Refrigerating system for liquid carbon dioxide production
By setting a liquid ammonia storage tank and 气 ammonia liquefaction unit in the refrigeration system produced by liquid carbon dioxide, the level of cooling and the unified liquefaction of carbon dioxide can be achieved, and the cost of traditional ammonia ice machine systems is high, large occupied, power consumption is large, and power consumption is large. The problem of unsafe achieves energy conservation, safety and stable operation of the refrigeration system.
Patent Information
- Application Number
- CN202420280440.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-02-05
- Publication Date
- 2025-01-24
- Estimated Expiration
- 2034-02-05
AI Technical Summary
In the liquid phase carbon dioxide production process, traditional ammonia ice machine systems have problems such as high purchase cost, large area, large power consumption and unfavorable for safe and stable operation.
Design a refrigeration system for liquid carbon dioxide production. By setting up liquid ammonia storage tanks and iliac -ammonia liquefaction units to achieve a step -by -step cooling of carbon dioxide, and uniform liquefied refrigerant through lydosate liquefaction unit, change the traditional cold volume and connect to the connection method to change to the change to the change to change to Connect in series.
It achieves carbon dioxide-saving raw material preparation, reduces purchase costs and equipment footprint, simplifies operations, ensures safe and stable operation of the system, and saves energy consumption.
Smart Images
Figure CN222393174U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of accessory components for liquid carbon dioxide production, in particular to a refrigeration system for liquid carbon dioxide production. Background Art
[0002] With the rapid development of modern industry, on the one hand, carbon dioxide as the main producer of the greenhouse effect has received more and more attention; on the other hand, carbon dioxide has the property of extinguishing fire, and is safe, reliable and economical. Furthermore, liquid carbon dioxide can be used as a refrigerant to preserve food, can be used for artificial rainfall, and can also be used as an industrial raw material for the production of soda ash, urea and soda.
[0003] In the production process of liquid carbon dioxide, it is generally necessary to use a refrigerant to exchange heat with gaseous carbon dioxide to condense the gaseous phase of carbon dioxide into a liquid phase, and the refrigerant enters the corresponding condensers at each level respectively, and the gaseous phase carbon dioxide is gradually liquefied through step-by-step cooling. At the same time, the refrigerant in each level of condensers is vaporized, and after vaporization, it needs to be liquefied by different ammonia ice machines (and in conjunction with evaporative condensers) to achieve the characteristics of recycling; the above process requires the installation of multiple ammonia ice machines, which not only has a high purchase cost and occupies a large area, but also requires each ammonia ice machine to be turned on separately, which has the defects of high power consumption and is not conducive to safe and stable operation. Utility Model Content
[0004] The purpose of the utility model is to provide a refrigeration system for producing liquid carbon dioxide to solve the problems raised in the above background technology.
[0005] In order to achieve the above purpose, the utility model provides the following technical solutions:
[0006] A refrigeration system for liquid carbon dioxide production, comprising a carbon dioxide product gas pipeline, the carbon dioxide product gas pipeline sequentially enters the first channel of a primary condenser and the first channel of a secondary condenser, the liquid phase outlet of the first channel of the secondary condenser enters a subsequent process section, the refrigeration system also comprises a liquid ammonia storage tank, the outlet of the liquid ammonia storage tank is connected to the second channel of the primary condenser, the liquid phase outlet of the second channel of the primary condenser is connected to the second channel of the secondary condenser, the gas phase outlet of the second channel of the primary condenser and the gas phase outlet of the second channel of the secondary condenser are connected to the inlet of the liquid ammonia storage tank through a gas ammonia liquefaction unit.
[0007] The beneficial effects of the utility model are as follows: the utility model can realize step-by-step cooling of carbon dioxide by setting a liquid ammonia storage tank and allowing the liquid ammonia to enter the primary condenser and the secondary condenser in sequence, so as to achieve the purpose of saving raw materials when preparing liquid carbon dioxide; the refrigerant through the primary condenser and the secondary condenser can liquefy the gaseous ammonia through the gaseous ammonia liquefaction unit, so as to achieve the advantages of reducing purchase cost, reducing equipment footprint, facilitating operation and achieving safe and stable operation of the system.
