Internal compression air separation poor krypton xenon extraction device and start-stop control system

Abstract

The utility model belongs to the technical field of air separation, and particularly discloses an internal compression air separation poor krypton xenon extraction device and a start-stop control system, which comprise a lower tower, a main cooler, an upper tower, a gas-liquid separator, a liquid oxygen evaporator, a liquid oxygen adsorber, a liquid oxygen pump and a liquid jet evaporator, all the devices are communicated through pipelines, liquid oxygen is buffered through the gas-liquid separator before entering the liquid oxygen pump, the capacity of rapidly switching two working conditions of producing poor krypton xenon and not producing poor krypton xenon is achieved, and due to the fact that the gas-liquid separator does not participate in heat exchange and rectification, potential safety hazards do not exist in the change of the liquid level of the gas-liquid separator. Therefore, the safety of rapid working condition switching equipment can be guaranteed, and stable working condition operation of the main tower is guaranteed.

Description

TECHNICAL FIELD

[0001] The utility model belongs to air separation technical field, especially relate to a kind of inner compression air separation krypton-xenon extraction device and start-stop control system. BACKGROUND

[0002] At present, China mainly extracts krypton and xenon gas from the by-products of air separation equipment. Under normal pressure, the boiling point of krypton is -153.2℃, and the boiling point of xenon is -109.1℃, both of which are higher than the boiling point of oxygen (-182.97℃). Therefore, in the air separation equipment, krypton and xenon mainly exist in liquid oxygen, which is usually discharged with product oxygen or product liquid oxygen.

[0003] Since the inner compression air separation is the direct vaporization of liquid oxygen out of the cold box after being compressed in the cold box, it is relatively difficult to extract krypton and xenon from the inner compression air separation, and the extraction rate is low. Therefore, under normal circumstances, liquid oxygen is extracted from the lowermost two to three theoretical plates of the upper tower as a product before the liquid oxygen enters the main cold, and then sent out of the cold box after being vaporized and reheated by the liquid oxygen pump. The concentration of krypton and xenon here is more than ten times lower than that of the main cold, reducing the amount of krypton and xenon taken away by oxygen products, thereby improving the extraction rate of krypton and xenon. However, there is a problem with this method. When producing krypton and xenon, a large amount of liquid oxygen is extracted from the main cold, and hydrocarbons will not accumulate in the main cold, which is safe. When not producing krypton and xenon, in order to ensure the safety of the main cold, product oxygen must be extracted from the main cold. The extraction of krypton and xenon has great safety risks and many interlocks, and it is easy to cause emergency shutdown. Therefore, it is easy to cause accidents when manually adjusting the position of liquid oxygen extraction. UTILITY MODEL CONTENTS

[0004] In view of the deficiencies of the prior art, the purpose of the utility model is to provide an inner compression air separation krypton-xenon extraction device and start-stop control system, which at least solves one of the problems in the background art.

[0005] The utility model provides the following technical scheme:

[0006] An inner compression air separation krypton-xenon extraction device, comprising a lower tower, a main cold, an upper tower, a gas-liquid separator, a liquid oxygen evaporator, a liquid oxygen adsorber, a liquid oxygen pump, and a liquid jet evaporator. The devices are connected by pipelines, and the connection relationship is as follows:

[0007] The main heat exchange raw material air inlet is connected to the lower tower, and the main heat exchange raw material air inlet is also connected to the liquid oxygen evaporator. The liquid oxygen evaporator is connected to the lower tower by a pipeline.

[0008] The bottom of the upper tower is connected to the top of the liquid oxygen evaporator by a pipeline to provide backflow liquid. The bottom of the upper tower is connected to the gas-liquid separator by a pipeline, and the gas-liquid separator is connected to the liquid oxygen pump by a pipeline. The liquid oxygen pump and the gas-liquid separator are connected by a pipeline, and the backflow liquid in the liquid oxygen pump flows back to the gas-liquid separator.

[0009] The top of the gas-liquid separator is connected to the upper column by a pipeline; the main cold is connected to the liquid oxygen adsorber by a pipeline and then connected to the liquid oxygen evaporator.

[0010] Preferably, the poor krypton-xenon liquid in the liquid oxygen evaporator enters the lower column by a pipeline.

[0011] Preferably, the liquid oxygen of the main cold enters the liquid oxygen pump through a pipeline after passing through the gas-liquid separator and then enters the main regenerative heat exchanger through a pipeline.

[0012] Preferably, the main cold is connected by a pipeline, and part of the liquid nitrogen in the main cold enters the top of the lower column through a pipeline, and part of the liquid nitrogen is discharged and collected through a pipeline.

[0013] Preferably, the liquid oxygen evaporator produces a part of the poor krypton-xenon liquid which enters the product pipeline for product collection, and the other part enters the liquid jet evaporator through a pipeline.

