Technical Retrofit For No_x Treatment In Regeneration Flue Gas Of Heavy Oil FCC Unit

Fluid catalytic cracking(FCC)is one of the important methods used to convert the heavy oil into light oil in refineries,and is also the main source of NOx,which accounts for about 50%of total NOx emission of oil refinery.There is a strong reducing atmosphere in partial burn FCC regenerator,so its NOx content in flue gas is relatively low,but with the more and more strictly emission standard on the FCC flue gas,the NOx emissions of partial burn regeneration of FCCU are also facing increasing pressure.The NOx generation and transformation of FCC process is a complex process associated with many factors.In this paper,the sources of NOx generation in the Guangdong RFCC are investigated in detail,and the improving scheme of NOx treatment technology is discussedVarious existing control technologies that might be applicable to NOx emissions from incompletely regenerated FCC units were analyzed and compared in this paper.Due to company site and environmental constraints,it was impossible to change the regenerator structure and operation mode.There was no condition either for buildding new heavy oil hydrotreating pretreatment equipment or large-scale upgrading the devices to equip SCR or LoTOx.The most feasible technical approach at present was to utilize the catalytic aid technology to remove NOx from the flue gas.Through the analysis of the operation of the heavy oil catalytic cracking unit regenerator of the company,several formulas of denitration catalysts were developed.After parallel test,the TUD-DNS ODEP denitration catalyst was selected because of its higher denitrification conversion rate and less influence on product distribution.At last,the operating parameters were optimized as wellThe industrial application indicates that the concentration of NOx has dropped from 210 mg/Nm3 to 110 mg/Nm3 and the removal rate was about 48%when the TUD-DNS ODEP was 2.54%of the catalyst inventory,which have reached the industry pollutant emission standard The application of TUD-DNS ODEP does not adversely affect the operation of RFCC,the yield of major product,the quality of major products and the quality of the catalyst,which has achieved the goal of technological transformation.At the same time,The application of TUD-DNS ODEP solves the problem of NOx emission of RFCC unit of a petrochemical company in Guangdong Province,and fills the application gap of denitration aid for incompletely regenerated catalytic cracking unit...