Ice machine non-condensable gas exhaust and refrigerant recovery system and control method

Abstract

The application belongs to the technical field of waste gas emission, and particularly discloses an ice machine non-condensable gas emission and refrigerant recovery system and a control method, which comprises a controller, a condenser, an intermediate tank, a non-condensable gas cooler, a non-condensable gas emission valve, a temperature control valve, a first pressure transmitter and a temperature transmitter; the intermediate tank is provided with a port a, a port b and a port c, the port a and the port c are located at the top of the intermediate tank, and the port b is located at the bottom of the intermediate tank; the non-condensable gas cooler is provided with three outlets and two inlets, the three outlets are a port d, a port e and a port f respectively, and the two inlets are a port h and a port g respectively. Through heat exchange, the refrigerant on the pipe side of the non-condensable gas cooler is condensed and then returns to the intermediate tank through the port f of the non-condensable gas cooler, the non-condensable gas passes through the port d of the non-condensable gas cooler and is finally emitted to a flare through the non-condensable gas emission valve, the liquid ammonia on the shell side of the non-condensable gas cooler after heat exchange is transported to a separator through the port e for separation, and the separated liquid ammonia returns to the system for recycling.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of waste gas emission, and particularly relates to an ice machine non-condensable gas emission and refrigerant recovery system and a control method. BACKGROUND

[0002] Currently, ammonia or propylene is generally used as refrigerant in large centrifugal refrigeration units in chemical systems. In the process of starting and normal operation of the compressor, nitrogen leaked from the dry gas seal, air and nitrogen that have not been replaced at the beginning of starting and other non-condensable gases exist in the refrigerant. If the air, nitrogen and other non-condensable gases are too much, it will lead to many problems such as increased power consumption of the entire compressor, insufficient refrigeration capacity, increased condensing temperature, high outlet pressure, increased condensing water and other problems, ultimately leading to increased energy consumption cost. Since the refrigerant and the non-condensable gas are mixed, if the mixture is directly discharged, it will lead to waste of refrigerant and increase the operation cost. SUMMARY

[0003] The purpose of the present application is to provide an ice machine non-condensable gas emission and refrigerant recovery system and a control method to solve the problem that directly discharging the mixture of refrigerant and non-condensable gas will lead to waste of refrigerant and increase the operation cost.

[0004] In order to achieve the above purpose, the technical scheme of the present application is as follows: an ice machine non-condensable gas emission and refrigerant recovery system, comprising a controller and a condenser, an intermediate tank, a non-condensable gas cooler, a non-condensable gas discharge valve, a temperature control valve, a first pressure transmitter and a temperature transmitter connected with the controller; the intermediate tank is provided with a port a, a port b and a port c, the port a and the port c are located at the top of the intermediate tank, and the port b is located at the bottom of the intermediate tank; the non-condensable gas cooler is provided with three outlets and two inlets, the three outlets are a port d, a port e and a port f respectively, and the two inlets are a port h and a port g respectively; the port d, the port g and the port f are located at the pipe side of the non-condensable gas cooler respectively, and the port e and the port h are located at the shell side of the non-condensable gas cooler respectively; the port a and the port f are connected by a first pipeline; the port c and the port g are connected by a second pipeline; the port b and the port h are connected by a third pipeline; the port e is connected with the outside through a fourth pipeline; the port d is connected with the outside through a fifth pipeline; the inlet of the condenser is connected with the outlet of the compressor through a sixth pipeline, and the outlet of the condenser is connected with the intermediate tank through a seventh pipeline; the temperature transmitter, the first pressure transmitter and the non-condensable gas discharge valve are sequentially arranged on the fifth pipeline in the flow direction; the temperature control valve is arranged on the third pipeline; the temperature control valve is used for controlling the temperature of the non-condensable gas cooler, and the non-condensable gas discharge valve is used for controlling the discharge flow of the non-condensable gas cooler.

[0005] Further, a separator connected with the controller is further included, and the separator is connected with the fourth pipeline.

