 12). Table 12 is the cost estimation under this condition. For one month (29 days), one worker can produce 1.70 ton charcoal and 1.28 ton of carbon. The costs were Rp.255,282(US$29.65)/t-Charcoal and Rp.338,929(US$39.36)/t-Carbon. After about 2 months (61 days), 4.00ton charcoal and 2.99ton carbon can be produced at the cost of Rp.230,131(US$26.73)/t and Rp.305,537(US$35.49)/t respectively.

Table 11 One example of working schedule for one worker (Earth pit kiln) Day 1st kiln 2nd kiln

1 Digging pit 2 Loading wood material, Ignition 3 Watching 4 Watching Digging pit 5 Watching, Closing kiln Digging pit, Loading wood material 6 Loading wood material, Ignition 7 Watching 8 Watching 9 Unloading charcoal Watching, Closing kiln 10 Loading wood material, Ignition 11 Watching 12 Watching 13 Watching, Closing kiln Unloading charcoal 14 Loading wood material, Ignition 15 Watching 16 Watching 17 Unloading charcoal Watching, Closing kiln

46

Table 12 Calculation of cost per charcoal and carbon (one worker) Accumulated amount Average cost (Rp.) Charcoal

production (unloading)

Days Total wage (Rp.)

Charcoal(kg) 1)

Carbon (kg) 2) Cost/t-Charcoal Cost/t-Carbon

1st 9 135,000 284 213.91 475,352 631,110 2nd 13 195,000 568 427.82 343,310 455,802 3rd 17 255,000 852 641.73 299,296 397,366 4th 21 315,000 1136 855.64 277,289 368,148 5th 25 375,000 1420 1069.54 264,085 350,617 6th 29 435,000 1704 1283.45 255,282 338,929 7th 33 495,000 1988 1497.36 248,994 330,581 8th 37 555,000 2272 1711.27 244,278 324,320 9th 41 615,000 2556 1925.18 240,610 319,451

10th 45 675,000 2840 2139.09 237,676 315,555 14th 61 915,000 3976 2994.72 230,131 305,537

Notes: 1) One worker make 2 kilns (Size = 4m3) following the schedule indicated in Table 12. The kiln can

produce 284kg charcoal at once.

2) Percentage of pure carbon in charcoal (fresh weight) = 75.32% (Calculated from the data shown in Table 1. Average of earth pit kiln at Maribaya and Ngasuh).

Table 13 Costs for producing charcoal and carbon (per one worker, earth pit kiln) under different assumptions

Accumulated amount Average cost (Rp.) Labor wage Duration Charcoal

(kg) Carbon (kg) Cost per charcoal

Cost per carbon

29 days 1,704 1,238 340,736 451,906 Wage =Rp.20,000/person*day 61 days 3,986 2,995 306,841 407,383

29 days 1,704 1,238 425,469 564,882 Wage =Rp.25,000/person*day 61 days 3,986 2,995 383,551 509,229

Table 13 demonstrates average costs under different assumptions (different labor wage). Outside Java Island, labor costs are higher and Rp.15,000/person*day is not applicable. If wage is Rp.25,000/person*day, cost per ton carbon is Rp.509,229 (US$59.14) after 2 months’ operation.

One of other alternatives is buying produced charcoal from local people. During 2001 to 2002, local price of charcoal was Rp.5,000 (Sri Ngroho et al. (2004) stated that local price around Yogyakarta was also Rp.5,000). Average weight of charcoal per karung in Ngasuh was 10.64 kg (about this figure, explained later in Table 30). In such case, cost per ton carbon becomes Rp.617,104 (US$71.67).

PT. Perhutani sells fuel wood of Acacia mangium (stem and branches less than 10m in diameter) at the price of Rp.17,000/staple meter (0.75m3). One informant from a local brick factory near Leuwiliang town (See Fig.1, located between Bogor and Jasinga

47

town) bought 1 staple meter of fuel wood at the price of Rp.20,000. If wood material must be bought, local people never produce charcoal. PT. Perhutani gives some part of fuel wood to local people for free and they can make charcoal without considering costs for material.

Table 14 shows costs to produce charcoal by brick floor kiln (Rp.190,000, US$22.07). If carbonization efficiency is not improved using bricks, earth pit kiln is recommended because in the process of brick production, certain amount of carbon is emitted to the air.

According to the data obtained by interview at brick factory (Photo 44) located near Leuwiliang town (See Fig. 1, located between Bogor and Jasinga town), to produce 20,000 bricks, 15 staple meter (1 staple meter = 0.75 m3) of fuel wood is necessary. Oven dry weight of fuel wood stored beside the kiln was 148.21 kg/1 staple meter. To produce 20,000 bricks, 1,110kg of carbon was emitted (0.0555kg/brick). Production of 400 bricks equals to 22.2kg carbon emission. Table 14 Costs for charcoal production by brick floor kiln

Item Amount Price (Rp.) Brick 400 120,000 Digging pit and putting bricks 1person*1day 15,000 Loading wood material 1person*1day 15,000 Watching kiln (ignition to closing kiln) 1person*2day 30,000 Unloading charcoal 1person*half day 10,000

Total 190,000

Photo 44 A kiln for producing bricks. Comparing with other factories around experimental sites in West Java, this kiln is larger size.

48

3. Earth pit kiln at sawmill

At a sawmill near Jasinga town, slabs were carbonized by earth pit kiln (Photo 14). Table 15 is the result of survey conducted at the sawmill. This is only rough estimation based on data from interview. Actual data of charcoal yield (30.41%) and carbon yield (43.78%) could be lower than estimation in Table 16.

