Energy-saving system and method for chiller controlled by frequency converter

Abstract

The present invention relates to the field of cold water system regulation, and provides a frequency converter controlled chiller energy-saving system and method, including: an air supply unit, a hydrogen compressor, a first cold water unit, a second cold water unit, a heat exchanger, a hydrogenator, a venting unit and a hydrogenation vehicle; the air supply unit is connected to the hydrogen compressor, the hydrogen compressor is connected to the first cold water unit, the hydrogen compressor is connected to the venting unit, the hydrogen compressor is connected to the heat exchanger, the heat exchanger is connected to the second cold water unit, the heat exchanger is connected to the hydrogenator, the hydrogenator is connected to the hydrogenation vehicle, and the hydrogenator is connected to the venting unit. The present invention adjusts the power of the chiller according to the water temperature difference between the water inlet and the water outlet of the chiller, and the load range of the guide vane, so that the start-up and operation of the chiller have obvious energy-saving effects; the frequency converter is used to drive the chiller, which improves the operating performance of the chiller, prevents surge, and enhances the flexibility of operation regulation.

Description

Technical Field

[0001] The present invention relates to the field of chiller system regulation, and in particular to an energy-saving system and method for a chiller controlled by a frequency converter. Background Art

[0002] At present, most hydrogen refueling stations use air-cooled ethylene glycol chillers specially used for H2 cooling systems. The chillers use 380V50HZ AC three-phase electricity as the power source. Due to the actual demand for the cooling capacity of the chillers, the power of the chillers generally used in hydrogen refueling stations is between 15KW and 260KW. In production and use, the chillers are operated with the start and stop of the hydrogen booster compressor and the hydrogenator. During this period, the chillers are operated at a fixed frequency of 50HZ. When the outlet water temperature of the chillers reaches the required value, the chillers are still operated at a fixed frequency of 50HZ. The long-term operation of high-power power-consuming equipment in this way consumes a lot of electricity, which is also a waste of energy.

[0003] The above contents are only used to assist in understanding the technical solution of the present invention and do not constitute an admission that the above contents are prior art. Summary of the invention

[0004] The main purpose of the present invention is to solve the technical problem of excessive power consumption of air-cooled ethylene glycol chilled water units dedicated to H2 cooling systems in the prior art.

[0005] To achieve the above object, the present invention provides a frequency converter-controlled chiller energy-saving system, comprising: an air supply unit, a hydrogen compressor, a first chiller unit, a second chiller unit, a heat exchanger, a hydrogenator, a venting unit and a hydrogenation vehicle;

[0006] The air supply unit is connected to the hydrogen compressor, the hydrogen compressor is connected to the first cold water unit, the discharge port of the hydrogen compressor is connected to the first inlet of the discharge unit, the hydrogen outlet of the hydrogen compressor is connected to the air inlet of the heat exchanger, the heat exchanger is connected to the second cold water unit, the air outlet of the heat exchanger is connected to the air inlet of the hydrogenator, the filling port of the hydrogenator is connected to the hydrogenation vehicle, and the discharge port of the hydrogenator is connected to the second inlet of the discharge unit.

[0007] Preferably, the gas supply unit is connected to the hydrogen compressor in the following manner:

[0008] The nitrogen outlet of the gas supply unit is connected to one end of the first gas valve, and the other end of the first gas valve is connected to the nitrogen inlet of the hydrogen compressor;

[0009] The hydrogen outlet of the gas supply unit is connected to one end of the second gas valve, and the other end of the second gas valve is connected to the hydrogen inlet of the hydrogen compressor.

[0010] Preferably, the first cold water unit comprises: a fourth water valve, a fifth water valve, a first temperature sensor, a second temperature sensor and a first chiller;

[0011] The hydrogen compressor is connected to the first cooling water unit in the following manner:

[0012] The water outlet of the hydrogen compressor is connected to the second temperature sensor and one end of the fifth water valve, and the other end of the fifth water valve is connected to the water inlet of the first chiller;

[0013] The water inlet of the hydrogen compressor is connected to the first temperature sensor and one end of the fourth water valve, and the other end of the fourth water valve is connected to the water outlet of the first chiller.

