Design Analysis of Compressed Air Station in Cement Production Line Zhang Chunjing S Zhang Songyu 2, Xiang Lai 2, Tang Zhanqi 2 (1. Luoyang Ruize Petrochemical Engineering Co., Ltd., Luoyang, Henan 471003, China; 2. Luoyang Cement Engineering Design and Research Institute Co., Ltd., Luoyang, Henan 471003, China) Production line typical compressed air process flow Table 1 a 3000t / d production line compressed air station equipment configuration table name model and specifications screw air compressor displacement: 20m3 / min, exhaust pressure: 0.75MPa, conveying medium: compressed air, Cooling method: air-cooled, starting mode: star-A start supporting motor power: 110kW, speed: 1450r/min, power supply: 380V/50Hz buffer tank Specifications: D1000, diameter: 1 working pressure:. 85MPa, volume: 2m3 dust filter Specifications: DN80, processing capacity: 25m3 / min, working pressure:. 8MPa, filter oil content: 矣lppm, filtration accuracy: 矣l (m micro oil filter specifications: DN80, treatment capacity: 25m3 / min, working pressure: 8MPa, filter oil content: O.Olppm, filtration accuracy: dryer Rated treatment capacity: 25m3/min, working pressure: 0.8MPa, regenerative gas consumption: 矣7%, intake air temperature: 矣45弋, 1 design principle of compressed air station in cement production line Compressed air system is compressed air station, outdoor compression The air duct, the workshop inlet device and the internal compressed air pipeline are composed of four parts. At the beginning of the design, the form of the compressed air system must first be determined, which can be selected according to the following principles: pressure. The gas pressure for cement production is mostly 0.5~0.8MPa. Generally, the design pressure is selected according to the maximum gas supply of 0.8 MPa, and then the pressure is reduced according to different pressure requirements at the entrance of each workshop.
Use gas quality. Subsequent processing equipment is selected according to the requirements of each workshop for the quality of compressed air (dryness, water content and oil content). Most of the gas used in cement production is instrumentation, valve control, pulse injection and air cannon. The general design can be based on the same air quality (the dew point is lower than the ambient temperature lower limit of 10. The dust particle size should not exceed 3xm, and the oil content should not be More than 10mg/m3), that is, centralized treatment in the compressed air station.
Load characteristics. According to factors such as the gas period of compressed air in the production area, the amount of gas used, and the distance, the number of compressed air stations and the total map position are determined to achieve an economical and reasonable configuration. Generally, two compressed air stations (one set of clinker line and grinding system) are set up nearby. If the gas point of the workshop is far away from the compressed air station, a gas storage tank should be set near the gas point (outside the workshop) to balance Gas volume, stable pressure.
2 Process flow and typical configuration There are many types of air compressors, such as screw type, piston type, centrifugal type, and spiral type. The screw air compressor is widely used in cement engineering. The air cooling method is water cooling and air cooling. The temperature of the compressed air discharged from the cylinder before cooling is 180, and the temperature after cooling by the cooler is about 40. Since the air in nature is humid air, when the humid air is compressed, its pressure increases and the temperature rises, but it is still unsaturated humid air. If it is cooled by the cooler, the air temperature is lowered, and then the compressed air is contained. The water vapor becomes supersaturated.
Therefore, it is necessary to carry out the necessary degreasing and drying treatment of the air compressor outlet gas, so the general compressed air treatment process also needs to add some necessary auxiliary post-processing equipment.
See the typical compressed air process for cement production lines.
The typical compressed air station equipment configuration for the 3000t/d production line is shown in Table 1. Note: The table is a configuration of a compressed air system with 3 sets of compressed air systems.
3 design process should pay attention to the problem of compressed air station plant design. When the screw air compressor has a displacement of 20m3/min, it should be a separate building. It cannot be placed under the preheater, the precipitator frame or the compression plant size for investment reduction. Under normal circumstances, the net height of the plant should be above 4.5m; for hot areas in summer, the skylight should be set when the span between machines is greater than 9m; the main passage between air compressors should be more than 2m, between air compressors and after treatment The passage between the equipment should be above, the passage between the air compressor and the wall should be above 1.2m; the workshop should also be equipped with lifting equipment to facilitate maintenance and maintenance.
Air distribution in the plant. Especially for the air-cooled screw air Zhang Chunjing, the design and analysis of the compressor of the compressed air station of the cement production line, because the heat generated by it is all discharged by the cold air of the environment, the airflow organization of the plant is very important. It is the airflow organization of a typical compressed air station.
Inlet air = screw air compressor ventilator § Exhaust air compressed air station air flow organization mode Air compressor installation bottom elevation setting. It is recommended to set a concrete platform 100~200mm above the ground to facilitate the discharge of lubricating oil and not directly placed on the indoor floor.
A matching motor for an air compressor. At present, the air compressors on the domestic market are equipped with two types of motors, two-pole or four-pole motors, which correspond to two speeds of 2900r/min and 1450r/min. Relative to the same exhaust pressure, the high speed means the rotor. The wear is faster and the service life of the rotor is shortened. Therefore, the low-speed asynchronous motor should be used as much as possible under the premise of ensuring the compression condition. Although this increases the investment, it is more economical than the frequent replacement of the rotor and maintenance.
The way the air compressor cools. The cooling system is a very important part of the air compressor because the air is compressed to release a large amount of heat, which is carried away by the cooling system for heat exchange. The cooling system is divided into air-cooled and water-cooled. The design selection conditions are as follows: the ambient temperature of the air-cooled screw air compressor cannot exceed 40. The air-cooled cooler is exposed to the air, and the fins will adhere to the dust. If the accumulated dust is too much, the heat transfer effect of the cooler will be seriously affected. Therefore, air-cooled air cleaning is required to be high.
Water-cooled coolers mostly use shell-and-tube coolers. One is a rear cooler to cool the compressed air, and the other is an oil cooler to cool the lubricant before it is sprayed into the body. Water-cooled chillers have no requirements for ambient temperature conditions, but require high cooling water quality. If the water quality is too poor, the chiller is prone to fouling and blockage, or is corroded, resulting in increased maintenance costs and even the borehole of the cooler.
Originally, water-cooled screw air compressors were used in cement projects, but with the continuous improvement of cement production environmental conditions, air-cooled types were gradually promoted. This is determined by the designer based on actual conditions.
The design of the lubricating oil system. Lubricating oils are required to have low air bubbles, low volatilization, high oxidation resistance, high demulsibility, good anti-wear lubricity and water separation. It is recommended to use a blended refined mineral base oil and various synthetic base oils to blend synthetic lubricants. This product has a wider operating temperature range, less sludge and gel formation, and lower oil volatility. In order to reduce the consumption of lubricating oil, the stable performance makes the maintenance cost lower, and the life of the bearing and even the equipment can be prolonged. It has become a universal recommendation and quality assurance product for the screw compressor manufacturer.
Compressed air plant fire protection design. Fire water systems may not be designed, but mobile fire extinguishers must be configured to deal with fires caused by lubricant leaks or improper discharge.
4 Conclusion Compressed air station is a downstream specialty in cement engineering design, and often does not pay attention. However, in the actual production line operation, the compressed air station is a power source in production. It plays a vital role in the anti-blocking and blocking of the preheater, the efficient operation of the dust collecting device, and the safe and reliable operation of the host equipment such as the execution of the pneumatic valve. This paper starts with the engineering design of the compressed air station, and briefly introduces the selection factors of the process flow and the matters needing attention in the design process. It is hoped that the beginning (design) of cement construction can avoid some mistakes, so as to ensure that the production line will not cause major production accidents due to compressed air after it is put into production.
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