Combined vacuum-pumping system for hydrogen peroxide production line

Abstract

The utility model discloses a hydrogen peroxide production line combined vacuum-pumping system, which is characterized in that a vacuum-pumping main pipe outlet is connected with an extraction opening of a roots vacuum pump, an exhaust opening of the roots vacuum pump is connected with an extraction opening of a liquid ring vacuum pump in series, and an exhaust opening of the liquid ring vacuum pump is connected with a gas inlet at the top of the left side of a gas-liquid separation tank; a right top exhaust port of the gas-liquid separation tank is connected with a tail gas collection device; a vertical middle partition plate is arranged in an inner cavity of the gas-liquid separation tank and divides a tank body into a left cavity and a right cavity, and an overflow channel is reserved between the middle partition plate and the tank top. A pure water replenishing pipe is connected to the left cavity of the gas-liquid separation tank through a pure water replenishing valve; a water outlet in the lower part of the left cavity of the gas-liquid separation tank is connected with a hot side inlet of a cooler through a filter; a hot side outlet of the cooler is connected with a working liquid inlet of a liquid ring vacuum pump; and a water outlet at the bottom of the right cavity of the gas-liquid separation tank is connected with a wastewater discharge pipe through a wastewater discharge valve. According to the system, the vacuum degree and the air exhaust efficiency can be improved, automatic adjustment of the vacuum degree and automatic separation and discharge of waste liquid are achieved, and meanwhile energy consumption is reduced.

Description

Technical Field

[0001] This utility model relates to a hydrogen peroxide production line, and more particularly to a combined vacuum system for a hydrogen peroxide production line, belonging to the technical field of vacuum equipment. Background Technology

[0002] Certain chemical reactions or physical separation processes require vacuum conditions, which are typically achieved using vacuum pumping equipment. For example, in hydrogen peroxide production plants, the circulating working fluid may contain some water during the extraction process when mixed with water. This water is detrimental to subsequent reactions, so it needs to be removed by vacuum dehydration. Currently, liquid ring vacuum pumps and Roots vacuum pumps are the most commonly used vacuum pumping equipment in hydrogen peroxide plants for creating a vacuum environment.

[0003] The working principle of a liquid ring vacuum pump is to use the liquid in the pump body as the working fluid, and achieve gas intake, compression, and exhaust by changing the volume of the pump chamber. It belongs to the category of variable displacement vacuum pumps. Liquid ring vacuum pumps have advantages such as simple structure, uniform gas intake, stable and reliable operation, simple operation, and convenient maintenance. Due to their structural design, liquid ring vacuum pumps also have disadvantages such as low efficiency and low ultimate vacuum capability. To save water in liquid ring vacuum pumps, a gas-liquid separator is often required to facilitate the reuse of the working fluid. However, if the gas-liquid separation effect is poor, waste liquid entering the liquid ring pump will cause low vacuum efficiency, equipment damage due to insufficient working fluid, and difficulties in collecting exhaust gas, resulting in excessive emissions. Therefore, manual replenishment of working fluid and discharge of waste liquid in the gas-liquid separator are required, making operation cumbersome and unsafe.

[0004] The working principle of a Roots vacuum pump is to move gas using two rotating impellers. The rotation of the impellers compresses and discharges the gas to create a vacuum; it is also a type of positive displacement vacuum pump. Roots vacuum pumps have advantages such as simple structure, quick start-up, large pumping capacity, high efficiency, low energy consumption, and low noise. However, Roots vacuum pumps have disadvantages such as generating significant heat of compression when operating under high pressure differentials, which cannot be dissipated spontaneously, and being prone to damage due to overheating.

[0005] To improve the vacuuming capacity of the production line, in some cases, liquid ring vacuum pumps and Roots vacuum pumps are used in series. However, there are some problems: changes in production load or fluctuations in production process can make it difficult to adjust the vacuum level of the vacuum unit and result in high energy consumption; frequent human intervention is required when the vacuum level fluctuates or other abnormal conditions occur, and the low degree of automation makes operation difficult and increases the burden on staff; especially in chemical production facilities with certain hazards, such as hydrogen peroxide production lines, the excessive time that staff spend on site can lead to health and safety risks. Utility Model Content

[0006] The purpose of this section is to outline some aspects of embodiments of the present invention and to briefly describe some preferred embodiments. Simplifications or omissions may be made in this section, as well as in the abstract and title of this application, and such simplifications or omissions should not be construed as limiting the scope of the present invention.

