Device and method for recycling high-pressure flushing water of galvanizing temper mill

Abstract

A high-pressure flushing water recycling device for a galvanizing temper mill comprises a wastewater collecting tank, a first filter, a second filter, a third filter and a fourth filter, and is characterized in that the first filter is arranged at the upper part of the wastewater collecting tank, and the second filter is arranged beside the first filter; output wastewater of the second filter enters a middle box arranged below, the middle box is provided with a liquid level sensor, the third filter is provided with a first differential pressure transmitter between an inlet pipeline and an outlet pipeline, and the fourth filter is provided with a second differential pressure transmitter between an inlet pipeline and an outlet pipeline. The device and method for recycling the high-pressure flushing water of the galvanizing temper mill have the advantages that graded filtration with the filtration precision from coarse to fine is adopted, the investment is low, the operation cost is low, operation and maintenance are easy, simplicity and high efficiency are achieved, and it is ensured that the recycling index reaches the standard through the arrangement of the conductivity meter and the oil concentration meter.

Description

Technical Field

[0001] The invention relates to high-pressure flushing water in the metallurgical industry, in particular to a high-pressure flushing water recycling device and method for a galvanizing leveler. Background Art

[0002] Against the backdrop of global climate change and increasingly serious domestic environmental problems, high energy consumption and high pollution have become the main factors restricting the development of my country's steel industry. How to transform from a high energy consumption and high emission model to a low energy consumption, low pollution and low emission model is an important issue facing China's steel industry. Reducing the new water consumption per ton of steel in steel enterprises, tapping the potential for recycling and reuse in the steel production process, strengthening the source reduction and comprehensive utilization of wastewater in steel enterprises, and optimizing wastewater treatment processes to achieve standard discharge and reuse are one of the keys to achieving sustainable development of my country's steel enterprises and enhancing their competitiveness.

[0003] In the past, large domestic steel mills did not consider the high-pressure water flushing system when they introduced galvanizing units and leveling machines. In subsequent production practice, obvious zinc sticking problems were found on the roller surface, which eventually led to obvious zinc sticking roller marks on the surface of the galvanized layer of the strip, affecting product quality. The requirements of customers for the surface quality of the strip could not be met. A large steel company made a bold attempt to flush the roller surface with high-pressure water. The water source was desalted water. The galvanizing leveling unit after high-pressure water flushing completely solved the problem of zinc sticking roller marks and ensured the surface quality of the product. Other domestic steel mills followed suit.

[0004] While the high-pressure flushing water system solves the actual problems on site, it also brings new problems. In order to achieve a better flushing effect, the water consumption of high-pressure flushing water needs to be 9m 3 / h, and the wastewater after flushing is directly discharged and transported to the energy medium wastewater station for treatment as cold rolling and leveling wastewater. The application of high-pressure flushing water system increases the consumption of a large amount of new water on the one hand, and increases the amount of wastewater treatment on the other hand, which increases the production cost and the total amount of wastewater discharge, which is contrary to the national energy conservation and emission reduction policy.

[0005] The main problems of existing methods are: (1) The high-pressure flushing water system of the hot-dip galvanizing unit was created and developed to solve the problems of zinc roller marks and strip surface quality. It solved the problems of zinc roller marks and strip surface quality but increased the consumption of new water and the generation of wastewater. It was directly discharged after one use, resulting in serious waste of water resources. (2) Increase the primary investment and water treatment costs of energy-rich wastewater treatment plants; (3) Although domestic water treatment technologies such as conventional filtration technology, microfiltration (MF), ultrafiltration (UF), and reverse osmosis (RO) are quite mature, if the source reduction process adopts a treatment process similar to that used in energy-based wastewater treatment plants, the cost of decentralized treatment will be higher than that of centralized treatment, and its economy and value cannot be reflected.

[0006] Therefore, in the prior art, how to complete the reuse of high-pressure flushing water of the galvanizing leveler has become a technical problem that needs to be solved urgently in this field. Summary of the invention

[0007] The purpose of the present invention is to provide a safe and reliable high-pressure flushing water recycling device for a galvanizing leveler.

