School of Electrical and Power Engineering, Taiyuan University of Technology, Taiyuan 030024, Shanxi, China.
State Key Laboratory of Coal Combustion, Huazhong University of Science and Technology, Wuhan 430000, Hubei, China.
Sci Total Environ. 2022 Dec 10;851(Pt 1):158166. doi: 10.1016/j.scitotenv.2022.158166. Epub 2022 Aug 18.
Co-combustion of sewage sludge (SS) and coal slime (CS) is a promising method to achieve resource utilization of both solid wastes. However, the emission characteristics of NO/SO and the interaction mechanisms between SS and CS are unclear. In this paper, the co-combustion characteristics and NO/SO emission behavior of SS and CS were investigated using a thermogravimetric analyzer and a tube furnace combustion system, and the interactions between SS and CS were explored. The results revealed the presence of remarkable interactions between SS and CS during the co-combustion. For the combustion characteristics, non-catalytic factors (interaction between volatiles and heat synergy) and catalytic factors (catalysis of inorganic components) controlled the combustion stage of the heavy volatiles and fixed carbon of the blends, respectively, leading to an earlier combustion process. For NO and SO emission characteristics, SS-CS co-combustion had significant NO in-situ reduction and self-desulphurization characteristics at 800 °C and 900 °C. The best inhibition occurred at 900 °C and 50 % CS ratio, and NO and SO emission amounts were reduced by 0.25 mg/g and 1.37 mg/g, respectively, compared to the theoretical values. At 1000 °C, co-combustion promoted the emissions of both NO and SO. The interaction mechanisms suggested that the reducing atmosphere created and the reducing gases released by SS combustion promoted the reduction of CS-NO, while the char formed by CS exhibited a significant reduction of SS-NO. In addition, the effect of CS addition on the mass transfer process enhanced the sulfur fixation of inorganic components in SS, which led to the suppression of SO production. These findings provide a better understanding of the interactions between SS and CS during SS-CS co-combustion.
污水污泥 (SS) 和煤泥 (CS) 的共燃烧是实现这两种固体废物资源利用的有前途的方法。然而，NO/SO 的排放特性以及 SS 和 CS 之间的相互作用机制尚不清楚。本文采用热重分析仪和管式炉燃烧系统研究了 SS 和 CS 的共燃烧特性和 NO/SO 排放行为，并探讨了 SS 和 CS 之间的相互作用。结果表明，SS 和 CS 共燃烧过程中存在显著的相互作用。在燃烧特性方面，非催化因素（挥发分与热协同作用的相互作用）和催化因素（无机成分的催化作用）分别控制了混合物重挥发分和固定碳的燃烧阶段，导致燃烧过程提前。对于 NO 和 SO 的排放特性，SS-CS 共燃烧在 800°C 和 900°C 时具有显著的原位还原和自脱硫特性。在 900°C 和 50%CS 比例下，NO 和 SO 的排放量分别减少了 0.25mg/g 和 1.37mg/g，与理论值相比。在 1000°C 时，共燃烧促进了 NO 和 SO 的排放。相互作用机制表明，SS 燃烧产生的还原气氛和释放的还原气体促进了 CS-NO 的还原，而 CS 形成的焦则显著还原了 SS-NO。此外，CS 添加对传质过程的影响增强了 SS 中无机成分的硫固定，从而抑制了 SO 的生成。这些发现为更好地理解 SS-CS 共燃烧过程中 SS 和 CS 之间的相互作用提供了依据。
