Pre-cooling system and air separation equipment

Abstract

The embodiment of the utility model discloses a precooling system and an air separation plant, and the precooling system comprises a heat exchanger which is arranged between an air compressor and a molecular sieve system and is used for heat exchange between an air separation raw material and gas discharged from an air separation cold box so as to precool the air separation raw material. According to the technical scheme, the heat exchanger is arranged between the air compressor and the molecular sieve system to replace equipment such as an air cooling tower and a water cooling tower, gas from the air separation cold box can directly exchange heat with air separation raw materials in the heat exchanger, the air separation process is optimized, resource waste caused by indirect heat exchange is avoided, and precooling of the air separation raw materials is achieved. Meanwhile, the heat exchanger has the advantage of small size, and can be stacked with the molecular sieve system, so that the occupied area of the pre-cooling system in the traditional process is effectively reduced.

Description

Technical Field

[0001] The present disclosure relates to the technical field of air separation equipment, and in particular to a precooling system and an air separation equipment. Background Art

[0002] The air precooling system is a system used to precool and wash the raw air before it enters the air separation unit or molecular sieve adsorber. It includes air cooling towers, water cooling towers and other equipment. The precooling principle of the air precooling system is to use the water in the air cooling tower to cool the washed air, use the water cooling tower to cool the water and supply the water to the air cooling tower. In the prior art, the cooling water is provided by the air separation cold box to avoid the waste of cooling. However, the utilization of this cooling capacity requires the provision of excess water to absorb the cooling capacity, and then provide it to the water cooling tower, which is complicated and wastes resources. Summary of the invention

[0003] In order to solve the problems in the related art, the embodiments of the present disclosure provide a precooling system and an air separation device.

[0004] In a first aspect, an embodiment of the present disclosure provides a precooling system, comprising: a heat exchanger, arranged between an air compressor and a molecular sieve system, for exchanging heat between air separation raw materials and gas exiting an air separation cold box, so as to precool the air separation raw materials.

[0005] According to an embodiment of the present disclosure, the precooling system further includes: a first gas-liquid separation tank, which is respectively connected to the heat exchanger and the molecular sieve system.

[0006] According to an embodiment of the present disclosure, the precooling system further includes: a second gas-liquid separation tank, which is respectively connected to the heat exchanger and the air separation cold box.

[0007] According to an embodiment of the present disclosure, the precooling system further includes: a second gas-liquid separation tank, which is respectively connected to the first gas-liquid separation tank, the heat exchanger, and the air separation cold box.

[0008] According to an embodiment of the present disclosure, the molecular sieve system is connected to the air separation cold box.

[0009] According to an embodiment of the present disclosure, the molecular sieve system includes two molecular sieves that are switched for use and an electric heater.

[0010] According to an embodiment of the present disclosure, the precooling system has a cold box shell on the outside.

[0011] According to an embodiment of the present disclosure, the heat exchanger and the molecular sieve system are stacked and arranged in the cold box shell.

[0012] In a second aspect, an embodiment of the present disclosure provides an air separation device, comprising a precooling system as described in any one of the first aspects.

[0013] The technical solution provided by the embodiments of the present disclosure may have the following beneficial effects:

[0014] The precooling system provided by the embodiment of the present disclosure includes: a heat exchanger, which is arranged between the air compressor and the molecular sieve system, and is used for heat exchange between the air separation raw material and the gas after exiting the air separation cold box, so as to precool the air separation raw material. The above technical scheme replaces the air cooling tower, water cooling tower and other equipment by arranging a heat exchanger between the air compressor and the molecular sieve system. The gas from the air separation cold box can directly exchange heat with the air separation raw material in the heat exchanger, thereby optimizing the air separation process, avoiding the waste of resources caused by indirect heat exchange, and realizing the precooling of the air separation raw material. At the same time, the heat exchanger has the advantage of small size, and can also be stacked with the molecular sieve system, effectively reducing the footprint of the precooling system in the traditional process.

[0015] 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

[0016] 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:

[0017] Figure 1 A schematic structural diagram of a precooling system according to an embodiment of the present disclosure is shown. DETAILED DESCRIPTION

[0018] 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.

[0019] 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.

[0020] 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”.

[0021] 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.

[0022] 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.

[0023] 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.

[0024] Figure 1 A schematic structural diagram of a precooling system according to an embodiment of the present disclosure is shown.

[0025] like Figure 1 The precooling system includes: a heat exchanger E1, which is arranged between the air compressor (not shown in the figure) and the molecular sieve system, and is used for heat exchange between the air separation raw material and the gas after leaving the air separation cold box to precool the air separation raw material.

[0026] The precooling system provided by the present invention replaces equipment such as air cooling towers and water cooling towers by arranging a heat exchanger between the air compressor and the molecular sieve system. The gas from the air separation cold box can directly exchange heat with the air separation raw materials in the heat exchanger, thereby optimizing the air separation process, avoiding the waste of resources caused by indirect heat exchange, and realizing the precooling of the air separation raw materials.

