Liquid carbon dioxide cold energy recovery system

Abstract

The utility model discloses a kind of liquid carbon dioxide cold energy recovery systems, including storage tank, vaporizer and heat exchanger;Vaporizer includes shell, and the storage cavity for accommodating refrigerant medium in shell, shell is connected with the vaporization passage passing through storage cavity, and the feeding end of vaporization passage is connected in storage tank;Refrigerant inlet and refrigerant outlet are equipped on storage cavity, refrigerant inlet is connected for storing refrigerant medium refrigerant container, and low-temperature pump is connected between refrigerant container and refrigerant inlet;Refrigerant outlet is communicated in heat exchanger and refrigerant container, and heat transfer medium passes through heat exchanger.Compared with prior art, the utility model integrates liquid carbon dioxide vaporization device and cold energy recovery device together, can effectively pass the cold quantity generated when liquid carbon dioxide vaporization to heat transfer medium for downstream use in the form of heat exchange, fully utilizes the cold quantity generated by liquid carbon dioxide vaporization, saves the energy consumption of refrigeration system, saves energy, reduces cost.

Description

Technical Field

[0001] This utility model relates to the field of cold energy recovery technology, and in particular to a liquid carbon dioxide cold energy recovery system. Background Technology

[0002] Due to its high saturated vapor pressure and weak intermolecular forces, liquid carbon dioxide vaporizes much faster than conventional liquids. This rapid vaporization quickly absorbs heat from the surrounding environment. If the vaporization volume is large, the temperature of the remaining liquid carbon dioxide may drop sharply, or even freeze directly into solid carbon dioxide, forming a continuous phase transition from liquid to solid to gas. When the CO2 temperature is below the triple point (-56.6℃, 517kPa), liquid CO2 will freeze directly into solid dry ice, causing blockages in pipes and heat exchangers, affecting the normal operation of the system. Dry ice blockage can lead to a sudden increase in local pressure, and even serious accidents such as pipe rupture. However, current patents on cryogenic liquid vaporization and commercially available equipment do not adequately address the pipe blockages and drastic pressure changes caused by the liquid-to-solid phase transition. They simply use a large amount of heat for heating, which not only complicates the process but also results in a double waste of the system's own cooling energy and the energy of the external heating device.

[0003] Therefore, there is an urgent need for a liquid carbon dioxide cold energy recovery system. Utility Model Content

[0004] The purpose of this invention is to provide a liquid carbon dioxide cold energy recovery system. This system integrates a liquid carbon dioxide vaporization device with a cold energy recovery device, which can effectively transfer the cold energy generated during the vaporization of liquid carbon dioxide to the refrigerant through heat exchange for downstream use. It makes full use of the cold energy generated by the vaporization of liquid carbon dioxide, saves energy consumption of the refrigeration system, saves energy, and reduces costs, thereby solving the problems mentioned in the background art.

[0005] To achieve the above objectives, this utility model provides the following technical solution:

[0006] A liquid carbon dioxide cold energy recovery system includes a storage tank for storing liquid carbon dioxide, a vaporizer for cryogenic vaporization, and a heat exchanger for cold energy recovery. The vaporizer includes a shell, inside which is a storage cavity for containing a refrigerant. A vaporization channel is connected inside the shell, passing through the storage cavity, and the inlet end of the vaporization channel is connected to the storage tank. The storage cavity is provided with a refrigerant inlet and a refrigerant outlet. The refrigerant inlet is connected to a refrigerant container for storing the refrigerant, and a cryogenic pump is connected between the refrigerant container and the refrigerant inlet. The refrigerant outlet is connected to the heat exchanger and the refrigerant container, and the refrigerant passes through the heat exchanger.

[0007] A further improvement of this utility model is that the vaporizers are multiple sets arranged in parallel, the storage tank is connected to the inlet end of the vaporization channel through the first pipe, and the vaporization channel inside the shell has a spiral structure, with a ball valve c connected to the first pipe.