[0007] In view of the problems existing in the above and / or prior art, this utility model is proposed.

[0008] The purpose of this invention is to overcome the problems existing in the prior art and provide a combined vacuum system for a hydrogen peroxide production line, which can improve the vacuum level and pumping efficiency of the entire system, realize automatic adjustment of vacuum level and automatic separation and discharge of waste liquid, and reduce energy consumption.

[0009] To solve the above technical problems, this utility model provides a combined vacuum system for a hydrogen peroxide production line, including a vacuum main pipe. The outlet of the vacuum main pipe is connected to the suction port of a Roots vacuum pump. The exhaust port of the Roots vacuum pump is connected in series with the suction port of a liquid ring vacuum pump. The exhaust port of the liquid ring vacuum pump is connected to the air inlet at the top left side of the gas-liquid separator. The exhaust port at the top right side of the gas-liquid separator is connected to a tail gas collection device. The gas-liquid separator has a vertical partition plate that divides the tank into left and right chambers. An overflow channel is provided between the partition plate and the top of the tank. A pure water supply pipe is connected to the left chamber of the gas-liquid separator through a pure water supply valve. The lower outlet of the left chamber of the gas-liquid separator is connected to the hot side inlet of a cooler through a filter. The hot side outlet of the cooler is connected to the working fluid inlet of the liquid ring vacuum pump. The bottom drain outlet of the right chamber of the gas-liquid separator is connected to a wastewater discharge pipe through a wastewater discharge valve.

[0010] As an improvement to this utility model, the vent of the liquid ring vacuum pump and the bottom left outlet of the gas-liquid separator are also connected to the wastewater discharge pipe, and the outlet of the wastewater discharge pipe is connected to the wastewater treatment station.

[0011] As a further improvement of this utility model, the outlet of the vacuum manifold is provided with an inlet pressure transmitter, and the motor speed of the Roots vacuum pump is controlled by the measured value of the inlet pressure transmitter.

[0012] As a further improvement of this utility model, the left chamber of the gas-liquid separator is equipped with a left level gauge, and the pure water replenishment valve and the liquid ring vacuum pump are both controlled by the level measured by the left level gauge; the right chamber of the gas-liquid separator is equipped with a right level gauge, and the wastewater discharge valve is controlled by the level measured by the right level gauge.

[0013] As a further improvement of this utility model, the cooling water inlet of the Roots vacuum pump casing is connected to the cooling water inlet pipe, and the cooling water outlet of the Roots vacuum pump casing is equipped with a Roots vacuum pump cooling water flow meter and connected to the cooling water outlet pipe; the cold side inlet of the cooler is connected to the cooling water inlet pipe, and the cold side outlet of the cooler is also connected to the cooling water outlet pipe.

[0014] As a further improvement of this utility model, the main contact of the main circuit AC contactor and a thermal relay are connected in series in the main circuit of the liquid ring vacuum pump motor. The control circuit of the liquid ring vacuum pump motor is connected in series with a fuse, the normally open contact of the second intermediate relay, the coil of the main circuit AC contactor, and the normally closed contact of the thermal relay. The coil of the second intermediate relay is connected to the liquid ring vacuum pump control port of the PLC controller. The normally open contact of the main circuit AC contactor is connected in series in the liquid ring vacuum pump operation feedback port of the PLC controller, and the normally open contact of the thermal relay is connected in series in the liquid ring vacuum pump fault feedback port of the PLC controller.

[0015] As a further improvement of this utility model, the motor of the Roots vacuum pump is controlled by a frequency converter. The normally open contact of the third intermediate relay is connected in series to the DI1 control terminal of the frequency converter, and the coil of the third intermediate relay is connected in series to the Roots vacuum pump control signal output terminal of the PLC controller. The speed signal output port of the PLC controller is connected to the AI1 control terminal of the frequency converter. The DO1 control terminal of the frequency converter is connected to the running signal input port of the PLC controller, and the DO2 control terminal of the frequency converter is connected to the fault signal feedback port of the PLC controller.

