颗粒物(PM)作为主要的空气污染物,一般包括可过滤颗粒物(FPM)和可冷凝颗粒物(CPM)。CPM最近逐渐引起了广泛的关注,由于其在总PM排放中的比例不断增加。流化催化裂化(FCC)装置,炼油厂的主要排放源,大多采用湿法烟气脱硫(WFGD),这将产生大量的CPM。然而,FCC装置的CPM排放和组成实际上尚不清楚。在这项工作中,我们旨在了解FCC烟气中CPM的排放特性,并提供一些潜在的控制策略。这里,进行了三个典型的FCC单元的堆栈测试,以监测FPM和CPM,并且现场监测的FPM结果高于连续排放监测系统(CEMS)提供的浓度。CPM的排放浓度为28.88至86.17mg/Nm3,分为无机部分和有机部分。无机组分主要由CPM组成,其中水溶性离子包括SO42-,Na+,NH4+,NO3-,CN-,Cl-,F-,是主要的贡献者。此外,多种有机化合物被检测为CPM中有机组分的定性分析,可以大致分为烷烃,酯类,芳烃,和其他人。最后,在了解CPM特点的基础上,我们提出了两种控制CPM的策略。这项工作有望促进FCC装置中的CPM排放调节和控制。
Particulate matter (PM) as a major air pollutant, generally includes filterable particulate matter (FPM) and condensable particulate matter (CPM). CPM has gradually attracted widespread attention recently, due to its increasing proportion in total PM emissions. Fluid catalytic cracking (FCC) units, the main emission source in refineries, mostly use wet flue gas desulfurization (WFGD), which will produce a large amount of CPM. However, CPM emission and composition of FCC units are actually unclear. In this work, we aimed to understand the emission characteristics of CPM in FCC flue gas and provide some potential control strategies. Here, the stack tests of three typical FCC units were conducted to monitor FPM and CPM, and the field monitoring FPM results are higher than the concentration provided by Continuous Emission Monitoring System (CEMS). The emission of CPM is at a high-level concentration from 28.88 to 86.17 mg/Nm3, divided into inorganic fraction and organic fraction. The inorganic fraction is mainly composed in CPM, where water-soluble ions including SO42-, Na+, NH4+, NO3-, CN-, Cl-, and F-, are the major contributors. Moreover, a variety of organic compounds are detected as qualitative analysis of organic fraction in CPM, which can be roughly classified into alkanes, esters, aromatics, and others. Finally, on the basis of the understanding of the characteristics of CPM, we have proposed two strategies for CPM control. This work is expected to advance CPM emission regulation and control in FCC units.