Project Case Study
Compressor Suction Scrubber
Oil and Gas Industry
5 Micron Mist Gas Separation
Liquid carryover shall not exceed 0.1 US gal/MMSCF (13.4 L/MMSCM), with 100% removal efficiency for droplets >10 microns..
Certified & High Capacity
PED, CE/UKCA & ATEX certified; for safe and efficient gas management.
Delivered in 10 Weeks
Strict timeline met by collaborating with suppliers to tailor equipment and integrate with existing infrastructure.
Overview
This project was for a client in the natural gas industry who required a suction scrubber for a gas compressor. At the compressor inlet, it is critical to remove liquids and fine mists from the gas to prevent damage to the compressor blades and to ensure efficient compression. The client’s specification was especially stringent: they wanted to limit liquid carryover to almost zero. The scrubber had to guarantee that any droplets larger than 10 µm were entirely removed and that overall liquid content was negligible (no more than 0.1 US gallons of liquid per million standard cubic feet of gas). Kapwell was tasked with designing a scrubber vessel meeting these high performance criteria, delivering it on a fast-track timeline of 10 weeks.
Solution
Kapwell delivered a vertical compressor suction scrubber designed with a combination of cyclonic and demisting technologies. Incoming wet gas enters a cyclonic inlet device that imparts a swirl, throwing out bulk liquids by centrifugal force. Following this, the gas passes through an internal mist eliminator (a high-efficiency coalescer) which captures the remaining fine droplets. This two-stage approach ensures that liquid carryover is virtually eliminated. The scrubber was sized to handle the gas flow while achieving the client’s performance spec: tests and calculations confirmed that liquid carryover would not exceed 0.1 US gal/MMSCF, and in fact droplets above 10 µm are 100% removed by the system. The unit was equipped with an automatic drain system to periodically purge collected liquids. Fabricated from robust materials, the scrubber can withstand the compressor suction pressure fluctuations and is built to code (ASME/PED). Kapwell also incorporated quick-opening access manways so that the internal elements can be inspected or replaced easily during maintenance.
Key
Features
Ultra-High Efficiency Separation
The scrubber achieves near-zero liquid carryover. It is guaranteed that liquid carryover ≤ 0.1 US gallons per MMSCF of gas, with 100% removal of droplets larger than 10 µm. This level of performance is critical for protecting compressors and is far superior to standard scrubbers.
Certified for Pressure and Hazardous Service
The unit is built in compliance with PED (Pressure Equipment Directive) and marked CE/UKCA, and it also meets ATEX requirements for operation in potentially explosive gas areas. These certifications demonstrate that the scrubber adheres to the highest safety and quality standards, giving the client confidence in its operation.
Fast-Track Fabrication
Kapwell completed the design, fabrication, and testing of the scrubber in just 10 weeks. This rapid turnaround was possible due to modular design practices and efficient project execution. It highlights Kapwell’s ability to meet urgent client timelines without sacrificing quality.
Advanced Internals & Drains
Inside the scrubber, the combination of a cyclonic separator and a fine mist eliminator ensures multi-layered protection. The internal design maximizes dwell time and separation forces. Additionally, a reliable automatic draining system removes separated liquids to a blowdown line, preventing any re-entrainment. The scrubber’s internals were custom-designed based on Kapwell’s extensive experience in mist elimination, ensuring they hit the required performance mark on the first try.
Challenges & Innovation
The primary challenge was the very stringent performance requirement. Achieving 100% removal of >10 µm droplets and virtually no carryover required innovation beyond conventional scrubber designs. Kapwell employed CFD analysis and custom-designed internals to meet this challenge, innovating particularly on the mist eliminator element – selecting a high-performance vane type or fiber bed that could handle high gas velocity while capturing fine mist. The other challenge was the extremely short timeline (10 weeks). To address this, Kapwell utilized its in-house fabrication capabilities and parallel workflows (design, material procurement, and fabrication overlapped) to accelerate the schedule. An innovative project management approach and pre-approved materials allowed the team to compress what is typically a much longer lead time. The result was a scrubber delivered on time that still met all the client’s specs, showcasing Kapwell’s agility and technical prowess.
Client Benefit
Compressor Protection
The client’s compressor is now fully protected from liquid ingestion. Even under upset conditions, no large droplets will reach the compressor. This vastly reduces the risk of compressor damage or downtime, extending the compressor’s lifespan and maintaining its efficiency.
Operational Reliability
With virtually dry gas at the compressor inlet, the compression process is more reliable and predictable. There are no sudden surges or vibrations caused by liquid slugs, which means smoother operation and less wear-and-tear on moving parts.
Safety and Compliance
The scrubber’s certified design (PED, CE/UKCA, ATEX) ensures that the equipment meets all regulatory requirements, which simplifies the client’s compliance documentation. It also means the scrubber can be used in international projects. The high separation efficiency improves safety by reducing the likelihood of flammable liquids accumulating in the system.
Quick Implementation
The ability of Kapwell to deliver the scrubber in 10 weeks meant the client could implement their compression project without delay. This prevented costly schedule slips and allowed them to ramp up gas compression operations as planned. The fast delivery, combined with the high performance, provided a swift and significant return on investment for the client.
Timeline
Delivered in 16 weeks. This project was executed on an accelerated schedule from design through delivery. By the tenth week, the scrubber was built, tested, and shipped to the client’s site, aligning perfectly with the compressor installation timeline.