Potential routes for thermochemical biorefineries

Abstract

This critical review focuses on potential routes for the multi-production of chemicals and fuels in the framework of thermochemical biorefineries. The up-to-date research and development in this field has been limited to BTL/G (biomass-to-liquids/gases) studies, where biomass-derived synthesis gas (syngas) is converted into a single product with/without the co-production of electricity and heat. Simultaneously, the interest on biorefineries is growing but mostly refers to the biochemical processing of biomass. However, thermochemical biorefineries (multi-product plants using thermo-chemical processing of biomass) are still the subject of few studies. This scarcity of studies could be attributed to the limitations of current designs of BTL/G for multi-production and the limited number of considered routes for syngas conversion. The use of a platform chemical (an intermediate) brings new opportunities to the design of process concepts, since unlike BTL/G processes they are not restricted to the conversion of syngas in a single-reaction system.Most of the routes presented here are based on old-fashioned and new routes for the processing of coaland natural-gas-derived syngas, but they have been re-thought for the use of biomass and the multiproduction plants (thermochemical biorefinery). The considered platform chemicals are methanol, DME, and ethanol, which are the common products from syngas in BTL/G studies. Important keys are given for the integration of reviewed routes into the design of thermochemical biorefineries, in particular for the selection of the mix of co-products, as well as for the sustainability (co-feeding, CO2 capture, and negative emissions).

Maximizing biofuel production in a thermochemical biorefinery by adding electrolytic hydrogen and by integrating torrefaction with entrained flow gasification

“…A water/steam electrolysis plant is such a consumer [7]. The hydrogen generated by the electrolyser could be converted back to electricity when the demand for electricity is high, but it could be more economically attractive as well as more environmentally attractive to have the opportunity to use the hydrogen for fuel production 2 . If the hydrogen is used for fuel production, a link has been created between the power grid and the transportation sector.…”

“…The conventional way of doing this adjustment is by changing the H 2/CO-ratio in the syngas by using the water gas shift (WGS) reaction (eq. 1) followed by removal of the produced CO2 [2]. This CO2 will typically be vented to the atmosphere, but if it was compressed and stored underground (CCS), the complete biorefinery would have the effect of reducing the CO2 content in the atmosphere and would thereby be a climate-mitigating technology.…”

Polygeneration of fuels and chemicals

“…The reader is referred to [49,50] for recent reviews of biorefineries, which include thermochemical biorefineries and hence, polygeneration.…”

Biomass gasification-based syngas production for a conventional oxo synthesis plant—greenhouse gas emission balances and economic evaluation

“…The production of DME (that e.g., could be produced via methanol dehydration) has also been studied for the aforementioned applications. The objectives of the studies include benchmarking technologies (Ciferno and Marano, 2002); reviewing potential routes (Haro et al, 2013a); conducting techno-economic assessments (Hamelinck and Faaij, 2002;Hannula and Arpiainen, 2014;Haro et al, 2013b); or combining techno-economic and carbon accounting assessments (Gilbert et al, 2014).…”