JP-7857109-B2 - Reciprocating compressor

JP7857109B2JP 7857109 B2JP7857109 B2JP 7857109B2JP-7857109-B2

Inventors

和田大祐
兼井直史

Assignees

株式会社神戸製鋼所

Dates

Publication Date: 20260512
Application Date: 20220209

Claims (6)

A reciprocating compressor for compressing hydrogen gas, A low-pressure stage compression section for compressing hydrogen gas has a low-pressure stage piston, a low-pressure stage cylinder section housing the low-pressure stage piston, and a group of piston rings attached to the low-pressure stage piston. A high-pressure stage compression section comprises a high-pressure stage piston connected to the low-pressure stage piston, a high-pressure stage cylinder section housing the high-pressure stage piston and connected to the low-pressure stage cylinder section, and a group of piston rings attached to the high-pressure stage piston, and compresses the hydrogen gas after it has been compressed in the low-pressure stage compression section. A drive unit that drives the high-pressure stage compression unit and the low-pressure stage compression unit, A discharge mechanism capable of discharging hydrogen gas from the suction side passage through which the hydrogen gas drawn into the low-pressure compression section flows, A pressure sensor for detecting the pressure of hydrogen gas drawn into the low-pressure compression section, The system includes a discharge control unit that controls the discharge mechanism to discharge hydrogen gas from the suction side passage when the pressure of the hydrogen gas detected by the pressure sensor is higher than a preset value, The aforementioned setting value is the normal pressure value of hydrogen gas drawn into the low-pressure stage compression section when the suction valve of the low-pressure stage compression section is opened by the differential pressure between the pressure in the suction-side passage and the pressure in the compression chamber of the low-pressure stage compression section, in a reciprocating compressor.
A reciprocating compressor for compressing hydrogen gas, A low-pressure stage compression section for compressing hydrogen gas has a low-pressure stage piston, a low-pressure stage cylinder section housing the low-pressure stage piston, and a group of piston rings attached to the low-pressure stage piston. A high-pressure stage compression section comprises a high-pressure stage piston connected to the low-pressure stage piston, a high-pressure stage cylinder section housing the high-pressure stage piston and connected to the low-pressure stage cylinder section, and a group of piston rings attached to the high-pressure stage piston, and compresses the hydrogen gas after it has been compressed in the low-pressure stage compression section. A drive unit that drives the high-pressure stage compression unit and the low-pressure stage compression unit, A discharge mechanism capable of discharging hydrogen gas from the suction side passage through which the hydrogen gas drawn into the low-pressure compression section flows, A pressure sensor for detecting the pressure of hydrogen gas drawn into the low-pressure stage compression section or the pressure of hydrogen gas discharged from the low-pressure stage compression section, The system includes a discharge control unit that controls the discharge mechanism to discharge hydrogen gas from the suction side passage when the pressure of the hydrogen gas detected by the pressure sensor is higher than a preset value, The drive unit has a rotatable motor, The aforementioned reciprocating compressor, The drive unit includes an inverter capable of adjusting the rotational speed of the motor, A reciprocating compressor further comprising: a rotation speed control unit that controls the inverter to increase the rotation speed of the motor in order to compensate for the amount of hydrogen gas discharged from the suction side passage when hydrogen gas is discharged from the suction side passage.
The pressure sensor is located in the suction side flow path, The discharge mechanism comprises a gas discharge passage connected to the suction side passage, and a discharge valve located in the gas discharge passage and capable of adjusting the valve opening. The reciprocating compressor further includes an auxiliary pressure sensor located downstream of the discharge valve in the gas discharge passage. The reciprocating compressor according to claim 2, wherein the rotational speed control unit is configured to increase the rotational speed of the motor to compensate for an amount corresponding to the discharge flow rate of hydrogen gas derived based on the pressure detected by the pressure sensor, the pressure detected by the auxiliary pressure sensor, and the flow rate characteristics of the discharge valve.
The discharge mechanism comprises a gas discharge passage connected to the suction side passage, an on-off valve located in the gas discharge passage, and an orifice located downstream of the on-off valve in the gas discharge passage. The reciprocating compressor further includes an auxiliary pressure sensor located downstream of the orifice in the gas discharge passage. The reciprocating compressor according to claim 2, wherein the rotational speed control unit is configured to increase the rotational speed of the motor in order to supplement the hydrogen gas discharge flow rate derived based on the pressure detected by the pressure sensor, the pressure detected by the auxiliary pressure sensor, and the throttling ratio of the gas discharge passage by the orifice.
The hydrogen gas discharged from the aforementioned reciprocating compressor is supplied to an accumulator consisting of a tank. A demand-side pressure sensor located in the accumulator, or located in the demand-side connection channel connecting the reciprocating compressor and the accumulator to each other, A demand-side temperature sensor located in the accumulator or the demand-side connection channel, An estimation unit that estimates the amount of density change per unit time of hydrogen gas stored in the accumulator based on the pressure detected by the demand-side pressure sensor, the temperature detected by the demand-side temperature sensor, and the tank capacity of the accumulator. Furthermore, The reciprocating compressor according to claim 2, wherein the rotational speed control unit is configured to increase the rotational speed of the motor by an amount equivalent to the difference between the amount of change in hydrogen gas density per unit time accumulated in the accumulator when there is no leakage of hydrogen gas from the high-pressure stage compression unit to the low-pressure stage compression unit and the amount of change in hydrogen gas density per unit time estimated by the estimation unit.
A reciprocating compressor for compressing hydrogen gas, A low-pressure stage compression section for compressing hydrogen gas has a low-pressure stage piston, a low-pressure stage cylinder section housing the low-pressure stage piston, and a group of piston rings attached to the low-pressure stage piston. An intermediate compression section compresses the hydrogen gas discharged from the low-pressure compression section, A high-pressure stage compression section comprises a high-pressure stage piston connected to the low-pressure stage piston, a high-pressure stage cylinder section housing the high-pressure stage piston and connected to the low-pressure stage cylinder section, and a group of piston rings attached to the high-pressure stage piston, and compresses the hydrogen gas discharged from the intermediate stage compression section. A drive unit that drives the low-pressure stage compression section, the intermediate stage compression section, and the high-pressure stage compression section, A discharge mechanism capable of discharging hydrogen gas from the suction side passage through which the hydrogen gas drawn into the low-pressure compression section flows, A pressure sensor for detecting the pressure of hydrogen gas drawn into the low-pressure compression section, The system includes a discharge control unit that controls the discharge mechanism to discharge hydrogen gas from the suction side passage when the pressure of the hydrogen gas detected by the pressure sensor is higher than a preset value, A reciprocating compressor in which the set value is the normal pressure value of hydrogen gas drawn into the low-pressure stage compression section when the suction valve of the low-pressure stage compression section is opened by the differential pressure between the pressure of hydrogen gas drawn into the low-pressure stage compression section and the pressure in the compression chamber of the low-pressure stage compression section.

