WO2023138089A1

WO2023138089A1 - Liquid ammonia double-working-condition refrigerating system and liquid carbon dioxide production equipment

Info

Publication number: WO2023138089A1
Application number: PCT/CN2022/121025
Authority: WO
Inventors: 戚剑威; 潘光万; 黎伟彬; 曾凡超; 郑书艳
Original assignee: 广州市华达石化有限公司
Priority date: 2022-01-24
Filing date: 2022-09-23
Publication date: 2023-07-27
Also published as: CN114485051B; CN114485051A

Abstract

A liquid ammonia double-working-condition refrigerating system and liquid carbon dioxide production equipment (10). The liquid ammonia double-working-condition refrigerating system comprises the following components: a plurality of standard-working-condition ice machines (210); and a plurality of low-temperature working condition ice machines (220). A liquid ammonia circulating device (230) has one interface communicated with a first heat exchanger (111) of a light component removal column (110), and the other interface separately communicated with the standard-working-condition ice machines (210) and the low-temperature working condition ice machines (220); a standard-condition ammonia separation device (240) is communicated with the first heat exchanger (111), and gas ammonia at the top that is separated by the standard-condition ammonia separation device (240) enters the standard-working-condition ice machines (210) to be compressed; a low-temperature ammonia separation device (250) is communicated with the bottom of the standard-condition ammonia separation device (240), and gas ammonia at the top that is separated by the low-temperature ammonia separation device (250) enters the low-temperature working condition ice machines (220) to be compressed; and a supercooling ammonia separation device (260) is communicated with the bottom of the low-temperature ammonia separation device (250), and gas ammonia at the top that is separated by the supercooling ammonia separation device (260) enters the low-temperature working condition ice machines (220) to be compressed. The liquid ammonia double-working-condition refrigerating system can improve the efficiency of the ice machines, and reduce energy consumption.

Description

Liquid ammonia double working condition refrigeration system and liquid carbon dioxide production equipment

This application claims the priority of the Chinese patent application with the application number 202210082523.X and the title of the invention "Liquid Ammonia Dual Working Condition Refrigeration System and Liquid Carbon Dioxide Production Equipment" filed at the China Patent Office on January 24, 2022, the entire contents of which are incorporated in this application by reference.

technical field

The application belongs to the technical field of chemical production equipment, and more specifically relates to a liquid ammonia dual-working-condition refrigeration system and liquid carbon dioxide production equipment.

Background technique

Nowadays, there is more and more demand for high-purity liquid carbon dioxide products in the market, and more and more people pay more and more attention to high-purity liquid carbon dioxide purification devices. Liquid carbon dioxide can often be used to make food additives, and its production process usually includes compression, purification, liquefaction, purification, storage, etc., so that the heavy and light components in carbon dioxide can be removed more thoroughly. In the production process of carbon dioxide, especially in the liquefaction and purification process, liquid ammonia refrigeration under low temperature conditions is required to realize the liquefaction and purification of gaseous carbon dioxide. However, since the ice machine for making liquid ammonia is a device for compressing gas, there will be a phenomenon that the high-pressure outlet material leaks back to the low-pressure inlet. If the pressure difference is higher, the leakage will increase, which will lead to higher energy consumption of the ice machine unit. This also shows that when the liquid ammonia ice machine operates at a lower temperature, the greater the pressure difference between the inlet and outlet of the unit, the worse the efficiency. In this way, when the liquid ammonia ice machine operates under low temperature conditions, the efficiency will be lower and the energy consumption will be higher than that under standard conditions.

technical problem

One of the objectives of the embodiments of the present application is to provide a liquid ammonia dual-working-condition refrigeration system to solve the technical problem of low efficiency and high energy consumption of ice machines in the prior art.

technical solution

In order to solve the above-mentioned technical problems, the technical solution adopted in the embodiment of the present application is:

In the first aspect, a liquid ammonia dual-working-condition refrigeration system is provided, which is used in liquid carbon dioxide production equipment. The liquid carbon dioxide production equipment includes a light removal tower with a first heat exchanger at the bottom, a main cooling device and a top cooling device for cooling liquefied gaseous carbon dioxide, and the liquid ammonia dual-working-condition refrigeration system includes:

A number of ice machines under standard working conditions;

A number of low-temperature ice machines;

A liquid ammonia circulation device, one interface of the liquid ammonia circulation device is connected to the first heat exchanger, and the other interface of the liquid ammonia circulation device is respectively connected to the standard working condition ice machine and the low temperature working condition ice machine;

The standard-condition ammonia separator is connected to the first heat exchanger, and the gaseous ammonia at the top after being separated by the standard-condition ammonia separator enters the standard-condition ice machine for compression;

The low-temperature ammonia separation device communicates with the bottom of the standard-condition ammonia separation device, part of the liquid ammonia at the bottom after being separated by the standard-condition ammonia separation device enters the low-temperature ammonia separation device, and the gas ammonia at the top after being separated by the low-temperature ammonia separation device enters the low-temperature working condition ice machine for compression; and,

The supercooled ammonia separator is connected to the bottom of the low-temperature ammonia separator. Part of the liquid ammonia at the bottom after being separated by the low-temperature ammonia separator enters the supercooled ammonia separator, and the gaseous ammonia at the top after being separated by the cold ammonia separator enters the low-temperature working condition ice machine for compression.

In one embodiment, the main cooling device communicates with the bottom of the standard-condition ammonia separator, and another part of liquid ammonia at the bottom after being separated by the standard-condition ammonia separator enters the main cooling device to vaporize and then returns to the standard-condition ammonia separator.

In one embodiment, the top cooling device communicates with the bottom of the low-temperature ammonia separation device, and another part of liquid ammonia at the bottom after being separated by the low-temperature ammonia separation device enters the top cooling device to vaporize and then returns to the low-temperature ammonia separation device.

In one embodiment, the liquid carbon dioxide production equipment further includes a subcooler, and the subcooler communicates with the bottom of the subcooled ammonia separator, and another part of liquid ammonia at the bottom after being separated by the cold ammonia separator enters the subcooler to vaporize and then returns to the supercooled ammonia separator.

In one embodiment, the liquid ammonia double-working-condition refrigeration system further includes several ammonia evaporative condensers, and both the ice machine under standard working condition and the ice machine under low-temperature working condition are connected to the ammonia evaporative condenser.

In one embodiment, the liquid ammonia double-working-condition refrigeration system further includes an auxiliary ammonia storage, one side of the auxiliary ammonia storage is connected to the liquid ammonia circulation device, and the other side of the auxiliary ammonia storage is connected to the ammonia evaporation condenser.

In one embodiment, the liquid ammonia circulation device is a high-pressure circulation barrel.

In the second aspect, a liquid carbon dioxide production equipment is provided, the liquid carbon dioxide production equipment includes a liquid carbon dioxide purification system and a liquid ammonia double-working-condition refrigeration system as described above; the liquid carbon dioxide purification system is used to purify gaseous carbon dioxide into liquid carbon dioxide, and the liquid ammonia double-work-condition refrigeration system is used to compress gaseous ammonia into liquid ammonia and discharge it into the liquid carbon dioxide purification system to realize the liquefaction of gaseous carbon dioxide.

In one embodiment, the carbon dioxide purification and refining system includes:

Weight-removing column, which is used to feed gaseous carbon dioxide to separate heavy component liquid;

The main cooling device communicates with the top of the weight removal tower, and is used to cool down and liquefy the gaseous carbon dioxide flowing out from the top of the weight removal tower into a mixed fluid containing light components and liquid carbon dioxide;

The first gas-liquid separator communicates with the main cooling device and is used for gas-liquid separation of the mixed fluid;

The top cooling device communicates with the bottom of the deweighting tower, and is used to continue to condense part of the heavy component liquid;

The second gas-liquid separator is communicated with the bottom of the weight-removing tower, and is used for carrying out gas-liquid separation to another part of the heavy component liquid;

The third gas-liquid separator is communicated with the top cooling device, and is used for gas-liquid separation of the heavy component liquid condensed by the top cooling device; and,

The light removal tower communicates with the bottom of the first gas-liquid separator, the bottom of the second gas-liquid separator and the bottom of the third gas-liquid separator respectively.