One charcoal maker was working with 2 kilns. Carbonization finishes 10 days after ignition, and unloading of charcoal is taken place twice within 10 days. 300 karung of charcoal (produced in 10 days) are sold at the price of Rp.1,650,000 (US$191.64). After selling charcoal, owner of the sawmill took two thirds of the gains (Rp.1,100,000, US$127.76), and the charcoal maker took the rest (Rp.550,000, US$63.88). Monthly income of the charcoal makers can amount to Rp.1,650,000.

Produced carbon amounts to 2.22t/10days. Regarding Rp.1,650,000 as production cost (if the charcoal is not sold and stored for carbon sequestration), average cost per ton carbon is Rp.247,748 (US$28.77).

Table 15 Information of earth pit kiln at a sawmill (one kiln) Kiln volume 25.65 m3 Dry weight of wood material (slab)

5,070 kg 1)

Produced charcoal (kg) 1,542 kg 2)

(10.28kg/karung x 150karung) Charcoal yield 30.41 % Charcoal analysis

Moisture content Fixed carbon content

2.81 % 74.06 %

Carbon yield 43.78 % Carbonization time (including cooling down)

10 days

Price of charcoal Rp. 5,500/karung Notes:

1) Sample of slabs (0.71m3) was weighed. Dry weight of the sample was 140.84kg. Using this data, total dry weight of wood material was estimated from kiln volume (140.84 kg x 15.65m3 / 0.71m3).

2) 5 karung of produced of charcoal were weighed. The average was 10.28kg/karung. The respondent (charcoal maker at the sawmill) stated that 150 karung of charcoal is produced

4. Drum kiln

Table 16 shows costs for making single drum kiln. The cost was Rp.109,500/kiln (US$12.72).

49

Table 16 Costs for making single drum kiln

Item Amount Price (Rp.) Oil drum 1 75,000 Galvanized iron sheet 1.5 m 7,500 Rivet 20 2,000 Worker 1person*day 25,000

Total 109,500

Drum kiln (air inlets at the bottom of kiln) can produce 7.88kg charcoal at once (Table 5). From the experience in the field, it is assumed that one worker was able to operate 5 drum kilns. According to Okimori et al. (2003), drum kilns can use at least 100 times. After 100 times carbonization, 5 drum kilns can produce 3.9t charcoal or 3.7t carbon (Table 17). Cost per ton-carbon was Rp.656,806(US$76.28)/t-Carbon. This estimation was made under the assumption that labor wage is Rp.15,000/person*day. Cost/10kg-charcoal was Rp.5,250, and this is about the same as local price of charcoal.

Table 18 indicates cost per ton charcoal and carbon when labor wages are higher than the assumption of Table 17. Table 17 Costs for producing charcoal and carbon (per one worker, 5 single drum kilns)

Accumulated amount Average cost Day

Cost (Rp.) Charcoal (kg) 1) Carbon (kg) 2) Cost/t-Charcoal

(Rp.) Cost/t-Carbon

(Rp.) 1 562,500 - - - - 2 577,500 39 31 14,657,360 18,340,041 3 592,500 79 63 7,519,036 9,408,203 4 607,500 118 94 5,139,594 6,430,923 5 622,500 158 126 3,949,873 4,942,284

10 697,500 355 283 1,967,005 2,461,218 30 997,500 1,143 913 873,009 1,092,354 60 1,447,500 2,325 1,858 622,688 779,139

100 2,047,500 3,901 3,117 524,919 656,806 Notes:

1) One kiln can produce 7.88kg at once. 2) Percentage of pure carbon in charcoal (fresh weight) = 79.92% (Calculated from the data shown in

Table 5).

50

Table 18 Costs for producing charcoal and carbon (per one worker, 5 single drum kilns) under different assumptions

Wages Cost (Rp.) Produced charcoal

(kg)

Carbon in charcoal

(kg)

Cost/t-Charcoal (Rp.)

Cost/t-Carbon (Rp.)

(1) Rp.30,000/person*day (2) Rp. 20,000/person*day 2,572,500 3,901 3,117 659,514 825,218

(1) Rp. 35,000/person*day (2) Rp. 25,000/person*day 3,097,500 3,901 3,117 794,109 993,629

Notes: (1) Wages for making drum kilns (2) Wages for producing charcoal

Table 19 Costs for making double drum kiln

Item Amount Price (Rp.) Oil drum 4 260,000 Galvanized iron sheet 1 m 15,000 Rivet 30 3,000 Worker 1person*10day 250,000

Total 528,000

Costs for making double drum kiln are indicated in Table 19 (Rp.528,000, US$61.32). The total costs were nearly 5 times as much as those of single drum kiln. The amount of produced charcoal, however, was 10.5kg (Table 5). This method was not economically viable. 5. Yoshimura kiln

Table 20 and 21 indicates costs for building Yoshimura kiln (5m3 and 3m3). The difference between 5m3 and 3m3 kilns was Rp.656,878.

Table 22 shows the labor costs for producing charcoal. If two kilns are operated simultaneously, 2 workers can operate 2 kilns after ignition. Under the assumption made in Table 23, average cost per charcoal and carbon are calculated (Table 24). Even after carbonization is repeated 10 times (100 days), average cost per ton is still more than 3 million Rupiah (Rp.3,250,075/t-Carbon, US$377.48).

51

Table 20 Costs for building Yoshimura kiln (5m3) Item Quantity Price per unit (Rp.) Total (Rp.)

