A co2 hydrate cycle cold storage device and method

Abstract

The application discloses a CO2 hydrate circulating cold storage device and method. The device comprises a water-oil-emulsifier solution mixing tank, a CO2 hydrate cold storage device, a cold release device and a cold energy utilization area connected in sequence, a CO2 storage tank, a refrigeration device and a control system. The refrigeration device is connected with the mixing tank and the cold storage device respectively. A CO2 discharge port, a mixed liquid injection port, a spray nozzle, a filler layer, a CO2 injection port, a push plate and a filter plate are arranged in the cold storage device from top to bottom. One end of the push plate is connected with the side wall through an extension shaft, and the other end is opposite to the CO2 hydrate crystal discharge port. The control system controls the push plate in the cold storage cavity to work regularly, and the CO2 injection port and the CO2 discharge port are connected with the CO2 storage tank. The control system of the application controls the push plate to work regularly to regularly transfer the CO2 hydrate crystal, shortens the CO2 hydrate generation induction period, accelerates the CO2 hydrate generation, and realizes the continuous operation between the cold storage device and the cold release device.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of industrial refrigeration, and particularly relates to a CO2 hydrate circulating cold storage device and method. BACKGROUND

[0002] With the rapid development of China's economy and the continuous improvement of people's living standards, the demand for electricity of users is also higher and higher. But the reality is that the load and "peak-valley" difference of the power grid are getting larger and larger, which seriously affects the safe operation of the power grid and the safety of power supply. In summer, the proportion of air conditioning load in the total social power load is getting higher and higher, and the use of air conditioning has high concentration, so that it has the characteristics of high power consumption during the peak period of electricity consumption, which is one of the main reasons causing the peak-valley difference of the power grid. Cold storage is a method of storing cold energy in a certain cold storage medium and releasing it when needed, which can alleviate the tension of peak electricity consumption and effectively utilize off-peak power. The traditional cold storage working medium mainly includes water, ice, eutectic salt and gas hydrate. As a new generation of cold storage medium, gas hydrate overcomes the weaknesses of ice cold storage, such as low efficiency, small water storage density, low heat exchange efficiency of eutectic salt, and easy aging failure, and is considered to be the best cold storage medium in terms of comprehensive performance, and has broad development prospects. It is a new generation of cold storage technology. However, there are still a series of problems in the current hydrate cold storage technology, which needs further research and development to promote the application of hydrate cold storage technology in air conditioning systems.

[0003] The existing hydrate cold storage device has the following disadvantages: the conversion rate of hydrate is not high; the hydrate needs to be collected at regular intervals, that is, the equipment is manually closed at certain time intervals to collect the hydrate, which cannot meet the requirements of circulating cold storage. SUMMARY

[0004] To solve the technical problems of low conversion rate of hydrate, the need to manually collect hydrate by closing the equipment at regular intervals, and the inability to meet the requirements of circulating cold storage, the present application provides a CO2 hydrate circulating cold storage device. The present application also provides a CO2 hydrate circulating cold storage method.

[0005] The technical scheme of the present application:

[0006] A CO2 hydrate circulating cold storage device, comprising a water-oil-emulsifier solution mixing tank, a CO2 hydrate cold storage device, a cold release device, a cold energy utilization area, a refrigeration device, a CO2 storage tank and a control system;

[0007] The water-oil-emulsifier solution mixing tank is a high-pressure cavity with a working pressure of 10 MPa or below, has a water injection inlet, an oil-emulsifier mixed solution injection inlet and a water-oil-emulsifier mixed solution discharge outlet, and an evaporator coil I is arranged in the mixing tank cavity. The mixing tank cavity has a stirring device at the bottom;

[0008] The CO2 hydrate cold storage device is a high-pressure cavity with a working pressure of 0-10 MPa, and the cold storage device cavity is provided with a vacuum pumping device; the top of the cold storage device cavity is provided with a mixed liquid injection port, the mixed liquid injection port is communicated with the mixed solution discharge port of the water-oil-emulsifier solution mixing tank and is provided with a high-pressure delivery pump on the pipeline; a spray nozzle is arranged below the mixed liquid injection port; a filler layer is arranged in the middle of the cold storage device cavity, and an evaporator coil II is embedded in the filler layer; a filter plate is arranged at the bottom of the cold storage device cavity, and a push plate is arranged above the filter plate, one end of the push plate is connected with the side wall of the cold storage device cavity through an extension shaft, and the other end of the push plate is opposite to a CO2 hydrate crystal discharge port arranged at the lower part of the cold storage device cavity, and the CO2 hydrate crystal discharge port is communicated with the cold release device through a transmission pipeline; the bottom of the cold storage device cavity is provided with a slurry discharge port; the lower part of the cold storage device cavity is provided with a CO2 injection port, the CO2 injection port is communicated with the gas inlet valve of the CO2 storage tank, and the CO2 injection port is communicated with a CO2 injection hole pipe arranged in the cold storage device cavity, and gas outlets are arranged on the hole pipe; the top of the cold storage device cavity is provided with a CO2 discharge port, and the CO2 discharge port is connected with the inlet of the CO2 storage tank.

