JP2021096043A - Exhaust heat recovery system and gas compressor used for the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve an exhaust heat recovery rate and save energy in an exhaust heat recovery system of a gas compressor. SOLUTION: A gas compressor having a compressor body for compressing a gas and outputting the compressed gas, and exhaust heat recovery water for heat exchange with the compressed gas by a heat exchanger for exhaust heat recovery and a heat exchanger are distributed. It is an exhaust heat recovery system having an exhaust heat recovery machine equipped with an exhaust heat recovery liquid pipe, and the compressor main body and the heat exchanger for exhaust heat recovery are connected by a gas pipe through which the gas to be compressed flows. The exhaust heat recovery machine is set to the temperature sensor installed downstream of the heat exchanger for exhaust heat recovery in the exhaust heat recovery liquid piping, the temperature control valve, and the temperature of the exhaust heat recovery water measured by the temperature sensor. It is configured to have a temperature controller that controls the opening / closing angle of the temperature control valve according to the recovered water temperature. [Selection diagram] Fig. 1

Description

The present invention relates to waste heat recovery that recovers and reuses "heat" generated when a gas is compressed in a gas compressor.

A gas compressor that sucks a gas such as air and discharges a high-pressure gas such as compressed air by a compression mechanism is known. In particular, air compressors are used in factory lines and work sites as air sources for machine tools, presses, air blowers, and the like. Here, it is said that the total energy consumed by the gas compressor out of the energy consumed in the entire factory is equivalent to 20 to 25%, and the effect of recovering the exhaust heat from the gas compressor is great. In particular, the use of waste heat from gas compressors is expected to become even more important in the future in order to achieve the CO2 emission reduction target triggered by the problem of global warming.

A gas compressor is composed of a compressor body that compresses a gas such as air, a cooling system that absorbs heat generated by the compression, a motor that is a driving force source of the compressor, and the like. Further, in a gas compressor, when the motor input power is 100%, the amount of heat absorbed in the cooling system corresponds to 90% or more of the amount of heat, and the amount of heat is normally released to the outside air, which is very large. Energy is being discharged into the atmosphere. In order to reduce the amount of exhaust heat, higher efficiency of the compressor body and motor is being promoted, but the effect is limited to a few percent, and effective use of exhaust heat from the gas compressor is required.

Patent Document 1 is a prior art in the present technical field. In Patent Document 1, in an oil-cooled gas compressor, by recovering heat from at least one of compressed gas and oil, it is possible to supply hot water at a required temperature even when the compressor load factor is low, and for circulation. It is disclosed that the exhaust heat recovery rate is improved by suppressing heat dissipation from the exhaust heat recovery device by controlling the rotation speed of the pump.

Japanese Unexamined Patent Publication No. 2014-145273

In the exhaust heat recovery system of Patent Document 1, the rotation speed of the pump is controlled according to the temperature of water in the heat recovery path and the discharged air temperature or the air temperature / oil temperature after passing through the exhaust heat recovery heat exchanger. However, this configuration requires a control device such as a control panel and an inverter panel for controlling the rotation speed of the circulation pump, and has a problem that a large amount of electric power is consumed when the operation and stop are repeated.

In addition, when the flow of compressed air in the compressed air flow path is stopped due to the unload operation, an error occurs between the temperature of the compressed air in the exhaust heat recovery heat exchanger and the temperature of the compressed air detected by the temperature sensor. The pump may malfunction. Along with this, the pump continues to operate until the temperature inside the exhaust heat recovery heat exchanger reaches the compressed air temperature, which requires power consumption.

In addition, since the temperature of the water in the heat recovery path and the temperature of the discharged air or the temperature of the air or the oil after passing through the exhaust heat recovery heat exchanger are judged only, the heat recovery is performed. There is a problem that heat recovery continues even when the temperature of water in the path becomes higher than the temperature desired by the user.

An object of the present invention is to improve the exhaust heat recovery rate and save energy in the exhaust heat recovery system of a gas compressor.

