含油污泥辐射热解传热模拟及能量分析

HEAT TRANSFER SIMULATION AND ENERGY ANALYSIS OF RADIATIVE PYROLYSIS OF OILY SLUDGE

油泥辐射热解过程复杂,热解炉内温度场和传热特性不明等,通过Fluent软件,选用双欧拉模型、DO辐射模型及多组分模型研究了热解炉内的温度分布及不同因素下物料的升温特性。结果表明,炉内油泥的温度分布以L/D=10为分界点将其分为了升温和恒温2个阶段,且600℃为最佳热解终温。同时,较高的含水率会延长油泥热解时间,而降低螺旋转速可减少最终油泥的剩余量。另外,在辐射管上方加装遮热板可改善炉膛温度分布的均匀性。最后,对整个热解系统进行能量平衡分析发现,热解产物总回收能量为6592.25 kJ,能量回收率最高可达82%,其中热解气能量占该系统总输入能量的65.78%~90.11%,可极大减少系统所需的外部能量补给。

Aiming at the complexity of oily sludge radiation pyrolysis,the temperature field and heat transfer characteristics inside the pyrolysis furnace are unknown.The temperature distribution inside the pyrolysis furnace and the heating characteristics of the materials under different factors were investigated by Fluent software,using double Eulerian model,DO radiation model and multi-component model.The results indicate that the temperature distribution of the sludge in the furnace was divided into two stages of heating and constant temperature with the cut-off point of L/D=10,and 600℃was the optimal pyrolysis final temperature.Meanwhile,higher water content prolongs the sludge pyrolysis time,while lowering the screw speed reduces the amount of final sludge remaining.In addition,setting a heat shield above the radiation tube can significantly improve the uniformity of the entire furnace temperature distribution.Finally,the total recovered energy of the pyrolysis products was 6592.25 kJ through the energy balance analysis of the whole pyrolysis system,with a maximum energy recovery rate of 82%.Among them,the pyrolysis gas energy accounts for 65.78%~90.11%of the total energy input of the system,which can greatly reduce the external energy supply required by the system.