[0016] As a further improvement of this utility model, the signal line of the left level gauge is connected to the left level signal input port of the PLC controller; the power supply circuit of the pure water replenishment valve is connected in series with the normally open contact of the fourth intermediate relay; the coil of the fourth intermediate relay is connected in series with the pure water replenishment control port of the PLC controller; the normally open contact of the valve position switch of the pure water replenishment valve is connected in series with the pure water replenishment status feedback port of the PLC controller; the signal line of the right level gauge is connected to the right level input port of the PLC controller; the power supply circuit of the wastewater discharge valve is connected in series with the normally open contact of the fifth intermediate relay; the coil of the fifth intermediate relay is connected in series with the wastewater discharge control port of the PLC controller; the normally open contact of the valve position switch of the wastewater discharge valve is connected in series with the wastewater discharge status feedback port of the PLC controller.

[0017] As a further improvement of this utility model, the signal line of the inlet pressure transmitter is connected to the inlet pressure signal input terminal of the PLC controller, the signal line of the Roots vacuum pump cooling water flow meter is connected to the Roots vacuum pump cooling water flow signal input terminal of the PLC controller, the signal line of the liquid ring vacuum pump inlet thermometer is connected to the liquid ring vacuum pump inlet temperature signal input terminal of the PLC controller, and the signal line of the cooler inlet thermometer is connected to the cooler inlet temperature signal input terminal of the PLC controller.

[0018] As a further improvement of this utility model, the normally open contact of the emergency stop button is connected in series with the emergency stop signal input terminal of the PLC controller, and the coil of the first intermediate relay is connected in series with the audible and visual alarm signal output terminal of the PLC controller.

[0019] Compared with the prior art, the advantages or beneficial effects of the embodiments of this application include at least the following: 1. By using a liquid ring vacuum pump and a Roots vacuum pump in series, the vacuum level and pumping efficiency of the entire system can be improved, and the unit failure rate can be reduced and the service life of the unit can be extended.

[0020] 2. The Roots vacuum pump adopts frequency conversion control, changes the vacuum degree adjustment method, realizes automatic vacuum degree adjustment, improves system stability while reducing energy consumption; and improves the demineralized water replenishment method to realize automatic demineralized water replenishment.

[0021] 3. By installing filters and coolers, the quality of the working fluid in the liquid ring pump is improved, further enhancing the efficiency of the vacuum unit; by optimizing the structure of the gas-liquid separator, the working fluid is ensured to be continuous and the gas-liquid separation effect is improved; the working fluid replenishment method and wastewater discharge method are improved to achieve automatic control of working fluid replenishment and wastewater discharge.

[0022] 4. By optimizing the electrical control system and setting up monitoring instruments, the vacuum unit can be fully automatically controlled, improving the degree of automation, reducing the labor intensity of workers, reducing occupational exposure and safety risks, and at the same time, it can realize fault alarm and safety protection interlock for the unit. Attached Figure Description

[0023] To more clearly illustrate the technical solutions of the embodiments of this utility model, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. The drawings are provided for reference and illustration only and are not intended to limit this utility model. Wherein:

[0024] Figure 1 This is a flowchart of the combined vacuum system for the hydrogen peroxide production line of this utility model;

[0025] Figure 2This is a control system diagram of the combined vacuum system for the hydrogen peroxide production line of this utility model;

[0026] The diagram shows: 1. Liquid ring vacuum pump; 2. Roots vacuum pump; 3. Gas-liquid separator; 4. Filter; 5. Cooler; 6. Exhaust gas collection device; 7. Wastewater treatment plant.

[0027] G1. Vacuum main pipe; G2. Pure water supply pipe; G3. Exhaust pipe; G4. Cooling water inlet pipe; G5. Cooling water outlet pipe; G6. Wastewater discharge pipe;

[0028] V1. Pure water replenishment valve; V2. Wastewater discharge valve;

[0029] P1. Inlet pressure transmitter; F1. Roots vacuum pump cooling water flow meter; T1. Liquid ring vacuum pump inlet thermometer; T2. Cooler inlet thermometer;

[0030] INV1. Inverter; HMI. Touchscreen; PW1. Switching power supply; SD1. Emergency stop button; KM1. Main circuit AC contactor; FR1. Thermal relay;

[0031] KA1. First intermediate relay; KA2. Second intermediate relay; KA3. Third intermediate relay; KA4. Fourth intermediate relay; KA5. Fifth intermediate relay. Detailed Implementation

[0032] In the following description of this utility model, the terms "upper", "lower", "front", "rear", "left", "right", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this utility model and simplifying the description, and do not mean that the device must have a specific orientation.

