矿化垃圾衍生燃料热解过程HCl与H_2S析出规律

采用热重红外质谱联用法(TG-FTIR-MS)和水平管式热解炉/化学吸收法,对比研究了矿化垃圾(ARDF)和常规垃圾(NRDF)衍生燃料热解过程腐蚀性气体(HCl和H_2S)的析出特性,分析了热解温度及热解类型对析出行为的影响并对热解固相产物腐蚀性元素的赋存特点进行了考察。结果表明,慢速热解过程,两者腐蚀性气体的析出特征温度区间相似,均分为两段,HCl析出区间为200-400和420-500℃,H_2S析出区间为230-370和380-670℃,而ARDF表现为较低的HCl和H_2S析出率;快速热解过程,两者腐蚀性气体的析出受热解温度影响较大,且规律有所差别:随热解温度的升高,HCl析出率呈S型变化(先高后低再高),而H_2S析出率呈正相关,均在850℃达到峰值,其中,HCl析出率分别为48.8%(ARDF)和29.4%(NRDF),H_2S析出率分别为6.8%(ARDF)和44.6%(NRDF)。因腐蚀性气体差异性的析出规律,两类垃圾热解固相产物腐蚀性元素的赋存与热解温度相关,ARDF的Cl和S元素最高赋存率分别可达59.4%(450℃)和84.3%(750℃),而NRDF的Cl和S元素最高赋存率分别仅为36.7%(850℃)和15.2%(650℃)。说明在合适的热解条件下,相比NRDF,ARDF腐蚀性元素不易释放,倾向于固相赋存,此为不同垃圾衍生燃料的热利用提供了一定依据和参考。

Release of HCl and H2S during pyrolysis of aged refuse derived-fuels

Based on the horizontal tubular reactor-chemical absorption together with TG-FTIR-MS methods, release characteristics of corrosive gases, viz., HCl and H₂S, during pyrolysis of refuse derived-fuels were investigated. The effects of pyrolysis temperature and pyrolysis type on their release behaviors for the aged (ARDF) and normal (NRDF) categories were compared. Meanwhile, the occurrence properties of corrosive elements (Cl and S) in solid products were also explored. The results indicate that the release of each corrosive gas has similar characteristic temperature range for slow pyrolysis of two categories. The release of HCl occurs at 200-400 and 420-500℃, respectively, while the emission of H₂S is observed at 230-370 and 380-670℃, respectively. In addition, ARDF has a lower emission amounts of both HCl and H₂S compared to NRDF under this condition. With regard to fast pyrolysis, the release of corrosive gases show different regularities, which largely depends on pyrolysis temperature. With increasing temperature, the emission of HCl and H₂S present a nonlinear and an increasing trends, respectively, reaching peak values at 850℃; It is 48.8% (ARDF) and 29.4% (NRDF) for HCl, 6.8% (ARDF) and 44.6% (NRDF) for H₂S. Subsequently, due to the distinctive release characteristics of corrosive gases, the occurrence of corrosive elements in solid phase relating to temperature differs in two categories. The retained amounts of Cl and S reach to 59.4% (450℃) and 84.3% (750℃) for ARDF, respectively. But for NRDF, that is 36.7% (850℃) and 15.2% (650℃), repetitively. It can be inferred that ARDF has the more stable corrosive elements difficult to be released into gases, which could provide some guidelines on thermal utilization of refuse derived-fuels.