高压天然气乙烷回收高效流程

High efficiency process of ethane recovery for high-pressure natural gas

关键词:  高压天然气  凝液回收  吸收塔  乙烷回收工艺  低温冷凝法 

Key words:  high-pressure natural gas  condensate recovery  absorber  ethane recovery process  low-temperature condensation method

摘要:

在对高压凝析气田气回收乙烷及以上组分时,可利用的现有乙烷回收流程存在系统冷量过多、脱甲烷塔气液分离效果差和系统能耗高等问题。在部分干气循环工艺(RSV)的基础上,提出一种高压天然气的乙烷回收高效流程(HPARV)。该流程在RSV工艺的基础上增加了1台高压吸收塔,吸收塔与脱甲烷塔的操作压力相互独立,既保证了较高的乙烷回收率,又降低了外输干气的再压缩功率。HPARV工艺有效解决了传统RSV乙烷回收流程系统能耗高、对高压原料气适应性不强和脱甲烷塔气液分离效率差等问题。研究实例表明,当原料气压力大于7.0 MPa时,HPARV工艺对原料气气质组分变化及原料气压力变化均具有较好的适应性,乙烷回收率高达93%以上。与相同乙烷回收率下的RSV工艺相比,HPARV工艺能大幅度降低乙烷回收装置的综合能耗。 

Abstract:

The existing ethane recovery processes have many problems including high cooling capacity of the system, poor gas liquid separation effect and high system energy consumption when the ethane and above components are recovered in the high-pressure condensate gas field. In this paper, a high-pressure natural gas recovery (HPARV) process basing on recycle split-vapor (RSV) process was proposed. Basing on the RSV process, a high-pressure absorber was added to the process. The operating pressure was independent of the absorber and the demethanizer. Accordingly, the higher ethane recovery rate was guaranteed, and the compression power of the transmission dry gas was reduced. The HPARV process of ethane recovery could effectively solve the problems of high energy consumption, poor adaptability to high pressure feed gas and poor gas-liquid separation efficiency of the demethanizer of traditional RSV ethane recovery process system. The study results showed that HPARV ethane recovery process had strong adaptability to the change of feed gas composition and pressure, and the recovery rate of ethane was more than 93% when the gas pressure was greater than 7.0 MPa. The HPARV process could also greatly reduce the comprehensive energy consumption of ethane recovery unit compared with the RSV process which had the same ethane recovery rate.