Compressed-air purification system

Abstract

The present application relates to the technical field of compressed-air purification. Disclosed is a compressed-air purification system. The compressed-air purification system of the present application comprises a spray device and a rotary spray absorption device, wherein the spray device comprises a sprayer and a first working-medium tank; the rotary spray absorption device comprises a rotary spray absorber and a second working-medium tank; a liquid inlet of the sprayer is in communication with a first liquid outlet of the first working-medium tank by means of a pipeline; a second liquid outlet of the first working-medium tank is in communication with a liquid inlet of the second working-medium tank; and a liquid outlet of the second working-medium tank is in communication with a liquid inlet of the rotary spray absorber. The compressed-air purification system of the present application overcomes the limitations in the prior art regarding compressed-air purification systems in terms of applicable working conditions and solves the technical problem of low controllability in the purification process. The compressed-air purification system can be widely applied in the compressed-air energy storage industry in fields such as petroleum, chemicals, metallurgy, electric power, machinery, light industry, textiles, automobile manufacturing, electronics, food products, medicine, biochemistry, national defense, and electric power energy storage.

Description

CROSS-REFERENCE TO RELATED APPLICATION

[0001] The present application claims priority from the Chinese patent application filed with the China National Intellectual Property Administration on March 20, 2024, with application number 202410319886.X and entitled “COMPRESSED-AIR PURIFICATION SYSTEM”, the entire content of which is incorporated herein by reference. TECHNICAL FIELD

[0002] The present application relates to the technical field of compressed-air purification, and in particular to a compressed-air purification system. BACKGROUND ART

[0003] Compressed air is air compressed by an external force. Air is compressible. Air whose volume is reduced and pressure is increased after mechanical work is performed by an air compressor is called compressed air. Compressed air is an important power source. Compared with other energy sources, it has the following obvious characteristics: clear and transparent, convenient to transport, no special harmful properties, no fire risk, not afraid of overload, capable of working in many adverse environments, and air is available everywhere on the ground and inexhaustible. Compressed air is a process gas source with multiple uses, and its application range covers petroleum, chemical engineering, metallurgy, electric power, machinery, light industry, textile, automobile manufacturing, electronics, food, medicine, biochemistry, national defense, scientific research and other industries and departments. In most cases, compressed air needs to be purified before being supplied to users.

[0004] In the process of implementing the present application, the inventors found that the prior art has at least the following problems:

[0005] The manufacturing methods and storage methods of compressed air are not exactly the same, and therefore the impurities contained in the compressed air also differ. For example, a reciprocating compressor used in manufacturing compressed air contains oil, and the compressed air produced thereby contains oily substances, which can further be subdivided into large oil droplets, small oil droplets, emulsified oil droplets, etc. Acid radical ions, acidic or alkaline gases may be introduced into a compressed air storage device for storing compressed air, and this phenomenon is particularly obvious in the case of underground gas storage. In addition, one of the by-products of compressed air is free water, and the above-mentioned acidic or alkaline gases are extremely soluble in free water and exist in the form of ions. The compressed air storage device may also contain solid particulate impurities such as dust, such as mud, sand, rust, rock salt particles, etc. The compressed air containing the above impurities will cause serious safety hazards in subsequent use, mainly in two aspects. On the one hand, if the compressed air is introduced into a process unit, the impurities may affect the normal operation of the main process unit. On the other hand, devices that use compressed air at the user end are usually made of steel, and ordinary steel is extremely prone to electrochemical corrosion under impurity-containing wet air conditions. Since the use scenarios of compressed air are usually medium-pressure working conditions and high-pressure working conditions, corrosion may cause very serious consequences such as steel plate fracture and gas leakage. However, the compressed-air purification systems in the prior art have technical problems such as few types of impurities that can be purified, limited applicable working conditions, and low controllability of the purification process.

[0006] Based on this, how to provide a compressed-air purification system that can simultaneously remove oil, solid dust, free water and chemical impurities dissolved therein carried by compressed air, adapt to various types of impurities, and provide clean dry compressed gas after purification, facilitating subsequent applications in various occasions, is a technical problem urgently to be solved by those skilled in the art. SUMMARY OF THE INVENTION

[0007] The purpose of the present application is to provide a compressed-air purification system capable of simultaneously removing oil, solid dust, free water, and chemical impurities dissolved in the free water carried by compressed air.

[0008] To achieve this purpose, in one aspect, there is provided a compressed-air purification system, it comprises a spraying device and a rotary spray absorption device, the spraying device comprises a sprayer and a first working-medium tank, and the rotary spray absorption device comprises a rotary spray absorber and a second working-medium tank; a liquid inlet of the sprayer is in communication with a first liquid outlet of the first working-medium tank through a pipeline, a second liquid outlet of the first working-medium tank is in communication with a liquid inlet of the second working-medium tank, and a liquid outlet of the second working-medium tank is in communication with a liquid inlet of the rotary spray absorber through a pipeline; the second liquid outlet of the first working-medium tank is further in communication with the liquid inlet of the rotary spray absorber through a pipeline of a first bypass branch; a first valve is provided on the pipeline between the second outlet of the first working-medium tank and the liquid inlet of the second working-medium tank; a second valve is provided on the first bypass branch; compressed air to be purified enters a gas inlet of the sprayer, flows out from a gas outlet of the sprayer, and then enters a gas inlet of the rotary spray absorber.

[0009] Optionally, a first separator is further provided between the sprayer and the rotary spray absorber; compressed air flowing out from the gas outlet of the sprayer enters a gas inlet of the first separator, and after flowing out from a gas outlet of the first separator, enters the gas inlet of the rotary spray absorber; the first separator is configured to dry the compressed air.

[0010] Optionally, an oil separator is further provided between the first separator and the rotary spray absorber; the gas outlet of the first separator is in communication with a gas inlet of the oil separator through a first branch, and a gas outlet of the oil separator is in communication with the gas inlet of the rotary spray absorber; a third valve is provided on the first branch; a fifth valve is provided at the gas outlet of the oil separator.

[0011] Optionally, the gas outlet of the first separator further comprises a second branch, one end of the second branch is in communication with the gas outlet of the first separator, and the other end of the second branch is in communication with an outlet pipeline of the fifth valve, and compressed air flowing out from the second branch enters the gas inlet of the rotary spray absorber; a fourth valve is provided on the second branch.

[0012] Optionally, a slug catcher is further provided before an inlet of the sprayer; compressed air to be purified enters a gas inlet of the slug catcher, and after flowing out from a gas outlet of the slug catcher, enters the gas inlet of the sprayer.

[0013] Optionally, a second separator is further provided at an outlet side of the rotary spray absorber, compressed air flowing out from a gas outlet of the rotary spray absorber enters a gas inlet of the second separator, and flows out from a gas outlet of the second separator.

[0014] Optionally, the first working-medium tank contains water, alkali or acid, and the second working-medium tank contains alkali or acid.