To give an example, the present invention exchanges heat with a compressed gas by a gas compressor having a compressor body for compressing the gas and outputting the compressed gas, and a heat exchanger and a heat exchanger for exhaust heat recovery. An exhaust heat recovery system having an exhaust heat recovery machine provided with an exhaust heat recovery liquid pipe through which exhaust heat recovery water flows, and a gas to be compressed flows through the compressor body and the heat exchanger for exhaust heat recovery. It is connected by a gas pipe, and the exhaust heat recovery machine is a temperature sensor installed downstream of the heat exchanger for exhaust heat recovery in the exhaust heat recovery liquid pipe, a temperature control valve, and exhaust heat measured by the temperature sensor. It is configured to have a temperature controller that controls the opening / closing angle of the temperature control valve according to the temperature of the recovered water and the set recovered water temperature.

According to the present invention, it is possible to provide an exhaust heat recovery system capable of improving the exhaust heat recovery rate and saving energy, and a gas compressor used therefor.

It is a schematic diagram which shows the schematic structure of the exhaust heat recovery system in Example 1. This is a control processing flow for keeping the temperature of the recovered water of the waste heat recovery system according to the first embodiment constant. It is a schematic diagram which shows the schematic structure of the exhaust heat recovery system in Example 2. This is a control processing flow for keeping the temperature of the recovered water of the waste heat recovery system according to the second embodiment constant.

Hereinafter, examples of the present invention will be described with reference to the drawings. In this embodiment, a water-cooled package-type two-stage oil-free screw compressor that compresses air will be described as an example of a gas compressor.

FIG. 1 is a schematic diagram showing a schematic configuration of an exhaust heat recovery system in this embodiment. As shown in FIG. 1, the exhaust heat recovery system 100 includes an air compressor 1 including compressor bodies 21 and 21 arranged inside the housing, and an exhaust heat recovery machine including heat exchangers 31 and 32 outside the housing. It is composed of 2.

Although not shown, the housing is a base on which each device such as the compressor bodies 21 and 22 is installed, and a metal or the like installed on the base so as to cover each device such as the compressor bodies 21 and 22. It has a box-shaped cover composed of multiple panels, and has excellent soundproofing performance.

The compressor bodies 21 and 22 include a pair of screw rotors, a male rotor and a female rotor (not shown). Further, the compressor main bodies 21 and 22 are configured to be driven by, for example, a power transmission mechanism by a traction motor arranged in the housing. The power is not limited to the electric motor, and may be an internal combustion engine or the like.

The compressor main body 21 is a first-stage compressor main body arranged on the upstream side of the air flow, and the compressor main body 22 is on the downstream side of the air flow with respect to the first-stage compressor main body 21. This is the second stage compressor body located in.

Since the compressor bodies 21 and 22 in this embodiment are oil-free screw compressors, they are compressed by the heat generated during air compression, unlike the liquid supply type air compressor that injects a liquid such as oil or water into the compression operating chamber. The machine bodies 21 and 22 tend to generate heat in particular. And since the compressed air has a high temperature, it may not be suitable for use by the demand source of compressed air. Therefore, in the air compressor 1, cooling water is supplied to each part. Further, the air compressor 1 of the present embodiment is configured to be able to recover the exhaust heat generated when the compressor bodies 21 and 22 compress the air so as to be performed later.

The exhaust heat recovery machine 2 includes heat exchangers 31 and 32 for exhaust heat recovery arranged outside the housing. The heat exchangers 31 and 32 include exhaust heat recovery water as an exhaust heat recovery liquid sent from the user side of the exhaust heat generated by the compressor bodies 21 and 22, and compressed air discharged from the compressor bodies 21 and 22. It exchanges heat. The heat exchanger 31 is an intermediate stage exhaust heat recovery heat exchanger arranged between the first stage compressor main body 21 and the second stage compressor main body 22, and the heat exchanger 32 is a heat exchanger 32. This is a heat exchanger for recovering exhaust heat from the discharge stage, which is arranged on the discharge side (downstream side) of the compressor body 22 in the second stage.

