High-viscosity waste acid filtration treatment methods and backwashing methods

Abstract

This invention relates to a method for filtering and backwashing high-viscosity waste acid. The method is as follows: The waste phosphoric acid solution in the raw solution collection tank is brought to the set value by the level sensor; the waste acid solution in the acid-producing collection tank is pumped into the treatment equipment via a pneumatic pump. When the waste acid solution reaches the first or second set value of the level sensor, the pneumatic pump, the first inlet valve, and the second inlet valve are closed or opened; the aeration system, metering pump, the first electric valve, and the automatic level control valve in the treatment equipment are opened, and the waste acid solution in the treatment equipment flows through the membrane tank to the acid-producing collection tank; after the metering pump runs for a set time, it closes the automatic level control valve and the first electric valve; the first and second valves and the pneumatic pump are opened, and the concentrated liquid in the treatment equipment is discharged to the raw solution collection tank; (5) the magnetic pump, the second and third electric valves are opened, and the liquid flows back into the membrane tank to clean membrane impurities; (6) steps (5) and (6) are repeated. When the waste acid solution in the raw solution collection tank is lower than the set value of the level sensor or the acid solution in the acid-producing collection tank is higher than the set value of the level sensor, the equipment stops.

Description

Technical Field

[0001] This invention belongs to the field of waste acid treatment technology, and specifically relates to a method for filtering and treating high-viscosity waste acid and a backwashing method. Background Technology

[0002] Traditional anodizing and metal processing involve the use of large amounts of strong acids such as phosphoric acid, nitric acid, and sulfuric acid for chemical polishing of workpieces. However, during chemical polishing, as the concentration of dissolved metal increases, the concentration of free acid decreases accordingly, causing the workpieces to fail to meet processing standards. Although adding new inorganic acid to the chemical polishing solution can solve the problem of insufficient acidity, when the metal concentration increases to a certain level, these chemical polishing acids must be replaced, resulting in a large amount of waste acid. Direct discharge of this waste acid would cause significant environmental pollution; therefore, it is necessary to treat this waste acid before discharge.

[0003] Traditional phosphoric acid recovery methods, such as calcium salt precipitation, suffer from high lime consumption, large sludge production, and high processing costs. This has led to the development of a waste acid recovery technology. This technology requires pretreatment of the waste acid to remove impurities and organic matter, followed by removal of metal ions and evaporation, thereby achieving resource recovery and reuse while reducing environmental pollution. However, during the pretreatment process, the chemical waste liquid contains some high-viscosity substances. These substances easily adhere to the surface of filtration equipment, causing blockages that are difficult to clean and may even render the filtration equipment unusable. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide a solution to the problems of membrane fouling and difficulty in cleaning that occur when traditional membrane equipment encounters high-viscosity waste acid. The treated waste phosphoric acid can be recycled after removing metal ions such as aluminum, reducing the pollution of these waste acids to the environment. This invention meets the requirements of enterprises for high-viscosity waste acid filtration and backwashing methods.

[0005] The technical solution of this invention is the high-viscosity waste acid filtration treatment method, which is characterized by including a high-viscosity waste acid filtration system. The high-viscosity waste acid filtration system includes a raw material collection tank connected to a treatment device via a first inlet valve, a pneumatic pump, and a second inlet valve arranged sequentially on a pipeline. The membrane tank of the treatment device is connected to an acid-producing collection tank via a first electric valve, a metering pump, a flow meter, a pressure sensor, and an automatic level control valve arranged sequentially on a pipeline. The acid-producing collection tank is connected to the membrane tank of the treatment device via a second electric valve, a magnetic pump, a second flow meter, a pressure gauge, and a third electric valve. A controller controls the opening of the first electric valve and the automatic level control valve, causing the acid generated in the membrane tank to flow into the acid-producing collection tank. The high-viscosity waste acid filtration treatment method includes the following steps:

[0006] (1) Collect the waste phosphoric acid solution into the original solution collection tank. When the waste acid solution reaches the set value of the first liquid level sensor, the equipment starts to run.

