of this document is subject to the conditions of the contract within the 7th Framework Programme, grant agreement no. 605357
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EXECUTIVE SUMMARY
The research project PHENOLIVE aimed at the production of valuable products from residues of olive oil industry. The present report contains the results of an experimental gasification test runs with exhausted olive pomace at TU WIEN. The test runs were executed to evaluate the potential of exhausted olive pomace as fuel for a dual fluidized bed gasification system. The experimental investigation of relevant gasification parameters was executed with a bed material mixture of olivine and calcite. The present report includes:
• a precise fuel characterization of exhausted olive pomace for the gasification test run, • a description of the executed feedstock pre-treatment steps (calcite addition, pelletizing), • a detailed description of all main plant parts and the measurement equipment of the novel dual
fluidized bed system at TU WIEN, • and the achieved experimental results with the novel 100 kW dual fluid gasification test plant
(temperatures, gas composition, important parameters, pressure profiles, etc.). The present report summarizes the collected data from the executed test runs and includes a short interpretation of the results.
2.1. FUEL PRE-TREATMENT AND FUEL ANALYSIS ............................................................................................................................. 6 2.1.1. Characterization of exhausted olive pomace (EOP) ........................................................................................ 6 2.1.2. Determination of necessary fuel treatment .................................................................................................... 8 2.1.3. Preparation of pre-treated EOP-pellets for gasification experiments ........................................................... 10
2.2. OPERATIONAL PARAMETERS AND SETUP OF THE DFB GASIFIER SYSTEM .................................................................... 12 2.2.1. Main operational parameters of the fluidized bed reactor system .............................................................. 12 2.2.2. Continuous “online” measurement equipment ............................................................................................. 18 2.2.3. Discontinuously measured product gas contents ......................................................................................... 20 2.2.4. IPSEpro-simulation – Mass and energy balance ........................................................................................... 22 2.2.5. General overview of the gasification test run with EOP ............................................................................... 23 2.2.6. Results of the gasification with EOP: Operation point 1 (OP1) ..................................................................... 24 2.2.7. Results of the gasification with EOP: Operation point 2 (OP2) ..................................................................... 29 2.2.8. Comparison of product gas composition of OP1 and OP2 ............................................................................ 32 2.2.9. Further planned variations of process parameters ....................................................................................... 32
3.1. CONCLUSION ................................................................................................................................................................ 33 3.2. OUTLOOK AND SCALE-UP POTENTIAL .......................................................................................................................... 33
4. LITERATURE ............................................................................................................................................................. 34
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1. INTRODUCTION
1.1. INITIAL SITUATION
The thermo-chemical conversion of biogenous feedstock is a promising option to advance the eco-friendly and efficient production of heat and power, as well as the generation of valuable products for the chemical industry based on renewable sources. Biomass is particularly relevant, as this feedstock constitutes the only carbon source available within the range of renewable resources. Fluidized bed processing is applied by preference for the gasification of various carbonic fuels, and therefore also for biomass. This technology intensely promotes the conversion of the solid feedstock into a valuable gas by an excellent gas-solid contact and heat transfer. The application of biomass derived product gas as fuel/reduction gas or precursor for various syntheses might increase the share of renewables in the industry in contrast to fossil fuels. Therefore, the dual fluidized bed (DFB) steam gasification system enables the generation of a nitrogen free product gas. The product gas yielded has a high heating value of typically 12 MJ/Nm³. The basic principle of the entire dual fluidized bed (DFB) gasification technology is shown in Figure 1.
Figure 1: Basic principle of the dual fluidized bed steam gasification technology
The dual fluidized bed concept is highly qualified for “scale-up”. The technical feasibility of this gasification technology has been proven in the early 2000’s with the combined heat and power plant (CHP) Güssing in Austria (see Figure 2). Further plants, based on the concept, went into operation in Oberwart/Austria (9 MWth), Senden/Germany (14 MWth) (Figure 3 – 4), Villach/Austria (15 MWth) and in Göteborg/Sweden (32 MWth).
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Source: TU Wien
Figure 2: 8 MW plant in Güssing, Austria
Source: TU Wien
Figure 3: 9 MW plant in Oberwart, Austria
Source: Maierhans F., Stadtwerke Ulm/Neu-Ulm
Figure 4: 14 MW plant in Senden/Neu-Ulm, Germany
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1.2. CHALLENGES AND RESEARCH TASK
Dual fluidized bed steam gasification technology has to meet new challenges. The system flexibility with regard to the application of different feedstock is a major issue of current experimental research. Beside the application of conventional wood as feedstock, it is aimed to enlarge the range of applicable fuels. Thus, the extension of the feedstock basis for the dual fluidized bed system promotes the flexibility in terms of economic advantages of the system. But from the gasification of alternative fuels typically higher tar contents in the product gas are present. Thus, a new design of a dual fluidized bed reactor system is available at TU Wien to investigate the inherent tar reduction in the gasification reactor.
Experiments with the alternative fuel type exhausted olive pomace (EOP) with a new 100 kW gasification pilot plant are necessary to study the possibilities and limitations of the gasification process. The plant is equipped with all necessary measurement devices for analysis of the process. The investigations must focus on the determination of ideal process parameters. Preliminary investigations of the gasification of olive residues showed, that the high alkali content is responsible for low ash softening temperatures. A low ash softening temperature can lead to agglomeration of bed material which inhibits the continuous operation of fluidized bed systems. In particular the utilization of olive bagasse in the past gave rise to systematic bed agglomeration beds at temperature above 800 °C. Therefore, the operating temperatures have to be lowered and additionally the used fuel type in a dual fluidized bed gasifier needs to ensure an ash melting behavior which prevents bed agglomeration.
This lead to following research questions:
• Which ash melting behavior of “exhausted olive pomace” (EOP) can be determined? • Are fuel pre-treatment steps before the gasification experiments necessary? • What are the typical gasification parameters for the fuel “exhausted olive pomace”? • What specific product gas volume flow and composition can be gathered? • How high is the tar content for the special design of the gasification reactor? • How high is the content of other impurities such as dust, char, H2S, NH3, etc. ?