[0008] Preferably, the gas-ammonia liquefaction unit comprises at least an ammonia compressor and an evaporative condenser; the ammonia compressor is a two-stage compression ammonia compressor, the gas phase outlet of the second channel of the secondary condenser is connected to the primary compression gas phase inlet of the ammonia compressor, the gas phase outlet of the second channel of the primary condenser and the primary compression gas phase outlet of the ammonia compressor are respectively connected to the secondary compression gas phase inlet of the ammonia compressor; the gas phase outlet of the ammonia compressor is connected to the inlet of the liquid ammonia storage tank through the evaporative condenser.
[0009] Preferably, the gas-ammonia liquefaction unit also includes a primary buffer separation tank and a secondary buffer separation tank; the inlet of the primary buffer separation tank is connected to the gas phase outlet of the second channel of the secondary condenser, and the gas phase outlet of the primary buffer separation tank is connected to the primary compressed gas phase inlet of the ammonia compressor; the inlet of the secondary buffer separation tank is respectively connected to the gas phase outlet of the second channel of the primary condenser and the primary compressed gas phase outlet of the ammonia compressor, and the gas phase outlet of the secondary buffer separation tank is connected to the secondary compressed gas phase inlet of the ammonia compressor.
[0010] Preferably, a first valve is provided between the gas phase outlet of the first buffer separation tank and the first compressed gas phase inlet of the ammonia compressor, a second valve is provided between the gas phase outlet of the second channel of the first condenser and the inlet of the second buffer separation tank, a third valve is provided between the first compressed gas phase outlet of the ammonia compressor and the inlet of the second buffer separation tank, and a fourth valve is provided between the gas phase outlet of the second buffer separation tank and the second compressed gas phase inlet of the ammonia compressor.
[0011] Preferably, the gas-ammonia liquefaction unit also includes a heat exchanger arranged between the ammonia compressor and the evaporative condenser, and the gas phase outlet of the ammonia compressor is connected to the inlet of the evaporative condenser through the first channel of the heat exchanger; the exhaust gas outlet of the first channel of the secondary condenser is connected to the carbon dioxide exhaust gas treatment device through the second channel of the heat exchanger.
[0012] Preferably, the inlet end of the carbon dioxide product gas pipeline is connected to the product gas outlet of the distillation tower, and the liquid phase outlet of the first channel of the secondary condenser is connected to the reflux port of the distillation tower.
[0013] Preferably, the liquid ammonia storage tank is provided with a liquid ammonia replenishing pipeline with a liquid ammonia valve.
[0014] A refrigeration system for liquid carbon dioxide production made according to the above scheme changes the connection mode of connecting the cooling capacity with each stage of condensers in parallel in the traditional technology to a series connection mode; and in the subsequent process, the state of the refrigerant after gasification is converted into liquid through the gas-ammonia liquefaction unit, so as to achieve the characteristic of refrigerant recycling. By setting the gas-ammonia liquefaction unit, the gas phase refrigerant can be uniformly liquefied, which not only reduces the floor space of the equipment, but also achieves the characteristic of convenient control to maintain the operation safety of the entire system; further, the gas-ammonia liquefaction unit described in the utility model includes an ammonia compressor and an evaporative condenser, and the ammonia compressor is a two-stage ammonia compressor, and by allowing gas ammonia of different pressures to enter different inlets of the two-stage ammonia compressor, the same ammonia compressor can process gas ammonia from different condensers, so as to achieve the characteristics of reducing investment cost, equipment floor space and easy operation; further, a second heat exchanger is provided in the utility model, and by exchanging heat between the carbon dioxide tail gas and the compressed gas ammonia, not only the cooling capacity of the carbon dioxide tail gas can be effectively utilized to meet the emission requirements in the subsequent process, but also the energy consumption of the evaporative condenser can be saved. BRIEF DESCRIPTION OF THE DRAWINGS
[0015] Figure 1 It is a structural schematic diagram of the utility model.
[0016] In the figure: 1. Carbon dioxide product gas pipeline; 2. Primary condenser; 3. Secondary condenser; 4. Liquid ammonia feed pipeline; 5. Distillation tower; 6. Reflux port; 7. Liquid ammonia valve; 8. Liquid ammonia storage tank; 9. Ammonia compressor; 10. Heat exchanger; 11. Evaporative condenser; 12. Primary buffer separation tank; 13. Secondary buffer separation tank; 14. First valve; 15. Second valve; 16. Third valve; 17. Fourth valve; 18. Carbon dioxide tail gas treatment device. DETAILED DESCRIPTION
[0017] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the accompanying drawings in the embodiments of the present invention.
