CFD MODELLING APPLIED TO THE CO-COMBUSTION OF PAPER SLUDGE AND COAL IN A 130 T/H CFB BOILER

摘要

Three-dimensional mathematical model has been developed as a tool for co-combustion of paper sludge and coal in a 130 t/h Circulating Fluidized Bed (CFB) boiler. Mathematical methods had been used based on a commercial software FLUENT for combustion. The predicted results of CFB furnace show that the co-combustion of paper sludge/coal is initially intensively at the bottom of bed; the temperature reaches its maximum in the dense-phase zone, around 1400K. It indicates that paper sludge spout into furnace from the recycle inlet can increase the furnace maximum temperature (1396.3K), area-weighted average temperature (1109.6K) and the furnace gas outlet area-weighted average temperature(996.8K).The mathematical modeling also predicts that 15 mass% paper sludge co-combustion is the highest temperature at the flue gas outlet, it is 1000.8K. Moreover, it is proved that mathematical models can serve as a tool for detailed analysis of co-combustion of paper sludge and coal processes in a circulating fluidized bed furnace when in view of its convenience. The results gained from numerical simulation show that paper sludge enter into furnace from the recycle inlet excelled than mixing with coal and at the underside of phase interface.