1. Desulfurization wastewater treatment technology
Coal-fired power plants are facing increasingly stringent environmental protection requirements. Optimizing the power plant wastewater treatment process and realizing the resource utilization of wastewater is the only way for thermal power plants to develop into an environment-friendly and resource-friendly enterprise. Jiangsu Kenchuang Environmental Technology Co., Ltd. has proposed a new desulfurization wastewater treatment process route, which can realize the resource utilization of desulfurization wastewater and realize zero discharge of wastewater. Our company cooperated with Guohua Taicang Power Generation Co., Ltd. on the technological innovation of this project. From May 2015 to December 2016, the industrial application test was carried out in Guohua Taicang Power Plant, and the expected effect was achieved.
The technological route design is as follows:
Key technology:
1. Large-scale concentration and weight reduction, the concentration ratio is 1:10~1:15. The fresh water meets the reuse standard and meets the process water requirements of the desulfurization system. The acid-base generated by bipolar membrane electrodialysis of concentrated brine can be reused in the power plant's own system, and can also be used in other industrial applications.
2. Pretreatment unit, the water quality after pretreatment meets the water quality requirements of various membrane treatments. Use a special agent to remove hard and complex heavy metals, while reasonably controlling the pH of the water.
3. The solid matter produced by the pretreatment unit is no longer dissolved, and the solid matter can enter the gypsum dehydration system for dehydration treatment, and no desulfurization wastewater sludge is produced.
2. Test run of a power plant
Test purposes
1. To test the scientific feasibility of the technological route of wastewater treatment;
2. To test the efficacy of pharmaceuticals in the pretreatment process of wastewater treatment and to evaluate their economical use;
3. To verify the maximum degree and stability of membrane reduction;
4. Inspect the quality, effect and economy of converting waste water at the end of the process into acid and alkali;
5. To test the stability, reliability and economy of the operation of the system device.
Reuse water quality target
|
serial number
|
project
|
unit
|
Estimated content
|
|
1
|
PH
|
|
6～9
|
|
2
|
Suspended solids (SS)
|
mg/L
|
≤50
|
|
3
|
Chemical Oxygen Demand (COD)
|
mg/L
|
≤100
|
|
4
|
Sulfide
|
mg/L
|
≤1.0
|
|
5
|
Fluoride
|
mg/L
|
≤15
|
|
6
|
Chloride ion (Cl-)
|
mg/L
|
≤100
|
|
7
|
Total copper (Cu)
|
mg/L
|
≤2
|
|
8
|
Hexavalent chromium (Cr6+)
|
mg/L
|
≤0.5
|
|
9
|
Total Arsenic (As)
|
mg/L
|
≤0.5
|
|
10
|
Total lead (Pb)
|
mg/L
|
≤1
|
|
11
|
Total Nickel (Ni)
|
mg/L
|
≤1
|
|
12
|
Total Zinc (Zn)
|
mg/L
|
≤2
|
Operation conclusion and test report
1. The process route runs smoothly, the technical route is scientific and reasonable, and the whole process can realize automatic control.
2. The pretreatment process of this process has a good effect of using chemicals, and the control method is simple and effective, which can realize automatic drug dosing control, and there is room for formula adjustment and optimization, further reducing operating costs.
3. In this process, the layered and segmented combination of ED membrane, RO membrane and bipolar membrane can ideally achieve the effect of reducing the amount of desulfurization wastewater treatment, and the quality of the produced water is high, which can be directly reused in production. The series of equipment are conventional equipment, the market application is mature and reliable, and it is easy to purchase;
4. The by-products at the end of this process are mixed acid with high purity and low-concentration lye, which can be reused.
5. The operation of this system is relatively simple, and the equipment has good stability. After industrial application, the operating cost should be less than 40 yuan/ton, and the economic efficiency is better than that of the evaporation crystallization treatment process, and has good economic efficiency.
6. This small-scale test has ideally realized the reduction of desulfurization wastewater treatment, the concentration ratio can reach 10-15 times, and the fresh water reuse rate is greater than 90%.
7. Some test reports
Three, targeted technology
According to the actual desulfurization wastewater operation status of a power plant, the design process is for reference.