In one embodiment, the top of the first gas-liquid separator communicates with the top cooling device; the bottom of the first gas-liquid separator also communicates with the deweighting tower.

Beneficial effect

The beneficial effect of the liquid ammonia dual-working-condition refrigeration system provided by this application is that, compared with the existing liquid ammonia production process that only uses low-temperature ice machines, in this embodiment, since the liquid ammonia dual-working-condition refrigeration system adopts the combination of standard working conditions and low-temperature working conditions for step-by-step cooling, it can effectively optimize the liquid ammonia operation process, thereby achieving the purpose of improving the refrigeration efficiency of liquid ammonia and reducing the production energy consumption of liquid carbon dioxide production equipment. It is a more energy-saving and efficient technology.

Description of drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the accompanying drawings that are required in the embodiments or exemplary technical descriptions. Obviously, the accompanying drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, other drawings can also be obtained based on these drawings without creative work.

Fig. 1 is the structural representation of the liquid carbon dioxide production equipment that the embodiment of the present application provides;

Fig. 2 is a partial structural schematic diagram of the liquid carbon dioxide production equipment including the liquid carbon dioxide purification system provided by the embodiment of the present application;

Fig. 3 is a partial structural schematic diagram of the liquid ammonia production equipment provided in the embodiment of the present application, including the liquid ammonia double-working-condition refrigeration system.

Explanation of reference numbers:

10. Liquid carbon dioxide production equipment;

110. Light removal tower; 111. First heat exchanger; 120. Weight removal tower; 130. Main cooling device; 140. Top cooling device; 150. Subcooler; 160. First gas-liquid separator; 170. Second gas-liquid separator; 180. Third gas-liquid separator;

210. Standard working condition ice machine; 220. Low temperature working condition ice machine; 230. Liquid ammonia circulation device; 240. Standard condition ammonia separation device; 250. Low temperature ammonia separation device; 260. Supercooled ammonia separation device; 270. Ammonia evaporation condenser;

310, LICA; 320, valve group.

Embodiments of the present invention

In order to make the purpose, technical solution and advantages of the present application clearer, the present application will be further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described here are only used to explain the present invention, not to limit the present application.

It should be noted that when a component is referred to as being “fixed on” or “disposed on” another component, it may be directly on the other component or indirectly on the other component. When an element is referred to as being "connected to" another element, it can be directly or indirectly connected to the other element. The orientations or positional relationships indicated by the terms "upper", "lower", "left", "right", etc. are based on the orientations or positional relationships shown in the drawings, and are only for the convenience of description, rather than indicating or implying that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be construed as limiting the present application. For those of ordinary skill in the art, the specific meanings of the above terms can be understood according to specific situations. The terms "first" and "second" are used for descriptive purposes only, and should not be understood as indicating or implying relative importance or implicitly specifying the quantity of technical features. "Plurality" means two or more, unless otherwise clearly and specifically defined.

In order to illustrate the technical solutions described in this application, the following will be described in detail in conjunction with specific drawings and embodiments.

This application proposes a liquid ammonia dual-working-condition refrigeration system.

