Liquefied natural gas cold energy comprehensive utilization system

Abstract

The utility model belongs to the technical field of cold energy comprehensive utilization systems, and particularly relates to a liquefied natural gas cold energy comprehensive utilization system. Comprising a tank car receiving part, an LNG vertical storage tank, an air temperature type vaporizer, a circulating water type LNG vaporizer, a steam heat exchanger and a high-pressure natural gas conveying pipeline, a circulating water channel of the circulating water type LNG vaporizer is externally connected with an industrial field unit circulating cooling water system, and cooling water flows into the circulating water channel of the circulating water type LNG vaporizer; the air temperature type vaporizer and the circulating water type LNG vaporizer are communicated in parallel, and the two sets of equipment are started at the same time to improve the efficiency in the gas use peak. According to the circulating water type LNG gasifier, cooling water from an industrial field unit exchanges heat with liquefied natural gas, the natural gas is heated and gasified, meanwhile, the cooling water is cooled, the cooled cooling water flows back to the industrial field unit to cool equipment, and comprehensive utilization of LNG cooling capacity is achieved.

Description

Technical Field

[0001] The utility model relates to a liquid natural gas cold capacity comprehensive utilization system, belonging to the technical field of cold capacity comprehensive utilization systems. Background Art

[0002] Natural gas is a naturally occurring fuel, the main component of which is methane. It is a clean and efficient energy source, and produces less harmful substances such as carbon dioxide and sulfide after combustion, causing less pollution to the environment. Natural gas has the characteristics of high calorific value, easy combustion, colorless and odorless, and is widely used in industry, households, commerce and other fields.

[0003] After natural gas is liquefied at ultra-low temperatures, it forms liquefied natural gas (LNG), with a boiling point of about -162°C. Compared with gaseous natural gas, liquefied natural gas has a higher energy density, and the volume of liquefied natural gas is about 1 / 600 of that of gaseous natural gas, which is convenient for long-distance transportation and storage. It is suitable for areas far away from natural gas pipelines and is usually transported by LNG tankers or LNG tankers.

[0004] In industrial production, many industrial production processes need to burn natural gas as energy, such as steel, chemical, glass and other industries. The combustion of natural gas can provide high-temperature heat energy for heating smelting, production and other processes. Liquefied natural gas needs to be gasified by a liquefied natural gas gasification system to form a gaseous natural gas at 200℃~400℃ before it can be burned. The existing liquefied natural gas gasification system cannot utilize the coldness of liquefied natural gas during operation, which wastes a lot of energy and cannot effectively save energy. Utility Model Content

[0005] The purpose of the utility model is to provide a liquid natural gas refrigeration comprehensive utilization system to solve the technical problems existing in the prior art as mentioned above.

[0006] The technical solution provided by the utility model is as follows: a liquefied natural gas cold capacity comprehensive utilization system, comprising a tank truck receiving part, an LNG vertical storage tank, an air-temperature vaporizer, a circulating water LNG vaporizer, a steam heat exchanger, a pressure regulator, an odorizing device and a high-pressure natural gas transmission pipeline, wherein the output end of the tank truck receiving part is respectively connected to the input end of the LNG vertical storage tank, the input end of the air-temperature vaporizer and the liquefied natural gas input end of the circulating water LNG vaporizer through a pipeline, and the output end of the LNG vertical storage tank is respectively connected to the input end of the air-temperature vaporizer and the input end of the circulating water LNG The liquid natural gas input end of the vaporizer is connected through a pipeline, and the output end of the air-temperature vaporizer and the gaseous natural gas output end of the circulating water LNG vaporizer are respectively connected to the natural gas input end of the steam heat exchanger through pipelines; the circulating water channel of the circulating water LNG vaporizer is externally connected to the circulating cooling water system of the industrial on-site unit, and the cooling water used by the industrial on-site unit flows into the circulating water channel of the circulating water LNG vaporizer through the cooling water pipeline. The input end and output end of the circulating water channel of the circulating water LNG vaporizer are respectively provided with an inlet water temperature sensor and an outlet water temperature sensor.

