Oil and gas producers face increasingly stringent sulphur plant emission requirements. The World Bank Standards call for SO2 emissions exiting an incinerator to be less than 150 mg SO2/Nm3. To meet these specifications, the vent air from sulphur degassing units should not be incinerated.

Shell Catalysts & Technologies has demonstrated that it is possible to avoid the emission of SO2 from the degasser by operating at a slightly elevated pressure. This enables reliable recycling to the sulphur recovery unit’s (SRU) front end. The new design relies on the well-proven process technology and long track record of the Shell sulphur degasser combined with process improvements to meet the new and more-demanding SO2 emission legislation.

Operating Shell’s sulphur degasser at an elevated pressure enables recycling of the vent gases to the front of the Claus sulphur recovery unit without the need for costly and low-reliability blowers. As is the case with all Shell Catalyst & Technologies’ hardware, our systems support compliance and profitability because of our owner/operator background.

It is a safe, robust and cost effective solution to help lower SO2 emissions. The addition of this technology to the Shell Catalysts & Technologies portfolio strengthens Shell’s ability to offer integrated solutions for gas processing, treating and sulphur recovery.

Employees calls in sulphur degassing results at a Shell plant

Shell’s sulphur degasser requires minimal operator oversight and functions without moving parts or catalysts.

Shell Catalysts & Technologies’ sulphur degassing process cuts the hydrogen sulphide and hydrogen polysulphide in the Claus liquid sulphur to less than 10 ppmv hydrogen sulphide compared with 250–300 ppmv in conventional sulphur pits. In this process, the sulphur is circulated over a stripping column, which is open at the top and bottom, by bubbling air through the sulphur. Agitating the sulphur in this way releases the hydrogen sulphide. The whole system is located in a separate vessel or in the intermediate sulphur storage.

Additionally, Shell Catalyst & Technologies’ sulphur degasser can be retrofitted into an existing pit or placed into a separate vessel entirely. This reduces implementation time and cost and is a result of its simple design. The simplicity of design is a common theme across our gas processing offerings.

Sulphur Recovery

Our reliable and robust operations with Claus, SCOT, sulphur degassing and THIOPAQ O&G sulphur recovery technologies secure gas production.

Natural Gas Technologies

Combining technical expertise with experience in upstream and downstream processes, we deliver fit-for-purpose designs as well as training and troubleshooting.