Air compressor

Abstract

The present invention provides an air compressor which is capable of recovering carbon dioxide while suppressing power consumption.　The air compressor comprises: compressor main bodies 3A, 3B for compressing air; an air release valve 11A which is provided in a branch pipe 10A branched from a discharge pipe 4A of the compressor main body 3A; a carbon dioxide recovery device 20A which is disposed on the downstream side of the air release valve 11A and recovers carbon dioxide in the compressed air; an air release valve 11B which is provided in a branch pipe 10B branched from a discharge pipe 4B of the compressor main body 3B; and a carbon dioxide recovery device 20B which is disposed on the downstream side of the air release valve 11B and recovers carbon dioxide in the compressed air.

Description

Air compressor

[0001] The present invention relates to an air compressor.

[0002] In recent years, as one of the measures against global warming, it has been proposed to provide an air compressor with a carbon dioxide recovery device for recovering carbon dioxide in the air (see Patent Document 1, etc.). In Patent Document 1, the carbon dioxide recovery device is provided in front of the air compressor, and air is caused to flow through the carbon dioxide recovery device by utilizing the suction force of the air compressor.

[0003] Japanese Patent Application Laid-Open No. 2023-090003

[0004] However, in Patent Document 1, since the carbon dioxide recovery device is provided in front of the air compressor, the load on the air compressor increases and the power consumption increases. One of the problems of the present invention is to recover carbon dioxide while suppressing the power consumption of the air compressor.

[0005] In order to solve the above problems, the configuration described in the claims is applied. The present invention includes a plurality of means for solving the above problems. For example, in an air compressor including a compressor body that compresses air and a valve provided in a branch pipe branched from a discharge pipe of the compressor body, a carbon dioxide recovery device that is disposed upstream or downstream of the valve in the branch pipe and recovers carbon dioxide in compressed air is provided.

[0006] According to the present invention, carbon dioxide can be recovered while suppressing the power consumption of the air compressor.

[0007] In addition, problems, configurations, and effects other than those described above will be clarified by the following description.

[0008] It is a schematic diagram showing the configuration of an air compressor in an embodiment of the present invention.

[0009] An embodiment of the present invention will be described with reference to FIG. 1. FIG. 1 is a schematic diagram showing the configuration of the air compressor in the present embodiment. The air compressor of the present embodiment is configured as a unit in which devices described later are housed in a housing.

[0010] The air compressor comprises an electric motor 1, a low-pressure stage compressor body 3A driven by the electric motor 1 that draws in air through an air filter 2 and compresses it, a cooler 5A (intercooler) that cools the compressed air discharged from the compressor body 3A through a discharge pipe 4A, a drain separator 6 that separates drain (condensed water) from the compressed air cooled by the cooler 5A, a high-pressure stage compressor body 3B driven by the electric motor 1 that further compresses the compressed air from the drain separator 6, and a cooler 5B (aftercooler) that cools the compressed air discharged from the compressor body 3B through a discharge pipe 4B and a check valve 7.

[0011] The air compressor further comprises a pressure sensor 8A provided on the discharge pipe 4A of the compressor body 3A (specifically, downstream of the drain separator 6), a pressure sensor 8B provided on the discharge pipe 4B of the compressor body 3B (specifically, downstream of the cooler 5B), a suction throttle valve 9 provided on the suction side of the compressor body 3A, an air release valve 11A provided on the branch pipe 10A branched from the discharge pipe 4A of the compressor body 3A (specifically, upstream of the cooler 5A), an air release valve 11B provided on the branch pipe 10B branched from the discharge pipe 4B of the compressor body 3B (specifically, upstream of the check valve 7), and a control device 12.

[0012] The control device 12 includes a processor that executes processing according to a program and a memory that stores the program and data. The control device 12 controls the suction throttle valve 9 and the air release valves 11A and 11B according to the pressure on the downstream side of the compressor body 3A detected by the pressure sensor 8A and the pressure on the downstream side of the compressor body 3B detected by the pressure sensor 8B.

[0013] More specifically, when the pressure detected by the pressure sensor 8A is less than a first threshold and the pressure detected by the pressure sensor 8B is less than a second threshold (provided the second threshold is greater than the first threshold), the control device 12 controls the suction throttle valve 9 to be fully open and the air release valves 11A and 11B to be fully closed. This causes the compressor bodies 3A and 3B to operate at full load.

[0014] When the pressure detected by the pressure sensor 8A exceeds a first threshold, the control device 12 decreases the opening of the suction throttle valve 9 and increases the opening of the air release valve 11A according to the difference between the pressure detected by the pressure sensor 8A and the first threshold. That is, it switches the air release valve 11A to the open state and releases compressed air from the discharge side of the compressor body 3A. This switches the compressor body 3A from full load operation to partial load operation.

