Instrument air on-line water removal system

Abstract

The utility model discloses an instrument air on-line water removal system which comprises an air compressor, and an outlet of the air compressor is sequentially communicated with a buffer tank, a cold dryer, an adsorption device and an air storage tank through air pipelines. The adsorption device comprises a first adsorption tower and a second adsorption tower which are connected in parallel. The system effectively removes moisture in compressed air, reduces the dew-point temperature and ensures that the dew-point temperature of the compressed air is less than or equal to-40 DEG C by utilizing the principle of freeze dehydration and adsorption dehydration, so that the dryness of air used by pneumatic equipment is improved, and the conditions of corrosion, blockage and freezing in pipelines, valves or equipment caused by the fact that water vapor is condensed into water at low temperature are avoided; the service life of equipment is prolonged, the whole system is interlocked through the PLC, and automatic operation is achieved.

Description

TECHNICAL FIELD

[0001] The utility model relates to the field of chemical production equipment, concretely relates to an instrument air on -line water removal system. BACKGROUND

[0002] As an important resource in industrial production, instrument air is a key factor to ensure the stable and efficient operation of industrial automation control system, which is mainly used for driving and controlling pneumatic equipment, and as auxiliary gas in some process, such as the main power source of pneumatic actuators such as air cylinder, pneumatic valve, etc., through controlling the pressure and flow of gas, the precise control and action of equipment are realized.

[0003] Instrument air is usually made by air compressor from atmospheric air through a series of processing processes such as compression, in the compression process, the water, oil mist and impurities in the air are gradually removed, and the instrument air made can meet the strict requirements of instrument and control system. But in the process of instrument air preparation, due to the high water content of compressed air, the processing difficulty is big, so the water content of the instrument air prepared is also high, which will cause the following effects on equipment and facilities: (1) the water in the instrument air will cause the corrosion of the internal pneumatic equipment and pipeline, especially the parts sensitive to water, such as pneumatic valve, air cylinder, instrument and electronic elements of control system, long-term exposure in high humidity environment will accelerate the wear and failure of these parts, reduce the reliability and efficiency of the whole system, and accelerate the damage of equipment; (2) the pneumatic control system depends on accurate pressure and flow control, but the existence of water will change the volume and compressibility of gas, affect the accurate transmission of pneumatic signal, cause inaccurate feedback of control system, affect the control accuracy of production process and product quality, cause the inaccuracy of pneumatic instrument precision and control; (3) in low temperature environment, the water in the instrument air may condense into ice in the pipeline or equipment, block the air path, limit the airflow, and even cause equipment damage, in extreme cases, ice may also cause pipeline rupture, especially in dangerous chemical source device, it is easy to cause safety accidents; (4) more water will increase the maintenance frequency and cost of equipment, including replacing the corroded parts, cleaning or replacing the filter, desiccant, etc., and the production loss caused by failure downtime, the cost is high; (5) in some industries with strict production environment requirements, such as air conveying device of polyvinyl chloride resin, the water in the instrument air will directly cause the quality problems such as resin moisture and caking, which does not meet the use requirements. CONTENT OF THE UTILITY MODEL

[0004] The utility model provides an instrument air on -line water removal system, the purpose is to solve the problem of high water content in the process of instrument air preparation, causing the corrosion of pneumatic equipment and pipeline, affecting the control accuracy and accelerating the damage of equipment.

[0005] In order to achieve the purpose, the utility model adopts the following technical scheme:

[0006] The utility model provides an instrument air on-line water removal system, including air compressor, and the air compressor export is connected with buffer tank, cold dryer, adsorption device and air storage tank through air pipeline in proper order.

[0007] Further, the adsorption device includes two parallel first adsorption tower and second adsorption tower, and the air pipeline, which is communicated with the first adsorption tower and the second adsorption tower, is respectively provided with a cut-off valve on the cold dryer, a check valve is arranged on the air pipeline at the top of the first adsorption tower and the second adsorption tower, and a cut-off valve is further arranged on the air pipeline at the top, respectively; The first adsorption tower and the second adsorption tower are both provided with a time relay.

