Sensible Heat Recovery of Hot Coke Oven Gas Using Direct Contact Heat Transfer and Gravity Separation

摘要

The temperature of crude coke oven gas,COG,at the coke oven outlet usually ranges from 600℃ to 900℃.This sensible heat of the COG,however,is universally wasted due to the high level of tars and soot that would build up on heat exchanger surfaces,and only the chemical energy of the COG is recovered.The wasted sensible heat becomes about 17％ of the total energy of the crude COG,while the recovered chemical energy is usually in a range of around 60％ and the rest is carried by the tars.In this study,a new approach using direct contact between the crude COG and showered molten tin as a heat medium and gravity separation between the molten tin and the tars is proposed for the sensible heat recovery of the crude COG.The size of a direct contact heat exchange tower for the tin shower is decided using numerical analysis with empirical formulae for heat transfer between gas and droplets.Sulfuration of the tin in the crude COG was experimentally investigated.The target recovery performance by direct contact heat transfer with heat exchange efficiency of 95％ saves 11％ of the 17％ wasted sensible heat.