A method for recovering light hydrocarbons from natural gas and oilfield associated gas

Abstract

The invention discloses a method for recovering light hydrocarbons from a natural gas and an oilfield associated gas. By adopting a pressure swing adsorption process, the adsorbed light hydrocarbons are recycled by desorption, silica gel and a dedicated 13X adsorbent are compounded and filled, and the yield of methane and the recovery rate of the light hydrocarbons, especially ethane, are improved by utilizing the complementary advantages of the silica gel and the dedicated 13X adsorbent. When the content of ethane and light hydrocarbons of which the weight is greater than that of the ethane in the natural gas or the oilfield associated gas is more than 10%, the total concentration of recovered hydrocarbons is up to 80% to 90%, and the yield of CH4 is more than or equal to 95%; the adsorption quantity of C2<+> is up to 52.77ml / g above, and the adsorption quantity of C2 <+> / CH4 is more than 5.7.

Description

technical field [0001] The invention belongs to the field of gas separation, in particular to a method for separating light hydrocarbons from natural gas and oil field gas. Background technique [0002] At present, the separation and recovery methods of ethane and light hydrocarbons above ethane in natural gas mainly include oil absorption method, low temperature separation method and pressure swing adsorption method; oil absorption method utilizes the different solubility of different hydrocarbons in the absorption oil to convert natural gas The light hydrocarbon components in the oil are absorbed and separated. The absorbed oil is generally naphtha, kerosene, diesel or stable condensate oil. The greater the evaporation loss; the low-temperature separation method is to cool the raw material gas to below -135°C, and then separate light hydrocarbons such as ethane through condensation and rectification separation. This method has a high recovery rate of light hydrocarbons, bu...

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Problems solved by technology

[0002] At present, the separation and recovery methods of ethane and light hydrocarbons above ethane in natural gas mainly include oil absorption method, low temperature separation method and pressure swing adsorption method; oil absorption method utilizes the different solubility of different hydrocarbons in the absorption oil to convert natural gas The light hydrocarbon components in the oil are absorbed and separated. The absorbed oil is generally naphtha, kerosene, diesel or stable condensate oil. The greater the evaporation loss; the low-temperature separation method is to cool the raw material gas to below -135°C, and then separate light hydrocarbons such as ethane through condensation and rectification separation. This method has a high recovery rate of light hydrocarbons, but because it is operated at low temperature, the material High requirements, high equipment investment, relatively high energy consumption, inconvenient to start and stop; pressure swing adsorption method, using a specific adsorbent for CH 4 The difference in the adsorption capacity of other alkanes, reaching the difference between light hydrocarbons and CH 4 purpose of separation

[0003] The pressure swing adsorption method has a simple process, fully automatic operation, can adapt to different gas source pressures, low operating costs, and is convenient to start and stop. Therefore, the pressure swing adsorption method should be a better method among the methods for recovering light hydrocarbons in natural gas or oilfield gas. ; At present, this method is mainly used to remove heavy hydrocarbons in natural gas, and the application of light hydrocarbons in natural gas is less. It is all for the purpose of removing ethane in natural gas and light hydrocarbons above ethane to refine natural gas. Natural gas or The content of ethane and other light hydrocarbons in oilfield gas, ethane is the most, and there is no method for removing and recovering ethane in natural gas at present

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