[0008] Further, the bottom of the buffer tank, the cold dryer and the air storage tank is communicated with a first drainage pipeline, and the first drainage pipeline is provided with an automatic drainage valve.

[0009] Further, the bottom of the first adsorption tower and the second adsorption tower is communicated with a second drainage pipeline, and the second drainage pipeline is respectively provided with a cut-off valve.

[0010] Further, a first branch pipeline is communicated on the air pipeline between the first adsorption tower and the second adsorption tower, and an electric heater is arranged on the first branch pipeline.

[0011] Further, a second branch pipeline is communicated on the air pipeline at the outlet of the cold dryer, and a first valve is arranged on the second branch pipeline.

[0012] Further, a second valve is arranged on the air pipeline between the adsorption device and the air storage tank.

[0013] Further, a silencer is arranged on the second drainage pipeline.

[0014] Further, a thermometer is arranged on the air pipeline at the outlet of the cold dryer.

[0015] Further, the time relay is electrically connected with the signal input end of the PLC programmable controller, and the signal output end of the PLC programmable controller is respectively electrically connected with all cut-off valves, the first valve, the second valve, the electric heater, the automatic drainage valve, the thermometer, the silencer and the check valve.

[0016] Compared with the prior art, the utility model has the beneficial effects as follows:

[0017] The online water removing system provided by the utility model is sequentially communicated with a buffer tank, a cold dryer, an adsorption device and an air storage tank on the air pipeline at the outlet of the air compressor, utilizes the principle of freezing dehydration+adsorption dehydration, effectively removes the water in the compressed air, reduces the dew point temperature, guarantees that the dew point temperature of the compressed air is ≤-40 DEG C, thereby improving the dryness of the air used by the pneumatic equipment, avoids the condensation of water vapor into water at low temperature, causes the corrosion, blockage and icing of the pipeline, valve or equipment, prolongs the service life of the equipment. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 It is an online water removing system structure schematic view of the utility model;

[0019] In the drawing: 1: air compressor; 2: buffer tank; 3: cold dryer; 4: adsorption device; 5: air storage tank; 6: PLC programmable controller; A: first adsorption tower; B: second adsorption tower; G1: air pipeline; G2: first drainage pipeline; G3: second drainage pipeline; G4: first branch pipeline; G5: second branch pipeline; Q1, Q2, Q3, Q4, Q5, Q6: cut-off valve; P1: first valve; P2: second valve; J: electric heater; H: automatic drainage valve; T: thermometer; X: silencer; Z: check valve. DETAILED DESCRIPTION

[0020] The utility model will be further described below in combination with the drawings:

[0021] For example, Figure 1As shown, the utility model is a kind of instrument air on-line water removal system, including the air compressor 1 of being located in the most front end of system, air compressor 1 outlet is sequentially linked with buffer tank 2, cold dryer 3, adsorption device 4 and air storage tank 5 by air pipeline G1 intercommunication.Specifically, air compressor 1 selects screw air compressor, utilizes a pair of intermeshing helical rotor to rotate in shell, with the rotation of rotor, the volume of cavity between screw gradually reduces, realizes the continuous compression of gas, and oil-gas mixture after compression enters oil-gas separation tank, by collision, interception, gravity separation etc., most of oil is separated, and cleaner compressed air is obtained, and the whole machine has air cooling, oil separation function.Buffer tank 2 provides a temporary storage compressed air space in compressed air system, and it plays the role of smoothing pressure fluctuation, guaranteeing downstream gas equipment pressure stability.Cold dryer 3 main role is to reduce the moisture content in compressed air, ensure the normal operation of pneumatic equipment and prolong equipment life, simultaneously avoid the problems such as corrosion, freezing, equipment failure and product pollution caused by moisture.Adsorption device 4 removes moisture, oil mist and impurities to achieve different application required air quality standards.Air storage tank 5 is to store compressed air, and air storage tank 5 can effectively slow down air pressure fluctuation, provide stable pressure for downstream gas equipment, improve the stability of production process and product quality.