Please refer to Fig. 1 to Fig. 3, in one embodiment, the liquid ammonia double working condition refrigeration system is used in the liquid carbon dioxide production equipment 10, the liquid carbon dioxide production equipment 10 includes the light removal tower 110 with the first heat exchanger 111 at the bottom, the main cooling device 130 and the top cooling device 140 for cooling the liquefied gaseous carbon dioxide. Specifically, this liquid ammonia double-working-condition refrigeration system includes several ice machines 210 under standard working conditions, several ice machines 220 under low-temperature working conditions, a liquid ammonia circulation device 230, a standard-condition ammonia separation device 240, a low-temperature ammonia separation device 250, and a supercooled ammonia separation device 260. Wherein, one interface of the liquid ammonia circulation device 230 is communicated with the first heat exchanger 111, and the other interface of the liquid ammonia circulation device 230 is communicated with the ice machine 210 of the standard working condition and the ice machine 220 of the low temperature working condition respectively; The liquid ammonia at the bottom after separation by the sub-device 240 enters the low-temperature ammonia separation device 250, and the gaseous ammonia at the top after being separated by the low-temperature ammonia separation device 250 enters the ice machine 220 under low-temperature conditions for compression;

It should be noted here that the liquid carbon dioxide production equipment 10 in this embodiment is mainly used to purify and liquefy gaseous carbon dioxide containing impurities into high-purity liquid carbon dioxide, which can be used to manufacture food additives and the like. Here, the liquid carbon dioxide production equipment 10 mainly includes a liquid carbon dioxide purification system and a liquid ammonia dual-working-condition refrigeration system. In the liquid ammonia dual-working-condition refrigeration system, the temperature of the low-temperature working condition applicable to the low-temperature working condition ice machine 220 is usually -30°C, and the standard working condition temperature applicable to the standard working condition ice machine 210 is usually -18°C. Of course, in other embodiments, the temperature of the low-temperature working condition and the standard working condition can also be adjusted according to actual needs, and there is no special limitation here.

Based on this structural design, compared with the existing liquid carbon dioxide production process that only uses low-temperature ice machines, in this embodiment, since the liquid ammonia dual-condition refrigeration system adopts the combination of standard operation and low-temperature operation to perform step-by-step cooling, the operation process of liquid ammonia can be effectively optimized, thereby achieving the purpose of improving the refrigeration efficiency of liquid ammonia and reducing the production energy consumption of liquid carbon dioxide production equipment 10. It is a more energy-saving and efficient technology.

Please refer to Fig. 1 and Fig. 2, specifically in the present embodiment, the main cooling device 130 is communicated with the bottom of the standard-condition ammonia separating device 240, and another part of liquid ammonia at the bottom after being separated by the standard-condition ammonia separating device 240 enters the main cooling device 130 for vaporization and then returns to the standard-condition ammonia separating device 240. It can be understood that when the liquid ammonia in the liquid ammonia circulation device 230 passes through the first heat exchanger 111 at the bottom of the light removal tower 110 to realize its cooling function, it will enter the standard-condition ammonia separation device 240 from the bottom of the light removal tower 110 to realize gas-liquid separation, and then gas ammonia flows out from the top of the standard-condition ammonia separation device 240 until it enters the standard-condition ice machine 210 to realize compression. A part of the liquid ammonia at the bottom of the standard-condition ammonia separation device 240 will continue to flow into the low-temperature ammonia separation device 250 for further The other part of the liquid ammonia enters the main cooling device 130 to realize vaporization, and then returns to the standard-condition ammonia separator 240 to realize the gas-liquid separation of the cycle. In this way, the refrigeration efficiency of liquid ammonia can be further improved. Here, a LICA310 (level indication control alarm) is also provided on the standard-condition ammonia separation device 240, and a valve group 320 matching the LICA310 is also provided on the pipeline connecting the light removal tower 110 and the standard-condition ammonia separation device 240.