[0007] The air-temperature vaporizer and circulating water LNG vaporizer are connected in parallel, and the two sets of equipment are activated at the same time during peak gas consumption to improve efficiency; the input end of the tank truck receiving part is connected to the LNG vertical storage tank and the vaporizer respectively, which can realize the storage and gasification of LNG at the same time. While transporting liquid natural gas into the storage tank, it can also ensure uninterrupted gas supply to the site.

[0008] The circulating water LNG vaporizer uses the hotter cooling water from the industrial site unit to exchange heat with liquid natural gas, so that the natural gas is heated and gasified, and the cooling water is cooled. The cooled cooling water flows back to the industrial site unit again to cool the equipment. The inlet water temperature sensor and the outlet water temperature sensor are used to monitor the temperature of the cooling water to avoid overcooling and freezing of the cooling water. This method makes full use of the cold capacity of liquid natural gas. Compared with the traditional cooling tower cooling method of the industrial site unit, it saves the energy consumption of pumping cooling water to the top of the tower. At the same time, since the cooling water is cooled in the closed LNG vaporizer, it also avoids the evaporation of water in the traditional cooling tower cooling process, greatly reducing the consumption of cooling water. Moreover, the cooling water is always circulated in a closed space. Compared with the open cooling tower heat dissipation method, it also avoids the entry of various impurities into the cooling water, reducing daily maintenance work.

[0009] On the basis of the above technical solution, the present invention can also be improved as follows.

[0010] Furthermore, the gaseous natural gas output end of the circulating water type LNG vaporizer is connected to a first temperature sensor, and when the temperature of the main pipe at the output end of the circulating water type LNG vaporizer is lower than 8°C, an alarm signal is automatically sent out; when the temperature of the main pipe at the output end of the circulating water type LNG vaporizer is lower than 3°C, there is a risk of freezing of the cooling water pipeline, so in addition to the automatic alarm, an instruction to cut off the emergency shut-off valve at the liquefied natural gas input end of the circulating water type LNG vaporizer will be issued, that is, to stop delivering liquefied natural gas to the circulating water type LNG vaporizer to avoid malfunctions caused by freezing of cooling water.

[0011] Furthermore, the tank truck and the input end of the tank truck receiving part are connected through a pipeline. The tank truck receiving part includes a tank truck gas phase port, a tank truck liquid phase port and a pressure regulating device. The tank truck liquid phase port is connected to the input end of the LNG vertical storage tank, the input end of the air-temperature vaporizer and the liquid natural gas input end of the circulating water LNG vaporizer through a pipeline; the tank truck liquid phase port is also connected to the liquid natural gas inlet and outlet of the pressure regulating device, and the gaseous natural gas outlet of the pressure regulating device is connected to the tank truck gas phase port; the pressure regulating device is a small vaporizer.

[0012] The beneficial effect of adopting the above further scheme is that the liquid phase port of the tank truck receiving part is connected to the liquid natural gas inlet of the pressure regulating device through a pipeline, and the gaseous natural gas outlet of the pressure regulating device is connected to the gas phase port of the tank truck, which is used to input the gasified liquid natural gas into the tank truck, increase the pressure in the tank truck, and rely on the pressure difference to pressurize the LNG into the LNG vertical storage tank; at the same time, the gaseous natural gas outlet of the pressure regulating device is also connected to the gaseous natural gas main, so that the gaseous natural gas can be directly transported to the natural gas transportation main.

[0013] Furthermore, the natural gas output end of the steam heat exchanger and the input end of the pressure regulator are connected through a pipeline.

[0014] Furthermore, the steam channel of the steam heat exchanger is externally connected to a steam circulation system.

[0015] The beneficial effect of adopting the above further scheme is that the steam heat exchanger is used to heat the low-temperature gaseous natural gas to a high-temperature gaseous state, and the heat of the steam in the steam circulation system is used to heat the gaseous natural gas, turning it into a high-temperature gaseous state to improve the efficiency of on-site gas-using equipment. The temperature of the high-temperature natural gas output after heating by the steam heat exchanger is usually between 150°C and 300°C. The high-temperature natural gas is usually used for supply pipelines and industrial heating. Different industrial applications have different temperature requirements for natural gas, and the specific heating temperature depends on the actual application.

