Device for producing liquid air

Abstract

The embodiment of the utility model discloses equipment for producing liquid air. The equipment comprises an air filter, a first air compressor, an air pre-cooler, a purification system, a second air compressor, a booster expansion turbine system, a main heat exchanger and a liquid air collection system which are connected in sequence, wherein gas at the compression end of the booster expansion turbine system is conducted to the main heat exchanger to absorb the cold energy to obtain liquid air, and the liquid air is conducted to the liquid air collecting system. According to the technical scheme, after raw material air is filtered, compressed, pre-cooled and purified, the second air compressor and the compression end of the booster expansion turbine system are sequentially used for pressurizing the air, the expansion end of the booster expansion turbine system generates cold energy, and the pressurized air absorbs the cold energy in the main heat exchanger to obtain liquid air; and then low-temperature liquid air is separated out and fed into a liquid air storage tank, and preparation of the liquid air is achieved. And meanwhile, part of nitrogen and liquid nitrogen can be co-produced, and the user requirements are met.

Description

Technical Field

[0001] The present disclosure relates to the technical field of liquid air equipment, and in particular to equipment for producing liquid air. Background Art

[0002] Liquid air (or simply air liquid) is a light blue liquid made by liquefying air. At present, there is no equipment on the market that specializes in producing air liquid. Liquid air is only an intermediate product of air separation equipment. With the increasing demand for air liquid products, it is urgent to provide a device that simplifies the air separation process and specializes in producing air liquid. Summary of the invention

[0003] In order to solve the problems in the related art, an embodiment of the present disclosure provides a device for producing liquid air.

[0004] An embodiment of the present disclosure provides an apparatus for producing liquid air, comprising: an air filter, a first air compressor, an air precooler, a purification system, a second air compressor, a booster turbine expander system, a main heat exchanger and a liquid air collection system connected in sequence; wherein the gas at the compression end of the booster turbine expander system is conducted to the main heat exchanger to absorb cold energy to obtain liquid air, and then conducted to the liquid air collection system.

[0005] Optionally, the first air compressor is a turbine compressor; the second air compressor is a circulating air boost compressor.

[0006] Optionally, the purification system includes a water vapor separator and a molecular sieve adsorption system.

[0007] Optionally, the molecular sieve adsorption system comprises two molecular sieve adsorbers and a heater, wherein the heaters are respectively connected to the two molecular sieve adsorbers, and the heater is connected to the main heat exchanger.

[0008] Optionally, the molecular sieve adsorption system is also connected to the expansion end of the booster turbine expander system.

[0009] Optionally, the device further comprises an instrument gas system connected to the molecular sieve adsorption system.

[0010] Optionally, the second air compressor is also connected to the main heat exchanger.

[0011] Optionally, the booster turbine expander system includes a high temperature expander and a low temperature expander;

[0012] The second air compressor, the compression end of the high-temperature expander, and the compression end of the low-temperature expander are connected in sequence.

[0013] Optionally, the liquid air collection system includes a gas-liquid separation tank and a supercooling box.

[0014] Optionally, the device further comprises a liquid air storage tank connected to the supercooling box.

[0015] Optionally, the equipment further comprises a distillation tower connected to the gas-liquid separation tank and the molecular sieve adsorption system.

[0016] The technical solution provided by the embodiments of the present disclosure may have the following beneficial effects:

[0017] The equipment for producing liquid air provided by the embodiment of the present disclosure includes: an air filter, a first air compressor, an air precooler, a purification system, a second air compressor, a booster turbine expander system, a main heat exchanger and a liquid air collection system connected in sequence; wherein, the gas at the compression end of the booster turbine expander system is conducted to the main heat exchanger to absorb cold to obtain liquid air, and then conducted to the liquid air collection system. In the above technical scheme, after filtering, compressing, precooling and purifying the raw air, the air is pressurized by the second air compressor and the compression end of the booster turbine expander system in sequence, and the expansion end of the booster turbine expander system generates cold. The pressurized air absorbs cold in the main heat exchanger to obtain liquid air, and then the low-temperature liquid air is separated and sent to the liquid air storage tank, thereby realizing the preparation of liquid air. At the same time, a part of nitrogen and liquid nitrogen can also be co-produced to meet user needs.