[0033] To make the technical means, creative features, achieved objectives and effects of this utility model easier to understand, the present utility model will be further described below with reference to specific illustrations. Obviously, the described embodiments are only some embodiments of this utility model, and not all embodiments.

[0034] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

[0035] like Figure 1As shown, the combined vacuum system for the hydrogen peroxide production line of this utility model includes a liquid ring vacuum pump 1 and a Roots vacuum pump 2. The vacuum main pipe G1 is connected to the suction port of the Roots vacuum pump 2, the exhaust port of the Roots vacuum pump 2 is connected to the suction port of the liquid ring vacuum pump 1, the exhaust port of the liquid ring vacuum pump 1 is connected to the air inlet on the top left side of the gas-liquid separator 3, and the exhaust port on the top right side of the gas-liquid separator 3 is connected to the tail gas collection device 6 through the exhaust pipe G3.

[0036] The gas-liquid separator 3 has a vertical partition inside, which extends upward from the bottom of the separator and leaves an overflow space between it and the top wall. The lower left outlet of the gas-liquid separator 3 is connected to the inlet of the filter 4, the outlet of the filter 4 is connected to the hot side inlet of the cooler 5, and the hot side outlet of the cooler 5 is connected to the working fluid inlet of the liquid ring vacuum pump 1. The pure water supply pipe G2 is connected to the water supply port on the left side of the gas-liquid separator 3 through the pure water supply valve V1, and the internal pipe connected to the water supply port extends downward to the lower middle part of the gas-liquid separator 3.

[0037] A liquid ring vacuum pump inlet thermometer T1 is installed on the working fluid inlet pipe of the liquid ring vacuum pump 1, and a cooler inlet thermometer T2 is installed on the hot side inlet pipe of the cooler 5.

[0038] The bottom drain outlet on the right side of the gas-liquid separator 3 is connected to the wastewater discharge pipe G6 via the wastewater discharge valve V2, and the outlet of the wastewater discharge pipe G6 is connected to the wastewater treatment station 7.

[0039] The vent of the liquid ring vacuum pump 1 and the bottom vent on the left side of the gas-liquid separator 3 are also connected to the wastewater discharge pipe G6 to meet the drainage function during maintenance.

[0040] A left level gauge L1 is installed on the left side of the gas-liquid separator 3. The opening and closing of the pure water replenishment valve V1 is controlled by the liquid level measured by the left level gauge L1. When the system is first started, if the measured value of the left level gauge L1 is lower than the set value of the replenishment liquid level, the pure water replenishment valve V1 will be opened to replenish pure water to the left side of the gas-liquid separator 3.

[0041] During normal system operation, the working fluid of the liquid ring vacuum pump 1 enters the top left side of the gas-liquid separator 3 with the airflow, while the gas phase enters the exhaust gas collection device 6 from the exhaust port on the top right side through the exhaust pipe G3. The working fluid falls into the left space of the gas-liquid separator 3 for circulation. A small amount of light components are entrained in the working fluid and overflow from the top of the vertical partition to the right side, where they are discharged through the wastewater discharge valve V2.

[0042] The motor M1 of the liquid ring vacuum pump 1 is also controlled by the liquid level measured by the left liquid level gauge L1. When the measured value of the left liquid level gauge L1 is lower than the low liquid level protection shutdown setting value, the liquid ring vacuum pump 1 stops. When the wastewater discharge valve V2 malfunctions, causing the liquid level in the gas-liquid separator 3 to exceed the top of the vertical partition and reach the high liquid level protection shutdown setting value, the liquid ring vacuum pump 1 also stops.

[0043] A right level gauge L2 is installed on the right side of the gas-liquid separator 3. The opening and closing of the wastewater discharge valve V2 is controlled by the liquid level measured by the right level gauge L2. When the liquid level is higher than the set value for drainage, the wastewater discharge valve V2 opens; when the liquid level is lower than the set value for drainage, the wastewater discharge valve V2 closes.

[0044] The cooling water inlet of the Roots vacuum pump 2 is connected to the cooling water inlet pipe G4, and the cooling water outlet of the Roots vacuum pump 2 is equipped with a Roots vacuum pump cooling water flow meter F1 and connected to the cooling water outlet pipe G5. Cooling water enters the flow channel of the Roots vacuum pump 2 to cool the pump body.