[0015] When the pressure detected by the pressure sensor 8B exceeds the second threshold, the control device 12 increases the opening of the air release valve 11B according to the difference between the pressure detected by the pressure sensor 8B and the second threshold. That is, it switches the air release valve 11B to the open state and releases compressed air from the discharge side of the compressor body 3B. This switches the compressor body 3B from full load operation to partial load operation.

[0016] The air compressor further includes a safety valve 13A provided on a branch pipe 10C that branches off from the discharge pipe 4A of the compressor body 3A (specifically, upstream of the cooler 5A) (however, it may be branched via the branch pipe 10A as shown in the figure, or it may be branched directly), and a safety valve 13B provided on a branch pipe 10D that branches off from the discharge pipe 4B of the compressor body 3B (specifically, upstream of the check valve 7) (however, it may be branched via the branch pipe 10B as shown in the figure, or it may be branched directly).

[0017] The safety valves 13A and 13B are supplied with power in the same way as the electric motor 1 and other electrical equipment, and they operate when power is not supplied, switching from the closed state to the open state. This releases compressed air from the discharge side of the compressor bodies 3A and 3B, enhancing safety in the event of a power outage.

[0018] The air compressor further includes a relief valve 14 provided in a branch pipe 10E that branches off from the discharge pipe 4B of the compressor body 3B (specifically, downstream of the cooler 5B). The relief valve 14 operates and switches from a closed state to an open state when the inlet pressure is equal to or greater than a third threshold (provided that the third threshold > the second threshold). This releases compressed air from the discharge side of the compressor body 3B, enhancing safety in the event of an abnormality.

[0019] The compressor body 3A comprises, for example, a pair of screw rotors that rotate in a meshing manner with each other, and a casing that houses them. As the screw rotors rotate, the working chambers formed in the tooth grooves of the screw rotors move and their volume changes. This allows for the intake and compression of air, and the discharge of compressed air. The compressor body 3B has substantially the same configuration as the compressor body 3A.

[0020] Gear 15A is connected to one screw rotor of compressor body 3A, gear 15B is connected to one screw rotor of compressor body 3B, and gear 15C is connected to the rotating shaft of electric motor 1, with gear 15C meshing with gears 15A and 15B. The rotational force of electric motor 1 is transmitted via gears 15A, 15B and 15C to drive compressor bodies 3A and 3B.

[0021] The gearbox 16 houses the gears 15A, 15B, and 15C and also stores lubricating oil. The air inside the gearbox 16 is discharged through the piping 17, the oil mist recovery device 18, and the ejector 19, so that the pressure inside the gearbox 16 becomes lower than the pressure inside the operating chambers of the compressor bodies 3A and 3B. This prevents the lubricating oil inside the gearbox 16 from entering the operating chambers of the compressor bodies 3A and 3B. The ejector 19 uses, for example, a portion of the compressed air to suck and discharge the air inside the gearbox 16. The oil mist recovery device 18 has, for example, a filter that separates oil mist from the air and returns the separated oil mist to the gearbox 16.

[0022] A feature of this embodiment is that the air compressor further comprises a carbon dioxide recovery device 20A located downstream of the air release valve 11A, a carbon dioxide recovery device 20B located downstream of the air release valve 11B, a carbon dioxide recovery device 20C located downstream of the safety valve 13A, a carbon dioxide recovery device 20D located downstream of the safety valve 13B, and a carbon dioxide recovery device 20E located upstream of the relief valve 14 in the branch piping 10E.

[0023] The carbon dioxide recovery devices 20A, 20B, 20C, 20D, or 20E are composed of, for example, an adsorbent that adsorbs carbon dioxide from compressed air and a container that houses the adsorbent. The adsorbent is composed of, for example, a carrier carrying an amine-based absorbent, a calcium compound, or a magnesium compound, and chemically adsorbs carbon dioxide from the air. Alternatively, the adsorbent is composed of, for example, zeolite, activated carbon, or silica, and physically adsorbs carbon dioxide from the air. If the adsorbent is configured to chemically adsorb carbon dioxide from the air, it is possible to increase the amount of carbon dioxide adsorbed by utilizing the heat of the compressed air.

