Membrane switching multi-section type membrane stack filtering method

Abstract

The invention provides a membrane switching multi-section type membrane stack filtering method, which is characterized in that the water inlet direction is switched through an electromagnetic valve for controlling the water inlet direction on a multi-section type membrane stack device, and the problem of unbalanced membrane performance of the multi-section type membrane stack device is improved, so that the utilization rate of each section of membrane component is improved, and the service life of each section of membrane component is ensured. Meanwhile, operation of the device can be controlled through an automatic control system, and operation management is convenient. In addition, the multi-section membrane stack device improves the utilization rate of concentrated water and realizes full utilization of water resources. In conclusion, the membrane switching multi-section type membrane stack filtering method provided by the invention solves the problem of imbalance of membrane elements in a multi-section type membrane stack device, reduces the operation cost of equipment, and has very important significance on the development of water purification equipment.

Description

Technical Field

[0001] The invention relates to the membrane field, and in particular to a membrane switching multi-stage membrane stack system. Background Art

[0002] In recent years, membrane technology, as a new water treatment technology, has been widely used in many water treatment fields. The existing reverse osmosis water purifier has a low raw water utilization rate, a wastewater ratio of about 1:3, a recovery rate of about 25%, and a large wastewater discharge, resulting in a waste of water resources. For this reason, the National Standardization Administration proposed and formulated the "Water Efficiency Limit Values ​​and Water Efficiency Grades for Water Purifiers", which stipulates that under the premise of meeting the nominal water purification flow rate and total water purification volume, the water efficiency grade of the water purifier is divided into 3 levels, namely, level 1 ≥ 65%, level 2 ≥ 55%, and level 3 ≥ 45%. Therefore, improving the recovery rate of water purification equipment is an urgent problem to be solved.

[0003] Recovery rate refers to the total recovery rate of water purification equipment in actual use, which is affected by many factors such as feed water quality, number of membrane elements and arrangement. Generally, in order to meet the requirements for water production and quality, most membrane devices adopt multi-component configuration. Membrane components are assembled in a certain configuration, in which the selection and optimization of the number of membrane components directly affect the separation effect, investment cost and operating cost of the device. The arrangement of membrane components in the device mainly includes single-stage, multi-stage, concentrated water circulation and graded. Among them, the multi-stage membrane stack device can improve the recovery rate of the device while meeting the requirements of water production quality.

[0004] A multi-stage membrane stack device is one that uses the concentrated water produced by the first stage device as the inlet water for the second stage device, and so on. Although this arrangement can effectively improve the recovery rate of the system, the poor water quality and slow flow rate of the concentrated water end lead to the imbalance of membrane performance in the multi-stage membrane stack device. Therefore, solving the problem of uneven membrane performance in the multi-stage membrane stack device and improving the utilization rate of each stage membrane component are of great significance to the development of water purification equipment. Summary of the invention

[0005] The purpose of the present invention is to overcome the shortcomings of the above-mentioned technical problems and provide a membrane switching multi-stage membrane stack system, which adds a solenoid valve for controlling the water inlet direction to the original multi-stage membrane stack device, and changes the problem of uneven membrane performance of the multi-stage membrane stack device by changing the water inlet direction.