[0014] Preferably, the first chiller comprises: a first frequency converter, a first chiller compressor, a first cooling fan, a first controller and a first guide vane;

[0015] The first controller is electrically connected to the first temperature sensor, the second temperature sensor, the first inverter and the first guide vane, the inverter is electrically connected to the first cold water compressor, and the first cold water compressor is electrically connected to the first cooling fan.

[0016] Preferably, the second cold water unit comprises: a sixth water valve, a seventh water valve, a third temperature sensor, a fourth temperature sensor and a second cold water unit;

[0017] The hydrogen outlet of the hydrogen compressor is connected to the air inlet of the heat exchanger, and the heat exchanger is connected to the second cold water unit, specifically:

[0018] The hydrogen outlet of the hydrogen compressor is connected to one end of the third gas valve, and the other end of the third gas valve is connected to the air inlet of the heat exchanger;

[0019] The water outlet of the heat exchanger is connected to the fourth temperature sensor and one end of the seventh water valve, and the other end of the seventh water valve is connected to the water inlet of the second chiller;

[0020] The water inlet of the heat exchanger is connected to the third temperature sensor and one end of the sixth water valve, and the other end of the sixth water valve is connected to the water outlet of the second chiller.

[0021] Preferably, the second chiller unit comprises: a second frequency converter, a second chiller compressor, a second cooling fan, a second controller and a second guide vane;

[0022] The second controller is electrically connected to the third temperature sensor, the fourth temperature sensor, the second inverter and the second guide vane, the inverter is electrically connected to the second cold water compressor, and the second cold water compressor is electrically connected to the second cooling fan.

[0023] Preferably, the air outlet of the heat exchanger is connected to the air inlet of the hydrogenator in the following manner:

[0024] The gas outlet of the heat exchanger is connected to one end of the eighth gas valve, and the other end of the eighth gas valve is connected to the gas inlet of the hydrogenator.

[0025] A frequency converter controlled chiller energy saving method is implemented based on the frequency converter controlled chiller energy saving system, comprising the steps of:

[0026] S1: starting the energy-saving system of the chiller controlled by the inverter, setting the load range of the first guide vane in the first chiller, and the load range of the second guide vane in the second chiller;

[0027] S2: The first temperature sensor detects the outlet water temperature T1 of the first chiller in real time, and the second temperature sensor detects the inlet water temperature T2 of the first chiller in real time; the third temperature sensor detects the outlet water temperature T3 of the second chiller in real time, and the fourth temperature sensor detects the inlet water temperature T4 of the second chiller in real time;

[0028] S3: Adjust the working state of the first chiller according to the load range of the first guide vane, the outlet water temperature T1 of the first chiller, and the inlet water temperature T2 of the first chiller; adjust the working state of the second chiller according to the load range of the second guide vane, the outlet water temperature T3 of the second chiller, and the inlet water temperature T4 of the second chiller.

[0029] Preferably, step S3 specifically includes:

[0030] S31: If the load range of the first guide blade is between 70% and 100%, the first guide blade is fully open; if the load range of the first guide blade is lower than 70%, the first guide blade begins to close, and when the load range of the first guide blade is 50%, the first guide blade is fully closed; if the load range of the first guide blade is lower than 50%, the first chilled water compressor begins to increase power, and when the load range of the first guide blade is 20%, the first chilled water compressor increases to a maximum of 130%;

[0031] If the value of the outlet water temperature T1 minus the inlet water temperature T2 is greater than the preset value T5, the first chilled water compressor is adjusted to operate at 150% of the current operating power, otherwise the first chilled water compressor operates at the current operating power;

[0032] S32: If the load range of the second guide blade is between 70% and 100%, the second guide blade is fully open; if the load range of the second guide blade is lower than 70%, the second guide blade begins to close, and when the load range of the second guide blade is 50%, the second guide blade is fully closed; if the load range of the second guide blade is lower than 50%, the second chilled water compressor begins to increase power, and when the load range of the second guide blade is 20%, the second chilled water compressor increases to a maximum of 130%;

[0033] If the value of the outlet water temperature T3 minus the inlet water temperature T4 is greater than the preset value T6, the second chilled water compressor is adjusted to operate at 150% of the current operating power, otherwise the second chilled water compressor operates at the current operating power.

