NOx Removal from Catalytic Cracking Regenerator Effluent Gases in a Venturi Scrubber

摘要

Generally, one of the largest sources of air emissions in a refinery is the fluid catalytic cracking (FCC) unit. Its high-temperature flue gas contains NOx, SO_2, O_2, CO, CO_2, H_2O, and par-ticulate. In order to control particulate and SO_2, numerous FCC units already have Venturi scrubbers installed. This paper explores the feasibility of NOx removal from the catalytic cracking regenerator effluent gas by Venturi scrubber with sodium chlorite solutions. Various operating parameters were studied for their effects on NOx oxidation and absorption in the ejector Venturi scrubber. Experimental results showed that up to 90% of the NOx could be removed by the Venturi system, with a simultaneous 100% removal of SO_2. Experiments were also conducted using a feed with composition similar to that of effluent from a selective non-catalytic reduction pretreatment. The low concentration of NOx after the pretreatment can still be removed in the system, and solutions with very low concentrations of nitrate and chloride were generated, which is especially environmentally sound.