Fischer-Tropsch biomass gasification

Another option to extend the ligno-cellulosic feedstock base is the development of BTL through biomass gasification and subsequent Fischer-Tropsch synthesis. Although BTL is fully compatible with diesel fuel, ligno-cellulosic BTL has not yet been commercialised. 

In a first step, biomass is converted to synthesis gas by gasification. If Fischer-Tropsch (FT) synthesis is applied, a H2 CO ratio of about 2.1 1 is required for a maximum yield of liquid hydrocarbons. To adjust the H2 CO ratio, CO shift reactors are used to convert a part of the CO to H2 and C02 according to the following reaction ... 

The resulting synthesis gas can subsequently be converted into methanol (Reaction 3) or polymerized to a mixture of hydrocarbons via the Fischer-Tropsch synthesis (Reaction 4) [37, 38]. These conversions usually require a H2/CO molar ratio close to 2 (Reactions 3 and 4), which contrasts with the H2/CO ratio of 0.5 that is delivered upon biomass gasification (Reaction 2). It can therefore be suitable to adjust the H2/CO ratio through the water-gas shift reaction (Reaction 5) ... 

Depending on the reason for converting the produced gas from biomass gasification into synthesis gas, for applications requiring different H2/CO ratios, the reformed gas may be ducted to the water-gas shift (WGS, Reaction 4) and preferential oxidation (PROX, Reaction 5) unit to obtain the H2 purity required for fuel cells, or directly to applications requiring a H2/CO ratio close to 2, i.e., the production of dimethyl ether (DME), methanol, Fischer-Tropsch (F-T) Diesel (Reaction 6) (Fig. 7.6). 

Thermochemical biomass-to-liquid (BtL) conversion, involving thermal gasification of the biomass and subsequent synthesis of biofuels by the Fischer-Tropsch process. Various aspects of the use of catalysis in this process are discussed in the several chapters. 

The biomass is first processed by thermochemical methods (gasification, pyrolysis), for example, to form synthesis gas, which can be processed further to methanol or Fischer-Tropsch (FT-) hydrocarbons. To gasify solid biomass, both circu-... 

In addition, there is no useful direct access to methanol from biomass, and the synthesis gas route must be used (i.e. gasification of biomass with subsequent methanol synthesis). Compared to the Fischer-Tropsch synthesis, the efficiency of methanol synthesis is higher, which is certainly an advantage. However, this is overridden by... 

One way is the complete or partial destruction of natural biomass by pyrolysis or gasification to yield so-called bio-oil or syngas, respectively. While the downstream processes for syngas (Methanol, Fischer-Tropsch) are state of the art, smaller molecules generated by pyrolysis need a further pretreatment to be developed before they can be used in existing chemical process streams [16]. This is obviously a rather... 

Tijmensen MJA, Faaij APC, Hamelinck CN, van Hardeveld MRM. Exploration of the possibilities for production of Fischer Tropsch liquids and power via biomass gasification. Biomass Bioenergy. 2002 23(2) 129-52. 

Another approach to biomass-derived chemical production is the two-plat-form concept where the production of syngas (synthesis gas) from biomass gasification, or other technologies, is used to produced methanol or hydrocarbons through Fischer-Tropsch technology. ... 

Gasification, which involves heating a carbon containing substrate (coal, petroleum, biomass or municipal waste) to 500-1, 100 °C at 1-10 bar under controlled oxygen conditions, produces a mixture of CO and H2 (with smaller amounts of C02, CH4 and N2), which may be catalytically converted into hydrocarbons (via Fischer Tropsch), methanol or hydrogen [31,41], A major advantage of gasification... 

Since the 1920s the Fisher-Tropsch process (see http //www.fischer-tropsch.org, accessed 22 June 2013) [26] is the one most commercially exploited as a route to hydrocarbons. Through gasification of biomass (or other carbon sources such as coal or natural gas) a synthesis gas (syngas) composed mainly of carbon monoxide, carbon dioxide and hydrogen can be produced. 

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