<Kiln> Bricks for kiln wall 1,814 600/brick 1,088,400 Bricks to uphold chimney 600 600/brick 360,000

Chimney 1 150,000/unit 150,000 Iron grating for kiln floor 4,91m2 100,000/ m2 490,874

Roof of the kiln 5,15m2 140,000/ m2 721,552 Transportation costs (grating and kiln cover) 1 trip 250,000/trip 250,000

Cement 2sacks 28,500/sack 57,000 <Hovel>

Pole (8/8) for hovel 9 25,000 225,000 Bar (9/9) for hovel 9 27,000 243,000 Beam (5/7) 26 8,000 208,000 Galvanized iron sheet 39 sheets 17,000/sheet 663,000 Palm leaves 150 sheets 500/sheet 75,000 Nail 1 packet 38,000/packet 38,000

<Wages>

Wages for workers 3 workers (18 days) 20,000/person*day 1,080,000

Total 5,649,826 Table 21 Costs for building Yoshimura kiln (3m3)

Item Quantity Price per unit (Rp.) Total (Rp.) <Kiln>

Bricks for kiln wall 1,451 600/brick 870,600 Bricks to uphold chimney 600 600/brick 360,000

Chimney 1 150,000/unit 150,000 Iron grating for kiln floor 3.14 m2 100,000/m2 314,159

Roof of the kiln 3.28 m2 140,000/m2 459,189 Transportation costs (grating and kiln cover) 1 trip 250,000/trip 250,000

Cement 2 sacks 28,500/sack 57,000 <Hovel>

Pole (8/8) for hovel 9 25,000 225,000 Bar (9/9) for hovel 9 27,000 243,000 Beam (5/7) 26 8,000 208,000 Galvanized iron sheet 39 sheets 17,000/sheet 663,000 Palm leaves 150 sheets 500/sheet 75,000 Nail 1 packet 38,000/packet 38,000

<Wages> (3,912,948)

Wages for workers 3 workers (18 days) 20,000/person*day 1,080,000

Total 4,992,948

52

Table 22 Costs for loading wood material and vigilance (watching)

For loading wood material Watching Trial

Workers x days Wages Workers x days Wages Total wages

Acacia (5m3) 6 workers x 3 days Rp.450,000 2 workers x 4 days Rp.200,000 Rp.650,000Hevea (5m3) 6 workers x 3 days Rp.450,000 2 workers x 5 days Rp.250,000 Rp.700,000Vitex (3m3) 4 workers x 3 days Rp.300,000 2 workers x 4 days Rp.200,000 Rp.500,000Bellucia (3m3) 4 workers x 3 days Rp.300,000 2 workers x 3 days Rp.150,000 Rp.450,000Note: Wages for labor = Rp.25,000/worker*day Table 23 Assumptions for analysis (2 Yoshimura kilns: 5m3 x 2)

Item Amount Price (Rp.) Costs to build a kiln 2 kilns, Rp.5,649,826/kiln 11,299,652 Wages for loading wood material

6 workers x 3 days, Rp.25,000/person*day

450,000

Watching 2 workers x 4 days 200,000 Unloading charcoal 6 workers x 1 day 150,000 Carbonization time (including cooling down)

7 days -

Produced charcoal 769kg (429kg+347kg) 1) - Percentage of carbon in (fresh weight of) charcoal

77.22% 2) -

Notes: 1) 2) Average of data from No.1 and No.2 in Table 7. Table 24 Costs for producing charcoal and carbon (Yoshimura kiln)

Accumulated amount Average cost Day

Cost (Rp.) Charcoal (kg) Carbon (kg) Cost/t-Charcoal

(Rp.) Cost/t-Carbon

(Rp.) 10 12,099,652 769 594 - - 20 12,899,652 1,538 1,188 8,387,290 10,861,551 30 13,699,652 2,307 1,781 5,938,297 7,690,103 40 14,499,652 3,076 2,375 4,713,801 6,104,378 50 15,299,652 3,845 2,969 3,979,103 5,152,944

100 19,299,652 7,690 5,938 2,509,708 3,250,075 6. Flat kiln

Table 25 shows costs for building a flat kiln. Total cost was Rp.6,146,500 (US$713.88). As mentioned earlier, producing one piece of brick emits 0.0555kg carbon. This means that 222kg carbon was emitted by production of 4,000 pieces of bricks.

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Emission factor for cement production in Japan was 417kgCO2/t (in the year of 2000, equivalent to 113.73kgC/t, 0.11373kgC/kg. Ministry of Environment). Using this figure, production of 15 sacks of cement (750kg cement) emitted 85.3kg carbon. Possibly, emission from cement production per kg in Indonesia is larger than that in Japan.

Under the assumption indicated in Table 26, average costs for producing charcoal and carbon were calculated (Table 27). In this table, emission by brick and cement production is not included. Table 25 Costs for building a flat kiln

Item Amount Price (Rp.) Galvanized iron sheet 34 sheet 1,088,000 Scantling 1,336,000 Nail 6kg 45,000 Cement 15 sacks 420,000 Sand 2.5m3 437,500 Sieve (For sieving sand) 10,000 Bricks 4,000 1,600,000 Iron pipe for the chimney (Diameter: 6 inch) 6m 625,000

Wages of workers Rp.35,0001) x 11 person*day

+ Rp.25,0002) x 8 person*day

585,000

Total 6,146,500 Note: The size and structure of the kiln is indicated in Fig.2. Costs for modification was not included.

1) Wages for skilled worker (3 workers) 2) Wages for non-skilled worker (2 workers)

Table 26 Assumptions for analysis

Item Amount Cost for building a kiln Rp.6,146,500

Carbonization time 3 days Charcoal produced at one time

carbonization 0.255 t

Percentage of carbon in (fresh weight of) charcoal

69.55%

Numbers of workers employed 2 workers Wages of workers Rp.15,000/person*day

1) Data obtained in the 2nd trial (See Table 8)

According to Table 27, after 60days, 5.10ton charcoal and 3.55ton carbon are produced at the average cost of Rp.1,558,177(US$180.97)/t-Charcoal and

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Rp.2,240,312(US$260.20)/t-Carbon respectively. If considering the carbon emission from brick and cement production mentioned earlier, the average cost per ton carbon becomes Rp.2,452,813 (US$284.88) (1.10% Increase).

