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Steel plant circulating water treatment equipment
Basic equipment configuration:
Product name: circulating water treatment equipment in iron and steel plant
Water inlet diameter 25-10000 (mm)
Water production 0.5-1000 tons Working pressure 150 (psi)
Raw water: 80 tons / hour self-provided source well water (an engineering case in Henan)
Water production use: Cooling circulating water for steelmaking process Water production: Reverse osmosis effluent water ≥80T / h
System desalination rate: ≥97%
System configuration: pretreatment + reverse osmosis desalination operation mode: process parameters of automatic control operation equipment meet the "Design Specification for Industrial Water Softening Desalination" (GBJ109-87)
The installation and debugging of the equipment meets the "Code for Construction Acceptance of Water Supply and Drainage Engineering" (GB1328-1995).
Other design basic conditions involved will be determined in the technical discussion
Water inlet pipe: The water inlet pipe is connected to the inlet of the original water pump.
Power supply cable: According to the calculated capacity, the user sends power to the operation and control cabinet.
Outlet pipe: to pure pool. (See process flow chart for details).
Foundation requirements: Foundation bearing capacity ≥ 5 tons / square meter Wastewater treatment: drain to the equipment room trench (considered by users).
System water temperature: normal temperature.
本工艺包括预处理部分、反渗透部分。 The following is the process description part: This process includes a pretreatment part and a reverse osmosis part.
The composition and purpose of the pretreatment and reverse osmosis part: to provide qualified inlet water for the reverse osmosis device.
A. Water inlet requirements of reverse osmosis system:
1) Pollution index SDI≤4
2) Free chlorine <0.1 ppm
3) Turbidity <1NTU
4) Water supply Fe3 + ≤0.01ppm
5) The suitable range of water temperature is 10 ～ 30 ℃
6) Calcium carbonate saturation index LSI 0
B. Pre-treatment is to make the reverse osmosis water into the above requirements through filtration, adsorption and other methods to achieve the following purposes:
1) Prevent scaling on reverse osmosis membrane (including CaCO3, CaSO4, SrSO4, CaF2, SiO2, iron-aluminum oxide, etc.);
2) Prevent fouling of colloidal substances and suspended solid particles on reverse osmosis membranes;
3) Prevent fouling and degradation of reverse osmosis membranes by organic substances;
4) Prevent the fouling of reverse osmosis membrane by microorganisms;
5) Prevent the oxidative damage of reverse osmosis membrane by oxidizing substances;
C. The composition of the pretreatment system:
Raw water contains various impurities such as suspended matter, colloids, organic matter and inorganic matter. In order to remove suspended matter, colloids, organic matter, etc., the raw water pretreatment part is provided with mechanical filters, activated carbon filters, security filters and other devices.
Mechanical filters and activated carbon columns can effectively remove suspended solids, colloids, organic matter and other impurities in the water, and adsorb humus, color, odor, residual chlorine, etc. in tap water, which can reduce water turbidity and pollution index. After its treatment, The clean water has no odor and is called clear water. The mechanical filter is filled with anthracite and quartz sand, and the activated carbon filter is filled with high-quality activated carbon.
Raw water pretreatment part:
Raw water contains various impurities such as suspended matter, colloids, organic matter and inorganic matter. In order to ensure the normal operation of the pre-salt part of the reverse osmosis in this system, the suspended matter, colloids, organic matter, etc. in the water must be removed first to make the infiltration of the reverse osmosis meet the requirements. The raw water pretreatment part includes mechanical filters, activated carbon filters, security filters, anti-scaling and medicinal equipment.
(1) Mechanical filter:
The reverse osmosis equipment has higher requirements on the turbidity of the inlet water, especially the pollution index SDI value of the reverse osmosis inlet water is required to be less than 4, and the turbidity is less than 1NTU. The media in the multi-media filter includes five types of quartz sand, which are used to remove suspended matter in the raw water and the colloid after destabilization. It is sent to activated carbon filter and security filter for further treatment as reverse osmosis equipment inlet water.
(2) The activated carbon filter reverse osmosis equipment requires the residual chlorine content of the incoming water to be less than 0.1mg / l. Therefore, the activated carbon filter is used to remove residual chlorine in the raw water to prevent the reverse osmosis membrane from being polluted. At the same time, it can further adsorb organic matter in raw water. The activated carbon filter is filled with refined shell-shaped activated carbon, which is used to adsorb residual chlorine, organic matter, some pigments and harmful substances in raw water, and reduce chemical oxygen consumption COD. Activated carbon is widely used in the purification of domestic water and industrial water such as food industry and chemical industry. Due to the large specific surface area of activated carbon, its surface is covered with micropores with an average of 20-30 angstroms. Therefore, activated carbon has high adsorption. ability. In addition, the surface of activated carbon has a large number of functional groups such as hydroxyl and carboxyl groups, which can chemically adsorb organic substances of various properties and electrostatic attraction. Therefore, activated carbon can also remove humic acid, fulvic acid, lignosulfonic acid, etc. Organic substances can also remove substances such as residual chlorine that are harmful to the reverse osmosis membrane and prevent the reverse osmosis membrane from being oxidized. It can usually remove 63% —86% of colloidal material, about 50% of iron, and 47—60% of organic material.