[0034] The present invention has the following beneficial effects:

[0035] 1. Adjust the power of the chiller according to the water temperature difference between the inlet and outlet of the chiller and the load range of the guide vanes, so that the startup and operation of the chiller have obvious energy-saving effects;

[0036] 2. The use of frequency converter to drive the chiller improves the operating performance of the chiller, prevents surge, and enhances the flexibility of operation adjustment. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 is a system structure diagram of an embodiment of the present invention;

[0038] Figure 2 is a flow chart of a method according to an embodiment of the present invention;

[0039] The realization of the purpose, functional features and advantages of the present invention will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0040] It should be understood that the specific embodiments described herein are only used to explain the present invention, and are not used to limit the present invention.

[0041] Reference Figure 1 , the present invention provides a frequency converter controlled chiller energy saving system, comprising: an air supply unit 13, a hydrogen compressor 14, a first chiller unit, a second chiller unit, a heat exchanger 17, a hydrogenator 19, a dispersing unit 16 and a hydrogenation vehicle 20;

[0042] The air supply unit 13 is connected to the hydrogen compressor 14, the hydrogen compressor 14 is connected to the first cold water unit, the discharge port of the hydrogen compressor 14 is connected to the first inlet of the discharge unit 16, the hydrogen outlet of the hydrogen compressor 14 is connected to the air inlet of the heat exchanger 17, the heat exchanger 17 is connected to the second cold water unit, the air outlet of the heat exchanger 17 is connected to the air inlet of the hydrogenator 19, the filling port of the hydrogenator 19 is connected to the hydrogenation vehicle 20, and the discharge port of the hydrogenator 19 is connected to the second inlet of the discharge unit 16.

[0043] In this embodiment, the gas supply unit 13 is connected to the hydrogen compressor 14 as follows:

[0044] The nitrogen outlet of the gas supply unit 13 is connected to one end of the first gas valve 1, and the other end of the first gas valve 1 is connected to the nitrogen inlet of the hydrogen compressor 14;

[0045] The hydrogen outlet of the gas supply unit 13 is connected to one end of the second gas valve 2 , and the other end of the second gas valve 2 is connected to the hydrogen inlet of the hydrogen compressor 14 .

[0046] In this embodiment, the first cold water unit includes: a fourth water valve 4, a fifth water valve 5, a first temperature sensor 9, a second temperature sensor 10 and a first chiller 15;

[0047] The hydrogen compressor 14 is connected to the first cooling water unit in the following manner:

[0048] The water outlet of the hydrogen compressor 14 is connected to the second temperature sensor 10 and one end of the fifth water valve 5, and the other end of the fifth water valve 5 is connected to the water inlet of the first chiller 15;

[0049] The water inlet of the hydrogen compressor 14 is connected to the first temperature sensor 9 and one end of the fourth water valve 4 , and the other end of the fourth water valve 4 is connected to the water outlet of the first chiller 15 .

[0050] In this embodiment, the first chiller 15 includes: a first inverter, a first chiller compressor, a first cooling fan, a first controller and a first guide vane;

[0051] The first controller is electrically connected to the first temperature sensor 9, the second temperature sensor 10, the first frequency converter and the first guide vane, the frequency converter is electrically connected to the first cold water compressor, and the first cold water compressor is electrically connected to the first cooling fan;

[0052] In a specific implementation, the first chilled water compressor drives the impeller of the first cooling fan to rotate at high speed through the speed-increasing gear by the motor inside the first chilled water compressor. The centrifugal force of the high-speed rotation of the impeller compresses the refrigerant gas and converts most of the kinetic energy of the gas into pressure energy. Obviously, the energy obtained by the refrigerant gas from the impeller is ultimately input through the motor, and the input power of the motor satisfies the following relationship:

[0053] P=KDV / n

[0054] Wherein, P is the motor input power, D is the total pressure of the refrigerant gas, V is the volume flow rate of the refrigerant gas, n is the motor efficiency, and K is the calculation constant;