[0027] According to an embodiment of the present disclosure, the molecular sieve system includes two molecular sieves MS1301, MS1302 and an electric heater H001 for switching use. The molecular sieve system also includes valves V1301, V1302, V1303, V1304, V1305, V1306, V1307, V1308, V1309 and V1310. A start-stop button is also provided on the electric heater H001. In the embodiment of the present disclosure, the pressurized air separation raw material delivered from the air compressor is lowered in temperature after heat exchange in the heat exchanger E1, and then enters the molecular sieve system to remove impurities. In the two molecular sieves of the present disclosure, when one of them adsorbs impurities, the other regenerates the molecular sieve, and adsorption and regeneration are performed alternately, thereby switching use, and the specific content of the prior art can be referred to. In the subsequent embodiments, the present disclosure only takes molecular sieve MS1301 for adsorption and molecular sieve MS1302 for regeneration as an example for schematic description.

[0028] According to an embodiment of the present disclosure, the precooling system further includes: a first gas-liquid separation tank C1, which is connected to the heat exchanger E1 and the molecular sieve system respectively. After precooling, the air separation raw material enters the first gas-liquid separation tank C1, the moisture in the air separation raw material remains in the first gas-liquid separation tank C1, and the gas enters the molecular sieve system for adsorption.

[0029] According to an embodiment of the present disclosure, the precooling system further includes: a second gas-liquid separation tank C2, which is connected to the heat exchanger E1 and the air separation cold box respectively. The nitrogen from the air separation cold box is a dry gas with hygroscopicity, and first enters the second gas-liquid separation tank C2 to contact the liquid in the tank. After the nitrogen absorbs moisture, the temperature drops slightly, and then enters the heat exchanger E1 for heat exchange, so that the outlet temperature of the air separation raw material stream in the heat exchanger E1 is reduced.

[0030] According to an embodiment of the present disclosure, the precooling system further includes: a second gas-liquid separation tank C2, which is respectively connected to the first gas-liquid separation tank C1, a heat exchanger, and an air separation cold box. In the disclosed method, the second gas-liquid separation tank C2 is also connected to the first gas-liquid separation tank C1, so that the liquid in the first gas-liquid separation tank C1 can flow into the second gas-liquid separation tank C2.

[0031] According to an embodiment of the present disclosure, the molecular sieve system is connected to the air separation cold box.

[0032] According to an embodiment of the present disclosure, the precooling system has a cold box shell on the outside.

[0033] According to an embodiment of the present disclosure, the heat exchanger and the molecular sieve system are stacked and arranged in the cold box shell. The heat exchanger has the advantage of small size, and the stacked arrangement with the molecular sieve system can effectively reduce the floor space occupied by the precooling system in the traditional process.

[0034] The embodiments of the present disclosure also provide an air separation device, comprising a precooling system as described in any one of the above items.

[0035] Combine the following Figure 1Further explanation of the precooling purification process of the air separation equipment disclosed in the present invention: after the air separation raw material enters the heat exchanger E1 for heat exchange, it enters the first gas-liquid separation tank C1 for gas-liquid separation, the water in the air separation raw material remains in the first gas-liquid separation tank C1, the gas of the air separation raw material enters the molecular sieve MS1301 through the valve V1307, and after purification, it enters the air separation cold box through the valve V1301; the liquid in the first gas-liquid separation tank C1 flows into the second gas-liquid separation tank C2 through the valve V901, and the first stream from the air separation The nitrogen in the cold box N2 is hygroscopic, and the liquid in the second gas-liquid separation tank C2 can be discharged into the air along with the gas. At the same time, the nitrogen absorbs moisture and is discharged after heat exchange with the air separation raw material from the air separation cold box O2 in the heat exchanger E1; the second stream of N2 from the air separation cold box passes through valve V1310, enters the electric heater H001 for heating, and enters the molecular sieve MS1302 through valve V1304. The molecular sieve in the first purifier is regenerated by the heated N2, and the regenerated gas is discharged after passing through valve V1308.

[0036] 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 precooling system, characterized in that: include: The heat exchanger is arranged between the air compressor and the molecular sieve system, and is used for heat exchange between the air separation raw material and the gas after leaving the air separation cold box, so as to pre-cool the air separation raw material.

2. The precooling system according to claim 1, characterized in that: Also includes: The first gas-liquid separation tank is connected to the heat exchanger and the molecular sieve system respectively.

3. The precooling system according to claim 1, characterized in that: Also includes: The second gas-liquid separation tank is connected to the heat exchanger and the air separation cold box respectively.

4. The precooling system according to claim 2, characterized in that: Also includes: The second gas-liquid separation tank is connected to the first gas-liquid separation tank, the heat exchanger and the air separation cold box respectively.

5. The precooling system according to claim 1, characterized in that: The molecular sieve system is connected to the air separation cold box.

6. The precooling system according to claim 5, characterized in that: The molecular sieve system comprises two molecular sieves for switching use and an electric heater.

7. The precooling system according to claim 1, characterized in that: The precooling system has a cold box shell on the outside.

8. The precooling system according to claim 7, characterized in that: The heat exchanger and the molecular sieve system are stacked and arranged in the cold box shell.

9. An air separation plant, comprising the precooling system according to any one of claims 1 to 8.

Images