What are the similarities and differences between the absorption stabilization system and the light hydrocarbon recovery system?

Light hydrocarbon recovery involves using multi-stage (usually 3 stages) compression-cooling and heat exchange in cold boxes to increase the pressure and lower the temperature of gases containing light hydrocarbons (such as natural gas, associated gas, and refinery gas) to below -50°C. By using expanders to reduce the pressure further, the temperature drops even more, causing the C2+ hydrocarbon components in the gas to condense into a liquid. This liquid is then separated from the gas phase through gas-liquid separation and product distillation, thereby yielding the desired products. Common products include liquefied gas, light oil, and solvent oil. There are also those that are further separated into individual hydrocarbons. There is also cryogenic light hydrocarbon recovery, which can reach temperatures as low as below -100°C, and is mainly used for recovering C2 hydrocarbons. An absorption stabilization system refers to a process that involves treating the crude gasoline and rich gas coming from the overhead oil-gas separator of the fractionator, in order to separate intermediate products such as dry gas, liquefied gas, and stabilized gasoline; these dry gas, liquefied gas, and stabilized gasoline are then sent to the double distillation unit for further purification.

In the case of light hydrocarbon recovery in a vacuum distillation system, the only difference lies in pressure, which is usually around 3 kg/cm3, and no compressors are required.