[0016] Furthermore, the output end of the pressure regulator is connected to the input end of the odorizing device through a pipeline, and the output end of the odorizing device is connected to the input end of the high-pressure natural gas transmission pipeline through a pipeline.

[0017] The beneficial effect of adopting the above further scheme is that the main function of the pressure regulator is to reduce the pressure of natural gas from a higher transmission pressure to a normal use pressure level, ensuring that the natural gas is safe when it is transported to on-site gas-using equipment; the odorizing device is used to add odorants to the natural gas. The addition of odorants can make the natural gas have a distinct odor, so that when a leak occurs, it can be discovered in time and measures can be taken, which helps to improve the safety of natural gas and reduce the risk of accidents.

[0018] Furthermore, it also includes a flow meter device, which is arranged on the pipeline between the output end of the tank truck receiving part and the natural gas output end of the steam heat exchanger.

[0019] The beneficial effect of adopting the above further scheme is that the flow meter device is used to accurately monitor the natural gas flow input by the tank truck and the natural gas flow output from the high-pressure natural gas transmission pipeline; by real-time monitoring of the flow, it can help operators understand the operating status of the system, discover abnormal conditions in time, and make corresponding adjustments and controls; at the same time, it can be connected to the data acquisition system to record flow data for accurate billing. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a flow chart of the utility model;

[0021] Figure 2 This is a working schematic diagram of the receiving part of the tank truck of the utility model;

[0022] Figure 3 This is a working schematic diagram of the circulating water type LNG gasifier of the utility model.

[0023] In the figure, 1. gas phase port of tank truck; 2. liquid phase port of tank truck; 3. pressure regulating device; 4. gaseous natural gas outlet. DETAILED DESCRIPTION

[0024] The principles and features of the present invention are described below in conjunction with examples. The examples are only used to explain the present invention and are not used to limit the scope of the present invention.

[0025] like Figure 1 and Figure 3As shown, a liquefied natural gas cold energy comprehensive utilization system includes a tank truck receiving part, an LNG vertical storage tank, an air-temperature vaporizer, a circulating water LNG vaporizer, a steam heat exchanger, a pressure regulator, an odorizing device and a high-pressure natural gas transmission pipeline, the output end of the tank truck receiving part is respectively connected to the input end of the LNG vertical storage tank, the input end of the air-temperature vaporizer and the liquid natural gas input end of the circulating water LNG vaporizer through a pipeline, the output end of the LNG vertical storage tank is respectively connected to the input end of the air-temperature vaporizer and the liquid natural gas input end of the circulating water LNG vaporizer through a pipeline, the output end of the air-temperature vaporizer and the gaseous natural gas output end of the circulating water LNG vaporizer are respectively connected to the natural gas input end of the steam heat exchanger through a pipeline. The circulating water channel of the circulating water type LNG gasifier is externally connected to the circulating cooling water system of the industrial on-site units. The cooling water used by the industrial on-site units flows into the circulating water channel of the circulating water type LNG gasifier through the cooling water pipeline. The input end and output end of the circulating water channel of the circulating water type LNG gasifier are respectively provided with an inlet water temperature sensor and an outlet water temperature sensor.

[0026] The air-temperature vaporizer and circulating water LNG vaporizer are connected in parallel, and the two sets of equipment are activated at the same time during peak gas consumption to improve efficiency; the input end of the tank truck receiving part is connected to the LNG vertical storage tank and the vaporizer respectively, which can realize the storage and gasification of LNG at the same time. While transporting liquid natural gas into the storage tank, it can also ensure uninterrupted gas supply to the site.

[0027] The circulating water LNG vaporizer uses the hotter cooling water from the industrial site units to exchange heat with liquid natural gas, so that the natural gas is heated and vaporized, and the cooling water is cooled down at the same time. The cooled cooling water flows back to the industrial site units again to cool the equipment. The water inlet temperature sensor and the water outlet temperature sensor are used to monitor the temperature of the cooling water to avoid overcooling and freezing of the cooling water.