[0006] To achieve the above-mentioned purpose, the technical solution adopted by the present invention is: A membrane switching multi-stage membrane stack filtration method comprises the following steps: S1. When the membrane switching multi-stage membrane stack filtration is working, the water inlet valve, electric switching valve and reverse concentrated water valve are opened, and the reverse water inlet valve, concentrated water valve and reverse electric switching valve are closed. The water flows into the first stage of the forward membrane stack device for filtration. The clean water enters the clean water main pipe through the water flow sensor. The concentrated water enters the subsequent membrane components of the forward membrane stack device in turn through the one-way valve for filtration, and then enters the reverse membrane stack device through the electric switching valve. After being filtered by multiple groups of membrane components, the clean water is collected into the clean water main pipe through the reverse clean water branch pipe, and the concentrated water finally flows out through the reverse concentrated water valve; S2. When the water flow sensor detects that the water flow rate reaches the limit value, the automatic control system controls the water inlet valve, the electric switching valve and the reverse concentrated water valve to close, and the reverse water inlet valve, the reverse electric switching valve and the concentrated water valve to open, the water inlet direction changes, and the water flows from the reverse water inlet solenoid valve into the reverse membrane stack device; S3. The water flows through the first section of the reverse membrane stack device for filtration, the clean water flows into the clean water main pipe through the water flow sensor, the concentrated water enters the subsequent membrane components of the reverse membrane stack device in turn through the reverse electric switching valve for filtration, and then enters the forward membrane stack device through the reverse electric switching valve; after being filtered by multiple groups of membrane components, the clean water flows into the clean water main pipe through the clean water branch pipe, and the concentrated water flows out through the concentrated water valve; S4. When the water flow sensor detects that the water flow rate reaches the limit again, the system maintenance personnel need to replace the membrane element to maximize the utilization rate of the membrane element.

[0007] The technical solution of the present invention has the following beneficial effects: The technical solution of the present invention is to change the water inlet direction by means of the solenoid valve that controls the water inlet direction on the multi-stage membrane stack device, and adjust the arrangement order of the membrane components. This method is beneficial to improving the utilization rate of each segment of the membrane components and improving the problem of uneven membrane performance in the multi-stage membrane stack device. At the same time, the utilization rate of concentrated water is improved, and the full utilization of water resources is achieved. The water flow sensor on the water purification branch can automatically control the change of water inlet direction according to the water flow conditions, and the operation and management are convenient. In summary, the membrane switching multi-stage membrane stack filtration method provided by the present invention solves the problem of uneven membrane performance in the multi-stage membrane stack device, reduces the operating cost of the equipment, and is of great significance to the development of water purification equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1 It is a schematic structural diagram of a membrane switching multi-stage membrane stack device of the present invention; Figure 2 It is a schematic structural diagram of a membrane switching two-stage membrane stack device of the present invention; Implementation

[0009] The embodiments of the present invention are now further described in conjunction with the accompanying drawings. These drawings are simplified schematic diagrams, which only illustrate the basic structure of the present invention in a schematic manner, and therefore only show the components related to the present invention. Example