[0008] Another object of the present invention is to provide a safe and reliable method for recycling high-pressure flushing water of a galvanizing leveler.

[0009] To achieve the above purpose, the technical solution of the present invention is: A high-pressure flushing water recycling device for a galvanizing leveler, the flushing water recycling device is based on PLC interlocking control, including a wastewater collection tank, a first filter, a second filter, a third filter, and a fourth filter, and is characterized in that: The wastewater collection tank is arranged below the leveling machine, so that the wastewater from the leveling machine is input into the wastewater collection tank through a pump and a valve. A recovery pump is arranged above the wastewater collection tank, and the recovery pump sends the wastewater at the bottom of the wastewater collection tank into the first filter through a wastewater pipeline; an oil skimmer is arranged in the wastewater collection tank; The first filter is arranged on the upper part of the wastewater collection box, the wastewater pipeline is provided with a first flow sensor and a first pressure sensor, the first filter inputs wastewater from the bottom and outputs wastewater from the upper part; The second filter is arranged beside the first filter; the second filter inputs wastewater from the bottom and outputs wastewater from the top, and the output wastewater of the second filter enters the middle box arranged below, the middle box is provided with a liquid level sensor, and the bottom of the middle box inputs wastewater into the third filter through a booster pump and a second pressure sensor; The third filter is provided with a first differential pressure transmitter between the inlet and outlet pipes, and the waste water is input into the fourth filter; The fourth filter is provided with a second differential pressure transmitter between the inlet and outlet pipelines, and the waste water is input into the recovery water tank through the second flow sensor and the valve. The treated water in the recovery water tank is supplied to the leveling machine through the high-pressure water supply pump for high-pressure flushing water reuse.

[0010] The high-pressure flushing water recycling device of the galvanizing leveler of the present invention can also be further implemented by adopting the following technical measures.

[0011] The above-mentioned high-pressure flushing water recycling device for the galvanizing leveler, wherein the first filter is provided with a first backwashing valve.

[0012] The above-mentioned high-pressure flushing water recycling device for the galvanizing leveler, wherein the second filter is provided with a second backwashing valve.

[0013] The above-mentioned high-pressure flushing water recycling device of the galvanizing leveler, wherein a sampling valve is provided in the outlet pipeline of the fourth filter.

[0014] The aforementioned galvanizing leveler high-pressure flushing water recycling device, wherein the recovery water tank is provided with a water replenishment valve.

[0015] A method for recycling high-pressure flushing water of a galvanizing leveler of a high-pressure flushing water recycling device of a galvanizing leveler, characterized by comprising the following steps: a. The wastewater containing zinc powder impurities from the high-pressure washing of the roller surface of the leveling machine enters the leveling machine collection tank, and is selected to enter the wastewater pit or the wastewater collection tank through the automatic valve wastewater direct discharge valve and wastewater recovery valve; b. The wastewater entering the wastewater collection tank is lifted to the first filter for treatment through a recovery pump. A liquid level sensor is installed in the wastewater collection tank, a sewage valve is installed at the bottom of the tank to automatically discharge sewage regularly, and an oil remover is installed to remove oil; a flow sensor and a pressure sensor are installed on the outlet pipe of the recovery pump; c. The outlet water of the first filter enters the second filter with pressure. The second filter is equipped with a pressure differential switch, which automatically backwashes when the set value is reached. The treated outlet water enters the intermediate water tank, which is equipped with a liquid level sensor. A booster pump is set at the outlet of the intermediate water tank to perform PID control with the liquid level sensor to maintain the intermediate water tank at a constant liquid level. A pressure sensor is set at the outlet of the booster pump to monitor the outlet pressure; d. The recovered wastewater is lifted by a booster pump and enters the third filter. A differential pressure transmitter is provided on the inlet and outlet pipes of the third filter to monitor the attenuation of the filter element; e. The outlet water of the third filter enters the fourth filter under pressure. The inlet and outlet pipes of the fourth filter are provided with a differential pressure transmitter to monitor the attenuation of the filter element; f. The outlet pipe of the fourth filter is provided with a sampling valve and a conductivity meter, and is also provided with a discharge valve and a reuse water valve. A flow sensor is provided on the recovery pipeline. When the conductivity meter is within the set value range, the discharge valve is automatically closed and the reuse water valve is automatically opened. When the conductivity meter value exceeds the standard, the discharge valve is automatically opened and the reuse water valve is automatically closed. When the oil concentration meter exceeds the standard, the discharge valve is automatically opened and the reuse water valve is automatically closed, and the oil skimmer is started. When the oil concentration meter is lower than the set value, the discharge valve is automatically closed, the reuse water valve is automatically opened, and the oil skimmer is automatically closed. When the conductivity meter and the oil concentration meter exceed the standard or the recycling system is under maintenance, water is replenished without affecting the normal water supply of the process system. g. After the recycled water enters the desalted water tank, it is transported to the high-pressure spray device in the leveling machine area through a high-pressure flushing water pump for flushing the leveling machine, completing the recycling reuse.