[0014] Preferably, the main cold and the liquid oxygen evaporator are both connected to the non-condensable gas discharge pipeline for discharging non-condensable gas.

[0015] Preferably, the liquid nitrogen in the upper column and the main cold is discharged through a liquid nitrogen pipeline.

[0016] Preferably, the liquid oxygen in the main cold and the gas-liquid separator can be sent into the liquid jet evaporator through a pipeline.

[0017] An on-off control system of an internal compression air separation krypton-xenon extraction device, the on-off control system comprising a plurality of valves connected to respective pipelines of the extraction device, and the on-off control system is controlled by opening the valves.

[0018] The on-off control system specifically comprises a V1 valve arranged on a reflux pipeline between the liquid oxygen evaporator and the upper column, a V2 valve on a flow pipeline from the upper column to the liquid oxygen evaporator, a V3 valve on a flow pipeline from the upper column to the gas-liquid separator, a V4 valve on a flow pipeline from the main cold to the gas-liquid separator, a V5 valve on a flow pipeline from the liquid oxygen evaporator to the lower column, a V61 valve on a feed pipeline of the liquid oxygen pump, a V62 valve on a pipeline between the liquid oxygen pump and the main regenerative heat exchanger, a V63 valve on a pipeline from the liquid oxygen pump back to the gas-liquid separator, a V7 valve on a product liquid oxygen pipeline of the upper column, a V8 valve on a product liquid oxygen pipeline of the main cold, a V9 valve on a feed pipeline of the liquid oxygen adsorber, a V19 valve on a poor krypton-xenon pipeline from the liquid oxygen evaporator, a V21 valve on a non-condensable gas discharge pipeline of the main cold, a V22 valve on a non-condensable gas discharge pipeline of the liquid oxygen evaporator, a V31 valve on a flow pipeline from the lower column to the liquid jet evaporator, a V32 valve on a flow pipeline from the main cold to the liquid jet evaporator, a V33 valve on a flow pipeline from the gas-liquid separator to the liquid jet evaporator, a V34 valve on a flow pipeline from the liquid oxygen evaporator to the liquid jet evaporator, and a V35 valve on a flow pipeline from an outlet pipeline of the air compressor to the liquid jet evaporator.

[0019] Beneficial effects:

[0020] This utility model discloses an internal compression air separation depleted krypton xenon extraction device and a start-stop control system. Before liquid oxygen enters the liquid oxygen pump, it is buffered by a gas-liquid separator, enabling rapid switching between two operating conditions: producing depleted krypton xenon and not producing depleted krypton xenon. Since the gas-liquid separator does not participate in heat exchange and distillation, there is no safety hazard due to changes in its liquid level. Therefore, the safety of the device can be guaranteed by rapidly switching operating conditions, and the stable operation of the main tower can be ensured. Attached Figure Description

[0021] To more clearly illustrate the technical solutions of the embodiments of this utility model, the drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this utility model and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained from these drawings without creative effort.

[0022] Figure 1 This is a schematic diagram of an internal compression air separation depleted krypton xenon extraction device and its start-stop control system according to this utility model. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this utility model, not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this utility model without creative effort are within the scope of protection of this utility model.

[0024] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0025] Example

[0026] refer to Figure 1An internal compression air separation depleted krypton xenon extraction device includes a lower tower 1, a main cooler 3, an upper tower 2, a gas-liquid separator 4, a liquid oxygen evaporator 6, a liquid oxygen adsorber 5, a liquid oxygen pump 7, and a liquid jet evaporator 8. The devices are connected via pipelines as follows: the main heat exchange feed air inlet is connected to the lower tower 1, which is also connected to the liquid oxygen evaporator 6. The liquid oxygen evaporator 6 is connected to the lower tower 1 via a pipeline. The bottom of the upper tower 2 is connected to the top of the liquid oxygen evaporator 6 via a pipeline to provide reflux liquid. The bottom of the upper tower 2 is connected to the gas-liquid separator 4 via a pipeline. The gas-liquid separator 4 is connected to the liquid oxygen pump 7 via a pipeline. The liquid oxygen pump 7 is connected to the gas-liquid separator 4 via a pipeline, and the reflux liquid in the liquid oxygen pump 7 flows back to the gas-liquid separator 4. The top of the gas-liquid separator 4 is connected to the upper tower 2 via a pipeline. The main cooler 3 is connected to the liquid oxygen adsorber 5 and then to the liquid oxygen evaporator 6 via a pipeline.

