Catalytic Cracking (FCC) Unit Flue Gas Desulfurization And Denitration Technology Overview

Environment pollution cause by SOx and NOx emission in the flue gas from FCCU is paid more and more attention. According to the government’s "Five-Year Plan",it’s a imperative task to control SOx and NOx emission of FCCU.Application of desulfurization and denitrification technology is still in the primary stage in China,so the the related technology have been in enginnering application are come from foreign countries.This papers research on desulfurization and denitrification technology for FCC flue gas.Based on the formulation of SOx and NOx in the regenerator of FCCU, the main desulfurization and denitrification technology for FCC flue gas which include wet scrubber, LOTOx,SCR, SNOx,LOTOx/EDV was studied in this work.Moreover, comparison&analys of these technology’s technical characteristics,application status operation have been made,the conclusions are as follows:(1) There are two effective measures to make reduction of SOx,NOx emission to help the flue gas treatment system more economics,one is catalytic hydrogenation for the raw oil, another is add SOx and NOx additives for reducing catalytic removal of sulfur, nitrogen content in the raw oil.(2)The advantages of wet flue gas desulfurization technology are high removal efficiency as95%, reliability and easy operation, but the another hands,optimization still need because it’s high operation consumption like water, power plant and ddesulfurizing agent lead to high operation cost.(3)For the consideration of efficiency and economy,SCR will be the suitable DeNOx process for FCC flue gas.But attention will be paid to the required reation temperature(320～400℃) and special requirement for SCR catalyst.(4)Combination of wet scrubber and SCR could be the best choice for FCC flue gas’s NOx and SOx emission control.The combinated techonology is worthy of promotion in China. The future research on and NOx control for FCC flue gas will be the recycling of SOx from wet scrubber, optimization of regenerator design and operation,low temperature catalyst for SCR and more economic technology.