[0008] A further improvement of this utility model is that the outlet end of the vaporization channel is connected to a second pipe, which leads to downstream equipment, and a flow meter, a pressure transmitter, a temperature transmitter a, and a ball valve a are connected to the second pipe.

[0009] A further improvement of this utility model is that a third pipe is connected to the second pipe, the third pipe extends to a safe and open high-altitude area to release gaseous carbon dioxide, and a safety release valve is connected to the third pipe.

[0010] A further improvement of this utility model is that the refrigerant inlet is located at the bottom of the storage cavity, the refrigerant outlet is located above the storage cavity, the refrigerant inlet is connected to the refrigerant container through a fourth pipe, and the cryogenic pump is connected to the fourth pipe.

[0011] A further improvement of this utility model is that the heat exchanger is a plate heat exchanger, the refrigerant outlet is connected to the first channel of the heat exchanger through a fifth pipe, and the outlet of the first channel is connected to the refrigerant container through a sixth pipe. A temperature transmitter b and a gate valve a are connected to the fifth pipe, and a gate valve b and a temperature transmitter c are connected to the sixth pipe.

[0012] A further improvement of this utility model is that a seventh pipe is connected between the fifth pipe and the sixth pipe, and a ball valve b is connected to the seventh pipe.

[0013] A further improvement of this utility model is that the feed end of the second channel of the heat exchanger is connected to an eighth pipe, and the discharge end is connected to a ninth pipe. The refrigerant enters the heat exchanger through the eighth pipe and is discharged from the ninth pipe to be transported to the equipment that needs to be cooled.

[0014] A further improvement of this invention is that the cooling medium is ethylene glycol, propylene glycol, alcohol, or a mixture of ethylene glycol and propylene glycol.

[0015] The beneficial effects of this utility model are:

[0016] This utility model discloses a liquid carbon dioxide cold energy recovery system that integrates a liquid carbon dioxide vaporization device with a cold energy recovery device. It can effectively transfer the cold energy generated during the vaporization of liquid carbon dioxide to the refrigerant through heat exchange for downstream use. This fully utilizes the cold energy generated by the vaporization of liquid carbon dioxide, saves energy consumption of the refrigeration system, conserves energy, and reduces costs.

[0017] This utility model's liquid carbon dioxide cold energy recovery system effectively solves the problem of easy ice blockage in pipelines and improves the stability of liquid carbon dioxide vaporization.

[0018] This utility model's liquid carbon dioxide cold energy recovery system avoids direct contact between carbon dioxide and the material being cooled, reducing the risk of leakage. Furthermore, the low freezing point of the cold medium is suitable for low-temperature scenarios, and the high heat of vaporization of carbon dioxide enables efficient heat exchange, which aligns with the trend of environmentally friendly refrigeration.

[0019] This utility model discloses a liquid carbon dioxide cold energy recovery system that can recover cold energy at low temperatures using room-temperature refrigerant. Apart from the power consumption of the fluid circulation pump, no additional heat energy replenishment is required. It can precisely control the amount of vaporized liquid, continuously providing downstream users with a precise volume of vaporized liquid. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the overall design of this utility model.

[0021] Figure 2 This is a schematic diagram of the vaporizer of this utility model.

[0022] In the diagram: 1-Storage tank, 2-Vaporizer, 201-Shell, 202-Vaporization channel, 203-Refrigerant inlet, 204-Refrigerant outlet, 3-Heat exchanger, 301-First channel, 302-Second channel, 4-Cryogenic pump, 5-Refrigerant container, 6-First pipeline, 7-Second pipeline, 8-Flow meter, 9-Pressure transmitter, 10-Temperature transmitter a, 11-Ball valve a, 12-Third pipeline, 13-Safety vent valve, 14-Fifth pipeline, 15-Sixth pipeline, 16-Temperature transmitter b, 17-Gate valve a, 18-Gate valve b, 19-Temperature transmitter c, 20-Seventh pipeline, 21-Ball valve b, 22-Eighth pipeline, 23-Ninth pipeline, 24-Ball valve c. Detailed Implementation

[0023] The present invention will be further explained below with reference to the accompanying drawings and specific embodiments.