Table 28 shows cost estimation under the different assumptions. As mentioned earlier, Rp.15,000/person*day is too low in areas near large cities or outside Java Island. Table 27 Costs for producing charcoal and carbon (Flat kiln)

Accumulated amount Average cost Day

Cost (Rp.) Charcoal (kg) Carbon (kg) Cost/t-Charcoal

(Rp.) Cost/t-Carbon

(Rp.) 3 6,236,500 255 177 24,456,863 35,164,432 6 6,326,500 510 355 12,404,902 17,835,948 9 6,416,500 765 532 8,387,582 12,059,787

12 6,506,500 1020 709 6,378,922 9,171,706 30 7,046,500 2550 1774 2,763,333 3,973,161 60 7,946,500 5100 3547 1,558,137 2,240,312

Table 28 Costs for producing charcoal and carbon under different assumptions (flat kiln)

Accumulated amount Average cost (Rp.) Labor wage Duration Charcoal

(kg) Carbon (kg) 1)

Cost per charcoal

Cost per carbon

30 days 2550 1774 2,880,980 4,142,315Wage =Rp.20,000/person*day 60 days 5100 3547 1,675,784 2,409,467

30 days 2550 1774 2,998,627 4,311,470Wage =Rp.25,000/person*day 60 days 5100 3547 1,793,431 2,578,622

30 days 2550 1774 2,874,534 4,141,278Wage = Rp.600,000/person*month 2) 60 days 5100 3547 1,669,338 2,404,978Notes:

1) Emission by brick and cement production were not considered here. 2) Refer to Gustan Pari et al. (2004).

6. Comparison of costs for producing charcoal and carbon

It is apparent that earth pit kiln can produce charcoal and carbon at the lowest costs. Considering carbonization efficiency, however, oil drum kiln still can utilized for carbon sequestration project. The average cost after 100 times carbonization was still Rp.656,000 (US$76.28; Costs for collecting wood material are not included.) and much lower than permanent kilns. This method can be recommended for small to middle scale charcoal production. In large scale production, many drums are utilized, and after 100 times carbonization, will be wastes. The drums should be utilized for other purposes to avoid environmental degradation.

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Costs for earth pit kiln at sawmill was the lowest (US$28.77). It is because it can produce large amount of charcoal at once. It does not need to consider transportation cost of wood material as shown in the case of sawmill near Jasinga town.

If the scale and carbon efficiency of charcoal production by earth pit (in the field), it can produce charcoal and carbon at lower price. The trials to enlarge kilns showed that it was difficult to maintain the same efficiency with small kiln because local people were not familiar with large kiln. There is, however, possibility that after many trials or trainings, local people can produce charcoal using large kilns at higher efficiency.

Permanent kilns can produce larger amount of charcoal at once. The costs per produced carbon were much higher than those of earth pit and drum kiln. Permanent kilns need evenly sized material, and if materials with higher specific gravity are utilized as raw material, they can produce higher price of charcoal. Wood residues, however, are usually uneven sized, and it is difficult to obtain raw material with good quality (especially high specific gravity) recently.

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VI. Evaluation of viability of charcoal production for CDM projects 1. Carbonization of wood material from shrubs or secondary forests

1-a. Total amount of charcoal and carbon produced in West Java experimental sties

Table 29 shows total aboveground biomass in three locations. At Maribaya, some

area had been burned for rice cultivation one year before the measurement and small trees and undergrowth dominated the area. Other than slash and burn, this area was utilized by local people as source of fuel and material for charcoal making. Fig. 9 shows aboveground biomass of fallow lands in East Kalimantan. Comparing with this figure, vegetation in Maribaya is equivalent to 1 year-old stand, Ngasuh is about 7 year-old stand and Cianten is about 4 to 5 year-old stand. Table 29 Biomass amount of three locations in West Java

Location Total aboveground biomass (t/ha) 1)

Wood material: Stems, branches and stumps of

trees (t/ha) Percentage (%)

Maribaya 2) 12.36 5.24 (4.47) 42.39 (36.17) Ngasuh 40.94 36.62 89.45 Cianten 29.57 25.28 85.49

Notes: 1) Average of 20 plots (size of plot = 10m x 10m) 2) Figures in parentheses indicate amount of wood material excluding branches.

Fig. 9 Aboveground biomass of fallow land (East Kalimantan) Data source: Kojima et al. (1997), Morikawa (2001) and data from this project (at Maribaya)

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In Ngasuh and Cianten, no effects by slash and burn by local people. Larger sized

trees had been often extracted for pulp, sawn wood, and other purposes. Photos 45 to 47 are vegetations at Maribaya, Ngasuh and Cianten.

Photo 45 Shrubs in Maribaya (in the year of 2001)

Photo 46 Secondary forest in Ngasuh (in the year of 2001)

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Photo 47 Secondary forest in Cianten (in the year of 2001)

Table 30 shows total amount of produced charcoal in each location. Karung is Indonesian language which means large sized sack. Usually, charcoal is stored in karung and transported and sold. Weight of charcoal per karung seems to depend on wood density of materials indicated in Table 3.