[0007] (2) Under the action of the pneumatic pump, the waste acid liquid in the acid collection tank enters the treatment equipment through the pipeline. When the waste acid liquid in the treatment equipment reaches the set value of the second liquid level sensor, the pneumatic pump is started and the first liquid inlet valve and the second liquid inlet valve are closed.

[0008] (3) When the waste acid liquid in the treatment equipment reaches another set value of the second liquid level sensor, the pneumatic pump, the first electric valve and the second electric valve are opened;

[0009] (4) The aeration system inside the treatment equipment is turned on, causing the liquid inside the treatment equipment to circulate; at this time, the metering pump, the first electric valve, and the automatic liquid level control valve are turned on. Under the action of the metering pump, the waste acid liquid inside the treatment equipment flows out from the membrane tank after being filtered by the membrane tank and flows to the acid production collection tank.

[0010] (5) When the metering pump runs for the set time, the controller commands the metering pump, the automatic liquid level control valve and the first electric valve to close; after closing, the controller commands the first valve, the second valve and the pneumatic pump to open, so as to discharge the concentrated liquid in the treatment equipment to the raw liquid collection tank.

[0011] (6) When the magnetic pump, the second electric valve and the third electric valve are opened, the acid in the acid collection tank is transported to the inside of the membrane fiber in the membrane box by the magnetic pump. Under the action of aeration, the impurities attached to the membrane surface are cleaned from the inside out.

[0012] (7) Steps (5) and (6) are repeated until the waste acid in the raw liquid collection tank is lower than the set value of the first liquid level sensor or the acid in the acid production collection tank is higher than the set value of the third liquid level sensor. At this point, the controller instructs the equipment to stop operating.

[0013] Preferably, the controller activates the metering pump during a set first time period by controlling the time. Simultaneously, the first electric valve and the automatic level control valve on the pipeline connecting the metering pump to the membrane tank and the acid collection tank open, allowing the acid generated in the membrane tank to flow into the acid collection tank. After the set first time period is completed, the metering pump, the automatic level control valve, and the first electric valve stop operating and close respectively under the control of the controller. Subsequently, the controller begins operating for a set second time period. During this time, the magnetic pump starts running, and the third electric valve and the second electric valve on the pipeline connecting the membrane tank and the acid collection tank open, allowing the acid in the acid collection tank to flow through the pipeline into the membrane tank under the action of the magnetic pump.

[0014] Preferably: the raw liquid collection tank is equipped with a first liquid level sensor to monitor the amount of waste acid entering the raw liquid collection tank; a second liquid level sensor is installed in the treatment equipment to detect the amount of waste acid in the treatment equipment; a third liquid level sensor is installed in the acid-producing collection tank to monitor the amount of acid-producing liquid in the acid-producing collection tank; the bottom of the treatment equipment is provided with an outlet connected to the raw liquid collection tank; the concentrated liquid remaining after filtration in the treatment equipment is pumped from the bottom into the raw liquid collection tank by a pneumatic pump through the opening of the first valve; a discharge port is provided at the bottom of the raw liquid collection tank to discharge the concentrated liquid in the raw liquid collection tank after a set time.

[0015] Another technical solution of the present invention is a backwashing method for the high-viscosity waste acid filtration system, characterized in that it includes a high-viscosity waste acid filtration system. The high-viscosity waste acid filtration system includes a raw material collection tank connected to a treatment device via a first inlet valve, a pneumatic pump, and a second inlet valve arranged sequentially on a pipeline. The membrane tank of the treatment device is connected to an acid-producing collection tank via a first electric valve, a metering pump, a flow meter, a pressure sensor, and an automatic level control valve arranged sequentially on a pipeline. The acid-producing collection tank is connected to the membrane tank of the treatment device via a second electric valve, a magnetic pump, a second flow meter, a pressure gauge, and a third electric valve. A controller controls the opening of the first electric valve and the automatic level control valve, causing the acid generated in the membrane tank to flow into the acid-producing collection tank. The backwashing method includes the following steps:

[0016] (1) When the backwashing process is started, the first valve, the second valve and the pneumatic pump are opened to discharge the concentrated liquid in the treatment equipment to the raw liquid collection tank.

