脱硫脱硝装置外排水氨氮超标原因分析

CAUSE ANALYSIS ON THE EXCESSIVE AMMONIA NITROGEN IN THE WATER DRAIN FROM THE DESULPHURIZATION AND DENITRATION DEVICE

中石化武汉分公司的两套催化裂化装置于2014年12月新建了烟气脱硫脱硝装置脱硫脱硝装置运行以来,外排烟气中的氮氧化物、二氧化硫、粉尘及外排废水中的固体悬浮物、化学需氧量、pH均能达标排放,但外排废水中氨氮含量一直出现超标问题,加大了水务车间生产负荷对外排水氨氮超标原因进行了分析,通过排除法得出,催化裂化再生烟气中携带氨气是导致脱硫脱硝装置外排水氨氮超标的直接原因,通过外排废水中氨氮含量反推计算得出,武汉石化2号催化裂化装置再生烟气中的氨气含量约为81.04 mg/m^3。

New flue gas desulphurization and denitration devices were built in two sets of catalytic cracking units in SINOPEC Wuhan Company in December 2014.Since the operation of the desulphurization and denitration device,discharge of nitrogen oxides,sulfur dioxide in flue gas,dust and suspended solid,chemical oxygen demand(cod),pH in the wastewater could be discharged to reach the standards,but the ammonia nitrogen content in the discharged wastewater has been excessive,increasing the production load of water workshop.This paper analyzed the causes for the excessive ammonia nitrogen in the discharged wastewater.Through exclusion method,it was concluded that the excessive ammonia nitrogen in the water drain from the desulphurization and denitration device was directly caused by the ammonia carried in the regeneration flue gas from the catalytic cracking unit.By adopting inverse calculation of the ammonia nitrogen content in the discharged wastewater,it was concluded that the ammonia content in the regeneration flue gas from the No.2 catalytic cracking unit of Wuhan Company was about 81.04 mg/Nm^(3).