Amount of carbon stored in charcoal at three sites are indicated in Table 31. At Maribaya, wood material was collected from the whole slashed area. At other two sites, not all wood material was collected. Table 30 Total amount of produced charcoal

Location Area (ha) Total amount of

produced charcoal (karung)

Weight of charcoal per karung (kg)

Number of samples1)

Total amount of produced charcoal

(kg) Maribaya 4.02 179 13.56 6 2,427.24 Ngasuh 4.08 850 10.64 54 9,044.00 Cianten 3.76 636 11.29 25 7,180.44

Note: 1) Number of karung with charcoal weighed and recorded. Table 31 Amount of carbon stored in charcoal

Amount of produced charcoalLocation Area

(ha)

Amount of wood

material (t/ha) (total, t) (t/ha)

Charcoal yield (%)

Amount of carbon

stored in charcoal (t/ha) 1)

Percentage of carbon stored in charcoal

Maribaya 2) 4.02 5.24

(4.47) 2.43 0.60

11.52 (13.51)

0.48 18.44

(21.61) Ngasuh 4.08 36.62 9.04 2.22 6.05 1.77 9.69 Cianten 3.76 25.28 7.18 1.91 7.55 1.53 12.09

Notes: 1) Calculated under the assumption that percentage of carbon inside charcoal is 80%. 2) Figures in parentheses: amount of wood material excluding branches.

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This low percentage of carbon storage in Maribaya is assumed to come from:

(1) In Maribaya, small sized branches and twigs dominated the area (See Photo 45). (2) In the field, wood material was collected manually, and possibly, some materials

were not collected and left on the ground. (3) Shrubs were cut not from the ground level. Stumps near the ground were still left

in the field. These facts demonstrated that, in the field, because of several factors, it was difficult to utilized all wood residues and achieve high carbon yield.

At the Ngasuh experimental site, if the wood material was fully carbonized, 3.66t/ha (Carbon yield = 20%) or 5.49t/ha (30%) of carbon can be produced. At the Cianten, the amount can be 2.53t/ha (Carbon yield = 20%) or 3.79t/ha (30%).

Table 32 shows the cost for collecting wood material. Data was obtained from field trials in West Java. Wood material was collected all manually. No vehicle was used. After clear-cutting the shrubs or secondary forests, wood material was scattered in the area. The cost in Maribaya was higher than other site because of difficulty to find proper size of wood for charcoal production. In shrubs of Maribaya, small trees (diameter at breast height < 2cm) dominated the vegetation. In the case of Ngasuh and Cianten, costs for collecting wood material can be Rp.5,000 to Rp.6,250 per m3. Cianten is steep-slope area and the costs became higher than Ngasuh (slope is more gentle).

Average of three sites shows that volume of material collected by one person*one day was 2.05m3. Cost to collect 1m3 was Rp.10,417 (US$1.20; under the rate in 14/4/2004. 1US$=Rp.8,610). If labor wage is Rp.20,000/person*day, the cost becomes Rp.13,889 (US$1.61 under the same exchange rate). When the wage is Rp.25,000/person*day, the cost is Rp.17,361 (US$2.02). Table 32 Costs for collecting wood material

Location Distance Number

of workers

Working hours

Volume of material collected

(m3)

Wage (Rp./person

*day)

Volume of material /

person * day

Person*day / volume of material

Wage per volume

(Rp./ m3)

Maribaya 50 to 300 meter 4 8 3 15,000 0.75 1.33 20,000

Ngasuh 50 to 300 meter 2 8 6 15,000 3.00 0.33 5,000

Cianten 300 meter 2 5 3 15,000 2.40 1) 0.42 2) 6,250 3)

Average 2.05 0.69 10,417 Notes: 1) 2) 3) Recalculated: Working hours = 8 hours Volume of material collected = 4.8 m3/2 workers.

Costs for collecting wood material can vary from place to place. In large scale plantation forests, trucks and other vehicles can be utilized for transportation. Even in such case, collecting wood material from the field to the road side is usually conducted

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manually.

1-b. Carbonizing wood material from shrubs or secondary forests

In the above case, several types and various sizes of kilns were utilized for charcoal production. One worker worked with one kiln and carbonization and cost efficiency became lower.

Under the assumption indicated in Fig. 8, Table 11 and Table 32, cost per ton carbon is calculated (Table 33). In this table, it is assumed that not all wood material is utilized because of following reasons:

(1) Some of stems and branches are left in the field to reduce soil erosion. (2) Small twigs (for example, less than 2cm diameter) are not suitable for charcoal

production. (3) Some amount of wood could be utilized as fuel wood.

Table 33 Estimation of carbon fixation potential and the costs Labor cost (Rp.) 6)

Location Amount of

wood material (t/ha) 1)

Volume of wood

material (m3) 2)

Kiln volume (m3) 3)

Number of kiln

Produced charcoal (t/ha) 4)

Weight of carbon in charcoal (t/ha) 5)

Charcoal production

Collection of wood

material 7)

Cost per ton carbon

Rp. /t (US$/t) 36.62 (total)

18.31 (1/2) 46.92 71.01 17 4.92 3.71 1,170,000 355,040 411,178 (47.76)

Ngasuh

24.41 (2/3) 62.55 94.68 23 6.79 5.11 1,530,000 473,387 391,906 (45.52)

25.28 (total)

12.64 (1/2) 30.43 46.05 11 3.32 2.50 810,000 287,843 439,150 (51.00)

Cianten

16.85 (1/3) 40.57 61.41 15 4.39 3.31 1,050,000 383,791 433,200 (50.31)

Notes: 1) (Total)=Stem weight + Branch weight + Stump weight, (1/2)=half of total amount of wood material

is utilized, (2/3)=two thirds of wood material is utilized. 2) Wood density=390.28kg/m3 in Ngasuh, 415.40kg/m3 in Cianten (Table 3). 3) Volume of wood material / Kiln volume =66.07% (Table 3). 4) 4m3 kiln can produce 284kg charcoal. In the last kiln, the volume becomes more than 4m3. Weight of

produced charcoal was calculated using formula shown in Fig. 8. 5) Percentage of pure carbon in charcoal (fresh weight) =75.32% (Calculated from the data shown in

Table 1) Average of earth pit kiln at Maribaya and Ngasuh. 6) 2 workers work with 4 kilns following the schedule shown in Table 11. Labor wage

=Rp.15,000/person*day. 7) Data of Table 32 were used for the calculation.

