//Fill Your Tank With Straw at $3 a Gallon

Fill Your Tank With Straw at $3 a Gallon

Liquid Motor Fuel from Biosyncrude Gasification Process Could Cost Around $3/gallon

The Bioliq biosyncrude gasification process used in a large plant with a capacity greater than 1 Million tons per year could produce biosynfuel (biodiesel) for about US$3 a gallon, according to an analysis by researchers in Germany.

For comparison, a crude oil price of US$100 a barrel results in an approximate cost of  $2.72 a gallon without tax for conventional motor fuel.

Bioliq is a three-stage process, where raw material in the form of biomass, in the current tests straw is being used, but it could be any plant  matter above a certain energy value. The first stage creates pyrolysis oil, which is extracted by destructive distillation from dried biomass in a reactor at temperature of about 500°C with subsequent cooling. The pyrolysis oil is mixed with pyrolysis coke from the process to create a biocrude slurry for transport and subsequent gasification to syngas and subsequent catalytic conversion to chemicals and/or fuels.

A key technology in the process is the centralized oxygen-blown, slagging-entrained flow gasifier operating at high pressure above the downstream synthesis pressure to avoid expensive intermediate syngas compression, according to FZK. The reaction chamber is enclosed by a membrane wall, cooled with pressurized water and can accommodate feed with much ash. Because of the high gasification temperature (above ca. 1,200 °C), the raw syngas is practically tar-free and has a low CH4 content; thus simplifying downstream syngas cleaning.

The biosyncrude is well suited for energy-dense storage and transport, resulting in lower transportation costs and large biomass delivery areas.

Because of the complex technology to be applied, BTL plants for biosynfuel production can only be economic in large facilities, the researchers say. Furthermore, given the limitations on biomass conversion to biosynfuel, the FZK team sees an ongoing role for coal and natural gas derived synthetic fuels, likely combined with BTL in very large integrated XTL complexes.

The energy efficiency of biomass conversion to biosynfuel via syngas as intermediate is only about 40%. A substitution of the present 2008 global motor fuel consumption of 2 Billion tons a year would therefore require a biomass harvest of 4 Billion tons a year. This is four times the present global bioenergy consumption of 1 Billion tons a year and will probably be at the limit of a sustainable level. Therefore a complete substitution of fossil motor fuels by biosynfuel would be impossible.

A sustainable long-term supply with liquid hydrocarbon fuels seems possible only for special applications where liquid fuels are hard to replace, such as aviation fuel. This sustainable level probably is less than a quarter of the future transportation energy consumption.

Lurgi, a 100% subsidiary of the Air Liquide Group, is beginning work on the second stage of a pilot plant at Forschungszentrum Karlsruhe (FZK), Germany to demonstrate the viability of the Bioliq biomass-to-liquids process.

The European Union requires that the proportion of biogenic motor fuels should be increased to 5.75% by the year 2010 to continue cutting greenhouse gas emissions. In Germany, the Federal Government is aiming for an even higher quota of fuels generated from renewable resources by year 2020.