[0015] Optionally, a sixth valve is provided at an outlet of the second working-medium tank; the first working-medium tank contains water, the second working-medium tank contains alkali, the first valve and the sixth valve are opened, and the second valve is closed, for purifying compressed air.

[0016] Optionally, a sixth valve is provided at the outlet of the second working-medium tank; the first working-medium tank contains water, the second working-medium tank contains acid, the first valve and the sixth valve are opened, and the second valve is closed, for purifying compressed air.

[0017] Optionally, a sixth valve is provided at the outlet of the second working-medium tank; the first working-medium tank contains water, the first valve and the sixth valve are closed, and the second valve is opened, for purifying compressed air.

[0018] Optionally, the first separator is a cyclone separator or a vane separator; and / or the second separator is a cyclone separator or a vane separator.

[0019] Optionally, a first cooler is provided between the first liquid outlet of the first workingmedium tank and the liquid inlet of the sprayer; and / or a second cooler is provided on the pipeline at the liquid inlet of the rotary spray absorber.

[0020] Optionally, a first high-pressure pump is further provided on the pipeline between the first liquid outlet of the first working-medium tank and the liquid inlet of the sprayer; and / or a second high-pressure pump is provided at the liquid inlet of the rotary spray absorber, an outlet of the second high-pressure pump is in communication with the liquid inlet of the rotary spray absorber, a sixth valve is provided at a liquid outlet pipeline of the second working-medium tank, an inlet of the sixth valve is in communication with the liquid outlet of the second working-medium tank, an outlet of the sixth valve is in communication with an outlet of the second valve, and both the outlet of the sixth valve and the outlet of the second valve are in communication with an inlet of the second high-pressure pump; and / or a low-pressure pump is further provided on the pipeline between the second liquid outlet of the first working-medium tank and the liquid inlet of the second working-medium tank.

[0021] Optionally, a pH detection device is provided at a drain outlet of the rotary spray absorber; the first valve and the sixth valve are controlled to open and the second valve is controlled to close by the pH detection device; or the second valve is controlled to open and the first valve and the sixth valve are controlled to close by the pH detection device; and / or outlet pressures of the low-pressure pump and the second high-pressure pump are controlled by the pH detection device.

[0022] Optionally, the oil separator is an oil-removing coalescer.

[0023] Optionally, a first three-phase separator is further provided before the inlet of the sprayer; compressed air to be purified enters a gas inlet of the first three-phase separator, and after flowing out from a gas outlet of the first three-phase separator, enters the gas inlet of the sprayer.

[0024] Optionally, the first three-phase separator comprises a weir plate, a liquid collection zone, and an ice collection zone; a bottom of the weir plate is connected to an inner bottom wall of the first three-phase separator, and there is a gas-phase space between a top of the weir plate and an inner top wall of the first three-phase separator; a windward side of the weir plate is a side facing the gas inlet of the first three-phase separator, and a leeward side of the weir plate is a back side of the windward side of the weir plate; the liquid collection zone is located in a space below the windward side of the weir plate; the ice collection zone is located in a space below the leeward side of the weir plate; the ice collection zone is provided with a heat tracing heater, and the heat tracing heater is configured to heat the ice collection zone; a first drain outlet of the first three-phase separator is located at a bottom of the liquid collection zone, and a second drain outlet of the first three-phase separator is located at a bottom of the ice collection zone.

[0025] Optionally, a second three-phase separator is further provided before the inlet of the sprayer, and the second three-phase separator is connected in parallel with the first three-phase separator; compressed air to be purified enters the gas inlet of the first three-phase separator, and after flowing out from the gas outlet of the first three-phase separator, enters the gas inlet of the sprayer; or compressed air to be purified enters a gas inlet of the second three-phase separator, and after flowing out from a gas outlet of the second three-phase separator, enters the gas inlet of the sprayer.

[0026] One of the above technical solutions has the following advantages or beneficial effects:

[0027] The compressed-air purification system comprises a spraying device and a rotary spray absorption device, wherein the spraying device comprises a sprayer and a first working-medium tank, the first working-medium tank is configured to store working medium liquid required by the sprayer, and the rotary spray absorption device comprises a rotary spray absorber and a second working-medium tank, the second working-medium tank is configured to store working medium liquid required by the rotary spray absorber. The liquid inlet of the sprayer is in communication with the first liquid outlet of the first working-medium tank through a pipeline, the second liquid outlet of the first working-medium tank is in communication with the liquid inlet of the second working-medium tank, and the liquid outlet of the second working-medium tank is in communication with the liquid inlet of the rotary spray absorber. The first working-medium tank, on the one hand, is in communication with the liquid inlet of the sprayer to provide the sprayer with working medium liquid required for spraying, and on the other hand, is in communication with the liquid inlet of the second working-medium tank to adjust the component concentration of the working medium liquid in the second working-medium tank. The liquid outlet of the second working-medium tank is in communication with the liquid inlet of the rotary spray absorber to provide the rotary spray absorber with required working medium liquid. Therefore, the working medium liquid in the first working-medium tank can further adjust the component concentration of the working medium liquid required by the rotary spray absorber. A first valve is provided on the pipeline between the second liquid outlet of the first working-medium tank and the liquid inlet of the second working-medium tank. By adjusting the opening degree of the first valve, the amount of working medium liquid entering the second working-medium tank from the first workingmedium tank is adjusted, thereby the component concentration of the working medium liquid in the second working-medium tank is adjusted, and further the component concentration of the working medium liquid is adjusted to enter the rotary spray absorber.

[0028] The second liquid outlet of the first working-medium tank is further in communication with the liquid inlet of the rotary spray absorber through a first bypass branch. The rotary spray absorber can directly use the working medium liquid in the first working-medium tank through the first bypass branch. A second valve is provided on the first bypass branch. By adjusting the opening degree of the second valve, the amount of working medium liquid entering the rotary spray absorber from the first working-medium tank can be adjusted.

[0029] Compressed air to be purified first enters the sprayer, and under the action of the working medium liquid in the first working-medium tank, the compressed air is sprayed, so as to remove large oil droplets and dust, and reduce the concentration of total dissolved solids in free water carried by the compressed air. The compressed air flowing out from the gas outlet of the sprayer enters the rotary spray absorber tangentially from the side. A swirling flow field can be formed inside the rotary spray absorber. After the compressed air to be purified enters from the gas inlet, it is subjected to centrifugal force. At the same time, the working medium liquid is sprayed in radially from the side, and is impacted and cut by the compressed air to be purified and atomized, thereby countless working medium liquid droplets for absorption are formed. The working medium liquid droplets undergo an absorption reaction with chemical impurities-containing free water in the compressed air to be purified. Since a swirling flow field can be formed inside the rotary spray absorber, the purified compressed air is dry compressed air and is discharged from the gas outlet of the rotary spray absorber. The gas outlet of the rotary spray absorber is located at the center of the top of the rotary spray absorber, and the reacted absorption liquid droplets are discharged from the drain outlet at the bottom of the rotary spray absorber.