For all test runs complete mass and energy balances are established via the software simulation tool IPSEpro. Thus, a verification of all measured values and a determination of directly immeasurable key-data such as heat losses, overall gas efficiency, product gas yields, calorific fuel (carbon) conversion and absolute/relative water conversion rates are possible. The average measurement results of a specific steady state operation are the basis of the simulation work with IPSEpro.
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2. RESULTS
2.1. FUEL PRE-TREATMENT AND FUEL ANALYSIS
2.1.1. CHARACTERIZATION OF EXHAUSTED OLIVE POMACE (EOP)
Before an experimental gas production from alternative feedstock, such as wasted olive pomace (WOP) or exhausted olive pomace (EOP), can be carried out, basic fuel parameters need to be analyzed to enable a decision about the precondition for an efficient gas production. Table 1 shows the analysis of different kind of biomass feedstock in comparison with exhausted olive pomace (EOP). The illustrated values have been determined by fuel tests in an appropriate laboratory. The results of the performed fuel characterization of exhausted olive pomace (EOP) show that the ash melting behavior of exhausted olive pomace is critical for the gasification process at high temperatures in a fluidized bed. The high alkali content is responsible for the low ash softening temperature. Low ash softening temperature can lead to agglomeration of bed material which inhibits a proper operation of the dual fluidized bed gasifier.
The illustrated results in Table 1 show that the chosen exhausted olive pomace (EOP) contains a critical ash melting behavior which very likely would lead to an agglomeration of the operated bed material in the gasification test plant. This would result in a breakdown of the fluidized bed system and stop a gasification test at an early stage. Experience with similar fuel types in the past showed, that the addition of limestone can be a strategy to improve the ash melting behavior of such fuel types. Therefore, this strategy has been chosen to analyze the preconditions for the scheduled gasification tests. As a part of preparation of the gasification experiment, the feedstock selected for the gasification tests at TU WIEN has been analyzed with respect to following requirements:
• The feedstock needs to be dried to a water content below 10 wt.-%, • the ash melting behavior needs to be improved by the addition of calcium carbonate (CaCO3), • and the size and shape of the fuel particles need ensure good pourability.
Therefore, following pre-actions have been taken before the gasification test runs:
• Full characterization of exhausted olive pomace (EOP) by a fuel test laboratory, • detailed analysis of the ash melting behavior of exhausted olive pomace (EOP), • analysis of the ash melting behavior of EOP mixed with calcium carbonate (CaCO3), • determination of necessary fuel treatment steps before the gasification experiments, • appointment of fuel supply for the gasification experiment, • and preparation of the experimental facility for the execution of the gasification experiment.
The results achieved are repeated within the present report to provide all gathered information for a precise assessment and interpretation of all results achieved.
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Table 1: Fuel characteristics of exhausted olive pomace in comparison with different kind of biomass including main chemical analysis of the used fuel 14020/1 for the gasification test run
1: VUT internal analysis data of fuel or ash; 2: calculated for moist fuel; 3: calculated dry base but with ash content for comparison; n.a.: not available
[1] Schmid, J.C., Wolfesberger, U., Koppatz, S., Pfeifer, C., Hofbauer, H., 2012, "Variation of Feedstock in a Dual Fluidized Bed Steam
Gasifier - Influence on Product Gas, Tar Content and Composition", Environmental Progress & Sustainable Energy, Vol. 31 (2), pp. 205-
2015, July 2012, Wiley, doi:10.1002/ep.11607
[2] Kitzler, H., Pfeifer, C., Hofbauer, H., 2012, "Gasification of different kinds of non woody biomass in a 100kW dual fluidized bed
gasifier", in: Proceedings of the 21st International Conference on Fluidized Bed Combustion (FBC), 3.-6. June 2012, Naples, Italy, pp. 760-
766, ISBN978-88-89677-83-4
[3] Miccio, F., Ruoppolo, G., Pinto, F., Gulyurtlu, I., Pfeifer, C., Hofbauer, H., Svoboda, K., Puncochar, M., Millan, M., Paterson, N., Maria
Sanchez, J., Maroño, M., Pelizza, M. L., Pesenti, A., Koch, M., Aichernig, C., Andersen, L., Morgan, T., 2012, "Near Zero Emission
Advanced Fluidised Bed Gasification (Flexgas) ", Final report, ISBN 978-92-79-22432-4
[4] Ollero, P., Serrera, A., Arjona, S., Alcantarilla, S., 2003, "The CO2 gasification kinetics of olive residue", Biomass & Bioenergy 24,
pp.151-161
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2.1.2. DETERMINATION OF NECESSARY FUEL TREATMENT
As described before, exhausted olive pomace (EOP) shows similar fuel parameters like regular soft wood chips but includes a different ash melting behavior. Table 2 presents a comparison of fuel parameters of exhausted olive pomace (EOP) with soft wood pellets. It can be seen, that there is a considerable difference of the ash melting behavior. Exhausted olive pomace (EOP) shows a significant lower softening temperature at a temperature of about 840°C. The low ash softening/melting temperature can be explained by a high share of alkali earth- and alkali metals in the ash. As displayed in Table 2, the share of potassium oxide (K2O) and sodium oxide (Na2O) have been measured significantly higher than in ash of regular softwood pellets. Although the presence of phosphor pentoxide (P2O5) can raise the ash melting point in general, in the present case it did not compensate the high amount of potassium and sodium. More detailed information about ash melting behavior can be found in literature.
Table 2: Fuel and ash analysis of soft wood pellets and exhausted olive pomace (EOP)
Investigations in the past indicated that the ash melting temperature can be raised by the addition of limestone (CaO, CaCO3). Therefore, further analysis have been carried out at the test laboratory of TU WIEN before the execution of the scheduled gasification experiments. As a part of this work, the ash melting behavior of exhausted olive pomace (EOP) mixed with limestone has been investigated. Exhausted olive pomace (EOP) samples have been grinded and mixed with different shares of calcium carbonate (CaCO3) and calcium oxide (CaO). Next, the produced samples have been reduced to its ash and compared with ash of pure exhausted olive pomace (EOP). Table 3 shows the results obtained.
