TGTU is one of the most versatile units in sulphur complex that will help in achieving sulphur recovery up to 99.9% and reduce the SO2 emission to the atmosphere. This units usually consist of various equipment and piping which are typically made in carbon steel and stainless-steel metallurgy.
The material of construction made of carbon steel are seriously getting impacted due to unpredictable upset from the upstream unit (SRU-Sulphur Recovery Unit). This upset is uncontrollable and will result in various damages to the carbon steel components in the form of fouling, pitting, thinning and cracking damage mechanism. Upgradation of carbon steel to stainless steel material will be capable to withstand various upset and heavy unit loads.
This unit requires proper control on various process parameters such as pH, Ammonia Concentration, Caustic Strength, Type of Water, Temperature, TSS, SO2, H2S and Iron to prevent any corrosion issues.
The corrosion issues in this unit will results in various consequences subject to health, safety, environmental, economic impact, and damage to company assets including reputation. The units required high attention subject to material selection, cost optimization, in-service inspection methodology and control over operating process parameters. This paper will describe all the factors in details that will help in mitigating the corrosion challenges in TGTU and provides the cost comparison subject carbon steel versus stainless steel material in this application.