From Biomass to SNG

Luca Di Felice and Francesca Michelfi Chemical Process Intensification, Department of Chemical Engineering and Chemistry, Eindhoven University of Technology, Den Dolech 2, 5612AD, Eindhoven, The Netherlands 

Process Intensification for Sustainable Energy Conversion, First Edition. Edited by Fausto Gallucci and Martin van Sint Annaland. 

Currently, the attention is focused on the synthesis of both liquid biofuels - mainly FT-diesel products and methanol - and gaseous synthetic fuels such as dimethyl ether (DME) and substitute natural gas (SNG, which is addressed in this chapter) the main parameters (pressure, temperature, type of catalyst, H2/CO ratio) governing the different synthesis pathways of these fuels are reported in reference [4], 

On the other hand, between 2004 and 2006, total SNG production costs have been estimated to be in the range of 10-30 /GJ for capacities of 10-1000 MW, which increases by decreasing the plant size. Taking into consideration a natural gas price of 6 /GJ, the amount of subsidy required for the implementation of SNG production facilities (1.2-8.9 ct/kWh) has been estimated to be comparable with the range of financial support for producing electricity from biomass (6.0-9.7 ct/kWh), suggesting that this technology can be afforded [6, 7]. 

In this chapter, a brief description of the main bio-SNG facilities and projects in Europe is presented as well as the main process units (gasification, gas cleaning and methana-tion) integrated for bio-SNG production. Therefore, a case study for bio-SNG production is modeled by using the CHEMCAD 6.3.1.4168 software. Two process technologies, a fixed (adiabatic case) or fluidized (isothermal) bed methanation reactors are considered, while three different product gas compositions from real biomass gasification data are fed as input syngas for the modeled system. Einally, CH4 yield and chemical efficiency of the different cases are compared and discussed. 

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