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Table 3: Ash melting behaviour of exhausted olive pomace (EOP) in comparison with exhausted olive pomace (EOP) mixed with of limestone (% = wt.-%db)
Table 3 shows relevant temperatures describing the ash melting behavior of exhausted olive pomace (EOP) in comparison with exhausted olive pomace (EOP) mixed with 6 wt.-%db of calcium oxide (CaO), mixed with 4 wt.-%db of calcium carbonate (CaCO3) and mixed with 6 wt.-%db of calcium carbonate (CaCO3). The softening temperature indicates when the analyzed ash sample shows a first tendency of ash melting. It can be seen, that the softening temperature was lowered by the addition of calcium compounds. At the same time, all other temperatures describing the ash melting behavior showed significant higher values for ash samples of exhausted olive pomace (EOP) mixed with calcium compounds. This can be explained by following figures. Figure 5 and Figure 6 show single pictures of ash samples which had been heated up from 550°C up to 1500°C. Although softening of exhausted olive pomace (EOP) mixed with 6 wt.-%db of calcium carbonate (CaCO3) occurred at a lower temperature, a significant change of the profile could not be observed up to a temperature of 1500°C. Exhausted olive pomace (EOP) showed a significant change at temperatures above 850°C. Based on this result, the gasification experiment of work package 5 has been carried in the test plant with exhausted olive pomace (EOP) mixed with 6 wt.-%db of calcium carbonate (CaCO3) for a reduce risk of agglomeration during the operation of the fluidized bed system.
Figure 5: Ash sample of exhausted olive pomace (EOP) at 840°C (left) and exhausted olive pomace (EOP) mixed with 6 wt.-%db of calcium carbonate (CaCO3) at 750°C (right)
Figure 6: Ash sample of exhausted olive pomace (EOP) at 1445°C (left) and exhausted olive pomace (EOP) mixed with 6 wt.-%db of calcium carbonate (CaCO3) at 1450°C (right)
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2.1.3. PREPARATION OF PRE-TREATED EOP-PELLETS FOR GASIFICATION EXPERIMENTS
Pelletizing equipment (Figure 7) was necessary to prepare the pre-treated exhausted olive pomace (EOP) pellets for the scheduled gasification experiment in work package 5. Pre-treatment steps by the used of additional calcium carbonate (CaCO3) were necessary to improve the preconditions for the tests with the 100 kW laboratory test plant. The results of the preliminary fuel characterization showed that the addition of calcium carbonate (CaCO3) could be useful to improve the ash melting behavior. Therefore, the provided fuel from Mora Industrial S.A. was mixed with calcium carbonate (CaCO3). The following Figure 8 – 11 illustrate the pre-treatment of the fuel batch for the gasification experiments by the aid of a pelletizer shown in Figure 7. The carried out processing steps at the Laboratory of TU WIEN were:
1. grinding tests with the provided exhausted olive pomace batch with a hammer mill, 2. intermixing of exhausted olive pomace (EOP, Figure 8) with 6.6 wt.-% calcium
carbonate (CaCO3, 99.9 wt.-% purity, Figure 9) 3. pelletizing of the achieved mixture (Figure 10) by the aid of a small volume of water
with the pelletizer, 4. and finally drying of achieved pellets (Figure 11).
Figure 7: Pelletizer
Figure 8: Exhausted olive pomace (EOP)
before processing steps
Figure 9: Calcium carbonate (CaCO3)
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Figure 10: Exhausted olive pomace (EOP) mixed with
calcium carbonate (CaCO3)
Figure 11: Achieved pellets for the execution of
gasification test
The grinding tests with the exhausted olive pomace showed that this process step is important if the processed batch offers poor precondition for the pelletizing process. The first tests showed that the processed initial fuel batch offered very good characteristics for the pre-treatment and sufficient plasticity for the pelletizing process. Thus, the milling process step was not absolutely necessary. Consequently, the produced pellets showed defined physical properties with good pourability. As a result of the pre-treatment, exhausted olive pomace pellets containing additional calcium carbonate were made available for the scheduled experiment. Figure 11 shows these produced pellets which were used as fuel for the gasification test runs and Table 4 shows its chemical composition.
Table 4: Composition of EOP mixed with calcium carbonate used for gasification experiments
parameter unit value
Water content wt.-% 11.8
LHV (moist) kJ/kg 15240
Ash content wt.-%db 11*
Carbon (C) wt.-%db,af 52.4
Hydrogen (H) wt.-%db,af 6.2
Oxygen (O) wt.-%db,af 40.1
Nitrogen (N) wt.-%db,af 1.1
Sulphur (S) wt.-%db,af 0.11
Chlorine (Cl) wt.-%db,af 0.15
Typical ash deformation temp. (A) °C 750 - 840
Typical ash flow temp. (D) °C > 1440
*consists of 4.4 wt.-%db initial ash and 6.6 wt.-%db pre-mixed CaCO3
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2.2. OPERATIONAL PARAMETERS AND SETUP OF THE DFB GASIFIER SYSTEM
2.2.1. MAIN OPERATIONAL PARAMETERS OF THE FLUIDIZED BED REACTOR SYSTEM
This chapter presents the novel 100 kWth gasification test plant at the TU Wien. An overview of the plant equipment is shown in Figure 12. The arrows inside the scheme show flow paths of the solid streams and gas/fluid flows. All important plant parts of the main units are visible:
solid fuel supply/hopper system,
gasification reactor system, gas production,
gas cooling, cleaning and utilization,
process media supply systems,
measurement and control technology, control station,
safety technology.
Olivine sand and calcite mixtures are usually used as bed material for the fluidized bed reactors of the novel pilot plant. The main elemental compositions of different bed material types are shown in Table 5 & 6.