[0027] Specifically, during the production of the lean krypton xenon tower, the air from the main heat exchanger (pressure: 4.4 bar, temperature: -173.5℃) is partially sent to the lower tower C1 for distillation, and partially sent to the liquid oxygen evaporator C901 to provide a heat source. After being cooled into liquid air by the lean krypton xenon liquid in the liquid oxygen evaporator C901, it is sent to the lower tower C1 via valve V5. The liquid oxygen from the last two trays at the bottom of the upper tower (pressure: 1.35 bar, temperature: -179.8℃) is partially sent to the top of the liquid oxygen evaporator C901 via valve V2 to provide reflux liquid, and partially sent to the gas-liquid separator LT1 via valve V3, and then sent to the liquid oxygen OP601. After being reheated by the main heat exchanger, it is sent out as product oxygen. The reflux liquid from the liquid oxygen pump flows back to the upper part of the gas-liquid separator LT1. The oxygen separated at the top of the gas-liquid separator LT1 returns to the upper C2, and a portion of the liquid oxygen is sent to the liquid storage tank via valve V7 as product liquid oxygen. Liquid oxygen from the main refrigeration unit passes through valve V9 and is sent to the AD901 liquid oxygen adsorber. After adsorbing N2O from the liquid oxygen, it is sent to the middle section of liquid oxygen evaporator C901 to participate in distillation.

[0028] In one possible implementation, the lean krypton-xenon liquid in the liquid oxygen evaporator 6 enters the lower column 1 through a pipeline. Specifically, when lean krypton-xenon production is stopped: part of the air from the main heat exchanger (pressure: 4.4 bar, temperature: -173.5℃) goes to the lower column C1 for distillation, and part goes to the liquid oxygen evaporator C901 to provide a heat source. After being cooled into liquid air by the lean krypton-xenon liquid in the liquid oxygen evaporator C901, it is sent to the lower column C1 via valve V5. The liquid oxygen from the main refrigeration unit (pressure: 1.35 bar, temperature: -179.8℃) enters the gas-liquid separator LT1 through valve V4 and is then sent to the liquid oxygen OP601. After being reheated by the main heat exchanger, it is sent out as product oxygen. The reflux liquid from the liquid oxygen pump flows back to the upper part of the gas-liquid separator LT1. The oxygen separated at the top of the gas-liquid separator LT1 returns to the upper C2, and a portion of the liquid oxygen passes through valve V8 and is sent to the liquid storage tank as product liquid oxygen.

[0029] As one possible implementation, the liquid oxygen from the main cooler 3 enters the liquid oxygen pump 7 through a pipeline via a gas-liquid separator 4, and then enters the main heat exchanger for reheating through another pipeline.

[0030] As one possible implementation, the bottom of the main cooler 3 is connected to a pipe, through which part of the liquid nitrogen in the main cooler 3 enters the top of the lower tower 1, and part of the liquid nitrogen is discharged and collected through the pipe.

[0031] As one possible implementation, part of the lean krypton xenon liquid produced by the liquid oxygen evaporator 6 enters the finished product pipeline for product collection, while the other part enters the liquid jet evaporator 8 through the pipeline.

[0032] As one possible implementation, both the main cooler 3 and the liquid oxygen evaporator 6 are connected to non-condensable gas discharge pipes for discharging non-condensable gases.

[0033] As one possible implementation, the liquid nitrogen in the upper tower 2 and the main cooler 3 is discharged through a liquid nitrogen pipeline.

[0034] As one possible implementation, the liquid oxygen in the main cooler 3 and the gas-liquid separator 4 can be sent into the liquid jet evaporator 8 through a pipeline.

[0035] For ease of understanding, the start-stop control system specifically includes: a V1 valve on the reflux pipe between the liquid oxygen evaporator 6 and the upper tower 2; a V2 valve on the flow pipe from the upper tower 2 to the liquid oxygen evaporator 6; a V3 valve on the flow pipe from the upper tower 2 to the gas-liquid separator 4; a V4 valve on the flow pipe from the main refrigeration unit 3 to the gas-liquid separator 4; a V5 valve on the flow pipe from the liquid oxygen evaporator 6 to the lower tower 1; a V61 valve on the feed pipe of the liquid oxygen pump 7; a V62 valve on the pipe between the liquid oxygen pump 7 and the main heat exchanger / reheater; a V63 valve on the pipe from the liquid oxygen pump 7 back to the gas-liquid separator 4; a V7 valve on the liquid oxygen product pipe of the upper tower 2; and a V5 valve on the liquid oxygen product pipe of the main refrigeration unit 3. V8 valve, V9 valve on the feed pipe of liquid oxygen adsorber 5, V19 valve on the discharge lean krypton xenon pipe of liquid oxygen evaporator 6, V21 valve on the non-condensable gas discharge pipe of main refrigeration unit 3, V22 valve on the non-condensable gas discharge pipe of liquid oxygen evaporator 6, V31 valve on the flow pipe from lower tower 1 to liquid jet evaporator 8, V32 valve on the flow pipe from main refrigeration unit 3 to liquid jet evaporator 8, V33 valve on the flow pipe from gas-liquid separator 4 to liquid jet evaporator 8, V34 valve on the flow pipe from liquid oxygen evaporator 6 to liquid jet evaporator 8, and V35 valve on the flow pipe from air compressor outlet pipe to liquid jet evaporator 8.