[0030] Whether to open the first valve or the second valve is determined according to the chemical impurity components dissolved in the free water in the compressed air to be purified. If the working medium liquid in the first working-medium tank can be used to absorb impurities in the compressed air entering the rotary spray absorber, the second valve is opened and the first valve is closed. If the working medium liquid obtained by mixing the working medium liquid in the first working-medium tank and the working medium liquid in the second working-medium tank is required to absorb impurities in the compressed air entering the rotary spray absorber, the first valve is opened and the second valve is closed.

[0031] Based on this, the compressed-air purification system can simultaneously remove oil, solid dust, free water and chemical impurities dissolved therein carried by compressed air, and can also adapt the required impurity-removing working medium liquid according to the components of the above chemical impurities, having the advantages of wide purification range and high controllability. The compressed air purified by the compressed-air purification system is high-quality, clean and dry compressed gas, facilitating subsequent applications in various occasions. It can be widely used in the compressed-air energy storage industry among the fields of petroleum, chemical engineering, metallurgy, electric power, machinery, light industry, textile, automobile manufacturing, electronics, food, medicine, biochemistry, national defense, and electric power energy storage. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] FIG. 1 is a schematic flow diagram of Embodiment 1 of the present application;

[0033] FIG. 2 is a schematic flow diagram of Embodiment 2 of the present application; and

[0034] FIG. 3 is a schematic structural diagram of the first three-phase separator and the second three-phase separator of Embodiment 2 of the present application.

[0035] In the figures: 10-sprayer; 11-first working-medium tank; 12-second valve; 13-first valve; 14-first high-pressure pump; 15-second high-pressure pump; 16-low-pressure pump; 17-first cooler; 20-rotary spray absorber; 21-second working-medium tank; 22-pH detection device; 23-sixth valve; 24-second cooler; 30-first separator; 31-third valve; 32-fourth valve; 33-fifth valve; 40-second separator; 50-slug catcher or gravity separator; 60-oil separator; 70-main drain discharge pipe; 80-first three-phase separator; 81-second three-phase separator; 82-gas outlet valve of the first three-phase separator; 84-gas inlet valve of the first three-phase separator; 85-first drain discharge valve of the first three-phase separator; 86-second drain discharge valve of the first three-phase separator; 87-gas inlet valve of the second three-phase separator; 88-gas inlet of the first three-phase separator; 89-gas outlet of the first three-phase separator; 90-weir plate; 91-heat tracing heater; 92-second drain outlet of the first three-phase separator; 93-first drain outlet of the first three-phase separator; 94-gas outlet valve of the second three-phase separator; 95-first drain discharge valve of the second three-phase separator; 96-second drain discharge valve of the second three-phase separator; 97-liquid collection zone; 98-ice collection zone. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0036] In order to make the technical problems solved by the present application, the technical solutions adopted, and the technical effects achieved clearer, the technical solutions of the embodiments of the present application will be further described in detail below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work shall fall within the protection scope of the present application.

[0037] In the description of the present application, unless otherwise clearly specified and limited, the terms “connected”, “coupled”, and “fixed” should be understood in a broad sense. For example, they may be fixed connections, detachable connections, or integral; they may be mechanical connections or electrical connections; they may be direct connections or indirect connections through an intermediate medium; they may be internal communication between two elements or an interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to specific circumstances.

[0038] In the present application, unless otherwise clearly specified and limited, that a first feature is “on” or “under” a second feature may include direct contact between the first feature and the second feature, or may include non-direct contact between the first feature and the second feature but contact through another feature therebetween. Moreover, that a first feature is “above”, “over” or “on” a second feature includes that the first feature is directly above and obliquely above the second feature, or merely indicates that the horizontal height of the first feature is greater than that of the second feature. That a first feature is “below”, “under” or “beneath” a second feature includes that the first feature is directly below and obliquely below the second feature, or merely indicates that the horizontal height of the first feature is less than that of the second feature.

[0039] Embodiment 1

[0040] To simplify description, in this embodiment, compressed air to be purified is referred to as raw material gas, and purified compressed air is referred to as product gas. As shown in FIG. 1, the compressed-air purification system of this embodiment comprises a spraying device and a rotary spray absorption device, wherein the spraying device comprises a sprayer 10 and a first working-medium tank 11, the first working-medium tank 11 is configured to store working medium liquid required by the sprayer 10, and the rotary spray absorption device comprises a rotary spray absorber 20 and a second working-medium tank 21, the second working-medium tank 21 is configured to store working medium liquid required by the rotary spray absorber 20. The liquid inlet of the sprayer 10 is in communication with the first liquid outlet of the first workingmedium tank 11 through a pipeline, the second liquid outlet of the first working-medium tank 11 is in communication with the liquid inlet of the second working-medium tank 21, and the liquid outlet of the second working-medium tank 21 is in communication with the liquid inlet of the rotary spray absorber 20.

[0041] The first working-medium tank 11, on the one hand, is in communication with the liquid inlet of the sprayer 10 to provide the sprayer 10 with working medium liquid required for spraying, and on the other hand, is in communication with the liquid inlet of the second working-medium tank 21 to adjust the acid / alkali concentration of the working medium liquid in the second workingmedium tank 21. The liquid outlet of the second working-medium tank 21 is in communication with the liquid inlet of the rotary spray absorber 20 to provide the rotary spray absorber 20 with required working medium liquid. Therefore, the working medium liquid in the first workingmedium tank 11 can further adjust the acid / alkali concentration of the working medium liquid required by the rotary spray absorber 20. A first high-pressure pump is provided on the pipeline between the first liquid outlet of the first working-medium tank and the liquid inlet of the sprayer. By adjusting the outlet head of the first high-pressure pump, the amount of working medium liquid entering the sprayer from the first working-medium tank is adjusted. A first valve 13 and a low-pressure pump 16 are provided on the pipeline between the second liquid outlet of the first working-medium tank 11 and the liquid inlet of the second working-medium tank 21. By opening the first valve 13 and adjusting the outlet head of the low-pressure pump 16, the amount of working medium liquid entering the second working-medium tank 21 from the first working-medium tank 11 is adjusted, thereby the acid / alkali concentration of the working medium liquid in the second working-medium tank 21 is adjusted, and further the acid / alkali concentration of the working medium liquid is adjusted to enter the rotary spray absorber 20.

[0042] The second liquid outlet of the first working-medium tank 11 is further in communication with the liquid inlet of the rotary spray absorber 20 through a first bypass branch. The rotary spray absorber 20 can directly use the working medium liquid in the first working-medium tank 11 through the first bypass branch. A second valve 12 is provided on the first bypass branch. By opening the second valve 12, closing the first valve 13 and the sixth valve 23, and adjusting the outlet head of the second high-pressure pump, the amount of working medium liquid entering the rotary spray absorber 20 from the first working-medium tank 11 can be adjusted.