Table 5: Composition of olivine
parameter unit value
MgO wt.-% 48 - 50
SiO2 wt.-% 39 – 42
Fe2O3 wt.-% 8.0 – 10.5
Al2O3+Cr2O3+Mg3O4 wt.-% 0.7 – 0.9
CaO wt.-% < 0.4
NiO wt.-% < 0.1
CaCO3 wt.-% < 0.1
trace elements wt.-% < 0.1
hardness Mohs 6 – 7
particles density kg/m³ ≈ 2850
Table 6: Composition of limestone/calcite
parameter unit value
CaCO3 wt.% 95 – 97
MgCO3 wt.% 1.5 -4.0
SiO2 wt.% 0.4 – 0.6
Al2O3 wt.% 0.2 – 0.4
Fe2O3 wt.% 0.1 – 0.3
hardness Mohs 3
particles density kg/m³ ≈ 2650
particles density (after full calcination)
kg/m³ ≈ 1500
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Figure 12: Overview of the plant equipment used for gasification test runs (modified from Schmid J.C. 2014)
sam
ple
po
int A
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The basic principle of the novel dual fluidized bed gasification technology is shown in Figure 13. All important elements of the reactor system, as a part of the overall pilot plant equipment, are visible in the sketch of Figure 14. Loop seals, process media inputs, solids separators, cyclones and the feedstock/fuel input are clearly visible. The dashed line and the arrows inside the reactor system indicate the global solids circulation rate of the bed material. The fuel input is realized via screw feeder into the lower part of the gasification reactor (on-bed feeding onto the lower bubbling fluidized bed). There are specific requirements of the feeding system in order to ensure the transport of fuels with various calorific values and size distribution. In order to guarantee the highest safety demands, the two hoppers of the 100kWth gasification plant are locked gas tight and flushed with nitrogen. The range of several operating design parameters for the experimental test runs are listed in Table 7. An additionally drawing of the reactor system including measurement points is shown with Figure 15.
Figure 13: Schematic principle of the novel plant (Schmid J.C. 2014)
Figure 14: Novel dual fluidized bed reactor system (modified from Schmid J.C. 2014)
sample
point A
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Table 7: Typical operational design parameters of the used novel dual fluidized bed gasifier
parameter/name unit general
feedstock to gasification reactor
kW 40 – 110
typical feedstock properties - fuel as pellets
heat losses of the reactor system
kW 25 – 30
additional fuel input for temperature regulation & compensation heat losses
kW 30 – 57
pressure bar ambient conditions
bed material - olivine sand or calcite & mixtures
amount of bed material kg 75 – 100
parameter/name unit charge 1 charge 2 charge 3
bed material type - olivine olivine calcite
(limestone)
bed material size range μm 200 – 300 100 – 200 300 – 600
bed material particles density kg/m3 2850 2850 2650 (1500*)
bulk density of bed material kg/m3 1500 1500 1400 (800*)
typical bed material mixture wt.% 50 – 75 10 – 20 10 – 25
Parameter/name unit lower
gasification reactor
upper gasification
reactor
combustion reactor
range of temperature °C 700 – 850 800 – 950 830 – 980
regime of fluidization - bubbling bed turbulent zones fast bed
input gas for fluidization, gasification agent
- steam steam air
characteristic inner height of the reactor part
m 1.03 3.33 4.73
included separator system - freeboard zone
above bubbling bed
gravity separator followed by a
cyclone
gravity separator followed by a
cyclone
* after full calcination
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Figure 15: Sketch of the dual fluidized bed gasification
reactor system used for gasification test runs
(modified from Schmid J.C. 2014 & Pasteiner H. 2015)
Figure 16: Picture of the combustion reactor (before thermal insulation)
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Figure 17: Pictures of the novel dual fluidized bed reactor system without thermal insulation (left: upper reactor parts and hopper system, right: lower reactor parts)
Figure 18: Pictures of the novel dual fluidized bed reactor system with thermal insulation (left: upper reactor parts and hopper system, right: lower reactor parts)
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2.2.2. CONTINUOUS “ONLINE” MEASUREMENT EQUIPMENT
The product gas is filtered and washed with rapeseed methyl ester (RME) to remove the tar before measurement (see Figure 19). Main product gas components like H2, CO, CO2 and CH4 are analyzed by Rosemount NGA2000 measurement equipment, C2H4, C2H6, C3H8 and N2 values are measured with a gas chromatograph every 15 minutes (Perkin Elmer ARNEL - Clarus 500) (see Figure 20). A large number of temperature (thermocouples) and pressure sensors guarantee an effective process control and a smooth and continuous operation of the whole gasification facility. The measurement points are visible in Figure 21 and 25. All process media inputs are measured with high quality flow meters from the company Krohne. Every single value is logged with a data storage computer (see Figure 20).
Figure 19: Gas cleaning line for online product gas measurement
Figure 20: Online product gas measurement equipment (modified from Schmalzl 2014)
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Figure 21: Picture of the sampling point A for online analysis of the main gaseous product gas components
Figure 22: Picture of the product gas, flue gas and off
gas pumps with water condensation system
Figure 23: Picture of the online product gas, flue gas
and off gas measurement equipment
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2.2.3. DISCONTINUOUSLY MEASURED PRODUCT GAS CONTENTS
A standardized arrangement of sampling equipment is used to analyze the content of dust, water, char and tar in the product gas stream (Figure 24). The high molecular weight (heavy) tar compounds are quantified as the mass of tars left after vacuum evaporation of the solvent (toluene). This is referred as “gravimetric” tar. The medium molecular weight tar compounds such as naphthalene are detected by gas chromatography coupled with mass spectrometry (GC-MS). Since toluene is used as solvent, benzene, toluene, ethylbenzene, and xylene (BTEX) values are not detectable GC-MS tar components, but water can be easily detected. For more information of the measurement setup, see: CEN/TS 15439:2006 (Biomass gasification. Tar and particles in product gases. Sampling and analysis). The heat resistant ball valve (up to 450°C) and the arrangement of the sampling point in the product gas flow pipe to the secondary combustion chamber is shown in Figure 25.
Figure 24: Dust, char, water & tar sampling scheme
Figure 25: Picture of the product gas sampling point A for offline analysis
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Figure 26: Offline measurement procedure
A standardized arrangement of sampling discontinuously measurement is important to get information about additional contents like ammonia (NH3), sulphur (H2S) and chlorine (HCl) in the product gas. These contents originate from the elemental composition of the fuel itself. It is not possible to measure NH3, H2S of HCl at the same time due to different solvents of the measurement procedure. The sampling equipment is shown in Figure 27.
Figure 27: NH3, H2S, HCl sampling scheme
solvent for NH3, H2S or
HCl
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2.2.4. IPSEPRO-SIMULATION – MASS AND ENERGY BALANCE
The software package IPSEpro is used for evaluation and validation of the process data, which was gathered during the experiments. Furthermore, the mass and energy balance for the experimental runs is computed with this tool. IPSEpro is a software package originating from the power plant sector, which offers stationary process simulations based on flow sheet handling. The software uses an equation-oriented solver. To get data, which cannot be measured directly, a mass and energy balance is used. IPSEpro is minimizing the general error to a minimum. Following tables display also validated results of the simulation work. These validated results are highly valuable and representative for the scale-up of DFB gasification process. A detailed layout for the simulation work of the novel 100 kW gasification plant is shown in Figure 28.