Further, as shown in Figures 1 and 2, in this embodiment, the liquid carbon dioxide production equipment 10 also includes a top cooling device 140, and the top cooling device 140 communicates with the bottom of the low-temperature ammonia separation device 250, and another part of liquid ammonia at the bottom after being separated by the low-temperature ammonia separation device 250 enters the top cooling device 140 for vaporization and then returns to the low-temperature ammonia separation device 250. Similarly, a LICA310 is also provided on the low-temperature ammonia separator 250 , and a matching valve group 320 is provided on the pipeline connecting the standard-condition ammonia separator 240 and the low-temperature ammonia separator 250 . It can be understood that when part of the liquid ammonia at the bottom of the ammonia separation device 240 under the standard condition enters the low-temperature ammonia separation device 250 to realize gas-liquid separation, the gaseous ammonia at the upper part of the device flows out until it enters the ice machine 220 under low-temperature working condition to realize compression, and part of the liquid ammonia at the bottom of the low-temperature ammonia separation device 250 will continue to flow into the supercooled ammonia separation device 260 for further gas-liquid separation, and the other part of the liquid ammonia enters the top cooling device 140 to realize vaporization, and then flows back to the standard-condition ammonia separation device 240 to realize circulation. The gas-liquid separation, so that the refrigeration efficiency of liquid ammonia can be further improved.

1 and 2, further, in this embodiment, the liquid carbon dioxide production equipment 10 also includes a subcooler 150 heat exchange device, the subcooler 150 heat exchange device communicates with the bottom of the subcooled ammonia separation device 260, and another part of the liquid ammonia at the bottom after being separated by the cold ammonia separation device 260 enters the subcooler 150 heat exchange device to vaporize and then returns to the supercooled ammonia separation device 260, so that the refrigeration efficiency of the liquid ammonia can be further improved. Of course, a LICA310 is also provided on the heat exchange device of the subcooler 150 and a matching valve group 320 is provided on the corresponding pipeline. It should be noted here that there are two sources of ammonia gas entering the ice machine 220 under low-temperature conditions, one of which is the upper part of the low-temperature ammonia separation device 250 and the other is the upper part of the supercooled ammonia separation device 260.

In addition, please refer to FIG. 1 and FIG. 3 , the liquid ammonia double working condition refrigeration system also includes several ammonia evaporative condensers 270 , and the standard working condition ice machine 210 and the low temperature working condition ice machine 220 are both connected to the ammonia evaporative condenser 270 . Since the condensation temperature of ammonia increases with the increase of pressure, when the pressure increases to 1.6MPa, the condensation temperature of ammonia is 40°C, which is higher than the temperature of general cooling water, so it can be cooled with normal temperature water at 25-35°C to liquefy it. The specific process is as follows: firstly, the ammonia gas is compressed by the ice machine 210 under the standard working condition and the ice machine 220 under the low temperature working condition, and enters the ammonia evaporative condenser 270, and the heat released by the ammonia gas is taken away by the cooling water, so that the ammonia gas is condensed into liquid ammonia. Then, the liquid ammonia passing through the throttling valve will be lowered from the condensing pressure to the evaporation pressure; the throttling and expanded ammonia evaporates in the ammonia evaporating condenser 270 to absorb the heat taken away by the cooling water, and the liquid ammonia changes into gas ammonia and is sent to the standard working condition ice machine 2 10 and the inlet of the ice machine 220 in low-temperature working conditions, so that a refrigeration cycle is formed, and the cycle continues to run, and the temperature of ammonia will continue to decrease to reach the required temperature.

Here, in order to improve the efficiency of the refrigeration system, the number of ammonia evaporative condensers 270 is preferably multiple, and the number of ice machines 210 under standard working conditions and ice machines 220 under low temperature working conditions is also preferably multiple. For example, in this embodiment, there are specifically three ammonia evaporative condensers 270 , two ice machines 210 under standard operating conditions, and three ice machines 220 under low-temperature operating conditions. Of course, in other embodiments, the specific numbers of the ammonia evaporative condenser 270 , the ice machine 210 under the standard working condition and the ice machine 220 under the low temperature working condition can also be set according to actual design requirements, and there is no special limitation here.

