Zhou Ao, Ma Wenjing, Ruan Renhui, Yu Shilin, Tan Houzhang, Deng Shuanghui, Liang Kun, Liu Kai, Han Donglin, Wang Xuebin
MOE Key Laboratory of Thermo-Fluid Science and Engineering, Xi'an Jiaotong University, Xi'an, 710049, China.
MOE Key Laboratory of Thermo-Fluid Science and Engineering, Xi'an Jiaotong University, Xi'an, 710049, China.
J Environ Manage. 2022 Mar 8;311:114863. doi: 10.1016/j.jenvman.2022.114863.
With the increasing production of municipal sewage sludge (MSS) in China every year, the co-firing of MSS and pulverized coal is getting more and more widely applied in large coal-fired power plants. The co-firing of MSS and pulverized coal will produce a large amount of particulate matter (PM) emissions, especially submicron particles. In this paper, the formation characteristics of submicron particles in the co-firing process of coal and MSS were studied in a drop tube furnace. The influence of the furnace temperature and the addition ratio of sludge on the particle size distribution and element composition of submicron particles in MSS, pulverized coal combustion and co-firing was mainly studied. The experimental results show that the furnace temperature has an influence on the formation of PM. For sludge combustion, increasing the furnace temperature will promote the formation of PM. The main reason is that increasing the furnace temperature promotes the gasification of Si, S, Fe, and P to form the precursor of PM or PM. At same furnace temperature, the volume concentration and mass concentration of PM produced from pulverized coal combustion are less than that of sludge. Different from sludge combustion, co-firing of pulverized coal and sludge has a synergistic effect on eliminating PM formation. Increasing the addition ratio of sludge can decrease the volume concentration and mass concentration of PM. This is because that aluminosilicates formed during co-firing promotes the scavenge Si, Ca, Fe, thereby reducing the precursors of PM and the mass yield of PM. Increasing the furnace temperature in co-firing can inhibit the formation of PM. When the furnace temperature is between 1100 °C and 1300 °C, increasing the furnace temperature will reduce the Fe content and increase the content of Si, Ca, Na, K, and P in PM. However, the reduction of Fe and the increase of Si, Ca, Na, K, and P in PM offset each other, resulting in an insensitive relationship between the mass yield of PM and the furnace temperature.
随着中国城市污水污泥（MSS）年产量的不断增加，MSS与煤粉的混烧在大型燃煤电厂中得到越来越广泛的应用。MSS与煤粉混烧会产生大量颗粒物（PM）排放，尤其是亚微米颗粒。本文在沉降炉中研究了煤与MSS混烧过程中亚微米颗粒的形成特性。主要研究了炉温及污泥添加比例对MSS、煤粉燃烧及混烧中亚微米颗粒粒径分布和元素组成的影响。实验结果表明，炉温对PM的形成有影响。对于污泥燃烧，提高炉温会促进PM的形成。主要原因是提高炉温促进了Si、S、Fe和P的气化，形成了PM或PM的前驱体。在相同炉温下，煤粉燃烧产生的PM体积浓度和质量浓度小于污泥。与污泥燃烧不同，煤粉与污泥混烧对消除PM形成具有协同作用。增加污泥添加比例可降低PM的体积浓度和质量浓度。这是因为混烧过程中形成的铝硅酸盐促进了对Si、Ca、Fe的清除，从而减少了PM的前驱体和PM的质量产率。混烧时提高炉温可抑制PM的形成。当炉温在1100℃至1300℃之间时，提高炉温会降低PM中的Fe含量，增加Si、Ca、Na、K和P的含量。然而，PM中Fe的减少与Si、Ca、Na、K和P的增加相互抵消，导致PM质量产率与炉温之间的关系不敏感。