[0055] In the above formula, D is proportional to the square of the motor speed, and V is proportional to the motor speed. Therefore, it can be obtained that the motor power is proportional to the cube of the motor speed, that is, reducing the speed will greatly reduce the power, while improving the efficiency of the first chiller 15 and reducing the power consumption of the first chiller 15; the first inverter optimizes the motor speed and the opening of the first guide vane according to the outlet water temperature of the first chiller 15 and the pressure head of the first chiller compressor, so that the first chiller 15 always operates in the optimal state area; the basic parameter controlled by the first inverter is the temperature difference between the actual value and the set value of the chilled water outlet temperature; When the first chiller 15 is operating under full load conditions, the first guide vane is fully open, and the motor completes temperature difference control according to the speed logic. As the load decreases, the motor speed will decrease, and the motor will be controlled by the pressure head of the first chilled water compressor and the minimum allowable speed of the system until the speed reaches the minimum; at this time, the motor will remain at the minimum speed, and the motor speed will provide a signal to the control of the first guide vane to reduce the opening of the guide vane; as the load continues to decrease, the speed signal from the first chilled water compressor continues to close the first guide vane and further reduce the speed of the motor.

[0056] In this embodiment, the second cold water unit includes: a sixth water valve 6, a seventh water valve 7, a third temperature sensor 11, a fourth temperature sensor 12 and a second chiller 18;

[0057] The hydrogen outlet of the hydrogen compressor 14 is connected to the air inlet of the heat exchanger 17, and the heat exchanger 17 is connected to the second cold water unit, specifically:

[0058] The hydrogen outlet of the hydrogen compressor 14 is connected to one end of the third gas valve 3, and the other end of the third gas valve 3 is connected to the air inlet of the heat exchanger 17;

[0059] The water outlet of the heat exchanger 17 is connected to the fourth temperature sensor 12 and one end of the seventh water valve 7, and the other end of the seventh water valve 7 is connected to the water inlet of the second chiller 18;

[0060] The water inlet of the heat exchanger 17 is connected to the third temperature sensor 11 and one end of the sixth water valve 6 , and the other end of the sixth water valve 6 is connected to the water outlet of the second chiller 18 .

[0061] In this embodiment, the second chiller 18 includes: a second inverter, a second chiller compressor, a second cooling fan, a second controller and a second guide vane;

[0062] The second controller is electrically connected to the third temperature sensor 11, the fourth temperature sensor 12, the second frequency converter and the second guide vane, the frequency converter is electrically connected to the second cold water compressor, and the second cold water compressor is electrically connected to the second cooling fan;

[0063] In a specific implementation, the working principle of the second chiller 18 is the same as that of the first chiller 15 .

[0064] In this embodiment, the air outlet of the heat exchanger 17 is connected to the air inlet of the hydrogenator 19 in the following manner:

[0065] The gas outlet of the heat exchanger 17 is connected to one end of the eighth gas valve 8 , and the other end of the eighth gas valve 8 is connected to the gas inlet of the hydrogenator 19 .

[0066] The present invention provides a frequency converter-controlled chiller energy-saving method, which is implemented based on the frequency converter-controlled chiller energy-saving system, and includes the following steps:

[0067] S1: starting the energy-saving system of the water chiller controlled by the inverter, setting the load range of the first guide vane in the first water chiller 15 and the load range of the second guide vane in the second water chiller 18;

[0068] S2: The first temperature sensor 9 detects the outlet water temperature T1 of the first chiller 15 in real time, and the second temperature sensor 10 detects the inlet water temperature T2 of the first chiller 15 in real time; the third temperature sensor 11 detects the outlet water temperature T3 of the second chiller 18 in real time, and the fourth temperature sensor 12 detects the inlet water temperature T4 of the second chiller 18 in real time;

[0069] S3: Adjust the working state of the first chiller 15 according to the load range of the first guide vane, the outlet water temperature T1 of the first chiller 15 and the inlet water temperature T2 of the first chiller 15; adjust the working state of the second chiller 18 according to the load range of the second guide vane, the outlet water temperature T3 of the second chiller 18 and the inlet water temperature T4 of the second chiller 18.