Further, please refer to FIG. 3 , in this embodiment, the liquid ammonia double-working-condition refrigeration system further includes an auxiliary ammonia storage device 280, one side port of the auxiliary ammonia storage device 280 communicates with the liquid ammonia circulation device 230, and the other side port of the auxiliary ammonia storage device 280 communicates with the ammonia evaporation condenser 270. Here, the auxiliary ammonia storage 280 mainly plays the role of transfer and temporary storage. Wherein, since there are specifically three ammonia evaporative condensers 270 , three ports are correspondingly provided on one side of the auxiliary ammonia storage 280 to respectively connect the three ammonia evaporative condensers 270 .

Please refer to FIG. 1 and FIG. 2 , in this embodiment, the liquid ammonia circulation device 230 is specifically a high-pressure circulation barrel. The liquid ammonia circulation device 230 is used to store liquid ammonia and transport the liquid ammonia to the first heat exchanger 111 at the bottom of the light removal tower 110, thereby starting the circulation of liquid ammonia in the liquid carbon dioxide purification system, ensuring that gaseous carbon dioxide can be successfully purified and condensed into high-purity liquid carbon dioxide. Certainly, in other embodiments, the liquid ammonia circulation device 230 may also be other devices capable of realizing liquid ammonia circulation operation, but in this embodiment, the high-pressure circulation barrel has the advantage of being simpler and more efficient.

Here, based on the foregoing, the operation process of the liquid ammonia double-working mode refrigeration system in this embodiment will be described in detail below: first, the liquid ammonia in the liquid ammonia circulation device 230, that is, the liquid ammonia in the high-pressure circulation barrel, enters the first heat exchanger 111 located at the bottom of the light removal tower 110; Part of the liquid ammonia at the bottom of the device 240 enters the low-temperature ammonia separation device 250, and the other part enters the main cooling device 130 to realize vaporization and heat absorption, and then returns to the standard-condition ammonia separation device 240; the liquid ammonia entering the low-temperature ammonia separation device 250 undergoes further gas-liquid separation, and the gaseous ammonia at the top is transported to the low-temperature working condition ice machine 220 for compression, and the liquid ammonia at the bottom is divided into two parts. Then, it flows back to the low-temperature ammonia separation device 250; the liquefied ammonia entering the supercooled ammonia separation device 260 further realizes gas-liquid separation, and the gaseous ammonia at the top is also transported to the ice machine 220 under low-temperature working conditions for compression, that is, the gas ammonia at the top of the supercooled ammonia separating device 260 and the low-temperature ammonia separating device 250 enters the low-temperature working condition ice machine 220 together for compression. Cold ammonia separation device 260. Then, the gas ammonia compressed by the standard working condition ice machine 210 and the low temperature working condition ice machine 220 enters the ammonia evaporation condenser 270 to be liquefied, then flows back to the auxiliary ammonia storage 280, and finally flows back to the liquid ammonia circulation device 230 for the next cycle.

The present application also proposes a liquid carbon dioxide production equipment 10, wherein the liquid carbon dioxide purification system in the liquid carbon dioxide production equipment 10 is used to purify gaseous carbon dioxide into liquid carbon dioxide, and the liquid ammonia double-working mode refrigeration system is used to compress gaseous ammonia into liquid ammonia and discharge it into the liquid carbon dioxide purification system to realize the liquefaction of gaseous carbon dioxide.