According to the table, the costs were US$45 to 51/t-Carbon. If charcoal makers,

however, are not trained well, weight of produced charcoal becomes lower. Specific

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gravity of wood material also affects weight of produced charcoal. If specific gravity is low, the figures in Table 33 become lower.

Labor cost was calculated under the assumption that labor wage is Rp.15,000/person*day. If the labor wage is Rp.25,000/person*day, the costs become as Table 34.

As mentioned in the last chapter, if produced charcoal was bought at the price of Rp.5,000/karung, cost per ton carbon becomes Rp.617,104 (US$71.67). In such case, charcoal production must be watched carefully to prevent charcoal makers from taking wood material outside the boundary of project area. Table 34 Cost per ton carbon: in the case that labor wage is Rp.25,000/person*day

Location Rp./t-Carbon (US$) 1/2 685,289 (79.59)

Ngasuh 2/3 653,170 (75.86) 1/2 731,923 (85.01)

Cianten 2/3 722,007 (83.86)

In the case of drum kiln, total costs will be higher as indicated in the last chapter. To improve the cost efficiency, size of earth pit kiln must be enlarged without

reducing charcoal yield. This, however, needs training because large-sized earth pit kiln is not common in Indonesia.

Baselines can be as follows: (1) Slash-and-burn for agriculture (shifting cultivation) (2) Slash-and-burn for conversion of vegetation into tree plantations. If the baseline is slash-and-burn, assuming all carbon emitted to the air (actually,

small amount of carbon still remains on the field in the form of charcoal in the case of shifting cultivation), total amount of sequestered carbon can be as shown in Table 33.

In the densely populated area, there is competition with demand for fuel wood. In such case, leakage effects must be considered. For example, in Java Island, biomass from shrubs or secondary forests is fully utilized and there seems to be no wood residues. This type of project can be implemented only in less-densely populated area where demand for fuel wood is smaller.

Just buying charcoal in the market and storing the charcoal cannot be carbon sequestration project. As mentioned earlier, in the process of carbonization, 60 to 70% of carbon was disappeared to the air (or in the form of volatile matter). CDM project can implemented in where the baseline is clear.

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2. Wood residues from plantation forests (Acacia mangium)

In West Java, Acacia mangium wood was used for furniture, not for pulp. 2m logs with above-10cm diameter (average diameter of tip and bud) are sold. Residues are sold as fuel wood or given to village people for free. Local people often produce charcoal from the given wood residue. Table 35 shows the amount of total aboveground biomass and wood residue and amount of pure carbon stored in charcoal. Data from West Java indicate that after 8 years, the amount of wood residue did not increase. Low stand density in West Java was because of thinning operations. According to the data shown in the table, amount of wood residue are proportional to stand density. Table 35 Amount of wood residue (oven dry weight) and pure carbon stored in produced charcoal (logs of above 10cm diameter are extracted)

Wood residue: Stem(<10cm) and branches Location

Stand density

(trees/ha)

Total aboveground biomass (t/ha) Amount

(t/ha) 1) Percentage

(%) 2) PT. Perhutani, West Java, 10 year-old stand 225 84.48 12.06 14.27

PT. Perhutani, West Java, 8 year-old stand 283 53.48 14.63 27.36

MHP, South Sumatra, 9 year-old stand (Hardiyanto,et al., 2000)

1,250 189.50 3) 46.60 4) 24.59

Notes: 1) Biomass amount was estimated using allometric equations (Biomass=a*(DBH2*Height)b;

a,b=constant). 2) Percentage (%) = 100 * (weight of wood residue) / (weight of total aboveground biomass) 3) Litter (16.8t/ha), standing dead wood (5.8t/ha), understorey (1.9t/ha) were excluded. 4) Tree barks of stem (14.2t/ha) were excluded.

Except Java Island, most of Acacia mangium wood is utilized as pulp. For pulp wood, 2m logs with above-8cm diameter are extracted. According to data from Hardiyanto et al., (in press) in Okimori et al. (2003), 56.4t/ha (oven dry weight) of wood residue can be obtained from Acacia mangium plantation (total aboveground biomass = 241.1t/ha) in PT. MHP. This figure seems very high compared with other researches. In PT. MHP’s plantations, 10,750ha is cleaned annually, and the annual sum of forests residue is estimated to be 606,300t/ha (oven dry weight) (Okimori et al., 2003).

In Table 36, data from PT. MHP and West Java were compared. According to the table, it was shown that if stand density and carbonization efficiency are high, about 10t/ha of pure carbon can be extracted from wood residue.

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Table 36 Amount of wood residue (oven dry weight) and pure carbon stored in produced charcoal (logs of above 8cm diameter are extracted)

Wood residue: Stem(<8cm) and branches Location

Stand density

(trees/ha)

Total aboveground

biomass (t/ha) Amount

(t/ha) 1) Percentage

(%) 2) PT. Perhutani, West Java, 10 year-old stand

225 84.48 11.14 13.18

PT. Perhutani, West Java, 8 year-old stand

283 53.48 13.16 24.60

MHP, South Sumatra, (Stand age: n.a.) (Hardiyanto,et al., in press)

n.a. 241.10 3) 56.40 23.39

Notes: 1) Biomass amount was estimated using allometric equations (Biomass=a*(DBH2*Height)b;

a,b=constant). 2) Percentage (%) = 100 * (weight of wood residue) / (weight of total aboveground biomass) 3) It is not mentioned whether biomass and necromass of litter, standing dead wood, understorey were

excluded. Comparing with data from Hardiyanto, et al. (2000), possibly those were included. If so, percentage of wood residue (23.39%) becomes higher.

