Tail Gas Treating Technologies to Meet Ultra-low SO2 Emission Standards

The requirement to meet ultra-low SO2 emission standards, even lower than World Bank limits, is becoming more and more prevalent for new refinery and natural gas developments and/ or certain regions. At the same time, more-complex, sour gas fields are being developed as sweet fields become depleted, and in the oil sector crudes are also becoming heavier and more sour.

Addressing these challenges while ensuring that increasingly stringent SO2 emission limits are met in the future, requires technology capable of ultra-high levels of sulphur recovery, even when dealing with difficult gas streams. Next to meeting the increasingly stringent SO2 emission limits, proposed technology should also satisfy the requirement of lowest life-cycle cost. In this respect, Shell Catalysts & Technologies is continuously developing and/ improving its portfolio of gas treatment technologies.

Technologies Tailored Toward Your Objectives

Shell Catalysts & Technologies has utilised its extensive knowledge and experience of designing and operating Shell Claus off-gas treating (SCOT) units since the 1970s to hone the technology for this purpose. The company has also extended its tail gas treating portfolio with the addition of the Shell CANSOLV TGT+ technology and the development of the next generation SCOT ULTRA technology to give even further flexibility for operators to achieve the perfectly tailored solution to their processing needs and objectives.

Shell CANSOLV TGT+ technology can be part of an integrated sour gas treating solution, enabling ultra-low SO2 emissions and the capture up to 99.99% of the overall sulphur present in sour gas streams while minimising the complexity of the process line-up. This system sits at the back end of the gas processing line-up and serves as the final destination to capture SO2 from all the plant’s sour gas streams routed to the incinerator.

SCOT ULTRA employs sharper design rules, improved catalyst technology and a new advanced proprietary JEFFTREAT-ULTRA solvent. The new technology lowers operating costs, achieves higher performance in warmer climates, and improves resilience to process changes and upsets. The technology can be retrofitted to existing tail gas units as well as new grassroots applications.

Shell Catalysts & Technologies has licensed more than 300 SCOT units, which has enabled the team to build up a strong background in using tail gas treating for meeting SO2 emission limits. As both a designer and an operator of these units, Shell is well equipped with the knowledge and expertise necessary to get the best results and offers more than just a design and delivery service.

Employees meeting at the Groundbirch asset discussing tail gas treatment operations

Our emission reduction results frequently meet and surpass World Bank limits.

Shell’s unique position as both operators and licensors of the technology we use is demonstrated in our tail gas treating solutions. Shell Claus off-gas technology (SCOT), Shell CANSOLV* TGT technology, SCOT Ultra, and the Shell CANSOLV SO2 Scrubbing System are just a shortlist of services we trust and employ ourselves and for our partners depending on their unique requirements.

Legislation by the World Bank, the International Maritime Organization (IMO), and other legislative bodies become more environmentally and sustainability-focused every year. Capitalise on the wide range of proven Shell Catalysts & Technologies’ solutions accompanied by our expertise and partnership for optimal results.

Claus Off-Gas Treating (SCOT) Process

Refineries have lowered operating costs and extended cycle lengths by installing our technologies and catalysts in Claus tail-gas treating units.


Gas absorptions solutions that help meet product specifications and restrictive emissions limits within a lower cost structure.

Contact Shell Catalysts & Technologies

Contact Shell Catalysts & Technologies to meet the challenges petrochemical plants face with confidence.