Please refer to FIG. 1 and FIG. 2 , in this embodiment, the carbon dioxide purification and refining system specifically includes a weight removal tower 120 , a main cooling device 130 , a first gas-liquid separator 160 , a top cooling device 140 , a second gas-liquid separator 170 , a third gas-liquid separator 180 and a light removal tower 110 . Wherein, the deweighting tower 120 is used for supplying gaseous carbon dioxide to enter to separate the heavy component liquid; the main cooling device 130 communicates with the top of the deweighting tower 120, and is used to cool and liquefy the gaseous carbon dioxide flowing out from the top of the deweighting tower 120 into a mixed fluid containing light components and liquid carbon dioxide; the first gas-liquid separator 160 communicates with the main cooling device 130, and is used for performing gas-liquid separation on the mixed fluid; the top cooling device 140 communicates with the bottom of the deweighting tower 120, for continuing to condense part of the heavy component liquid The second gas-liquid separator 170 is communicated with the bottom of the weight removal tower 120, and is used for carrying out gas-liquid separation to another part of the heavy component liquid; the third gas-liquid separator 180 is communicated with the top cooling device 140, and is used for carrying out gas-liquid separation of the heavy component liquid condensed through the top cooling device 140;

Further, as shown in FIG. 2 , in this embodiment, the top of the first gas-liquid separator 160 communicates with the top cooling device 140 , so that the light components at the top of the first gas-liquid separator 160 can enter the top cooling device 140 for further condensation. In addition, the bottom of the first gas-liquid separator 160 is also connected to the weight removal tower 120, so that part of the liquid at the bottom of the first gas-liquid separator 160 will flow back into the weight removal tower 120, while the other part will enter the weight removal tower 110, which is conducive to improving the accuracy of liquid carbon dioxide and making it more efficient and energy-saving.

Here, based on the aforementioned content, the operation process of the liquid ammonia double-working mode refrigeration system in this embodiment will be described in detail below: first, gaseous carbon dioxide enters the weight removal tower 120 from the lower part of the weight removal tower 120, and after heat exchange in the weight removal tower 120, the gaseous carbon dioxide at the top of the weight removal tower 120 enters the main cooling device 130 for cooling and liquefaction, and the heavy component liquid at the bottom of the weight removal tower 120 will be divided into two parts and discharged to the top cooling device 140 and the second gas-liquid separator 170; After the heavy component liquid is separated by the second gas-liquid separator 170, part of the heavy component at the bottom will be discharged to other processes, and the gaseous carbon dioxide at the top will also be discharged to other processes; the liquid carbon dioxide after cooling down and liquefied in the main cooling device 130 actually contains a certain amount of light components, which is a mixed fluid, and this mixed fluid will enter the first gas-liquid separator 160 for gas-liquid separation. Part of the heavy component liquid at the bottom of the deweighting tower 120 of the top cooling device 140 is condensed in the top cooling device 140 together; the condensed liquid enters the third gas-liquid separator 180 for further gas-liquid separation, and the non-condensable gas light components at the top will be discharged to the next process.

The above are only optional embodiments of the application, and are not intended to limit the application. For those skilled in the art, various modifications and changes may occur in this application. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present application shall be included within the scope of the claims of the present application.

Claims

A liquid ammonia double-working-condition refrigeration system is used in liquid carbon dioxide production equipment, and the liquid carbon dioxide production equipment includes a light removal tower with a first heat exchanger at the bottom, a main cooling device and a top cooling device for cooling liquefied gaseous carbon dioxide, and is characterized in that the liquid ammonia dual-working-condition refrigeration system includes:

A number of ice machines under standard working conditions;

A number of low-temperature ice machines;

A liquid ammonia circulation device, one interface of the liquid ammonia circulation device communicates with the first heat exchanger, and the other interface of the liquid ammonia circulation device communicates with the standard working condition ice machine and the low temperature working condition ice machine respectively;

The standard-condition ammonia separator is communicated with the first heat exchanger, and the gaseous ammonia at the top after being separated by the standard-condition ammonia separator enters the standard-condition ice machine for compression;

The low-temperature ammonia separation device communicates with the bottom of the standard-condition ammonia separation device, part of the liquefied ammonia at the bottom after being separated by the standard-condition ammonia separation device enters the low-temperature ammonia separation device, and the gas ammonia at the top after being separated by the low-temperature ammonia separation device enters the low-temperature working condition ice machine for compression; and,