[0018] Reference Figure 1As shown, a refrigeration system for liquid carbon dioxide production includes a carbon dioxide product gas pipeline 1, which passes through the first channel of the first condenser 2 and the first channel of the second condenser 3 in sequence, and the liquid phase outlet of the first channel of the second condenser 3 enters the subsequent process section. The refrigeration system also includes a liquid ammonia storage tank 8, the outlet of the liquid ammonia storage tank 8 is connected to the second channel of the first condenser 2, the liquid phase outlet of the second channel of the first condenser 2 is connected to the second channel of the second condenser 3, and the gas phase outlet of the second channel of the first condenser 2 and the gas phase outlet of the second channel of the second condenser 3 are connected to the inlet of the liquid ammonia storage tank 8 through a gas ammonia liquefaction unit. The utility model changes the connection mode of the liquid ammonia storage tank 8 in parallel with the primary condenser 2 and the secondary condenser 3 in the traditional technology, so that the primary condenser 2 and the secondary condenser 3 are connected in series to achieve the characteristic of convenient control, and at the same time, the vaporized refrigerant in the primary condenser 2 and the secondary condenser 3 enters the gas ammonia liquefaction unit for unified liquefaction, so as to achieve the advantages of reducing the purchase cost, reducing the equipment footprint, facilitating operation and realizing safe and stable operation of the system; the gas ammonia liquefaction unit mainly includes a pressurizing device and a device for liquefying the gas phase refrigerant.
[0019] Further, the gas-ammonia liquefaction unit at least includes an ammonia compressor 9 and an evaporative condenser 11; the ammonia compressor 9 is a two-stage ammonia compressor, the gas phase outlet of the second channel of the secondary condenser 3 is connected to the primary compressed gas phase inlet of the ammonia compressor 9, the gas phase outlet of the second channel of the primary condenser 2 and the primary compressed gas phase outlet of the ammonia compressor 9 are respectively connected to the secondary compressed gas phase inlet of the ammonia compressor 9; the gas phase outlet of the ammonia compressor 9 is connected to the inlet of the liquid ammonia storage tank 8 through the evaporative condenser 11. The gas phase pressure in the gas phase outlet of the second channel of the primary condenser 2 is relatively high, and the gas phase pressure in the gas phase outlet of the second channel of the secondary condenser 3 is relatively low. Through the above arrangement, the gas phase in the gas phase outlet of the second channel of the secondary condenser 3 enters the primary compressed gas phase inlet of the ammonia compressor 9 for compression, and the gas phase in the primary compressed gas phase outlet of the ammonia compressor 9 and the gas phase outlet of the second channel of the primary condenser 2 enters the secondary compressed gas phase inlet of the ammonia compressor 9 for compression, so as to meet the purpose of using the same ammonia compressor 9 to compress gas phases of different pressures.
[0020] Furthermore, the gas-ammonia liquefaction unit also includes a primary buffer separation tank 12 and a secondary buffer separation tank 13; the inlet of the primary buffer separation tank 12 is connected to the gas phase outlet of the second channel of the secondary condenser 3, and the gas phase outlet of the primary buffer separation tank 12 is connected to the primary compressed gas phase inlet of the ammonia compressor 9; the inlet of the secondary buffer separation tank 13 is respectively connected to the gas phase outlet of the second channel of the primary condenser 2 and the primary compressed gas phase outlet of the ammonia compressor 9, and the gas phase outlet of the secondary buffer separation tank 13 is connected to the secondary compressed gas phase inlet of the ammonia compressor 9. By setting up a first-level buffer separation tank 12, the gas phase at the gas phase outlet of the second channel of the secondary condenser 3 can be separated into gas and liquid, so as to avoid entraining liquid ammonia and affecting the service life of the ammonia compressor 9; by setting up a second-level buffer separation tank 13, not only the gas phase at the gas phase outlet of the second channel of the first-level buffer separation tank 12 can be separated into gas and liquid, but also the gas phase from the first-level compressed gas phase outlet of the ammonia compressor 9 can be mixed with the gas phase at the gas phase outlet of the second channel of the first-level buffer separation tank 12 to achieve the characteristic of uniform pressure, thereby laying a foundation for the stable operation of the ammonia compressor 9.
