Causes and countermeasures of liquid sulfur system blockage in sulfur recovery unit

The 26 kt/a sulfur recovery unit of Shenhua Ningxia Coal Industry Group Coal Chemical Industry Branch Olefins Company has been put into use for more than five years, the liquid sulfur system-clogging problem has become more and more serious. The ways to deal with similar problems from the sulfur recovery unit of refinery, natural gas desulfurization plant and coal chemical industry were referenced. Reasons were analyzed from the aspects of the acid gas components, the problems existing in the operation and the process design faults. The following measures were taken to solve the problems: adding a heat regenerator cooler and a roots blower; prolonging the sweep time of sulfur from 2 days to 3 days when shut down; increasing the furnace temperature up to 1 060 ℃ when purging of sulfur; increasing the return line for the sulfur pump. These measures could solve the blocking problem of liquid sulfur system, which ensured the long-term safe and smooth operation of the unit.