Pyrolysis, flash entrained reactors

Thermochemical Liquefaction. Most of the research done since 1970 on the direct thermochemical Hquefaction of biomass has been concentrated on the use of various pyrolytic techniques for the production of Hquid fuels and fuel components (96,112,125,166,167). Some of the techniques investigated are entrained-flow pyrolysis, vacuum pyrolysis, rapid and flash pyrolysis, ultrafast pyrolysis in vortex reactors, fluid-bed pyrolysis, low temperature pyrolysis at long reaction times, and updraft fixed-bed pyrolysis. Other research has been done to develop low cost, upgrading methods to convert the complex mixtures formed on pyrolysis of biomass to high quaHty transportation fuels, and to study Hquefaction at high pressures via solvolysis, steam—water treatment, catalytic hydrotreatment, and noncatalytic and catalytic treatment in aqueous systems. 

Several studies have been published describing results from the flash pyrolysis of biomass. Most of these studies were carried out at higher temperatures and were intended to promote biomass gas production. However, the work of Roy and Chornet [4] reported high liquid yields from biomass pyrolysis under vacuum conditions. More recently, Roy et al. [5] have described a vacuum pyrolysis system for the production of liquids from biomass, based on a multiple hearth type of reactor. Knight et al. [6] have developed an upward flow entrained pyrolyzer for the production of liquids from the thermal pyrolysis of biomass. 

A related flash pyrolysis process, the Rockwell process, uses hydrogen as the carrier gas in entrained flow reactors which is claimed to improve the yield of products (Oberg and Falk, 1980). 

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