回转窑热解气化炉处理生活垃圾特性

Gasification and Pyrolysis Characteristics of Household Garbage in a Rotary Kiln Gasifier

基于目前固定床热解气化法在常温下进行存在燃气热值和气化效率较低、燃料适用范围小和预处理复杂等问题,采用控制变量法设计探究了不同预热空气温度和过量空气系数对小型回转窑式热解气化炉处理村镇生活垃圾的影响.结果表明:预热空气温度升高有利于垃圾热解气化产气,但有一定的局限性,当温度超过600℃时垃圾的气化产气明显下降;当过量空气系数为0.4时,垃圾的热解气化效率达到最大值,并且焦油产量最小.垃圾原样在过量空气系数为0.4、空气预热温度为500℃下对底渣、飞灰进行重金属含量的分析测试结果显示,飞灰中的铅含量远高于GB 18598—2001《危险废物填埋污染控制标准》相关标准限值,需要经过处理才能排放,二英采样分析结果显示其含量均低于GB 18485—2014《生活垃圾焚烧污染控制标准》限值.研究显示,该回转窑式热解气化工艺处理生活垃圾的最佳过量空气系数为0.4,最佳空气预热温度为500℃,在此最佳工况条件下焦油产量小,飞灰及焦渣中重金属含量小,ρ(二英)低于0.10 ng/m^3.

Fixed-bed gasification has low gas heat v alue, low gasification efficiency, small fuel scope and complex pretreatment at room temperature. The influence of different preheated air temperature and excess air coefficient for municipal solid waste in a smal l , rotary kiln pyrolysis gasifier was studied with the control variable method. The result showed that the preheated air temperature rising is helpful for pyrolysis and gasification, but there are some limitations. When the temperature exceeded 600 ℃, the garbage gasification gas decreased obviously. The garbage reached the maximum value and gasification efficiency and minimized the tar yield when the excess air coefficient was 0. 4. The heavy metal contents in slag, fly ash and garbage were investigated at the conditions of excess air coefficient 0. 4 and air preheating temperature 500 ℃. The lead content in fly ash was much higher than the value in GB 18598-2001 Standard for Pollution Control on the Security Landfill Site for Hazardous Wastes, indicated a need for processing before being emitting. Dioxin sampling analysis results were below the value in GB 18485-2014 Standard for Pollution Control o n the Municipal Solid Waste Incineration. The results showed that the best excess air coefficient of the rotary kiln pyrolysis gasification process was 0. 4,and the optimum air preheating temperature was 500℃. Under the optimum conditions, the tar production, fly ash and coke slag heavy metal content was small, and dioxin levels were less than 0. 1 ng/m3.