CNG Decompression | CNG Letdown | CNG PRS


While natural gas is normally transmitted in pipelines at pressures up to 1400 PSIG, Compressed Natural Gas (CNG) is normally stored in pressure vessels up to 3600 PSIG. For CNG to be usable, it must be decompressed or ‘let down’ to a more manageable pressure. This is a crucial part of the CNG PRS (Pressure Reduction System) process. Due to the Joules Thompson Effect, where gas temperature will drop when the pressure drops, this letdown of pressure means heat must be put back into the gas stream to prevent freezing of sensitive instruments and pipelines. Each of Bruest’s LD series CNG Let Down Systems begins with Bruest’s proven catalytic heaters. These heaters are rated for operation in Class I Division 1 or Division 2 locations. Furthermore, as catalytic heaters have virtually zero emissions, the LD series letdown stations are not only safe but environmentally friendly.

The LD series letdown stations offer a variety of starting power, packaging, and control options. Input starting power options range from 12VDC to 480VAC. The LD series is designed to be portable. The smallest system weighs less than 60 pounds. Larger systems can be skid mounted, containerized, or mounted on trailers for easy deployment to job sites. Controls can be manually operated, or full PLC controlled with remote interface capabilities. The optional patent pending control system allows simultaneous connection of multiple CNG trailers to minimize flow variations due to supply pressure issues. In addition to these predefined systems, Bruest’s engineering team is ready to offer customized packages to best meet individual application requirements.


With the abundance of natural gas, CNG is rapidly becoming the fuel of choice for remote locations that do not have access to normal gas pipelines or in situations when gas supply has been interrupted. CNG can be 3 to 4 times lower in cost per MMBTU than Synthetic Natural Gas (SNG), diesel, fuel oil, and LPG. In addition to the cost savings, Bruest’s LD series letdown stations offer environmental savings as well. The catalytic heaters have virtually zero of the controlled emissions gasses; NOx is less than 10PPM in most cases.