Recently, CN Radio published a special article on the Shenhua Baotou project, "High-salt water salt crystallization device: Two years of reducing high-salt wastewater by about 4.896 million tons."

The Baotou Chemical Wastewater Desalination and Discharge Standard Emission Transformation Project was constructed by Shenhua Baotou Coal Chemical Co., Ltd., located in the southwest of Halinger Town, Baotou City, Inner Mongolia Autonomous Region, in the southern area of Baotou's planned Jiuyuan Industrial Park, and north of the existing Shenhua Baotou Coal Chemical plant.

The water received by the fractional crystallization system of this project has two sources: one is the concentrated brine produced after salt separation by the upstream nanofiltration device, which is mainly composed of divalent sulfates, with a high COD concentration; the other is the dilute brine from nanofiltration, which is mainly composed of monovalent chloride ions after concentration by reverse osmosis membrane. After treatment by this system, all the condensed water is reused, and the salt in the concentrated brine is separated into high-quality sodium chloride and sodium sulfate crystalline salts, and the COD and other miscellaneous salts that cannot be recovered are produced into miscellaneous salts, realizing "zero discharge" of industrial wastewater.

Hezhongsi (Beijing) Environmental Engineering Co., Ltd. (hereinafter referred to as Hezhongsi) is responsible for the process package design, key evaporation crystallization equipment supply, and technical services of the fractional crystallization system.

In order to treat the high-salt wastewater produced by the membrane method of the Baotou Chemical Wastewater Desalination and Discharge Standard Emission Transformation Project and achieve zero wastewater discharge and resource utilization, the Hezhongsi technical team, based on the influent water quality, divided the fractional crystallization system technology of this project into sodium chloride evaporation crystallization unit, sodium sulfate crystallization unit, mixed salt evaporation crystallization unit, and miscellaneous salt mother liquor rotary drying unit. Finally, the project achieved "zero discharge" and resource utilization of all wastewater.

Hezhongsi won the title of "Excellent Supplier" for the National Energy Group Shenhua Baotou Wastewater Desalination and Discharge Standard Emission Transformation Project with its excellent technology and professional engineering services.

The following is the original content from CN Radio:

Entering the various production workshops of the high-salt water salt crystallization device in the public works center of GuoNeng Baotou Coal Chemical Co., Ltd. Various equipment is arranged orderly in the workshops, and the running pumps emit rhythmic sounds. At this moment, all the high-salt wastewater in the plant is undergoing a magnificent transformation of recovery, utilization, and turning waste into treasure.

The high-salt water salt crystallization device is a technical transformation investment project optimized and upgraded by GuoNeng Baotou Coal Chemical Co., Ltd. based on the existing factory's environmental protection devices. It adopts the "pretreatment-membrane concentration-nanofiltration salt separation-freezing denitrification-evaporation salt making" process to achieve the complete reuse of water after desalination treatment of high-salt wastewater, and the maximum resource recovery and recycling of inorganic salts. Its design scale is to treat 4 million tons of discharged wastewater per year, and after completion, it can recover 3.3 million tons of product water per year, produce 15,300 tons of industrial sodium chloride per year, and produce 17,000 tons of industrial sodium sulfate per year.

This project is a project supervised by the Ministry of Ecology and Environment, the Inner Mongolia Autonomous Region, and the Baotou Municipal Government, and a safety and environmental protection hazard governance project of the National Energy Group. It was approved and established on July 29, 2019, and the investment decision was approved on April 20, 2020.

As of September 20, 2023, the high-salt water salt crystallization device of GuoNeng Baotou Coal Chemical Co., Ltd. has been in continuous operation for 754 days, continuously setting new records for the long-cycle operation of similar devices in China.

On November 1, 2020, the project started construction, and everyone involved in the project began a race against time. The earlier the project is completed and put into operation, the earlier the zero emission of high-salt wastewater can be achieved. Towards this goal, the project team worked day and night, without holidays, implementing a "5+2" and "day plus night" work system with all staff leaving work at 10 pm. Personnel at the construction site participated in the project construction process in advance, participating in the inspection and rectification of problems throughout the process, and raised more than 2,000 rectification issues in total. Professionals participated in the project commissioning in advance, leading the entire process of device flushing, trial operation, and start-up, and carried out pipeline flushing and instrument debugging work in advance, effectively accelerating the construction progress and saving a lot of time for the project start-up.

On July 3, 2021, after a 9-month construction period, the first pipeline began flushing. On August 27, the pretreatment, membrane treatment, and sludge treatment units were put into operation, producing qualified regenerated recycled water; on October 29, qualified sodium chloride and sodium sulfate salts were produced, and the zero wastewater discharge project was successfully started up at once. On November 18, Baotou Chemical achieved the great feat of zero wastewater discharge.

Racing against time and striving for efficiency in production. From construction to commissioning, the high-salt water salt crystallization device took only 11 months. The sodium chloride and sodium sulfate systems took only three days from feeding to product output. The purity of the sodium chloride product is 98.7%, and the purity of the sodium sulfate product is 99.1%, higher than the first-grade indicators of coal chemical by-product industrial sodium chloride dry salt and first-grade sodium sulfate, far ahead of similar devices in China, and is the best representative of Baotou Chemical's speed and quality.

From the start of operation to the present, the high-salt water salt crystallization device has achieved remarkable results. As of September 20, 2023, the high-salt water salt crystallization device has been stably operating for 754 days, cumulatively reducing high-salt wastewater by about 4.896 million tons, reducing the amount of waste salt hazardous waste by more than 5,509 tons, producing 27,520 tons of high-quality salt, including 10,800 tons of sodium chloride and 16,720 tons of sodium sulfate, achieving economic benefits of more than 61.1 million yuan, and significantly improving water-saving, environmental, and economic benefits. (Zhang Xiaogang Nie Shaofang)