[0017] (2) When the magnetic pump, the second electric valve and the third electric valve are opened, the acid in the acid collection tank is transported to the membrane fiber in the membrane box by the magnetic pump.

[0018] (3) When the set time period is reached, the metering pump, automatic level control valve, and first electric valve will stop running and close respectively under the control of the controller;

[0019] (4) When the controller starts running for the second set period, the magnetic pump starts running. The third and second electric valves on the pipeline connecting the magnetic pump to the membrane tank and the acid collection tank open. The acid in the acid collection tank is transported to the inside of the membrane fibers in the membrane tank by the magnetic pump. Under the action of aeration, the impurities attached to the membrane surface are cleaned from the inside out.

[0020] Preferably: the raw liquid collection tank is equipped with a first liquid level sensor to monitor the amount of waste acid entering the raw liquid collection tank; a second liquid level sensor is installed in the treatment equipment to detect the amount of waste acid in the treatment equipment; a third liquid level sensor is installed in the acid production collection tank to monitor the amount of acid production in the acid production collection tank; the bottom of the treatment equipment is provided with an outlet connected to the raw liquid collection tank; the concentrated liquid remaining after filtration in the treatment equipment is pumped from the bottom into the raw liquid collection tank by a pneumatic pump through the opening of the first valve; a discharge port is provided at the bottom of the raw liquid collection tank to discharge the concentrated liquid in the raw liquid collection tank after a set time.

[0021] Preferably, the controller activates the metering pump during a set first time period by controlling the time. Simultaneously, the first electric valve and the automatic level control valve on the pipeline connecting the metering pump to the membrane tank and the acid collection tank open, allowing the acid generated in the membrane tank to flow into the acid collection tank. After the set first time period is completed, the metering pump, the automatic level control valve, and the first electric valve stop operating and close respectively under the control of the controller. Subsequently, the controller begins operating for a set second time period. During this time, the magnetic pump starts running, and the third electric valve and the second electric valve on the pipeline connecting the membrane tank and the acid collection tank open, allowing the acid in the acid collection tank to flow through the pipeline into the membrane tank under the action of the magnetic pump.

[0022] Compared with the prior art, the beneficial effects of the present invention are as follows: (1) The present invention uses an organic membrane material with a hydrophobic surface and uniform pore size, which makes it difficult for highly viscous substances contained in waste acid to adhere to the surface of the membrane.

[0023] (2) By adding an aeration system, the present invention keeps the water sample in the treatment equipment in a rolling state, so that high viscosity substances cannot stay on the membrane for a long time, thus making the membrane more difficult to be blocked.

[0024] (3) Each electric valve in this invention is controlled by a PLC, which has a high degree of automation, reduces the cost of manual control, and is conducive to the promotion and application of the device. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the high-viscosity waste acid filtration system of the present invention.

[0026] Explanation of key component symbols:

[0027] Original liquid collection tank 1 First liquid level sensor 11 Processing equipment 2 Pneumatic pump 21 First inlet valve 211 Second inlet valve 212 First valve 213 Second valve 214 Membrane box 22 Second liquid level sensor 24 Controller 3 Metering pump 31 First flow meter 311 Pressure sensor 312 Automatic level control valve 313 First electric valve 314 Magnetic pump 32 Second electric valve 321 Second flow meter 322 Pressure gauge 323 Third electric valve 324 Acid collection tank 4 Third liquid level sensor 41 Detailed Implementation

[0028] The present invention will now be described in further detail with reference to the accompanying drawings:

[0029] Please see Figure 1As shown, the high-viscosity waste acid filtration system includes a filtration device, a backwashing device, and a circulation control device.

