Coburning in institutional incinerators

Our program, initiated in 1980, originally sought to replace imported oil by coburning coal and natural gas in oil designed boilers. Success came in 1986 with the co-combustion of coal water slurries (CWS) and natural gas (G) in a 20 MMBtu/hr watertube oil designed boiler. We achieved stable flames over broad load levels, good boiler efficiencies, low emissions, benign ash and--by increasing the G/CWS ratio--full power rating. Our biomass-waste co-combustion experiments will utilize a two chamber ram fed incinerator. Advanced analytical techniques will be used to measure available energy and stack emissions from various waste-biomass-fossil fuel combinations. Heating values, H/C ratios, percent moisture, emissions, prices and tipping fees are discussed. Locally grown annual dry biomass yields of napiergrass and leucaena, energetically equivalent to 30-50 barrels of oil per acre, are reported. Abundant local sources of waste biomass are identified. Together community waste and cultivated and waste biomass constitute a substantial source of renewable energy of use in forested and agricultural regions. Modular waste to energy systems are available in the 10-100 ton per day range. With aggressive recycling and hazardous waste reduction measures and good combustion management and emission controls, emissions should be maintained at low levels. The results frommore » our system, a small modular waste-biomass to energy system, should be applicable to many institutions and small communities. 41 refs., 8 figs., 4 tabs.« less