[0006] Furthermore, it also includes a compressor outlet valve, a second pressure transmitter and a compressor outlet safety valve connected to the controller. The sixth pipeline is also connected to an eighth pipeline connected to the fifth pipeline. The compressor outlet safety valve is arranged on the sixth pipeline, and the second pressure transmitter and the compressor outlet valve are arranged in sequence in the flow direction of the eighth pipeline.

[0007] A method for controlling the discharge of non-condensable gas and the recovery of refrigerant from an ice machine, comprising:

[0008] The controller controls the opening of the temperature control valve and the non-condensable gas discharge valve according to the value of the first pressure transmitter;

[0009] If the temperature control valve and the non-condensable gas discharge valve are fully opened, the controller will control the opening of the compressor outlet valve according to the value of the second pressure transmitter;

[0010] If the compressor outlet valve is fully opened, the controller will control the opening of the compressor outlet safety valve according to the values ​​of the two pressure transmitters.

[0011] Furthermore, the controller controls the opening of the temperature control valve and the non-condensable gas discharge valve according to the value of the first pressure transmitter; the specific control method is:

[0012] When P1≥P 设 +0.05MPa(G), open the temperature control valve to 20% of its opening, and open the non-condensable gas discharge valve to 20% of its opening; where P1 is the value of the first pressure transmitter, P 设 is the design pressure value of the compressor outlet;

[0013] When P1≥P 设 +0.1MPa(G), open the temperature control valve to 40% of its opening, and open the non-condensable gas discharge valve to 40% of its opening;

[0014] When P1≥P 设 +0.15MPa(G), open the temperature control valve to 80% of its opening, and open the non-condensable gas discharge valve to 80% of its opening;

[0015] When P1≥P 设 +0.2MPa(G), open the temperature control valve to 100% of its opening, and open the non-condensable gas discharge valve to 100% of its opening;

[0016] When P1<P 设 When the pressure drops to -0.2 MPa(G), the temperature control valve and the non-condensable gas discharge valve are closed.

[0017] Furthermore, if the temperature control valve and the non-condensable gas discharge valve are fully opened, the controller will control the opening of the compressor outlet valve according to the value of the second pressure transmitter. The specific control method is:

[0018] When P2≥P 设 +0.10MPa(G), open the compressor outlet valve 10%; where P2 is the value of the second pressure transmitter, P 设 is the design pressure value of the compressor outlet;

[0019] When P2≥P 设 +0.20MPa(G), open the compressor outlet valve to 50% of its opening;

[0020] When P2≥P 设 +0.30MPa(G), open the compressor outlet valve to 100% opening;

[0021] When P2≤P 设 When the pressure drops to -0.05 MPa (G), the compressor outlet valve is closed.

[0022] Furthermore, if the compressor outlet valve is fully opened, the controller will control the opening of the compressor outlet safety valve according to the values ​​of the two pressure transmitters. The specific control method is: when P2 ≥ 2.2 MPa (G), the compressor outlet safety valve is fully opened.

[0023] The working principle of this technical solution is:

[0024] The mixed gas discharged from the compressor outlet is condensed through the condenser and then enters the intermediate tank. The non-condensable gas and refrigerant enter the tube side of the non-condensable gas cooler through the c port of the intermediate tank and the g port of the non-condensable gas cooler. The liquid ammonia enters the shell side of the non-condensable gas cooler through the b port of the intermediate tank and the h port of the non-condensable gas cooler. The evaporation temperature is adjusted by the temperature controller on the third pipeline, so that the refrigerant on the tube side of the non-condensable gas cooler is condensed through heat exchange and then returns to the intermediate tank along the f port of the non-condensable gas cooler. The non-condensable gas is finally discharged to the flare for combustion through the d port of the non-condensable gas cooler and the non-condensable gas discharge valve. The liquid ammonia after heat exchange on the shell side of the non-condensable gas cooler is transported to the separator through the e port for separation, and the separated liquid ammonia is returned to the system for recycling.