[0030] The filtration device includes a raw liquid collection tank 1, a pneumatic pump 21, and a processing device 2. The raw liquid collection tank 1 contains waste acid liquid discharged after processing. The raw liquid collection tank 1 is equipped with a first liquid level sensor 11 to monitor the amount of waste acid liquid entering the raw liquid collection tank 1. The pneumatic pump 21 is connected to the raw liquid collection tank 1 through a pipeline, and a first inlet valve 211 is provided on the connected pipeline. The pneumatic pump 21 is connected to the processing device 2 through a pipeline, and a second inlet valve 212 is provided on the connected pipeline. A second liquid level sensor 24 is provided in the processing device to detect the amount of waste acid liquid in the processing device. When the liquid level in the processing device 2 is lower than a set height, the first inlet valve 211 and the second inlet valve 212 open, and the pneumatic pump 21 starts to automatically replenish the liquid. When the liquid level in the processing device 2 is higher than the set height, the pneumatic pump 21 shuts down. The membrane tank inside the processing device 2 is connected to the metering pump 31 through a pipeline, and a first electric valve 314 is installed on the pipeline. The metering pump 31 is connected to the acid production collection tank 4 through a pipeline, and a flow meter 311, a pressure sensor 312 and an automatic liquid level control valve 313 are installed on the pipeline. A third liquid level sensor 41 is installed inside the acid production collection tank 4 to monitor the amount of acid produced liquid in the acid production collection tank 4.

[0031] The processing device 2 has an outlet at its bottom, which connects to the raw liquid collection tank 1. A first valve 213 and a second valve 214 are installed on the pipeline connecting the processing device 2 and the raw liquid collection tank 1. The concentrated liquid remaining after filtration in the processing device 2 can be drawn from the bottom into the raw liquid collection tank 1 by opening the first valve 213 under the action of the pneumatic pump 21. A discharge port is provided at the bottom of the raw liquid collection tank 1, allowing the concentrated liquid in the tank to be discharged after a period of time.

[0032] The backwashing device includes an acid-producing collection tank 4, a pneumatic pump 21, and a magnetic pump 32. The acid-producing collection tank 4 and the magnetic pump 32 are connected by a pipeline, and a second electric valve 321 is installed on the connecting pipeline. The magnetic pump 32 is connected to a membrane tank inside the treatment equipment 2 by a pipeline, and a flow meter 322 and a pressure gauge 323 are installed on the connecting pipeline. The pneumatic pump 21 is connected to the treatment equipment 2 by a pipeline, and a first valve 213 is installed on the connecting pipeline. The pneumatic pump 21 is also connected to the original liquid collection tank 1 by a pipeline. A first valve 211 is installed on the connected pipeline; when the backwashing device is turned on, the first valve 213, the second valve 214 and the pneumatic pump 21 are turned on, and the concentrated liquid in the treatment equipment 2 is discharged to the raw liquid collection tank 1; then the magnetic pump 32, the second electric valve 321 and the third electric valve 324 are turned on, and the acid in the acid collection tank 4 is transported to the inside of the membrane fiber in the membrane box by the magnetic pump 32. Under the action of aeration, the impurities attached to the membrane surface are cleaned from the inside to the outside, thereby achieving the purpose of cleaning.

[0033] The circulation control device includes the controller 3, the metering pump 31, and the magnetic pump 32. The controller controls the time via PLC programming. During a set first time period, the metering pump 31 is turned on, and the first electric valve 314 and the automatic level control valve 313 on the pipeline connected to the membrane tank 22 and the acid collection tank 4 are also turned on, allowing the acid produced in the membrane tank 22 to flow into the acid collection tank 4. After the set first time period is completed, the metering pump 31, the automatic level control valve 313, and the first electric valve 314 are turned off and closed respectively under the control of the controller 2. Subsequently, the controller 2 will start running a set second time period. During this time, the magnetic pump 32 starts running, and the third electric valve 324 and the second electric valve 321 on the pipeline connected to the membrane tank 22 and the acid collection tank 4 are also turned on, allowing the acid in the acid collection tank 4 to flow into the membrane tank 22 through the pipeline under the action of the magnetic pump 32.