Further, the air compressor 1 includes cooling heat exchangers 51 and 52 arranged in the housing. The cooling heat exchangers 51 and 52 exchange heat between the cooling water as the cooling liquid sent from the outside of the air compressor 1 and the compressed air discharged from the compressor main bodies 21 and 22. The cooling heat exchanger 51 is an intercooler arranged between the first-stage compressor main body 21 and the second-stage compressor main body 22 (hereinafter, the heat exchanger 51 is referred to as an intercooler). ), The cooling heat exchanger 52 is an aftercooler arranged on the discharge side of the compressor main body 22 in the second stage (hereinafter, the heat exchanger 52 is referred to as an aftercooler).

Between the compressor main body 21 of the first stage and the compressor main body 22 of the second stage, a heat exchanger 31 for recovering exhaust heat from the intermediate stage and an intercooler 51 are arranged in order from the upstream side. Further, on the discharge side of the compressor main body 22 of the second stage, a heat exchanger 32 for recovering exhaust heat from the discharge stage and an aftercooler 52 are arranged in order from the upstream side. In some cases, the heat exchangers 31 and 32 for recovering exhaust heat may be arranged in the reverse order of the intercooler 51 and the aftercooler 52.

The first stage compressor body 21, the heat exchanger 31 for intermediate stage exhaust heat recovery, the intercooler 51, the second stage compressor body 22, the heat exchanger 32 for discharging discharge stage exhaust heat recovery, and the aftercooler 52 are , It is connected by an air pipe 6 through which the air to be compressed flows.

The above distribution path is during load operation (load operation), and during unload operation (no load operation), the released air is the compressor body 21, the heat exchanger 31, the intercooler 51, and the compressor. After the main body 22 and the heat exchanger 32 have been circulated, the check valve 10 is fully closed by the unload operation, so that the check valve 10 is discharged from the air discharge pipe 4 to the atmosphere. As a result, the exhaust heat can be recovered regardless of the operating state because the blown air flows through the heat exchangers 31 and 32 even during the unload operation (no-load operation), and the exhaust heat recovery rate is improved. Can be planned.

Further, the exhaust heat recovery liquid pipe 7 through which the exhaust heat recovery water that exchanges heat with the compressed air in the heat exchangers 31 and 32 for exhaust heat recovery flows, and the compressed air and heat in the intercooler 51 and the aftercooler 52 for cooling. The coolant pipe 8 through which the replaced cooling water flows is separately arranged in the housing as an independent path.

The waste heat recovery liquid pipe 7 is a heat exchanger 31 for intermediate stage waste heat recovery from the waste heat recovery liquid inflow port 71 into which the waste heat recovery water sent by the operation of the circulation pump 14 from the waste heat utilization side flows in. And, it is connected to an exhaust heat recovery liquid outlet 72 through which the exhaust heat recovery water sent to the exhaust heat utilization side flows out through the heat exchanger 32 for exhaust heat recovery in the discharge stage.

Further, by providing a temperature sensor 11, a temperature controller 12, and a temperature control valve 13 downstream of the heat exchanger 31 for intermediate stage exhaust heat recovery, the flow rate is adjusted according to the exhaust heat recovery outlet temperature. Has been done.

The coolant pipe 8 branches from the coolant inlet 80 into the first coolant pipe 81, the second coolant pipe 82, and the third coolant pipe 83, and then merges with each other to the coolant outlet. It is configured to connect to 84. The coolant inflow port 80 is an inlet outside the air compressor 1 into which cooling water sent from, for example, a cooling tower (not shown) or the like flows. Further, the coolant outlet 84 is an outlet from which the cooling water sent toward the cooling tower or the like flows out.

