The compressed air freeze dryer is referred to as the cold dry machine. The compressed air production system is applied in the project. It is the subsequent processing equipment for the compressed air produced by the air compressor. It is arranged in front of the air compressor and compressed air storage tank. The cold dryer uses the refrigeration principle to freeze and dry the compressed air. E-3. The dry ash conveying system in the paper uses JAL series combined compressed air dryer, which is manufactured and installed by Hangzhou Jialong Gas Equipment Co., Ltd. 1 Working principle Our factory dryer system is engaged in dust removal technology and management of power plants according to the principle of freezing and adsorption drying. The compressed air is cooled to a certain dew point temperature, and the water content in the compressed air tends to be saturated, thereby precipitating the corresponding moisture, performing gas-liquid separation through the separator, and then entering the adsorption tower for deep drying under pressure swing adsorption. The liquid water is discharged through an automatic drain valve, and the regeneration gas carries water vapor and is discharged to the atmosphere through a rear exhaust muffler. The system is mainly divided into two parts: air system and refrigeration system. Principle of air system: The compressed air at the outlet of the air compressor passes through the two-stage filter in front of the dryer, and then enters the pre-cooler to exchange heat with the dry compressed air from the adsorption tower to remove part of the water and reduce the load on the evaporator. . The air after preliminary treatment enters the evaporator for heat exchange, and is cooled to a dew point temperature of about 0 °c to achieve purification and separation of steam and water. The treated compressed air enters the adsorption tower for pressure swing adsorption treatment, and then returns to the precooler to cool the hot and humid air while raising its own temperature, which is beneficial to the regeneration tower gas. The warmed air also prevents condensation on the pipe itself. Principle of refrigeration system: The principle of refrigeration system is the same as that of conventional refrigeration cycle. The cold source uses closed circulating cooling water from the steam turbine side of the power plant. The refrigerant used is R22. The main component of the refrigeration system is the refrigeration compressor (compression process). ), closed cycle cooling water system (condensation process), expansion valve (expansion process), 2 system maintenance and maintenance experience In the daily work process, the main work of the dryer system is as follows: 2.1 cold dryer three-stage filter regularly Maintenance of the dryer filter has three levels, the front two stages, the rear two-stage pre-filter three-stage filter built-in three-stage filter specific model specifications see the name specification model unit number position water filter before the filter The first stage of the degreasing filter has a front-stage second-stage dust-removing filter. The function of the rear pre-stage filter element is to reduce the workload of the main body of the dryer. The main function of the rear filter element is dust removal. (Approx. half a year) Replace the filter element once. In the summer, the load of the unit is high during heavy load, and the amount of compressed air processed by the dryer is large; in winter, a large amount of water is condensed, and the filter effect of the filter is not good, which has a great influence on the dryer, and it is easy to cause evaporator knot due to excessive accumulation of low-temperature water vapor. Frost. Therefore, the professional arrangement is to replace the filter elements one by one before the coming of the summer in May, and before the winter of November. 2.2 Electronic Drain Valve Maintenance There is an electronic drain valve installed under each of the three-stage filter. When maintenance personnel conduct daily inspections, manually test the electronic drain valve and tap the outer casing of the filter body to determine whether the filter has accumulated water. Once the electronic drain valve test fails or the filter accumulates water, it indicates that the electronic drain valve is faulty, and immediately open the work ticket to repair or replace the drain valve. Usually, the electronic drain valve screen is cleaned first, and the internal electromagnet is cleaned. If it still cannot work normally after reloading, arrange the valve body replacement. 2.3 Refrigerant parameter adjustment The main refrigerant parameters in the daily inspection process are the refrigerant high pressure, the refrigerant low pressure and the evaporation temperature. The normal operating range of the refrigerant high pressure is 1.2 ~ 1.7MPa, the normal operating range of the refrigerant low pressure is 0.35~0.45MPa, and the normal range of evaporation temperature is -5~15°C (the ideal range is 0~5°C). When the parameter deviation occurs, the refrigerant high pressure is adjusted by adjusting the opening of the cooling water valve; the opening of the thermal expansion valve is adjusted to adjust the low pressure of the refrigerant; the expansion valve is mainly adjusted, and the range of the evaporation temperature is adjusted by adjusting the cooling water valve. 