[0018] It is to be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Other features, objectives and advantages of the present disclosure will become more apparent through the following detailed description of non-limiting embodiments in conjunction with the accompanying drawings. In the accompanying drawings:

[0020] Figure 1 A schematic diagram showing the structure of a device for producing liquid air according to an embodiment of the present disclosure;

[0021] Figure 2 A first sub-flow chart of producing liquid air according to an embodiment of the present disclosure is shown;

[0022] Figure 3 A second sub-flow chart showing production of liquid air according to an embodiment of the present disclosure is shown;

[0023] Figure 4 A third sub-flow chart for producing liquid air according to an embodiment of the present disclosure is shown;

[0024] Figure 5 A fourth sub-flow chart for producing liquid air according to an embodiment of the present disclosure is shown;

[0025] Figure 6 A fifth sub-flow chart for producing liquid air according to an embodiment of the present disclosure is shown;

[0026] Figure 7 A sixth sub-flow chart for producing liquid air according to an embodiment of the present disclosure is shown. DETAILED DESCRIPTION

[0027] Hereinafter, exemplary embodiments of the present disclosure will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily implement them. In addition, for the sake of clarity, parts not related to the description of the exemplary embodiments are omitted in the accompanying drawings.

[0028] In addition, persons of ordinary skill in the art will appreciate that the drawings provided herein are for illustration purposes and are not necessarily drawn to scale.

[0029] Unless the context clearly requires otherwise, words such as “include”, “including” and the like in the specification should be interpreted as including rather than being exclusive or exhaustive; that is, as meaning “including but not limited to”.

[0030] In the description of the present disclosure, it should be understood that the terms "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance. In addition, in the description of the present disclosure, unless otherwise specified, the meaning of "plurality" is two or more.

[0031] Unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in this disclosure can be understood according to specific circumstances.

[0032] It should also be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present disclosure may be combined with each other. The present disclosure will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0033] like Figures 1 to 7 As shown, the equipment for producing liquid air includes: an air filter 11, a first air compressor 12, an air precooler 13, a purification system, a second air compressor 18, a booster turbine expander system, a main heat exchanger 23 and a liquid air collection system connected in sequence; wherein, the gas at the compression end of the booster turbine expander system is conducted to the main heat exchanger 23 to absorb cold energy to obtain liquid air, and then conducted to the liquid air collection system.

[0034] According to an embodiment of the present disclosure, the first air compressor 12 is a turbine compressor having a three-stage cooler; and the second air compressor 18 is a circulating air boost compressor.

[0035] According to an embodiment of the present disclosure, the purification system includes a water vapor separator 14 and a molecular sieve adsorption system.

[0036] According to an embodiment of the present disclosure, the molecular sieve adsorption system includes two molecular sieve adsorbers 15 , 16 and a heater 17 , wherein the heater 17 is connected to the two molecular sieve adsorbers 15 , 16 , respectively, and the heater 17 is connected to the main heat exchanger 23 .

[0037] According to an embodiment of the present disclosure, the molecular sieve adsorption system is also connected to the expansion end of the booster turbine expander system.

[0038] According to an embodiment of the present disclosure, the device further includes an instrument gas system connected to the molecular sieve adsorption system.

[0039] According to an embodiment of the present disclosure, the second air compressor 18 is also connected to the main heat exchanger 23 .

[0040] According to an embodiment of the present disclosure, the booster turbine expander system includes a high-temperature expander 20 and a low-temperature expander 19; the second air compressor 18, the compression end of the high-temperature expander 20, and the compression end of the low-temperature expander 19 are connected in sequence.

[0041] According to an embodiment of the present disclosure, the liquid air collection system includes a gas-liquid separation tank 24 and a supercooling box 25 .

[0042] According to an embodiment of the present disclosure, the device further includes a liquid air storage tank connected to the supercooling box 25 .

[0043] According to an embodiment of the present disclosure, the device further comprises a fractionation tower A2 connected to the gas-liquid separation tank 24 and the molecular sieve adsorption system.

[0044] Please refer to Figure 2 , Figure 3 As shown, the water vapor separator 14 is connected to the two molecular sieve adsorbers 15 and 16 through the pipeline GA-1102, the two molecular sieve adsorbers 15 and 16 are connected to the air filter 11 through the pipeline GA-2001, and are also connected to the second air compressor 18 through the pipeline GA-101, connected to the expansion end of the high-temperature expander 20 through the pipeline GA-1271, connected to the instrument gas system through the pipeline GA-2013, connected to the main heat exchanger 23 through the pipeline GA-1251, and connected to the distillation tower A2 through the pipeline GA-201.