[0009] The control system controls the time of the push plate automatic operation;

[0010] The cooling liquid pipe of the refrigeration device is connected with the water-oil-emulsifier solution mixing tank and the CO2 hydrate cold storage device respectively;

[0011] The CO2 gas storage tank is sequentially connected with a condenser I, a thermal expansion valve, the evaporator coil I, a condenser II and the evaporator coil II through a stop valve, the outlet of the evaporator coil II is communicated with the inlet of the CO2 storage tank, and a CO2 refrigeration cycle pipeline is formed;

[0012] The cold release device is a normal-pressure cavity, the cold release device is connected with the CO2 hydrate cold storage device through the transmission pipeline, and the cold release device is connected with the cold energy utilization area through a refrigerant coil; a pressure control valve is arranged at the top of the cold release device cavity, and the pressure control valve is connected with the inlet of the CO2 storage tank.

[0013] The CO2 storage tank is provided with a pressure sensor and a pressure controller for automatically opening and closing the gas inlet valve and the stop valve, and the CO2 hydrate cold storage device is provided with a temperature sensor, and the pressure sensor, the pressure controller and the temperature sensor are connected with the control system.

[0014] A drying filter is arranged on the pipeline between the end of the evaporator coil II and the CO2 storage tank.

[0015] The water-oil-emulsifier solution mixing tank has a circulating slurry injection port, and the slurry discharge port at the bottom of the cold storage device cavity is communicated with the circulating slurry injection port through a pipeline provided with a high-pressure delivery pump; the cold release device has a storage plate for storing CO2 hydrate crystals, and the bottom of the cold release device has a mixed liquid discharge port communicated with the circulating slurry injection port through a pipeline provided with a high-pressure delivery pump.

[0016] The water injection port is connected with a water container through a pipeline provided with a high-pressure delivery pump, and the oil-emulsifier mixed solution injection port is connected with an oil-emulsifier solution container through a pipeline provided with a high-pressure delivery pump.

[0017] A compressor is arranged between the CO2 injection port and the CO2 storage tank.

[0018] The filter plate is made of stainless steel and mechanically installed in the cold storage device cavity, and has a filter hole with a filtering precision of 35-45 μm.

[0019] A heating device is arranged at the bottom of the cold release device.

[0020] A CO2 hydrate circulating cold storage method using the CO2 hydrate circulating cold storage device, comprising the following steps:

[0021] Step one, open the vacuumizing device, vacuumize the CO2 hydrate cold storage device, and then close the vacuumizing device;

[0022] Step two, pump water and oil-emulsifier mixed solution into the water-oil-emulsifier solution mixing tank according to the set proportion, when the volume reaches 1 / 2-3 / 4 of the volume of the container, open the cavity stirring device to make the system uniformly dispersed to form water / oil-emulsifier emulsion, and open the refrigeration device to cool the water / oil-emulsifier emulsion through the cooling liquid in the cooling liquid pipe;

[0023] Step three, inject gas at a set pressure into the CO2 injection hole pipe in the CO2 hydrate cold storage device through the CO2 injection port, and simultaneously pump the water / oil-emulsifier emulsion in the water-oil-emulsifier solution mixing tank into the CO2 hydrate cold storage device through a high-pressure delivery pump, the injection pipeline injects the water / oil-emulsifier emulsion into the cold storage device cavity through a spray nozzle, the refrigeration device is opened, the water / oil-emulsifier emulsion is cooled through the cooling liquid in the cooling liquid pipe, and the water / oil-emulsifier emulsion generates CO2 hydrate slurry rapidly in the packing layer after contacting with the CO2 gas in the cold storage device cavity, and the CO2 storage tank timely supplements high-pressure CO2 gas to the cold storage device cavity through the gas injection pipeline to keep the pressure of the cold storage device cavity stable;

[0024] Step four, when the volume of fluid in the cold storage device cavity occupies 1 / 2-3 / 4, open the hydrate slurry outlet at the bottom of the cold storage device cavity to discharge the hydrate slurry, the CO2 hydrate crystals on the filter plate are separated from the oil phase and gas phase and collected, the push plate is continuously and periodically operated by the control system to automatically transport the CO2 hydrate crystals into the transmission pipeline, and the CO2 gas phase discharged from the top of the cold storage device cavity returns to the CO2 storage tank;

[0025] Step five, the CO2 hydrate crystals enter the cold release device, the CO2 hydrate crystals evaporate to generate CO2 gas under normal pressure and at least normal temperature, and heat exchange is performed with the cold medium utilization area, when the gas pressure in the cavity of the cold release device is greater than the set value of the pressure control valve at the top, the CO2 gas overflows the cold release device and returns to the CO2 storage tank for cyclic utilization.

[0026] Step six, the stop valve of the CO2 storage tank is opened, the collected CO2 gas enters the condenser I along the pipeline and is cooled and liquefied, after being liquefied, the CO2 gas enters the evaporator coil I in the water-oil-emulsifier solution mixing tank through the pressure flow regulating thermal expansion valve, is evaporated again in the evaporator coil I by heat absorption, the temperature in the water-oil-emulsifier solution mixing tank is reduced, the evaporated CO2 gas enters the condenser II and is liquefied again, and then enters the evaporator coil II in the CO2 hydrate cold storage device, the liquefied CO2 is evaporated again in the evaporator coil by heat absorption, the temperature in the CO2 hydrate cold storage device is reduced, and then the CO2 returns to the CO2 storage tank.

[0027] The gas in the CO2 storage tank is automatically controlled by the control system to be used as raw material for preparing CO2 hydrate and as refrigeration medium for circulating refrigeration in the evaporator coil I and the evaporator coil II, including the following steps:

[0028] When the pressure of the pressure sensor of the CO2 storage tank reaches the set pressure value, the inlet valve of the CO2 gas storage tank is automatically opened, the CO2 gas is injected into the CO2 hydrate cold storage device through the gas injection pipeline, and is used to continue to generate CO2 hydrate slurry.

