ABSTRACT

With the development of urbanization and industrialization, vast plenty of sewage sludge was produced. Incineration has been becoming the mainstream disposal method due to its many advantages. However, the problem of fine particulate matter produced from the incineration process made a restriction on the development of this method. In this study, the effects of temperature, particle size, and calcium-based additives (CaO) on the generation characteristics and micrographs of fine particulate matter were investigated via a lab-scale fluidized bed. The results revealed that the fine particulate matter showed a bimodal distribution and the two peaks was located at around 0.5 μm and 5 μm, respectively. With the increasing of temperature from 750°C to 950°C, the mass concentration of PM_0.5 increased by 12.88 mg/g, while PM₅ increased by 57.79 mg/g, which indicated as the temperature increases, the crushing degree of minerals and coke particles is more intense, which further leads to an increase in the amount of fine particles. The number of fine particles increased when the feed size getting smaller, which showed an intense link to the feed size. That was because the smaller the particle size, the more severe the degree of crushing, and the greater the number of fine particles formed after crushing. Furthermore, the results also found that CaO can be used as a good binder between particles to promote the growth and agglomeration of fine particles and inhibit the generation of fine particles. When the additive ratio was 3%, 6%, and 9%, the mass concentration of PM_0.3 decreased by 53.7%, 63.5%, and 86.1%, while the mass concentration of PM₃ decreased by 43.9%, 74.7%, and 91.7%. Therefore, CaO can be used to reduce the production of fine particles in practical engineering applications.

摘要

随着城市化和工业化的发展，产生了大量的污水污泥。由于其许多优点，焚化已成为主流处理方法。然而，由焚化过程产生的细颗粒物质的问题限制了该方法的发展。在这项研究中，通过实验室规模的流化床研究了温度，粒度和钙基添加剂（CaO）对细颗粒物的产生特性和显微照片的影响。结果表明，细颗粒物呈双峰分布，两个峰分别位于0.5μm和5μm附近。随着温度从750°C升高到950°C，PM _0.5的质量浓度随着温度的升高，PM ₅增加了12.88 mg / g，而PM ₅增加了57.79 mg / g，矿物和焦炭颗粒的破碎度更加强烈，这进一步导致细颗粒的数量增加。当进料尺寸变小时，细颗粒的数量增加，这与进料尺寸密切相关。这是因为粒度越小，粉碎程度越严重，粉碎后形成的细粒数量越多。此外，结果还发现CaO可以用作颗粒之间的良好粘合剂，以促进细颗粒的生长和附聚并抑制细颗粒的产生。当添加比例为3％，6％和9％时，PM _0.3的质量浓度分别降低了53.7％，63.5％和86.1％，而PM ₃的质量浓度分别降低了43.9％，74.7％和91.7％。因此，在实际工程应用中，CaO可用于减少细颗粒的产生。