[0025] When P1≥P 设 When the pressure is +0.05MPa(G), open the temperature control valve to 20% of its opening and the non-condensable gas discharge valve to 20% of its opening;

[0026] When P1≥P 设 When the pressure is +0.1MPa(G), open the temperature control valve to 40% of its opening and the non-condensable gas discharge valve to 40% of its opening;

[0027] When P1≥P 设 When the pressure is +0.15MPa(G), open the temperature control valve to 80% of its opening and the non-condensable gas discharge valve to 80% of its opening;

[0028] When P1≥P 设 When the pressure is +0.2MPa(G), open the temperature control valve to 100% and the non-condensable gas discharge valve to 100%;

[0029] When P1<P 设 When the pressure is -0.2MPa(G), close the temperature control valve and the non-condensable gas discharge valve at the same time.

[0030] To ensure the safety of the unit, a compressor outlet valve and a compressor outlet safety valve are also provided at the compressor outlet. When the increase of P1 causes the increase of P2, the compressor outlet valve can be adjusted. The specific adjustment method is as follows:

[0031] When P2≥P 设 When the pressure is +0.10MPa(G), open the compressor outlet valve to 10% of its opening;

[0032] When P2≥P 设 When the pressure is +0.20MPa(G), open the compressor outlet valve to 50% of its opening;

[0033] When P2≥P 设 When the pressure is +0.30MPa(G), open the compressor outlet valve to 100% of its opening;

[0034] When the compressor outlet valve is fully opened and P2≥2.2MPa(G), the compressor outlet safety valve is fully opened;

[0035] When P2≤P 设 When the pressure reaches -0.05MPa(G), close the compressor outlet valve.

[0036] The beneficial effects of this technical solution are:

[0037] A non-condensable gas cooler is set up to utilize the different condensation temperatures of different gases to condense the refrigerant from the mixed gas into liquid (the condensation temperature is controlled by a temperature control valve), and then flow it back to the intermediate tank. The separated non-condensable gas is discharged to the flare for combustion through the non-condensable gas discharge valve. The recovery system and control method of this technical solution can effectively discharge non-condensable gas, eliminating many problems caused by the presence of non-condensable gas, such as increased compressor power consumption, insufficient cooling capacity, increased condensation temperature, high outlet pressure, etc., and can also prevent waste of refrigerant. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1The principle diagram of the ice machine non-condensable gas emission and refrigerant recovery system of the present application;

[0039] Figure 2 The flow chart of the control method of the ice machine non-condensable gas emission and refrigerant recovery of the present application. DETAILED DESCRIPTION

[0040] The following will be further described in detail through specific embodiments:

[0041] The reference signs in the attached drawings of the specification include: compressor 1, condenser 2, non-condensable gas cooler 3, non-condensable gas emission valve 4, temperature control valve 5, first pressure transmitter 6, temperature transmitter 7, separator 8, compressor outlet valve 9, second pressure transmitter 10, compressor outlet safety valve 11, first pipeline 12, second pipeline 13, third pipeline 14, fourth pipeline 15, fifth pipeline 16, sixth pipeline 17, seventh pipeline 18, eighth pipeline 19, intermediate tank 20.

[0042] The technical solutions in the embodiments of the present application will be described clearly and completely below in combination with the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all the other embodiments obtained by those of ordinary skill in the art without creative work, belong to the scope of protection of the present application.

