Biomass hydrothermal liquefaction

Hydrothermal liquefaction is a process for the conversion of biomass into an organic product oil. It has been widely studied in the early 1980 s (see the recent extensive literature survey in [1]), Starting in 1983 Shell Research performed process development based on experiments in autoclaves and a continuous bench scale unit. This resulted in a conceptual design for the HTU process including cost estimate [2,3]. The work was discontinued in 1988. 

When the temperature is increased to 250—375°C, hydrothermal liquefaction reactions start to dominate. During liquefaction, the biomass is decomposed to smaller... 

The general steps anticipated in a modem hydrothermal liquefaction facUity are summarized in Fig. 17.6(a) for hgnoceUulosic biomass. The processing and pumping of feed slurries of low particle size may require pretreatment for certain feedstock. For woody biomass this typically includes size reduction and alkaline treatment to obtain a pumpable and stable slurry. 

Elliott, D.C., et al., 2015. Hydrothermal liquefaction of biomass developments from batch to continuous process. Bioresource Technology 178 (0), 147—156. 

Jones, S.B., et al, 2014. Process Design and Economics for the Conversion of Algal Biomass to Hydrocarbons Whole Algae Hydrothermal Liquefaction and Upgrading (p. Medium ED ... 

Zhu, Y., et al., 2014. Techno-economic analysis of hquid fuel production from woody biomass via hydrothermal liquefaction (HTL) and upgrading. Applied Energy 129 (0), 384-394. 

Hydrothermal liquefaction of biomass and hydrotreating of the biocrude product. 

The future for hydrothermal liquefaction and subsequent hydrotreating may be more straightforward. Although the biomass conversion process development lags years behind fast pyrolysis, the increasing interest in the R D community and the perception of a more simple hydroprocessing step is likely to move the technology forward more quickly. 

Liquefaction of wet biomass streams is done by hydrothermal processes at elevated pressures. The feed stocks for these high pressure liquefaction processes are slurries of biomass particles and water. Feeding these slurries into the high pressure equipment, at reasonable costs, is an important hurdle in the process development. For example, the reported operating conditions for high pressure liquefaction are in the range 280-360 °C and 90-250 bar [25, 26]. Under these conditions, biomass is converted, in a complex sequence of chemical reactions, into various compounds. Upon cooling, the reactor effluent consists of three... 

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