Natural Gas Dehydration Unit Options for Off-Grid …

Elsevier's 2024 reference volume on natural gas dehydration gives glycol absorbents a chapter of their own. No surprise there. TEG dehydration is the method most engineers learn first, and it's what most people picture when they hear natural gas dehydration unit.

The EPA's Natural Gas STAR program found something else worth knowing. Partners that traded glycol units for desiccant units saw methane, VOC, and HAP emissions fall by 99 percent. Their operating and maintenance costs went down too.

So why is a reboiler still burning fuel gas at a low-volume well two hours from the yard?

Our position is simple. On low-volume, off-grid wells, the right dehydrator has nothing to plug in, nothing to burn, and nothing to tune. That's a single-tower deliquescent dryer, with small adsorbent or regenerative units added only where a device truly needs minus 40°F gas.

Count What Your Natural Gas Dehydration Unit Needs to Keep Running

A glycol dehydration system is a small plant. Wet gas meets TEG in a contactor tower, a pump circulates the glycol, and a reboiler burns fuel gas to boil the water off. The still column then vents what the glycol absorbed, BTEX included.

Every one of those parts needs fuel, power, or adjustment. Any of them can quit between visits. On a pad you only see twice a week, a dead pump or a cold reboiler can cost days of production before anyone notices.

We carry single-tower deliquescent dehydrators like the Van Gas PLD, and they skip all of it. Free liquids drop into a large sump at the bottom of the vessel. The gas then rises through deliquescent tablets that dissolve as they pull out water vapor.

There's no pump, no reboiler, no electrical requirement, and no fuel gas burned. Vessels are built and stamped to ASME Section VIII, with standard ratings of 280, 720, and 1440 psig. Servicing this natural gas dehydration unit comes down to topping off tablets and draining brine, which fits into a normal pumper route.

Pay for Drying Based on the Gas You Actually Move

Desiccant consumption on the PLD tracks actual gas flow. Move less gas, and you use fewer tablets. A glycol reboiler has to hold regeneration temperature whenever glycol circulates, so its fuel draw doesn't fall in step with a declining well.

That gap widens every year a well spends on decline. A deliquescent natural gas dehydration unit gets cheaper to run as volumes taper, right when lease operating expense per Mcf starts to sting.

Disposal stays simple, too. The spent brine can go out with your other produced liquids, so there's no separate waste stream to haul. With no still vent, the dehydrator itself puts out no BTEX or VOC emissions.

Dry Fuel Gas and Instrument Gas Without Running a Wire

Remote leases run a lot of equipment on their own gas. Tank heaters, flare pilots, generator sets, compressor engines, and pump jacks all burn it. When that gas is wet, water condenses in the fuel lines, damages engines, burns poorly in heaters, and freezes when the weather turns.

Our fuel gas dryers handle that kind of gas conditioning with no power or utilities. The deliquescent models install right in the line feeding the equipment.

Instrument gas is the other headache. Pneumatic controllers, dump valves, and float controls on separator pads all run on produced gas, and they're usually the first things to freeze.

Plenty of crews fight that with methanol for hydrate inhibition, every winter, at every site. Drying the gas first keeps hydrates from forming at all. A small natural gas dehydration unit on the supply line to those controls removes the water and leaves the hydrocarbon content of the gas alone.

Our instrument gas dryers fit remote pads for that reason. They need no utilities and very little operator training, which matters at a site nobody visits daily.

Weigh the Dew Point Trade-Off Before Ruling Out Deliquescent

The strongest case against our position is dew point. Deliquescent tablets won't reach the minus 40°F that solid desiccant dehydration delivers, and molecular sieve dehydration goes far lower than either.

That's true, and it matters at a cryogenic plant. Molecular sieves belong upstream of natural gas processing equipment that chills gas hard enough to freeze trace water.

A remote wellsite needs something different. Good dew point control there means keeping the water dew point below the coldest temperature your lines will see. Meeting pipeline water specs and replacing TEG units are both standard PLD applications.

When one instrument does need minus 40°F, add an inline adsorbent dryer at that point. Our ID Series units get there with no power and no liquids to dispose of, at 0 to 250 psig. The desiccant saturates over time and gets replaced, so plan for that on your route.

Size the natural gas dehydration unit for the coldest morning on the lease, then polish only the points that demand more.

Know When a Powered Dryer Earns Its Place

A deliquescent dryer is the wrong pick in one clear case: you need continuous minus 40°F gas with no refills, and you already have power. For that site, a regenerative natural gas dehydration unit earns its extra hardware.

Our HLSXG regenerative dryers fit that job. Each one has two desiccant towers. One dries the gas while the other regenerates with depressurized purge gas, and a timer alternates them.

• Minus 40°F pressure dew point
• 55 to 800 SCFM at 100 PSIG
• 250 PSIG maximum working pressure
• 115V or 12V DC power
• Explosion-proof controls rated Class 1, Division 1, Groups C and D

Those strengths come with conditions. The dryer needs a power source you trust, which at a remote site usually means a 12V DC supply fed by solar panels. Solar panels on remote leases also have a way of walking off. The unit vents purge gas, so you need a flare or vapor recovery unit to send it to.

Pick the Right Natural Gas Dehydration Unit for Each Point on the Pad

Run each point on the pad through this list before you order anything.

• No power, low or declining flow, gas headed to sales: a single-tower deliquescent dryer like the PLD.
• Fuel gas feeding heaters, pilots, or engines: a small deliquescent fuel gas dryer ahead of the equipment.
• Pneumatic controls that freeze in winter: a deliquescent instrument gas dryer, plus an inline adsorbent unit where a device needs minus 40°F.
• Reliable power, a flare or VRU, and a need for continuous minus 40°F: an HLSXG regenerative dryer.

Then run one check. Pull last winter's freeze-off records and the coldest temperature logged on the lease. If your dew point target lands well above minus 40°F, a no-power natural gas dehydration unit will likely cover every point on that pad.