[0036] A start-up and shutdown control system for an internal compression air separation unit for extracting lean krypton xenon is disclosed. The system includes multiple valves connected to various pipelines within the extraction unit, controlling start-up and shutdown by controlling the opening and closing of these valves. The control system also includes a lower column, a main cooler, an upper column, a gas-liquid separator, a liquid oxygen evaporator, a liquid oxygen adsorber, a liquid oxygen pump, a liquid jet evaporator, a set of regulating valves and manual valves, and level, pressure, resistance, and purity instruments, all integrated into the overall DCS (Distributed Control System) of the air separation unit. In operating condition one, when the lean krypton xenon column is producing, valves V2, V3, V9, V5, and V7 are open, while V4 and V8 are closed. In operating condition two, when lean krypton xenon production is stopped, valves V4 and V8 are open, while V2, V3, V9, V5, and V7 are closed. It should be understood that the valve openings are preset during operating condition switching to minimize level fluctuations in the liquid oxygen buffer LT1.

[0037] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. For those skilled in the art, the present utility model can have various modifications and variations. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. An internal compression air separation depleted krypton xenon extraction device, characterized in that, It includes a lower tower (1), a main cooler (3), an upper tower (2), a gas-liquid separator (4), a liquid oxygen evaporator (6), a liquid oxygen adsorber (5), a liquid oxygen pump (7), and a liquid jet evaporator (8); the equipment is connected by pipelines, and the connection relationship is as follows: The main heat exchange raw material air inlet is connected to the lower tower (1), and the main heat exchange raw material air inlet is also connected to the liquid oxygen evaporator (6). The liquid oxygen evaporator (6) is connected to the lower tower (1) through a pipeline. The bottom of the upper tower (2) is connected to the top of the liquid oxygen evaporator (6) through a pipe to provide reflux liquid. The bottom of the upper tower (2) is connected to the gas-liquid separator (4) through a pipe. The gas-liquid separator (4) is connected to the liquid oxygen pump (7) through a pipe. The liquid oxygen pump (7) is connected to the gas-liquid separator (4) through a pipe. The reflux liquid in the liquid oxygen pump (7) flows back to the gas-liquid separator (4). The top of the gas-liquid separator (4) is connected to the upper tower (2) via a pipe; the main cooler (3) is connected to the liquid oxygen adsorber (5) via a pipe and then to the liquid oxygen evaporator (6).

2. The internal compression air separation depleted krypton xenon extraction device according to claim 1, characterized in that, The lean krypton xenon liquid in the liquid oxygen evaporator (6) enters the lower tower (1) through a pipeline.

3. The internal compression air separation depleted krypton xenon extraction device according to claim 1, characterized in that, Liquid oxygen from the main cooler (3) enters the liquid oxygen pump (7) through a gas-liquid separator (4) via a pipeline, and then enters the main heat exchanger for reheating via another pipeline.

4. The internal compression air separation depleted krypton xenon extraction device according to claim 1, characterized in that, The bottom of the main cooler (3) is connected to a pipe. Some of the liquid nitrogen in the main cooler (3) enters the top of the lower tower (1) through the pipe, and some of the liquid nitrogen is discharged and collected through the pipe.

5. The internal compression air separation depleted krypton xenon extraction device according to claim 1, characterized in that, The lean krypton xenon liquid produced by the liquid oxygen evaporator (6) is partially collected in the finished product pipeline, and the other part is collected in the liquid jet evaporator (8) through the pipeline.

6. The internal compression air separation depleted krypton xenon extraction device according to claim 1, characterized in that, Both the main cooler (3) and the liquid oxygen evaporator (6) are connected to non-condensable gas discharge pipes for discharging non-condensable gas.

7. The internal compression air separation depleted krypton xenon extraction device according to claim 1, characterized in that, Liquid nitrogen in the upper tower (2) and the main cooler (3) is discharged through liquid nitrogen pipelines.

8. The internal compression air separation depleted krypton xenon extraction device according to claim 1, characterized in that, Liquid oxygen in the main cooler (3) and gas-liquid separator (4) can be sent into the liquid jet evaporator (8) through a pipeline.

9. A start-stop control system for an internal compression air separation depleted krypton xenon extraction device, used to control the internal compression air separation depleted krypton xenon extraction device as described in any one of claims 1-8, characterized in that, The start-stop control system includes multiple valves connected to various pipelines of the extraction device, and the system starts and stops by controlling the opening and closing of the valves.

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