FT Waxes –
the Next Generation of Candle Fuel Helmut Gutberlet
2
Overview
• Introduction
• Fischer Tropsch Process
• Structure and Properties of FT Wax
• FT Wax in Candle Application
• FT Wax Burning Characteristic
• Sustainability and Outlook
3
We all want to have beautiful candles of all types.
Will we be able to make them all in future?
4
Introduction
Worldwide Wax Demand
0
500
1000
1500
2000
2500
3000
3500
4000
4500
5000
2006 2011 2016 2020
Wax D
em
an
d i
n 1
000 t
on
s
Wax supply Wax shortageEstimated numbers
1 million tons 2.2 billion pounds
5
Introduction
Classification of Waxes
Polar
synthetic
waxes
6
Overview
• Introduction
• Fischer Tropsch Process
• Structure and Properties of FT Wax
• FT Wax in Candle Application
• FT Wax Burning Characteristic
• Sustainability and Outlook
7
Introduction
History of FT Process
Dr. Hans Tropsch
1889 - 1935
Prof. Dr. Franz Fischer
1877 - 1947
Inventors of the
Fischer-Tropsch (FT)
process in 1925
Kaiser-Wilhelm
Institute for Coal
Research, Mülheim,
Germany
8
Fischer-Tropsch Process
Some Hydrocarbon Molecules C24H50 n-alkane, linear
C7H16 iso-alkane, branched
C12H24 cyclo-alkane
Remark: FT waxes do not contain cyclo-alkanes
9
Fischer-Tropsch Process
Desulphurization
Reformer
Distillation Hydrogenation
15 to 50 bar, 200 to 350 °C
H2O + CH4 → CO + 3 H2
(2n + 1) H2 + n CO → CnH(2n+2) + n H2O
Waxes:
Low-melt, 30 °C, 86 °F
.
.
.
High-melt
115 °C, 239 °F
FT Synthesis
CH4
Supply forms
- liquid
- solid
10
Fischer-Tropsch Process
Feedstock Options
FT processes can be differentiated according to their feedstock
for synthesis gas production:
• Natural Gas – GTL, Gas to Liquid
• Coal – CTL, Coal to Liquid
• Biomass – BTL, Biomass to Liquid
11
Fischer-Tropsch Process
Other Products
The FT process does not only make wax, it can produce a
variety of products:
• Diesel
• Naphtha
• Jet fuel
• Base oils
• Liquid paraffin
• etc.
12
Fischer-Tropsch Process
Production Locations
Bintulu
Sasolburg
existing production
Qatar
13
Overview
• Introduction
• Fischer Tropsch Process
• Structure and Properties of FT Wax
• FT Wax in Candle Application
• FT Wax Burning Characteristic
• Sustainability and Outlook
14
FT Waxes – Structure and Properties
Crystals
orthorhombic crystals
cold and hard
hexagonal crystals
warm and soft
(melting point < 75 °C,167 °F)
congealing point
hot temperature cold
liquid solid solid solid
transition point
change of crystal type
no crystals
hot and liquid
15
FT Waxes – Structure and Properties
View with Optical Microscope
Paraffin wax - crystal habit.
It crystallizes in the form of
needles.
FT wax - crystal habit.
It crystallizes in
lamellar form.
