Supersonic Gas Conditioning-Low Pressure Drop TWISTER for NGL Recovery

Abstract

TX 75083-3836, U.S.A., fax 01-972-952-9435. AbstractTwister™ is an innovative gas conditioning technology which has been under development for natural gas applications. Condensation and separation at supersonic velocity is the key to some unique benefits. An extremely short residence time prevents hydrate problems, eliminating chemicals and associated regeneration systems. The simplicity and reliability of a static device, with no rotating parts, operating without chemicals, ensures a simple, environmentally friendly facility, with a high availability, suitable for unmanned operation. Full scale testing has been completed at five gas plants in the Netherlands, Nigeria and Norway, with varying gas compositions and operating conditions. The first commercial offshore Twister application started-up in December 2003 on the Petronas/Sarawak Shell Berhad B11 facility offshore East Malaysia. The key challenges and experience gained during the B11 Twister design, and operating experience to date, have resulted in some significant new developments. This includes the low pressure drop version of the Twister Supersonic Separator which also achieves a significantly improved hydrocarbon and NGL recovery performance. This improved performance has been confirmed during testing and details will be presented to describe the development, testing and initial commercialisation.Twister also has potential to be further developed for other specific future separation applications, such as deep LPG extraction, CO2, H2S and mercury removal, and for sub-sea gas processing.

Trends in Supersonic Separator design development

“…Twister separator which is based on air drying device was originally developed by Stork Product Engineering BV in 1989 [18]. Twister BV company is a joint venture between the Beacon Group and Shell launched in the year 2000 for developing the first generation of supersonic separators, trademarked Twister [19].…”

Problems Associated with Sour Gas in the Oilfield Industry and Their Solutions

“…87 Though the limited amount of space at many well sites, can often lead to a desire to transport the sour gas in its raw state and perform all necessary acid gas removal in larger plants onshore. So instead of removing the acid gas components, it becomes prudent to prevent their undesirable effects, namely formation of clathrate hydrates and pipe corrosion.…”

“…Twister operates by causing a drop in temperature by converting pressure into kinetic energy, similar to the way in which a turbo-expander converts pressure into shaft power. 86 After the initial inlet a Laval nozzle is used to expand the gas to supersonic velocity, resulting in a mist of droplets of condensed gases, all components of the sour gas are condensed, the desired natural gas as well as CO 2 and H 2 S. The vortex creates a centrifuge that forces the droplets up to the edge of the column. The liquids are separated off by the cyclonic separator and the stripped gas exits the far end.…”

“…One of the leading implementations of this technology is the Twister Supersonic Separator. [86][87][88] Twister was first implemented in Petronas/Sarawak Shell Berhad B11 offshore facility in East Malaysia in 2004 after a series of full scale tests in the Netherlands, Nigeria and Norway. 86,87 The B11 offshore facility has been running continuously and successful since its start up, sweetening the sour gas and thus preventing corrosion.…”

“…[86][87][88] Twister was first implemented in Petronas/Sarawak Shell Berhad B11 offshore facility in East Malaysia in 2004 after a series of full scale tests in the Netherlands, Nigeria and Norway. 86,87 The B11 offshore facility has been running continuously and successful since its start up, sweetening the sour gas and thus preventing corrosion. Twister operates by causing a drop in temperature by converting pressure into kinetic energy, similar to the way in which a turbo-expander converts pressure into shaft power.…”