[0043] Embodiment one

[0044] Basically as the attached Figure 1The figure shows a non-condensable gas discharge and refrigerant recovery system for a refrigerator, including a controller, a condenser 2 connected to the controller, an intermediate tank 20, a non-condensable gas cooler 3, a separator 8, a non-condensable gas discharge valve 4, a temperature control valve 5, a first pressure transmitter 6, a temperature transmitter 7, a compressor outlet valve 9, a second pressure transmitter 10, and a compressor outlet safety valve 11. The intermediate tank 20 is provided with ports a, b, and c. Ports a and c are located at the top of the intermediate tank 20, while port b is located at the bottom. The non-condensable gas cooler 3 has three outlets and two inlets: ports d, e, and f. The two inlets are ports h and g. Ports d, g, and f are located on the tube side of the non-condensable gas cooler 3, while ports e and h are located on the shell side. Ports a and f are connected via a first pipe 12; ports c and g are connected via a second pipe 13; ports b and h are connected via a third pipe 14; port e is connected to separator 8 via a fourth pipe 15; and port d is connected to the outside world via a fifth pipe 16. The inlet of condenser 2 is connected to the outlet of compressor 1 via a sixth pipe 17, and the outlet of condenser 2 is connected to intermediate tank 20 via a seventh pipe 18. A temperature transmitter 7, a first pressure transmitter 6, and a non-condensable gas discharge valve 4 are sequentially arranged along the flow direction of the fifth pipe 16. A temperature control valve 5 is provided on the third pipe 14. An eighth pipe 19, which is connected to the sixth pipe 17 and communicates with the fifth pipe 16, is also connected to the sixth pipe 17. The compressor outlet safety valve 11 is also provided on the sixth pipe 17. A second pressure transmitter 10 and a compressor outlet valve 9 are sequentially arranged along the flow direction of the eighth pipe 19. The temperature control valve 5 controls the temperature of the non-condensable gas cooler 3, and the non-condensable gas discharge valve 4 controls the discharge flow of the non-condensable gas cooler 3.

[0045] Example 2

[0046] Basically as attached Figure 2 As shown: A method for controlling the discharge of non-condensable gas from an ice machine and the recovery of refrigerant, according to the method for controlling the discharge of non-condensable gas from an ice machine and the recovery of refrigerant in the first embodiment, comprising:

[0047] S1: The controller controls the opening of the temperature control valve 5 and the non-condensable gas discharge valve 4 according to the value of the first pressure transmitter 6; the specific control method is:

[0048] When P1≥P 设 +0.05MPa(G), open the temperature control valve 5 to 20% of its opening, and open the non-condensable gas discharge valve 4 to 20% of its opening; where P1 is the value of the first pressure transmitter 6, P 设 is the design pressure value of the outlet of compressor 1;

[0049] When P1≥P 设When P1≥P

[0050] When P1≥P 设 When P1≥P

[0051] When P1≥P 设 When P1≥P

[0052] When P1 设 When P1

[0053] S2: If the temperature control valve 5 and the non-condensable gas discharge valve 4 are fully opened, the controller will control the opening of the compressor outlet valve 9 according to the value of the second pressure transmitter 10. The specific control method is as follows:

[0054] When P2≥P 设 When P2≥P 设 is the design pressure value of the compressor 1 outlet;

[0055] When P2≥P 设 When P2≥P

[0056] When P2≥P 设 When P2≥P

[0057] When P2≤P 设 When P2≤P

[0058] S3: If the compressor outlet valve 9 is fully opened, the controller will control the opening of the compressor outlet safety valve 11 according to the value of the second pressure transmitter 10. The specific control method is as follows: When P2≥2.2MPa(G), the compressor outlet safety valve 11 is fully opened.

[0059] The specific implementation process is as follows:

[0060] The mixed gas discharged from the compressor 1 outlet passes through the condenser 2 to be condensed and enters the intermediate tank 20. The non-condensable gas and the refrigerant enter the non-condensable gas cooler 3 through the c port of the intermediate tank 20 and the g port of the non-condensable gas cooler 3. The liquid ammonia enters the non-condensable gas cooler 3 through the b port of the intermediate tank 20 and the h port of the non-condensable gas cooler 3. The evaporation temperature is adjusted by the temperature controller on the third pipeline 14, so that the refrigerant on the tube side of the non-condensable gas cooler 3 is condensed by heat exchange and returns to the intermediate tank 20 through the f port of the non-condensable gas cooler 3. The non-condensable gas passes through the d port of the non-condensable gas cooler 3 and is finally discharged to the flare through the non-condensable gas discharge valve 4. The liquid ammonia on the shell side of the non-condensable gas cooler 3 is transported to the separator 8 through the e port after heat exchange, and the separated liquid ammonia returns to the system for recycling.

