Abstract:

In order to maintain the stable state of liquid sulfur, the liquid sulfur storage equipment of sulfur recovery unit needs to be equipped with steam coil type heat tracing system. The coil is arranged at the bottom of sulfur pit or liquid sulfur storage tank. It can be divided into straight pipe type and coil type according to its structure, and there are slight differences in the processing and manufacturing methods and heat exchange area of the two structural types. Sulfur pit belongs to micro negative pressure equipment, and there is a small amount of highly toxic hydrogen sulfide between the liquid sulfur level and the cover plate of sulfur pit. Therefore, the steam coil passing through the cover plate needs to be sealed to avoid toxic gas leakage, and the sealing methods can be divided into secondary concrete pouring, flange cover and direct burial. There are S, SO₂, SO₃ and H₂O in the sulfur pit. According to different operation conditions and gas-liquid phase space, three different corrosion environments are generated, and different materials are selected for the steam inlet pipe, condensate outlet pipe and steam coil in different corrosion environments.

Key words: sulfur pit, steam coil, liquid sulfur, sulfur recovery, seal