[0034] The working process of this invention embodiment is as follows: The waste acid liquid in this embodiment is waste phosphoric acid. The waste phosphoric acid liquid discharged by the enterprise is collected in the raw liquid collection tank 1. When the waste acid liquid reaches the set value of the first liquid level sensor 11, the equipment starts to operate. Under the action of the pneumatic pump 21, the waste acid liquid in the acid collection tank 1 enters the treatment equipment 2 through the pipeline. When the waste acid liquid in the treatment equipment 2 reaches the set value of the second liquid level sensor 24, the pneumatic pump 21, the first liquid inlet valve 211, and the second liquid inlet valve 212 are closed. When the waste acid liquid in the treatment equipment 2 reaches another set value of the second liquid level sensor 24, the pneumatic pump 21, the first liquid inlet valve 211, and the second liquid inlet valve 212 are opened. The aeration system 23 in the treatment equipment 2 is turned on, causing the liquid in the treatment equipment 2 to circulate. At this time, metering pump 31, first electric valve 314, and automatic level control valve 313 are opened. Under the action of metering pump 31, the waste acid in treatment equipment 2 is filtered through membrane tank 22 and flows out of membrane tank 22, flowing to acid collection tank 4. After metering pump 31 has run for the set time, metering pump 31, automatic level control valve 313, and first electric valve 314 are closed. After closing, first valve 213, second valve 214, and pneumatic pump 21 are opened to discharge the concentrated liquid in treatment equipment 2 to raw liquid collection tank 1. Then, magnetic pump 32, second electric valve 321, and third electric valve 324 are opened, and the acid in acid collection tank 4 is backflowed into membrane tank 22 under the action of magnetic pump 32 to clean the impurities attached to the membrane surface. These two processes are repeated until the waste acid in raw liquid collection tank 1 is lower than the set value of level sensor 11 or the acid in acid collection tank 4 is higher than the set value of level sensor 41, at which point the equipment stops operating.

[0035] The above description is only a preferred embodiment of the present invention. All equivalent changes and modifications made within the scope of the claims of the present invention should be covered by the claims of the present invention.

Claims

1. A method for filtering and treating high-viscosity waste acid, characterized in that, Including high-viscosity waste acid filtration systems; The high-viscosity waste acid filtration system includes: The raw liquid collection tank is equipped with a first liquid level sensor; The treatment equipment includes a membrane tank, an aeration system, and a second liquid level sensor. The aeration system is used to circulate the liquid inside the treatment equipment to prevent the adhesion of high-viscosity substances. The acid collection tank is equipped with a third liquid level sensor. The raw liquid collection tank is connected to the processing equipment through a first pipeline, and a first liquid inlet valve, a pneumatic pump and a second liquid inlet valve are sequentially arranged along the fluid direction on the first pipeline. The membrane box of the treatment equipment is connected to the acid collection tank through a second pipeline. The second pipeline is provided with a first electric valve, a metering pump, a flow meter, a pressure sensor and an automatic liquid level control valve in sequence along the fluid direction. The acid collection tank is connected to the membrane box of the treatment equipment through a third pipeline. The third pipeline is provided with a second electric valve, a magnetic pump, a second flow meter, a pressure gauge and a third electric valve in sequence along the fluid direction. The bottom of the processing equipment is provided with a concentrated liquid outlet connected to the raw liquid collection tank via a fourth pipeline. The fourth pipeline is provided with a first valve, the pneumatic pump and a second valve in sequence along the fluid direction. And the controller; The high-viscosity waste acid filtration treatment method includes the following steps: (1) Collect the high-viscosity waste phosphoric acid solution into the original solution collection tank. When the first liquid level sensor detects that the liquid level has reached the first set value, the controller starts the system operation. (2) The controller opens the first inlet valve, the second inlet valve and the pneumatic pump to pump the waste acid liquid in the raw liquid collection tank into the treatment equipment; when the second liquid level sensor detects that the liquid level in the treatment equipment reaches the second set value, the controller closes the pneumatic pump, the first inlet valve and the second inlet valve. (3) The controller starts the aeration system in the treatment equipment and simultaneously starts the first electric valve, metering pump and automatic liquid level control valve; under the action of the metering pump, the waste acid liquid in the treatment equipment is filtered through the membrane tank and the filtered acid liquid flows into the acid production collection tank. (4) When the metering pump has been running for a first preset time, the controller shuts down the metering pump, the first electric valve, and the automatic liquid level control valve; (5) The controller opens the first valve, the second valve and the pneumatic pump to discharge the concentrated high-viscosity liquid in the processing equipment back to the original liquid collection tank; (6) The controller opens the second electric valve, the magnetic pump and the third electric valve, and the acid in the acid collection tank is transported to the membrane fiber inside the membrane box by the magnetic pump. At the same time, the aeration system continues to work, using the acid backflow from the inside of the membrane fiber and the aeration disturbance to clean the impurities attached to the membrane surface. (7) Repeat steps (5) and (6) until the first liquid level sensor detects that the liquid level in the raw liquid collection tank is lower than the first set value, or the third liquid level sensor detects that the liquid level in the acid production collection tank is higher than the third set value, at which point the controller controls the entire system to stop running.