The process of removing residual chlorine from activated carbon is a simple redox process. This process may break the activated carbon, but the broken activated carbon does not affect the effect of removing residual chlorine, so the effect of removing residual chlorine from activated carbon is very strong.
(3) Security filter:
The security filter is a microfiltration device and plays a safety role in the pretreatment system. When the mechanical filter works abnormally, it is checked. In order to ensure that it can provide qualified water supply under any circumstances, prevent particles in the water and pipeline from entering the pump and reverse osmosis. System, specially set security filter as the final filtering device. When the pressure difference between the inlet and outlet of the filter is greater than 0.1Mpa, the filter element needs to be replaced (because the filtered medium directly enters the gap of the microporous filter membrane, it is difficult to restore the flux by acid-base cleaning). The filter structure can meet the requirements for quick replacement of the filter element.
Reverse osmosis desalination part:
Water contains various inorganic salts, which cannot be removed by ordinary filtration. However, it is removed by traditional ion exchange methods, but it faces problems such as large acid and alkali consumption, short regeneration cycle, high labor intensity and serious environmental pollution. Osmosis technology is a new high-tech that has emerged in the past two decades. It uses the principle of reverse osmosis and uses a highly selective permeability reverse osmosis membrane to enable the removal of inorganic salts in water to reach 99%. Therefore, it has the advantages of simple operation, low energy consumption, no pollution, etc., and is widely used in the preparation of pure water.
Composition and function of reverse osmosis desalination system:
(1) High-pressure pump:
The setting of the high-pressure pump is to make the inflow of reverse osmosis reach a certain pressure, so that the reverse osmosis process can be carried out, that is, to overcome the osmotic pressure and allow water molecules to pass through the reverse osmosis membrane to reach the freshwater layer.
(2) Reverse osmosis membrane module and pressure vessel:
The reverse osmosis device can remove most of the inorganic salts, particles, bacteria, viruses and other soluble substances in the water.
The reverse osmosis membrane element uses the AG8040-400 low-salinity and low-pressure membrane produced by the American GE company, and the material is an aromatic polyamide composite membrane.
The operating conditions of this membrane element are: Z high temperature 45OC, pH range 2.0-11.0, Z high operating pressure 4.16MPa, Z large pressure loss 0.07 Map, water inlet Z high pollution index SDI 5 and water inlet Z high turbidity 1.0NTU, high residual chlorine content of 0.1ppm in inlet Z, and the flow ratio of single concentrated water to permeate water is 5: 1.
Under normal use, the average service life of the membrane element is 3 years. The design working pressure of this membrane element is in the range of 1.4-2.2 Map. The pressure vessel is the shell that provides the working pressure environment for the reverse osmosis membrane element. It adopts Hidson FRP 8 "-6W pressure vessel from Canada, with a rated working pressure of 300PSI, which is 2.0Mpa. One pressure vessel can hold 6 reverse osmosis membrane elements.
(3) Automatic flushing device:
During the operation of reverse osmosis, the concentration process and concentration polarization will cause the solid content concentration of the raw water in contact with the membrane surface to be much larger than the bulk concentration of the raw water. Therefore, the automatic low-pressure flushing device is equipped to perform regular low-pressure flushing on the reverse osmosis membrane before starting, after shutdown or after an adjustable period of continuous operation, to flush away a small amount of pollutants attached to the membrane surface. After the flushing is completed, the system automatically returns to the state before the flushing was started. The reverse osmosis device is equipped with an automatic low-pressure flushing protection device made in Germany. When the reverse osmosis is turned on, the device automatically flushes the membrane to ensure that the membrane pollution is reduced.
采用反渗透膜元件，压力容器等设备，配以合理而又有前处理和后处理设备，能生产出符合钢铁行业中,钢铁循环冷却标准的水。 Features: Using reverse osmosis membrane elements, pressure vessels and other equipment, with reasonable pre-treatment and post-treatment equipment, can produce water that meets the steel industry's steel cooling standard for circulating cooling. The control system adopts industrial computer program control, which can realize automatic start and stop, dosing and flushing, and automatically monitor various operating parameters for production management.
Related Standards: Water Pollutant Discharge Standards for the Iron and Steel Industry