Abstract: A sulfur recovery unit has been shut down for maintenance. This paper provides an in-depth analysis of the key steps and technical improvement and environmental protection management in the shutdown process. It discusses in detail the main challenges in the shutdown process including the delay of system sulfur blowing, insufficient passivation depth of the ammonia reactor, and excessive steaming tower time. Aiming at these problems, the paper proposes such solutions as optimizing the passivation operation of the hydrogenation reactor, upgrading the steam tower process and improving the cleaning efficiency of the liquid sulfur pool. Through technological upgrading and management optimization, the green shutdown of the sulfur recovery unit will develop in a more environmentally friendly and efficient direction to promote the sustainable development of enterprise.

Key words: sulfur recovery unit, shutdown for overhaul, SO2 emission control, hydrogenation catalyst passivation, green shutdown, technical improvement