Oxygen supply system using space division device to recover liquid oxygen cold energy

Abstract

The utility model discloses an oxygen supply system recycling liquid oxygen cold quantity by air separation device, oxygen supply system maintains user oxygen supply load and increases the liquid oxygen in liquid oxygen storage tank and air separation device communication realizes liquid oxygen cold quantity utilization to air separation rectification tower, simultaneously uses air separation output liquid oxygen pipeline for feed pipe condensation, realizes the effect of energy -conserving and consumption -reducing, promotes economic benefits.

Description

Technical Field

[0001] This utility model relates to the field of air separation oxygen production technology, specifically an oxygen supply system that utilizes an air separation unit to recover the cooling capacity of liquid oxygen. Background Technology

[0002] A certain project currently supplies oxygen to downstream customers through an air separation unit. Due to the influence of downstream production process load, the oxygen consumption fluctuates greatly. In order to ensure the oxygen supply, liquid oxygen storage tanks, vaporizers and other devices are installed on site. When the oxygen consumption increases, the liquid oxygen in the storage tank is vaporized into oxygen through the vaporizer and then fed into the gas supply pipeline to meet the customer's gas demand.

[0003] Liquid oxygen is vaporized and supplied as gas. The cooling energy generated by vaporization is directly dissipated, while the air separation unit itself requires cooling energy. The cooling energy from vaporization cannot be recovered and reused, resulting in energy loss.

[0004] If the cooling energy from the vaporization of liquid oxygen in the storage tank is used in an air separation unit, it is expected to reduce costs and increase efficiency. Utility Model Content

[0005] The purpose of this invention is to provide an oxygen supply system that utilizes an air separation unit to recover the cold energy of liquid oxygen, thereby rationally recovering the cold energy generated by direct oxygen supply from current liquid oxygen storage tanks and achieving cost reduction and efficiency improvement.

[0006] To achieve the above objectives, the solution of this utility model is as follows: An oxygen supply system that utilizes an air separation unit to recover the cooling capacity of liquid oxygen includes a liquid oxygen storage tank and an air separation unit; the air separation unit includes a purifier, a condenser, and an air separation distillation column connected in sequence; wherein: The purifier is provided with a feed pipe that connects to the lower part of the air separation distillation column via a condenser and a throttle valve. The throttle valve is used to condense air into a liquid state. The purifier is provided with a second feed pipe that connects to the lower part of the air separation distillation column via a condenser; the second feed pipe is located inside the condenser and has a branched feed pipe third that connects to the upper part of the air separation distillation column via an expander. The upper part of the air separation distillation column is equipped with a liquid oxygen pipe for outputting condensed and separated liquid oxygen; the liquid oxygen pipe is connected to the oxygen supply pipe after passing through the condenser. The lower part of the liquid oxygen storage tank is connected to the upper part of the air separation distillation column via pipelines.

[0007] Furthermore, the lower part of the liquid oxygen storage tank is connected to a vaporizer via a pipeline, and the output end of the vaporizer is connected to an oxygen delivery pipe.

[0008] Furthermore, the feed pipe is equipped with a booster at the output end of the purifier.

[0009] Furthermore, a pump is installed on the liquid oxygen pipe.

[0010] Furthermore, the lower part of the liquid oxygen storage tank is connected to the upper part of the air separation distillation column via pump two.

[0011] Furthermore, the oxygen supply system also includes a connected air compressor and a cooling tower, with the output end of the cooling tower connected to the feed end of the purifier.

[0012] Compared with the prior art, the beneficial effects of this utility model are as follows: The oxygen supply system described in this utility model connects the liquid oxygen in the liquid oxygen storage tank, which is increased to maintain the user's oxygen supply load, with the air separation unit to realize the utilization of the liquid oxygen cooling capacity to the air separation distillation tower. At the same time, the liquid oxygen output pipeline of the air separation is used for condensation in the feed pipe, thereby achieving the effect of energy saving and consumption reduction and improving economic efficiency. Attached Figure Description

[0013] Figure 1 This utility model provides an overall schematic diagram of an oxygen supply system that utilizes an air separation unit to recover the cooling capacity of liquid oxygen.

