1 AEC water treatment technology
AEC water treatment technology is a comprehensive water treatment technology, including corrosion, scaling and microbial control, automatic analysis system and dosing system, so that the circulating water system can run safely and stably for a long time. The technology adopts patent products without phosphorus, and the agent has the characteristics of hydrolysis resistance, oxidation resistance and decomposition, and has good solubility and stability, which can effectively control calcium carbonate scaling, delay equipment corrosion, stabilize colloidal particles in water and prevent scaling and deposition.
(1) Improve the concentration multiple of circulating water, reduce the make-up water, reduce sewage discharge, save water resources, and reduce the water treatment cost by reducing the consumption of water treatment chemicals.
(2) The corrosion rate decreases.
(3) As an inhibitor of bacteria and microorganisms, liquid chlorine can kill bacteria and control microorganisms by continuous or regular dosing, so as to maintain the residual chlorine in the system and ensure that the microbial content in the system is always kept at a low level.
(4) It has good dispersion and scale inhibition ability and good solubility.
(5) All the treated sewage can be reused as make-up water of the circulating water system, which reduces the make-up amount of fresh water and realizes zero discharge.
AEC circulating water treatment technology has the characteristics of non-decomposition, non-hydrolysis and anti-oxidation. Suitable for operation in the environment with high alkalinity, high hardness and high concentration multiple. Good anti-corrosion, anti-scaling and microbial control effects, water saving, energy saving, environmental protection, high degree of automation, improved heat exchange efficiency, more professional management and obviously improved indirect benefits. This is a new water-saving technology.
2 open circulating cooling water system
2. 1 principle
After heat exchange, the cooling water is evaporated and cooled by the borrowed water for recycling. Through the contact between water and air, the cooling of circulating water is realized through three processes, including contact heat dissipation, evaporation heat dissipation and radiation heat dissipation.
2.2 classification
According to the different contact modes between hot water and air, the cooling system can be divided into cooling pool and cooling tower.
2.2. 1 cooling pool natural cooling pool and spray cooling pool.
2.2.2 cooling tower a. natural ventilation cooling tower: open and ventilated; B. Mechanical ventilation cooling tower: blast type and exhaust type.
2.3 Cooling circulating water is easy to cause problems in the process of recycling.
2.3. 1 Evaporation and concentration of scaling circulating cooling water, carbon dioxide loss, water temperature change, insoluble matter generated by chemical reaction, and water pollution.
2.3.2 Corrosion Chemical corrosion, electrochemical corrosion and microbial corrosion.
2.3.3 Microbial breeding and mud sticking
2.4 Water quality indicators
In order to prolong the long-term operation of equipment and effectively control the above problems, water quality indicators should be strictly controlled in daily operation. The following are the main indicators of circulating cooling water quality:
2.4. 1 PH value forms an oxide protective film on the metal surface, which is easy to passivate. When circulating cooling water runs at high PH value, it can effectively reduce the occurrence of system corrosion.
2.4.2 The turbidity of fresh water is poor, the bypass filter does not work well, and the growth of microorganisms will cause the suspended matter and turbidity of circulating water to exceed the standard.
2.4.3 Fouling thermal resistance Due to the deposition of deposits on the heat transfer surface of the heat exchanger, the heat transfer coefficient decreases and the thermal resistance increases. Whether dirt adheres to the heat exchanger depends on the flow rate, speed, chemical concentration and microbial growth.
2.4.4 Concentration multiple represents the reuse rate of water, which is the ratio of ion concentration of circulating water to ion concentration of make-up water, and is restricted by water quality standards of make-up water and circulating cooling water. Under the condition of ensuring the treatment effect, the concentration multiple should be increased as much as possible to reduce the discharge of make-up water and sewage.
2.4.5 Iron ions Generally speaking, iron ions will appear in circulating water with low PH value, and the existence of iron ions is one of the signals of corrosion in circulating water system.
2.4.6 Calcium ion circulating water contains certain calcium ions, which is beneficial to slow down corrosion.
2.4.7 alkalinity In order to prevent the alkalinity from rising, acid treatment can be added.
In order to effectively reduce corrosion, scaling and microbial growth and ensure the daily operation process, it is necessary to add certain scale and corrosion inhibitors. Commonly used corrosion inhibitors include polyphosphate, orthophosphate, pyrophosphate, organic phosphate, chromate, benzotriazole and so on.
3 Circulating water treatment station
The circulating water treatment station of cold rolling plant includes the following systems: circulating water system, emergency water system, supplementary water system, domestic water system, fire water system, filtration system, water quality stabilizing dosing system and cooling system. Let's briefly introduce the circulating water system.
3. 1 water supply system
The system is responsible for providing sufficient pressure and stable circulating cooling water to users of each unit, and is the main component of the circulating water treatment station. The water supply pipeline is equipped with valves, automatic pressure-maintaining hydraulic butterfly valves and ripple compensators to buffer water and water pressure.
3.2 backwater system
The backwaters of users from all units are finally collected in the return pipe, and then cooled in the cooling tower for water quality treatment of suction wells.
3.3 Bypass filtration system
Mainly responsible for filtering circulating water.
4 conclusion
Circulating water treatment technology is a comprehensive treatment technology with many contents and complicated processes. With the rapid development of industry, the problems of water pollution and water shortage have become increasingly prominent, and improving the reuse rate of sewage has become one of the main methods to solve the contradiction between supply and demand. Improving the circulating water treatment technology can not only ensure the safe and normal operation of the unit, but also be of great significance for rational water use, increasing the concentration ratio of circulating water, saving water resources and reducing sewage discharge.
The above are collected and sorted by Zhong Da Consulting Company.
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