Glycol Dehydrator

Glycol Dehydrators, part of natural gas dehydration systems, remove water vapor from gas streams to prevent the formulation of hydrates and corrosion in pipelines.

Exterran’s Glycol Dehydration Unit is a reliable, efficient system for removing water from natural gas well streams in order to meet typical pipeline and process specifications. Multiple stages of removal are contained on a single skid-mounted unit, giving you a wide range of options and flexibility to configure the system to your specific application.

Key Benefits

Reliability

  • Lower top tray approach temperature to ensure lower loss of lean glycol
  • Gas is captured in the flash gas separator to fuel the reboiler, which reduces fuel costs and reduces air emissions
  • Replaceable filter elements protect from scale, sludge and sediment
  • Better filtration and large heat exchanger extend pump life

Efficiency

  • Lower BTU flux rate extends fire tube life
  • Ability to achieve a high throughput with a vane/wire mesh mist extractor combination

Flexibility

  • Compact tower with 10:1 turndown and 10 tray equivalent capacity
  • Hat tray can handle full glycol capacity in the tower during shutdown

How it Works

Wet gas enters the bottom of the absorber tower and ascends through a mist extractor where fine liquid particles are removed. As the gas rises through the tower’s packing or bubble cap trays, water is absorbed by descending lean glycol (water removed through regeneration process), which is continually pumped to the top of the tower. Drier gas exits the top of the tower and passes through the glycol/gas heat exchanger to the gas outlet. The rich glycol (wet with absorbed glycol) collects in the hat tray at the bottom of the tower and flows to the power side of the glycol pump. From the pump, the rich glycol flows through a reflux coil, heat exchanger and flash gas separator, which divides gas and entrained hydrocarbons from the glycol. The gas then flows to the fuel gas scrubber and the lean glycol flows through a filter into the reboiler. As the reboiler drives off water vapor through the still column, the hot, reconcentrated glycol flows from the reboiler to the sparger box to remove additional water vapor. The lean glycol flows to the storage compartment and then to the heat exchanger for cooling. The cooled, lean glycol then flows through a glycol sock filter before passing to the glycol pump. Lean glycol and gas from the absorber together power the glycol pump, which pumps the glycol through a glycol/gas heat exchanger to minimize glycol loss and then to the absorber tower to continue the dehydration process cycle.

Standard Features & Options

Regenerator

  • Energy-saving shell insulation with aluminum jacket
  • Removable fire tube and stack
  • Thermostat with thermowell
  • 50-550° F thermometer with thermowell
  • High reboiler temperature fuel gas shut-off with manual reset
  • Fuel gas regulator, scrubber and pressure gauges
  • Flame arrestor with burner and pilot assembly
  • Integral insulated storage compartment
  • Liquid level gauge assembly
  • Glycol sock filter with initial elements
  • High-pressure glycol strainer
  • External glycol/glycol heat exchanger
  • Pump bleeder valves
  • Energy exchange glycol pump (electric on 2 MMBTU/Hr unit and larger)
  • Heavy-duty welded structural steel skid with lifting lugs and pull bars
  • Packed still column with reflux coil (all units larger than 125 MBTU/Hr)
  • Complete piping for skid hookup, including absorber and reboiler isolating valves for units up to 500 MBTU/Hr
  • Bent tubing and socket weld glycol piping and valves for one inch and larger pipe sizes to help prevent leaking

Absorber

  • Glycol distributor
  • 1440 psig design pressure
  • Stainless steel mist extractor
  • External glycol/gas heat exchanger
  • 0-200° F dial thermometer with thermowell
  • Pressure gauge with isolating valve
  • Pneumatic liquid level controller
  • Thermal relief valve
  • Drain valve
  • Reflex gauge glass assembly with gauge cocks
  • Lifting lugs
  • Random Packed Absorber
    • 7:1 turndown
    • 8 tray capacity equivalence
    • Diameter sizes from 6 to 16 inches
  • Structured Packed Absorber
    • Hotter gas handling capability
    • 10:1 turndown
    • 10 tray capacity equivalence
    • Diameter sizes from 24 to 60 inches

Trayed Absorber

  • 8 bubble cap trays
  • 5:1 turndown
  • Diameter sizes from 16 to 72 inches

Options

Complete Glycol Dehydration Unit

  • Burner safety low (BSL)/ignitor
  • High reboiler temperature fuel gas shut-off with manual reset
  • Solar panels to power burner safety low detector
  • Programmable logic controller system (PLC)
  • Burner management system
  • LSL/LSH connections
  • Adherence to API 14C recommended practices

Regenerator

  • Stack arrestor and down-draft diverter
  • Environmental drip pan
  • Pilot flame-out safety shut-down with manual reset
  • Spare glycol pump and manifold for standby service
  • Alternate gas or electric standby pump on 500 MBTU/Hr and smaller units
  • Glycol pump shut-down
  • Glycol charcoal filter on 125 and 300 MBTU/Hr units (standard on larger units)
  • Glycol metering
  • Gas metering for sparger box
  • Special paints and coatings

Absorber

  • Additional packing or bubble cap trays
  • Skid mounting
  • Environmental drip pan

General

  • Sour gas service built according to the NACE standard