16
FT Waxes – Structure and Properties
View with Electron Microscope
Paraffin wax crystals FT wax crystals
100 µm 30 µm
17
FT Waxes – Structure and Properties
Gas Chromatography (GC) – PW Fully 129/133 °F
0
1
2
3
4
5
6
7
8
9
10
Sh
are
in
%
Number of C-Atoms
n-alkane 75 %
iso-alkane 25 %
Paraffin wax
Fully 54/56 °C
18
FT Waxes – Structure and Properties
Gas Chromatography (GC), FT Medium-melt Wax
0
1
2
3
4
5
6
7
8
9
10
Sh
are
in
%
Number of C-Atoms
n-alkane 93 %
iso-alkane 7 %
FT medium-melt
19
FT Waxes – Structure and Properties
Gas Chromatography (GC), Micro Wax
0
1
2
3
4
5
6
7
8
9
10
Sh
are
in
%
Number of C-Atoms
n-alkane 17 %
iso-alkane 83 %Micro wax
20
FT Waxes – Structure and Properties
Congealing Points
FT waxes cover a wide range of melting and
congealing points:
from 30 to 115 °C, 86 to 239 °F
Terminology
FT medium-melt waxes:
50 to 70 °C, 122 to 158 °F
FT high-melt waxes:
70 to 115 °C, 158 to 239 °F
21
FT Waxes – Structure and Properties
Differential Scanning Calorimetry (DSC), Paraffin Wax
-4
-3
-2
-1
0
1
2
3
4
10 20 30 40 50 60 70 80 90
Heat
Flo
w in
mW
/mg
Temperature in °C
Heating Cooling
Paraffin wax
Fully 54/56 °C,129/133 °F
22
FT Waxes – Structure and Properties
Differential Scanning Calorimetry (DSC), FT Wax
-4
-3
-2
-1
0
1
2
3
4
10 20 30 40 50 60 70 80 90
Heat
Flo
w in
mW
/mg
Temperature in °C
Heating Cooling
FT medium-melt
23
FT Waxes – Structure and Properties
Oil Content
The oily portion of FT wax is not identical to that of paraffin wax:
• The “oil” of FT wax contains mainly branched hydrocarbons
• The “oil” of paraffin wax contains mainly cyclic hydrocarbons
FT waxes (and paraffin waxes) can be subdivided into the
following categories:
Oil content
Fully refined wax ≤ 0.5 %
Semi refined wax > 0.5 – 3 %
Scalewax > 3 – 6 %
Slackwax > 6 %
High oil content paraffinic slackwax,
non hydrotreated.
24
FT Waxes – Structure and Properties
Hardness, Penetration
0
20
40
60
80
100
120
140
160
180
200
20 25 30 35 40 45
Pen
etr
ati
on
in
0.1
mm
Temperature in °C
FT medium-melt
Fully 56/58
Microwax
FT high-melt
68 °F 113 °F
25
FT Waxes – Structure and Properties
Viscosity
0
2
4
6
8
10
12
14
16
70 80 90 100 110 120
Kin
. V
isc
os
ity i
n m
m²/
s
Temperature in °C
FT medium-melt
Fully 56/58
Microwax
FT high-melt
158 °F 248 °F
26
FT Waxes – Structure and Properties
Comparison with Paraffin Wax and Micro Wax
FT Medium
Melt Wax
Paraffin
Wax
FT High
Melt Wax
Micro Wax
Number of C atoms 20 – 45 20 – 45 20 – 110 20 – 75
n-alkane content 85 – 90 % 60 – 90 % 85 – 90 % 15 – 30 %
iso-alkane content 10 – 15 % 10 – 40 % 10 – 15 % 70 – 85 %
Aromatics 0 ppm 0 ppm 0 ppm 0 ppm
Sulphur 0 ppm ≤ 20 ppm 0 ppm ≤ 20 ppm
Congealing point 50 – 70 °C 122 – 158 °F
40 – 70 °C 104 – 158 °F
70 – 115 °C 158 – 239 °F
55 – 90 °C 131 – 194 °F
Oil content 0 – 4 % 0 – 6 % 0 – 2 % 0 – 4 %
Penetration @ 25 °C, 77 °F 10 – 40 [0.1 mm]
12 – 100 [0.1 mm]
< 10 [0.1 mm]
10 – 40 [0.1 mm]
Viscosity @ 100 °C, 212 °F 3 – 4,5 mm²/s
3 – 8 mm²/s
7 – 12 mm²/s
11 – 25 mm²/s
All waxes are hydrotreated. Food contact and pharmaceutical
grades of all waxes possible.