Figure 28: Flow sheet for the simulation of the novel 100 kW gasification pilot plant (software: IPSEpro)
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2.2.5. GENERAL OVERVIEW OF THE GASIFICATION TEST RUN WITH EOP
An overview of the executed gasification test run with EOP, partially including the heat-up and shut down procedures, is displayed in Figure 29. An additional amount of calcite was added to the olivine bed material particles mixture of the reactor system at 14:00. The gasification was started by switching the fluidization from air to steam at around 14:20. From 14:30 to 15:50 different variations lead to the process parameter targets. The correct operational gasification conditions were reached at 16:00. The steady-state operation OP1 for the test run with nearly 100 kW fuel power was reached (OP1A). The fuel input was stopped shortly (16:35-16:45), for a measurement equipment maintenance procedure. Typical conditions for OP1 were reached quickly again (OP1B). The ash softening temperature of the used EOP pellets was measured before at around 750 to 840 °C. This temperatures were reached in the gasification and combustion reactor. Therefore, the possibility of bed material agglomeration was expected and has been observed after OP 2. During the steady-state phase an offline analysis for tar, water, dust, char, NH3 and H2S contents were taken from sample point A. In the last phase of the steady state operation (from 17:50) a gasification process with a higher steam to fuel ratio was examined (OP2). At 18:10 gasification temperature variation was carried out, but at the same time, first bed material agglomeration effects and increasing thermal fluctuations inside the combustion reactor (highest temperatures) were observed. Therefore, the steam gasification was stopped and the shut-down procedure of the test run was started at 18:15. Figure 29 shows an overview of temperatures, product gas composition and the sampling arrangement during the experiment. At 17:10 the temperature measurement TGR7 broke. For interpretation of the results from 17:10 TGR7 was replaced through TGR8 which is located close to the position of the broken temperature measurement.
Figure 29: Overview on the gasification test run, main product gas components (top), gasification reactor temperatures
(middle) and combustion reactor temperatures (down)
steady-state operation phases shut down procedure
switching to steam
heat up procedure
OP1 A OP1 B OP2
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2.2.6. RESULTS OF THE GASIFICATION WITH EOP: OPERATION POINT 1 (OP1)
During the steady-state phase OP1 a characteristically gasification temperature of 732-755°C was achieved for the lower gasification reactor (average value of OP1A & OP1B). In the counter-current turbulent fluidized upper gasification reactor temperatures up to 856°C were reached. Figure 30 – 36 show the results of the steady state phase in detail. Tables 8 – 11 display main relevant operational parameters. Figure 37 shows a comparison of the resulting tar, dust, and char values in comparison with typical values measured during the gasification of wood pellets. The comparable high dust values in the product gas which were measured during the gasification of EOP can be explained by the significant amount of limestone powder (CaCO3), which was fed to the gasification system.
16:05 16:10 16:15 16:20 16:25 16:30500
550
600
650
700
750
800
850
900
950
1000
1050
time [HH:MM]
tem
pe
ratu
re [
°C]
temperature GR 09-Dec-2015
TGR3
TGR6
TGR11
TGR22
tar NH3
H2S
TGR3
= 732 °C
TGR6
= 755 °C
TGR11
= 856 °C
TGR22
= 808 °C
Average temperatureof OP1A & OP1B
Figure 30: Overview on the temporal course of gasification temperatures of OP1A
Figure 35: Overview on the temporal course of the main product gas components of OP1B
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Table 8: Some parameters of OP1, gasification of EOP parameter/name unit gasification reactor combustion reactor
bed material types μm 100-300 (olivine), 250-400 (calcite)
bed material mixture wt.-% 78 (olivine), 22 (calcite)
overall initial bed material inventory kg 85
feedstock type - EOP -
feedstock/fuel analysis no. - PL-14020-A -
feedstock mass flow kg/h 19.8 -
feedstock/fuel power into GR kW 84 -
fuel to CR kW - 55
heat losses of reactor system (GR & CR) kW 26*
temperatures lower reactor part °C GR3: 732 GR6: 755 CR1: 784 CR4: 888
temperaturesupper reactor part °C GR 11: 856 GR22: 808 CR7: 859
gas temperature after cyclones °C 706 897
water content in the gas stream vol.-% 32 – 33 14 – 15
Table 9: Main gaseous product gas composition of OP1, gasification of EOP, sample point A
product gas composition, sample point A NGA2000 online
values
PE Arnel GC
values
IPSEpro
simulation
values parameter/name unit
H2 hydrogen vol.-% db 48.7 - 48.9
CO carbon monoxide vol.-% db 17.8 18.7 18.3
CO2 carbon dioxide vol.-% db 19.9 22.7 20.5
CH4 methane vol.-% db 6.6 7.9 7.0
C2H4 ethylene vol.-% db - 2.2 2.1
C2H6 ethane vol.-% db - 0.35 0.3
C3H8 propane vol.-% db - 0.01 0.01
additional gaseous product gas components typical values
PE Arnel GC
values parameter/name unit
N2 nitrogen vol.-% db 0.5 – 2.0 1.12*
sum of C4-.C5-hydrocarbons, NH3, H2S, HCl & other comp.