[0022] The adsorption device 4 includes two parallel first adsorption tower A and second adsorption tower B, and the first adsorption tower A and the second adsorption tower B are both air volume 600 Nm 3The existing adsorption tower with a carbon steel shell, a grid plate at the bottom, adsorbent in the middle and a grid plate at the top of the adsorbent, has a high adsorption capacity. The adsorbent is active alumina with a high specific surface area, which can effectively adsorb moisture in the air. When the humid compressed air passes through the first adsorption tower A and the second adsorption tower B, the moisture is captured by the micropores on the surface of the adsorbent, thereby achieving the effect of drying the air. During system operation, the replacement condition of the adsorbent can be determined according to the pressure difference between the inlet and outlet of the adsorption tower. When the pressure difference is greater than 0.1 Mpa, the adsorbent needs to be replaced. The air pipeline G1 connected to the first adsorption tower A and the second adsorption tower B of the cold dryer 3 is respectively provided with a shut-off valve Q2 and a shut-off valve Q5. The air pipeline G1 at the top of the first adsorption tower A and the second adsorption tower B is respectively provided with a check valve Z to prevent air from being mixed during the adsorption and regeneration processes of the two towers. The air pipeline G1 at the top is also respectively provided with a shut-off valve Q1 and a shut-off valve Q4. The bottom of the first adsorption tower A and the second adsorption tower B is connected with a second drainage pipeline G3, and the second drainage pipeline G3 is respectively provided with a shut-off valve Q3 and a shut-off valve Q6. To avoid noise pollution in the workshop and the environment, the second drainage pipeline G3 is also provided with a silencer X. The first adsorption tower A and the second adsorption tower B are respectively provided with a time relay. The air pipeline G1 between the first adsorption tower A and the second adsorption tower B is connected with a first branch pipeline G4 through a three-way connector. The first branch pipeline G4 is provided with an electric heater J. The electric heater J uses 380V alternating current power to heat. According to the principle of high-pressure low-temperature water removal and low-pressure high-temperature regeneration, the moisture in the adsorption device 4 is discharged from the bottom of the adsorption device 4 through hot water, ensuring that the temperature of the adsorption device 4 meets the standard during the regeneration and drainage process.

[0023] The bottom of the buffer tank 2, the cold dryer 3 and the air storage tank 5 is connected with a first drainage pipeline G2, and the first drainage pipeline G2 is respectively provided with an automatic drainage valve H. The automatic drainage valve H of the cold dryer 3 is an electrically controlled timing drainage valve, which automatically opens and closes the drainage port according to the preset time interval to perform regular drainage. The automatic drainage valve H at the bottom of the air storage tank 5 is a float ball type automatic drainage valve, which has a float ball inside. As the condensed water accumulates in the drainage cavity, the float ball also rises. When the water level reaches a predetermined height, the float ball drives a connecting rod or a magnetic coupling device to open the drainage valve, allowing the condensed water to be discharged. As the water level drops, the float ball falls back, and the drainage valve is automatically closed under the action of a spring or gravity to prevent compressed air leakage. The air pipeline G1 at the outlet of the cold dryer 3 is provided with a thermometer T, and the air pipeline G1 is also connected with a second branch pipeline G5, and the second branch pipeline G5 is provided with a first valve P1. The air pipeline G1 between the adsorption device 4 and the air storage tank 5 near the air storage tank 5 is provided with a second valve P2. The first valve P1 and the second valve P2 are used to send compressed air to the air storage tank 5 through the second branch pipeline G5 in the case of adsorption tower failure or normal maintenance, to ensure continuous air supply and ensure the continuity of production.

