Open AccessPREFERENTIAL RECYCLING/REJECTION IN CFBC/FBC SYSTEMS USING TRIBOELECTROSTATIC SEPARATION
Author(s) -
Heng Ban,
J.M. Stencel
Publication year - 2004
Language(s) - English
Resource type - Reports
DOI - 10.2172/841462
Subject(s) - combustion , combustor , fluidized bed combustion , calcium oxide , waste management , calcium hydroxide , calcium looping , environmental science , calcium carbonate , chemistry , materials science , fluidized bed , process engineering , chemical engineering , engineering , calcination , biochemistry , organic chemistry , catalysis
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 the remainder recycled to the combustor. As a consequence, there is unburned carbon and partially used and 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