vol.-% db 1.0 – 4.0** -
* value because of purging/flushing feedstock hoppers and temp.&press.-measuring points with nitrogen
** value range strongly depends on the fuel composition (see fuel analysis & optional offline gas analysis)
Table 10: Additional product gas components of OP1, gasification of EOP, sample point A
product gas analytics, measured discontinuous, sample point A
parameter/name unit values
dust content g/Nm3
db 26.36
char content g/Nm3
db 3.35
tar content GC-MS g/Nm3
db 5.04
tar content gravimetric g/Nm3
db 2.32
water content, H2O vol.-% 33
Ammonia content, NH3 ppm 16260
Sulphur content, H2S ppm 575
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Table 11: Main gaseous flue gas composition of the combustion reactor of OP1
flue gas composition NGA2000 online
values
IPSEpro
simulation
values parameter/name unit
CO2 carbon dioxide vol.-% db 16.1 15.6
O2 oxygen vol.-% db 0.8 0.8
CO carbon monoxide vol.-% db 0.6 0.5
N2 nitrogen vol.-% db - 82.1
Ar argon vol.-% db - 1.0
Figure 36: Offline tar measurement OP1, impinger bottles after procedure
4.5 5.0
1.52.3
0.4
26.4
1.2
3.4
0
5
10
15
20
25
30
wood pellets S/F = 0.9 EOP S/F = 1.1
GCMStar
GCMStar
grav. tar
grav. tar
dust
dustcon
ten
t in
pro
du
ct g
as [
g/N
m3]
char
char
bed material: olivine & calcite mixture
TGR6 = 848 ° TGR6 = 755 °C Figure 37: GCMS & grav. tar, dust and char content in the product gas of OP1
sample
point A
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2.2.7. RESULTS OF THE GASIFICATION WITH EOP: OPERATION POINT 2 (OP2)
During the steady-state phase of OP2 the influence of a higher steam-to-fuel ratio compared to OP1 was investigated (S/FOP1 = 1.1, S/FOP2 = 1.6). Therefore, the steam input was increased. Gasification temperature remained nearly equal to OP1 in the lower part of the gasification reactor (743-754°C). In the counter-current turbulent fluidized upper gasification reactor temperatures up to 863°C were reached. Figure 38 to 40 show the results of the steady-state phase in detail. Tables 12 – 14 display additional operational parameters.
17:55 18:00 18:05 18:10500
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time [HH:MM]
tem
pe
ratu
re [
°C]
temperature GR 09-Dec-2015
TGR3
TGR6
TGR11
TGR22
TGR3
= 743 °C
TGR6
= 754 °C
TGR11
= 863 °C
TGR22
= 834 °C
Figure 38: Overview on the temporal course of gasification temperatures of OP2
17:55 18:00 18:05 18:10500
550
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950
1000
1050
time [HH:MM]
tem
pe
ratu
re [
°C]
temperature CR 09-Dec-2015
TCR1
TCR4
TCR7
TCR1
= 782 °C
TCR4
= 901 °C
TCR7
= 867 °C
Figure 39: Overview on the temporal course of combustion temperatures of OP2
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17:55 18:00 18:05 18:100
10
20
30
40
50
60
time [HH:MM]
ma
in p
rod
uct
ga
s co
mp
osi
tion
[vo
l.-%
db]
product gas GR 09-Dec-2015
H2
CO
CO2
CH4
tar NH3
H2S
H2
CO
CO2
CH4
= 54.1%
= 14.9%
= 19.6%
= 4.89%
+/- 1.7
+/- 2.4
+/- 0.82
+/- 0.53
Figure 40: Overview on the temporal course of the main product gas components of OP2
Table 12: Main results & parameters of OP2, gasification of EOP
parameter/name unit gasification reactor combustion reactor
bed material types μm 100-300 (olivine), 250-400 (calcite)
bed material mixture wt.-% 78 (olivine), 22 (calcite)
overall initial bed material inventory kg 85
feedstock type - EOP -
feedstock/fuel analysis no. - PL-14020-A -
feedstock mass flow kg/h 19.83 -
feedstock/fuel power into GR kW 84 -
fuel to CR kW - 55
heat losses of reactor system (GR & CR) kW 24*
temperatures lower reactor part °C GR3: 743 GR6: 754 CR1: 782 CR4: 901
Temperatures upper reactor part °C GR11: 863 GR22: 834 CR7: 867
gas temperature after cyclones °C 731 920
water content in the gas stream vol.-% 43 – 45 14 – 15
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Table 13: Main gaseous product gas composition of OP2, gasification of EOP, sample point A product gas composition, sample point A NGA2000
online values
PE Arnel GC values
IPSEpro simulation
values parameter/name unit
H2 hydrogen vol.-% db 54.1 - 54.6
CO carbon monoxide vol.-% db 14.9 14.3 14.5
CO2 carbon dioxide vol.-% db 19.6 20.2 19.8
CH4 methane vol.-% db 4.9 6.0 5.8
C2H4 ethylene vol.-% db - 1.7 1.7
C2H6 ethane vol.-% db - 0.33 0.3
C3H8 propane vol.-% db - 0.01 0.01
additional gaseous product gas components typical values
PE Arnel GC values parameter/name unit
N2 nitrogen vol.-% db 0.5 – 2.0 1.04*
sum of C4-.C5-hydrocarbons, NH3, H2S, HCl & other comp.
vol.-% db 1.0 – 4.0** -
* value because of purging/flushing feedstock hoppers and temp.&press.-measuring points with nitrogen ** value range strongly depends on the fuel composition (see fuel analysis & optional offline gas analysis)
Table 14: Main gaseous flue gas composition of the combustion reactor of OP2
flue gas composition NGA2000 online
values
IPSEpro
simulation
values parameter/name unit
CO2 carbon dioxide vol.-% db 17.2 17.5
O2 oxygen vol.-% db 0.4 0.4
CO carbon monoxide vol.-% db 0.6 0.6
N2 nitrogen vol.-% db - 80.6
Ar argon vol.-% db - 0.9
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2.2.8. COMPARISON OF PRODUCT GAS COMPOSITION OF OP1 AND OP2
The present chapter illustrates a brief comparison the achieved product gas composition during OP1 and OP2 with typical values occurring during the gasification of wood pellets. During the experiments with exhausted olive pomace (EOP), the gasification temperature was maintained on a comparably low level to keep an adequate operation temperature with respect to the identified ash deformation temperature. The gasification temperature GR 6, near the fuel input in the lower bubbling bed of the gasification reactor, was measured 755 °C during OP1 and OP2. Similar experiments in the past with wood pellets were operated at a temperature of around 850 °C. Figure 41 shows a comparison of experimental data from wood chips in comparison with results achieved with exhausted olive pomace.