[0028] The gaseous natural gas output end of the circulating water type LNG gasifier is connected to a first temperature sensor. When the temperature of the main pipe at the natural gas output end of the circulating water type LNG gasifier is lower than 8°C, an alarm signal is automatically sent out. When the temperature of the main pipe at the natural gas output end of the circulating water type LNG gasifier is lower than 3°C, there is a risk of freezing of the cooling water pipeline. Therefore, in addition to the automatic alarm, an instruction to cut off the emergency shut-off valve at the liquefied natural gas input end of the circulating water type LNG gasifier will be issued, that is, to stop transporting liquid natural gas into the circulating water type LNG gasifier to avoid malfunctions caused by freezing of cooling water.

[0029] The natural gas output end of the steam heat exchanger and the input end of the pressure regulator are connected through a pipeline, and the steam channel of the steam heat exchanger is externally connected to a steam circulation system. The steam heat exchanger is used to heat the low-temperature gaseous natural gas to a high-temperature gaseous state, and use the heat of the steam in the steam circulation system to heat the gaseous natural gas, turning it into a high-temperature gaseous state to improve the efficiency of on-site gas-using equipment. It is usually heated to above 200°C for industrial heating, smelting, and production to prevent insufficient combustion at a low temperature from damaging equipment or affecting production results.

[0030] The output end of the pressure regulator is connected to the input end of the odorizing device through a pipeline, and the output end of the odorizing device is connected to the input end of the high-pressure natural gas transmission pipeline through a pipeline. The main function of the pressure regulator is to reduce the pressure of natural gas from a higher transmission pressure to a normal pressure level to ensure that the natural gas is safe when it is transported to the on-site gas-using equipment; the odorizing device is used to add odorants to the natural gas. The addition of odorants can make the natural gas have a distinct smell, so that leakage can be discovered in time and measures can be taken to improve the safety of natural gas and reduce the risk of accidents.

[0031] The flow meter device is installed on the pipeline at the output end of the tank truck receiving part and the natural gas output end of the steam heat exchanger. It is used to accurately monitor the natural gas flow input by the tank truck and the natural gas flow output from the high-pressure natural gas transmission pipeline. By real-time monitoring of the flow, it can help operators understand the operating status of the system, discover abnormal situations in time, and make corresponding adjustments and controls; at the same time, it can be connected to the data acquisition system to record flow data for accurate billing.

[0032] like Figure 2 As shown, the tank truck and the input end of the tank truck receiving part are connected by a pipeline. The tank truck receiving part includes a tank truck gas phase port 1, a tank truck liquid phase port 2 and a pressure regulating device 3. The tank truck liquid phase port 2 is connected to the input end of the LNG vertical storage tank, the input end of the air-temperature vaporizer and the liquid natural gas input end of the circulating water LNG vaporizer through a pipeline; the tank truck liquid phase port 2 is also connected to the liquid natural gas inlet and outlet of the pressure regulating device 3, and the gaseous natural gas outlet 4 of the pressure regulating device 3 is connected to the tank truck gas phase port 1; the pressure regulating device 3 is a small vaporizer.

[0033] The tank truck liquid phase port 2 of the tank truck receiving part is connected to the liquid natural gas inlet and outlet of the pressure regulating device 3 through a pipeline. The pressure regulating device 3 is responsible for adjusting the pressure in the tank truck. The gaseous natural gas outlet 4 of the pressure regulating device 3 is connected to the gas phase port 1 of the tank truck, which is used to input the gasified liquid natural gas into the tank truck, increase the pressure in the tank truck, and rely on the pressure difference to pressurize the LNG into the LNG vertical storage tank; at the same time, the gaseous natural gas outlet 4 of the pressure regulating device 3 is also connected to the gaseous natural gas main, which can directly transport the gaseous natural gas to the natural gas transportation main.

