Experimental study of an extruder‐feeder for biomass direct liquefaction

A new type of feeding system by an extruder‐feeder was utilized to pump high concentrations of slurries into an advanced biomass liquefaction reactor operating at pressures of up to 25 MPa and temperatures of up to 400°C. The operability of such an extruder‐feeder and the design criteria for this type of unit operation are described, and operational data are reported. Three types of extruder‐feeders were used, and many different types of feedstocks were tested. The extruder‐feeder proved to be effective in the biomass direct liquefaction process and could prove applicable in many other processes where high concentrations of solids are to be pumped, thus reducing drastically the size of the plant and the need for recycle of large amounts of liquid carriers for the solids. Typical experimental data and results of the flow rates and pressure generation for the various extruder‐feeders and their operational conditions for several feedstocks are reported. The theoretical models developed for plasticating extruders were found to be acceptable also for the extruder‐feeder of biomass feedstock, applying appropriate drag and pressure flow coefficients.