Under the same condition of Table 33, produced carbon and cost per ton carbon was calculated (Table 37). Figures shown in Table 35 were utilized. Cost per ton carbon was almost the same as that in Table 33. If labor wage is Rp.25,000/person*day, costs per ton carbon become the figures shown in Table 38. As mentioned earlier, one alternative is to buy produced charcoal. It can possibly reduce the costs.

At the beginning of 1999, Perum Perhutani had 6,735ha planted area of Acacia mangium (Statistics of Timber Estate 1999). During the year of 1999, 236ha was cut and replanted (reforested). Assuming that 1.78t-Carbon/ha can be produced, 420ton carbon can be produced in one year.

As mentioned earlier, however, large portion of the residues were sold as fuel wood. The price was Rp.17,000/Staple meter (Price of the year 2004. 1 staple meter = 0.75m3). In densely populated Java Island, those residues are very important for fuel wood and it is not possible to utilize them as raw material for charcoal production. Leakage will be large if charcoal production was implemented as a CDM project.

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Table 37 Estimation of carbon fixation potential and the costs (Acacia mangium plantations)

Labor cost (Rp.) 6)

Location Amount of

wood material (t/ha) 1)

Volume of wood

material (m3) 2)

Kiln volume (m3) 3)

Number of kiln

Produced charcoal (t/ha) 4)

Weight of carbon in charcoal (t/ha) 5)

Charcoal production

Collection of wood

material 7)

Cost per ton carbon Rp. /t

(US$/t)

14.63 (Total)

7.32 (1/2) 16.31 24.69 6 1.77 1.33 510,000 123,435475,172 (55.19)

Perhutani (8 year)

9.75 (2/3) 21.75 32.92 8 2.36 1.78 630,000 164,579

447,061 (51.92)

46.60 (Total)

23.30 (1/2) 51.01 77.21 19 5.51 4.15 1,290,000 386,066403,766 (46.89)

MHP (9 year)

31.07 (2/3) 68.02 102.95 25 7.38 5.56 1,650,000 514,755389,411 (45.23)

Notes: 1) (Total)=Stem weight + Branch weight + Stump weight, (1/2)=half of total amount of wood material

is utilized, (2/3)=two thirds of wood material is utilized. 2) Wood density=448.48kg/m3 in 8 year-old stand, 456.73kg/m3 in 9 year-old stand (average of 8 and 10

year-old stands. Data was obtained from the survey in Acacia mangium plantations of PT. Perhutani, BKPH Parungpanjang.).

3) Volume of wood material / Kiln volume =66.07% (Table 3). 4) 4m3 kiln can produce 284kg charcoal. In the last kiln, the volume becomes more than 4m3. Weight of

produced charcoal was calculated using formula shown in Fig. 8. 5) Percentage of pure carbon in charcoal (fresh weight) =75.32% (Calculated from the data shown in

Table 1) Average of earth pit kiln at Maribaya and Ngasuh. 6) 2 workers work with 4 kilns following the schedule shown in Table 11. Labor wage

=Rp.15,000/person*day. 7) Data of Table 32 were used for the calculation.

Table 38 Cost per ton carbon: in the case that labor wage is Rp.25,000/person*day

Location Rp./t-Carbon (US$) 1/2 791,947 (91.98) Perhutani

(8 year) 2/3 745,096 (86.54) 1/2 672,936 (78.16) MHP

(9 year) 2/3 649,012 (75.38)

In large scale Acacia mangium plantations, large amount of wood residues can be obtained. From pulp mill, huge amount of tree bark is unutilized. If combining the carbonization of those materials, the cost could be lower. Drum kilns and brick kiln (for carbonizing logging residues) and flat kilns (for carbonizing tree bark) are utilized.

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Estimation by Okimori et al. (2003) indicates that cost per ton carbon was about US$62/t-Carbon (US$17/t-CO2).

Humu pipe kiln (Okimori, et al. 2003) also can be recommended if the scale of plantation forests is large enough. To reduce the cost, kiln size should be enlarged. 3. Wood residue from sawmill

Table 37 shows sawn wood production in Indonesia and estimated amount of wood residues. This estimation was made under the assumption indicated by Martawijaya and Sutigno (1990) in Ng. Gintings and Han Roliadi (2004). Other data source stated that yield of sawn timber (percentage of sawn timber / wood log) is 45% (Kikata, 1996) and 20 to 30 percent of wood material becomes sawdust in sawmill operations (Kikata and Sri Nugroho, 1994). This supports the data shown by Martawijaya and Sutigno (1990). As shown in the table, in the year of 2000 (but until December), about 1.8 million m3 of sawdust was produced. Table 37 Amount of sawn wood production in Indonesia and estimated amount of wood residues

Estimated amount of wood residue (m3) Year

Sawn wood production

(m3) Sawdust Slab End trimming

Total residue

1994/1995 (April - March) 1,729,839 1,025,202 718,246 306,956 2,050,404 1995/1996 2,014,193 1,193,726 836,313 357,414 2,387,453 1996/1997 3,565,475 2,113,105 1,480,420 632,685 4,226,210 1997/1998 2,613,452 1,548,882 1,085,131 463,751 3,097,763 1998/1999 2,707,221 1,604,454 1,124,065 480,390 3,208,909 1999/2000 2,060,163 1,220,971 855,400 365,571 2,441,941

2000 (April - December) 3,020,864 1,790,337 1,254,292 536,045 3,580,674 Data source: Statistical year book of Indonesia 2001 and Forestry and estate crops statistics of Indonesia. Note: Amount of wood residue was estimated under the assumption as follows:

Percentage of sawmill waste is 54.24%: Sawdust (27.12%), slabs (19.00%) and end trimming (8.12%), data is from Martawijaya and Sutigno (1990) in Ng. Gintings and Han Roliadi (2004).

