Material switching device for low-temperature freezing tank

Abstract

The utility model relates to a low-temperature freezing tank material switching device, which comprises a low-temperature freezing storage tank for storing a first material, and further comprises a feeding pipeline, a gas phase output pipeline, a heating device and a compressor, the feeding pipeline is connected with the low-temperature freezing storage tank, the outlet end of the feeding pipeline extends to the bottom of the low-temperature freezing storage tank, and the gas phase output pipeline is connected with the heating device. The inlet end of the feeding pipeline is used for being connected with a tank car for storing a second material, the heating device is arranged on the feeding pipeline and is used for heating and vaporizing the second material from the tank car, the gas phase output pipeline is connected with the top of the low-temperature freezing storage tank, the compressor is arranged on the gas phase output pipeline, and the gas phase output pipeline is connected with the top of the low-temperature freezing storage tank. And the pressurizing device is used for pressurizing the mixed gas from the low-temperature freezing storage tank and then conveying the pressurized mixed gas to the downstream. The device has the advantages that the problem that materials cannot be recycled due to the fact that non-condensable gas is carried in mixed gas in the replacement process can be effectively solved, and then economic losses and potential safety hazards are reduced.

Description

Technical Field

[0001] The utility model relates to the technical field of chemical equipment, in particular to a low-temperature freezing tank material switching device. Background Art

[0002] At present, petrochemical plants are mostly equipped with large cryogenic freezing tanks to store raw materials or products due to production needs. Cryogenic freezing tanks are generally double-containment or full-containment storage tanks, such as: used to store cryogenic LNG, cryogenic ethane, cryogenic propane, cryogenic ethylene storage tanks, etc. In order to take into account the versatility of the storage tank, multiple material storage functions are considered during the design. Due to market conditions or production needs, it will be considered to replace the materials in the storage tank, that is, to convert storage medium A into storage medium B, such as switching from storing cryogenic propane to storing cryogenic ethane. The method of switching the above materials in the storage tank in the industry is basically: first gasify the propane and send it to the downstream device. When the propane liquid phase is completely converted into the gas phase, nitrogen is used to replace the inner and outer tanks. The mixed gas after replacement cannot be recovered due to the high content of non-condensable gas (nitrogen), and can only be depressurized to the flare. After the propane gas phase replacement is qualified, the nitrogen is replaced with gaseous ethane. The replacement mixed gas cannot be recovered due to the high content of non-condensable gas (nitrogen), and can only be depressurized to the flare.

[0003] The material switching device of the above-mentioned storage tank has certain shortcomings: during the nitrogen replacement process, due to the relatively high content of non-condensable gas (nitrogen) in the mixed gas, the propane gas phase and the ethane gas phase cannot be effectively recovered, and can only be discharged by flaring, which not only causes waste of resources, environmental pollution and other adverse effects, but also during the discharge of a large amount of combustible gas, it will also bring safety hazards due to incomplete combustion and other reasons.

[0004] Therefore, the existing low-temperature freezing tank material switching device needs to be further improved. Utility Model Content

[0005] The technical problem to be solved by the utility model is to provide a low-temperature freezing tank material switching device which can effectively improve the problem that materials cannot be recovered due to non-condensable gas entrained in the mixed gas during the replacement process, thereby reducing economic losses and safety hazards.

[0006] The technical solution adopted by the utility model to solve the above-mentioned technical problems is: a low-temperature freezing tank material switching device, including a low-temperature freezing tank for storing a first material, and also including a feed pipeline, a gas phase output pipeline, a heating device and a compressor. The feed pipeline is connected to the low-temperature freezing tank, and the outlet end extends to the bottom of the low-temperature freezing tank. The inlet end of the feed pipeline is used to be connected to a tank truck storing a second material. The heating device is arranged on the feed pipeline to heat and vaporize the second material from the tank truck. The gas phase output pipeline is connected to the top of the low-temperature freezing tank. The compressor is arranged on the gas phase output pipeline to pressurize the mixed gas from the low-temperature freezing tank and send it downstream.

[0007] In order to facilitate the cutting out and maintenance of the compressor, the gas phase output pipeline includes a first output pipeline and a second output pipeline arranged in parallel, and the compressor is arranged on the first output pipeline and the second output pipeline.

[0008] Generally, the heating device can adopt various existing heaters in the factory area that can heat the materials in the feed pipeline. Preferably, the heating device is a vaporizer.

[0009] As an improvement, it also includes a liquid phase output pipeline connected to the low temperature freezing storage tank, and a control valve for controlling the on-off is arranged on the liquid phase output pipeline. When different materials are replaced, the control valve controls the liquid phase output pipeline to be closed.

[0010] As an improvement, the first material and the second material are any two of LNG, ethane, propane and ethylene. Preferably, the first material is propane and the second material is ethane.

[0011] Compared with the prior art, the advantages of the utility model are: the low-temperature freezing tank material switching device of this embodiment can utilize a heating device to heat and vaporize the second material from, for example, a tank truck. After being heated into a gas phase, it enters the bottom of the low-temperature freezing storage tank and is taken out from the top of the tank together with the gas phase of the first material. After being pressurized by a compressor, it is supplied to downstream devices as fuel gas or raw materials. Compared with the traditional method of using non-condensable gas (such as nitrogen) for replacement, this material switching device effectively improves the problem of being unable to recover materials due to the entrainment of non-condensable gas in the mixed gas during the replacement process, thereby reducing economic losses and safety hazards of the low-temperature freezing tank material switching device. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 It is a structural schematic diagram of a low-temperature freezing tank material switching device according to an embodiment of the utility model. DETAILED DESCRIPTION

[0013] The present invention will be described in further detail below in conjunction with the accompanying drawings.