[0043] Raw material gas first enters the sprayer 10, and under the action of the working medium liquid in the first working-medium tank 11, the compressed air is sprayed. The sprayer 10 mainly serves to clean the raw material gas, remove large oil droplets and dust in the raw material gas, and reducing the concentration of total dissolved solids in free water carried by the compressed air. In special cases, by selecting the type of working medium in the first working-medium tank 11, spraying the raw material gas can also absorb a part of the chemical solution.

[0044] The compressed air flowing out from the outlet of the sprayer 10 enters the rotary spray absorber 20. The rotary spray absorber 20 is a device having both absorption separation and drying functions. A swirling flow field can be formed inside it. After the raw material gas enters from the gas inlet, it is subjected to centrifugal force. At the same time, the working medium liquid is sprayed tangentially from the side, and is impacted and cut by the raw material gas and atomized, thereby countless working medium liquid droplets for absorption are formed. The working medium liquid droplets undergo an absorption reaction with chemical impurities-containing free water in the raw material gas. Since a swirling flow field can be formed inside the rotary spray absorber 20, the product gas is dry compressed air and is discharged from the outlet of the rotary spray absorber 20. The gas outlet of the rotary spray absorber 20 is located at the center of the top of the rotary spray absorber, and the reacted absorption liquid droplets are discharged from the drain outlet at the bottom of the rotary spray absorber.

[0045] Whether to open the first valve 13 or the second valve 12 is determined according to the chemical impurity components dissolved in the free water in the raw material gas. If the working medium liquid in the first working-medium tank 11 can be used to absorb impurities in the compressed air entering the rotary spray absorber 20, the second valve 12 is opened and the first valve 13 is closed. If the mixed working medium liquid obtained by mixing the working medium liquid in the first working-medium tank 11 and the working medium liquid in the second workingmedium tank 21 is required to absorb impurities in the compressed air entering the rotary spray absorber 20, the first valve 13 is opened and the second valve 12 is closed.

[0046] Therefore, the compressed-air purification system of this embodiment can simultaneously remove oil, solid dust, free water and chemical impurities dissolved therein carried by compressed air, and can also adapt the required impurity-removing working medium liquid according to the components of the above chemical impurities, having the advantages of wide purification range and high controllability. It can be widely used in the compressed-air energy storage industry among the fields of petroleum, chemical engineering, metallurgy, electric power, machinery, light industry, textile, automobile manufacturing, electronics, food, medicine, biochemistry, national defense, and electric power energy storage.

[0047] Further, as described above, the working medium liquid in the first working-medium tank is used for the sprayer 10, and the working medium liquid in the second working-medium tank is used for the rotary spray absorber 20. The working medium liquid in the second working-medium tank can be prepared by mixing the working medium liquids in the first working-medium tank and the second working-medium tank by opening the first valve 13 and the sixth valve 23. Therefore, the first working-medium tank contains water, alkali or acid, and the second working-medium tank contains alkali or acid. If the first working-medium tank contains water and the second workingmedium tank contains alkali or acid, then the working medium liquid in the sprayer 10 is water, and the working medium liquid in the rotary spray absorber 20 is alkali liquid or acid liquid. If the first working-medium tank contains acid and the second working-medium tank also contains acid, or the first working-medium tank contains alkali and the second working-medium tank also contains alkali, then the working medium liquid in the sprayer 10 and the working medium liquid in the rotary spray absorber 20 are both acid, or both alkali. If the first working-medium tank contains acid and the second working-medium tank contains alkali, or the first working-medium tank contains alkali and the second working-medium tank contains acid, then the working medium liquid in the sprayer 10 is acid or alkali, and the working medium liquid in the rotary spray absorber 20 may be neutral, or slightly acidic, or slightly alkaline. Thus, the purification range of the compressed-air purification system is improved.

[0048] Optionally, the water in the first working-medium tank 11 may be one of demineralized water, purified water, and distilled water.

[0049] Although the manufacturing methods and storage methods of compressed air are not exactly the same, the raw material gas will contain free water, dust, and large oil droplets, and chemical impurities are mainly divided into two cases: acidic and alkaline. The above chemical impurities are dissolved in free water, and the impurity solution after being dissolved in free water is overall acidic or overall alkaline. If the impurity solution after being dissolved in free water is overall acidic, then the first working-medium tank 11 contains water, the second working-medium tank 21 contains alkali, the first valve 13 and the sixth valve 23 are opened, and the second valve 12 is closed. By adjusting the alkali liquid working medium concentration in the second workingmedium tank 21 and the outlet head of the second high-pressure pump, the purification effect of the rotary spray absorber 20 is controlled. If the impurity solution after being dissolved in free water is overall alkaline, then the first working-medium tank 11 contains water, the second working-medium tank 21 contains acid, the first valve 13 and the sixth valve 23 are opened, and the second valve 12 is closed. By adjusting the acid liquid working medium concentration in the second working-medium tank 21 and the outlet head of the second high-pressure pump, the purification effect of the rotary spray absorber 20 is controlled. If the impurity solution after being dissolved in free water is overall neutral, then the first working-medium tank 11 contains water, the first valve 13 and the sixth valve 23 are closed, and the second valve 12 is opened. By adjusting the outlet liquid head of the second high-pressure pump, the purification effect of the rotary spray absorber 20 is controlled.

[0050] Optionally, a sixth valve 23 is provided at the outlet of the second working-medium tank 21.

[0051] Optionally, a first separator 30 is further provided between the sprayer 10 and the rotary spray absorber 20; compressed air flowing out from the outlet of the sprayer 10 enters the gas inlet of the first separator 30, and after flowing out from the outlet of the first separator 30, enters the gas inlet of the rotary spray absorber 20; the first separator 30 is configured to dry the compressed air. The compressed air after spraying will introduce excess working medium liquid. Next, the above working medium liquid is further separated by the first separator, and the amount of total dissolved solids in the liquid carried by the compressed air is further reduced. If the working medium contained in the first working-medium tank 11 is water, then the compressed air after spraying will introduce water. Next, the water in the compressed air is further separated by the separator, and the amount of total dissolved substances in the liquid carried by the compressed air is further reduced.

[0052] Optionally, the above first separator 30 is a cyclone separator or a vane separator.

[0053] Optionally, an oil separator 60 is further provided between the sprayer 10 and the rotary spray absorber 20; compressed air flowing out from the outlet of the sprayer 10 enters the gas inlet of the oil separator 60, and after flowing out from the outlet of the oil separator 60, enters the gas inlet of the rotary spray absorber 20; the oil separator 60 is configured to remove oil in the compressed air. The impurities in the compressed air produced by a compressor containing oil include oily substances, and these oily substances mainly include large oil droplets, small oil droplets, and emulsified oil droplets. Large oil droplets can be removed by the sprayer 10. If the oily substances include small oil droplets and emulsified oil droplets, they can be removed by the existing oil separator 60.