Figure 41: Comparison of product gas composition, gasification of wood pellets and EOP (OP1 & OP2)
As can be seen in Figure 41, the experiments with exhausted olive pomace at lower temperatures led to high hydrogen contents and comparably low methane contents. The use of calcite in combination with low gasification temperatures can be on reason for this result. Furthermore, a transportation of carbon dioxide (CO2) from the gasification reactor to the combustion reactor has been observed. Increased steam-to-fuel ratio (S/FOP1 = 1.1, S/FOP2 = 1.6) additionally let to a high hydrogen (H2) content in the product gas. At the same time comparably low tar content has been observed during the experiments with exhausted olive pomace.
2.2.9. FURTHER PLANNED VARIATIONS OF PROCESS PARAMETERS
After the steam-to-fuel variation an additional temperature variation with a lowered gasification temperature was foreseen. Due to the low ash deformation temperature of the EOP bed material, agglomeration occurred around 18:10 after nearly 4 hours of operation. The gasification test run had to be stopped and the plant had to be shut down. This experimental result showed us, that agglomeration due to ash softening is main practical limitation for the utilization of EOP in fluidized bed systems.
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3. SUMMARY
3.1. CONCLUSION
The present reported illustrated extensive experimental data from exhausted olive pomace gasification test runs. Exhausted olive pomace (EOP) showed low ash softening temperature. The low ash softening/melting temperature can be explained by a high share of alkali earth- and alkali metals in the ash. This is a critical aspect for the operation of fluidized bed systems and typically led to agglomeration of bed material during the gasification tests. Thus, it was attempted to increase the ash softening/melting behavior by the addition of calcium carbonate (CaCO3). The usage of pre-treated exhausted olive pellets allowed the execution of gasification test with the novel test plant at TU Wien.
The gasification test campaign with different operation points lead to extensive experimental results. The achieved product gas showed a high heating value and contains nearly no nitrogen. The observed fuel conversion rate to product gas was significantly high. The hydrogen (H2) content of the product has been measured 50 vol.-% for all investigated operation points. The pressure profiles of the operation phases showed a very good accordance with previous cold flow and gasification test runs. The countercurrent upper gasification reactor operated highly active in terms of an increased gas-solid interaction. Gas-gas reactions and tar cracking was promoted. Thus, relatively low tar contents in the product gas were detected (2.3 g/Nm3 gravimetrical tar). It was possible to gasify exhausted olive pomace with steam in a fluidized bed after specific fuel pre-treatment, decreasing the gasification temperature and using a bed material with limestone/calcite for 4 hours. It can be clearly seen, that the new reactor concept is suitable in principle, because it is possible to set relatively low gasification temperatures in the lower part of the gasification reactor, at the same time guaranteeing higher temperatures in the upper part of the gasification reactor for effective tar cracking reactions. Furthermore, it can be clearly seen that low tar contents in the product gas have been achieved (especially in comparison with other alternative fuel types). But during the last phase of the experimental campaign agglomeration of the bed material, caused by ash melting, has been clearly observed. The experiment had to be stopped to protect the used equipment against potential damage. The gathered results with the “exhausted olive pomace” show a high potential for a future utilization of exhausted olive pomace. At the same time, a high risk in terms of agglomeration effects has been identified. Further experimental research and an optimization of process parameters have to be carried out with respect to agglomeration protection.
3.2. OUTLOOK AND SCALE-UP POTENTIAL
The presented experimental results are gathered from one of the first test runs in a novel test plant with an alternative fuel type and a defined bed material mixture of olivine and calcite. It has to be mentioned, that the ongoing optimizations of the new system will decrease operational limitations in future. The focus of interest should rest on a gasification test runs with lower process temperatures and other bed material types beside olivine. 100% calcite/limestone/dolomite (high availability, cheap, catalytically active, but soft) as bed material should be tested in the near future. Such experimental investigation at TU Wien can provide necessary data for the preparation of the basic design of a demonstration plant at a larger scale. The used dual fluidized bed is a robust system which offers the technological potential for a “scale-up” from 100 kWth to higher thermal power in general. But the results of gasifying “exhausted olive pomace” showed a high risk of bed material agglomeration. Thus, a scale-up cannot be advised at this stage of research and development. Beforehand, effective strategies have to be developed to avoid ash melting during the operation of the used fluidized bed.
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4. LITERATURE
Aigner, I., Koppatz, S., Pfeifer, C., Hofbauer, H., 2009, "Gasification of biomass and coal in a dual fluidized bed gasifier", Proceedings of the 9th European Gasification Conference, Düsseldorf, Germany
Hofbauer, H., 2011, "Dual Fluidized Bed Systems for Gasification and Looping Cycles", at: 3rd IEAGHG High Temperature Solids Looping Cycles Network Meeting, 30 - 31 Aug. 2011, Vienna, Austria
Hofbauer, H., Rauch, R., 2000, "Stoichiometric water consumption of steam gasification by the FICFB-gasification process", in: Progress in Thermochemical Biomass Conversion, Vol. 1, pp.199–208, ISBN 0-632-05533-2
Hofbauer, H., Stoiber, H., Veronik, G., 1995, "Gasification of organic material in a novel fluidized bed system", in: Proceedings of the 1
st SCEJ Symposium on Fluidization, Tokyo, Japan
Hofbauer, H., Veronik, G., Fleck, T., Rauch, R., 1997, "The FICFB gasification process", in: Bridgwater, A.V. & Boocock, D. (Eds.), Developments in thermochemical biomass conversion, vol. 2, Blackie Academic & Professional, Glasgow, U.K., pp.1016-1025.
Kaltschmitt, M., Hartmann, H., Hofbauer, H., 2009, "Energie aus Biomasse: Grundlagen, Technik und Verfahren", 2. Auflage, Springer-Verlag, Heidelberg, Germany, ISBN 978-3-540-85094-6
Kern, S., 2013, "Gasification and Co-gasification of Coal, Biomass and Plastics in a Dual Fluidized Bed System", PhD thesis, Vienna University of Technology, 2013.
Kitzler, H., 2012, "Gasification at the Vienna University of Technology - Possible feedstock and their properties for dual fluid steam gasification", at: Joined workshop of Vienna University of Technology and Chalmers University of Technology, 10-11 Dez. 2012, Götheborg, Sweden
Kitzler, H., 2013, "Zweibettwirbelschicht-Dampfvergasung von biogenen, ascheintensiven Brenn- und Reststoffen - Einfluss der Asche auf den Prozess", PhD thesis, Vienna University of Technology, 2013.