[0024] Example 1: As Figures 1-2As shown, a liquid carbon dioxide cold energy recovery system includes a storage tank 1 for storing liquid carbon dioxide, a vaporizer 2 for cryogenic vaporization, and a heat exchanger 3 for cold energy recovery. The vaporizer 2 includes a shell 201, inside which is a storage cavity for containing a refrigerant. A vaporization channel 202 is connected inside the shell 201, passing through the storage cavity. The inlet end of the vaporization channel 202 is connected to the storage tank 1. The storage cavity is provided with a refrigerant inlet 203 and a refrigerant outlet 204. The refrigerant inlet 203 is connected to a refrigerant container 5 for storing the refrigerant, and a cryogenic pump 4 is connected between the refrigerant container 5 and the refrigerant inlet 203. The refrigerant outlet 204 is connected to the heat exchanger 3 and the refrigerant container 5, and the refrigerant passes through the heat exchanger 3.

[0025] The vaporizers 2 are multiple sets arranged in parallel. The storage tank 1 is connected to the inlet end of the vaporization channel 202 through the first pipe 301. The vaporization channel 202 inside the shell 201 has a spiral structure. A ball valve c24 is connected to the first pipe 6.

[0026] The outlet end of the vaporization channel 202 is connected to a second pipe 302, which leads to downstream equipment. A flow meter 8, a pressure transmitter 9, a temperature transmitter a10, and a ball valve a11 are connected to the second pipe 302.

[0027] The second pipe 302 is connected to the third pipe 12, which extends to a safe and open area at high altitude to release gaseous carbon dioxide. The third pipe 12 is connected to a safety release valve 13.

[0028] The refrigerant inlet 203 is located at the bottom of the storage chamber, and the refrigerant outlet 204 is located above the storage chamber. The refrigerant inlet 203 is connected to the refrigerant container 5 through the fourth pipe, and the cryogenic pump 4 is connected to the fourth pipe.

[0029] The heat exchanger 3 is a plate heat exchanger 3. The refrigerant outlet 204 is connected to the first channel 6 of the heat exchanger 3 through the fifth pipe 14, and the outlet of the first channel 6 is connected to the refrigerant container 5 through the sixth pipe 15. The fifth pipe 14 is connected to the temperature transmitter b16 and the gate valve a17, and the sixth pipe 15 is connected to the gate valve b18 and the temperature transmitter c19.

[0030] A seventh pipe 20 is connected between the fifth pipe 14 and the sixth pipe 15, and a ball valve b21 is connected to the seventh pipe 20.

[0031] The feed end of the second channel 7 of the heat exchanger 3 is connected to the eighth pipe 22, and the discharge end is connected to the ninth pipe 23. The refrigerant enters the heat exchanger 3 through the eighth pipe 22 and is discharged from the ninth pipe 23 to be transported to the equipment that needs to be cooled.

[0032] In this embodiment, the cooling medium is a mixture of ethylene glycol and propylene glycol.

[0033] The working mechanism of this invention utilizes the rapid vaporization of liquid carbon dioxide upon pressure reduction, leading to a sharp drop in ambient temperature. A low-temperature circulating refrigerant is used to exchange this cooling energy with heat. The low-temperature refrigerant provides heat to the environment where the liquid carbon dioxide vaporizes, while simultaneously carrying away the cooling energy.