[0021] Furthermore, a first valve 14 is provided between the gas phase outlet of the primary buffer separation tank 12 and the primary compressed gas phase inlet of the ammonia compressor 9, a second valve 15 is provided between the gas phase outlet of the second channel of the primary condenser 2 and the inlet of the secondary buffer separation tank 13, a third valve 16 is provided between the primary compressed gas phase outlet of the ammonia compressor 9 and the inlet of the secondary buffer separation tank 13, and a fourth valve 17 is provided between the gas phase outlet of the secondary buffer separation tank 13 and the secondary compressed gas phase inlet of the ammonia compressor 9. The above-mentioned arrangement can realize the characteristic of flexible control.
[0022] Furthermore, the gas-ammonia liquefaction unit further includes a heat exchanger 10 disposed between the ammonia compressor 9 and the evaporative condenser 11, and the gas phase outlet of the ammonia compressor 9 is connected to the inlet of the evaporative condenser 11 through the first channel of the heat exchanger 10; the tail gas outlet of the first channel of the secondary condenser 3 is connected to the carbon dioxide tail gas treatment device 18 through the second channel of the heat exchanger 10. The utility model uses carbon dioxide tail gas as a refrigerant to exchange heat with the compressed gas phase, which can not only achieve the characteristic of saving cooling capacity, but also avoid the consumption of steam caused by the reheating of the tail gas; the carbon dioxide tail gas treatment device 18 can be a venting device.
[0023] Furthermore, the inlet end of the carbon dioxide product gas pipeline 1 is connected to the product gas outlet of the distillation tower 5 , and the liquid phase outlet of the first channel of the secondary condenser 3 is connected to the reflux port 6 of the distillation tower 5 .
[0024] The liquid ammonia storage tank 8 is provided with a liquid ammonia supply pipeline 4 with a liquid ammonia valve 7 .
[0025] The working principle of the utility model is as follows: the gaseous carbon dioxide in the product gas outlet of the distillation tower 5 enters the first channel of the primary condenser 2 and the first channel of the secondary condenser 3 in turn through the carbon dioxide product gas pipeline 1 for heat exchange. During the heat exchange process, the gas phase gradually turns into the liquid phase, and the liquid carbon dioxide enters the reflux port 6 of the distillation tower 5 for use as reflux liquid; in the above process, the liquid ammonia in the liquid ammonia storage tank 8 enters the second channel of the primary condenser 2 (the liquid ammonia pressure at this time is about 0.1Mpag, and the temperature is -15°C) to exchange heat with carbon dioxide, and the liquid phase after heat exchange enters the second channel of the secondary condenser 3 (the liquid ammonia pressure at this time is about 0.01Mpag, and the temperature is -25°C) to further exchange heat with carbon dioxide; the gaseous ammonia after heat exchange through the secondary condenser 3 enters the primary buffer separation tank 12 for buffering and gas-liquid separation, and the gas phase after gas-liquid separation enters the primary compressed gas phase inlet of the ammonia compressor 9 for compression, and the gas at the primary compressed gas phase outlet of the ammonia compressor 9 is compressed. The gas phase passes through the primary condenser 2 and enters the secondary buffer separation tank 13 for buffering and gas-liquid separation. The gas phase after gas-liquid separation enters the secondary compression gas phase inlet of the ammonia compressor 9 for compression. The pressure of the compressed gas ammonia is about 1.2Mpag and the temperature is 50-60°C; it enters the heat exchanger 10 and exchanges heat with the non-condensable gas in the first channel passing through the secondary condenser 3 (the temperature of the non-condensable gas is about -20°C); the above process can not only reheat the non-condensable gas to facilitate subsequent venting operations on the basis of energy saving; it can also save cold energy to cool the pressurized gas ammonia; the cooled gas ammonia is converted into liquid ammonia through the evaporative condenser 11 and enters the liquid ammonia storage tank 8 for recycling; the above process has the advantages of reducing purchase costs and reducing equipment footprint; because the gas ammonia is uniformly liquefied, it is easy to operate, which is conducive to the safe and stable operation of the system. At the same time, by utilizing the cold energy in the non-condensable gas when producing carbon dioxide, it has the advantage of saving energy consumption.