[0034] The working principle of the utility model is as follows: the liquefied natural gas cold capacity comprehensive utilization system receives liquefied natural gas through the tank truck receiving part, and transports it to the LNG vertical storage tank for storage, and then the liquefied natural gas is gasified through the air-temperature gasifier and the circulating water LNG gasifier, and the steam heat exchanger is used to heat the low-temperature gaseous natural gas to a high-temperature state, and finally it is transported to the high-pressure natural gas transmission pipeline after being regulated by the pressure regulator and odorized by the odorizing device. The air-temperature gasifier and the circulating water LNG gasifier are connected in parallel to improve the gasification efficiency, and one of them can be selected for use according to actual conditions to save energy; the tank truck receiving part can realize the storage and gasification of LNG at the same time, saving the transfer time of LNG; the circulating water channel of the circulating water LNG gasifier is externally connected to the industrial field unit, and the temperature of the industrial field unit is reduced by cooling water to achieve heat dissipation and normal operation of the industrial field unit.

[0035] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A liquefied natural gas cold energy comprehensive utilization system, comprising a tank truck receiving part, an LNG vertical storage tank, an air-temperature vaporizer, a circulating water LNG vaporizer, a steam heat exchanger, a pressure regulator, an odorizing device and a high-pressure natural gas transmission pipeline, characterized in that: The output end of the tank truck receiving part is respectively connected to the input end of the LNG vertical storage tank, the input end of the air-temperature vaporizer and the liquid natural gas input end of the circulating water LNG vaporizer through pipelines, the output end of the LNG vertical storage tank is respectively connected to the input end of the air-temperature vaporizer and the liquid natural gas input end of the circulating water LNG vaporizer through pipelines, and the output end of the air-temperature vaporizer and the gaseous natural gas output end of the circulating water LNG vaporizer are respectively connected to the natural gas input end of the steam heat exchanger through pipelines; The circulating water channel of the circulating water type LNG gasifier is externally connected to the circulating cooling water system of the industrial on-site units. The cooling water used by the industrial on-site units flows into the circulating water channel of the circulating water type LNG gasifier through the cooling water pipeline. The input end and output end of the circulating water channel of the circulating water type LNG gasifier are respectively provided with an inlet water temperature sensor and an outlet water temperature sensor.

2. The liquefied natural gas cold energy comprehensive utilization system according to claim 1 is characterized in that: The gaseous natural gas output end of the circulating water type LNG gasifier is connected to a first temperature sensor. When the temperature of the main pipe at the gaseous natural gas output end of the circulating water type LNG gasifier is lower than 8°C, an alarm message is sent out; when the temperature of the main pipe at the gaseous natural gas output end of the circulating water type LNG gasifier is lower than 3°C, a control instruction to cut off the circulating water type LNG gasifier is sent out.

3. The liquefied natural gas refrigeration comprehensive utilization system according to claim 1 is characterized in that: The tank truck and the input end of the tank truck receiving part are connected through a pipeline. The tank truck receiving part includes a tank truck gas phase port, a tank truck liquid phase port and a pressure regulating device. The tank truck liquid phase port is connected to the input end of the LNG vertical storage tank, the input end of the air-temperature vaporizer and the liquid natural gas input end of the circulating water LNG vaporizer through a pipeline; the tank truck liquid phase port is also connected to the liquid natural gas inlet and outlet of the pressure regulating device, and the gaseous natural gas outlet of the pressure regulating device is connected to the tank truck gas phase port; the pressure regulating device is a small vaporizer.

4. The liquefied natural gas refrigeration comprehensive utilization system according to claim 1 is characterized in that: The natural gas output end of the steam heat exchanger and the input end of the pressure regulator are connected through a pipeline.

5. The liquefied natural gas refrigeration comprehensive utilization system according to claim 4 is characterized in that: The steam channel of the steam heat exchanger is externally connected to a steam circulation system.

6. The liquid natural gas refrigeration comprehensive utilization system according to claim 5 is characterized in that: The output end of the pressure regulator is connected to the input end of the odorizing device through a pipeline, and the output end of the odorizing device is connected to the input end of the high-pressure natural gas transmission pipeline through a pipeline.

7. The liquid natural gas refrigeration comprehensive utilization system according to claim 3 is characterized in that: It also includes a flow meter device, which is arranged on the pipelines at the output end of the tank truck receiving part and the natural gas output end of the steam heat exchanger.

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