[0061] When P1≥P 设 +0.05MPa(G), open the temperature control valve 5 at 20% of the opening, and open the non-condensable gas discharge valve 4 at 20% of the opening.

[0062] When P1≥P 设 +0.1MPa(G), open the temperature control valve 5 at 40% of the opening, and open the non-condensable gas discharge valve 4 at 40% of the opening.

[0063] When P1≥P 设 +0.15MPa(G), open the temperature control valve 5 at 80% of the opening, and open the non-condensable gas discharge valve 4 at 80% of the opening.

[0064] When P1≥P 设 +0.2MPa(G), open the temperature control valve 5 at 100% of the opening, and open the non-condensable gas discharge valve 4 at 100% of the opening.

[0065] When P1 设 -0.2MPa(G), close the temperature control valve 5 and the non-condensable gas discharge valve 4 at the same time.

[0066] To ensure the safety of the unit, a compressor outlet valve 9 and a compressor outlet safety valve 11 are also provided at the outlet of the compressor 1. When P1 rises and causes P2 to rise, the compressor outlet valve 9 can be adjusted. The specific adjustment method is as follows:

[0067] When P2≥P 设 +0.10MPa(G), open the compressor outlet valve 9 at 10% of the opening.

[0068] When P2≥P 设 +0.20MPa(G), open the compressor outlet valve 9 at 50% of the opening.

[0069] When P2≥P 设+0.30 MPa(G) the compressor outlet valve 9 is opened 100% of its opening;

[0070] When the compressor outlet valve 9 is fully open and when P2≥2.2 MPa(G) then the compressor outlet safety valve 11 is fully open;

[0071] When P2≤P 设 -0.05 MPa(G) the compressor outlet valve 9 is closed.

[0072] It has to be noted that the terms "first", "second", and the like in the description do not by themselves denote any order, quantity, or importance, but are used to identify a hardware component. Furthermore, the terms "comprises", "comprising", or other variations thereof do not by themselves indicate that a hardware component includes all the features described above, but rather that the hardware component includes at least the features specifically mentioned. In addition, terms such as "comprise", "comprising", or the like should not be interpreted as implying that the hardware component includes all the features of the specific examples described above, but rather that the hardware component includes at least the features specifically mentioned.

[0073] The above description is only some embodiments of the present application, and the common knowledge of the specific structure and characteristics in the scheme is not described too much. The ordinary skilled person in the art knows all the ordinary technical knowledge in the field of the application before the application date or the priority date, can know all the prior art in the field, and has the ability to apply the conventional experimental means before the date. The ordinary skilled person in the art can improve and implement the scheme under the guidance of this application combined with their own ability. Some typical known structures or known methods should not be an obstacle for the ordinary skilled person in the art to implement the present application. It should be pointed out that for those skilled in the art, without departing from the structure of the present application, a number of modifications and improvements can be made, which should be regarded as the protection scope of the present application. These will not affect the effect and practicality of the present application. The protection scope of the present application should be subject to the content of its claims, and the specific implementation mode in the specification can be used to explain the content of the claims.

