烟煤掺烧污泥HCl的排放和脱除实验研究

Experimental Study of HCl emissions and Removal During Combustion of Coal Mixed and Diluted with Sewage Sludge

污泥与煤混烧发电是一种较有发展前景的污泥处理方法,而混烧过程中产生的大量HCl气体会造成受热面腐蚀等危害。利用水平管式反应炉研究了升温速率、燃烧温度、污泥掺混比例以及反应气氛等因素对HCl释放的影响,考察了CaCO3添加量和添加温度对HCl脱除效果,并利用GAS-MET DX4000型红外气体分析仪实时测定HCl释放浓度。结果表明:随着污泥掺烧比例增加,HCl释放体积增加,而Cl→HCl转化率降低;温度升高会促进HCl释放,但600℃后Cl→HCl转化率变化不大;载气中氧气比例升高使得部分HCl转化为Cl2,导致样品中Cl→HCl转化率降低;高升温速率导致HCl释放峰值变大;Ca/(S+0.5Cl)摩尔比增大,则HCl脱除率增加,且Ca/(S+0.5Cl)摩尔比为2时,700℃是HCl脱除最佳温度。

Power generation by burning coal mixed and diluted with sewage sludge is a sludge treatment method with a relatively good prospect.However,a great amount of HCl gas produced during the combustion may result in such harms to the heating surfaces as corrosion and erosion.By making use of a horizontal tube type reactor,the authors studied the influence of such factors as temperature rise speed,combustion temperature,proportion of sludge mixed and diluted and reaction atmosphere etc.on the HCl release.Furthermore,the influence of the CaCO3 adding amount and temperature on the HCl removal efficiency was investigated and by using a GASMET DX4000 model infrared gas analyzer,the concentration of the HCl released was real-time measured.It has been found that with an increase of the proportion of the sludge mixed and diluted,the volume of the HCl released will increase while the conversion rate of Cl to HCl will decrease.To increase the temperature will promote the HCl release,however,after 600 ℃,the conversion rate of Cl to HCl will change little.The proportion of oxygen in the carrier gas will make a part of HCl converted into Cl2,resulting in a drop of the conversion rate of Cl to HCl in the sample.A high temperature rise speed will lead to a large peak value of HCl release.To increase the Ca/(S+0.5Cl) molar ratio will increase the HCl removal rate.When the Ca/(S+0.5Cl) molar ratio is 2,700 ℃ will be regarded as the optimum temperature for HCl removal.