[0054] Optionally, the oil separator 60 is a coalescer, also called a coalescing separator.

[0055] Optionally, in the compressed-air purification system of this embodiment, a first separator 30 and an oil separator 60 are provided between the sprayer 10 and the rotary spray absorber 20. Compressed air flowing out from the outlet of the sprayer 10 enters the gas inlet of the first separator 30, and after flowing out from the outlet of the first separator 30, enters the oil separator 60 through a first branch; after flowing out from the outlet of the oil separator 60, it enters the gas inlet of the rotary spray absorber 20. Since the inlet precision requirement of an oil-removing coalescer is generally higher than that of an ordinary separator, the oil separator 60 is provided after the first separator 30. In a working condition without the first separator 30, the oil-removing separator may also be used alone between the sprayer 10 and the rotary spray absorber 20.

[0056] Optionally, a third valve 31 is provided on the first branch, and the third valve is configured to control on / off states of the first branch; a fifth valve 33 is provided on the outlet pipeline of the oil separator 60. The raw material gas is first separated by the first separator 30, and then oil is removed by the oil separator 60, so that the purification effect is better. By opening the third valve 31 and the fifth valve 33, the compressed air flowing out from the gas outlet of the first separator 30 is controlled to enter the oil separator 60 through the first branch.

[0057] Optionally, the gas outlet of the first separator 30 further comprises a second branch, the other end of the second branch is in communication with the gas inlet of the rotary spray absorber 20, and compressed air flowing out from the second branch enters the gas inlet of the rotary spray absorber 20. Further, a fourth valve 32 is provided on the second branch, and the fourth valve is configured to control on / off states of the second branch. If the oily substances in the impurities in the compressed air do not include small oil droplets and emulsified oil droplets, then it is not necessary to pass through the oil separator 60. At this time, the fourth valve 32 is opened, the third valve 31 and the fifth valve 33 are closed, and the compressed air flowing out from the gas outlet of the first separator 30 does not pass through the oil separator 60 but directly enters the rotary spray absorber 20.

[0058] Optionally, a slug catcher 50 is further provided before the inlet of the sprayer 10; compressed air to be purified enters the gas inlet of the slug catcher 50, and after flowing out from the gas outlet of the slug catcher 50, enters the gas inlet of the sprayer 10. When the raw material gas passes through an undulating pipeline, carried free water will accumulate at the bottom of the pipeline. After reaching a certain volume, slug flow will appear in the pipeline. Therefore, the raw material gas is first introduced into the slug catcher, so as to receive possible slug flow before the compressed air to be purified enters purification, and separate the slug flow carried by the raw material gas. The function of the slug catcher is to eliminate slug flow, provide stable transportation for downstream, and also preliminarily separate a part of large-particle oil in the raw material gas. Further, the slug catcher may be of a vessel type or a pipeline type, selected according to site conditions.

[0059] Optionally, a second separator 40 is further provided at the outlet side of the rotary spray absorber 20. Compressed air flowing out from the gas outlet of the rotary spray absorber 20 enters the gas inlet of the second separator 40, and flows out from the gas outlet of the second separator 40. The second separator 40 is configured to dry the compressed air, ensuring that the product gas is dry compressed air.

[0060] Optionally, the second separator 40 is a cyclone separator or a vane separator, selected according to working conditions. If the working conditions of the compressed air are stable, for example, when flow and pressure are stable, a cyclone separator is used; if the operating range of the working conditions is relatively wide, a vane separator is used.

[0061] Optionally, a pH detection device 22 is provided at the drain outlet of the rotary spray absorber 20, and the on / off states and opening degrees of the first valve 13 and the second valve 12 are controlled by the pH detection device 22. The on / off states and opening degrees of the first valve 13 and the second valve 12 are controlled by the pH of the drain discharged from the rotary spray absorber 20, thereby the acid / alkali concentration of the working medium liquid entering the rotary spray absorber 20 is controlled. If the pH detection device 22 detects that the pH of the drain outlet of the rotary spray absorber 20 is neutral, then the first valve 13 is closed and the second valve 12 is opened. At this time, the first working medium enters the rotary spray absorber 20, that is, the working medium of the rotary spray absorber 20 is the same as the working medium of the sprayer 10, thereby the controllability of purification is improved. If the pH detection device 22 detects that the pH of the drain outlet of the rotary spray absorber 20 is acidic or alkaline, then the second valve 12 is closed and the first valve 13 is opened. The opening degree of the first valve 13 is adjusted through the acidity and alkalinity detected by the pH detection device 22, thereby the component concentration of the working medium liquid in the second working-medium tank 21 is adjusted.

[0062] Optionally, the liquid outlet pipeline of the second working-medium tank intersects and is in communication with the first bypass branch, and a sixth valve is provided at the liquid outlet pipeline of the second working-medium tank; the on / off states and opening degrees of the first valve 13 and the second valve 12 are controlled by the pH detection device 22. The on / off states and opening degrees of the first valve 13, the second valve 12, and the sixth valve 23 are controlled by the pH of the drain discharged from the rotary spray absorber 20, thereby the acid / alkali concentration of the working medium liquid is controlled to enter the rotary spray absorber 20. If the pH detection device 22 detects that the pH of the drain outlet of the rotary spray absorber 20 is neutral, then the first valve 13, the low-pressure pump 16, and the sixth valve 23 are closed, and the second valve 12 and the second high-pressure pump 15 are opened. At this time, the first working medium enters the rotary spray absorber 20, that is, the working medium of the rotary spray absorber 20 is the same as the working medium of the sprayer 10, thereby avoiding bringing the alkali / acid solution into the raw material gas again. If the pH detection device 22 detects that the pH of the drain outlet of the rotary spray absorber 20 is acidic or alkaline, then the second valve 12 is closed, and the first valve 13, the low-pressure pump 16, the sixth valve 23, and the second high-pressure pump 15 are opened. The opening degrees of the first valve 13 and the sixth valve 23 and the outlet pressures of the low-pressure pump 16 and the second high-pressure pump 15 are adjusted through the acidity and alkalinity detected by the pH detection device 22, thereby the component concentration of the working medium liquid in the second working-medium tank 21 is adjusted.

