1.NGL Recovery Unit
In addition to methane, natural gas (especially condensate gas and associated gas) generally contains a certain amount of ethane, propane, butane, pentane and heavier hydrocarbons. In order to meet the quality index of commercial natural gas or the quality requirements for hydrocarbon dew point of pipeline gas, or to obtain valuable liquid fuels and chemical raw materials, it is necessary to separate and recover hydrocarbons in natural gas according to certain requirements.
Currently, ethane, propane, butane, pentane and heavier hydrocarbons in natural gas are recovered in liquid form except ethane which is sometimes recovered in gas form. The liquid hydrocarbon mixture recovered from natural gas is called natural gas liquid (NGL). In China, it is generally called light hydrocarbon, which is inaccurate. The composition of NGL varies according to the composition of natural gas, the purpose and techniques of NGL recovery. The process of recovering condensate from natural gas is called NGL recovery, which is commonly called light hydrocarbon recovery in China. The recovered NGL is either directly used as a commodity or further separated into ethane, liquefied petroleum gas (LPG, which can be propane, butane or a mixture of propane and butane) and natural gasoline (C5+) according to relevant product quality indicators. Therefore, NGL recovery generally includes natural gas separation process.
2.The Purpose of NGL Recovery
To make the commodity gas meet the quality index;
To meet the quality requirements of pipeline gas transmission;
To maximize the recovery, either directly as product or further separated into related products.
3.NGL Recovery Techniques
NGL recovery can be carried out in oil and gas fields, natural gas processing plants and natural gas re-injection plants. Basically, there are three recovery techniques: adsorption, absorption and condensation separation.