[0029] When the temperature sensor shows that the temperature of the CO2 hydrate cold storage device is higher than the set temperature, the stop valve of the CO2 storage tank is automatically opened, the CO2 gas enters the condenser I, the thermal expansion valve, the evaporator coil I, the condenser II and the evaporator coil II in sequence, provides cold energy for the water-oil-emulsifier solution mixing tank and the CO2 hydrate cold storage device, and finally the CO2 gas returns to the CO2 storage tank.

[0030] Beneficial technical effects of the application

[0031] The application sets the push plate operation time according to the period of CO2 hydrate crystal generation in the cold storage device by the control system, controls the push plate to work periodically to transfer CO2 hydrate crystal periodically, realizes the continuous operation between the cold storage device and the cold release device, automatic operation, and improves the fluidity of hydrate slurry. Moreover, the water-oil-emulsifier solution mixing tank and the CO2 hydrate cold storage device of the application are high-pressure cavities, the two high-pressure cavities are cooled by the refrigeration device, or the refrigeration device and the CO2 refrigeration pipeline are combined to cool, and the stirring device is arranged in the water-oil-emulsifier solution mixing tank, which further shortens the induction period of CO2 hydrate generation to accelerate the generation of CO2 hydrate, and solves the technical problem of long hydrate generation time in the prior art.

[0032] Moreover, the CO2 gas storage tank of the application is connected with the CO2 hydrate production pipeline through the gas inlet valve and connected with the refrigeration pipeline through the stop valve. Therefore, the gas in the CO2 gas storage tank provides raw materials for synthesizing CO2 hydrate crystal and provides cold energy for the synthesis of hydrate in the water-oil-emulsifier solution mixing tank and the cold storage device. If the temperature of the external environment is very high sometimes, the cooling liquid refrigeration alone may not reach the thermodynamic conditions of hydrate generation, so liquid carbon dioxide refrigeration is further introduced to cool together, which makes the cooling effect better, and the carbon dioxide resource can be efficiently utilized. In summary, the application provides a reasonable and effective way for CO2 recycling, which has important significance for practical application.

[0033] Preferably, the gas inlet valve and the stop valve are provided with a pressure controller for automatically opening and closing, and a pressure sensor is arranged in the CO2 storage tank to monitor the change of the gas pressure in the storage tank. A certain pressure value is set in the control system, when the value is reached, it indicates that the pressure in the CO2 storage tank reaches the limit value, the gas inlet valve is automatically opened, the CO2 gas enters the cold storage device to continue to generate emulsion, and then returns to the storage tank to realize the recycling. At the same time, the temperature sensor arranged in the CO2 hydrate cold storage device realizes temperature monitoring, when the temperature is higher than a certain design temperature set in the control system, it indicates that the cooling effect is not enough, the stop valve on the CO2 storage tank is automatically opened, the CO2 is condensed into liquid through the condenser, and then enters the evaporator coil I and the evaporator coil II to realize the evaporation of CO2 to provide cold energy for the solution mixing tank and the cold storage device, and then returns to the storage tank. Therefore, the automatic operation of CO2 for synthesizing hydrate and refrigeration is realized.

[0034] Preferably, the CO2 gas evaporated in the evaporator coil II passes through the drying filter to remove the water vapor mixed in the CO2 hydrate cold storage device, so that the gas is as dry as possible before returning to the CO2 storage tank, which can prevent corrosion of the pipeline and equipment.

[0035] Preferably, the cold releasing device and the CO2 hydrate cold storage device are both provided with valves controlled by the control system, and a liquid level sensor is arranged in each of the cold storage device and the cold releasing device. In the CO2 hydrate cold storage device, the push plate is controlled to operate periodically by the control system, and the valve at the bottom of the CO2 hydrate cold storage device is opened to allow the unreacted emulsion below to be recycled and transported to the water-oil-emulsifier solution mixing tank through a pipeline. Similarly, in the cold releasing device, when the CO2 hydrate crystals are decomposed by heat and the liquid level reaches a set value, the control system controls the valve at the bottom of the cold releasing device to be opened, and the liquid phase is transported to the water-oil-emulsifier solution mixing tank through a pipeline below for recycling. This process not only realizes the circulation of the process flow, but also saves raw materials. In addition, the cold releasing device is provided with a storage plate for storing CO2 hydrate crystals, and the storage plate is provided with holes. When the valve below the cold releasing device is opened, the CO2 hydrate crystals are separated from the liquid phase.

[0036] In summary, the present application realizes the continuous and rapid synthesis of CO2 hydrate and the circulation and automatic operation of the entire process flow.

[0037] Preferably, the water-oil-emulsifier solution mixing tank is a high-pressure container, and is connected to a water container and an oil-emulsifier solution container through high-pressure delivery pumps, respectively.

[0038] Preferably, a compressor is arranged between the CO2 injection inlet and the CO2 storage tank, and the CO2 gas is further pressurized before entering the CO2 hydrate cold storage device to meet the high pressure required in the cavity of the cold storage device.

[0039] Preferably, the filter plate is made of stainless steel and is mechanically installed in the cavity of the cold storage device, and has a filter aperture with a filtering precision of 35-45 μm to ensure that the hydrate oil slurry can pass through while the CO2 hydrate crystals are retained on the filter plate.

