Zero-sewage discharge novel process for development of natural gas fields

Abstract

The invention discloses a zero-sewage discharge novel process for development of natural gas fields. The zero-sewage discharge novel process comprises the following steps of: classifying sewage in a gas field into normal production sewage, domestic sewage, overhauling sewage, accident waste liquid, rainwater, production wastewater and gas field water, and collecting separately; next, guiding the normal production sewage, domestic sewage, overhauling sewage, accident waste liquid and initial rainwater to a biochemical treatment unit, guiding the production wastewater to an electrodialysis treatment unit and guiding the gas field water to a gas field water pretreatment unit; guiding all of up-to-standard sewage which is treated by the biochemical treatment unit previously and not completely recycled, concentrate generated after the treatment of the electrodialysis treatment unit and the gas field water treated by the gas field water pretreatment unit to an evaporative crystallization unit for advanced treatment; and after the quality of the water is up to the standard, recycling the water as make-up water for circulating cooling water or water for other production in the gas field, and separating out pollutants from the sewage in the form of crystalline salts, backfilling or recycling the crystalline salts, and finally, realizing zero discharge of the sewage.

Description

technical field [0001] The invention relates to the field of sewage treatment in the environmental protection technology, in particular to a novel process for zero discharge of sewage in the development of natural gas fields. Background technique [0002] The development of natural gas fields will produce a large amount of gas field water, production sewage, production wastewater and maintenance sewage. Gas field water is the formation water brought out from the gas well along with the natural gas during the gas production process and the condensed water produced by the separator due to the pressure change of the feed gas during the gas gathering and production process. Normal production wastewater refers to the production wastewater generated by the purification device during the natural gas purification process. The COD concentration is about 500mg / L. The main pollutants include methyldiethanolamine, sulfolane and triethylene glycol. Production wastewater refers to the se...

AI Technical Summary

Problems solved by technology

However, none of these can achieve zero discharge of sewage from natural gas field development, and the concentrated water and part of the sewage that meets the standard for desalination treatment need to be discharged into the water body or injected into the formation