The supercooled ammonia separation device communicates with the bottom of the low-temperature ammonia separation device, part of the liquefied ammonia at the bottom after being separated by the low-temperature ammonia separation device enters the supercooled ammonia separation device, and the gas ammonia at the top after being separated by the supercooled ammonia separation device enters the low-temperature working condition ice machine for compression.
The liquid ammonia dual-working-condition refrigeration system according to claim 1, wherein the main cooling device communicates with the bottom of the standard-condition ammonia separation device, and another part of the liquid ammonia at the bottom after being separated by the standard-condition ammonia separation device enters the main cooling device to vaporize and then flows back to the standard-condition ammonia separation device.
The refrigeration system with dual working conditions for liquid ammonia according to claim 1, wherein the top cooling device communicates with the bottom of the low-temperature ammonia separation device, and another part of liquid ammonia at the bottom after being separated by the low-temperature ammonia separation device enters the top cooling device to vaporize and then returns to the low-temperature ammonia separation device.
The liquid ammonia dual-working-condition refrigeration system according to claim 1, wherein the liquid carbon dioxide production equipment further comprises a subcooler, the subcooler communicates with the bottom of the supercooled ammonia separation device, and another part of the liquid ammonia at the bottom after being separated by the supercooled ammonia separation device enters the supercooler to vaporize and then flows back to the supercooled ammonia separation device.
The liquid ammonia dual-working-condition refrigeration system according to any one of claims 1 to 4, characterized in that the liquid ammonia dual-working-condition refrigeration system further includes several ammonia evaporative condensers, and both the standard-working-condition ice machine and the low-temperature working-condition ice machine are connected to the ammonia evaporating condensers.
The liquid ammonia dual-working-condition refrigeration system according to claim 5, wherein the liquid ammonia dual-working-condition refrigeration system further includes an auxiliary ammonia storage device, one side interface of the auxiliary ammonia storage device communicates with the liquid ammonia circulation device, and the other side interface of the auxiliary ammonia storage device communicates with the ammonia evaporation condenser.
The liquid ammonia dual-working-condition refrigeration system according to claim 1, wherein the liquid ammonia circulation device is a high-pressure circulation barrel.
A liquid carbon dioxide production equipment, characterized in that it comprises a liquid carbon dioxide purification system and a liquid ammonia double-working-condition refrigeration system according to any one of claims 1 to 7; the liquid carbon dioxide purification system is used to purify gaseous carbon dioxide into liquid carbon dioxide, and the liquid ammonia double-work-condition refrigeration system is used to compress gaseous ammonia into liquid ammonia and discharge it into the liquid carbon dioxide purification system to realize the liquefaction of gaseous carbon dioxide.
The liquid carbon dioxide production equipment according to claim 8, wherein the carbon dioxide purification and refining system comprises:

Weight-removing column, which is used to feed gaseous carbon dioxide to separate heavy component liquid;

The main cooling device is connected with the top of the weight removal tower, and is used to cool down and liquefy the gaseous carbon dioxide flowing out from the top of the weight removal tower into a mixed fluid containing light components and liquid carbon dioxide;

a first gas-liquid separator, communicated with the main cooling device, and used for gas-liquid separation of the mixed fluid;

A top cooling device, communicated with the bottom of the deweighting tower, for continuing to condense part of the heavy component liquid;

The second gas-liquid separator is communicated with the bottom of the deweighting tower, and is used for gas-liquid separation of another part of the heavy component liquid;

The third gas-liquid separator is communicated with the top cooling device, and is used for gas-liquid separation of the heavy component liquid condensed by the top cooling device; and,

The light removal tower communicates with the bottom of the first gas-liquid separator, the bottom of the second gas-liquid separator and the bottom of the third gas-liquid separator respectively.
The liquid carbon dioxide production equipment according to claim 9, characterized in that, the top of the first gas-liquid separator communicates with the top cooling device; the bottom of the first gas-liquid separator also communicates with the weight removal tower.