[0045] The cold side inlet of the cooler 5 is also connected to the cooling water inlet pipe G4, and the cold side outlet of the cooler 5 is also connected to the cooling water outlet pipe G5. The working fluid of the liquid ring vacuum pump 1 is cooled down by the cooling water.

[0046] An inlet pressure transmitter P1 is installed at the outlet of the vacuum manifold G1. The motor M2 of the Roots vacuum pump 2 is controlled by a frequency converter. The frequency converter controls the speed of the Roots vacuum pump 2 according to the vacuum signal of the inlet pressure transmitter P1. The pumping volume is adjusted by adjusting the speed of the Roots vacuum pump, thereby achieving automatic adjustment of the vacuum level and reducing the energy consumption of the unit.

[0047] like Figure 2 As shown, the air switch QF1, the main contacts of the main circuit AC contactor KM1, and the thermal relay FR1 are connected in series in the main circuit of the motor M1 of the liquid ring vacuum pump 1. In the control circuit of the motor M1, the fuse FU1, the normally open contact of the second intermediate relay KA2, the coil of the main circuit AC contactor KM1, and the normally closed contact of the thermal relay FR1 are connected in series.

[0048] The motor M2 of the Roots vacuum pump 2 is controlled by the frequency converter INV1. The power supply terminal of the frequency converter INV1 is equipped with an air switch QF2. The normally open contact of the third intermediate relay KA3 is connected in series with the DI1 control terminal of the frequency converter. When the normally open contact of the third intermediate relay KA3 closes, the frequency converter starts. The AO.1 port of the PLC controller is connected to the AI1 control terminal of the frequency converter to regulate the speed of the motor M2.

[0049] The inverter's DO1 control terminal is connected to the PLC controller's DI.4 port, which is the Roots vacuum pump operation feedback port, to feed back the operating signal of motor M2 to the PLC controller. The inverter's DO2 control terminal is connected to the PLC controller's DI.5 port, which is the Roots vacuum pump fault feedback port, to feed back the fault signal of motor M2 to the PLC controller.

[0050] The input terminal of the switching power supply PW1 is connected to the phase voltage through the air switch QF3, and the DC output terminal of the switching power supply PW1 is connected to the power port of the PLC controller.

[0051] The signal line of the inlet pressure transmitter P1 is connected to the AI.1 input port of the PLC controller, which is the inlet pressure signal input terminal. The signal line of the Roots vacuum pump cooling water flow meter F1 is connected to the AI.2 input port of the PLC controller, which is the Roots vacuum pump cooling water flow signal input terminal. The signal line of the liquid ring vacuum pump inlet thermometer T1 is connected to the AI.3 input port of the PLC controller, which is the liquid ring vacuum pump inlet temperature signal input terminal. The signal line of the cooler inlet thermometer T2 is connected to the AI.4 input port of the PLC controller, which is the cooler inlet temperature signal input terminal. The signal line of the left liquid level gauge L1 of the gas-liquid separator 3 is connected to the AI.5 input port of the PLC controller, which is the left liquid level signal input port. The signal line of the right liquid level gauge L2 of the gas-liquid separator 3 is connected to the AI.6 input port of the PLC controller, which is the right liquid level signal input port.

[0052] The normally open contact of the emergency stop button SD1 is connected between V+ and the DI.1 input port of the PLC controller, i.e., the emergency stop signal input terminal. The normally open contact of the main circuit AC contactor KM1 is connected between V+ and the DI.2 input port of the PLC controller, i.e., the liquid ring vacuum pump operation feedback port. The normally open contact of the thermal relay FR1 is connected between V+ and the DI.3 input port of the PLC controller, i.e., the liquid ring vacuum pump fault feedback port. The normally open contact of the valve position switch of the pure water replenishment valve V1 is connected between V+ and the DI.6 input port of the PLC controller, i.e., the pure water replenishment status feedback port. The normally open contact of the valve position switch of the wastewater discharge valve V2 is connected between V+ and the DI.7 input port of the PLC controller, i.e., the wastewater discharge status feedback port.