[0016] After adopting the above technical scheme, the high-pressure flushing water recycling device and method of the galvanizing leveler of the present invention have the following advantages: 1. Use graded filtration from coarse to fine filtration accuracy; 2. Low investment, low operating cost, easy operation and maintenance, simple and efficient; 3. Ensure that the reuse indicators meet the standards by setting up conductivity meters and oil concentration meters. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a flow chart of high-pressure flushing water reuse for a galvanizing leveler according to an embodiment of the present invention.

[0018] In the figure: 1-leveling machine collection tray; 2-wastewater direct discharge valve; 3-wastewater recovery valve; 4-wastewater discharge pump; 5-wastewater collection box; 6-discharge valve; 7-wastewater pit; 8-oil skimmer; 9-liquid level sensor 1; 10-recovery pump (frequency conversion pump); 11-flow sensor 1; 12-pressure sensor 1; 13-backwash valve 1; 14-I-level filter device; 15-II-level filter device; 16-backwash valve 2; 17-middle box liquid level sensor; 18-middle Box; 19—boosting pump (frequency conversion pump); 20—pressure sensor 2; 21—III-level filter device; 22—differential pressure transmitter 1; 23—differential pressure transmitter 2; 24—IV-level filter device; 25—sampling valve; 26—discharge valve; 27—flow sensor 2; 28—recycled water valve; 29—recycled water tank; 30—water replenishment valve; 31—liquid level sensor; 32—high-pressure water supply pump; 33—high-pressure water spray device; 34—leveling machine; 35—conductivity meter. DETAILED DESCRIPTION

[0019] The present invention is further described below in conjunction with embodiments and accompanying drawings.

[0020] Example 1 The high-pressure flushing water recycling device of the galvanizing leveler of the present invention comprises a wastewater collection box, a first filter, a second filter, a third filter and a fourth filter.

[0021] Please refer to Figure 1 , Figure 1 This is a flow chart of high-pressure flushing water reuse of a galvanizing leveler according to an embodiment of the present invention. As shown in the figure, the wastewater collection box is arranged below the leveler, so that the wastewater of the leveler is input into the wastewater collection box through a pump and a valve, and a recovery pump is arranged above the wastewater collection box, and the recovery pump sends the wastewater at the bottom of the wastewater collection box into the first filter through a wastewater pipeline; an oil skimmer is arranged in the wastewater collection box; The first filter is arranged on the upper part of the wastewater collection box, the wastewater pipeline is provided with a first flow sensor and a first pressure sensor, the first filter inputs wastewater from the bottom and outputs wastewater from the upper part; The second filter is arranged beside the first filter; the second filter inputs wastewater from the bottom and outputs wastewater from the top, and the output wastewater of the second filter enters the middle box arranged below, the middle box is provided with a liquid level sensor, and the bottom of the middle box inputs wastewater into the third filter through a booster pump and a second pressure sensor; The third filter is provided with a first differential pressure transmitter between the inlet and outlet pipes, and the waste water is input into the fourth filter; The fourth filter is provided with a second differential pressure transmitter between the inlet and outlet pipelines, and the waste water is input into the recovery water tank through the second flow sensor and valve. The treated water in the recovery water tank is supplied to the leveling machine through the high-pressure water supply pump for high-pressure flushing water reuse. The first filter is provided with a first backwash valve. The second filter is provided with a second backwash valve. The outlet pipeline of the fourth filter is provided with a sampling valve. The recovery water tank is provided with a water replenishment valve.