[0014] The attached figures are labeled as follows: AC1, booster compressor; AC2, air compressor; CT1, cooling tower; E1, condenser; EX1, expander; L1, purified gas pipe; L11, feed pipe one; L12, feed pipe two; L121, feed pipe three; L2, liquid oxygen pipe; L3, oxygen delivery pipe; P1, pump one; P2, pump two; PU1, purifier; ST1, liquid oxygen storage tank; T1, air separation distillation column; TV1, throttle valve; V1, vaporizer. Detailed Implementation

[0015] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0016] It should be understood that the terms "upper", "lower", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0017] It should also be noted that, unless otherwise explicitly specified and limited, terms such as "installation," "connection," "joining," "fixing," and "setting" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication between two components or the interaction between two components. For those skilled in the art, the specific meaning of the above terms in this utility model can be understood according to the specific circumstances.

[0018] In one embodiment, such as Figure 1 As shown, an oxygen supply system for recovering the cooling capacity of liquid oxygen using an air separation unit is proposed, comprising a liquid oxygen storage tank ST1 and an air separation unit; the air separation unit includes a purifier PU1, a condenser E1, and an air separation distillation column T1 connected in sequence; wherein: The purifier PU1 is provided with a feed pipe L11 that connects to the lower part of the air separation distillation column T1 via a condenser E1 and a throttle valve TV1. The throttle valve TV1 is used to condense air into a liquid state. The purifier PU1 is provided with a second feed pipe L12 that is connected to the lower part of the air separation distillation column T1 via the condenser E1; the second feed pipe L12 is located inside the condenser or the third feed pipe L121 with a branch at the output end is connected to the upper part of the air separation distillation column T1 via the expander EX1. The upper part of the air separation distillation column T1 is equipped with a liquid oxygen pipe L2 for outputting condensed and separated liquid oxygen; the liquid oxygen pipe L2 is connected to the oxygen supply pipe L3 after passing through the condenser E1. The lower part of the liquid oxygen storage tank ST1 is connected to the upper part of the air separation distillation column T1 via a pipeline.

[0019] The air separation distillation column T1 is a common air separation distillation column for separating liquid oxygen and liquid ammonia. Specifically, after the air is cryogenically cooled, it enters the air separation distillation column T1. The oxygen with a higher boiling point enters the upper part (upper column) and is then condensed to obtain liquid oxygen, while the lower part (lower column) is enriched with nitrogen and condensed to obtain liquid nitrogen.

[0020] In the above embodiment, the oxygen storage tank ST1, which is required by the original project to ensure a stable oxygen supply to users, is directly connected to the upper part of the air separation distillation column T1, so as to bring the cooling capacity of liquid oxygen into the distillation column and realize the recycling of cooling capacity. In addition, the liquid oxygen collected from the upper part enters the condenser E1 through the liquid oxygen pipe L2 to provide cooling capacity and then vaporizes and enters the oxygen supply pipe L3 to supply oxygen to users. At the same time, in the output pipeline of the purifier PU1, the feed pipe one L11 enters the condenser E1 and is condensed to a certain temperature. After being liquefied through the throttling valve TV1, it enters the lower part of the air separation distillation column T1 as reflux liquid; the feed pipe two L12 enters the condenser E1 and is condensed to a certain temperature before entering the lower part of the air separation distillation column T1 as rising steam; the feed pipe three L121 is briefly condensed by the condenser E1 and then enters the expander EX1 and is connected to the upper part of the air separation distillation column T1 as rising steam. It transfers mass and heat with the reflux liquid and finally separates to obtain liquid oxygen at the bottom of the upper column.

[0021] In the above embodiment, within the condenser E1, the feed pipes L11 and L12 exchange heat with the liquid oxygen pipe L2 in a counter-current manner to improve the condensation effect. After heat exchange, the liquid oxygen in the liquid oxygen pipe L2 becomes gaseous and then enters the oxygen supply pipe L3 to supply oxygen to the user. It is understood that because the liquid oxygen in the liquid oxygen pipe L2 is slightly below its boiling point, and to ensure oxygen supply balance, the amount of air passing through the feed pipes L11 and L12 is relatively large. Therefore, the temperature of the condensed air in the feed pipes L11 and L12 is usually 10-20°C higher than the liquid oxygen temperature, such as -173°C, and it remains a gas. Therefore, a throttling valve TV1 added to the feed pipe L11 throttles and expands the liquid, liquefying it into a liquid for use as reflux liquid in the lower tower. Feed pipe 2 L12 can be used as the rising steam in the lower column; feed pipe 3 L121, after brief condensation and expansion by expander EX1, is controlled to reduce the pressure to 40 kPa and the temperature to -156℃ before being used as rising steam in the upper column. By rationally utilizing the cooling capacity of liquid oxygen output from oxygen storage tank ST1 for the air separation system, energy saving and consumption reduction are achieved, thereby realizing cost reduction and efficiency improvement.

