Compressor packages can be specifically designed to capture natural gas emissions with high levels of hydrogen sulfide from oilfield stock tanks. This type compression system is called a Vapor Recovery Unit (VRU).
Oil Flooded Screw Compressors
The oil flooded screw compressor is the most versatile technical solution for either dry or wet gas compression applications. The oil flooded screw compressor gives the operator the flexibility to adapt to rising discharge pressure requirements whenever they are encountered. Rotary screw compressors are very cost effective in handling high volumes of gas in field gathering and vapor recovery services.
With a general range of volumes from approximately 15 mscfd to 2 mmscfd and differential pressures up to 350 psig for single stage models, the oil flooded screw compressor has proven itself time and again to be an excellent choice for virtually any low to medium pressure application.
The rotary screw compressor design employs two helical rotors that intermesh. Oil is injected into the low pressure end of the rotors. Gas also enters the compressor at the low pressure end. The oil and gas mix travels down the length of the rotors where it is compressed. In this particular compressor design the oil is both the cooling medium and the compression medium.
Typical applications include vapor recovery, wellhead compression, medium pressure gas boosting, landfill gas recovery and casing head pressure reduction.
Quincy Line of Reciprocating Compressors
The Quincy line of reciprocating compressors offer the most cost-effective solutions for dry gas applications moving up to 550 mscfd at pressure up to 500 psi. The automatic bypass allows precise, consistent back pressure to be maintained on the well and reduces downtime and maintenance. The automated liquid transfer system dramatically reduces pumper workload and automated restart minimizes pumper callout.
Rotary Vane Compressors
Rotary vane compressors have been utilized for over 50 years in low-pressure compression applications. The relatively simple design of rotary vane compressors offer comparatively low initial cost and ongoing maintenance when compared to other compressors utilized in low pressure gas management.
Rotary vane compressors are excellent in relatively high volume/relatively low pressure differential applications. Volumes from approximately 20 mscfd to 2.5 mscfd are obtainable at differential discharge pressures up to 60 psig for single stage models.
These positive displacement machines utilize a slotted, eccentrically mounted rotor. Blades, or vanes, ride in and out of the slots and slide out due to centrifugal force. The vane contacts the inside of the cylinder wall. As the rotor turns, the gas is swept into an ever decreasing space, thereby affecting compression. This simple design allows for years of trouble-free service and makes rotary vane compressors a very attractive option for low pressure services.
Typical applications include vapor recovery, wellhead compression, medium pressure gas boosting, landfill gas recovery, and casing head pressure reduction.