P C McKenzie Company

Industrial Boiler and Natural Gas Compressor Sales

  • About
  • Blog
  • Contact Us

CALL US TODAY - 877-244-4883

  • Compressors
    • IR Compressor Packages
      • IR 05H25NGSX
      • IR 05H25NGDX
      • IR 20H40NGSX
      • IR 20H40NGDX
    • IR Compressor Parts
    • IR Bare Blocks
    • Small CNG Station for Fleet Vehicle Refueling
    • CNG Rental Units
      • Sauer Natural Gas Compressor
    • Natural Gas Compressor Valve Rebuild Program
    • CNG Relief Valve Recertification
    • Troubleshooting Guide
  • BOILERS
    • Boiler Service and Boiler Repair
    • Patterson Kelley Condensing Boilers
    • Patterson Kelley Non Condensing Boilers
    • Unilux Water Tube Boilers
    • Cast Iron Boilers
    • Boiler Burner Parts
      • Industrial Combustion Lo-Nox Burners
      • Gordon Piatt Burner Parts
      • Weishaupt Burner Parts
    • Hurst Boilers and Hurst Boiler Parts
    • Atlas Boiler
    • Ajax Boiler Gaskets and Ajax Boiler Parts
    • Venting Solutions
      • Engine Generator Turbine Exhaust
      • Zero Chase Grease Duct
      • Boiler Domestic Water Heater Venting
    • Draft Induction Fan
  • AXELSON
    • Axelson Relief Valves
      • Axelson Relief Valve Maintenance
      • How Does an Axelson Safety Valve Work?
      • Garrett Safety Relief Valves
      • Axelson Orifice
      • How to Test Relief Valves – Axelson Test Stand for Pilot Valves
    • Axelson Spare Parts
    • Axelson ESP Pilot Sensor
    • Axelson ESPHL – High/Low Pressure Controller
    • Axelson Sand Probe Valve with Sensor
    • Axelson CRBBM Relay
    • Axelson Actuator Pneumatic Diaphragm Actuator
    • Axelson PRV Relay
    • Axelson Differential Pressure Sensing Unit
  • OIL CONTROL
    • Oil Level Regulator
    • Murphy Oil Level Controller LM500
    • Oil Supply Tanks
    • Slow Flow Meter REN
    • Continuous Oil Change Module by Ren
    • Liquid Level Switch by Ren
  • Boiler Parts
    • Boiler Pumps
    • A & F Chemical Feed Pumps
    • A & F Chemical Feed Tanks
    • Everlasting Blowdown Valve
    • Kewanee
      • Kewanee Boiler Parts
      • Kewanee Vortex Damper Rebuild
      • Kewanee Boiler Gaskets
      • Kewanee Burner
      • Cam Assembly
      • Kewanee Burner Blower Wheel
    • Pressure Reducing Regulators
    • Boiler Gaskets
    • Flame Controls
    • Weishaupt
    • Gauge and Site Glass
  • AMOT
    • Amot Thermostatic Control Valves
    • 3-Way Control Valves
    • Diaphragm Operated Gas Valve
    • Air Intake Shut Off Valve
    • Bearing Temperature Detector
    • High Temperature Valve
    • Overspeed Sensing Valve
    • Master Safety Control
    • Metal Particle Detector
    • Amot Temperature Sensor
    • Amot Electric Trip Lever Switch
    • Amot G Valve – 3 Way Temperature Control Valve
  • RESOURCES
    • CNG Safety – Is Compressed Natural Gas Safe?
    • CNG
    • CNG Storage Cascades
    • NGV Fast Fill Station
    • NGV School Bus Refueling
    • NGV Service Tips
    • NG Compressor Troubleshooting
    • Boiler Service Tips
      • Boiler Questions About Your Boiler
      • Boiler Glossary
      • Boiler FAQ
  • Solar Power

NG Dehydration

Dehydration of Natural Gas

Natural Gas usually contains significant quantities of water vapor. Changes in temperature and pressure condense this vapor altering the physical state from gas to liquid to solid. This water must be removed in order to protect the system from corrosion and hydrate formation.

In 1810, an English scientist by the name of John Dalton stated that the total pressure of a gaseous mixture is equal to the sum of the partial pressures of the components. This sdehydration of natural gastatement, now known as Dalton’s Law of Partial Pressures, allows us to compute the maximum volume of water vapor that natural gas can hold for a given temperature and pressure.