[0040] Preferably, a heating device is arranged at the bottom of the cold releasing device to accelerate the heat dissipation of the CO2 hydrate crystals. BRIEF DESCRIPTION OF DRAWINGS

[0041] Figure 1 is a structural schematic diagram of an embodiment of a CO2 hydrate circulating cold storage device of the present application.

[0042] Reference numerals in the attached diagram: 1-CO2 hydrate cold storage device, 2-cold release device, 3-cold energy utilization area, 4-mixed liquid injection port, 5-spray nozzle, 6-packing layer, 7-packing tray, 8-mixed liquid discharge port, 9-filter plate, 10-telescopic shaft, 11-push plate, 12-CO2 gas injection port, 13-perforated pipe, 14-transmission pipe, 15-heating device, 16-storage plate, 17-pressure control valve, 18-refrigerant coil, 19-CO2 storage tank, 20-water-oil-emulsifier solution mixing tank, 21-water container, 22-oil-emulsifier solution container, 23-stirring device, 24-vacuum device, 25-condenser I, 26-thermal expansion valve, 27-evaporator coil I, 28-evaporator coil II, 29-condenser II, 30-drying filter, 31-compressor. Detailed Implementation

[0043] The following is based on the appendix Figure 1 The technical solution of the present invention will be further illustrated with specific examples to enable those skilled in the art to have a deeper and more comprehensive understanding of the present invention.

[0044] Example 1

[0045] like Figure 1 As shown, a CO2 hydrate circulating cold storage device in this embodiment includes a water-oil-emulsifier solution mixing tank 20, a CO2 hydrate cold storage device 1, a cold release device 2, a cold energy utilization area 3, a refrigeration device, a CO2 storage tank 19, and a control system.

[0046] The water-oil-emulsifier solution mixing tank 20 is a high-pressure chamber with a working pressure of 0-10 MPa (i.e., 10 MPa and below) and a working temperature of -30 to 10°C. The right side wall of the chamber has a water inlet and an oil-emulsifier solution inlet, which are connected to the water container 21 and the oil-emulsifier solution container 22, respectively. The bottom of the water-oil-emulsifier solution mixing tank 20 has a mixed solution outlet 8, which is connected to the mixed solution inlet 4 of the CO2 hydrate cold storage device 1. The top and bottom of the water-oil-emulsifier solution mixing tank 20 are respectively equipped with circulating slurry inlets, which are connected to the slurry outlet of the CO2 hydrate cold storage device 1 and the liquid phase outlet of the cold release device 2. High-pressure delivery pumps are installed between the water-oil-emulsifier solution mixing tank 20 and the water container 21, the oil-emulsifier solution container 22, the mixture outlet 8 of the water-oil-emulsifier solution mixing tank 20 and the mixture inlet 4 of the CO2 hydrate cold storage device 1, the bottom slurry outlet of the CO2 hydrate cold storage device 1 and the water-oil-emulsifier solution mixing tank 20, and the liquid phase outlet of the cold release device 2 and the water-oil-emulsifier solution mixing tank 20. A stirring device 23 is located at the bottom of the water-oil-emulsifier solution mixing tank 20.

[0047] The oil in the oil-emulsifier solution container 22 is selected from diesel oil or other oil products with condensation point below -20℃ or liquid hydrocarbons; the emulsifier is selected from Tween-80 with dosage of 1%-2%.

[0048] The CO2 hydrate cold storage device 1 is a high-pressure cavity with working pressure of 0-10 MPa and working temperature of -30-10℃, and is connected with a vacuum pumping device 24. The top of the cavity is provided with a mixed liquid injection port 4, which is communicated with the water-oil-emulsifier solution mixing tank 20, and a spray nozzle 5 is arranged below the mixed liquid injection port 4. The lower part of the cavity is provided with a CO2 injection port 12, which is communicated with the gas inlet valve of the CO2 storage tank 19 and a CO2 injection hole pipe 13 in the cavity. The hole pipe 13 is arranged in a horizontal spiral shape in the cavity, and a plurality of gas outlet holes are arranged on the spiral pipe. In the cooling environment, CO2 gas and water / oil-emulsifier emulsion contact and hydrate reaction occurs in the filler layer 6 to generate CO2 hydrate slurry. The middle part of the cavity is provided with a filler layer 6, which is located on a filler tray 7, and an evaporator coil II 28 is embedded in the filler layer 6. The internal refrigerant is used to reduce the temperature of the fluid and promote the generation of gas hydrate. The bottom of the cavity is provided with a CO2 hydrate crystal discharge port, which is communicated with the cold release device 2 through a transmission pipeline 14. A filter plate 9 is arranged at the bottom of the cavity, and a push plate 11 with an extension shaft 10 is arranged above the filter plate 9. One end of the push plate 11 is connected with the side wall of the cavity through the extension shaft 10, and the other end of the push plate 11 is opposite to the CO2 hydrate crystal discharge port. The push plate is controlled by a control system to work for a certain time. The control push plate 11 is automatically operated periodically, and the generated CO2 hydrate crystals on the filter plate 9 are pushed to the transmission pipeline 14 through the CO2 hydrate crystal discharge port by horizontal movement, so that the CO2 hydrate crystals enter the transmission pipeline 14 and then enter the storage plate 16 of the cold release device 2.

[0049] The top of the cavity of the CO2 hydrate cold storage device 1 is provided with a recycling CO2 discharge port, which is communicated with the inlet of the CO2 storage tank 19.