[0063] Optionally, a first high-pressure pump is further provided on the pipeline between the first liquid outlet of the first working-medium tank 11 and the liquid inlet of the sprayer 10; and / or a second high-pressure pump is further provided on the first bypass branch; and / or a low-pressure pump is further provided on the pipeline between the second liquid outlet of the first workingmedium tank 11 and the liquid inlet of the second working-medium tank 21. Since the raw material gas in the sprayer 10 and the rotary spray absorber 20 is in a medium-pressure state and high-pressure state, a high-pressure pump is used as a power transmission component on the pipeline between the first liquid outlet of the first working-medium tank 11 and the liquid inlet of the sprayer 10, and on the pipeline of the first bypass branch. Since the connection between the second liquid outlet of the first working-medium tank 11 and the liquid inlet of the second workingmedium tank 21 is a liquid path and does not pass through compressed air, a low-pressure pump, such as a low-pressure water pump, is used between the first working-medium tank 11 and the second working-medium tank 21.

[0064] Optionally, a first cooler 17 is provided between the first liquid outlet of the first workingmedium tank 11 and the liquid inlet of the sprayer 10; and / or a second cooler 24 is provided on the pipeline at the liquid inlet of the rotary spray absorber 20. The first cooler 17 is configured to cool the working medium delivered from the outlet of the first working-medium tank 11, and the second cooler 24 is configured to cool the working medium delivered from the outlet of the second working-medium tank 21, so as to reduce gaseous water carried by the raw material gas. Both the first cooler 17 and the second cooler 24 may use heat exchangers. The heat exchangers have a cold source, and the working medium liquid is cooled by the cold source. The cold source may use a water cooler or the like.

[0065] Optionally, the sprayer 10, the rotary spray absorber 20, the first separator 30, the second separator 40, and the slug catcher 50 in the compressed-air purification system all have drain outlets, and the above drain outlets may all be connected to a main drain discharge pipe 70 through pipelines.

[0066] Optionally, in addition to the first valve, the second valve, the third valve, the fourth valve, the fifth valve, and the sixth valve, pumps, valves, temperature sensors, and pressure sensors may be provided as needed in the compressed-air purification system of this embodiment, especially before and after the sprayer 10, the rotary spray absorber 20, the first separator 30, the second separator 40, and the slug catcher 50. Those skilled in the art may provide pumps, valves, temperature sensors, pressure sensors, and other sensors according to detection needs.

[0067] Optionally, the equipment and pipelines in the above compressed-air purification system are all medium-pressure equipment and high-pressure equipment.

[0068] Embodiment 2

[0069] In this embodiment, based on Embodiment 1, the impurities of the compressed air include oil, solid substances, free water, and chemical impurities, wherein the chemical impurities are dissolved in the free water to form a chemical solution. When the temperature is lower than the freezing point, the free water and a part of the chemical solution will freeze, and another part of the chemical solution exists in a liquid form. Since the pour point of oil is higher than its freezing point, when the free water freezes into a solid, the oil will also solidify into a solid. Therefore, when the temperature is lower than the freezing point, the impurity-containing compressed air contains solid substances, solid ice, solid oil, and a liquid solution.

[0070] As shown in FIG. 2 and FIG. 3, this embodiment provides a compressed-air purification system. A first three-phase separator 80 is further provided before the inlet of the sprayer; compressed air to be purified enters the gas inlet of the first three-phase separator 80, and after flowing out from the gas outlet of the first three-phase separator 80, enters the gas inlet of the sprayer 10.

[0071] As shown in FIG. 3, the tank body of the first three-phase separator 80 is provided with a gas inlet of the first three-phase separator 88, a gas outlet of the first three-phase separator 89, a first drain outlet of the first three-phase separator 93, and a second drain outlet of the first three-phase separator 92. The tank body is provided with a weir plate 90, a liquid collection zone 97, and an ice collection zone 98. The bottom of the weir plate is connected to the inner bottom wall of the first three-phase separator, and there is a gas-phase space between the top of the weir plate and the inner top wall of the first three-phase separator; the windward side of the weir plate is the side facing the gas inlet of the first three-phase separator 88, and the leeward side of the weir plate is the back side of the windward side of the weir plate; the liquid collection zone 97 is located in the space below the windward side of the weir plate; the ice collection zone 98 is located in the space below the leeward side of the weir plate; the ice collection zone 98 is provided with a heat tracing heater, and the heat tracing heater 91 is configured to heat the ice collection zone 98; the first drain outlet of the first three-phase separator 93 is located at the bottom of the liquid collection zone 97, and the second drain outlet of the first three-phase separator 92 is located at the bottom of the ice collection zone 98.

[0072] Compressed air to be purified enters the gas inlet of the first three-phase separator 88. Solid substances, solid ice, solid oil, and liquid solution in the impurity-containing compressed air enter the liquid collection zone. As the liquid level in the liquid collection zone rises above the top of the weir plate, since solid oil, solid ice, and impurity-containing ice have low density, the solid oil and solid ice will cross over the weir plate and enter the ice collection zone. The bottom of the liquid collection zone is provided with the first drain outlet of the first three-phase separator 93, and high-density solid substances and liquid phase are discharged from the first drain outlet of the first three-phase separator 93. The ice collection zone is provided with a heat tracing heater 91, and the solid oil, solid ice, and impurity-containing ice separated into the ice collection zone can be heated by the heat tracing heater 91, so that the above solid ice and impurity-containing ice are melted into liquid, the oil restores fluidity, and they are discharged from the second drain outlet of the first three-phase separator 92 at the bottom of the ice collection zone.

[0073] Optionally, the heat tracing heater 91 may be located inside the ice collection zone or on the outer wall of the ice collection zone. A heating rod may be used inside the ice collection zone as the heat tracing heater, which has higher thermal efficiency; a heat tracing tape may also be used on the outer wall of the ice collection zone as the heat tracing heater, and the heating area of the ice collection zone is more uniform. The pipeline of the gas inlet of the first three-phase separator 88 is provided with a gas inlet valve of the first three-phase separator 84, the pipeline of the gas outlet of the first three-phase separator 89 is provided with a gas outlet valve of the first three-phase separator 82, the pipeline of the first drain outlet of the first three-phase separator 93 is provided with a second drain discharge valve of the first three-phase separator 86, and the pipeline of the second drain outlet of the first three-phase separator 92 is provided with a first drain discharge valve of the first three-phase separator 85.

[0074] The second three-phase separator 81 of this embodiment may be structurally the same as the first three-phase separator. The second three-phase separator is connected in parallel with the first three-phase separator, and when the first three-phase separator needs to be switched or repaired, the second three-phase separator is used. The pipeline of the gas inlet of the second three-phase separator 81 is provided with a gas inlet valve of the second three-phase separator 87. When the first three-phase separator needs to be switched or repaired, the gas inlet valve of the first three-phase separator 84, the gas outlet valve of the first three-phase separator 82, the first drain discharge valve of the first three-phase separator 85, and the second drain discharge valve of the first three-phase separator 86 are closed, and the gas inlet valve of the second three-phase separator 87, the gas outlet valve of the second three-phase separator 94, the first drain discharge valve of the second three-phase separator 95, and the second drain discharge valve of the second three-phase separator 96 are opened, so that the second three-phase separator is used for separation. Of course, a third three-phase separator may also be provided, connected in parallel with the first three-phase separator and the second three-phase separator.

