Natural Gas Filter Dryer for Instruments

 In Gas Filtration, Instrument Filter Dryers – High Pressure

IMAC natural gas filter dryers (driers) provide filtration for high-pressure instruments. The dryers protect the expensive equipment by removing contaminants before reaching the devices. IMAC offers different filter dryer switching assemblies to filter, dehydrate, and regulate gas. The filters are fully compatible with Welker filter dryers and also interchangeable with Becker dryers with a kit.

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Natural Gas Filter Dryer

IMAC Systems has manufactured filter dryers for over 20 years. They are made in the US and have been IMAC Systems’ fastest-growing product line over the last five years.

control valve with filter dryer (drier)

Pictured is a control valve with IMAC Filter Dryers.

The filter dryers provide maximum filtration and drying for supply gas to control instrumentation, catalytic heaters, and other applications which require clean, dry gas. Instrument Filter Dryers help reduce the Joule-Thomson effect and prevent costly freeze-ups in cold environments. They are available in different media (desiccants) for various applications to remove solids, moisture, aerosols, odorants, and H2S. The Instrument Filter Dryer is easy to install, has trouble-free maintenance, and provides maximum scrubbing. Eliminating contaminants from the gas reduces costly downtime and increases the performance and longevity of downstream equipment.

The Filtration Process

IMAC FD-5 filter dryer element illustration

IMAC FD-5 filter dryer element illustration

The IMAC Instrument Filter Dryer conditions high-pressure gas to ensure reliable service. The conditioning occurs in several steps. First, the gas stream redirects 180-degrees into the filtering element. This shift in direction “knocks out” free water. The liquid collects in a reservoir at the bottom of the filter dryer. The gas continues to a 50-micron sintered polyethylene disc, which removes particulates and some heavy ends. A tightly woven felt disk helps absorb free liquids and keeps the desiccant in place. After this, the gas stream passes thru the desiccant bed. Once thru, the gas bookends with another felt disk and 50-micron sintered polyethylene disc. Lastly, the gas passes through a polishing filter (3-micron filter paper) to remove dust and fine particulates.

The filter dryers are available in three main sizes (from smallest to largest): FD-19, FD-4, and FD-5.  They all function similarly, though they have different volumes for different needs. All three models are rated to 1500 PSI, allowing use in ANSI 600 systems. The standard ports on the filter dryers are ¼”, available in 3/8” or ½.”

Desiccant Dryer Options

infographic natural gas filtration and filters

Click on the image to view the infographic.

The filter dryer is available with various desiccants, including silica gel, molecular sieve, activated charcoal, and H2S removal desiccant to accommodate pressure cuts (regulators) and gas conditioning (catalytic heaters), automatic filter switching, or drain valves, to name a few.

  • Silica Gel (Standard) – The most common model uses silica gel to dry gas and create freeze protection when reducing the gas’s pressure for pneumatic controls. The filter dryer removes condensable contaminants and vaporized moisture and prevents hydrate formation.
  • Activated Carbon – The activated carbon desiccant adsorbs impurities and organic compounds, including removing mercaptan (a standard gas odorant). It also removes lubrication oil.
  • Sulfatreat / Sulfatrap – The Sulfatreat desiccant removes hydrogen sulfide and other organic compounds from gas.
  • Molecular Sieves, PTFE, and others –  Molecular sieve desiccants dehydrate solvents. Other options are available depending on the customer’s needs.

Typical Applications for Filter Dryers

Here are some typical applications for using the IMAC filter dryers:

  1. Pneumatic Controls – high-pressure gas cuts from main regulated to operate in valve actuation,  gate stations/regulation stations, measurement skids, pigging stations, dump, control panels
  2. Pilot regulator protection – commonly used with Mooney, Axial Flow Valves & Pietro Fiorentini to protect the pilot regulator
  3. Line heaters & catalytic heaters (conditioning the fuel gas)
  4. Thermoelectric generators (TEGs) (conditioning the fuel gas)
  5. Methanol injection systems
  6. Valve pilot controllers
  7. Odorizers


pressure reduction assembly with filter dryer IMAC 1367

IMAC 1367 pressure reduction assembly with a filter dryer

The Filter Dryers are available with many ancillary products, including moisture indicators (Tattle Tales),  knock-outs, catalytic heaters, instrument regulators, bypasses.

The filter dryers are also available as complete systems, including regulation systems and supply systems. IMAC manufactures gas pressure reduction assemblies (see IMAC 1367 on the right) and conditioning systems with filter dryers, pressure regulation, catalytic heating, pressure relief, or live bypasses.

Instrument Supply System

instrument gas supply system

IMAC Systems instrument gas supply system including the switching assemblies for filter dryers

IMAC offers switching assemblies that mount two filters in parallel with instrument pressure regulators. The objective, of course, is to increase the time between filter changes. By setting one of the regulators on a filter 20 PSI higher than the other, only one filter is used at a time. When the in-service filter becomes saturated, hydrates pass through, the filter freezes, and the second filter becomes operational. Valves on these assemblies facilitate easy filter changeouts without disrupting service.

Download the Instrument Supply System cut sheet.

Welker and Becker Precision Equipment Compatible

The IMAC filters are interchangeable with Welker Filter Dryers and Becker Filters when using the available kits from IMAC Systems.

Don’t forget to change your filter elements! If you would like more information, visit the IMAC instrument filter dryer, or download the brochure.

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Showing 2 comments
  • Jose B. Fuentes

    susan, one of our major problem on most PETRONAS platform is wet gas. at present we have one project wherein our core team provide JT valves… its on going installation but I doubt it wont work pr its i..back in 2013 a company is US offered AME auto mist eliminator but it wasnt pushed through for unknown reason…
    ANY INPUTS from your end will be much appreciated.

    Joe f

    • Adam

      Jose did your problem get resolved okay?

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