[0022] Example 2 The use method of the high-pressure flushing water recycling device of the galvanizing leveler of the present invention: Step 1: The roller surface is washed with high-pressure water through the high-pressure spray device 33 to remove zinc stuck on the roller surface. The wastewater containing zinc powder and other impurities enters the leveling machine collection tank 1. The wastewater can be selected to enter the wastewater pit 7 or the wastewater collection tank 5 through the automatic valve wastewater direct discharge valve 2 and the wastewater recovery valve 3.

[0023] When the galvanizing unit uses the leveling liquid mode, the system automatically opens the wastewater direct discharge valve 2 and closes the wastewater recovery valve 3. The wastewater directly enters the wastewater pit 7 and is then transported to the energy medium wastewater station for treatment through the wastewater discharge pump 4.

[0024] When the galvanizing unit uses the desalted water spray mode, the system automatically closes the wastewater direct discharge valve 2 and opens the wastewater recovery valve 3. The wastewater enters the wastewater collection tank 5 and is recovered and processed through subsequent processing systems and devices. The galvanizing and leveling unit uses the full desalted water spray mode for more than 98% of the time, that is, the recovery and processing system is put into use within 98% of the operating conditions.

[0025] Step 2: The wastewater entering the wastewater collection box 5 is lifted to the first filter for treatment through the recovery pump (variable frequency pump) 10. A liquid level sensor 9 is set in the wastewater collection box 5. A sewage valve 6 is set at the bottom of the box to automatically discharge sewage regularly, and an oil remover 8 is set to remove oil. A flow sensor 11 and a pressure sensor 12 are set on the outlet pipeline of the recovery pump (variable frequency pump) (10) to monitor the flow of the first filter and the resistance change of the filter element. The first-level filter device 14 has a pressure difference detection device. When the set value is reached, the flushing valve 13 is automatically opened for automatic backwashing, and the intercepted impurities are flushed into the wastewater ditch.

[0026] Step 3: The outlet water of the first filter enters the second filter with pressure. The II-level filter device is equipped with a pressure differential switch, which automatically backwashes when the set value is reached. The filtering accuracy of the II-level filter device 15 is higher than that of the I-level filter device 14. The treated outlet water enters the intermediate water tank 18. A liquid level sensor (17) is arranged in the intermediate water tank. A booster pump (variable frequency pump) 19 is arranged at the outlet of the intermediate water tank to perform PID control with the liquid level sensor 17 to maintain the intermediate water tank at a constant liquid level. A pressure sensor 220 is arranged at the outlet of the booster pump (variable frequency pump) 19 to monitor the outlet pressure.

[0027] Step 4: The recovered wastewater is lifted by the booster pump (variable frequency pump) 19 and enters the Class III filtration device 21. A differential pressure transmitter 22 is provided on its inlet and outlet pipelines to monitor the attenuation of the filter element. When the pressure difference reaches a certain value, the filter element may be replaced according to the system operation.

[0028] Step 5: The outlet water of the III-level filter device 21 enters the IV-level filter device 24 with pressure. The differential pressure transmitter 23 is installed on the inlet and outlet pipelines to monitor the attenuation of the filter element. However, when the pressure difference reaches a certain value, the filter element can be replaced according to the system operation.