[0034] Based on the above principle, a microporous vaporization channel 202 with controlled flow rate is set inside the vaporizer 2. The pressure on the liquid carbon dioxide side is basically the same as the pressure in the liquid carbon dioxide storage tank 1. On the vaporization side, the pressure is controlled between 1 and 0.5 MPa according to the required amount of vaporized carbon dioxide gas. After passing through the micropores, the liquid carbon dioxide rapidly vaporizes due to the pressure reduction, absorbing a large amount of heat. The circulating refrigerant provides heat to the vaporization environment of the liquid carbon dioxide, carrying away its heat. The cooled refrigerant then exchanges heat with the fluid requiring cooling through the heat exchanger 3, thus increasing its temperature.

[0035] This cycle continues, recovering the cold energy at room temperature.

[0036] Liquid carbon dioxide in storage tank 1, with an initial temperature of -26℃ and a pressure of 1.5~2.5MPa, enters vaporizer 2 under its own pressure. Vaporizer 2 is composed of multiple sets of low-temperature vaporizers 2 connected in parallel with anti-dry ice blockage devices. The heat exchange temperature during vaporization is -15~-10℃. During the heat exchange process, the liquid carbon dioxide gradually vaporizes. Due to its high boiling point and low initial temperature, the cold medium only releases sensible heat during the heat exchange, transferring heat to the carbon dioxide. After transferring heat, its own temperature gradually decreases to near the outlet temperature of the carbon dioxide. The cold medium then transfers heat to the liquid carbon dioxide. The vaporized carbon dioxide enters the downstream user through the outlet flow meter 8 and the transmitter, relying on the pressure of 0.5~1MPa generated by the expansion of the vaporized gas.

[0037] After cooling, the cold medium enters the heat exchanger 3, which is a conventional plate heat exchanger 3. The cold medium exchanges heat with the refrigerant to produce a low-temperature refrigerant, which is then transported to the scene that needs cooling, such as industrial equipment cooling or central air conditioning heat exchange fluid, to complete the cold energy transfer and reuse.

[0038] The core of this heat exchange process is that the latent heat of vaporization of liquid carbon dioxide dominates the heat exchange, while the sensible heat of the cold medium assists in the heat release. In practical applications, the phase change of carbon dioxide can be controlled to prevent dry ice blockage, and the flow of the cold medium can be effectively optimized to improve heat transfer efficiency. At the same time, because the liquid carbon dioxide vaporization device is integrated with the cold energy recovery device, the cold energy generated during the vaporization of liquid carbon dioxide can be effectively transferred to the refrigerant through heat exchange for downstream use, making full use of the cold energy generated by the vaporization of liquid carbon dioxide and saving energy consumption of the refrigeration system.

[0039] The heat required for the vaporization of one ton of liquid carbon dioxide: The latent heat of vaporization of liquid CO2 is approximately 348 kJ / kg, and the required electrical energy is approximately 96.7 kWh. Total heat = latent heat of vaporization × total heat by mass = 348 kJ / kg × 1000 kg = 348000 kJ. Converted to electrical energy units: 1 kW•h = 3600 kJ, therefore 348000 ÷ 3600 ≈ 96.7 kW•h.

[0040] The energy saved is as follows: the heat of sublimation of dry ice is about 573 kJ / kg, and the heat required for the sublimation of each ton of dry ice is 573 kJ / kg × 1000 kg = 573000 kJ, which is equivalent to about 159 kW•h of electricity; at the same time, the use of heating devices is avoided, reducing system complexity and operation and maintenance costs, and has significant economic and environmental advantages.

[0041] The flow rate can be precisely controlled, with the required output flow rate within ±1%.

[0042] Economic benefits: Calculate the cold energy released from 1 ton of carbon dioxide. Convert this into electricity and generate economic benefits.

[0043] Environmental Benefits: The above calculations translate to carbon emission reduction. This can achieve a significant reduction in carbon emissions; recovering 1 ton of liquid carbon dioxide cold energy is equivalent to reducing standard coal consumption by approximately 0.12 tons, which translates to a reduction of approximately 0.3 tons of carbon dioxide emissions. This technology effectively improves energy efficiency, reducing the power consumption of the refrigeration system by more than 15%, demonstrating good environmental benefits and promotional value.

