Fischer−Tropsch Synfuels from Biomass: Maximizing Carbon Efficiency and Hydrocarbon Yield

Abstract

According to various published process studies, efficiencies of biomass-to-liquid conversion may be expected in the range of 30−50% for chemical energy and 25−45% for carbon recovered in hydrocarbon products. Strategies for improving carbon conversion efficiency include minimizing O2 consumption in gasification and increasing synthesis selectivities and CO2 conversion during synthesis with hydrogen added from external sources. CO2 conversion during Fischer−Tropsch (FT) synthesis is possible with a CO/CO2 shift-active catalyst, if sufficient H2 is available. A combined experimental and modeling study has shown that equilibrium and kinetic limitations involved can be decreased by means of a membrane, which allows for in situ removal of H2O from the catalyst bed. The results help to quantify the effects of H2O permeability, permselectivities, and reaction conditions and help to indicate directions for further membrane development. This paper collects yield and efficiency estimates for FT synfuel production from biomass feedstocks. Limiting factors for the heating value output are discussed, and a conceptual/experimental study is presented that addresses in situ H2O removal by a hydrophilic membrane, aiming at maximizing carbon efficiency.

Carbon Management: Regional Solutions Based on Carbon Dioxide Utilization and Process Integration

“…For the conversion of the biomass a range of catalysts are available [23]. One of the options is the production of syngas, a mixture of CO (carbon monoxide) and hydrogen (H2), which is the main feedstock for the Fischer-Tropsch (FT) reactor in the GTL plants [24,25]. Another option is the production of biodiesel [19,26].…”

Optimal Operation of a Membrane Reactor Network

“…These measures did not yield any considerable improvements. Table 2 shows the configuration and the performance at the starting point (0), an intermediate step (1), and the final optimization results (2). Table 1 contains a comprehensive list of operational and geometrical parameters of the CPBMR that may be modified within given bounds.…”

“…However, this process demands enormous amounts of energy as noted by Unruh et al 1 and has an efficiency between 25 and 50% depending on reactant compositions and operating conditions. However, this process demands enormous amounts of energy as noted by Unruh et al 1 and has an efficiency between 25 and 50% depending on reactant compositions and operating conditions.…”

Pressure swing adsorption for CO2 capture in Fischer-Tropsch fuels production from biomass

“…The syngas has to be cleaned from impurities, such as tars, H 2 S and water, (purification) and adjusted to synthesis requirements (through a CO shift step) (Unruh et al 2010).…”

“…All kinds of biomass feedstock, including waste material (Batdorf 2010), can be used for liquid hydrocarbon conversion by FT, thus avoiding the competition with food production and improving waste management (Demirbas 2009;Unruh et al 2010). …”