The first coolant pipe 81 is connected to the coolant outlet 84 from the coolant inflow port 80 via the aftercooler 52. The second coolant pipe 82 is provided from the coolant inflow port 80 to the oil cooler 9, the cooling jacket provided in the casing of the second stage compressor body 22, and the casing of the first stage compressor body 21. It is connected to the coolant outlet 84 via the cooling jacket. The third coolant pipe 83 is connected to the coolant outlet 84 from the coolant inflow port 80 via the intercooler 51.
Although not shown, the oil cooler 9 is a water-cooled heat exchanger for cooling the bearings of the compressor bodies 21 and 22 and the lubricating oil that lubricates the power transmission mechanism and the like. The lubricating oil cooled by the oil cooler 9 lubricates the bearing portions of the compressor bodies 21 and 22 and is then stored in an oil sump (not shown). After that, the lubricating oil is guided to the oil cooler 9 by a transport mechanism such as an oil pump (not shown) to be cooled, and is configured to circulate in this lubricating path.

Next, the operation of the exhaust heat recovery system 100 configured in this way will be described. In FIG. 1, the air compressor 1 sucks air through a capacity adjusting valve (not shown) arranged on the upstream side of the first stage compressor main body 21, and the first stage compressor main body 21 sucks air. Compress the air. After that, the compressed high-temperature air (for example, about 160 ° C.) exchanges the required amount of heat with the heat exchanger 31 for recovering the exhaust heat in the intermediate stage, and is further cooled by the intercooler 51. Here, compressed high-temperature air and exhaust heat recovery water flow through the heat exchanger 31 for intermediate stage exhaust heat recovery to perform heat exchange, and the intercooler 51 is used for intermediate stage exhaust heat recovery. The compressed air whose temperature has dropped due to heat exchange in the heat exchanger 31 and the cooling water flow to exchange heat.

Next, the air cooled by the intercooler 51 (for example, about 40 ° C.) is compressed by the compressor main body 22 of the second stage in order to further increase the pressure. After that, the compressed high-temperature air (for example, about 160 ° C. or higher temperature) exchanges the required amount of heat again with the heat exchanger 32 for recovering the exhaust heat of the discharge stage, and is further cooled by the aftercooler 52. .. Then, the air cooled by the aftercooler 52 (for example, about 40 ° C.) is sent to the demand source of the compressed air.

On the other hand, the exhaust heat recovery water flows in from the exhaust heat utilization side through the exhaust heat recovery liquid inflow port 71 by the operation of the circulation pump 14, flows through the exhaust heat recovery liquid pipe 7, and heat for exhaust heat recovery. After exchanging heat with the compressed air in the exchangers 31 and 32, the recovery temperature is measured by the temperature sensor 11 installed downstream of the heat exchanger 31 for recovering the intermediate stage exhaust heat, and the exhaust heat is exhausted via the temperature control valve 13. It flows out from the recovery liquid outlet 72 toward the utilization side of the exhaust heat. Here, the temperature controller 12 controls the opening / closing angle of the temperature control valve 13 according to the recovery temperature measured by the temperature sensor 11 and the set recovery water temperature, and adjusts the flow rate to keep the recovery temperature constant at all times. .. Further, by providing the temperature controller 12, it is possible to set the required recovery temperature, and it is not necessary to replace the temperature control valve or the like or change the specifications when changing the recovery temperature.

In this way, the recovered water is adjusted in temperature and flow rate by the temperature sensor 11, the temperature controller 12, and the temperature control valve 13 and supplied to the exhaust heat utilization side. Therefore, the exhaust heat utilization side is loaded with the compressor. Even when the compressed air temperature drops due to a reduction in the rate or unloading operation, the exhaust heat recovery water can be used as a heat source for various facilities at a constant temperature.

FIG. 2 is a control processing flow performed by the temperature controller 12 that controls the temperature control valve 13 in order to keep the temperature of the recovered water constant at 90 ° C. in the waste heat recovery system 100 in this embodiment.