2. The method for filtration and treatment of high-viscosity waste acid according to claim 1, characterized in that, The bottom of the raw liquid collection tank is equipped with a discharge port for periodically discharging the accumulated high-viscosity concentrate.

3. A backwashing method for a high-viscosity waste acid filtration system, characterized in that, Applications include high-viscosity waste acid filtration systems; The high-viscosity waste acid filtration system includes: The raw liquid collection tank is equipped with a first liquid level sensor; The treatment equipment includes a membrane tank, an aeration system, and a second liquid level sensor. The aeration system is used to circulate the liquid inside the treatment equipment to prevent the adhesion of high-viscosity substances. The acid collection tank is equipped with a third liquid level sensor. The raw liquid collection tank is connected to the processing equipment through a first pipeline, and a first liquid inlet valve, a pneumatic pump and a second liquid inlet valve are sequentially arranged along the fluid direction on the first pipeline. The membrane box of the treatment equipment is connected to the acid collection tank through a second pipeline. The second pipeline is provided with a first electric valve, a metering pump, a flow meter, a pressure sensor and an automatic liquid level control valve in sequence along the fluid direction. The acid collection tank is connected to the membrane box of the treatment equipment through a third pipeline. The third pipeline is provided with a second electric valve, a magnetic pump, a second flow meter, a pressure gauge and a third electric valve in sequence along the fluid direction. The bottom of the processing equipment is provided with a concentrated liquid outlet connected to the raw liquid collection tank via a fourth pipeline. The fourth pipeline is provided with a first valve, the pneumatic pump and a second valve in sequence along the fluid direction. And the controller; The backwashing method includes the following steps: (1) When the backwashing procedure is triggered, the controller opens the first valve, the second valve and the pneumatic pump to discharge the concentrated liquid in the treatment equipment to the raw liquid collection tank. (2) The controller opens the second electric valve, the magnetic pump and the third electric valve, and the acid in the acid collection tank is transported to the membrane fiber in the membrane box by the magnetic pump; (3) While step (2) is being performed, the aeration system in the treatment equipment remains on, using acid to backflush from the inside of the membrane fibers and combined with the disturbance generated by aeration to clean the impurities attached to the membrane surface from the inside out. (4) After the backwashing operation continues for a second preset time, the controller shuts off the magnetic pump, the second electric valve and the third electric valve to complete one backwashing cycle.

4. The backwashing method for the high-viscosity waste acid filtration system according to claim 3, characterized in that, Before the backwashing process begins, the controller first closes the first inlet valve, the second inlet valve, the first electric valve, and the automatic level control valve to isolate the filtration process.

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