[0050] The lower part of the CO2 hydrate cold storage device 1 is provided with a slurry discharge port and a valve, which are communicated with the water-oil-emulsifier solution mixing tank 20 through a pipeline provided with a high-pressure delivery pump. The CO2 hydrate cold storage device 1 is provided with a liquid level sensor connected with a control system. When the fluid in the cavity occupies 1 / 2-3 / 4 of the volume, the valve of the hydrate oil slurry discharge port at the bottom of the cavity is opened, the mixed slurry is delivered into the water-oil-emulsifier solution mixing tank 20 through the high-pressure delivery pump for repeated use, the CO2 hydrate crystals on the filter plate are separated from the oil phase and gas phase, and are collected.

[0051] The cooling liquid pipe of the refrigeration device is connected with the water-oil-emulsifier solution mixing tank and the CO2 hydrate storage device respectively. That is, the cooling liquid pipe of the refrigeration device transports into the water-oil-emulsifier solution mixing tank for refrigeration, and then returns to the refrigeration device for circulation. The water-oil-emulsifier solution mixing tank 20 is cooled by the refrigeration device or the refrigeration medium in the evaporator coil I 27 in the cavity. The cooling liquid pipe of the refrigeration device transports into the CO2 hydrate storage device for refrigeration, and then returns to the refrigeration device for circulation. The CO2 hydrate storage device 1 is cooled by the refrigeration device or the refrigeration medium in the evaporator coil II 28 in the cavity.

[0052] The condenser I 25 and the condenser II 29 are finned condensers. The evaporator coil I 27 and the evaporator coil II 28 are cooled by liquid CO2. The stop valve above the CO2 storage tank is connected with the condenser I 25, the thermal expansion valve 26 and the evaporator coil I 27 in sequence. When the stop valve above the CO2 storage tank 19 is opened, CO2 gas is liquefied by the condenser I 25. The liquefied CO2 is adjusted in pressure and flow by the thermal expansion valve 26, and then enters the evaporator coil I 27 in the water-oil-emulsifier solution mixing tank 20. The CO2 absorbs heat in the evaporator coil I 27 to evaporate again, so that the temperature in the water-oil-emulsifier solution mixing tank 20 is reduced, which is conducive to the formation of emulsion. The end of the evaporator coil I 27 is connected with the condenser II 29, and the evaporated CO2 gas is liquefied again. The condenser II 29 is connected with the evaporator coil II 28, and the liquefied CO2 absorbs heat in the evaporator coil II 28 to evaporate again, so that the temperature in the CO2 hydrate storage device 1 is reduced, which creates low-temperature conditions for the formation of CO2 hydrate crystals. The end of the evaporator coil II 28 is connected with the drying filter 30, and the drying filter 30 is connected with the gas inlet of the CO2 storage tank 19. The CO2 gas is dried and then returns to the gas storage tank 19, realizing the recycling of CO2 gas.

[0053] The filter plate 9 is made of stainless steel and mechanically installed in the cavity. The filter plate 9 has a filter hole with a filtering accuracy of 35-45 μm, for example, 40 μm.

[0054] The outer wall of the transmission channel 14 is made of polyurethane foam plastic for heat preservation, so as to reduce the decomposition of CO2 hydrate crystals during transportation. As the transmission proceeds, the diameter of the pipeline gradually increases, which is convenient for the transportation of crystals.

[0055] The compressor 31 is arranged between the hole pipe 13 and the CO2 storage tank 19.

[0056] The filler layer 6 in the CO2 hydrate storage device 1 is made of existing industrial filler, preferably copper filler. The filler layer 6 in the storage device 1 can be replaced by a tower plate.

[0057] The cold releasing device 2 is a normal pressure cavity, which is connected with the CO2 hydrate cold storage device 1 through a transmission pipeline 14. A storage plate 16 is arranged in the cold releasing cavity, and the CO2 hydrate crystals are gathered on the storage plate 16 in the cold releasing device 2. The storage plate is provided with a hole, and the liquid phase formed by the decomposition of the CO2 hydrate crystals enters the bottom of the cold releasing device through the hole. A heating device 15 is arranged at the bottom of the cold releasing cavity to promote the decomposition of the hydrate crystals, and the gas escaping from the top of the cavity is connected with the cold energy utilization area 3 through a refrigerant coil 18. The heating device 15 is an electric heating wire or a heat exchange coil through which hot steam is introduced. A pressure control valve 17 is arranged at the top of the cavity of the cold releasing device 2, and the pressure control valve 17 is connected with a CO2 storage tank 19. The decomposition of the crystals causes the pressure in the cavity to rise, and when the gas pressure is greater than the set value of the pressure control valve 17, the control valve 17 is opened, and the CO2 gas enters the CO2 storage tank 19.

[0058] The bottom of the cavity of the cold releasing device 2 is provided with a liquid phase discharge outlet, which is transported to a water-oil-emulsifier solution mixing tank 20 through a pipeline provided with a high-pressure delivery pump for recycling. The valve at the bottom of the cold releasing device 2 is controlled to be opened and closed by the control system. A liquid level sensor connected with the control system is arranged in the cold releasing device 2. When the CO2 hydrate crystals are decomposed by heat in the cold releasing device 2 and the liquid level reaches a set value, the control system controls to open the valve below the cold releasing device 2, and the liquid is transported to the water-oil-emulsifier solution mixing tank 20 through the pipeline below for recycling. This process not only realizes the automatic circulation of the process flow, but also saves raw materials.