[0024] The time relay is electrically connected to the signal input terminal of the PLC programmable controller 6. The signal output terminal of the PLC programmable controller 6 is electrically connected to the shut-off valves Q1, Q2, Q3, Q4, Q5, and Q6, the first valve P1, the second valve P2, the electric heater J, the automatic drain valve H, the thermometer T, the silencer X, and the check valve Z, respectively. During operation, the time relay records the running time of the first adsorption tower A and the second adsorption tower B. When the set time is reached, the time relay feeds a signal back to the PLC programmable controller 6. The PLC programmable controller 6 receives the signal and controls the switching operation of the first adsorption tower A and the second adsorption tower B. Specifically, the PLC programmable controller 6 switches the standby adsorption tower by controlling shut-off valves Q1, Q2, Q6, or shut-off valves Q3, Q4, and Q5, ensuring that while one tower is performing adsorption drying, the other tower is performing regeneration drainage treatment, thus ensuring a continuous supply of compressed air. During operation, when the adsorption tower malfunctions or is under normal maintenance, the PLC programmable controller 6 controls the second valve P2 to close, and uses the first valve P1 to send compressed air to the air storage tank 5 through the second branch pipeline G5, ensuring continuous air supply and maintaining production continuity. Simultaneously, the PLC programmable controller 6 also controls the operation of the electric heater J, automatic drain valve H, thermometer T, silencer X, and check valve Z. The electric heater J ensures the temperature meets standards during the regeneration drainage process of the adsorption unit 4; the automatic drain valve H drains water periodically; the thermometer T monitors the temperature of the compressed air after cooling and drying; the silencer X prevents noise pollution in the plant and environment; and the check valve Z prevents cross-contamination of air between the two towers during adsorption and regeneration. This achieves signal interlocking and automated operation.

[0025] When working, the air pipeline G1 at the outlet of the air compressor 1 is inserted into the bottom of the buffer tank 2, and the compressed air enters from the top to the bottom of the buffer tank 2, the air pipeline G1 at the top of the buffer tank 2 is communicated with the inlet of the cold dryer 3, and the automatic drainage of the compressed air is realized. The cold dryer 3 selects an air-cooled freon refrigeration unit, the compressed air at the outlet of the buffer tank 2 is introduced into the evaporator of the cold dryer 3, and heat exchange is carried out with the low-temperature refrigerant. In this process, the temperature of the compressed air is significantly reduced, close to its dew point temperature, so that the moisture in the air condenses into liquid water and is precipitated. The air pipeline G1 at the outlet of the cold dryer 3 is provided with a thermometer T, which is convenient for observing the temperature index of the compressed air after cold drying, and the index range is required to be 10-15℃. By referring to the thermometer T, the running load of the cold dryer 3 can be adjusted in time to ensure the normal operation of the drainage system. The cold dryer 3 is communicated with two parallel first adsorption tower A and second adsorption tower B respectively, one standby and one use, switching operation, to ensure that while one tower is adsorbing and drying, the other tower is regenerating and draining water, so that the continuous supply of compressed air can be ensured to meet the production needs. The compressed air at the outlet of the cold dryer 3 enters from below the first adsorption tower A or the second adsorption tower B, and the dried compressed air is transported to the air storage tank 5 through the air pipeline G1 at the top outlet of the first adsorption tower A or the second adsorption tower B, and enters from the bottom of the air storage tank 5 and is transported to the user through the air pipeline G1 from the top of the air storage tank 5.

[0026] The adsorption operation time of the first adsorption tower A is set to 1h, and the regeneration time of the second adsorption tower B is set to 1h, and the synchronous switching operation is realized through the PLC programmable controller. The switching logic is as follows: when the first adsorption tower A is adsorbed and the second adsorption tower B is regenerated, the PLC programmable controller synchronously controls to close the cut-off valve Q3, open the cut-off valves Q1 and Q2, close the cut-off valves Q4 and Q5, and open the cut-off valve Q6. After 1h of operation, the time relay transmits a signal to the PLC programmable controller, and the PLC programmable controller receives the signal to switch the second adsorption tower B to adsorb and the first adsorption tower A to regenerate. At this time, the PLC programmable controller synchronously controls to close the cut-off valves Q1, Q2 and Q6, and opens Q3, Q4 and Q5. The above control program can be set to cycle operation mode through the PLC programmable controller.

