Gas Dehumidifier
Reliable, Efficient, and Compact Biogas Dehumidification for Power & Process Applications
.svg)
Dew point control for clean, dry gas delivery
CRA’s Biogas Dehumidifier is designed to deliver clean, dry biogas by removing excess moisture before it reaches engines, boilers, or other critical equipment. Designed as a skid-mounted unit with integrated cooling, separation, and drainage, it protects against corrosion, improves combustion efficiency, and extends the life of downstream systems. Compact and robust, it is built to hold a consistent outlet dew point for power generation and industrial use.
Outlet Dew Point
Lowered by refrigerated cooling
Process
Refrigeration-based cooling
Condensate Removal
Automatic
Configuration
Skid-mounted
What is a Gas Dehumidifier?
A biogas dehumidifier lowers the moisture content of raw or partially treated biogas by cooling the gas stream below its dew point, causing water vapour to condense and drain away before the gas reaches compressors, upgrading systems, or combustion equipment.
How it works
Biogas cools below its dew point inside a refrigerated heat exchanger, causing water vapour to condense out before the gas continues downstream.
Biogas enters a refrigeration-cooled heat exchanger, where its temperature drops below the dew point.
Condensed water separates out in an integrated knock-out vessel.
An automatic drain discharges the condensate, and dry gas exits at a consistent, controlled dew point.
Key Benefits
All components skid-mounted for easy installation, transport, and plug-and-play operation
Removes moisture to prevent corrosion, wear, and costly downtime in engines and boilers
Delivers drier gas that burns cleaner, supporting stable and efficient power generation
Engineered with rugged design and advanced controls for landfill, AD, and utility conditions
Automatic drainage, durable materials, and simple operation minimise service needs
Projects That Push Boundaries
Prevents corrosion and combustion instability in biogas systems exposed to desert heat.
The CRA Edge
30+ years of gas processing experience with reliable project delivery
End-to-end design, R&D, and manufacturing under one roof for speed and quality
ISO 9001 certified; designs aligned with ASME, API and CE
Customised designs engineered for your process needs and the applicable regulations
Applications
Built to help you specify.
Sizing tools, decision guides, and technical references. Use them before, during, and after your evaluation.
Frequently Asked Questions
When does biogas need a dehumidifier?
Biogas needs a dehumidifier whenever it feeds equipment that is damaged by condensed water, such as gas engines, turbines, compressors, membrane upgrading units and fuel gas pipelines. Raw biogas leaves the digester saturated with water vapour, and any drop in temperature along the pipework condenses that water. The condensate carries dissolved H₂S and forms an acidic liquid that corrodes valves, meters and compressor internals and blocks low points in the line. A CRA gas dehumidifier removes this moisture upstream, so downstream equipment receives dry gas at a controlled dew point.
How does a biogas dehumidifier work and how is the dew point controlled?
A biogas dehumidifier cools the gas below its dew point so that water vapour condenses and can be drained off. CRA's dehumidifiers use refrigeration-based cooling to bring the outlet dew point well below the inlet gas temperature, with the condensate separated in an integrated knock-out vessel and removed through an automatic drain. The refrigeration package, heat exchanger, separator and drain are assembled on one skid. Desiccant and membrane drying also exist in the market for deeper dew points, and CRA can advise on the right approach when an application needs more than refrigerated drying.
How is a biogas dehumidifier sized for a plant?
A biogas dehumidifier is sized from the gas flow, the inlet gas temperature and moisture content, the target outlet dew point and the ambient conditions at the site. The downstream use also matters, because a gas engine, a compressor inlet and a membrane upgrading unit each set their own limit on moisture carry-over. CRA selects the cooling duty, heat exchanger and separator against these figures and designs the unit to run with the rest of the gas treatment train, including H₂S scrubbing and compression, so the dew point is held at the point where it matters.
Why does raw biogas need drying before it is used?
Raw biogas needs drying because it leaves the digester saturated with water vapour and carries H₂S, siloxanes and other trace contaminants with it. When the gas cools in pipework the water condenses, and the condensate dissolves H₂S to form an acidic liquid that attacks carbon steel, instrument tubing and compressor valves. Liquid slugs also block lines and trip equipment. Drying the gas, together with H₂S removal and, where needed, siloxane removal, is what makes biogas suitable for power generation, boiler fuel and upgrading to biomethane. CRA supplies these treatment stages as an integrated train.
Why does dew point control matter before a compressor or membrane unit?
Dew point control matters because liquid carry-over is one of the most common causes of premature compressor valve wear and membrane fouling. Ambient cooling in the pipework rarely holds the dew point low enough to prevent it, and gas that is dry at the dehumidifier outlet can still condense if it is cooled further at the compressor inlet. CRA's refrigeration-based dehumidifiers lower the outlet dew point well below the inlet gas temperature and remove the condensate automatically, so the unit can be installed directly ahead of the compression or membrane stage.