摘要
阴燃是一种新型低热值有机固废热处理技术,针对污泥的阴燃灰渣特性开展污泥自持阴燃试验,以期为污泥的阴燃处置技术推广提供关于灰渣处置的技术支持。利用自制阴燃台架,含水率50%污泥在空气达西流速3.5 cm/s、污泥/沙掺混比1∶4的条件下进行自维持阴燃试验。通过阴燃温度曲线图解析了污泥自持阴燃处置的过程特性,并根据温度曲线对失重及质量变化速率进行计算分析。通过同时开展污泥在1000℃的燃烧以及500℃的热解试验,分别收集燃烧灰、热解焦,利用BCR逐级提取法对阴燃灰、燃烧灰、热解焦中的常量元素(Na、K、Mg、Ca、Al、Fe、P)和痕量重金属元素(Zn、As、Cr、Cd、Pb、Ni、Cu)的赋存形态进行对比解析。研究发现,自持阴燃过程可以划分为4个阶段:预热、引燃、自持阴燃、燃尽;试验过程最高温度为引燃阶段底部物料燃烧峰值温度678℃,自持阴燃过程平均温度517℃;自持阴燃过程燃烧面平均传播速率为0.37 cm/min,平均质量变化速率为10.41 g/min;阴燃灰中主量无机矿物元素为Si,主要痕量重金属元素为Zn、Pb、Cr;阴燃灰、热解焦、燃烧灰中Na、K、Al、Fe、P以及As、Cr、Cd、Pb主要以残渣态形式存在,同时,阴燃灰中Na、K、Mg以及Ca、Zn、As、Ni酸可溶态含量比热解焦和燃烧灰高,对于污泥阴燃、热解、燃烧处置后固体产物的处理及利用应对元素的不同赋存特点予以区分。
Smoldering is a new type of low calorific value organic solid waste heat treatment technology.According to the characteristics of sludge smoldering ash,the self-sustaining smoldering test ofsewage sludge(SS)was carried out to provide technical support for the promotion of smoldering disposal technology of SS.Based on a lab-scaled smouldering reactor,self-sustaining smoudering of SS was achieved with parameters of 50%water content of SS,3.5 cm/s of air Darcy flow rate,(wet)SS and sand mixing ratio of 1∶4.The process characteristics of SS self-sustaining smoldering treatment were analyzed by smoldering temperature curve.The mass lose profile was also calculated based on the temperature records and the basic properties of the raw SS.To compare with combustion and pryolysis,the SS was also sent to burn at 1000℃and pryolyzed at 500℃,followed by collection of the smouldering ash(ASH-1),combustion ash(ASH-2),and pryolysis produced char(CHAR).BCR sequential extraction method was then applied to study the occurrence forms of major elements(Na、K、Mg、Ca、Al、Fe、P)and trace elements(Zn,as,Cr,Cd,Pb,Ni,Cu)in the three residue samples.The study shows that the smouldering treatment can be divided into four periods:preheating,ignition,self-sustaining smouldering,and extinguishing;the highest temperature is 678℃of the bottom material combustion peak temperature in the ignition stage,and and the average temperature of the self-sustaining smoldering process is 517℃.The median moving rate of burning front is 0.37 cm/min,and the average mass losing rate is 10.41 g/min during self-sustaining smouldering;the dominating mineral element in ASH-1,ASH-2,and CHAR,is Si,and the main trace elements are Zn,Pb,and Cr;Na,K,Al,Fe,P,and As、Cr、Cd、Pb in the three residues are dominated in residue form;the content of acid soluble form of Na,K,Mg,Ca,and Zn,As,Ni in ASH-1 are higher than those in ASH-2 and CHAR.Therefore,the further disposal of ASH-1,ASH-2,and CHAR in practice should take the differences of the occurrence forms
作者
成明锴
李琛
付建红
冯超
徐明厚
乔瑜
CHENG Mingkai;LI Chen;FU Jianhong;FENG Chao;XU Minghou;QIAO Yu(State key laboratory of coal combustion,Huazhong University of Science and Technology,Wuhan 430074,China)
出处
《洁净煤技术》
CAS
2020年第5期166-172,共7页
Clean Coal Technology
基金
国家自然科学基金资助项目(51976068)
国家重点研发计划资助项目(2018YFC1901201)。
关键词
污泥
阴燃
矿物元素
痕量元素
逐级提取分析法
sewage sludge
smouldering
mineral element
trace element
sequential extraction
