A moving-bed gasifier with internal recycle of pyrolysis gas

A co-current moving bed gasifier with internal recycle and separate combustion of pyrolysis gas has been developed with the aim of producing a design suitable for scaling-up downdraft gasifiers while maintaining a low tar content in the producer gas. Using wood chips with a moisture content of 7-9 wt% (db) as a fuel at a rate of 20 kg h(-1), this system produced a gas with a heating value of 4500 kJ m(s)(-3) and a very low tar content of <0.1 g m(s)(-3). Copyright (C) 1996 Elsevier Science Ltd