Helidyne’s planetary rotor expander has been specifically designed for offshore oil platform and waste pressure recovery applications such as those encountered at gas pipeline regulator stations, city gates, and J-T gas processing plants.
Offshore Oil Platforms
As an alternative to diesel gen-sets, gas micro turbines, and sub-sea cables, Helidyne’s expander can utilize existing production pipeline infrastructure, used for reservoir stimulation, to generate emission-free offshore platform power. Gas pressure can be sourced from onshore compressor stations as shown in the diagram below, or directly from offshore pressurized gas wells.
The following diagram shows Helidyne’s expander installed as a bypass to a pressure reduction valve (PRV) at an existing regulator station. When the isolation valves are closed, gas continues to flow across the PRV as originally designed. This configuration insures uninterrupted service to downstream customers when the expander goes offline for maintenance. Power can be generated from as little as 100 psi pressure drop to as much as 1,200 psi.
J-T (Joule Thomson) gas processing applications can be arranged similar to regulator stations. The diagram below shows the expander bypassing the J-T valve, offering the same uninterrupted service benefits and easy integration into existing J-T skid packages.
The main advantage of using an expander in this application is achieving gas temperatures colder than those attained by the J-T effect alone. On average, an additional 15 to 20 F decrease in temperature can be expected, yielding significant gains in NGL recovery and revenue.
Helidyne’s planetary expander can operate on very “wet” gas. This is essential for wells producing rich gas which limits the J-T cooling effect to the point that further refrigeration is necessary to meet pipeline specification. In addition, its self-cleaning design and 1,440 psi rating make it uniquely qualified to do the job where others have failed. Self-cleaning is essential to remove hydrates and any mineral scale buildup that can form on rotor surfaces, causing other expanders to fail.
As an added benefit, shaft power from the expander can be used to drive a compressor or generator to provide power at “stranded wells” or sold directly to the grid if available.