Ethane recovery method using combination of pre-pressurization and propane refrigeration

Abstract

The invention discloses an ethane recovery method using a combination of pre-pressurization and propane refrigeration, belonging to the technical field of natural gas processing. The method is established on the basis of a conventional ethane recovery process; directed at the characteristic that a low-pressure rich gas ethane recovery process has great demand for cooling capacity, the method adopts the combination of feed gas pre-pressurization and propane refrigeration; so the refrigerating capacity of an expansion machine can be increased under the working condition that the pre-cooling capacity of the feed gas is insufficient, and the ethane recovery process has a high ethane recovery rate (greater than 95%) under a low-pressure rich gas working condition. According to the method, a compressor is arranged at a process inlet to pressurize the feed gas, so latent heat of vaporization of the feed gas is effectively reduced in a high-pressure state, cooling quantity required by precooling of the feed gas is reduced, and the circulation quantity of propane is reduced; and thus, the energy consumption of a refrigeration cycle compressor and total energy consumption of the process arereduced under the condition that high ethane recovery rate is guaranteed. Meanwhile, compared with an ethane recovery process with the same ethane recovery rate and with a stepped refrigeration cycleor mixed refrigerant cycle, the whole process structure of the method in the invention is greatly simplified, and the design and operation of the method are easy.

Description

technical field [0001] The invention relates to the technical field of natural gas processing technology, in particular to the ethane recovery method of low-pressure rich gas combined with pre-pressurization and propane refrigeration. Background technique [0002] As the price of crude oil continues to rise, major domestic oil and gas fields have gradually realized that condensate recovery of natural gas can produce huge economic benefits. At present, the most commonly used ethane recovery process is the partial dry gas recirculation process, which has the characteristics of high recovery rate, low energy consumption, and strong adaptability to the quality of raw gas. However, when the pressure of raw gas is low and the gas is rich, The partial dry gas recirculation process requires the addition of an auxiliary refrigeration system to maintain its high efficiency. At present, few literatures and patents have studied the condensation and reflux process of the deethanizer ove...

AI Technical Summary

Problems solved by technology

When the raw material gas pressure is insufficient and the gas is rich, the propane pre-cooling temperature cannot meet the actual demand, and the process ethane recovery rate will drop significantly. At the same time, considering the cooling of the top gas of the deethanizer, the matching effect of the two cooling temperature levels is poor , if only the propane refrigeration system is used, the energy consumption of the propane refrigeration cycle compressor will increase significantly

[0004] In order to overcome the problems of high energy consumption and low ethane recovery rate in the ethane recovery process using a single propane refrigeration system, the present invention proposes an ethane recovery method for low-pressure rich gas combined with pre-pressurization and propane refrigeration, aiming at ensuring Effectively reduce process energy consumption under the condition of high ethane recovery rate

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