[0070] In this embodiment, step S3 is specifically as follows:

[0071] S31: If the load range of the first guide blade is between 70% and 100%, the first guide blade is fully open; if the load range of the first guide blade is lower than 70%, the first guide blade begins to close, and when the load range of the first guide blade is 50%, the first guide blade is fully closed; if the load range of the first guide blade is lower than 50%, in order to avoid surge, the first chilled water compressor begins to increase power, and when the load range of the first guide blade is 20%, the first chilled water compressor increases to a maximum of 130%, which can effectively increase the operating range of the first chiller 15;

[0072] If the value of the outlet water temperature T1 minus the inlet water temperature T2 is greater than the preset value T5, the first chilled water compressor is adjusted to operate at 150% of the current operating power, otherwise the first chilled water compressor operates at the current operating power; the preset value T5 can be specifically set according to actual conditions;

[0073] S32: If the load range of the second guide blade is between 70% and 100%, the second guide blade is fully open; if the load range of the second guide blade is lower than 70%, the second guide blade begins to close, and when the load range of the second guide blade is 50%, the second guide blade is fully closed; if the load range of the second guide blade is lower than 50%, in order to avoid surge, the second chiller starts to increase power, and when the load range of the second guide blade is 20%, the second chiller increases to a maximum of 130%, which can effectively increase the operating range of the second chiller 18;

[0074] If the value of the water outlet temperature T3 minus the water inlet temperature T4 is greater than the preset value T6, the second water chiller is adjusted to operate at 150% of the current operating power, otherwise the second water chiller operates at the current operating power; the preset value T6 can be set specifically according to actual conditions.

[0075] It should be noted that, in this article, the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or system including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or system. In the absence of further restrictions, an element defined by the sentence "comprises a ..." does not exclude the existence of other identical elements in the process, method, article or system including the element.

[0076] The serial numbers of the embodiments of the present invention are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments. In a unit claim that lists several means, several of these means may be embodied by the same hardware item. The use of the words first, second, and third, etc. does not indicate any order and these words may be interpreted as identifiers.

[0077] The above are only preferred embodiments of the present invention, and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A frequency converter controlled chiller energy saving method, based on a frequency converter controlled chiller energy saving system, characterized in that: The inverter-controlled chiller energy-saving system comprises: an air supply unit (13), a hydrogen compressor (14), a first chiller unit, a second chiller unit, a heat exchanger (17), a hydrogenator (19), a venting unit (16) and a hydrogenation vehicle (20); The air supply unit (13) is connected to the hydrogen compressor (14), the hydrogen compressor (14) is connected to the first cold water unit, the discharge port of the hydrogen compressor (14) is connected to the first inlet of the discharge unit (16), the hydrogen outlet of the hydrogen compressor (14) is connected to the air inlet of the heat exchanger (17), the heat exchanger (17) is connected to the second cold water unit, the air outlet of the heat exchanger (17) is connected to the air inlet of the hydrogenator (19), the filling port of the hydrogenator (19) is connected to the hydrogenation vehicle (20), and the discharge port of the hydrogenator (19) is connected to the second inlet of the discharge unit (16); The first cold water unit comprises: a fourth water valve (4), a fifth water valve (5), a first temperature sensor (9), a second temperature sensor (10) and a first cold water unit (15); The hydrogen compressor (14) is connected to the first cooling water unit in the following manner: The water outlet of the hydrogen compressor (14) is connected to the second temperature sensor (10) and one end of the fifth water valve (5), and the other end of the fifth water valve (5) is connected to the water inlet of the first chiller (15); The water inlet of the hydrogen compressor (14) is connected to the first temperature sensor (9) and one end of the fourth water valve (4), and the other end of the fourth water valve (4) is connected to the water outlet of the first chiller (15); The second cold water unit comprises: a sixth water valve (6), a seventh water valve (7), a third temperature sensor (11), a fourth temperature sensor (12) and a second cold water unit (18); The hydrogen outlet of the hydrogen compressor (14) is connected to the air inlet of the heat exchanger (17), and the heat exchanger (17) is connected to the second cold water unit, specifically: The hydrogen outlet of the hydrogen compressor (14) is connected to one end of the third gas valve (3), and the other end of the third gas valve (3) is connected to the gas inlet of the heat exchanger (17); The water outlet of the heat exchanger (17) is connected to the fourth temperature sensor (12) and one end of the seventh water valve (7), and the other end of the seventh water valve (7) is connected to the water inlet of the second chiller (18); The water inlet of the heat exchanger (17) is connected to the third temperature sensor (11) and one end of the sixth water valve (6), and the other end of the sixth water valve (6) is connected to the water outlet of the second chiller (18); The inverter-controlled chiller energy-saving method comprises the following steps: S1: starting the energy-saving system of the water chiller controlled by the frequency converter, setting the load range of the first guide vane in the first water chiller (15), and the load range of the second guide vane in the second water chiller (18); S2: the first temperature sensor (9) detects the outlet water temperature T1 of the first chiller (15) in real time, and the second temperature sensor (10) detects the inlet water temperature T2 of the first chiller (15) in real time; the third temperature sensor (11) detects the outlet water temperature T3 of the second chiller (18) in real time, and the fourth temperature sensor (12) detects the inlet water temperature T4 of the second chiller (18) in real time; S3: adjusting the working state of the first chiller (15) according to the load range of the first guide vane, the outlet water temperature T1 of the first chiller (15) and the inlet water temperature T2 of the first chiller (15); adjusting the working state of the second chiller (18) according to the load range of the second guide vane, the outlet water temperature T3 of the second chiller (18) and the inlet water temperature T4 of the second chiller (18); Step S3 is specifically as follows: S31: If the load range of the first guide blade is between 70% and 100%, the first guide blade is fully open; if the load range of the first guide blade is lower than 70%, the first guide blade begins to close, and when the load range of the first guide blade is 50%, the first guide blade is fully closed; if the load range of the first guide blade is lower than 50%, the first chilled water compressor begins to increase power, and when the load range of the first guide blade is 20%, the first chilled water compressor increases to a maximum of 130%; If the value of the outlet water temperature T1 minus the inlet water temperature T2 is greater than the preset value T5, the first chilled water compressor is adjusted to operate at 150% of the current operating power, otherwise the first chilled water compressor operates at the current operating power; S32: If the load range of the second guide blade is between 70% and 100%, the second guide blade is fully open; if the load range of the second guide blade is lower than 70%, the second guide blade begins to close, and when the load range of the second guide blade is 50%, the second guide blade is fully closed; if the load range of the second guide blade is lower than 50%, the second chiller compressor begins to increase power, and when the load range of the second guide blade is 20%, the second chiller compressor increases to a maximum of 130%; If the value of the outlet water temperature T3 minus the inlet water temperature T4 is greater than the preset value T6, the second chilled water compressor is adjusted to operate at 150% of the current operating power, otherwise the second chilled water compressor operates at the current operating power.