[0075] As shown in FIG. 2, the compressed-air purification system of this embodiment comprises a first three-phase separator 80, a second three-phase separator 81, a sprayer 10, and a rotary spray absorber 20, wherein the first three-phase separator 80 and the second three-phase separator 81 are connected in parallel and both connected to the gas inlet of the sprayer 10. The gas inlet valve of the first three-phase separator 84 and the gas outlet valve of the first three-phase separator 82 are opened. Compressed air to be purified enters from the gas inlet of the first three-phase separator 88, flows out from the gas outlet of the first three-phase separator 89, and then enters the gas inlet of the sprayer 10. After flowing out from the gas outlet of the sprayer 10, it enters the gas inlet of the rotary spray absorber 20. The compressed air flowing out from the rotary spray absorber 20 is purified compressed air. The spraying device comprises a sprayer and a first working-medium tank, and the rotary spray absorption device comprises a rotary spray absorber and a second working-medium tank; the liquid inlet of the sprayer is in communication with the first liquid outlet of the first working-medium tank through a pipeline, the second liquid outlet of the first working-medium tank is in communication with the liquid inlet of the second workingmedium tank, and the liquid outlet of the second working-medium tank is in communication with the liquid inlet of the rotary spray absorber; the second liquid outlet of the first working-medium tank is further in communication with the liquid inlet of the rotary spray absorber through a first bypass branch; a first valve is provided on the pipeline between the second liquid outlet of the first working-medium tank and the liquid inlet of the second working-medium tank; a second valve is provided on the first bypass branch.

[0076] Optionally, a first separator is further provided between the sprayer and the rotary spray absorber; compressed air flowing out from the gas outlet of the sprayer enters the gas inlet of the first separator, and after flowing out from the gas outlet of the first separator, enters the gas inlet of the rotary spray absorber; the first separator is configured to dry the compressed air.

[0077] Optionally, a second separator is further provided at the outlet side of the rotary spray absorber, compressed air flowing out from the gas outlet of the rotary spray absorber enters the gas inlet of the second separator, and flows out from the gas outlet of the second separator.

[0078] As described above, a first valve 13 is provided on the pipeline between the second liquid outlet of the first working-medium tank and the liquid inlet of the second working-medium tank. Further, a low-pressure pump 16 is also provided. A second high-pressure pump 15 is provided between the liquid outlet of the second working-medium tank and the liquid inlet of the rotary spray absorber. A sixth valve 23 is further provided at the liquid outlet of the second workingmedium tank, and the outlet of the sixth valve 23 is in communication with the inlet of the second high-pressure pump 15.

[0079] Optionally, a pH detection device 22 is provided at the drain outlet of the rotary spray absorber 20, and the on / off states and opening degrees of the first valve 13, the second valve 12, and the sixth valve 23 are controlled by the pH detection device 22. The on / off states and opening degrees of the first valve 13, the second valve 12, and the sixth valve 23 are controlled by the pH of the drain discharged from the rotary spray absorber 20, thereby the acid / alkali concentration of the working medium liquid entering the rotary spray absorber 20 is controlled. If the pH detection device 22 detects that the pH of the drain outlet of the rotary spray absorber 20 is neutral, then the first valve 13, the low-pressure pump 16, and the sixth valve 23 are closed, and the second valve 12 and the second high-pressure pump 15 are opened. At this time, the first working medium enters the rotary spray absorber 20, that is, the working medium of the rotary spray absorber 20 is the same as the working medium of the sprayer 10, thereby avoiding bringing the alkali / acid solution into the raw material gas again. If the pH detection device 22 detects that the pH of the drain outlet of the rotary spray absorber 20 is acidic or alkaline, then the second valve 12 is closed, and the first valve 13, the low-pressure pump 16, the sixth valve 23, and the second high-pressure pump 15 are opened. The opening degrees of the first valve 13 and the sixth valve 23 and the outlet pressures of the low-pressure pump 16 and the second high-pressure pump 15 are adjusted through the acidity and alkalinity detected by the pH detection device 22, thereby the component concentration of the working medium liquid in the second working-medium tank 21 is adjusted.

[0080] Optionally, a first high-pressure pump 14 is further provided on the pipeline between the first liquid outlet of the first working-medium tank 11 and the liquid inlet of the sprayer 10; and / or a second high-pressure pump 15 is further provided on the first bypass branch; and / or a low-pressure pump 16 is further provided on the pipeline between the second liquid outlet of the first working-medium tank 11 and the liquid inlet of the second working-medium tank 21. Since the raw material gas in the sprayer 10 and the rotary spray absorber 20 is in a medium-pressure state and high-pressure state, a high-pressure pump is used as a power transmission component on the pipeline between the first liquid outlet of the first working-medium tank 11 and the liquid inlet of the sprayer 10, and on the pipeline of the first bypass branch. Since the connection between the second liquid outlet of the first working-medium tank 11 and the liquid inlet of the second workingmedium tank 21 is a liquid path and does not pass through compressed air, a low-pressure pump, such as a low-pressure water pump, is used between the first working-medium tank 11 and the second working-medium tank 21.

[0081] Optionally, a first cooler 17 is provided between the first liquid outlet of the first workingmedium tank 11 and the liquid inlet of the sprayer 10; and / or a second cooler 24 is provided on the pipeline at the liquid inlet of the rotary spray absorber 20. The first cooler 17 is configured to cool the working medium delivered from the outlet of the first working-medium tank 11, and the second cooler 24 is configured to cool the working medium delivered from the outlet of the second working-medium tank 21, so as to reduce gaseous water carried by the raw material gas. Both the first cooler 17 and the second cooler 24 may use heat exchangers. The heat exchangers have a cold source, and the working medium liquid is cooled by the cold source. The cold source may use a water cooler or the like.

[0082] Optionally, the equipment and pipelines in the above compressed-air purification system are all medium-pressure equipment and high-pressure equipment.

[0083] The compressed-air purification system of this embodiment can be adapted to a working condition in which the temperature of the raw material gas is lower than the freezing point, and can simultaneously remove solid substances, solid ice, solid oil, solid impurity ice, and liquid impurity solution carried by compressed air. It can also adapt the required impurity-removing working medium liquid according to the components of chemical impurities, having the advantages of wide purification range, wide applicable geographical range, and high controllability.

[0084] Obviously, the above embodiments of the present application are merely examples for clearly explaining the present application, and are not intended to limit the implementation manners of the present application. For those of ordinary skill in the art, other different forms of changes or modifications may also be made on the basis of the above description. It is unnecessary and impossible to exhaustively list all implementation manners here. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present application shall be included within the protection scope of the claims of the present application.

