典型污泥与煤泥混合燃烧及硫氧化物释放特性

Co-combustion and sulfur oxide release characteristics of typical sludge and coal slime

污泥和煤泥产量逐年递增,影响生态环境和人类生活,急需对二者进行合理处置。结合污泥及煤泥的燃料特性,二者混烧能产生一定协同效果,在不同燃烧阶段有效互补,最终实现二者高效协同燃烧和综合减量化,对高效处置污泥与煤泥具有重要意义。前人大量研究了污泥/煤泥与典型燃料(煤、生物质等)的混合燃烧特性及硫氧化物释放特性,但鲜见二者之间的混烧特性及硫氧化物释放特性研究。因此在自主搭建的固定床燃烧反应系统上,对干燥后的1种典型污泥(达利污泥)以及2种煤泥(灵石煤泥和山西焦煤泥)进行了混合燃烧试验,分析了燃料种类、温度、混合比例等因素对混烧特性和硫氧化物释放特性的影响。结果表明:污泥与煤泥混合燃烧时,提高温度和增加污泥混合比例均能加快燃烧反应;燃烧过程中SO_(2)转化率随燃烧温度升高均呈先降低后上升的趋势,高温会促进固定在无机物中硫的二次释放。污泥与煤泥混合燃烧时,二者存在明显交互作用,会显著影响SO_(2)的生成与释放。800℃混烧时,由于灰分与SO_(2)形成含硫化合物加强了固硫作用,抑制了SO_(2)释放;而1000℃混烧时,由于加快燃烧反应促进了无机硫分解,从而导致SO_(2)释放增加。因此在800℃、30%污泥/70%煤泥掺混燃烧时,可获得较低的SO_(2)排放以及较高的燃料燃尽特性。

The output of sludge and coal slime is increasing year by year,which affects the ecological environment and human life,and it is urgent to deal with them reasonably.Combined with the respective fuel characteristics of sludge and coal slime,the co-combustion of the two can produce a certain synergistic effect and form an effective complementarity in different combustion stages,and finally realize the effi⁃cient co-combustion and comprehensive reduction of the two,which is of great significance for the efficient disposal of sludge and coal slime.The co-combustion characteristics and sulfur oxide release characteristics of sludge/coal slime and typical fuels(coal,biomass,etc.)have been studied,but there are few studies on the co-combustion characteristics and sulfur oxide release characteristics between the two.Therefore,on the self-built fixed-bed combustion reaction system,the co-combustion experiments were carried out on a typical dried sludge(Dali sludge)and two types of coal slimes(Lingshi coal slime and Shanxi coking coal slime)after drying.The influence mecha⁃nism of fuel type,temperature,mixing ratio and other factors on co-combustion characteristics and sulfur oxide release characteristics was analyzed.The results show that the combustion reaction can be accelerated by increasing the temperature and sludge mixing ratio when sludge and coal slime are mixed for combustion.During the combustion process,the conversion rate of SO_(2) firstly decreases and then in⁃creases with the increase of combustion temperature.High temperature can promote the secondary release of sulfur fixed in inorganic mat⁃ter.There is an obvious interaction in the co-combustion of sludge and coal slime,which will significantly affect the generation and release of SO_(2).At 800℃,the sulfur fixation is strengthened and the release of SO_(2) is inhibited due to the formation of sulfur-containing com⁃pounds between ash and SO_(2).However,when burning at 1000℃,the decomposition of inorganic sulfur is accelerated due to the acceler⁃ated combustion reaction,which leads to the increase of SO_(2) release.The experimental results show that the combustion with 30%sludge/70%coal slime mixture at 800℃can achieve lower SO_(2) emission and higher fuel burnout characteristics.