Description

This invention relates to a reciprocating compressor. Conventionally, as disclosed in Patent Document 1 below, a reciprocating compressor for compressing hydrogen gas, equipped with multiple compression stages, is known. The compressor disclosed in Patent Document 1 has five compression stages, each having a piston fitted with a piston ring and a cylinder housing the piston. The first to third compression stages are connected to each other, forming a so-called tandem type, and the fourth and fifth compression stages are also connected to each other, forming a tandem type. The pistons of the first to fifth compression stages are driven by a common drive source. In this configuration, if gas leaks from the second-stage compression chamber due to, for example, wear of the piston rings in the second-stage compression section, the discharge pressure of the first-stage compression section (the suction pressure of the second compression section) may increase. This is because the gas leaking from the compression chamber in the second-stage compression section flows into the compression chamber in the first-stage compression section. Japanese Patent Publication No. 2018-17145 This diagram schematically shows the configuration of a reciprocating compressor according to the first embodiment.This figure schematically shows the configuration of a reciprocating compressor according to a modified example of the first embodiment.This diagram schematically shows the configuration of a reciprocating compressor according to the second embodiment.This diagram schematically shows the flow rate characteristic data of the discharge valve stored in the controller.This figure partially and schematically shows a reciprocating compressor according to a modified example of the second embodiment.This diagram schematically shows the flow rate characteristic data of the orifice stored in the controller.This figure partially and schematically shows a reciprocating compressor according to the third embodiment.This diagram schematically shows the relationship between time and gas density as stored in the controller.This diagram schematically shows the configuration of a reciprocating compressor according to the fourth embodiment.This diagram schematically shows the configuration of a reciprocating compressor according to another embodiment.This diagram schematically shows the configuration of a reciprocating compressor according to another embodiment. The embodiments for carrying out the present invention will be described in detail below with reference to the drawings. (First Embodiment) As shown in Figure 1, the reciprocating compressor 10 according to the first embodiment is a compressor for compressing hydrogen gas and is configured as a multi-stage compressor equipped with multiple (five stages in the illustrated example) compression sections 11 to 15. This reciprocating compressor 10 may be installed, for example, at a hydrogen station for filling tanks of fuel cell vehicles and the like that which utilize high-pressure hydrogen gas. The reciprocating compressor 10 comprises a first-stage compression section 11, a second-stage compression section 12, a third-stage compression section 13, a fourth-stage compression section 14, a fifth-stage compression section 15, and a drive section 20 that drives these compression sections 11 to 15. The hydrogen gas compressed in the first-stage compression section 11 is introduced into the second-stage compression section 12 and further compressed. This hydrogen gas is then sequentially compressed by the third to fifth-stage compression sections 13 to 15. Each of the compression sections 11 to 15 has a piston 23 fitted with a piston ring group 22 and a cylinder section 24 housing the piston 23. The space on the tip side of the piston 23 within the cylinder section 24 functions as a compression chamber 25, and is configured as a reciprocating compression mechanism. Each of the cylinder sections 24 of the compression sections 11 to 15 is provided with an intake valve 27 and a discharge valve 28 at a position facing the corresponding compression chamber 25. In the first-stage compression section 11, an intake pipe 30 is connected to the intake valve 27, and one end of a first connecting pipe 31 is connected to the discharge valve 28. Therefore, hydrogen gas is drawn into the compression chamber 25 of the first-stage compression section 11 through the intake pipe 30. The other end of the first connecting pipe 31 is connected to the intake valve 27 of the second-stage compression section 12. Therefore, the hydrogen gas compressed in the first-stage compression section 11 is drawn into the compression chamber 25 of the second-stage compression section 12. One end of a second connecting pipe 32 is connected to the discharge valve 28 of the second-stage compression section 12, and the other end of the second connecting pipe 32 is connected to the intake valve 27 of the third-stage compression section 13. Th