[0045] Please refer to Figure 4 , Figure 5 , Figure 6 As shown, the second air compressor 18 is connected to the compression end of the high-temperature expander 20 through the pipeline GA-121, is connected to the bearings of the high-temperature expander 20 and the low-temperature expander 19 through the pipeline GA-141, and is connected to the main heat exchanger 23 through the pipelines GA-111 and GA-131.

[0046] The expansion end of the high temperature expander 20 is connected to the main heat exchanger 23 through pipelines GA-405 and GA-407; the expansion end of the low temperature expander 19 is connected to the main heat exchanger 23 through pipelines GA-455 and GA-457. The compression end of the high temperature expander 20 is connected to a first cooler 22 and then connected to the compression end of the low temperature expander 19, and the compression end of the low temperature expander 19 is connected to a second cooler 21 and then connected to the main heat exchanger 23 through pipeline GA-453.

[0047] After the compressed gas in the pipeline GA-453 absorbs cold energy in the main heat exchanger 23, high-pressure liquid air is obtained at the bottom of the main heat exchanger 23, and is transported to the gas-liquid separation tank 24 through the pipeline LA-01. A pressure reducing valve is provided on the pipeline LA-01 to reduce the pressure of the liquid air. The liquid air in the gas-liquid separation tank 24 is further cooled by the cold box 25 to obtain a liquid air product, which is transported to the liquid air storage tank for storage. The gas-liquid separation tank 24 is also connected to the fractionation tower A2 through the pipeline GA-202.

[0048] It should be noted that Figures 2 to 7 The directions of the boxes from P1 to P6 in the figure represent the material flow direction, and the words P1 to P6 represent the referenced figure numbers, for example Figure 2 The right direction P2 in the figure indicates the material flow direction Figure 3 The molecular sieve adsorption system in Figure 3 The left P5 in the figure indicates that the material comes from Figure 6 The main heat exchanger in.

[0049] The overall process of the equipment for producing liquid air provided by the embodiment of the present disclosure is as follows:

[0050] After the dust and mechanical impurities are removed from the raw air in the air filter, it enters the turbine compressor and is intermediate-cooled by the intercooler to compress the air to about 0.55MPa (A). After being cooled by the final cooler, it enters the air precooler to cool down to 5-10℃ and separate the free water.

[0051] The air from the air precooler enters the molecular sieve adsorber, which is a vertical double-layer bed used to remove moisture, carbon dioxide and some hydrocarbons in the air, so as to obtain clean and dry air. The two molecular sieve adsorbers are used alternately, that is, one adsorber absorbs impurities and the other adsorber is regenerated with high-temperature waste nitrogen.

[0052] The purified air and the air from the main heat exchanger enter the circulating air booster compressor to increase the air pressure. Part of the pressurized air is pressurized again by the high-temperature expander, the high-temperature expander boosting end driven by the low-temperature expander, and the low-temperature expander boosting end in turn. The rest of the air enters the main heat exchanger for heat exchange, enters the expansion end of the high-temperature expander for expansion, and then returns to the main heat exchanger.

[0053] The circulating air from the circulating air booster compressor driven by the high and low temperature expanders is cooled by the low-pressure air from the return flow and the return gas from the high and low temperature expanders through the main heat exchanger. The circulating air is cooled to a certain temperature and most of it is extracted from the lower part of the main heat exchanger to enter the low temperature expander for expansion; the rest continues to be cooled, liquefied, and supercooled in the main heat exchanger, and finally throttled and sent to the gas-liquid separation tank. The expanded air from the low temperature expander and the gas from the gas-liquid separation tank are combined into one stream and enter the main heat exchanger as a cold source for the return flow. The low-temperature liquid air is separated from the gas-liquid separation tank, and is further cooled in the supercooling box and sent to the liquid air storage tank.

[0054] Part of the reflux air is reheated in the main heat exchanger and then leaves the cold box, enters the electric heater for heating, and serves as the regeneration gas for the molecular sieve adsorber.

[0055] The above process is a liquid air process of normal temperature molecular sieve adsorption purification, air circulation boosting (circulating air boosting compressor), high and low temperature boosting turbine expander combined refrigeration, and high-efficiency plate-fin heat exchanger (main heat exchanger). It is one of the special liquid air production processes. Molecular sieve adsorption purification is used to improve the reliability of system operation. High and low temperature expander refrigeration is used to obtain a larger unit enthalpy drop; air circulation boosting expansion is used to reduce energy consumption.

