Study on treatment process of high-salinity cyclamine waste liquid in a natural gas purification plant

Author of the article:XIAO Fang1, LIAO Xiaowei1, FAN Rui2, LIAO Tie3, LI Yunlong 1, CAO Liang1

Author's Workplace：1. CPECC Southwest Company, Chengdu, Sichuan, 610041, China; 2. PetroChina Southwest Oil & Gas Field Company, Chengdu, Sichuan, 610215, China; 3. PetroChina Southwest Oil & Gas Field Company Natural Gas Purification Plant Wanzhou Branch, Chongqing, 404002, China

Key Words：Amine purification; Na2SO4; Waste liquid; High-salinity cyclamine; Meeting the requirements of the discharge standard

Abstract：In natural gas purification plants, the wastewater produced by resin regeneration in the amine purification unit (APU) of the tail gas oxidation process contains a large amount of organic amines and sulfates, and has poor biodegradability. This paper took the tail gas oxidation process wastewater as the subject of the study to carry out research on the integrated process, and formed a complete set of tail gas waste water treatment process of“pretreatment→reverse osmosis desalination→electrodialysis membrane concentration and separation→combined oxidative degradation→evaporative crystallization”. After the above treatment process, followed by the biochemical treatment, the COD of the produced water was reduced to 81.5 mg/L, the ammonia nitrogen concentration was less than 1 mg/L, and the sodium sulfate concentration was reduced to 0.23 g/L, meeting the requirements of the discharge standard. The research results can provide technical guidance for future engineering design.