[0029] Step 6: The outlet pipe of the IV-level filter device 24 is provided with a sampling valve 25 and a conductivity meter 35, and is also provided with a discharge valve 26 and a reuse water valve 28. A flow sensor 227 is provided on the recovery pipeline. The recovered water passing through 27 and 28 enters the recovery water tank (desalt water tank) 29 for recycling. 29 is provided with an oil concentration meter 36, a liquid level sensor 31 and a desalted water replenishment valve 29. When the conductivity meter 35 is within the set value range, the discharge valve 26 is automatically closed and the reuse water valve 28 is automatically opened. When the value of the conductivity meter 35 exceeds the standard, the discharge valve 26 automatically opens and the reuse water valve 28 automatically closes. When the oil concentration meter 36 exceeds the standard, the discharge valve 26 automatically opens, the reuse water valve 28 automatically closes, and the oil skimmer 8 is started. When the oil concentration meter 36 is lower than the set value, the discharge valve 26 automatically closes, the reuse water valve 28 automatically opens, and the oil skimmer 8 is automatically shut down. When the conductivity meter 35 and the oil concentration meter 36 exceed the standard or the recycling system is under maintenance, water can be replenished through 29 without affecting the normal water supply of the process system.

[0030] Step 7: After the recovered water enters the desalted water tank 29, it is transported to the high-pressure spray device 33 in the leveling machine area through the high-pressure flushing water pump 32 for use in flushing the leveling machine 35, completing the recycling reuse.

[0031] The present invention has substantial characteristics and significant technical progress. The high-pressure flushing water recycling device and method of the galvanized leveler of the present invention is an integrated device automatically controlled by PLC, including a wastewater lifting pump, a backwashing filter, a bag filter, a precision filter, a wastewater lifting pump, a filter booster pump, a water tank, a pressure sensor, a flow sensor, a liquid level sensor, a conductivity meter and an oil concentration meter and an electrical operation control box. The high-pressure flushing water recycling device and method of the galvanized leveler of the present invention, through PLC interlocking control, pioneeringly treats and reuses the high-pressure flushing water of the galvanized leveler, creatively develops a set of high-pressure flushing water recycling technology that not only achieves water saving and emission reduction but also guarantees the unit's own needs. Combined with the characteristics of wastewater quality, a graded filtration scheme with filtration accuracy from coarse to fine is adopted, which has the characteristics of low investment, low operating cost, easy operation and maintenance, simple and efficient.

[0032] The high-pressure flushing water recycling device and method of the galvanizing leveler of the present invention reduces the consumption of new water and can reduce production costs; the treated recycled water can meet the requirements of high-pressure flushing of the galvanizing unit. The conductivity meter and the oil concentration meter are set to ensure that the recycling index meets the standard, and the normal production of the galvanizing unit is not affected when the index exceeds the standard or in a fault state. The high-pressure flushing water recycling device and method of the galvanizing leveler of the present invention adopts a variable frequency pump, and the variable frequency pump is controlled to adapt to the water volume change of the unit, ensuring continuous operation and reducing energy consumption. .

[0033] The above embodiments are only for the purpose of illustrating the present invention, but not for limiting the present invention. A person skilled in the art may make various changes or modifications without departing from the spirit and scope of the present invention. Therefore, all equivalent technical solutions should also belong to the scope of the present invention and should be defined by the claims.

Claims

1. A high-pressure flushing water recycling device for a galvanizing leveler, the flushing water recycling device is based on PLC interlocking control, including a wastewater collection tank, a first filter, a second filter, a third filter, and a fourth filter, characterized in that: The wastewater collection tank is arranged below the leveling machine, so that the wastewater from the leveling machine is input into the wastewater collection tank through a pump and a valve. A recovery pump is arranged above the wastewater collection tank, and the recovery pump sends the wastewater at the bottom of the wastewater collection tank into the first filter through a wastewater pipeline; an oil skimmer is arranged in the wastewater collection tank; The first filter is arranged on the upper part of the wastewater collection box, the wastewater pipeline is provided with a first flow sensor and a first pressure sensor, the first filter inputs wastewater from the bottom and outputs wastewater from the upper part; The second filter is arranged beside the first filter, the second filter inputs wastewater from the bottom and outputs wastewater from the top, the output wastewater of the second filter enters the middle box arranged below, the middle box is provided with a liquid level sensor, and the bottom of the middle box inputs wastewater into the third filter through a booster pump and a second pressure sensor; The third filter is provided with a first differential pressure transmitter between the inlet and outlet pipes, and the waste water is input into the fourth filter; The fourth filter is provided with a second differential pressure transmitter between the inlet and outlet pipelines, and the waste water is input into the recovery water tank through the second flow sensor and the valve. The treated water in the recovery water tank is supplied to the leveling machine through the high-pressure water supply pump for high-pressure flushing water reuse.

