PTQ Q3 2025 Issue

173

500 550 600

145 159

130

450

+59%

400

116

Base case

100

350

300

Corrected dry gas water content (ppmv) Gas ow through contactor

250

0 50 100 200 150

0 29 14 43

13-Oct

14-Oct

15-Oct

16-Oct

17-Oct

18-Oct

19-Oct

20-Oct

Figure 6 Demonstrated throughput increase after an STT revamp of a TEG dehydration column

Advancing TEG dehydration TEG dehydration columns have traditionally relied on struc- tured packing, with earlier designs using bubble cap trays. In the 1990s, the introduction of swirl tube trays helped reduce contactor footprint while maintaining or improving dehydration efficiency. However, excessive glycol losses, ranging from 0.2 to 1 US gallon/MMSCF (30-200 L/MSm³), highlighted the challenges of liquid carryover in compact dehydration systems. With the introduction of STT, operators now have an effective solution to minimise glycol losses and enhance separation efficiency. The system, combined with a mesh– swirl deck–mesh (MSM) demisting system, achieves up to 99% separation efficiency, significantly reducing gly - col losses through mechanical entrainment. This enables operators to meet industry standards of 0.1 US gallon/ MMSCF (15 L/MSm³) while improving overall dehydration performance. One of the key advantages of STT is its ability to increase gas throughput within a given contactor diameter, making it a viable retrofit solution. By enhancing capacity with - out major equipment modifications, operators can achieve lower capex, reduced carbon footprint and lower operational expenditure, while accelerating project timelines. Deployed in 2021 at a gas gathering station, STT was used to upgrade an existing 96.5in (2.45m) diameter glycol contactor originally fitted with structured packing. The ret - rofit incorporated seven STT trays and an MSM separation system, with no other major changes to the glycol unit. The result was a 45% increase in production capacity, raising out - put from 346 to 500 MMSCFD. During testing, the operator requested a further flow rate increase, successfully reaching 550 MMSCFD (59% increase), which was sustained for eight hours before reverting to the designed rate (see Figure 6 ). Value to operators Throughout testing and operation, no noticeable glycol losses were observed, and since its deployment, no abnor- mal TEG losses have been reported. Operators have noted that glycol losses are lower compared to structured packing,

reinforcing the long-term reliability of STT technology, which delivers a range of benefits that can enhance efficiency and reduce costs. For example, it can help: • Enhance mass-transfer efficiency by improving gas– liquid contacting and separation on each tray, which can significantly reduce column size or increase gas treatment throughput by up to 20% compared to the latest-generation structured packing trays. • Suppress foaming by using high-efficiency swirl tubes to improve vapour disengagement, helping to reduce solvent foaming. • Increase operational flexibility by accommodating fluctua - tions in gas and liquid flow rates, making it easier to respond to changing demand. • Simplify installation with smaller column dimensions that make transportation and installation easier, particularly in remote locations with limited access to cranes and heavy-lift- ing equipment, helping to reduce costs. Conclusions STT can help optimise column hydraulics and mass trans- fer in AGRUs and TEG dehydration columns, offering a step-change in efficiency. Their design enables co-current gas and liquid contact on each tray, allowing for smaller, more cost-effective absorbers in new projects or increased throughput in brownfield applications. Extensive testing and real-world deployment have shown how STT can reduce absorber costs by up to 50% and debottleneck existing units, enabling operators to handle higher contaminant loads without compromising performance. Sulfinol is a Shell trademark. Anh Do Thi Viet is the Licensing Technology Manager for Shell Turbo Technologies at Shell Catalysts & Technologies, where she oversees global commercialisation. She is based in Amsterdam, the Netherlands. Ton Schlief is a Senior Gas Processing Engineer at Shell Global Solutions B.V., based in Amsterdam, the Netherlands. Karl Stephenne is a Senior Gas Processing Integration Engineer at Shell Canada, based in Montreal, Canada.

PTQ Q3 2025