[0059] The CO2 storage tank 19 is provided with a pressure sensor, and the gas inlet valve and the stop valve of the CO2 storage tank 19 are provided with a pressure controller for automatically opening and closing them. The CO2 hydrate cold storage device 1 is provided with a temperature sensor, and the pressure sensor, the pressure controller and the temperature sensor connector are connected with the control system respectively. The gas in the CO2 storage tank 19 is automatically controlled by the control system to be used as raw materials for preparing CO2 hydrate and as a refrigeration medium for circulating refrigeration in the evaporator coil I 27 and the evaporator coil II 28. When the pressure sensor in the CO2 storage tank 19 reaches the pressure value set by the control system, it indicates that the pressure in the CO2 storage tank 19 reaches the limit value, and the gas inlet valve is automatically opened, and the CO2 gas enters the cold storage device 1 to continue to generate emulsion, realizing recycling. When the temperature sensor arranged in the CO2 hydrate cold storage device 1 is higher than a certain temperature set by the control system, it indicates that the cooling effect is not enough, and the stop valve on the CO2 storage tank 19 is automatically opened, and the CO2 is condensed into liquid through the condenser, and then enters the evaporator coil I 27 and the evaporator coil II 28 to realize the evaporation refrigeration of CO2, providing cold energy for the solution mixing tank and the cold storage device, and realizing automatic operation.

[0060] Example 2

[0061] A CO2 hydrate cycle refrigeration method using the device of Example 1, the whole device is automatically operated, the steps are as follows:

[0062] Step one, open the vacuum pump 24, after the CO2 hydrate storage device 1 is vacuumized, close the vacuum pump 24;

[0063] If the CO2 hydrate storage device 1 needs to be cleaned, it is first cleaned and then vacuumized. First, open the top cover of the CO2 hydrate storage device 1, and flush the inside of the cavity with distilled water. After drying, use the vacuum pump 24 to pump air out of the cavity until it is in a vacuum state to remove air in the cavity. After the cavity reaches the required vacuum degree, close the vacuum pump 24;

[0064] Step two, open the flow valves of the water container 21 and the oil-emulsifier solution container 22, and pump water and oil-emulsifier mixed solution into the water-oil-emulsifier solution mixing tank 20 at a set ratio through the high-pressure delivery pump. When the volume of the mixed solution reaches 3 / 4 of the volume of the container, open the stirring device 23 in the cavity, control the rotating speed at 300 rpm-500 rpm, for example, 500 r / min, and start the stirring blade to make the system uniformly dispersed to form a water / oil-emulsifier emulsion. Open the refrigeration device, and the cooling liquid (aqueous ethylene glycol solution) in the cooling liquid pipe cools and cools the water / oil-emulsifier emulsion;

[0065] Step three, inject a certain pressure of CO2 gas through the CO2 injection port at the bottom of the cavity of the CO2 hydrate storage device 1, and pump the water / oil-emulsifier emulsion in the water-oil-emulsifier solution container 22 to the CO2 hydrate storage device 1 through the high-pressure delivery pump. The injection pipeline uniformly sprays the emulsion in the tower through the spray nozzle 5. Open the refrigeration device, and the cooling liquid (aqueous ethylene glycol solution) in the cooling liquid pipe cools and cools the fluid. The water / oil-emulsifier emulsion in the CO2 hydrate storage device 1 contacts with CO2 and quickly generates CO2 hydrate slurry in the filler layer 6. When the pressure of the pressure sensor of the CO2 storage tank 19 reaches the pressure value set by the control system, the gas inlet valve of the CO2 storage tank 19 is automatically opened, and CO2 gas is timely supplemented to the cavity of the storage device through the gas injection pipeline to keep the pressure stable;

[0066] The CO2 hydrate slurry includes a liquid phase and CO2 hydrate crystals, and the CO2 hydrate crystals exist in the slurry and can be separated from the liquid phase through the filter plate 9;

[0067] The minimum pressure requirement for the formation of CO2 hydrate is 0.4 MPa, and the temperature is controlled at about 0°C. The pressure is ensured by the CO2 high-pressure gas entering the CO2 hydrate storage device 1. The temperature in the CO2 hydrate storage device 1 is directly controlled by the refrigeration device, or indirectly controlled by the water / oil-emulsifier emulsion delivered by the water-oil-emulsifier solution mixing tank 20 through heat exchange with the surrounding solution via the evaporator coil II 28 placed in the storage device cavity.

[0068] To improve the formation rate of CO2 hydrate, the pressure and temperature can be reduced, for example, 0.4 MPa to 10 MPa, or 0.4 MPa to 6.0 MPa; -1 to -30°C, or -1 to -10°C.

[0069] Step four, when the fluid in the CO2 hydrate storage device 1 occupies about 1 / 2 to 3 / 4 of the volume, the hydrate oil slurry discharge port at the bottom is opened. The hydrate oil slurry passes through the high-pressure delivery pump into the water-oil-emulsifier solution mixing tank 20. The filter plate 9 placed at the bottom of the storage device collects more CO2 hydrate crystals and separates the oil phase and gas phase, and is collected. The control system controls the push plate 11 to work continuously and periodically, delivering CO2 hydrate crystals to the transmission pipeline 14. Unreacted CO2 gas is discharged from the top of the storage device cavity into the CO2 storage tank 19 for recycling.