[0044] The above embodiments are only for illustrating the technical concept and features of this utility model, and are intended to enable those skilled in the art to understand the content of this utility model and implement it accordingly. They should not be construed as limiting the scope of protection of this utility model. All equivalent transformations or modifications made in accordance with the spirit and essence of this utility model should be included within the scope of protection of this utility model.

Claims

1. A liquid carbon dioxide cold energy recovery system, characterized in that: The system includes a storage tank (1) for storing liquid carbon dioxide, a vaporizer (2) for cryogenic vaporization, and a heat exchanger (3) for cold energy recovery. The vaporizer (2) includes a shell (201), which contains a storage cavity for holding a cold medium. A vaporization channel (202) is connected inside the shell (201) and passes through the storage cavity. The inlet end of the vaporization channel (202) is connected to the storage tank (1). The storage cavity is provided with a cold medium inlet (203) and a cold medium outlet (204). The cold medium inlet (203) is connected to a cold medium container (5) for storing the cold medium, and a cryogenic pump (4) is connected between the cold medium container (5) and the cold medium inlet (203). The cold medium outlet (204) is connected to the heat exchanger (3) and the cold medium container (5), and the refrigerant passes through the heat exchanger (3).

2. The liquid carbon dioxide cold energy recovery system as described in claim 1, characterized in that: The vaporizer (2) consists of multiple sets arranged in parallel. The storage tank (1) is connected to the feed end of the vaporization channel (202) through the first pipe (6). The vaporization channel (202) inside the shell (201) has a spiral structure. A ball valve c (24) is connected to the first pipe (6).

3. A liquid carbon dioxide cold energy recovery system as described in claim 1 or 2, characterized in that: The outlet end of the vaporization channel (202) is connected to a second pipe (7), which leads to downstream equipment. A flow meter (8), a pressure transmitter (9), a temperature transmitter a (10), and a ball valve a (11) are connected to the second pipe (7).

4. The liquid carbon dioxide cold energy recovery system as described in claim 3, characterized in that: The second pipe (7) is connected to a third pipe (12), which extends to a safe and open area to release gaseous carbon dioxide at high altitude. A safety release valve (13) is connected to the third pipe (12).

5. The liquid carbon dioxide cold energy recovery system as described in claim 1, characterized in that: The refrigerant inlet (203) is located at the bottom of the storage cavity, and the refrigerant outlet (204) is located above the storage cavity. The refrigerant inlet (203) is connected to the refrigerant container (5) through the fourth pipe, and the cryogenic pump (4) is connected to the fourth pipe.

6. The liquid carbon dioxide cold energy recovery system as described in claim 1, characterized in that: The heat exchanger (3) is a plate heat exchanger (3). The refrigerant outlet (204) is connected to the first channel (301) of the heat exchanger (3) through the fifth pipe (14), and the outlet of the first channel (301) is connected to the refrigerant container (5) through the sixth pipe (15). The fifth pipe (14) is connected to the temperature transmitter b (16) and the gate valve a (17), and the sixth pipe (15) is connected to the gate valve b (18) and the temperature transmitter c (19).

7. A liquid carbon dioxide cold energy recovery system as described in claim 6, characterized in that: A seventh pipe (20) is connected between the fifth pipe (14) and the sixth pipe (15), and a ball valve b (21) is connected to the seventh pipe (20).

8. A liquid carbon dioxide cold energy recovery system as described in claim 6, characterized in that: The inlet end of the second channel (302) of the heat exchanger (3) is connected to an eighth pipe (22), and the outlet end is connected to a ninth pipe (23). The refrigerant enters the heat exchanger (3) through the eighth pipe (22) and is discharged from the ninth pipe (23) to be transported to the equipment that needs to be cooled.

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