Hereinafter, each processing step in FIG. 2 will be described.
S201: When the gas compressor operates, electric power is supplied to the temperature controller 12 and the control of the temperature control valve 13 is started.
S202: The temperature controller 12 acquires the temperature of the exhaust heat recovery water measured by the temperature sensor 11.
S203: When the measured recovered water temperature exceeds 90 ° C., the process proceeds to S204, and the process proceeds to the process of lowering the recovered water temperature. If the temperature does not exceed 90 ° C., the process proceeds to S209. S204: When the temperature control valve 13 is fully opened, the circulation pump 14 is stopped in S207, and a minor failure signal is sent in S208. If it is not fully open, the process proceeds to S205.
S205: The valve of the temperature control valve 13 is adjusted (opening direction) to increase the flow rate, thereby lowering the recovered water temperature.
S206: Waits for a certain period of time and returns to S202.
S209: When the measured recovered water temperature is less than 90 ° C., the process proceeds to S210 to shift to the process of raising the recovered water temperature. If the recovered water temperature is not less than 90 ° C., it is determined that the temperature is constant at 90 ° C., the process proceeds to S206, and the patient waits for a certain period of time to recover the exhaust heat.
S210: When the temperature control valve 13 is fully closed, the S207 circulation pump 14 is stopped and an S208 minor failure signal is sent. If it is not fully closed, the process proceeds to S211.
S211: The valve of the temperature control valve 13 is adjusted (closed direction) to reduce the flow rate, thereby raising the recovery temperature.

In this embodiment, the waste heat recovery water sent from the waste heat utilization side is, for example, high temperature water having a temperature of 70 to 90 ° C. Then, the exhaust heat recovery water, which is high temperature water, is raised in temperature by, for example, about 5 to 10 ° C. by heat exchange with the compressed air in the heat exchangers 31 and 32 for exhaust heat recovery, and the exhaust heat utilization side. Returned to.

Further, the cooling water flows from, for example, a cooling tower (not shown) through the coolant inflow port 80 and flows through the coolant pipe 8, and cools each part in addition to the compressed air in the intercooler 51 and the aftercooler 52. After that, it flows out from the coolant outlet 84 toward the cooling tower. The cooled water whose temperature has risen is cooled by exchanging heat with the atmosphere in the cooling tower.

As described above, according to the present embodiment, as measures for reducing the compressor load factor and lowering the compressed air temperature due to the unload operation, the exhaust heat recovery outlet line has a temperature sensor 11, a temperature controller 12, and a temperature control valve 13. By providing the above, the amount of recovered water can be adjusted and the exhaust heat recovery temperature can be kept constant. Further, the check valve 10 and the exhaust pipe 4 are arranged downstream of the heat exchanger 32 for exhaust heat recovery at the discharge stage, and the exhaust air is the heat for exhaust heat recovery even during the unload operation (no load operation). Since the exchangers 31 and 32 have a structure in which they flow, exhaust heat can be recovered regardless of the operating state, the exhaust heat recovery rate can be improved, and energy can be saved.

In the first embodiment, the temperature sensor 11, the temperature controller 12, and the temperature control valve 13 are used to control the temperature of the exhaust heat recovery water so as to be kept constant at all times. When the temperature control valve 13 is fully open or fully closed and the temperature cannot be adjusted by increasing or decreasing the flow rate, the circulation pump 14 is stopped to output a minor failure signal.

On the other hand, in this embodiment, an example in which the temperature of the waste recovered water can be adjusted even when the temperature cannot be adjusted by increasing or decreasing the flow rate in the temperature control valve 13 will be described.

FIG. 3 is a schematic diagram showing a schematic configuration of the exhaust heat recovery system in this embodiment. In FIG. 3, the same functional configurations as those in FIG. 1 are designated by the same reference numerals, and the description thereof will be omitted. In FIG. 3, the difference from FIG. 1 is that a three-way solenoid valve 16 is provided upstream and downstream of the heat exchanger 32 for recovering exhaust heat from the discharge stage, and a bypass pipe 15 is provided.