Statistical data of sawntimber production by province, however, indicates that sawn timber production was zero in West Java, Jakarta, Yogyakarta, Bali and East Timor (Forestry and estate crops statistics of Indonesia 1999/2000, Page 8). As mentioned earlier in this report, there are a lot of small scale sawmills in West Java. It is apparent that the data shown in Table 35 does not cover whole production in Indonesia. The total amount of sawdust seems to be larger than 1.8 million m3 in 2000.

According to Gusmalina, et al. (2002), in Jambi Province, there were 103 sawmills (latest information reporting 150 sawmills) and sawmill consumed 20m3 of wood logs per day (operating 24 hours/day), thereby generating waste as much as 3.0m3

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per day sawmill (in this case, percentage of sawdust/wood logs is higher). It is estimated that more than 100 thousand m3 of sawdust (3.0m3 x 103sawmills x 365day = 112,785m3/year) was produced in Jambi Province.

In the case of sawmills located near Jasinga town (Photo 3 and 14), from about 48m3 logs, 14.4m3 (36 karung x 100 liter/karung x 4 sawmills) of sawdust were being produced (Operating from 7:30 to 16:00). Some part of slabs was being utilized for making small wooden boxes and others became charcoal by earth pit method. Slabs were fully utilized and not sold as fuel wood. Sawdust, however, were unutilized as seen in Photo 3.

The kiln build by this project at Bogor can carbonized 154 karung at once. After filling sawdust into the kiln, sawdust was compacted. Sawdust from four sawmills can carbonized using three kilns (If kiln size is expanded, two kilns are enough). Assuming one karung contains 12 kg sawdust and moisture content of sawdust is 20%, oven dry weight of sawdust obtained from the 4 sawmills is 13,824kg. Assuming carbon yield is 20%, 138.24kg carbon can be obtained from 14.4m3 sawdust. If this figure is applied to data shown in Table 35, 17,187 ton carbon can be produced from 1,790,337 m3 sawdust.

As mentioned earlier, carbonization of slabs from sawmill was the most cost effective. The volume of slabs utilized as material for charcoal was 25.65m3/kiln. One worker can produce 2.22 ton carbon (3.08 ton charcoal) from 51.3m3 of slabs for 10 days. Table 35 shows that 1,254,292 m3 of slabs can be obtained from sawmills. From this amount, 54,279 ton carbon can be produced. Transportation costs of wood material were not necessary. As mentioned in the last chapter, cost per ton carbon was about US$30 (actually, it depends on costs for labor wages).

Training of workers, however, is necessary to achieve higher carbonization efficiency.

Baselines can be as follows:

(1) Slabs and sawdust are burned: all carbon will be emitted. (2) Slabs and sawdust are not burned and piled up or utilized for inning of sea or river

banks: Decomposition rates are not known. It seems that decomposition of wood in the water is slower than that on the forest floor because of fewer decomposers.

In the case (1), charcoal production at sawmills can be CDM projects. In the case (2), the viability as CDM project is not clear.

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VII. Conclusions 1. Factors which affect on carbon yield and cost efficiency

Carbon yield of charcoal production in Indonesia rarely exceeds 40%.

Carbonization efficiency heavily depends on skill of charcoal makers. Cost per produced charcoal and carbon by earth pit kiln was the lowest.

Carbonization efficiency, however, was lower than other types of kilns. Enlargement of kilns can improve cost efficiency (and probably carbonization efficiency). The trials by this project, however, demonstrated that local people in villages are usually not familiar with large sized kiln and carbonization efficiency reduced in large sized kiln (in the case of earth pit kiln). Training of charcoal makers is necessary to improve carbon and cost efficiency.

Permanent kiln can achieve higher carbon yield. However, costs were too high for carbon sequestration project (especially in the case of small scale projects). Carbonization and cost efficiency of drum kilns were relatively good. The amount of charcoal production by one kiln, however, was limited. 2. Viable project types for carbon sequestration

Charcoal production using wood residues from logging can be CDM projects. For implementation of the project, however, carbon price needs to be higher. In densely populated area such as Java Island, it seems difficult to implement such projects because charcoal production competes with demands for fuel wood. In such case, leakage will be large.

Charcoal production at sawmills (especially carbonization of slabs) has potentials for CDM projects. The viability, however, depends on the baselines. Well-trained charcoal makers are also necessary. Production of sawdust charcoal still needed higher costs. Enlargement of kilns is one way to reduce those costs.

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Acknowledgements Our special thanks go to

Dr. Makoto Ogawa and Yasuaki Okimori from KANSO, who supported us for providing idea, research methods and so on.

Mr. Minoru Sugai from Hokuetsu Shoji Co., who always gives us useful information including a design of flat kiln at an activated charcoal factory in Parungpanjang town.

Mr. Noriaki Seki from Kuji Bunka Nenryo, who gave us some idea regarding charcoal production methods.

Mr. Takayuki Furumoto from Hyonen Kogyo Co. who advised us about methods for charcoal analysis and kiln construction. He came to Indonesia twice as a short-term expert on charcoal production techniques and gave us important guidance for our project activities.

Mr. Rudijanta Utama, Mr. Donatus Rantan, Ms. Merry and other staffs from Yayasan Dian Tama, who supported us for carrying out project activities in West Kalimantan. We also would like to thank staffs of PT. Perhutani, BKPH Parunapanjang,

Leuwiliang and Jasinga. People living around the experimental sites in West Java who contributed to charcoal production.

Without their helping, this project could not be carried out.

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