[0010] The embodiment of the present invention provides a membrane switching multi-stage membrane stack filtration method, comprising the following steps: When the water is influent in the forward direction, the pretreated water flows through the water inlet 1 and enters the membrane switching forward membrane stack system. At this time, the water inlet valve 2 is in the open state and the reverse water inlet valve 3 is in the closed state. The water flows through the first membrane assembly 21 of the forward membrane stack device for filtration, and the filtered clean water flows into the clean water main pipe through the clean water branch pipe via the water flow sensors 211b, 212b...21nb; the concentrated water flows through the check valves 211a, 212a...21na and enters the concentrated water main pipe through the concentrated water branch pipe, and enters the 2nd, 3rd, 4th...nth membrane assembly of the forward membrane stack device in turn through the electric switching valve 21a for filtration, and the clean water flows through the clean water branch pipes of the 2nd, 3rd, 4th...nth membrane assembly in turn into the clean water main pipe. Main pipe; the concentrate enters the concentrate main pipe from the concentrate branch pipe, enters the reverse water inlet main pipe through the electric switching valve 2na, and flows through the reverse membrane stack device for filtration; at this time, the one-way valves 211a, 212a...21na...2n1a...2nna and the electric switching valves 21a...2na remain open, and the concentrate valves 21b...2nb remain closed; after the concentrate flows through the first membrane assembly of the reverse membrane stack device, the clean water passes through the water flow sensors 311b, 312b...31nb through the reverse The clean water branch flows into the clean water main pipe; the concentrated water flows into the reverse concentrated water branch pipe through the one-way valve 311a...31na, and merges into the reverse concentrated water main pipe, and enters the 2nd, 3rd, 4th...nth membrane assembly in turn through the reverse electric switching valve 31a for filtration, and the clean water passes through the reverse clean water branch pipes of the 2nd, 3rd, 4th...nth membrane assembly in turn and merges into the clean water main pipe; the concentrated water is merged into the reverse concentrated water main pipe from the reverse concentrated water branch pipe, and finally flows out through the reverse concentrated water valve 3nb; at this time, the one-way valves 311a, 312a...31na ...3n1a, 3n2a...3nna, the reverse electric switching valve 31a...3(n-1)a remains open, the reverse electric switching valve 3na remains closed, the reverse concentrated water valve 31b...3(n-1)b remains closed, and the reverse concentrated water valve 3nb remains open; when any water flow sensor detects that the concentrated water flow rate reaches the limit value, the automatic control system will close the water inlet valve 2, open the reverse water inlet valve 3, change the water inlet direction, and the water flows from the reverse water inlet valve 3 into the reverse membrane stack device; When reverse water inflow occurs, the pretreated water flows into the membrane switching reverse membrane stack system through the water inlet 1, the reverse water inlet solenoid valve 3 is opened, the water inlet valve 2 is closed, and the water flows through the first membrane assembly 31 of the reverse membrane stack device. The clean water flows out through the reverse clean water branch pipe through the water flow sensors 311b, 312b...31nb; the concentrated water flows out through the reverse concentrated water branch pipe through the one-way valves 311a, 312a...31na and merges into the reverse concentrated water main pipe, and then enters the second, third and fourth sections of the reverse concentrated water main pipe in sequence through the reverse electric switching valve 31a. 3, 4...n membrane modules are filtered, and the clean water is successively collected into the clean water main pipe through the reverse clean water branch pipe; the concentrated water is finally collected into the concentrated water main pipe through the reverse concentrated water branch pipe, enters the water inlet main pipe through the reverse electric switching valve 3na, and flows into the forward membrane stack device; at this time, the one-way valves 311a, 312a...31na...3n1a, 3n2a...3nna, the reverse electric switching valves 31a...3na remain in the open state, and the reverse concentrated water valves 31b...3nb remain in the closed state; the concentrated water flows through the forward membrane stack device After entering the first membrane module of the membrane stack device, the clean water flows into the clean water main pipe through the clean water branch pipe through the water flow sensors 211b, 212b...21nb; the concentrated water flows into the concentrated water branch pipe through the one-way valve 211a...21na, and merges into the concentrated water main pipe, and enters the 2nd, 3rd, 4th...nth membrane module in turn through the electric switching valve 21a for filtration. The clean water flows into the clean water main pipe through the clean water branch pipes of the 2nd, 3rd, 4th...nth membrane module in turn; the concentrated water flows into the concentrated water main pipe from the concentrated water branch pipe, and finally passes through the concentrated water valve 2n b flows out; at this time, the one-way valves 211a, 212a...21na...2n1a, 2n2a...2nna and the electric switching valve 21a...2(n-1)a remain open, the electric switching valve 2na remains closed, the concentrated water valve 21b...2(n-1)b remains closed, and the concentrated water valve 2nb remains open; when the water flow sensor detects that the water flow rate reaches the limit again, the system maintenance personnel need to replace the membrane element to maximize the utilization rate of the membrane element. Example

