In recent years, with the rapid industrial development, the use of waste heat for heating a medium-sizedair compressor air compressor increasingly widespread application of new problems arising. On the one hand, air compressor work year round, need a lot of cooling water or cooling air. On the other hand, as the people living and working standards, office space heating in winter and daily in hot water needs of health has improved steadily. Meanwhile, the state initiated several energy conservation jobs, which allow people to consider whether more can combine the two, not only can reduce the compressor cooling water / cooling air usage, but also can significantly reduce heating costs .
Operability of the air compressor heat recovery
Air compressor heat recovery principle:
Generally medium-sized air compressor oil cooling system, air compressor work, heat (mainly friction heat), through its own oil circulation system, heat the oil transport to the oil cooler, oil cooler shell is generally type or air-cooled heat exchangers, shell and tube heat exchanger in which the specific cooling water through the oil cooling, cooling water and then through the cooling tower to heat transfer to the outside air. In addition, the air compressor compressed air is hot, must also go through a cooling device before entering the gas pipe to use. Heat equivalent to about two parts add up to the compressor input power of 3 / 4, can be recycled is very big.
Elements
Air compressor generally includes two coolers, oil coolers and air coolers, fuel injection type of compressor oil and air temperatures generally reach 80 to 100 degrees cooler in the two shared a cooling water system ( common configuration), 100kW input power required for each cooling water 1.5l / s, the cooling water temperature rose to 15 degrees, this calculation requires taking the heat for the 70kW, therefore, this part of the energy of all the recycling of limited use, the daily heating and sanitary hot the temperature of the water needs of about 45 to 65 degrees, with the gap between air and oil temperature is 35 to 15 degrees, in line with the basic requirements of heat transfer, is part of the total use. In order not to increase oil and air resistance, better way is to change the form of cooler is divided into segments and low-temperature heat, high temperature heat recovery section for water, low-temperature cooling water with the traditional cooling.
Specific structure
For screw type air compressor, the heat distribution in the oil and air, usually with shell and tube air coolers, air flow within the shell tube, resistance is lower, the water flow in the tube, alteration in the water when the only indoor increase the partition, part of the increase in the head and out of water pipes, some of the heat exchanger can replace the space with warm water because the air outlet temperature is lower, so most of the heat can not be recycled, compressed air for the cooling effect does not affect the recycling 30% of the volume control should be designed for multi-process. Oil temperature is generally 69 to 98 degrees, usually plate or tube heat exchanger, such heat exchangers can also be ordered when required multi-process structure, increasing the part of the heat transfer area used for heat recovery. The current system is redundant for all heat recovery systems, heat recovery may be considered to stop when the work can not but be affected by the host, so the design of heat recovery system to be considered even if not used, the host but also through existing The cooling system work properly.
Control
The old air compressor system has a perfect control system, responsible for maintaining the normal and efficient operation of the system, heat recovery system is a redundant system, so the original air compressor control group without any change. Heat recovery system can be used to control its own temperature control, by monitoring the temperature of the hot water tank to control the heating circulating pump operation, pump operation, heat recovery system is the starting state, when you need hot water temperature is high, you can set the water temperature, increase the number of cycles. For energy conservation, to prevent the compressor is not started and the waste of electricity caused by the pump starts, the exhaust temperature by measuring method for determining the need for circulating pumps working.
Heat recovery system components
Heat recovery systems include heat transfer systems, pressure systems, water, and heat preservation system. Because the air compressor switch is not uniform, and equipment configuration and the factory has a lot to use, so that the heat in unit time is messy, but in the long run is stable heat source. Both heating and sanitary hot water load is not uniform, so in order to ease the conflict, there must be enough heat preservation methods, namely, water tank insulation.
Economic Analysis
100kW of input power per 20% recovery, that is 20kW calculation, the air compressor to run 8 hours a day, you can recycle 160kW of heat, can get 5.5 tons of 45 degree water, while the use of the boiler system to take the same amount of heat If you need to consume fuel 15.4kg of water at 7.2 yuan / kg, the daily can save 111 yuan each year (240 days) to save fuel costs 26,640 yuan. The same amount of hot water electric boilers at least 200 per day, electricity, annual savings of 48,000 yuan.
Air Compressor Heat Pump Comprehensive benefits:
1, the safety, health, convenient and practical. Screw air compressor pump compared with oil-fired boiler, pollution, carbon monoxide, sulfur dioxide, smoke and noise, oil pollution of the atmospheric environment.Once the installation is put into use, as long as the compressor is running, corporate staff to use at any time can be extracted to the water. Do not have to ration time, the system the larger companies also to corporate employees to use hot water to clean slate in winter clothing, bedding. To create a resource-saving and environment-friendly enterprise basis.
2, the economic operation. Improve the efficiency of the compressor, the implementation of the economic operation of air compressor. Most of the factory unit air compressor manufacturer to set the fan starts operating temperature is 85 ℃ heat. Install screw air compressor pump air compressor running temperature of 85 ℃ or less, can reduce the air-cooled screw air compressor cooling fan operation time.
General air compressor are running between 80 ~ 96 ℃, air compressor pump air compressor temperatures drop enough to make 8 ~ 12 ℃ its decline in 4 to 8%, better in summer, for its economic benefits on the more notable.
3, the reduction of air compressor maintenance costs. Air compressor operating temperature decreased, reducing the machine'mp;as failure to extend the life of the equipment, reduce maintenance costs, increased oil, Oil Filter, oil and gas separator replacement time limit is extended replacement period. Screw air compressor main payment, the running costs, are high-cost equipment, followed by the replacement of supplies, oil, Oil Filter, oil and gas separator. Example of a 37kW screw air compressor imported supplies and maintenance costs are about a 4,700 yuan, the use of the 3000H, consumable costs 1.56 yuan / hour.Between 80 ~ 84 ℃ in the air compressor running, supplies 35% of extended use of the same period, the 4050H, postponed after the fee is 1.16 yuan supplies / h. Within the air compressor to run at 85 ℃ to prevent oil emulsification, coke formation, decrease, both are severely affected by oil filter, oil and gas sep