Kitzler, H., Pfeifer, C., Hofbauer, H., 2012, "Gasification of different kinds of non woody biomass in a 100kW dual fluidized bed gasifier", in: Proceedings of the 21st International Conference on Fluidized Bed Combustion (FBC), 3.-6. June 2012, Naples, Italy, pp. 760-766, ISBN978-88-89677-83-4
Kolbitsch, M., Schmid, J.C., Diem, R., Müller, S., Hofbauer, H., 2014, "Influence of Fuel Feeding Position on Sorption Enhanced Reforming in a Dual Fluid Gasifier" at: 11th International Conference on Circulating Fluidized Bed Technology (CFB11), 14-17 May 2014, Beijing, China
Kolbitsch, M., draft of dissertation, do be published in 2016
Koppatz, S., Schmid, J.C., Pfeifer, C., Hofbauer, H., 2012, "The effect of bed particle inventories with different particle sizes in a dual fluidized bed pilot plant for biomass steam gasification", Ind. Eng. Chem. Res., Vol. 51(31), June, 2012, pp10492-10502, DOI: 10.1021/ie202353b
Miccio, F., Ruoppolo, G., Pinto, F., Gulyurtlu, I., Pfeifer, C., Hofbauer, H., Svoboda, K., Puncochar, M., Millan, M., Paterson, N., Maria Sanchez, J., Maroño, M., Pelizza, M. L., Pesenti, A., Koch, M., Aichernig, C., Andersen, L., Morgan, T., 2012, "Near Zero Emission Advanced Fluidised Bed Gasification (Flexgas) ", Final report, ISBN 978-92-79-22432-4
Müller, S., 2013, "Hydrogen from Biomass for Industry - Industrial Application of Hydrogen Production Based on Dual Fluid Gasification", PhD thesis, Vienna University of Technology, ISBN: 978-3-9502754-5-2.
Ollero, P., Serrera, A., Arjona, S., Alcantarilla, S., 2003, "The CO2 gasification kinetics of olive residue", Biomass & Bioenergy 24, pp.151-161
PHENOLIVE FP7-SME-2013-1 – 605357 35
Schmid J.C. et al., 16.03.2016, Public report of scientific research: Gasification of exhausted olive pomace
Öhman, M., Pommer, L., Nordin, A., Bed Agglomeration Characteristics and Mechanisms during Gasification and Combustion of Biomass Fuels, Energy Fuels. 19 (2005) 1742-1748.
Pasteiner, H. A., 2015, "Cold Flow Investigations on a Novel Dual Fluidised Bed Steam Gasification Test Plant", Diplomarbeit, Institut für Verfahrenstechnik, Umwelttechnik und Technische Biowissenschaften, TU Wien, Juni 2015
Pasteiner, H., Schmid, J.C., Müller, S., Hofbauer, H., 2015, "Cold Flow Investigations on a Novel Dual Fluidized Bed Steam Gasification Test Plant", in: Proceedings 11. Minisymposium der Verfahrenstechnik, 14.-15. April 2015 an der BOKU, Wien, Österreich
Pfeifer, C., Koppatz, S., Hofbauer, H., 2011, "Steam gasification of various feedstocks at a dual fluidized bed gasifier: Impacts of operation conditions and bed materials", Biomass Conversion Biorefinery, Vol. 1, pp.39–53, doi:10.1007/s13399-011-0007-1
Pröll, T., Hofbauer, H., 2008, "Development and application of a simulation tool for biomass gasification based processes", International Journal of Chemical Reactor Engineering, Vol. 6
Roedder, E., Silicate Melt Systems. Printed in Great Britain by the Pitman Press, Batch. Printed from “Physics and Chemistry of the Earth, Vol 3”. Pergamon Press.
Saw, W., Pang, S., 2012, "Influence of mean gas residence time in the bubbling fluidised bed on the performance of a 100-kW dual fluidised bed steam gasifier", Biomass Conversion and Biorefinery, Vol. 2(3), pp.197–205, doi:10.1007/s13399-012-0036-4
Schmalzl, M., 2014, "Implementierung der MSR-Technik einer 100 kW DUAL FLUID Versuchsanlage zur Vergasung von Festbrennstoffen", Diplomarbeit, Institut für Verfahrenstechnik, Umwelttechnik und Technische Biowissenschaften, TU Wien, August 2014
Schmid, J.C., 2011, "Variation of Feedstock in a Dual Fluidized Bed Steam Gasifier", at: International Conference on Thermochemical Conversion Science (tcbiomass2011), 28 - 30 sept. 2011, Chicago, USA
Schmid, J.C., 2014, "Development of a novel dual fluidized bed gasification system for increased fuel flexibility", doctoral thesis, Institute of Chemical Engineering, Vienna University of Technology, August 2014, ISBN 978-3-9502754-6-9
Schmid, J.C., Müller, S., Hofbauer, H., 2014, "A Novel Dual Fluid Gasifier at Vienna University of Technology", in: Proceedings of the 1st International Conference on Renewable Energy Gas Technology (REGATEC), 22-23 May 2014, Malmö, Sweden
Wilk, V., 2013, "Extending the range of feedstock of the dual fluidized bed gasification process towards residues and waste", PhD thesis, Vienna University of Technology, 2013.
Wilk, V., Hofbauer, H., 2013, "Conversion of fuel nitrogen in a dual fluidized bed steam gasifier", Fuel, Vol. 106, pp. 793–801, 2013. doi: 10.1016/j.fuel.2012.12.056
Wilk, V., Kern, S., Kitzler, H., Koppatz, S., Schmid, J.C., Hofbauer, H., 2011, "Gasification of plastic residues in a dual fluidized bed gasifier- Characteristics and performance compared to biomass", in: Proceedings of the International Conference on Polygeneration Strategies (ICPS11), 30 August - 1 September 2011, Wien, Austria.
Wilk, V., Schmid, J.C., Hofbauer, H., 2013, "Influence of fuel feeding positions on gasification in dual fluidized bed gasifiers", Biomass and Bioenergy, Vol. 54C, pp. 46-58, 2013. doi: 10.1016/j.biombioe.2013.03.018.
