Selected Results of experiments from the lab scale plant

The first experiments were used for investigating different FT-catalysts, gas cleaning methods and parameter variations. After variation of several parameters the conditions could be found to have stable operation of the FT-synthesis without any deactivation.

Typical temperature distribution over the FT reactor is shown in the following figure:

The FT-liquids produced during operation are collected in the liquid separators. Also in the FT reactor inside there is a change of the hydrocarbons. The waxes used for starting are replaced with the time by the long chain hydrocarbons produced by the FT reactions.

In the following figure the distribution of hydrocarbons in the reactor is given:

In the following figure the distribution of hydrocarbons collected in the offgas treatment is given:

To determine the chain growth probability the mathematical equation of the stepwise chain growth concept according to Anderson, Flory, Schulz was used.

Wn mass fraction of species with carbon number n
n carbon number
a chain growth probability

In the following figure the logarithms of (Wn /n) is displayed against the carbon number. For the plot the sum of the gas analyses, simulated distillation of the condensed product and the simulated distillation results from the slurry in the reactor are used. The abnormal behavior of the plot at the low carbon numbers can be a reason that the condensation of the product in Güssing is not complete or the gas analyses are not sufficient. For the compounds with a carbon number from C10 to C30 an a of typical 0.9 can be determined.

Analysis of the Diesel fraction

The fraction from the raw FT product with a boiling range from 180-320°C was used as Diesel and analysed by the Institute of Petroleum Processing in Poland. Here only the results of the Cobalt based catalyst are shown:

Properties	Unit	EN 590:2004		World Wide Fuel Charter, category 4		Method applied	Results of FT Diesel	Results of HPFT Diesel
		min	max	min	max
Cetane number	-	51,0	-	55	-	EN ISO 5165	75-85	65-80
Density at 15 o C	kg/m3	820	845	820	840	EN ISO 12185	770-790	770-780
Polycyclic aromatic hydrocarbons	%(m/m)	-	11	-	2,0	EN 12916	< 1	n.a.
Total aromatics content	%(m/m)	-	-	-	15	EN 12916	< 1	n.a.
Sulphur content	mg/kg	-	50	-	sulphur free (5)	EN ISO 20884	< 5	n.a.
Flash point	o C	>55	-	>55	-	EN 2719	87 to 91	80
Carbon residue	%(m/m)	-	0,30	-	0,20	EN ISO 10370	< 0,03	n.a.
Ash content	%(m/m)	-	0,01	-	0,01	EN ISO 6245	< 0,0015	n.a.
Water content	mg/kg	-	200	-	200	EN ISO 12937	200 to 300	n.a.
Total contamination	mg/kg	-	24	-	10	EN 12662	2 to 4	n.a.
Copper strip corrosion (3h at 50 °C)	rating	class 1		class 1		EN ISO 2160	class 1 a	class 1 a
Oxidation stability	g/m3	-	25	-	25	EN ISO 12205	< 5	n.a.
Lubricity, corrected wear scar diameter	m m	-	460	-	400	ISO 12156	340 to 360	n.a.
Viscosity at 40oC	mm2/s	2,00	4,50	2,00	4,00	EN ISO 3104	2.3 to 2.5	2.0 to 2.2
Oxidation stability	g/m3	-	25	-	25	EN ISO 12205	< 12	n.a.
Cold Filter Plugging Point, (CFPP)	o C	-	-20	-	-20	EN 116	-5 to 0	-50 to -60

Both direct FT Diesel, without any further treatment, but also diesel from hydroprocessing was produced and anaylsed. The direct FT diesel consists mainly of paraffins and has therefore a excellent Cetane number, but poor cold behaviour. the HPFT diesel from hydroprocessing has a high share of iso-paraffins and and excellent cold behaviour and still a very good Cetane number of about 70. Both diesel fractions were used for blending with fossil diesel and tested in diesel engines. As well known the FT diesel improves the properties of fossil diesel and emissions are reduced,as shown in the figure below.

Conclusion and Future work

As a result of current concerns about both crude oil prices and CO2 -accumulation in the atmosphere, biofuels play a major role in tomorrow's energy supply. Synthetic biofuels that can be produced from biomass via gasification and subsequent catalytic conversion of the synthesis gas compounds CO and H2 are one promising option to meet the ambitious goals set by the European legislation.

While typically only the synfuel is regarded as the desired product and co-products such as electricity and district heat are of negligible interest, in this concept a different approach is introduced. In polygeneration plants that purposively sacrifice some synfuel yield to the advantage of power production, a high degree of flexibility is obtained that allows to design the product mix to the specific needs of the market or of other production facilities. The latter may be especially valuable for the wood processing industry, as synergies with a complementary “energy centre” can be achieved. Furthermore, the use of low temperature heat for district heating which is possible in the small scale of up to 100 MW fuel power not only adds to the viability of the process, but significantly improves the overall efficiency and thus maximizes the amount of CO2 -savings.

Not only did the results of this work prove the energetic advantage of such trigeneration facilities, but equally promising break-even points were attained. Thus, the risk of the implementation of the technologies in a larger scale is reduced, as not only diversification applies, but also dependence on the yet developing synfuel technology is abated.

The next step will be a pilot plant in the scale of 1 barrel / day, where the project will start in beginning of April 2015.