[0022] In a preferred embodiment, in order to ensure the oxygen supply to users, the original oxygen supply system can be used to continue supplying oxygen when the air separation system needs maintenance. That is, a pipeline is installed at the lower part of the liquid oxygen storage tank ST1 to connect to the vaporizer V1, and the oxygen supply pipe L3 is connected through the output end of the vaporizer V1 to supply oxygen to users.

[0023] In a preferred embodiment, the feed pipe L11 is equipped with a booster compressor C1 at the output end of the purifier PU1. During the heat exchange with air, the cooling capacity of the liquid oxygen output from the oxygen storage tank ST1 is retained in the air separation system. At this time, the amount of gas entering the expander can be reduced to reduce refrigeration, while the amount of gas entering the booster compressor can be increased. The pressure in the distillation column rises accordingly, and the liquid production in the column increases accordingly. This can reduce system energy consumption and increase liquid nitrogen production.

[0024] In a preferred embodiment, in order to ensure the stability of the flow rate increase, a booster or delivery pump is provided on the pipeline. For example, pump P1 is provided on the liquid oxygen pipeline L2, and the lower part of the liquid oxygen storage tank ST1 is connected to the upper part of the air separation distillation column T1 via pump P2.

[0025] In a preferred embodiment, as a complete air separation system, the oxygen supply device further includes an air compressor AC2 and a cooling tower CT1. The output end of the cooling tower CT1 is connected to the feed end of the purifier PU1. Air is drawn in from the atmosphere by the air compressor AC2, compressed to a suitable pressure such as 0.5 MPa, and then cooled to a suitable temperature, such as 10°C, by the cooling tower CT1. The air is then purified by the purifier PU1 to remove carbon dioxide, hydrocarbons, and residual water vapor. The purifier PU1 is filled with alumina and 13X molecular sieves; those skilled in the art can also choose other commonly used adsorbents for filling.

[0026] It is understandable that the materials of the components used in the above oxygen supply system can be selected according to the requirements of low temperature corrosion resistance, and commonly used instruments, meters or valves can also be selected or added according to the operational requirements. All of the above are within the design scope of this solution and will not be elaborated here.

[0027] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. An oxygen supply system that utilizes an air separation unit to recover the cooling capacity of liquid oxygen, characterized in that, It includes a liquid oxygen storage tank (ST1) and an air separation unit; the air separation unit includes a purifier (PU1), a condenser (E1), and an air separation distillation column (T1) connected in sequence; wherein: The purifier (PU1) is provided with a feed pipe (L11) that connects to the lower part of the air separation distillation column (T1) via a condenser (E1) and a throttle valve (TV1). The throttle valve (TV1) is used to condense air into a liquid state. The purifier (PU1) is provided with a second feed pipe (L12) that is connected to the lower part of the air separation distillation column (T1) via a condenser (E1); the second feed pipe (L12) is located in the condenser and has a branch feed pipe (L121) that is connected to the upper part of the air separation distillation column (T1) via an expander (EX1). The upper part of the air separation distillation column (T1) is equipped with a liquid oxygen pipe (L2) for outputting condensed and separated liquid oxygen; the liquid oxygen pipe (L2) is connected to the oxygen supply pipe (L3) after passing through the condenser (E1). The lower part of the liquid oxygen storage tank (ST1) is connected to the upper part of the air separation distillation column (T1) via pipelines.

2. The oxygen supply system according to claim 1, characterized in that, The lower part of the liquid oxygen storage tank (ST1) is connected to a vaporizer (V1), and the output end of the vaporizer (V1) is connected to an oxygen delivery pipe (L3).

3. The oxygen supply system according to claim 1, characterized in that, The feed pipe (L11) is equipped with a booster (C1) at the output end of the purifier (PU1).

4. The oxygen supply system according to claim 1, characterized in that, Pump 1 (P1) is installed on the liquid oxygen pipe (L2).

5. The oxygen supply system according to claim 1, characterized in that, The lower part of the liquid oxygen storage tank (ST1) is connected to the upper part of the air separation distillation column (T1) via pump two (P2).

6. The oxygen supply system according to claim 1, characterized in that, The oxygen supply system also includes an air compressor (AC2) and a cooling tower (CT1) connected together, with the output end of the cooling tower (CT1) connected to the feed end of the purifier (PU1).

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