[0026] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.
Claims
1. A refrigeration system for producing liquid carbon dioxide, comprising a carbon dioxide product gas pipeline (1), the carbon dioxide product gas pipeline (1) sequentially passes through the first channel of a primary condenser (2) and the first channel of a secondary condenser (3), and the liquid phase outlet of the first channel of the secondary condenser (3) enters a subsequent process section, characterized in that: The refrigeration system further comprises a liquid ammonia storage tank (8), the outlet of the liquid ammonia storage tank (8) being connected to the second channel of the primary condenser (2), the liquid phase outlet of the second channel of the primary condenser (2) being connected to the second channel of the secondary condenser (3), and the gas phase outlet of the second channel of the primary condenser (2) and the gas phase outlet of the second channel of the secondary condenser (3) being connected to the inlet of the liquid ammonia storage tank (8) via a gas ammonia liquefaction unit.
2. A refrigeration system for liquid carbon dioxide production according to claim 1, characterized in that: The gas-ammonia liquefaction unit comprises at least an ammonia compressor (9) and an evaporative condenser (11); the ammonia compressor (9) is a two-stage ammonia compressor, the gas phase outlet of the second channel of the secondary condenser (3) is connected to the primary compressed gas phase inlet of the ammonia compressor (9), and the gas phase outlet of the second channel of the primary condenser (2) and the primary compressed gas phase outlet of the ammonia compressor (9) are respectively connected to the secondary compressed gas phase inlet of the ammonia compressor (9); The gas phase outlet of the ammonia compressor (9) is connected to the inlet of the liquid ammonia storage tank (8) through the evaporative condenser (11).
3. A refrigeration system for liquid carbon dioxide production according to claim 2, characterized in that: The gas-ammonia liquefaction unit further comprises a primary buffer separation tank (12) and a secondary buffer separation tank (13); The inlet of the primary buffer separation tank (12) is connected to the gas phase outlet of the second channel of the secondary condenser (3), and the gas phase outlet of the primary buffer separation tank (12) is connected to the primary compressed gas phase inlet of the ammonia compressor (9); The inlet of the secondary buffer separation tank (13) is respectively connected to the gas phase outlet of the second channel of the primary condenser (2) and the primary compressed gas phase outlet of the ammonia compressor (9), and the gas phase outlet of the secondary buffer separation tank (13) is connected to the secondary compressed gas phase inlet of the ammonia compressor (9).
4. A refrigeration system for liquid carbon dioxide production according to claim 3, characterized in that: A first valve (14) is provided between the gas phase outlet of the primary buffer separation tank (12) and the primary compressed gas phase inlet of the ammonia compressor (9). A second valve (15) is provided between the gas phase outlet of the second channel of the primary condenser (2) and the inlet of the secondary buffer separation tank (13), a third valve (16) is provided between the primary compressed gas phase outlet of the ammonia compressor (9) and the inlet of the secondary buffer separation tank (13), and a fourth valve (17) is provided between the gas phase outlet of the secondary buffer separation tank (13) and the secondary compressed gas phase inlet of the ammonia compressor (9).
5. A refrigeration system for liquid carbon dioxide production according to claim 2, characterized in that: The gas-ammonia liquefaction unit further comprises a heat exchanger (10) arranged between the ammonia compressor (9) and the evaporative condenser (11). The gas phase outlet of the ammonia compressor (9) is connected to the inlet of the evaporative condenser (11) through the first channel of the heat exchanger (10); The tail gas outlet of the first channel of the secondary condenser (3) is connected to the carbon dioxide tail gas treatment device (18) through the second channel of the heat exchanger (10).
6. A refrigeration system for liquid carbon dioxide production according to claim 1, characterized in that: The inlet end of the carbon dioxide product gas pipeline (1) is connected to the product gas outlet of the distillation tower (5), and the liquid phase outlet of the first channel of the secondary condenser (3) is connected to the reflux port (6) of the distillation tower (5).
7. A refrigeration system for liquid carbon dioxide production according to claim 1, characterized in that: The liquid ammonia storage tank (8) is provided with a liquid ammonia replenishing pipeline (4) with a liquid ammonia valve (7).