In FIG. 3, a three-way electromagnetic valve 16 is provided upstream and downstream of the heat exchanger 32 for recovering exhaust heat from the discharge stage, and when the temperature cannot be adjusted by increasing or decreasing the flow rate in the temperature control valve 13, the exhaust heat recovery water line Is changed from the exhaust heat recovery liquid pipe 7 to the bypass pipe 15. As a result, the recovery temperature can be adjusted by performing heat exchange only with the heat exchanger 31 for recovering the waste heat of the intermediate stage. Along with this, the valve adjustment range of the temperature control valve 13 can be expanded.

FIG. 4 is a control processing flow performed by the temperature controller 12 that controls the temperature control valve 13 in order to keep the temperature of the recovered water constant at 90 ° C. in the waste heat recovery system 100 in this embodiment. In FIG. 4, the steps with the same reference numerals as those in FIG. 2 are the same processes, and the description thereof will be omitted. In FIG. 4, the difference from FIG. 2 is the bypass control part when the temperature control valve 13 is fully open or fully closed.

Hereinafter, each processing step of bypass control when the temperature control valve 13 in FIG. 4 is fully open or fully closed will be described.
S301: When the recovered water temperature exceeds 90 ° C. and the temperature control valve 13 is fully opened, if heat is recovered by two heat exchangers for exhaust heat recovery (two heat exchanger lines), the process proceeds to S302. The valve direction of the three-way electromagnetic valve 16 is changed. If it is not a line of two heat exchangers, proceed to S207.
S302: By flowing the exhaust heat recovery water through the bypass pipe 15, heat exchange is narrowed down to one of the heat exchangers 31 for intermediate stage exhaust heat recovery (one heat exchanger line), and the recovery water temperature is lowered.
S303: When the recovered water temperature is less than 90 ° C. and the temperature control valve 13 is fully closed, if heat is recovered by one heat exchanger for exhaust heat recovery (one heat exchanger line), the process proceeds to S304. The valve direction of the three-way electromagnetic valve 16 is changed. If it is not one heat exchanger line, proceed to S207.
S304: By flowing exhaust heat recovery water through the exhaust heat recovery liquid pipe 7, two heat exchangers (heat exchanger 31) for intermediate stage exhaust heat recovery and heat exchanger 32 for discharge stage exhaust heat recovery (heat) are exchanged. Use a line of two exchangers) to raise the temperature of the recovered water.

As described above, according to the present embodiment, even when the flow rate cannot be completely controlled by the valve opening / closing angle of the temperature control valve, the recovery water temperature can be adjusted by changing the hot water recovery line.

Although the examples have been described above, the present invention is not limited to the above-mentioned examples, and various modifications are included. For example, the above-described embodiment has been described in detail in order to explain the present invention in an easy-to-understand manner, and is not necessarily limited to those having all the described configurations. For example, in the embodiment, the exhaust heat recovery liquid pipe 7 passes through the heat exchanger 31 for intermediate stage exhaust heat recovery and the heat exchanger 32 for discharge stage exhaust heat recovery from the exhaust heat recovery liquid inflow port 71. It is configured to be connected to the exhaust heat recovery liquid outlet 72, but is not limited thereto. That is, a plurality of exhaust heat recovery liquid pipes 7 are provided corresponding to a plurality of heat exchangers for exhaust heat recovery, and each of the plurality of exhaust heat recovery liquid pipes is separately provided as an independent path in the housing. It may be provided. Here, the plurality of heat exchangers for exhaust heat recovery may be an intermediate stage exhaust heat recovery heat exchanger 31 and a discharge stage exhaust heat recovery heat exchanger 32. Alternatively, a plurality of heat exchangers for recovering exhaust heat are connected in series with a heat exchanger 31 for recovering waste heat in the intermediate stage (or a heat exchanger 32 for recovering exhaust heat in the discharge stage). It may be configured as. According to such a configuration, exhaust heat recovery water having a plurality of different temperatures can be obtained and used from each of the plurality of exhaust heat recovery liquid pipes. This makes it possible to support a plurality of facilities and the like having different temperatures of the required exhaust heat recovery water.

