Biomass to liquid processes

Frbhling, M., Kerdoncuff, P., and Rentz, O. (2009) Techno-economic and ecological assessment of a biomass-to-liquid process chain-a comparison for the feedstocks wood residues and straw. Proceedings of WREC 2009 Asia - World Renewable Energy Congress Asia, Bangkok, 19-22 May 2009. 

Olofsson, I. Nordin, A. Soderlind, U., Initial Review and Evaluation of Process Technologies and Systems Suitable for Cost-Efficient Medium-Scale Gasification for Biomass to Liquid Fuels, ETPC Report 05-02, University of Umea/Mid Sweden University, Umea, 2005, p. 90. 

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. 

An alternative to the utilization of food crops in biofuel production is lignocellu-lose, which can for instance be utilized in biomass-to-liquid (BTL) processes. That way, a direct competition between food and fuel production can be avoided. This feedstock is much more abundant than vegetable oils or sugar and starch crops. 

The FTS converts synthesis gas into mostly liquid hydrocarbons [12-15]. Depending on the origin of the synthesis gas, the overall process from carbon feedstock to liquid product is called gas-to-liquids (GTL), coal to liquids (CTL), or biomass to liquids (BTL). The product spectrum, however, is broader than liquid hydrocarbons alone and can include methane and alkanes, C H2 +2 (with n from 1 — 100), alkenes or olefins (C H2 n > 2), and to a lesser extent, oxygenated products such as alcohols. Hence the FTS offers the opportunity to convert gas, coal, or biomass-derived syngas into transportation fuels, such as gasoline, jet fuel, and diesel oil, and chemicals, such as olefins, naphtha, and waxes. The reactions need a catalyst, which in commercial applications is either based on cobalt or iron. 

Knowledge of the effects of various independent parameters such as biomass feedstock type and composition, reaction temperature and pressure, residence time, and catalysts on reaction rates, product selectivities, and product yields has led to development of advanced biomass pyrolysis processes. The accumulation of considerable experimental data on these parameters has resulted in advanced pyrolysis methods for the direct thermal conversion of biomass to liquid fuels and various chemicals in higher yields than those obtained by the traditional long-residence-time pyrolysis methods. Thermal conversion processes have also been developed for producing high yields of charcoals from biomass. 

An alternative way to utilize renewable biomass is the so-called biomass-to-liquids (BTL) process. Parallel with GTL and CTL, BTL is essentially a variant of the F-T process that uses biomass as a feedstock. Hydrophilic zeolite membrane can also play an important role in the downstream dehydration process. 

Biomass is predominantly eomposed of biopolymers, for example cellulose, hemieellulose, and lignin. From a molecular viewpoint, converting non-food biomass to liquid fuels is a process of transforming solid-phase macromolecules into liquid-phase small molecules. Simultaneously, it is necessary to reduce the oxygen content of the small molecules to improve the energy density. 

Furthermore, in recent years this reaction has become a crucial step in the biomass-to-liquid (BTL) process in which the biomass is first gasified to biosyngas and then is converted into hydrocarbons by the FT process. The essential target of BTL is to produce paraffins and olefins with different molecular weight and to limit the formation of methane and carbon dioxide (CO2). When syngas is produced from biomass or coal, it is characterized by a low H2/carbon monoxide (CO) ratio, approximately 1/1, lower than the stoichiometric amount required by FT synthesis. 

In addition to pyrolysis and gasification, there are processes in which high-viscosity liquids which are nonsoluble in water are obtained from solid biomass by liquefaction (i.e., the direct biomass to liquid (BTL) process).This conversion can be accomplished at... 

The pyrolysis plant will be built near Hengelo in The Netherlands and has a processing capacity of 120t/d biomass ( 25MWtij). Recently (February 8, 2014), it was announced by Empyro BV through a press release that construction of the first pyrolysis plant (biomass to liquid) has started at the AkzoNobel site in Flengelo (The Netherlands). By the end of this year, construction will have been completed. The production capacity will then be gradually increased to its maximum of >20 million liters of pyrolysis oil per year. This amount of renewable oil will replace 12 million cubic meters of natural gas, the equivalent annual consumption of 8000 Dutch households, which saves up to 20,000 tonnes of CO2 emissions per year. 

Gas to liquid process including manufacturing machinery, utilities and chemicals are included within the system boundary of the conversion system as shown in Figure 1. Furthermore, the system also includes the production of diesel from biomass including both biomass harvest and diesel production. However, the use of diesel in fuel combustion is outside of the system boundary. The functional unit in this study is defined as 1 kilogram of diesel produced from gas or biomass. 

BTL [Biomass To Liquids] A general name for processes that convert biomass to liquid fuels. Examples are BTG, Carbo-V, Coskata, MKS, and RTP. A version of the PRENFLO process, originally developed for gasifying coal, can be used as the first stage. 

NExBTL [NEste Biomass-to-Liquids] A process for converting triglycerides (animal or vegetable) into biodiesel without producing glycerol. Developed by Neste Oil and first operated at Porvoo, Finland. Awarded the 2006 Finnish Chemical Industry Innovation Award. Plants in Singapore and Rotterdam were built in 2010... 

---