[0070] Step five, CO2 hydrate crystals are collected on the storage plate 16 in the cold release device 2. The heating device 15 in the cold release device 2 is opened to heat the hydrate crystals. The crystals evaporate to produce CO2 gas, which is exchanged with the refrigerant coil 18 and the refrigerant utilization area 3. The liquid phase is delivered to the water-oil-emulsifier solution mixing tank by the lower pipeline. When the gas pressure in the cold release cavity is greater than the set value of the pressure control valve 17 at the top, the CO2 gas enters the CO2 storage tank 19 for recycling. When the liquid level reaches the set value due to the decomposition of CO2 hydrate crystals, the control system will control the opening of the valve below the cold release device 2. The liquid phase is delivered to the water-oil-emulsifier solution mixing tank 20 by the lower pipeline for recycling.

[0071] Step six, when the temperature of the CO2 hydrate storage device 1 rises to a certain set value, for example, 0℃, or -3℃, or even lower temperature, the valve of the CO2 storage tank 19 is automatically opened, and the CO2 gas enters the condenser I 25 for cooling and liquefaction. The liquefied CO2 passes through the thermal expansion valve 26 to adjust the pressure and flow rate, and then enters the evaporator coil I 27 in the water-oil-emulsifier solution mixing tank 20. The liquefied CO2 absorbs heat in the evaporator coil I 27 and evaporates again, reducing the temperature in the water-oil-emulsifier solution mixing tank 20. The evaporated CO2 gas is liquefied again in the condenser II 29 and enters the evaporator coil II 28, evaporates again, and reduces the temperature in the CO2 hydrate storage device 1. The CO2 gas passes through the drying filter 30 and enters the CO2 storage tank 19, realizing the cycle.

[0072] Step seven, the temperature and stirring speed are controlled unchanged, and the CO2 hydrate induction time is verified by increasing the pressure in the CO2 hydrate storage device 1. The results are shown in Table 1.

[0073] Table 1. Experimental data

[0074]

[0075] From Table 1, it can be seen that by using the device of Example 1 and the control conditions of Example 2, the CO2 hydrate induction time is significantly shortened under the conditions of increasing pressure, stirring rate and reducing temperature.

[0076] The above describes representative examples and test examples of the present application, but the present application is not limited to the specific details of the above-described embodiments. Within the technical concept of the present application, various simple modifications can be made to the technical solutions of the present application, and changes and combinations obvious to those skilled in the art are all within the protection scope of the present application.

Claims

1. A CO2 hydrate circulating cold storage device, characterized in that... Includes a water-oil-emulsifier solution mixing tank, a CO2 hydrate cold storage device, a cold release device, a cold energy utilization area, a refrigeration unit, a CO2 storage tank, and a control system; The water-oil-emulsifier solution mixing tank is a high-pressure chamber with a working pressure of 10MPa or less. It has a water inlet, an oil-emulsifier solution inlet, and a water-oil-emulsifier solution outlet. An evaporator coil I is installed inside the mixing tank chamber, and a stirring device is provided at the bottom of the mixing tank chamber. The CO2 hydrate cold storage device is a high-pressure chamber with a working pressure of 0-10 MPa, and the chamber is equipped with a vacuum device. The top of the chamber has a mixed liquid injection port, which is connected to the mixed solution outlet of the water-oil-emulsifier solution mixing tank, and a high-pressure delivery pump is installed on the pipeline. Spray nozzles are arranged below the mixed liquid injection port. A packing layer is arranged in the middle of the chamber, and an evaporator coil II is embedded within the packing layer. A filter plate is located at the bottom of the chamber, and a push plate is arranged above the filter plate. One end of the push plate is connected to the side wall of the chamber via a telescopic shaft. The push plate is connected to the CO2 hydrate crystal outlet located at the bottom of the cold storage device cavity. The CO2 hydrate crystal outlet is connected to the cold release device via a transmission pipe. The bottom of the cold storage device cavity has a slurry outlet. The lower part of the cold storage device cavity has a CO2 injection port. The air inlet valve of the CO2 storage tank is connected to the CO2 injection port. The CO2 injection port is connected to a CO2 injection hole pipe located in the cold storage device cavity. The hole pipe has air outlets. The top of the cold storage device cavity has a CO2 outlet, which is connected to the inlet of the CO2 storage tank. The control system controls the periodic automatic operation time of the push plate; The cooling liquid pipe of the refrigeration device is connected to the water-oil-emulsifier solution mixing tank and the CO2 hydrate cold storage device, respectively. The CO2 storage tank is connected in sequence to condenser I, thermal expansion valve, evaporator coil I, condenser II and evaporator coil II via a shut-off valve. The outlet of evaporator coil II is connected to the inlet of the CO2 storage tank, forming a CO2 refrigeration circulation pipeline. The cooling device is an atmospheric pressure chamber. The cooling device is connected to the CO2 hydrate cold storage device through the transmission pipeline. The cooling device is connected to the cold energy utilization area through the refrigerant coil. A pressure control valve is installed at the top of the cooling device chamber. The pressure control valve is connected to the inlet of the CO2 storage tank.

2. The apparatus according to claim 1, characterized in that... The CO2 storage tank is equipped with a pressure sensor and a pressure controller that controls the automatic opening and closing of the inlet valve and the shut-off valve. The CO2 hydrate cold storage device is equipped with a temperature sensor. The pressure sensor, pressure controller and temperature sensor are connected to the control system.