[0053] The PLC controller's DO.1 output port is the audible and visual alarm signal output terminal, and the coil of the first intermediate relay KA1 is connected between it and V-. The PLC controller's DO.2 output port is the liquid ring vacuum pump control port, and the coil of the second intermediate relay KA2 is connected between it and V-. The PLC controller's DO.3 output port is the Roots vacuum pump control signal output terminal, and the coil of the third intermediate relay KA3 is connected between it and V-. The PLC controller's DO.4 output port is the pure water replenishment control port, and the coil of the fourth intermediate relay KA4 is connected between it and V-. The PLC controller's DO.5 output port is the wastewater discharge control port, and the coil of the fifth intermediate relay KA5 is connected between it and V-.

[0054] The PLC controller's Ethernet port is connected to the communication port of the touch screen HMI. The human-machine interface of the PLC controller and the touch screen HMI is used to monitor, control and alarm interlock the relevant instruments. After setting the relevant parameters, the vacuum unit can be fully automatically controlled without manual intervention. In case of abnormal operating conditions, alarm prompts and safety interlock shutdown will be triggered based on the monitoring data.

[0055] The working principle and operation process of the combined vacuum system of this hydrogen peroxide production line are as follows:

[0056] Before starting the vacuum unit, relevant control parameters are set via the touch screen. Based on the liquid level setting of the gas-liquid separator 3, the working fluid (pure water) is automatically replenished through the pure water replenishment valve V1. After the pure water replenishment of the gas-liquid separator 3 is completed, the coil of the second intermediate relay KA2 is energized, and its normally open contact closes. The coil of the main circuit AC contactor KM1 is energized, and its main contact closes, causing the motor M1 of the liquid ring vacuum pump 1 to start. At the same time, the normally open contact of the main circuit AC contactor KM1 closes, and the motor M1 operation feedback signal is output. After the motor M1 of the liquid ring vacuum pump 1 starts, the system begins to generate a vacuum. The value of the inlet pressure transmitter P1 decreases. The working fluid carrying process gas in the liquid ring pump enters the left side of the gas-liquid separator 3 for gas-liquid separation. After separation, the gas enters the tail gas collection device 6 through the exhaust port, and the working fluid enters the liquid ring vacuum pump for circulation. At the same time, the waste liquid pumped into the vacuum system overflows into the waste liquid isolation area on the right side of the gas-liquid separator 3 for discharge.

[0057] When the vacuum level reaches the set value for starting the Roots vacuum pump, the coil of the third intermediate relay KA3 is energized, its normally open contact closes, the DI1 control terminal of the Roots vacuum pump motor inverter INV1 closes, the Roots vacuum pump motor M2 starts, the inverter's DO1 control terminal closes, and the motor M2's running feedback signal is output. The system forms a PID control loop based on the set vacuum level, the measured value of the inlet pressure transmitter P1, and the motor M2 speed. The motor M2 speed is adjusted through the inverter's AI1 control terminal signal to achieve vacuum control.

[0058] When the left level gauge L1 of the gas-liquid separator 3 is lower than the set value of the water replenishment level, the coil of the fourth intermediate relay KA4 will be energized and will automatically open the pure water replenishment valve V1. At the same time, the normally open contact of the valve position switch of the pure water replenishment valve V1 will close, and the pure water replenishment valve V1 will be open. When the left level gauge L1 of the gas-liquid separator 3 is higher than the set value of the water replenishment level, the coil of the fourth intermediate relay KA4 will be de-energized and will automatically close the pure water replenishment valve V1.

[0059] When the right liquid level gauge L2 of the gas-liquid separator 3 is higher than the set value of the drainage liquid level, the coil of the fifth intermediate relay KA5 will be energized and will automatically open the wastewater discharge valve V2. At the same time, the normally open contact of the valve position switch of the wastewater discharge valve V2 will close, and the open status signal of the wastewater discharge valve V2 will be output. When the right liquid level gauge L2 of the gas-liquid separator 3 is lower than the set value of the drainage liquid level, the coil of the fifth intermediate relay KA5 will be de-energized and will automatically close the wastewater discharge valve V2.

[0060] When the left liquid level gauge L1 of the gas-liquid separator 3 exceeds the high liquid level protection shutdown setting value or the low liquid level protection shutdown setting value, the coil of the second intermediate relay KA2 is de-energized, and the motor M1 of the liquid ring vacuum pump 1 stops.

