Operating Experience with a Large Fluidized-Bed Gasifier of Woodwaste

Abstract

The town of Hearst in northern Ontario is the location of many forest product industries. One enterprising manufacturer of plywood and particleboard found that his daily production of waste almost exactly equaled in energy content his purchases of natural gas for his factory. He ordered an Omnifuel fluidized-bed gasifier, which has been in operation since April, 1981, and which is currently believed to be the largest commercial biomass gasifier in operation with a rating of 80 million BTU/hr.

The gasifier accepts any material including chips, shavings, sawdust and sanderdust. Large pieces are hogged to fist-sized lumps. No drier is used. Minimum chars or tars are produced. The system is designed for round-the-clock unattended operation, and the first few months saw a continuous improvement in reliability as debugging continued. The plant feeds a hot combustible gas to four boilers in various locations, with natural gas available as standby.