Claims

1. A compressed-air purification system, characterized in that the system comprises a spraying device and a rotary spray absorption device, wherein the spraying device comprises a sprayer and a first working-medium tank, and the rotary spray absorption device comprises a rotary spray absorber and a second working-medium tank;a liquid inlet of the sprayer is in communication with a first liquid outlet of the first workingmedium tank through a pipeline, a second liquid outlet of the first working-medium tank is in communication with a liquid inlet of the second working-medium tank, and a liquid outlet of the second working-medium tank is in communication with a liquid inlet of the rotary spray absorber through a pipeline; the second liquid outlet of the first working-medium tank is further in communication with the liquid inlet of the rotary spray absorber through a pipeline of a first bypass branch; a first valve is provided on the pipeline between the second liquid outlet of the first working-medium tank and the liquid inlet of the second working-medium tank; a second valve is provided on the first bypass branch; andcompressed air to be purified enters a gas inlet of the sprayer, flows out from a gas outlet of the sprayer, and then enters a gas inlet of the rotary spray absorber.

2. The compressed-air purification system according to claim 1, characterized in that a first separator is further provided between the sprayer and the rotary spray absorber;compressed air flowing out from the gas outlet of the sprayer enters a gas inlet of the first separator, and after flowing out from a gas outlet of the first separator, enters the gas inlet of the rotary spray absorber; andthe first separator is configured to dry the compressed air.

3. The compressed-air purification system according to claim 2, characterized in that an oil separator is further provided between the first separator and the rotary spray absorber; the gas outlet of the first separator is in communication with a gas inlet of the oil separator through a first branch, and a gas outlet of the oil separator is in communication with the gas inlet of the rotary spray absorber; a third valve is provided on the first branch; a fifth valve is provided at the gas outlet of the oil separator.

4. The compressed-air purification system according to claim 3, characterized in that the gas outlet of the first separator further comprises a second branch, one end of the second branch is incommunication with the gas outlet of the first separator, and the other end of the second branch is in communication with an outlet pipeline of the fifth valve, and compressed air flowing out from the second branch enters the gas inlet of the rotary spray absorber; a fourth valve is provided on the second branch.

5. The compressed-air purification system according to claim 1, characterized in that a slug catcher is further provided before an inlet of the sprayer; andcompressed air to be purified enters a gas inlet of the slug catcher, and after flowing out from a gas outlet of the slug catcher, enters the gas inlet of the sprayer.

6. The compressed-air purification system according to claim 1, characterized in that a second separator is further provided at an outlet side of the rotary spray absorber, compressed air flowing out from a gas outlet of the rotary spray absorber enters a gas inlet of the second separator, and flows out from a gas outlet of the second separator.

7. The compressed-air purification system according to claim 1, characterized in that the first working-medium tank contains water, alkali or acid, and the second working-medium tank contains alkali or acid.

8. The compressed-air purification system according to claim 1, characterized in that a sixth valve is provided at an outlet of the second working-medium tank; the first working-medium tank contains water, the second working-medium tank contains alkali, the first valve and the sixth valve are opened, and the second valve is closed, for purifying compressed air.

9. The compressed-air purification system according to claim 1, characterized in that a sixth valve is provided at the outlet of the second working-medium tank; the first working-medium tank contains water, the second working-medium tank contains acid, the first valve and the sixth valve are opened, and the second valve is closed, for purifying compressed air.

10. The compressed-air purification system according to claim 1, characterized in that a sixth valve is provided at the outlet of the second working-medium tank; the first working-medium tank contains water, the first valve and the sixth valve are closed, and the second valve is opened, for purifying compressed air.

11. The compressed-air purification system according to claim 2 or 6, characterized in that the first separator is a cyclone separator or a vane separator; and / or the second separator is a cyclone separator or a vane separator.

12. The compressed-air purification system according to claim 1, characterized in that a first cooler is provided between the first liquid outlet of the first working-medium tank and the liquid inlet of the sprayer; and / or a second cooler is provided on the pipeline at the liquid inlet of the rotary spray absorber.

13. The compressed-air purification system according to claim 1, characterized in that a first high-pressure pump is further provided on the pipeline between the first liquid outlet of the first working-medium tank and the liquid inlet of the sprayer;and / or a second high-pressure pump is provided at the liquid inlet of the rotary spray absorber, an outlet of the second high-pressure pump is in communication with the liquid inlet of the rotary spray absorber, a sixth valve is provided at a liquid outlet pipeline of the second working-medium tank, an inlet of the sixth valve is in communication with the liquid outlet of the second workingmedium tank, an outlet of the sixth valve is in communication with an outlet of the second valve, and both the outlet of the sixth valve and the outlet of the second valve are in communication with an inlet of the second high-pressure pump; and / or a low-pressure pump is further provided on the pipeline between the second liquid outlet of the first working-medium tank and the liquid inlet of the second working-medium tank.

14. The compressed-air purification system according to claim 13, characterized in that a pH detection device is provided at a drain outlet of the rotary spray absorber;the first valve and the sixth valve are controlled to open and the second valve is controlled to close by the pH detection device; or the second valve is controlled to open and the first valve and the sixth valve are controlled to close by the pH detection device;and / or outlet pressures of the low-pressure pump and the second high-pressure pump are controlled by the pH detection device.

15. The compressed-air purification system according to claim 3, characterized in that the oil separator is an oil-removing coalescer.

16. The compressed-air purification system according to claim 1, characterized in that a firstthree-phase separator is further provided before the inlet of the sprayer;compressed air to be purified enters a gas inlet of the first three-phase separator, and after flowing out from a gas outlet of the first three-phase separator, enters the gas inlet of the sprayer.

17. The compressed-air purification system according to claim 16, characterized in that the first three-phase separator comprises a weir plate, a liquid collection zone, and an ice collection zone;a bottom of the weir plate is connected to an inner bottom wall of the first three-phase separator, and there is a gas-phase space between a top of the weir plate and an inner top wall of the first three-phase separator;a windward side of the weir plate is a side facing the gas inlet of the first three-phase separator, and a leeward side of the weir plate is a back side of the windward side of the weir plate; the liquid collection zone is located in a space below the windward side of the weir plate; the ice collection zone is located in a space below the leeward side of the weir plate; the ice collection zone is provided with a heat tracing heater, and the heat tracing heater is configured to heat the ice collection zone;a first drain outlet of the first three-phase separator is located at a bottom of the liquid collection zone, and a second drain outlet of the first three-phase separator is located at a bottom of the ice collection zone.

18. The compressed-air purification system according to claim 16, characterized in that a second three-phase separator is further provided before the inlet of the sprayer, and the second three-phase separator is connected in parallel with the first three-phase separator;compressed air to be purified enters the gas inlet of the first three-phase separator, and after flowing out from the gas outlet of the first three-phase separator, enters the gas inlet of the sprayer; or compressed air to be purified enters a gas inlet of the second three-phase separator, and after flowing out from a gas outlet of the second three-phase separator, enters the gas inlet of the sprayer.

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