[0027] The dew point temperature of the compressed air required by the instrument equipment is ≤-40℃, so the dew point temperature of the compressed air is measured during the system operation to confirm whether the water content of the compressed air meets the standard. The measured dew point temperature is-52℃, which indicates that the dew point temperature of the compressed air meets the requirements, and the water content meets the standard, and the instrument air prepared by the system meets the requirements, solving the problem of high water content in the instrument air preparation process, prolonging the service life of the equipment, and improving the test accuracy.

Claims

1. An instrument air on-line water removal system comprising an air compressor (1), characterized in that: The air compressor (1) outlet is sequentially connected with the buffer tank (2), the cold dryer (3), the adsorption device (4) and the air storage tank (5) through the air pipeline (G1); the adsorption device (4) comprises two parallel first adsorption towers (A) and second adsorption towers (B), the cold dryer (3) is provided with a cut-off valve Q2 and a cut-off valve Q5 on the air pipeline (G1) communicated with the first adsorption tower (A) and the second adsorption tower (B) respectively, the air pipeline (G1) on the top of the first adsorption tower (A) and the second adsorption tower (B) is provided with a check valve (Z), and the air pipeline (G1) on the top is further provided with a cut-off valve Q1 and a cut-off valve Q4 respectively; the first adsorption tower (A) and the second adsorption tower (B) are provided with time relays.

2. An instrument air on-line water removal system as claimed in claim 1, wherein: The buffer tank (2), the cold dryer (3) and the air storage tank (5) are all communicated with the first drainage pipeline (G2) at the bottom, and the first drainage pipeline (G2) is provided with an automatic drainage valve (H).

3. An instrument air on-line water removal system as claimed in claim 2, wherein: The first adsorption tower (A) and the second adsorption tower (B) are communicated with the second drainage pipeline (G3) at the bottom, and the second drainage pipeline (G3) is provided with a cut-off valve Q3 and a cut-off valve Q6 respectively.

4. An instrument air on-line water removal system as claimed in claim 3, wherein: The first adsorption tower (A) and the second adsorption tower (B) are communicated through the air pipeline (G1), and the air pipeline (G1) is communicated with the first branch pipeline (G4), and the first branch pipeline (G4) is provided with an electric heater (J).

5. An instrument air on-line water removal system as claimed in claim 4, wherein: The air pipeline (G1) at the outlet of the cold dryer (3) is communicated with the second branch pipeline (G5), and the second branch pipeline (G5) is provided with a first valve (P1).

6. An instrument air on-line water removal system as claimed in claim 5, wherein: The air pipeline (G1) between the adsorption device (4) and the air storage tank (5) is provided with a second valve (P2).

7. An instrument air on-line water removal system as claimed in claim 6, wherein: The second drainage pipeline (G3) is provided with a silencer (X).

8. An instrument air on-line water removal system as claimed in claim 7, wherein: The air pipeline (G1) at the outlet of the cold dryer (3) is provided with a thermometer (T).

9. An instrument air on-line water removal system as claimed in claim 8, wherein: The time relay is electrically connected with the signal input end of the PLC programmable controller (6), and the signal output end of the PLC programmable controller (6) is electrically connected with the cut-off valve Q1, the cut-off valve Q2, the cut-off valve Q3, the cut-off valve Q4, the cut-off valve Q5, the cut-off valve Q6, the first valve (P1), the second valve (P2), the electric heater (J), the automatic drainage valve (H), the thermometer (T), the silencer (X) and the check valve (Z).

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