[0011] The embodiment of the present invention provides a membrane switching two-stage membrane stack filtration method, which is based on a membrane switching multi-stage reverse osmosis membrane stack filtration method provided in Example 1, and includes the following steps: When the water is influent in the forward direction, the pretreated water flows through the water inlet 1 and enters the membrane switching forward membrane stack system. At this time, the water inlet valve 2 is in the open state and the reverse water inlet valve 3 is in the closed state. The water flows through the membrane components 21 and 22 of the forward membrane stack device for filtration, and the clean water obtained after filtration flows out through the clean water branch pipe through the water flow sensors 21b and 22b; the concentrated water flows through the one-way valves 21a and 22a through the concentrated water branch pipe and merges into the concentrated water main pipe, enters the reverse water inlet main pipe through the electric switching valve 2a, and flows through the reverse two-stage membrane stack devices 31 and 32. At this time, the one-way valves 21a and 22a and the electric switching valve 2a remain in the open state, and the concentrated water valve 2b remains in the closed state; after the concentrated water flows through the reverse membrane stack device, the clean water passes through the water flow sensor 31b, 32b flow into the clean water main pipe through the reverse clean water branch pipe; the concentrated water flows into the reverse concentrated water branch pipe through the one-way valves 31a, 32a, merges into the reverse concentrated water main pipe, and flows out through the reverse concentrated water valve 3b; at this time, the one-way valves 31a, 32a, and the reverse concentrated water valve 3b remain open, and the reverse electric switching valve 3a remains closed; when any water flow sensor detects that the concentrated water flow rate reaches the limit value, the automatic control system will close the water inlet valve 2, open the reverse water inlet valve 3, change the water inlet direction, and the water flows from the reverse water inlet valve 3 into the reverse membrane stack device; When the water is fed in reverse, the pretreated water flows into the reverse membrane stack system through the water inlet 1. At this time, the reverse water inlet valve 3 is in the open state and the water inlet valve 2 is in the closed state. After the water flows through the membrane components 31 and 32 of the reverse membrane stack device, the clean water flows out through the reverse clean water branch pipe through the water flow sensors 31b and 32b; the concentrated water flows into the reverse concentrated water branch pipe through the one-way valves 31a and 32a, merges into the reverse concentrated water main pipe, and then enters the water inlet main pipe through the reverse electric switching valve 3a, and flows into the forward two-stage membrane stack device; at this time, the one-way valves 31a and 32a and the reverse electric switching valve 3a remain in the open state, and the reverse concentrated water valve 3b remains in the closed state; the concentrated water flows through the forward membrane stack device After the membrane components 21 and 22, the clean water flows into the clean water main pipe through the clean water branch pipe via the water flow sensors 21b and 22b; the concentrated water flows into the concentrated water branch pipe via the one-way valves 21a and 22a, merges into the concentrated water main pipe, and flows out through the concentrated water valve 2b; at this time, the one-way valves 31a and 32a and the electric switching valve 2a remain closed, and the concentrated water valve 2b remains open; when the water flow sensor detects that the water flow rate reaches the limit again, the system maintenance personnel need to replace the membrane element to maximize the utilization rate of the membrane element.

[0012] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or replace some of the technical features therein by equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A membrane switching multi-stage membrane stack filtration method, characterized in that: The following steps are involved: S1. When the membrane switching multi-stage membrane stack filtration is working, the water inlet valve, electric switching valve and reverse concentrated water valve are opened, and the reverse water inlet valve, concentrated water valve and reverse electric switching valve are closed. The water flows into the first stage of the forward membrane stack device for filtration. The clean water enters the clean water main pipe through the water flow sensor. The concentrated water enters the subsequent membrane components of the forward membrane stack device in turn through the one-way valve for filtration, and then enters the reverse membrane stack device through the electric switching valve. After being filtered by multiple groups of membrane components, the clean water is collected into the clean water main pipe through the reverse clean water branch pipe, and the concentrated water finally flows out through the reverse concentrated water valve; S2. When the water flow sensor detects that the water flow rate reaches the limit value, the automatic control system controls the water inlet valve, the electric switching valve and the reverse concentrated water valve to close, and the reverse water inlet valve, the reverse electric switching valve and the concentrated water valve to open, the water inlet direction changes, and the water flows from the reverse water inlet solenoid valve into the reverse membrane stack device; S3. The water flows through the first section of the reverse membrane stack device for filtration, the clean water flows into the clean water main pipe through the water flow sensor, the concentrated water enters the subsequent membrane components of the reverse membrane stack device in turn through the reverse electric switching valve for filtration, and then enters the forward membrane stack device through the reverse electric switching valve; after being filtered by multiple groups of membrane components, the clean water flows into the clean water main pipe through the clean water branch pipe, and the concentrated water flows out through the concentrated water valve; S4. When the water flow sensor detects that the water flow rate reaches the limit again, the system maintenance personnel need to replace the membrane element to maximize the utilization rate of the membrane element.

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