[0014] In the specification and claims of the present invention, terms indicating directions, such as "front", "rear", "up", "down", "left", "right", "side", "top", "bottom", etc., are used to describe various exemplary structural parts and elements of the present invention, but these terms are used here only for the purpose of convenience of description and are determined based on the exemplary orientations shown in the accompanying drawings. Since the embodiments disclosed in the present invention can be arranged in different directions, these terms indicating directions are only used as explanations and should not be regarded as limitations. For example, "up" and "down" are not necessarily limited to directions opposite to or consistent with the direction of gravity.

[0015] Figure 1 The figure shows a preferred embodiment of the low-temperature freezing tank material switching device of the utility model. The low-temperature freezing tank material switching device comprises a low-temperature freezing storage tank 10 , a feed pipeline 11 , a gas phase output pipeline 12 , a heating device 13 and a compressor 14 .

[0016] The cryogenic storage tank 10 is used to store one of cryogenic LNG, cryogenic ethane, cryogenic propane, and cryogenic ethylene. For example, the current storage material (i.e., the first material) of the cryogenic storage tank 10 is cryogenic propane, and cryogenic ethane (i.e., the second material) needs to be replaced.

[0017] The feed pipeline 11 is connected to the cryogenic freezing storage tank 10. Specifically, the feed pipeline 11 can be the original pipeline of the cryogenic freezing storage tank 10 for conveying materials to the cryogenic freezing storage tank 10 (generally connected to the pipeline for unloading materials at the dock). In order to ensure the replacement effect and replacement efficiency, the original feed pipeline 11 can be additionally provided with a section of pipeline extending to the bottom of the cryogenic freezing storage tank 10, that is, the outlet end of the feed pipeline 11 used for replacement is located at the bottom of the cryogenic freezing storage tank 10. The inlet end of the feed pipeline 11 can be used to be connected to the tank truck 17 storing ethane (i.e., the second material).

[0018] The heating device 13 of this embodiment is arranged on the feed pipeline 11, and preferably a vaporizer is used to heat and vaporize the ethane from the tank truck 17.

[0019] The gas phase output pipeline 12 is connected to the top of the cryogenic freezing storage tank 10, and is used to discharge the mixed gas in the tank out of the tank during the ethane and propane replacement process. The compressor 14 is arranged on the gas phase output pipeline 12, and is used to pressurize the mixed bubble point gas from the cryogenic freezing storage tank 10 and send it downstream for use as fuel gas or raw material. In order to facilitate the cutting out of the compressor 14 for maintenance, the gas phase output pipeline 12 of this embodiment includes a first output pipeline 121 and a second output pipeline 122 arranged in parallel, and the first output pipeline 121 and the second output pipeline 122 are both provided with a compressor 14.

[0020] The low temperature freezing tank material switching device also includes a liquid phase output pipeline 15 connected to the low temperature freezing storage tank 10. The inlet end of the liquid phase output pipeline 15 is located at the bottom of the low temperature freezing storage tank 10, and can be used to pressurize the replaced ethane material and send it to the downstream device. A control valve 16 for controlling the on-off is provided on the liquid phase output pipeline 15. When the ethane and propane materials are replaced, the control valve 16 controls the liquid phase output pipeline 15 to be closed.

[0021] The low-temperature freezing tank material switching device of this embodiment can utilize the heating device 13 to heat and vaporize the second material from, for example, a tank truck 17. After being heated into a gas phase, the second material enters the bottom of the low-temperature freezing storage tank 10 and is taken out from the top of the tank together with the gas phase of the first material. After being pressurized by the compressor 14, the material switching device is supplied to the downstream device as fuel gas or raw material. Compared with the traditional method of using non-condensable gas (such as nitrogen) for replacement, this material switching device effectively improves the problem of being unable to recover the material due to the entrainment of non-condensable gas in the mixed gas during the replacement process, thereby reducing economic losses and safety hazards of the low-temperature freezing tank material switching device.

Claims

1. A low-temperature freezing tank material switching device, comprising a low-temperature freezing tank (10) for storing a first material, characterized in that: It also includes a feed pipeline (11), a gas phase output pipeline (12), a heating device (13) and a compressor (14). The feed pipeline (11) is connected to the low-temperature freezing storage tank (10), and the outlet end extends to the bottom of the low-temperature freezing storage tank (10). The inlet end of the feed pipeline (11) is used to be connected to a tank truck (17) storing a second material. The heating device (13) is arranged on the feed pipeline (11) and is used to heat and vaporize the second material from the tank truck (17). The gas phase output pipeline (12) is connected to the top of the low-temperature freezing storage tank (10). The compressor (14) is arranged on the gas phase output pipeline (12) and is used to pressurize the mixed gas from the low-temperature freezing storage tank (10) and send it downstream.

2. The low-temperature freezing tank material switching device according to claim 1 is characterized in that: The gas phase output pipeline (12) comprises a first output pipeline (121) and a second output pipeline (122) which are arranged in parallel, and the compressor (14) is disposed on both the first output pipeline (121) and the second output pipeline (122).

3. The low-temperature freezing tank material switching device according to claim 1 is characterized in that: The heating device (13) is a vaporizer.

4. The low-temperature freezing tank material switching device according to claim 1, characterized in that: It also comprises a liquid phase output pipeline (15) connected to the low-temperature freezing storage tank (10), and a control valve (16) for controlling on and off is provided on the liquid phase output pipeline (15).

5. The low-temperature freezing tank material switching device according to any one of claims 1 to 4, characterized in that: The first material and the second material are any two of LNG, ethane, propane and ethylene.

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