[0024] If the compressor bodies 3A and 3B are operating at full load and no power outage or malfunction occurs, the air release valves 11A and 11B, safety valves 13A and 13B, and relief valve 14 are closed, and compressed air does not flow to the carbon dioxide recovery devices 20A to 20E. On the other hand, if the air release valves 11A and 11B are switched from closed to open in order to switch from full load operation to partial load operation of the compressor bodies 3A and 3B, compressed air flows to the carbon dioxide recovery devices 20A and 20B by utilizing the flow of compressed air released through the air release valves 11A and 11B. Also, if the safety valves 13A and 13B are switched from closed to open in the event of a power outage, compressed air flows to the carbon dioxide recovery devices 20C and 20D by utilizing the flow of compressed air released through the safety valves 13A and 13B. Furthermore, when the relief valve 14 is switched from the closed state to the open state in the event of an abnormality, compressed air flows to the carbon dioxide recovery device 20E using the flow of compressed air released through the relief valve 14. Therefore, unlike, for example, when the carbon dioxide recovery device is installed in the discharge piping, the load on the air compressor does not increase. Thus, carbon dioxide can be recovered while keeping the power consumption of the air compressor low.

[0025] A feature of this embodiment is that the air compressor further includes a carbon dioxide recovery device 21 located upstream of the ejector 19. The carbon dioxide recovery device 21 is composed of, for example, an adsorbent that adsorbs carbon dioxide from compressed air and a container that houses the adsorbent. Compressed air flows to the carbon dioxide recovery device 21 using the air flow released through the ejector 19. Therefore, the load on the air compressor does not increase. Consequently, carbon dioxide can be recovered while keeping the power consumption of the air compressor low.

[0026] In the above embodiment, the carbon dioxide recovery device 20A was described as being located downstream of the air release valve 11A, and the carbon dioxide recovery device 20C was described as being located downstream of the safety valve 13A, but the invention is not limited to this. The carbon dioxide recovery device 20A may be located upstream of the air release valve 11A in the branch pipe 10A. The carbon dioxide recovery device 20C may be located upstream of the safety valve 13A in the branch pipe 10C. Alternatively, the carbon dioxide recovery devices may be standardized and located upstream of the branch point of the branch pipe 10C in the branch pipe 10A.

[0027] Furthermore, although the above embodiment described an example in which the carbon dioxide recovery device 20B is located downstream of the air release valve 11B and the carbon dioxide recovery device 20D is located downstream of the safety valve 13B, the invention is not limited to this. The carbon dioxide recovery device 20B may be located upstream of the air release valve 11B in the branch pipe 10B. The carbon dioxide recovery device 20D may be located upstream of the safety valve 13B in the branch pipe 10D. Alternatively, the carbon dioxide recovery devices may be standardized and located upstream of the branch point of the branch pipe 10D in the branch pipe 10B.

[0028] Furthermore, although the above embodiment described an example in which the carbon dioxide recovery device 20E is located upstream of the relief valve 14 in the branch piping 10E, it is not limited to this and may be located downstream of the relief valve 14.

[0029] Furthermore, although the above embodiment described an example in which the carbon dioxide recovery device 21 is located upstream of the ejector 19, it is not limited to this and may be located downstream of the ejector 19.

[0030] Furthermore, although the above embodiment described an example in which the air compressor is equipped with carbon dioxide recovery devices 20A to 20E and carbon dioxide recovery device 21, it is not limited to this. The air compressor does not need to be equipped with carbon dioxide recovery device 21. Also, the air compressor only needs to be equipped with at least one of the carbon dioxide recovery devices 20A to 20E.

[0031] In the above description, the present invention has been explained using an air compressor equipped with two compressor bodies 3A and 3B as an example, but it is not limited to this, and the present invention may also be applied to an air compressor equipped with only one compressor body.

[0032] 1...Electric motor, 3A, 3B...Compressor body, 4A, 4B...Discharge piping, 10A-10E...Branch piping, 11A, 11B...Air release valve, 12...Control device, 13A, 13B...Safety valve, 14...Relief valve, 15A-15C...Gear, 16...Gearbox, 19...Ejector, 20A-20E...Carbon dioxide recovery device, 21...Carbon dioxide recovery device

Claims

1. An air compressor comprising a compressor body for compressing air and a valve provided in a branch pipe branched from the discharge pipe of the compressor body, characterized in that it is equipped with a carbon dioxide recovery device disposed upstream or downstream of the valve in the branch pipe for recovering carbon dioxide from the compressed air.

2. An air compressor according to claim 1, wherein the valve is a vent valve whose opening degree is controlled by a control device in accordance with the pressure downstream of the compressor body.

3. An air compressor according to claim 1, wherein the valve is a safety valve that operates when power is not supplied and switches from a closed state to an open state.

4. An air compressor according to claim 1, wherein the valve is a relief valve that operates and switches from a closed state to an open state when the inlet pressure is above a predetermined value.

5. An air compressor according to claim 1, characterized by comprising: a gearbox housing a plurality of gears that transmit the rotational force of an electric motor to the compressor body; an ejector that sucks in and discharges air from the gearbox; and a carbon dioxide recovery device disposed upstream or downstream of the ejector for recovering carbon dioxide from the air.

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