Preferential recycling/rejection in CFBC/FBC systems using triboelectrostatic separation

Ban, Heng ; Stencel, J.M.

Federal Energy Technology Center (U.S.)

关键词: Efficiency;    Combustion;    Recycling;    01 Coal, Lignite, And Peat;    Power Generation;   

DOI  :  10.2172/781808
RP-ID  :  DE--FG26-97FT97272--03
RP-ID  :  FG26-97FT97272
RP-ID  :  781808

美国|英语

来源: UNT Digital Library

【 摘 要 】

Circulating Fluidized Bed Combustion (CFBC) and Fluidized Bed Combustion (FBC) with recirculation are widely used technologies in the US for power generation. They have the advantage of fuel flexibility, and low NO{sub x} and SO{sub x} emissions. Typically, as partially combusted fuel is circulated in the system, only a split stream of this circulating stream is rejected, with remainder recycled to the combustor. As a consequence, there is unburned carbon and partially used, valuable, calcium hydroxide in the reject stream. If these useful materials in the reject stream can be recovered and sent back to the combustor, the efficiency of the system will be increased significantly and the equivalent emissions will be lower. This project studies an innovative concept to incorporate triboelectric separation into CFBC/FBC systems in order to preferentially split its recycle/reject streams based on material compositions of the particles. The objective is to answer whether useful constituents, like carbon, calcium carbonate and calcium hydroxide or oxide, can be selectively separated from combustion ash at elevated temperatures. Laboratory experimental studies are performed at temperatures from 25 C to 210 C, the data from which are presented in the form of recovery curves. These curves present quality-versus-quantity information useful for predicting the efficacy of triboelectric separation as applied to CFBC/FBC byproduct recycling and/or rejection.