27
Overview
• Introduction
• Fischer Tropsch Process
• Structure and Properties of FT Wax
• FT Wax in Candle Application
• FT Wax Burning Characteristic
• Sustainability and Outlook
28
FT Waxes – Candle Application
General
FT waxes for candle production. What does that mean for
a manufacturer?
1) Supply forms
2) Storage
3) Candle types
4) Machines and production methods
5) Wicks
6) Colours and optical appearance
7) Fragrances
8) Other additives
29
FT Waxes – Candle Application
Supply and Storage
1) Supply forms of FT wax
• Bulk liquid
• Slabs
• Pastilles
• Powder
2) Storage of FT wax
a) Liquid – standard tanks, stainless steel is not required,
carbon steel is sufficient. 20 °C (68 °F) above melting point
b) Solid – dry at room temperature, no direct sunlight
30
FT Waxes – Candle Application
Candle Types and Production Methods
3) Candle types
• Pillar candles
• Jar candles
• Household candles
• Votive candles
• Dinner candles
• Tealights
• etc.
All candles with Ø ≤ 10 cm 4’’
are possible (one wick).
4) Production methods
• Extrusion
• Moulding
• Filling
• Pressing
• Drawing
• Dipping
31
FT Waxes – Candle Application
Machine Selection
Existing machines can be used.
Modification is not necessary.
e. g. pillar stamp press
e. g. pillar moulding
32
FT Waxes – Candle Application
Wick Selection
5) Proper wick selection is
the key for a good burning
candle
• FT waxes do not need new
wick types. All types of wicks
for paraffin wax are suitable
• Thickness of the wick might
be slightly thinner, because of
lower FT wax viscosity
• Wicks for FT wax need no
special chemical treatment
Standard wick for paraffin
wax is suitable
33
FT Waxes – Candle Application
Colours and Optical Appearance
6) FT wax candles can be coloured with
standard candle colours (liquid and
solid)
• Dyes for through-colouring
• Pigments for overdipping with standard
overdipping waxes
• Lacquers for surface finishing
Optical appearance
• Transparency varies form translucent to
opaque (similar to paraffin waxes)
• Mottling effect is possible
• High gloss surface
34
FT Waxes – Candle Application
No Dye
Fat
Paraffin Wax
FT Wax
Stearin
No dye
opaque
translucent
translucent
opaque
35
FT Waxes – Candle Application
Red Dye
Fat
Paraffin Wax
FT Wax
Stearin
Each sample coloured with the same dye and dye concentration
36
FT Waxes – Candle Application
Fragrance Selection
7) Fragrances for scented candles
• Fragrances that work well with
paraffin waxes can also be used with
FT waxes
• FT high-melt waxes can be used as
additive to improve oil binding
capability
• Fragrance intensity of “cold” and
“hot” FT wax candles are comparable
with paraffin wax candles
37
FT Waxes – Candle Application
Other Additives
8) FT waxes are completely miscible with other materials
such as:
• paraffin waxes
• fats, e. g. soy fat, palm fat, tallow etc.
• fatty acids, e. g. stearin (vegetable and animal based)
• beeswax
• polymer waxes, e. g. PE-wax
• stabilizers Jet stream mixing
38
Overview
• Introduction
• Fischer Tropsch Process
• Structure and Properties of FT Wax
• FT Wax in Candle Application
• FT Wax Burning Characteristic
• Sustainability and Outlook
39
FT Waxes – Burning Characteristics
Melting of Wax
Infrared pictures of burning FT wax and paraffin wax candles
FT wax Paraffin wax Paraffin wax
Pillar candle, Ø = 100 mm
Sequence: 8 hours
Paraffin wax FT wax
Container candle, Ø = 60 mm
Sequence: 5 hours
FT waxes and paraffin waxes show similar melting behaviour
40
FT Waxes – Burning Characteristics
Emission Comparison of Candle Fuels
2007
emission study
2013
new emission study
41
FT Waxes – Burning Characteristics
Emission Comparison of Candle Fuels
Ø = 60 mm h
= 2
4 m
m
Maxi light candle
What was new in the 2013 study?
