FUEL GAS CONDITIONING (FGC)
Problem
The MTR membranes remove C3+ hydrocarbons and acid gases from fuel gas, significantly improving fuel quality. In many cases, raw natural gas is the only fuel available to operate compressor stations in remote locations or gas turbines on off-shore platforms. This gas often contains heavy hydrocarbons, acid gases, and water vapor, which can cause significant operating problems. These include pre-detonation, which can damage the internals of the firing chamber, and condensation of liquid hydrocarbons in the fuel line when temperatures drop. Injection of these liquids into gas engines or turbines can result in internal damage, incomplete fuel combustion, and carbon deposit build-up. Unscheduled downtime due to these problems leads to significant production losses.
Membrane Solution
VaporSep® membranes remove C3+ hydrocarbons and acid gases from fuel gas, significantly improving fuel quality. The membranes selectively permeate heavy hydrocarbons compared to methane. The permeated hydrocarbons are recovered as a liquid upon recompression and cooling, or are blended with the compressed natural gas. Capital and operating costs for the fuel gas conditioning (FGC) unit are low and payback times are short. Maintenance costs for the gas engine and turbine are reduced, and unscheduled downtime is minimized. The membrane system is simple to operate, reliable, and compact. Units are custom-designed to meet specific needs, and are skid-mounted for easy installation.
VaporSep fuel gas conditioning unit for gas turbines
Benefits
- Removes heavy components such as C3+ to clean up fuel gas
- Removes significant portions of acid gases such as H2S and CO2 that will reduce acid formation in the turbine or engine exhaust and reduce emissions
- Increases reliability of gas engines and turbines
- Operates at ambient conditions with no external heating required to prevent hydrate formation
- Eliminates need to de-rate gas engine
- Decreases maintenance costs and reduces unscheduled downtime
- Increases recovery of liquids
- Contains no moving parts, simple to operate and maintain
System Performance
This simple conditioning unit enables the pipeline compressor's gas engine to run on pipeline gas.
Gas Engine Unit
- Feed flow rate: 0.5 to 2 MMscfd
- Raw feed Btu value: 1350 to 1500 Btu/scf
- Conditioned fuel gas Btu value:1150 to 1250 Btu/scf
- Feed dew point: 80°F to 120°F
- Conditioned gas dew point: 40°F to 60°F
- C3+ removal: greater than 70%
- Unit dimensions and weight:
8 ft (L) x 6 ft (W) x 6 ft (H), 2,000 lb
Gas Turbine Unit
- Feed flow rate: 5 to 15 MMscfd
- Raw feed C3+ content: 8 to 20 vol%
- Raw feed dew point: 80°F to 120°F
- Conditioned gas dew point: 40°F to 60°F
- C3+ removal: greater than 70%
- Unit dimensions and weight: 20 ft (L) x 10 ft (W) x 10 ft (H), 8,000 lb