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Draft for wiki: "Supersonic Gas Separator"
Definition:
The Supersonic Gas Separator is a device that combines condensation by temperature reduction with cyclonic gas/liquid separation into a tubular, static processing unit that removes one or several gaseous components out of a mixed gas using only a small part of the field pressure as energy and is doing this with great advantages when compared to commonly used technologies.
Background:
Raw natural gas out of a well is usually not a saleable product but a mix of various hydrocarbonic gases and condensates with other gases, liquids and solid contaminants. This raw gas needs gas conditioning to get it ready for pipeline transport and later processing in a gas processing plant to separate it into its components.
Some of the common processing steps are CO2 removal, dehydration, LPG extraction, dewpointing. Technologies used to achieve these steps are adsorption, absorption, membranes and low temperature systems achieved by refrigeration or expansion through a Joule Thomson Valve or a Turboexpander.
If such expansion is done through the Supersonic Gas Separator instead, energy is used more efficiently and great mechanical and operational advantages are gained as detailed below.
The Device:
A Supersonic Separator consists of several sections in tubular form similar to the sketch below:
The feed gas (consisting of at least two components) first enters a section with an arrangement of static blades or wings, which induce a fast swirl (In other/earlier constructive solutions this swirl was induced further downstream). Thereafter the gas stream flows through a Laval Nozzle where it accellerates to supersonic speeds and undergoes a deep pressure drop to about 30% of feed pressure. This is a near isentropic process and the corresponding temperature reduction leads to condensation of target components of the mixed feed gas which form a fine mist. In the next section - often called "working zone" -the droplets agglomerate to larger drops and the swirl of the gas leads to cyclonic separation. The dry gas continues forward while the liquid phase together with some slip gas (about 30 % of the total stream) is separated by a concentric divider and exits the device sideways. The final section is a diffuser (each for both streams) where the gas is slowed down and about 80% of the feed pressure is recovered. This section might also include another set of static devices to undo the swirling motion.
The Installation Scheme:
Separation of a mixed hydrocarbon is obviously not achieved by a piece of equipment on its own, but requires a certain process scheme which includes further auxiliary equipment. The typical scheme for supersonic separation is a simple arrangement, where the feed gas first flows through a heat exchanger where it is cooled by the gaseous stream of the separator unit. The gas then continues through the supersonic separator and flows through the mentioned heat exchanger to the pipeline or further processing. The liquid phase from the supersonic separator goes into a 2-phase or 3-phase separator, where the slip gas is separated from liquid hydrocarbons and - if applicable - from liquid water. The gaseous phase joins the exit of the supersonic separator, the hydrocarbons go for transport, storage or further processing and the water for treatment and disposal. Depending on the task at hand many other schemes are possible and might for certain cases have advantages. Variations include: No heat exchanger, a second heat exchanger to use the liquids as cooling medium, incorporation of a splitting column, splitting of streams etc.. Those schemes are very much part of the supersonic gas separation and several of them are protected by patents.[1]
Advantages and Application:
The Supersonic Gas Separator has a higher efficiency than a JT valve in all conditions of operation. It can also achieve extraction in many cases where the JT valve has no extraction at all (high temperature/high pressure). The supersonic gas separator has a 10 - 20 % higher efficiency than a Turboexpander in many cases. The Supersonic Separator has a smaller footprint and a lower weight than a Turboexpander and needs smaller capital investment. It is completely static and as such requires very little maintenance and no consumables (such as lubricants). The fact that no operational or maintenance personnel is required might enable unmanned platforms or facilities with the associated large savings in capital and operational expenditure.
The fields of application commercially developed on an industrial scale are
- dehydration
- dewpointing (water and/or hydrocarbons)
- LPG extraction
Applications in the laboratory stage are
Commercial Realization:
There are several patents on Supersonic Gas Separation, relating to features of the device as well as variations of installation schemes. The technology has been researched and proven in laboratory installations since xxx and has meanwhile moved successfully into industrial applications for dehydration as well as for LPG extraction. Consultancy, engineering and equipment for Supersonic Gas Separation are being offered by Twister BV under the brand "Twister" and by Melewar Gas Technologies Sdn Bhd under the brand "3S".
Bibliography:
Malyshkina, M.M. (2008), High Temperature, 46 (1) {{citation}}: Missing or empty |title= (help).
non nominare (23 may 2005), "Supersonic nozzle efficiently separates natural gas components", Oil % Gas Journal {{citation}}: Check date values in: |date= (help)CS1 maint: date and year (link).
Nastras, Thomas D. (2005), "The Business Development Story in Russia", Hart Energy's E & P Magazine (12).
non nominare (Aug 2002), World Oil magazine, 223 (8) {{citation}}: Missing or empty |title= (help)CS1 maint: date and year (link).
Outside Links:
- ^ Malyshkina