Biomass Fischer-Tropsch synthesis

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. 

Fischer-Tropsch synthesis requires a stochiometric H2 CO ratio of 2.1 1. If coal or biomass are used as feedstock, the raw syngas contains much less hydrogen than needed. Hence, CO is reacted with water to form C02 and hydrogen in the shift reactor. As the C02 cannot be used in the Fischer-Tropsch synthesis, part of the carbon for fuel production is lost in this process. If external hydrogen is added to increase the H2 CO ratio, the carbon of the coal or biomass is more effectively used and the hydrocarbon product yield is improved. 

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) ... 

Considerable attention has been paid to the application of CNTs as the catalyst support for Fischer Tropsch synthesis (FTS), mainly driven by utilization of the confinement effect (Section 15.2.3). In general, this process is a potential alternative to synthesize fuel (alkanes) or basic chemicals like alkenes or alcohols from syngas, which can be derived from coal or biomass. The broad product spectrum, which can be controlled only to a limited extent by the catalyst, prohibited its industrial realization so far, however, it is considered an important building block for future energy and chemical resource management based on renewables. 

Fig. 3.8 Green diesel and other products from biomass via Fischer-Tropsch synthesis...

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... 

Within the Fischer-Tropsch research ECN Biomass concentrates on the definition of the gas cleaning with respect to the typical B R in urities, like NHj, HCl, HCN, H]S, COS, tars (heavy organic molecules), soot, and alkali metals, Traces (< ppm) of these compounds can already be a poison for the Fischer-Tropsch catalysts. For the implementation of B R and Fischer-Tropsch ECN its strategy is on the demonstration of integrated systems to reduce the time necessary to realise a first full-scale installation for conversion of biomass and residue, gas cleaning, and Fischer-Tropsch synthesis. To achieve this ECN focuses on two lines of development ... 

Back to Cl -chemistry by degrading biomass chemically or biochemically into small fragments (synthesis gas or methane) and building it up again into the desired structures in a controlled way. This technology is well known under the name Fischer-Tropsch synthesis and has been currently studied and improved by many academic and industrial research groups. 

Hu J, Yu F, Lu Y (2012) Application of Fischer-Tropsch synthesis in biomass to liquid conversion. Catalysts 2 303-326... 

Figure 2.37 Biomass to Fischer-Tropsch synthesis. Adapted from K. Salso, Andrite.

Jahangiri H, Bennett J, Mahjoubi P, Wilson K, Gu S A review of advanced catalyst development for Fischer-Tropsch synthesis of hydrocarbons from biomass derived syn-gas, Catal Sci Technol 4 8) 2210-2229, 2014. http //dx.doi.org/10.1039/c4cy00327f. 

Figure 6.11.9 XTL plant (X to liquid with X as natural gas, coal, biomass) with low or high temperature Fischer-Tropsch synthesis.

Gasification and Fischer-Tropsch synthesis Coal or biomass Diesel oil 40... 

Buragohain B, Mahanta P, Moholkar VS (2010) Thermodynamic optimization of biomass gasification for decentralized power generation and Fischer-Tropsch synthesis. Energy 35 2557-2579... 

Fischer-Tropsch synthesis of hydrocarbons from CO and H2 derived from biomass... 

Liquid synthetic fuels include shale oil and its various fractions coal liquids by cooking, by hydrogenation, and by Fischer-tropsch synthesis methyl fuel from coal or from overseas natural gas and liquid products from biomass, probably by gasification and Fischer-Tropsch synthesis. 

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