[0056] In addition, combined Figure 3 , Figure 6 as well as Figure 7 As shown, the equipment for generating liquid air provided by the present disclosure can generate a part of nitrogen and liquid nitrogen at the same time to meet user needs. The specific process is as follows: liquid air is sent to the top of the fractionation tower A2 through the regulating valve A1 as a cold source and raw material, and at the same time, air is sent to the main heat exchanger A4 of the fractionation tower through the regulating valve A6, and is sent to the bottom of the fractionation tower A2 after being cooled. After distillation in the fractionation tower A2, oxygen-rich liquid air is generated at the bottom of the fractionation tower A2, and is sent to the evaporation end of the condenser evaporator A3 after being cooled by the cold heat exchanger A5, and its pressure can be adjusted by the regulating valve A7. The oxygen-rich liquid air becomes oxygen-rich air after evaporation in the condenser evaporator A3, and is sent out at the top of the condenser evaporator A3, and is sent out of the cold box after heat exchange to room temperature through the cold heat exchanger A5 and the main heat exchanger A4 of the fractionation tower.

[0057] Part of the nitrogen produced at the top of the fractionation tower A2 enters the condensation end of the condensation heat exchanger A3, where it is condensed into liquid nitrogen. Part of the liquid nitrogen is sent out of the cold box through the regulating valve A8 and stored in the storage tank, while the other part of the liquid nitrogen returns to the top of the fractionation tower A2 as reflux liquid through the regulating valve A9. The other part of the nitrogen enters the subcooling heat exchanger A5 and the main heat exchanger A4 of the fractionation tower through the regulating valve A10, and is heat-exchanged to room temperature before being sent out of the cold box as a product.

[0058] The output of liquid nitrogen and nitrogen gas can be adjusted by regulating valve A8 and regulating valve A10 respectively. When mainly producing liquid nitrogen products, more cooling capacity is needed, so regulating valve A1 needs to be opened to allow more liquid air to enter fractionation tower A2 to provide cooling capacity, so as to produce more liquid nitrogen products. When mainly producing nitrogen gas products, regulating valve A1 is appropriately closed, and regulating valve A6 is opened to allow more air to enter fractionation tower A2. Since less liquid air enters fractionation tower A2, less cooling capacity is entered, and its product is mainly nitrogen. If necessary, regulating valve A8 can be closed to make its product completely nitrogen.

[0059] The above description is only a preferred embodiment of the present disclosure and an explanation of the technical principles used. Those skilled in the art should understand that the scope of the invention involved in the present disclosure is not limited to the technical solution formed by a specific combination of the above technical features, but should also cover other technical solutions formed by any combination of the above technical features or their equivalent features without departing from the inventive concept. For example, the above features are replaced with the technical features with similar functions disclosed in the present disclosure (but not limited to) by each other.

Claims

1. A device for producing liquid air, characterized in that: include: An air filter, a first air compressor, an air precooler, a purification system, a second air compressor, a booster turbine expander system, a main heat exchanger and a liquid air collection system are connected in sequence; wherein the gas at the compression end of the booster turbine expander system is conducted to the main heat exchanger to absorb cold energy to obtain liquid air, and then conducted to the liquid air collection system.

2. The equipment for producing liquid air according to claim 1, characterized in that: The first air compressor is a turbine compressor; the second air compressor is a circulating air booster compressor.

3. The equipment for producing liquid air according to claim 1, characterized in that: The purification system includes a water vapor separator and a molecular sieve adsorption system.

4. The equipment for producing liquid air according to claim 3, characterized in that: The molecular sieve adsorption system comprises two molecular sieve adsorbers and a heater, wherein the heaters are respectively connected to the two molecular sieve adsorbers, and the heater is connected to the main heat exchanger.

5. The equipment for producing liquid air according to claim 3, characterized in that: The molecular sieve adsorption system is also connected to the expansion end of the booster turbine expander system.

6. The equipment for producing liquid air according to claim 3, characterized in that: Also included is an instrument gas system connected to the molecular sieve adsorption system.

7. The equipment for producing liquid air according to claim 1, characterized in that: The second air compressor is also connected to the main heat exchanger.

8. The equipment for producing liquid air according to claim 1, characterized in that: The booster turbine expander system includes a high-temperature expander and a low-temperature expander; The second air compressor, the compression end of the high-temperature expander, and the compression end of the low-temperature expander are connected in sequence.

9. The equipment for producing liquid air according to claim 3, characterized in that: The liquid air collection system comprises a gas-liquid separation tank and a supercooling box.

10. The equipment for producing liquid air according to claim 9, characterized in that: It also includes a distillation tower connected to the gas-liquid separation tank and the molecular sieve adsorption system.

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