[0061] When the motor M1 of the liquid ring vacuum pump 1 is overloaded, the normally open contact of the thermal relay FR1 opens, the coil of the main circuit AC contactor KM1 is de-energized, the motor M1 of the liquid ring vacuum pump 1 stops, and at the same time the normally closed contact of the thermal relay FR1 closes, the fault feedback signal of the motor M1 of the liquid ring vacuum pump 1 is output, the coil of the first intermediate relay KA1 is energized, and the audible and visual alarm is output.

[0062] When the motor M2 of the Roots vacuum pump is overloaded, the DO2 control terminal of the frequency converter closes, the fault feedback signal of motor M2 is output, the coil of the audible and visual alarm KA1 is energized, and the audible and visual alarm is output.

[0063] When the flow rate of the Roots vacuum pump cooling water flow meter F1 is too low, the temperature of the liquid ring vacuum pump inlet thermometer T1 is too high, or the temperature of the cooler inlet thermometer T2 is too high, the coil of the audible and visual alarm KA1 will be energized, and the audible and visual alarm will be output.

[0064] In special circumstances where it is necessary to urgently stop the operation of the vacuum unit, press the emergency stop button SD1. The normally open contact of the emergency stop button SD1 will close, de-energizing the coils of the second intermediate relay KA2, the third intermediate relay KA3, the fourth intermediate relay KA4, and the fifth intermediate relay KA5. The motor M1 of the liquid ring vacuum pump 1 will stop, the motor M2 of the Roots vacuum pump will stop, the pure water replenishment valve V1 will close, the wastewater discharge valve V2 will close, and the vacuum unit will stop.

[0065] The above description is merely a preferred embodiment of the present utility model, showing and describing the basic principles, main features, and advantages of the present utility model. It is not intended to limit the scope of patent protection of the present utility model. Those skilled in the art should understand that the present utility model is not limited to the above embodiments. In addition to the above embodiments, the present utility model may have other implementations without departing from the spirit and scope of the present utility model. Various changes and improvements to the present utility model are also possible. All technical solutions formed by equivalent substitutions or equivalent transformations fall within the scope of protection claimed by the present utility model. The scope of protection claimed by the present utility model is defined by the appended claims and their equivalents. Technical features not described in the present utility model can be implemented by or using existing technology, and will not be elaborated here.

Claims

1. A combined vacuum system for a hydrogen peroxide production line, comprising a vacuum manifold (G1), characterized in that: The outlet of the vacuum manifold (G1) is connected to the suction port of the Roots vacuum pump (2), the exhaust port of the Roots vacuum pump (2) is connected in series with the suction port of the liquid ring vacuum pump (1), the exhaust port of the liquid ring vacuum pump (1) is connected to the top left air inlet of the gas-liquid separator (3), and the exhaust port on the top right side of the gas-liquid separator (3) is connected to the tail gas collection device (6); the gas-liquid separator (3) has a vertical partition plate in its inner cavity that divides the tank into left and right chambers, and an overflow channel is left between the partition plate and the top of the tank; The pure water supply pipe (G2) is connected to the left cavity of the gas-liquid separator (3) through the pure water supply valve (V1); the lower outlet of the left cavity of the gas-liquid separator (3) is connected to the hot side inlet of the cooler (5) through the filter (4), and the hot side outlet of the cooler (5) is connected to the working fluid inlet of the liquid ring vacuum pump (1); the bottom drain of the right cavity of the gas-liquid separator (3) is connected to the wastewater discharge pipe (G6) through the wastewater discharge valve (V2).

2. The combined vacuum system for hydrogen peroxide production line according to claim 1, characterized in that: The vent of the liquid ring vacuum pump (1) and the bottom vent on the left side of the gas-liquid separator (3) are also connected to the wastewater discharge pipe (G6), and the outlet of the wastewater discharge pipe (G6) is connected to the wastewater treatment station (7).

3. The combined vacuum system for hydrogen peroxide production line according to claim 1, characterized in that: The outlet of the vacuum manifold (G1) is equipped with an inlet pressure transmitter (P1), and the motor speed of the Roots vacuum pump (2) is controlled by the measured value of the inlet pressure transmitter (P1).

4. The combined vacuum system for a hydrogen peroxide production line according to claim 3, characterized in that: The gas-liquid separator (3) is equipped with a left level gauge (L1) in its left chamber. The pure water replenishment valve (V1) and the liquid ring vacuum pump (1) are both controlled by the level measured by the left level gauge (L1). The gas-liquid separator (3) is equipped with a right level gauge (L2) in its right chamber. The wastewater discharge valve (V2) is controlled by the level measured by the right level gauge (L2).