Claims

1. The non-condensable gas discharge and refrigerant recovery system of the ice machine is characterized by: The utility model comprises a controller and a separator connected to the controller, a condenser, an intermediate tank, a non-condensable gas cooler, a non-condensable gas discharge valve, a temperature control valve, a first pressure transmitter, a temperature transmitter, a compressor outlet valve, a second pressure transmitter and a compressor outlet safety valve; the intermediate tank is provided with a port a, a port b and a port c, the ports a and c are located at the top of the intermediate tank, and the port b is located at the bottom of the intermediate tank; the non-condensable gas cooler is provided with three outlets and two inlets, the three outlets are port d, port e and port f, and the two inlets are port h and port g; the port d, port g and port f are respectively located on the tube side of the non-condensable gas cooler, and the port e and port h are respectively located on the shell side of the non-condensable gas cooler; the port a and port f are connected by a first pipeline; the port c and port g are connected by a second pipeline; the port b and port h are connected by a second pipeline. Three pipelines are connected; the e port is connected to the outside world through a fourth pipeline, and the separator is connected to the fourth pipeline; the d port is connected to the outside world through a fifth pipeline; the inlet of the condenser is connected to the outlet of the compressor through a sixth pipeline, and the sixth pipeline is also connected to an eighth pipeline connected to the fifth pipeline, the compressor outlet safety valve is provided on the sixth pipeline, and the second pressure transmitter and the compressor outlet valve are sequentially provided in the flow direction of the eighth pipeline; the outlet of the condenser is connected to the intermediate tank through a seventh pipeline; the temperature transmitter, the first pressure transmitter and the non-condensable gas discharge valve are sequentially provided on the fifth pipeline along the flow direction, and a temperature control valve is provided on the third pipeline; the temperature control valve is used to control the temperature of the non-condensable gas cooler, and the non-condensable gas discharge valve is used to control the discharge flow of the non-condensable gas cooler; The method for controlling the non-condensable gas discharge and refrigerant recovery system of the ice machine includes: The controller controls the opening of the temperature control valve and the non-condensable gas discharge valve according to the value of the first pressure transmitter; If the temperature control valve and the non-condensable gas discharge valve are fully opened, the controller will control the opening of the compressor outlet valve according to the value of the second pressure transmitter; If the compressor outlet valve is fully opened, the controller will control the opening of the compressor outlet safety valve according to the values ​​of the two pressure transmitters.

2. The non-condensable gas discharge and refrigerant recovery system for an ice machine according to claim 1, characterized in that: The controller controls the opening of the temperature control valve and the non-condensable gas discharge valve according to the value of the first pressure transmitter; the specific control method is: When P1≥P 设 +0.05MPa(G), open the temperature control valve to 20% of its opening, and open the non-condensable gas discharge valve to 20% of its opening; where P1 is the value of the first pressure transmitter, P 设 is the design pressure value of the compressor outlet; When P1≥P 设 +0.1MPa(G), open the temperature control valve to 40% of its opening, and open the non-condensable gas discharge valve to 40% of its opening; When P1≥P 设 +0.15MPa(G), open the temperature control valve to 80% of its opening, and open the non-condensable gas discharge valve to 80% of its opening; When P1≥P 设 +0.2MPa(G), open the temperature control valve to 100% of its opening, and open the non-condensable gas discharge valve to 100% of its opening; When P1<P 设 When the pressure drops to -0.2 MPa(G), the temperature control valve and the non-condensable gas discharge valve are closed.

3. The non-condensable gas discharge and refrigerant recovery system for an ice machine according to claim 1, characterized in that: If the temperature control valve and the non-condensable gas discharge valve are fully opened, the controller will control the opening of the compressor outlet valve according to the value of the second pressure transmitter. The specific control method is: When P2≥P 设 +0.10MPa(G), open the compressor outlet valve 10%; where P2 is the value of the second pressure transmitter, P 设 is the design pressure value of the compressor outlet; When P2≥P 设 +0.20MPa(G), open the compressor outlet valve to 50% of its opening; When P2≥P 设 +0.30MPa(G), open the compressor outlet valve to 100% opening; When P2≤P 设 When the pressure drops to -0.05 MPa (G), the compressor outlet valve is closed.

4. The non-condensable gas discharge and refrigerant recovery system for an ice machine according to claim 1, characterized in that: If the compressor outlet valve is fully opened, the controller will control the opening of the compressor outlet safety valve according to the values ​​of the two pressure transmitters. The specific control method is: when P2 ≥ 2.2 MPa (G), the compressor outlet safety valve is fully opened.

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