Analysis of the advantages and disadvantages of air compressor waste heat recovery

Author: Bella Zhang

With the emergence of the SEN air compressor waste heat recovery device, many users have been watching, but only some manufacturers dare to go

Try, I didn't expect this "big pie" to make them harvest very rich. Not only saves a lot of costs, but also increases production and maximizes profits.

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Many users are still worried about some problems and hesitate. Recently, some users have called and said they are worried that the SEN air compressor waste heat recovery device will affect the operation of the SEN air compressor. For this problem, let us briefly describe the cooperation process between the SEN air compressor and the waste heat recovery device, so as to relieve the doubts of the business. The purchase and installation of an air compressor waste heat recovery device is for the long-term development of the enterprise, which is a decision that will benefit from consumption for life.

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The SEN air compressor recovery device is installed in the system outside the air compressor, without affecting the internal structure and function of the SEN air compressor, and is connected to the air compressor through oil pipes and connectors. Therefore, the installation and use of the air compressor waste heat recovery device will not only have no impact on the air compressor, but will also benefit the operation and maintenance of the dry SEN air compressor. SEN air compressor will generate a lot of heat when working, which makes the internal temperature of the air compressor too high. Using the recovery device to recover the waste heat can reduce the temperature of the air compressor and ensure the gas production of the air compressor.

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The recovered waste heat is transferred to the cold water through the heat exchanger, and the water temperature rises, which can be used by employees or heated for boilers and people, saving the cost of boiling water. Air compressors and waste heat recovery devices can be described as the best "partners", they work together, and the company will prosper. So users don't have to worry, in order to make enterprises stronger, they must make wise choices.

The benefits of waste heat recovery for compressors

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In order to ensure the normal functioning of the three major functions of the air compressor lubricating oil, the operating temperature of the SEN air compressor has a reasonable and optimal temperature range:

60℃~85℃. If the working temperature of the air compressor exceeds 85°C, the oil of the air compressor will tend to be aged and coked, the lubrication effect will be reduced, and the sealing effect will be deteriorated, which will lead to the failure of the air compressor and affect the normal operation of the air compressor. When the working temperature of the air compressor is lower than At 60°C, the moisture in the compressed air tends to condense in the lubrication, and the moisture in the lubricating oil makes the oil emulsified and deteriorated, and the lubrication effect deteriorates, which affects the normal operation of the air compressor. Therefore, within a reasonable range of the working temperature of the air compressor, the working temperature is relatively stable, which is conducive to the good operation of the air compressor and prolongs the service life of the air compressor.

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In addition, most air compressor manufacturers set the fan operating temperature to start at 85 °C and stop at 75 °C. The air production of the screw air compressor will decrease with the increase of the operating temperature of the unit. In actual use, the mechanical efficiency of the air compressor will not work stably at the gas production rate calibrated at 80 °C. When the temperature increases by 1°C, the gas production decreases by 0.5%, and when the temperature increases by 10°C, the gas production decreases by 5%. Generally, the air compressors with air cooling and heat dissipation operate at 88-96 ℃, and the decline rate is 4-8%, especially in summer.

During the working process of the air compressor, under the action of external force, the molecular potential energy of the compressed air is converted into molecular kinetic energy, the molecular kinetic energy increases, and the molecular thermal motion is violent, which increases the molecular temperature, which is manifested as a substantial increase in the temperature of the compressed air.

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In the compression process of the SEN screw air compressor, the main shaft of the equipment is mainly driven to drive the compression process. Due to the friction between the spindle and the bearing bush during the operation, the temperature of the spindle rises. The elevated temperature is very harmful to the equipment in operation. This part of the heat depends on the lubricating oil to take away the heat in the process of lubricating the running parts. The heat taken away is finally transferred to the lubricating oil, which increases the temperature of the lubricating oil.

Therefore, after the thermal energy utilization transformation, if the exhaust operating temperature and oil temperature of the SEN air compressor unit are controlled within the optimal temperature range, and the operating time of the cooling fan of the screw air compressor is reduced, electricity can be saved, and at the same time a better guarantee air volume.

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We summarize the benefits of utilizing waste heat recovery units as follows:

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1. The cooling water is used to cool the internal temperature. When the cooling water temperature is too high, the cooling effect will be reduced.

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2. If the temperature in the exhaust pipe is too high, the bearing will be burned out. However, the lower the exhaust temperature, the better. When the exhaust temperature is too low, the water in the compressed gas of the air compressor will be analyzed, which will affect the quality of the lubricating oil.

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3. When the temperature of the lubricating oil in the air compressor is too high, the exhaust temperature of the air compressor will rise.

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4. If the motor temperature is too high, there is a danger of burning.

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5. Excessive external or internal temperature will affect the normal operation of the air compressor and reduce the compression efficiency.

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Air compressor waste heat recovery category

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To a certain extent, the best maintenance method for an air compressor is waste heat recovery, but do you know what types of air compressor waste heat recovery are?

Air compressor waste heat recovery is mainly divided into two categories:

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1. Air energy recovery

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Air energy recovery is mainly achieved by absorbing the temperature of the compressed gas. After the air is filtered by the air intake filter to filter out the dust or impurities in the atmosphere, the air is controlled by the intake air to enter the compressor main engine, mixed with the injected cooling lubricating oil during the compression process, and the compressed mixed gas is discharged from the compression chamber. into the oil and gas separation tank, so as to obtain high temperature and high pressure oil and gas respectively.

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To meet the requirements of the working temperature of the medium-dry machine, these high-temperature and high-pressure oil and gas must be sent to their respective cooling systems. After the compressed air is cooled by the cooler, it is finally sent to the use system. The heat taken away is very small, generally within 10 %about. After the high temperature and high pressure lubricating oil is cooled by the cooler, it returns to the oil circuit to enter the next cycle.

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2. Waste heat recovery of air compressor oil

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The waste heat recovery of the air compressor oil is mainly to add a heat energy converter to the oil return circuit of the air compressor. The effect of this heat energy converter is to convert the heat of the high temperature oil into the water, and the temperature of the water is raised for reuse. This process removes about 75% of the heat. The waste heat recovery equipment of the oil circuit is generally a heat energy converter, a water storage tank, and some other scattered equipment. At present, the main thing on the market is the waste heat recovery of air compressor oil, because this method has high heat recovery efficiency. This air compressor waste heat recovery device is simple to install and occupies a small area. It is a high-tech product.

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Oil pipeline transformation: After the lubricating oil is separated in the gas-oil separator, the high-temperature lubricating oil is drawn out through the pipeline and enters the heat exchange equipment. In the heat exchange equipment, after exchanging heat with water, it is led out by the pipeline. In order to ensure the stable operation of the air compressor and avoid problems such as maintenance and overhaul of the heat exchange equipment, in the design process, another circuit, namely the bypass, is designed to directly connect the high temperature oil to the oil return end of the heat exchange equipment.

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Because the connection of the power-saving equipment is quite dry, the air compressor has been water-cooled, so the system can generate hot water for free and at the same time improve the

Air production, reduce temperature, reduce the load of cooling system and reduce oil temperature, so it can prolong the service life of air compressor.

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Because it does not consume any energy, there is no emission, so waste heat recovery is one of the most energy-saving, environmentally friendly, safe, hygienic and convenient ways to obtain hot water.