• Commissioned by Sasol Wax only
• FT wax tested
• Palm fat tested
• Paraffin waxes with different
sulphur concentrations were tested
Sulphur is a good indicator of
paraffin wax purity. It should be < 20
ppm
42
FT Waxes – Burning Characteristics
Emission Comparison, Study 2013
0
10
20
30
40
50
60
70
80
90
Palm fat Paraffin2 ppm S
Paraffin10 ppm S
Paraffin40 ppm S
Paraffin240 ppm S
FT waxsulphur free
Stearin
Ran
kin
g v
alu
e
Low ranking value is better,
it means less emissions.
Only the sample paraffin wax (240 ppm S) exceeds some air quality standards
Compounds tested:
PCDD/PCDF
PAH
Aldehydes
SO2
Particulate matter
43
FT Waxes – Burning Characteristics
Energy Content of Candle Fuels
FT wax and paraffin wax are pure hydrocarbons. The combustion
reaches highest emissions in form of heat and light.
10.95 10.95
13.06 13.06
0
2
4
6
8
10
12
14
Fat Stearin Paraffin wax FT wax
Energ
y c
onte
nt in
kW
h/k
g
44
FT Waxes – Burning Characteristics
Emission of Light, Brightness of Candle Flames
0
0,05
0,10
0,15
0,20
0 2 4 6 8 10 12 14 Fuel consumption g/h
Qu
otie
nt (e
ffe
ctivity)
[cd
*h/g
]
Beeswax Stearin Fat FT wax / Paraffin wax Trend line Trend line Trend line Trend line
Beeswax
Stearin Fat
FT wax / Paraffin wax
FT waxes have a highly effective light emission over a wide
range of fuel consumption rates
45
Overview
• Introduction
• Fischer Tropsch Process
• Structure and Properties of FT Wax
• FT Wax in Candle Application
• FT Wax Burning Characteristic
• Sustainability and Outlook
46
FT Waxes – Sustainability
Sustainability is a complex issue.
Merely looking at the topic of renewability
would be too simple
• Is a resource used up or not? All factors that speed up or slow
down this consumption need to be assessed
• Product quality is important when looking at sustainability
• Storage stability of FT waxes and long shelf life of FT wax
candles reduce waste in production and use
• FT waxes have particularly low emissions. FT waxes are
completely free of sulphur
• FT waxes are not in competition with food production
47
FT Waxes – Outlook
• FT waxes with properties good for candle making will be a
more significant part of the wax supply in future
• A world scale FT plant will be required every 7 to 10 years, at
the current rate of decline of paraffin wax supply
• Such a plant will introduce fully synthetic products with
constant properties as it is possible to make tailor-made cuts
at different melt-points from 50 to 100 °C (122 to 212 °F)
• FT waxes fulfil the growing tendency for improved purity in
consumer products
48
FT Waxes – Summary
FT waxes
• are synthetically produced pure hydrocarbons
• have properties very similar to paraffin waxes
• are suitable for making all candle types
• are suitable for all candle production methods
• can be blended with all candle fuels, colours and fragrances
• have good burning properties and lowest emissions
From a practical point of view FT waxes and paraffin
waxes are interchangeable for candle production
49
FT waxes will help to make beautiful candles
of all types also in future
50
Acknowledgements
Dr. Thorsten Butz
Dr. Hendrik Eberhard
Kerstin Knauer
Gary Kok
Uwe Kurras
Kai Lüdeke
Dr. Maik Malessa
Dr. Gernot Meyer
Dr. Mark Veit
Dr. Glenda Webber
51
Thank you for your Attention