In general, gas membranes are polymer sheets are used to recover, purify or just separate gases.
Polymers can beare cross-linked in different ways to allow mechanical stability for various molecular cuts and the material they are made from can be blended depending on the gas being treated.
In oil and gas, petrochemical and chemical application often it is often required to recover part of the gas coming from a mixture of components with consequent economic benefit or to reduce the presence of some components that may effect affecton healthy if released in the atmosphere.
The membrane limits the motion of gas molecules passing through it so that some gases move more slowly than others or are completely excluded.
When a gas passes through the membrane, it is separated into both permeate and etentate streams. The permeated gas is the portion of the gas that thepermeates through the surface of the membrane whereas the retentate is the residual portion that does not permeate the membrane.
Nowadays, gas separation processes play an essential role in numerous industrial applications.
Gas separation using membranes is a potential alternative to conventional gas separation processes (such as absorption, adsorption, and distillation). Gas separation is a pressure-driven procedure in which the difference in pressure between the gas inlet of and the gas outlet of the product is used to.
Here’s a step-by-step explanation on how a gas separation process works to bring about gas purification:
1) The gas enters the liquid ring compressor.
2) The gas is compressed at the required pressure to get the best separation performance.
3) After the compression, the gas and liquid mix reaches the scrubber/separator that divides them.
4) The liquid comes back to the compressor, while the gas enters the membrane separator unit.
5) At the membrane stage, the required components are recovered
Since energy costs are always increasing, membrane technology for gas separation is going to play an extremely important role in reducing the environmental impact and overall costs of industrial processes.When compared to other gas separation technologies, utilizing membrane gas separators can bring much more beneficial results.
Conventional technologies, including the cryogenic distillation of air, condensation that removes condensable organic vapors from gas mixtures, and amine absorption that removes acid gases from natural gas, require a gas-to-liquid phase change, which significantly increases the energy costs. A phase change is not required in the membrane gas separation process.Additionally, gas separation membrane units are smaller so they are a perfect fit for amine stripping plants and offshore gas-processing platforms. They have a relatively small footprint, and the lack of mechanical complexity in membrane systems is another aspect that can simplify the work for operators.
The Vapor Recovery Unit (VRU) combines absorption or condensation and membrane separation. The system is designed to remove undesired vapors which allows operators to comply with current emission regulations. Such a unit usually includes a liquid ring compressor, a gas/ liquid separator a membrane stage and a vacuum pump(if required) Membrane gas separators, involved at the membrane stage, are used for recovering the gas products.
The functionality of a VRU system is based on removing vapors collected inside sealed hydrocarbon tanks by gas compression and suction. The system aims to decrease emissions coming from the vapors of gasoline and other fuels, and at the same time, recover valuable hydrocarbons to be sold or reused as fuel onsite.
As the world leader in liquid ring technology, Garo strives to provide their customers with tailor-made products and solutions for the most challenging applications in the oil & gas, chemical and petrochemical industries.
Choosing the right Vapor Recovery Unit for your application can raise numerous questions and doubts. Our dedicated website explains even the most complicated aspects and can give you a full picture of vapor recovery systems, their benefits, and types of compressors that will meet your needs.
Since 1947, Garo has collaborated with companies around the world to custom design compressors that enable safe handling of toxic and corrosive gases. More than 70 years of engineering expertise allows us to support clients from concept/FEED studies through project execution to site services and more.