The wet inlet gas temperature and supply pressures are the most important factors in the accurate design of a gas dehydration system. Without this basic information the sizing of an adequate dehydrator is impossible.

As an example, one MMSCF (million standard cubic feet) of natural gas saturated @ 80 degree F. and 600 PSIG (pound per square inch gauge) will hold 49 pounds of water. At the same pressure (600 PSIG) one MMSCF @ 120 degree F will hold 155 pounds of water.

Common allowable water content of transmission gas ranges from 4 to 7 pounds per MMSCF. Based upon the above examples, we would have two very different dehydration problems as a result of temperature alone.

There are many other important pieces of design information required to accurately size a dehydration system. These include pressures, flow rates and volumes.

All gasses have the capacity to hold water in a vapor state. This water vapor must be removed from the gas stream in order to prevent the formation of solid ice-like crystals called hydrates. Hydrates can block pipelines, valves and other process equipment. The dehydration of natural gas must begin at the source of the gas in order to protect the transmission system.

The source of the gas moved through the transmission lines may be producing wells or developed storage pools. Pipeline drips installed near well heads and at strategic locations along gathering and trunk lines will eliminate most of the free water lifted from the wells in the gas stream. Multi stage separators can also be deployed to insure the reduction of free water that may be present.

Water vapor moved through the system must be reduced to acceptable industry levels. Typically, the allowable water content in gas transmission lines ranges from 4 lb. to 7 lb. per MMSCF. There are basically three methods employed to reduce this water content. These are:

1. Joule-Thomson Expansion
2. Solid Desiccant Dehydration
3. Liquid Desiccant Dehydration

Joule-Thomson Expansion utilizes temperature drop to remove condensed water to yield dehydrated natural gas. The principal is the same as the removal of humidity from outside air as a result of air conditioning in your house. In some cases glycol may be injected into the gas stream ahead of the heat exchanger to achieve lower temperatures before expansion into a low temperature separator.

Solid desiccant dehydration, also known as solid bed, employs the principal of adsorption to remove water vapor. Adsorbents used include silica gel (most commonly used), molecular sieve (common in NGV dryers), activated alumina and activated carbon. The wet gas enters into an inlet separator to insure removal of contaminants and free water. The gas stream is then directed into an adsorption tower where the water is adsorbed by the desiccant. When the adsorption tower approaches maximum loading, the gas stream is automatically switched to another tower allowing the first tower to be regenerated.

Heating a portion of the mainstream gas flow and passing it through the desiccant bed regenerates the Dehydration of natural gasloaded adsorbent bed. The regeneration gas is typically heated in an indirect heater. This undersaturated regeneration gas is passed through the bed removing water and liquid hydrocarbons.

The regeneration gas exits the top of the tower and is cooled most commonly with an air-cooled heat exchanger. Condensed water and hydrocarbons are separated and the gas is recycled back into the wet gas inlet for processing. The third method of dehydration is via liquid desiccant and is most common in the Northeast United States. This method removes water from the gas stream by counter current contact in a tray type contactor tower with tri-ethylene glycol (TEG). Natural gas enters the unit at the bottom of the adsorber tower and rises through the tower were it intimately contacted with the TEG solution flowing downward across bubble trays. Through this contact, the gas gives up its water vapor to the TEG.

The water laden TEG is circulated in a closed system, where the water is boiled from the TEG. The regenerated TEG then is recirculated to the contacting tower.

 

 

 

Natural Gas for Our Future
Natural Gas an ideal fuel source for many reasons, including safety. Natural Gas is lighter than air. This means that it will not puddle (like gasoline) or sink to the ground like propane, which is heavier than air. Instead, Natural Gas will rise and dissipate in the atmosphere. Natural gas also has a higher ignition temperature. This means that it is much harder to ignite. Also the storage systems used for compressed natural gas are infinitely stronger that the gasoline tanks found on cars and trucks today.
Learn more >>

CONTACT US

Toll Free: 1-877-244-4883
Fax: 412-257-8890
Phone: 412-257-8866

SHIPPING ADDRESS
P.C. McKenzie Company
1365 McLaughlin Run Road
Pittsburgh, PA 15241

MAILING ADDRESS
P.C. McKenzie Company
P.O. Box 112638
Pittsburgh, PA 15241

- P.C. McKenzie Company is located South of Pittsburgh, Pennsylvania -

P. C. McKenzie Company

© Copyright 2025 PC McKenzie · All Rights Reserved ·