Light hydrocarbon recovery refers to the process of recovering heavier components of natural gas compared to methane or ethane in liquid form. The mixture of propane and butane becomes liquefied petroleum gas (LPG), and the components above pentane and pentane become light oil. The light hydrocarbon recovery process is essentially a multi-component gas-liquid two-phase equilibrium system.The purpose is to control the hydrocarbon dew point of natural gas to meet the requirements of natural gas transportation. The recovered liquid hydrocarbon products can be used as high-quality fuels or chemical raw materials, with considerable economic benefits.
The process methods for light hydrocarbon recovery unit at home and abroad include adsorption, oil absorption, and condensation separation. At present, condensation separation method or various auxiliary cooling methods mainly based on condensation are commonly used. Natural gas is condensed to recover liquid hydrocarbons, and the process mainly consists of raw gas pretreatment, compression, dehydration, refrigeration, and condensate recovery. Dehydration refrigeration and condensate recovery are key processes in the light hydrocarbon recovery process. The effectiveness of these processes plays a crucial role in improving the yield of light hydrocarbons, effectively utilizing energy, and reducing energy consumption.
Oil absorption method is a method of separating different hydrocarbons by utilizing the different solubility of various components in natural gas in absorbed oil (such as naphtha, kerosene, or diesel).This method was widely used in the 1950s to 1960s, and there are still devices in operation today, especially for the separation of petroleum cracking gas in the petroleum refining industry.The absorption oil generally uses naphtha, kerosene, or diesel. The smaller the relative molecular weight of the absorbed oil, the higher the yield of light hydrocarbons, but the greater the evaporation loss of the absorbed oil. Therefore, when a high yield of hexane is required, absorption oil with relatively small molecular weight should generally be used.
According to different absorption temperatures, the oil absorption method can be divided into room temperature absorption, medium temperature absorption, and low temperature absorption.
The absorption temperature at room temperature is generally around 30 ℃, with the main focus on recovering C3+light hydrocarbons; The temperature for medium temperature absorption is above -20 ℃, and the yield of C3 is about 40%; The temperature for low-temperature absorption is around -40 ℃, and the yield of C3 is generally 80% -90%. At the same time, 35% -50% of C2 can be recovered.
Post time: Apr-10-2023