5. The combined vacuum system for a hydrogen peroxide production line according to claim 4, characterized in that: The cooling water inlet of the casing of the Roots vacuum pump (2) is connected to the cooling water inlet pipe (G4), and the cooling water outlet of the casing of the Roots vacuum pump (2) is equipped with a Roots vacuum pump cooling water flow meter (F1) and connected to the cooling water outlet pipe (G5); the cold side inlet of the cooler (5) is connected to the cooling water inlet pipe (G4), and the cold side outlet of the cooler (5) is also connected to the cooling water outlet pipe (G5).

6. The combined vacuum system for a hydrogen peroxide production line according to claim 5, characterized in that: The main contacts of the main circuit AC contactor (KM1) and the thermal relay (FR1) are connected in series in the main circuit of the liquid ring vacuum pump (1). The control circuit of the liquid ring vacuum pump (1) motor is connected in series with the fuse (FU1), the normally open contact of the second intermediate relay (KA2), the coil of the main circuit AC contactor (KM1), and the normally closed contact of the thermal relay (FR1). The coil of the second intermediate relay (KA2) is connected to the liquid ring vacuum pump control port of the PLC controller. The normally open contact of the main circuit AC contactor (KM1) is connected in series in the liquid ring vacuum pump operation feedback port of the PLC controller, and the normally open contact of the thermal relay (FR1) is connected in series in the liquid ring vacuum pump fault feedback port of the PLC controller.

7. The combined vacuum system for a hydrogen peroxide production line according to claim 6, characterized in that: The motor (M2) of the Roots vacuum pump (2) is controlled by the frequency converter (INV1). The normally open contact of the third intermediate relay (KA3) is connected in series to the DI1 control terminal of the frequency converter. The coil of the third intermediate relay (KA3) is connected in series to the Roots vacuum pump control signal output terminal of the PLC controller. The speed signal output port of the PLC controller is connected to the AI1 control terminal of the frequency converter. The DO1 control terminal of the frequency converter is connected to the running signal input port of the PLC controller. The DO2 control terminal of the frequency converter is connected to the fault signal feedback port of the PLC controller.

8. The combined vacuum system for a hydrogen peroxide production line according to claim 6, characterized in that: The signal line of the left level gauge (L1) is connected to the left level signal input port of the PLC controller. The power supply circuit of the pure water replenishment valve (V1) is connected in series with the normally open contact of the fourth intermediate relay (KA4). The coil of the fourth intermediate relay (KA4) is connected in series with the pure water replenishment control port of the PLC controller. The normally open contact of the valve position switch of the pure water replenishment valve (V1) is connected in series with the pure water replenishment status feedback port of the PLC controller. The signal line of the right liquid level gauge (L2) is connected to the right liquid level input port of the PLC controller. The power supply circuit of the wastewater discharge valve (V2) is connected in series with the normally open contact of the fifth intermediate relay (KA5). The coil of the fifth intermediate relay (KA5) is connected in series with the wastewater discharge control port of the PLC controller. The normally open contact of the valve position switch of the wastewater discharge valve (V2) is connected in series with the wastewater discharge status feedback port of the PLC controller.

9. The combined vacuum system for a hydrogen peroxide production line according to claim 6, characterized in that: The signal line of the inlet pressure transmitter (P1) is connected to the inlet pressure signal input terminal of the PLC controller, the signal line of the Roots vacuum pump cooling water flow meter (F1) is connected to the Roots vacuum pump cooling water flow signal input terminal of the PLC controller, the signal line of the liquid ring vacuum pump inlet thermometer (T1) is connected to the liquid ring vacuum pump inlet temperature signal input terminal of the PLC controller, and the signal line of the cooler inlet thermometer (T2) is connected to the cooler inlet temperature signal input terminal of the PLC controller.

10. The combined vacuum system for a hydrogen peroxide production line according to claim 6, characterized in that: The normally open contact of the emergency stop button (SD1) is connected in series with the emergency stop signal input terminal of the PLC controller, and the coil of the first intermediate relay (KA1) is connected in series with the audible and visual alarm signal output terminal of the PLC controller.

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