2. The high-pressure flushing water recycling device for a galvanizing and leveling machine according to claim 1, characterized in that: The first filter is provided with a first backwash valve.

3. The high-pressure flushing water recycling device for a galvanizing and leveling machine according to claim 1, characterized in that: The second filter is provided with a second backwash valve.

4. The high-pressure flushing water recycling device for a galvanizing and leveling machine according to claim 1, characterized in that: A sampling valve is provided in the outlet pipeline of the fourth filter.

5. The high-pressure flushing water recycling device for a galvanizing and leveling machine according to claim 1, characterized in that: The recovered water tank is provided with a water replenishment valve.

6. A method for recycling high-pressure flushing water of a galvanizing leveler according to claim 1, characterized in that The following steps are involved: a. The wastewater containing zinc powder impurities from the high-pressure washing of the roller surface of the leveling machine enters the leveling machine collection tank (1), and is selected to enter the wastewater pit (7) or the wastewater collection tank through the automatic valve wastewater direct discharge valve (2) and the wastewater recovery valve (3); b. The wastewater entering the wastewater collection tank (5) is lifted to the first filter for treatment by a recovery pump (10). A liquid level sensor (9) is provided in the wastewater collection tank (5). A sewage valve (6) is provided at the bottom of the tank to automatically discharge sewage at regular intervals. An oil remover (8) is also provided to remove oil. A flow sensor (11) and a pressure sensor (12) are provided on the outlet pipeline of the recovery pump. c. The outlet water of the first filter enters the second filter under pressure. The second filter is equipped with a pressure differential switch, and automatically backwashes when the set value is reached. The treated outlet water enters the intermediate water tank (18). A liquid level sensor (17) is provided in the intermediate water tank. A booster pump (19) is provided at the outlet of the intermediate water tank to perform PID control with the liquid level sensor (17) to maintain the intermediate water tank at a constant liquid level. A pressure sensor is provided at the outlet of the booster pump (19) to monitor the outlet pressure; d. The recovered wastewater is lifted by a booster pump (19) and enters a third filter. A differential pressure transmitter (22) is provided on the inlet and outlet pipes of the third filter to monitor the attenuation of the filter element; e. The outlet water of the third filter enters the fourth filter under pressure. A differential pressure transmitter (23) is provided on the inlet and outlet pipes of the fourth filter to monitor the attenuation of the filter element; f. A sampling valve (25) and a conductivity meter (35) are provided on the outlet pipe of the fourth filter, and a discharge valve (26) and a reuse water valve (28) are also provided. A flow sensor (27) is provided on the recovery pipe. When the conductivity meter (35) is within the set value range, the discharge valve (26) is automatically closed and the reuse water valve (28) is automatically opened. When the value of the conductivity meter (35) exceeds the standard, the discharge valve (26) is automatically opened and the reuse water valve (28) is automatically closed. When the oil concentration meter (36) exceeds the standard, the discharge valve (26) is automatically opened and the reuse water valve (28) is automatically closed, and the oil skimmer (8) is started. When the oil concentration meter (36) is lower than the set value, the discharge valve (26) is automatically closed and the reuse water valve (28) is automatically opened, and the oil skimmer (8) is automatically closed. When the conductivity meter (35) and the oil concentration meter (36) exceed the standard or the recycling system is in the maintenance state, water is replenished through (29) without affecting the normal water supply of the process system. g. After the recycled water enters the desalted water tank (29), it is transported to the high-pressure spray device (33) in the leveling machine area through the high-pressure flushing water pump (32) to be used for flushing the leveling machine (35), thus completing the recycling reuse.

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