2. The energy-saving method for a water chiller controlled by a frequency converter according to claim 1, characterized in that: The gas supply unit (13) is connected to the hydrogen compressor (14) in the following manner: The nitrogen outlet of the gas supply unit (13) is connected to one end of the first gas valve (1), and the other end of the first gas valve (1) is connected to the nitrogen inlet of the hydrogen compressor (14); The hydrogen outlet of the gas supply unit (13) is connected to one end of the second gas valve (2), and the other end of the second gas valve (2) is connected to the hydrogen inlet of the hydrogen compressor (14).

3. The energy-saving method for a chiller controlled by a frequency converter according to claim 1, characterized in that: The first water chiller (15) comprises: a first frequency converter, a first water chiller compressor, a first cooling fan, a first controller and a first guide vane; The first controller is electrically connected to the first temperature sensor (9), the second temperature sensor (10), the first frequency converter and the first guide vane; the frequency converter is electrically connected to the first cold water compressor; and the first cold water compressor is electrically connected to the first cooling fan.

4. The energy-saving method for a chiller controlled by a frequency converter according to claim 1, characterized in that: The second water chiller (18) comprises: a second frequency converter, a second water chiller compressor, a second cooling fan, a second controller and a second guide vane; The second controller is electrically connected to the third temperature sensor (11), the fourth temperature sensor (12), the second frequency converter and the second guide vane, the frequency converter is electrically connected to the second cold water compressor, and the second cold water compressor is electrically connected to the second cooling fan.

5. The energy-saving method for a chiller controlled by a frequency converter according to claim 1, characterized in that: The gas outlet of the heat exchanger (17) is connected to the gas inlet of the hydrogenator (19) in the following manner: The gas outlet of the heat exchanger (17) is connected to one end of the eighth gas valve (8), and the other end of the eighth gas valve (8) is connected to the gas inlet of the hydrogenator (19).

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