Further, in the embodiment, the coolant pipe 8 branches from the coolant inflow port 80 into the first coolant pipe 81, the second coolant pipe 82, and the third coolant pipe 83, and then merges with each other. It is configured to connect to the coolant outlet 84, but is not limited thereto. For example, a plurality of coolant pipes 8 may be provided corresponding to a plurality of cooling heat exchangers, and each of the plurality of coolant pipes may be separately provided in the housing as an independent path. Here, the plurality of cooling heat exchangers may be an intercooler 51 and an aftercooler 52. Alternatively, the plurality of cooling heat exchangers may be configured as a plurality of heat exchangers in which the intercooler 51 (or the aftercooler 52) is connected in series.

Further, in the embodiment, the temperature sensor 11, the temperature controller 12, and the temperature control valve 13 are used to control the temperature of the exhaust heat recovery water so as to keep it constant, but the temperature is not limited to this and is exhausted. It suffices if the flow rate can be controlled by the temperature of the heat recovery water. For example, a self-powered automatic temperature control valve that does not require auxiliary power such as air pressure, water pressure, hydraulic pressure, and electricity without using a temperature sensor 11 or a temperature controller 12. May be.

Further, in the embodiment, the air compressor 1 is specifically applicable to the screw compressor, but the present invention is not limited thereto. That is, in the embodiment, the screw rotor is used for the compressor main bodies 21 and 22, but the present invention is not limited to this, and the turbo type such as the centrifugal type and the axial flow type, the scroll type, the reciprocating type, and the claw type are used. Various types of positive displacement compression means such as, etc. can be used. Further, in the embodiment, a twin screw type rotor is used, but a single or triple screw type rotor may be used.

Further, in the embodiment, the number of stages of the compressor main bodies 21 and 22 is two, but the number of stages is not limited to this, and the number of stages may be single or three or more.

Further, in the embodiment, the air compressor 1 is an oil-free screw compressor, but is not limited to this, and is a liquid supply type air compressor that injects oil or water into the compression operating chamber. May be good. Further, although the gas to be compressed has been described as air, the present invention is not limited to this, and nitrogen or the like may be used.

Further, in the embodiment, the temperature of the exhaust heat recovery water sent from the exhaust heat utilization side is 70 to 90 ° C., but is not limited to this, and is, for example, a predetermined temperature range of about 35 ° C. or higher. You may.

Further, in the embodiment, the cooling water whose temperature has risen is configured to be cooled by exchanging heat with the atmosphere in the cooling tower, but the present invention is not limited to this, and the cooling water whose temperature has risen is not limited to this. It is also possible to recover and use the heat.

Further, it is possible to replace a part of the configuration of one embodiment with the configuration of another embodiment, and it is also possible to add the configuration of another embodiment to the configuration of one embodiment. Further, it is possible to add / delete / replace a part of the configuration of each embodiment with another configuration.

1: Air compressor 2: Exhaust heat recovery machine 4: Blow-out piping, 6: Air piping, 7: Exhaust heat recovery liquid piping, 8: Coolant piping, 9: Oil cooler, 10: Check valve, 11 : Temperature sensor, 12: Temperature controller, 13: Temperature control valve, 14: Circulation pump, 15: Bypass piping, 16: 3-way electromagnetic valve, 21: 1st stage compressor body, 22: 2nd stage Compressor body, 31: heat exchanger for intermediate stage exhaust heat recovery, 32: heat exchanger for discharge stage exhaust heat recovery, 51: heat exchanger for cooling (intercooler), 52: heat exchange for cooling Vessel (after cooler), 81: 1st coolant piping, 82: 2nd coolant piping, 83: 3rd coolant piping, 100: exhaust heat recovery system