3 air compressor frequent loading and unloading fault handling air compressor system frequent loading and unloading faults are not in the air compressor itself, the greater possibility is due to excessive resistance of the dryer system, air circulation is not smooth, resulting in air compressors The pressure, loaded to an unloading pressure of 0.72 MPa, resulted in pressure relief. The reason for the excessive resistance of the dryer and the system is usually the frosting of the evaporator application energy technology, which is especially noticeable during the low temperature season in winter. When the defect occurs, the on-site inspection will find that the temperature of the evaporator drain pipe of the dryer is low. When the manual drain door is opened, the drainage can be found to be not smooth, the evaporator body temperature is low, the evaporation temperature is below the degree, and the refrigerant low pressure is low. As shown. The manual drain valve and pipeline connected to the evaporator take measures to stop the operation of the air compressor system, keep the valve of the manual drain line of the evaporator in the normally open state to defrosting, and disassemble to clear and clear the evaporator. After completing the above work, re-enable the equipment, adjust the thermal expansion valve online, adjust the low pressure of the refrigerant to the ideal value of about 0.42MPa, and raise the evaporation temperature to 0~2°C. If the effect is still not ideal, frequent loading and unloading phenomenon If it does not disappear, check the air compressor system itself. Focus on the minimum pressure valve of the air compressor system. If there is a jam, replace the valve. After completing the above work, if the phenomenon of frequent loading and unloading has not disappeared, you should contact the equipment manufacturer for technical support. In this case, it is preliminarily judged that the evaporator of the dryer is clogged and needs to be cleaned or replaced. The disassembly process needs to be carried out under the guidance of the manufacturer's technician. 4 Drainage system transformation Originally the dryer system of the dryer, the outlet of the condenser and the outlet of the evaporator is a plastic hose connection, and the silencer is directly installed at the outlet of the pneumatic valve at the rear of the A and B towers of the dryer. The drain of the drain system condenser and the outlet of the evaporator are connected by plastic hoses. The plastic hoses are often damaged and the tightness is not high. Water is often overflowed during manual drainage. The volume of the muffler housing is too small. When the A and B towers are switched, a large amount of water is sprayed and splashed onto the ground. At the same time, the corresponding diversion trough is lacking, and the accumulated water cannot be drained in time. Defects in the drainage system have a certain negative impact on civilized production, and there is a need to carry out transformation. Professional measures are taken to replace the drain connection hoses of the condenser and evaporator with a four-pipe connection. The outlets of the four dryers A and B of one unit are connected by a new main pipe, and four muffler are installed at the outlet of the main pipe. At the same time, the outer casing of the muffler is made of stainless steel plate, and the drain port is expanded. A small hole is opened in the lower part of the tank for drainage. After the transformation, the surface sewage was significantly reduced, and the level of civilized production on the site was greatly improved. The following is a picture of the scene after the renovation. As shown. The modified cold-drying machine drainage system 5 summarizes that the plant management personnel (inspectors) and maintenance personnel of the power plant have close contact with the cold-drying equipment during the normal working process, so they have strong practical experience. However, the system of the dryer is very precise, and its theoretical principle is more complicated than other equipment. The theoretical basis of the field staff is not solid enough. Therefore, as an inspector, while enriching his own practical experience, he needs to strengthen his own theoretical study, lay a solid foundation, and strengthen regular training for maintenance personnel. At the same time, strengthen the communication of the peers of the brothers, and actively request the technical support of the professionals of the manufacturers and scientific research institutions to improve the overall management level of the dryer system. City eBike 26'' City eBike 26'' beautifully designed, purpose built electric bike well suited to urban riding or commuting. OVERFLY is the electric bike brand of China. Since its establishment in 2005, Overfly focus on the R&D and manufacturing of electric bike and electric scooter ever since. With years development, Overfly electric bike successfully expanded to European, North American and Oceania markets, and occupied a certain market share. 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