NREL have been developing their 36 kg/h vortex ablative pyrolyser since 1980. Designs for scale up have been produced and support has been provided to Interchem for the reactor in their 31 te/d demonstration plant (see below). A second R&D unit has now been constructed and a small fluid bed fast pyrolysis unit has also been commissioned. Zeolite upgrading of the pyrolysis vapours to aromatics has been accomplished at the fundamental level on the MBMS system, on a slip­stream of the vortex reactor and on the full reactor output. Novel multi-functional zeolite catalysts have been produced and tested. A circulating fluid bed zeolite cracker with regenerator is under construction. Only limited results have been published on any of this work including recent work by Czernik et al. (13) on vapour phase thermal treatment to lower the oxygen content of the liquid.

3.5.1J3____ Interchem

The 31 te/d demonstration plant was moved from Mountain View Missouri to Kansas City and the reaction system completely redesigned with the support and assistance of NREL (14). The construction of the new reactor was completed in late summer 1993 and work has now stopped on the project. Future plans are unclear.

3.5.1.4 BBC

A 10-25 kg/h unit was constructed to investigate the reactor parameters of surface temperature and gas/vapour product residence time and particle size. Although the unit was built to pyrolyse tyres, it is capable of using wood, MSW and other similar materials as a feedstock. Limited details of the continuous ablation reactor are available (15). Particles up to 6 mm have been used with liquid recovery in a two stage direct liquid quench of the product vapours with recycled liquids after char removal in a high temperature cyclone. Liquids are collected in a sump tank and are returned to quench the hot vapours via a water cooled heat exchanger. Liquid yields of 54% have been obtained from tyres at 470-540*C at 0.88 s residence time and 1.3 mm size particles (16). A 35-50 t/d plant has been built in Nova Scotia where it is operating successfully with combustion of the raw product gas and no liquids collection.