Claims (10)

Exhaust heat that flows through a gas compressor that has a compressor body that compresses gas and outputs compressed gas, a heat exchanger for exhaust heat recovery, and exhaust heat recovery water that exchanges heat with the compressed gas in the heat exchanger. An exhaust heat recovery system having an exhaust heat recovery machine provided with a recovery liquid pipe.
The compressor body and the heat exchanger for recovering exhaust heat are connected by a gas pipe through which the gas to be compressed flows.
The exhaust heat recovery machine includes a temperature sensor installed downstream of the heat exchanger for exhaust heat recovery in the exhaust heat recovery liquid pipe, a temperature control valve, and the exhaust heat recovery water measured by the temperature sensor. An exhaust heat recovery system comprising a temperature controller that controls an opening / closing angle of the temperature control valve according to a temperature and a set recovery water temperature. The waste heat recovery system according to claim 1.
The gas compressor is an exhaust heat recovery system characterized by having a check valve and a blow-off pipe that are fully closed by unloading operation downstream of the heat exchanger for exhaust heat recovery in the gas pipe. The waste heat recovery system according to claim 1.
The compressor body is a first-stage compressor body arranged on the upstream side of the gas flow and a second stage compressor body arranged on the downstream side of the gas flow with respect to the first-stage compressor body. Consists of a stage compressor body
The heat exchanger for exhaust heat recovery includes an intermediate stage heat exchanger for exhaust heat recovery arranged between the compressor main body of the first stage and the compressor main body of the second stage, and the first stage. It consists of a heat exchanger for exhaust heat recovery in the discharge stage, which is located on the downstream side of the two-stage compressor body.
The exhaust heat recovery system is characterized in that the temperature sensor is installed downstream of the heat exchanger for recovering the intermediate stage exhaust heat. The waste heat recovery system according to claim 3.
The gas compressor is a waste heat recovery system characterized by having a check valve and a blow-off pipe that are fully closed by unloading operation downstream of the heat exchanger for recovering exhaust heat from the discharge stage in the gas pipe. .. The waste heat recovery system according to claim 1.
The exhaust heat recovery system is characterized in that the compressor body is an oil-free screw compressor. The waste heat recovery system according to claim 3.
The exhaust heat recovery machine is an exhaust heat recovery system characterized in that a three-way solenoid valve is provided upstream and downstream of the heat exchanger for exhaust heat recovery in the discharge stage, and a bypass pipe is provided. The waste heat recovery system according to claim 6.
The gas compressor is a waste heat recovery system characterized by having a check valve and a blow-off pipe that are fully closed by unloading operation downstream of the heat exchanger for recovering exhaust heat from the discharge stage in the gas pipe. .. A gas compressor used in an exhaust heat recovery system having a heat exchanger that recovers the exhaust heat generated when the gas is compressed.
It has a compressor body that compresses gas, and the compressor body and the heat exchanger are connected by a gas pipe through which the gas to be compressed flows.
A gas compressor characterized by having a check valve and a blow-off pipe that are fully closed by unloading operation downstream of the heat exchanger in the gas pipe. The gas compressor according to claim 8.
The compressor body is a first-stage compressor body arranged on the upstream side of the gas flow and a second stage compressor body arranged on the downstream side of the gas flow with respect to the first-stage compressor body. Consists of a stage compressor body
The heat exchanger includes an intermediate stage exhaust heat recovery heat exchanger arranged between the first stage compressor main body and the second stage compressor main body, and the second stage compressor. It consists of a heat exchanger for exhaust heat recovery at the discharge stage located on the downstream side of the main body.
A gas compressor characterized by having a check valve and a blow-off pipe that are fully closed by unloading operation downstream of the heat exchanger for recovering exhaust heat from the discharge stage in the gas pipe. The gas compressor according to claim 8.
The compressor body is a gas compressor characterized by being an oil-free screw compressor.

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