3. The apparatus according to claim 1, characterized in that... A drying filter is provided on the pipeline between the end of the evaporator coil II and the CO2 storage tank.

4. The apparatus according to claim 1, characterized in that... The water-oil-emulsifier solution mixing tank has a circulating slurry injection port, and the slurry discharge port at the bottom of the cold storage device cavity is connected to the circulating slurry injection port through a pipeline equipped with a high-pressure delivery pump; the cold release device has a storage plate for storing CO2 hydrate crystals, and the bottom of the cold release device has a mixed liquid discharge port, which is connected to the circulating slurry injection port through a pipeline equipped with a high-pressure delivery pump.

5. The apparatus according to claim 1, characterized in that... The water inlet is connected to a water container via a pipeline equipped with a high-pressure delivery pump, and the oil-emulsifier mixed solution inlet is connected to an oil-emulsifier solution container via a pipeline equipped with a high-pressure delivery pump.

6. The apparatus according to claim 1, characterized in that... A compressor is provided between the CO2 injection port and the CO2 storage tank.

7. The apparatus according to claim 1, characterized in that... The filter plate is made of stainless steel and is mechanically installed in the cavity of the cold storage device. It has filter holes and a filtration accuracy of 35-45μm.

8. The apparatus according to claim 1, characterized in that... A heating device is installed at the bottom of the cooling device.

9. A method for circulating CO2 hydrate for cold storage, characterized in that... The CO2 hydrate circulating cold storage device according to any one of claims 1-8 includes the following steps: Step 1: Turn on the vacuum pump to evacuate the CO2 hydrate cold storage device, then turn off the vacuum pump. Step 2: Pump water and oil-emulsifier mixed solutions into the water-oil-emulsifier solution mixing tank according to the set ratio. When the volume reaches 1 / 2-3 / 4 of the container volume, turn on the in-cavity stirring device to disperse the system evenly and form a water / oil-emulsifier emulsion. Turn on the refrigeration device to cool the water / oil-emulsifier emulsion through the coolant in the cooling pipe. Step 3: Inject gas at a set pressure into the CO2 injection port of the CO2 hydrate cold storage device. Simultaneously, pump the water / oil-emulsifier emulsion from the water-oil-emulsifier solution mixing tank to the CO2 hydrate cold storage device via a high-pressure pump. Inject the water / oil-emulsifier emulsion into the cold storage device cavity through a spray nozzle via an injection pipeline. Turn on the refrigeration device and cool the water / oil-emulsifier emulsion with the coolant in the cooling liquid pipe. After the water / oil-emulsifier emulsion comes into contact with CO2 gas in the cold storage device cavity, it quickly generates CO2 hydrate slurry in the packing layer. The CO2 storage tank promptly replenishes the cold storage device cavity with high-pressure CO2 gas through the gas injection pipeline to maintain stable pressure in the cold storage device cavity. Step 4: When the fluid in the cold storage device cavity occupies 1 / 2-3 / 4 of the volume, open the hydrate oil slurry outlet at the bottom of the cold storage device cavity to discharge the hydrate oil slurry. The CO2 hydrate crystals remaining on the filter plate are separated from the oil phase and gas phase and collected. The push plate is continuously and periodically operated by the control system to automatically transport the CO2 hydrate crystals to the transmission pipeline. The CO2 gas phase discharged from the top of the cold storage device cavity returns to the CO2 storage tank. Step 5: The CO2 hydrate crystals enter the cooling device. The CO2 hydrate crystals evaporate under normal pressure and at least normal temperature to generate CO2 gas, which exchanges heat with the refrigerant utilization area. When the gas pressure in the cooling device chamber is greater than the set value of the pressure control valve at the top, the CO2 gas overflows from the cooling device and returns to the CO2 storage tank for recycling. Step Six: The shut-off valve of the CO2 storage tank is opened, and the collected CO2 gas enters the condenser I along the pipeline and is cooled and liquefied. After liquefaction, the pressure and flow rate are regulated by the thermal expansion valve and then enter the evaporator coil I in the water-oil-emulsifier solution mixing tank. In the evaporator coil I, heat is absorbed and evaporates again, which lowers the temperature inside the water-oil-emulsifier solution mixing tank. The evaporated CO2 gas enters the condenser II and is liquefied again before entering the evaporator coil II in the CO2 hydrate cold storage device. The liquefied CO2 absorbs heat and evaporates again in the evaporator coil, which lowers the temperature inside the CO2 hydrate cold storage device, and then returns to the CO2 storage tank.

10. The method according to claim 9, characterized in that... The control system automatically controls the gas in the CO2 storage tank to be used as raw material for the preparation of CO2 hydrate and as a refrigerant medium for circulating refrigeration in evaporator coil I and evaporator coil II, including the following steps: When the pressure sensor of the CO2 storage tank reaches the set pressure value, the inlet valve of the CO2 gas storage tank automatically opens, and CO2 gas is injected into the CO2 hydrate cold storage device through the injection pipeline to continue generating CO2 hydrate slurry. When the temperature sensor shows that the temperature of the CO2 hydrate cold storage device is higher than the set temperature, the shut-off valve of the CO2 storage tank automatically opens, and CO2 gas enters the condenser I, thermal expansion valve, evaporator coil I, condenser II and evaporator coil II in sequence to provide cooling capacity for the water-oil-emulsifier solution mixing tank and the CO2 hydrate cold storage device. Finally, the CO2 gas returns to the CO2 storage tank.

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