A multi-stage internal circulation and flushing cleaning device for a membrane system

Abstract

The present invention discloses a multi-stage internal circulation and flushing and cleaning device for a membrane system, comprising a raw water pipe, a produced water pipe, a concentrated water pipe and at least two membrane components, wherein the membrane components have a raw water inlet, a produced water outlet and a concentrated water outlet, and also comprise a cleaning pipeline, wherein the cleaning pipeline comprises a cleaning water inlet pipe connected to the raw water inlet of each membrane component, and a reagent addition port and a flushing water inlet valve arranged at the raw water inlet end of each membrane component. Since the present invention increases the cleaning pipeline and arranges the reagent addition port at the raw water inlet end of each membrane component, each membrane component can be added with a separate reagent for targeted cleaning, thereby improving the efficiency of reagent use and avoiding waste.

Description

Technical Field

[0001] The invention relates to a multi-stage internal circulation and flushing cleaning device for a membrane system. Background Art

[0002] Membrane systems, such as nanofiltration and reverse osmosis, have been widely used in the fields of material separation, purification, and refinement. In particular, nanofiltration and reverse osmosis have been widely used in the field of water treatment. In the practice of membrane water treatment, because the concentration at the interface between the membrane and the bulk solution or near the membrane interface area is getting higher and higher, under the action of the concentration gradient, the solute will diffuse from the membrane surface to the bulk solution to form a boundary layer, which increases the fluid resistance and local osmotic pressure, thereby causing the solvent permeation flux to decrease. This phenomenon is called concentration polarization. The main means to overcome this phenomenon is to reduce the accumulation of solute concentration in the membrane interface area by increasing the cross-flow on the membrane surface. In addition, membrane water treatment is also plagued by membrane fouling problems, and the pollution conditions at the front and back ends of the series membrane components are often different (for example, in the membrane water reuse, the front membrane component is usually biologically fouled and the back membrane component is usually physically fouled). The means to overcome this problem are usually to increase the dosing system during the operation stage and solve it through regular chemical cleaning of the membrane components.

[0003] The existing multi-stage membrane system usually has the following problems: 1. The existing multi-stage membrane system can only add cleaning agents through the water inlet end, and the different pollution conditions in the multi-stage membrane are cleaned with a unified agent, and the cleaning effect is poor. 2. In the existing multi-stage membrane system, the low-pressure flushing and high-pressure flushing processes both take in water from the water inlet end of the first-stage membrane component. After passing through the multi-stage membrane components, the water quality and water pressure at the end of the flushing are seriously attenuated, and the flushing effect is not good, or in order to have a good flushing process, the flushing time needs to be extended. 3. For the existing multi-stage membrane system, for the multi-stage membrane system, the cleaning process also takes in water from the water inlet end of the entire membrane system, and it is impossible to carry out targeted agent ratios for a specific segment of the membrane component, resulting in agent waste and the cleaning process cannot achieve the right medicine. 4. There is no manual valve on the circulation return pipeline. The circulation flow can only be adjusted through the circulation pump and the circulation pump outlet valve, and the circulation flow and membrane pressure cannot be fully and accurately adjusted. Summary of the invention

[0004] The purpose of the present invention is to provide a multi-stage internal circulation and flushing cleaning device for a membrane system capable of adding chemicals to and cleaning membrane components of different stages respectively.

[0005] To achieve the above-mentioned purpose, the technical solution adopted by the present invention is: a multi-stage internal circulation and flushing and cleaning device for a membrane system, which includes a raw water pipe, a produced water pipe, a concentrated water pipe and at least two membrane components, the membrane components have a raw water inlet, a produced water outlet and a concentrated water outlet, and also include a cleaning pipeline, the cleaning pipeline includes a cleaning water inlet pipe connected to the raw water inlet of each of the membrane components, and a reagent addition port and a flushing water inlet valve arranged at the raw water inlet end of each of the membrane components.

[0006] Preferably, two membrane components are provided, namely a first-stage membrane component and a second-stage membrane component. The concentrated water outlet of the first-stage membrane component is connected to the raw water inlet of the second-stage membrane component. The water production pipe is respectively connected to the water production outlet of the first-stage membrane component and the water production outlet of the second-stage membrane component. The concentrated water pipe is connected to the concentrated water outlet of the second-stage membrane component. The cleaning pipeline also includes a cleaning drain pipe and a cleaning pump arranged at the water inlet end of the cleaning water inlet pipe. The cleaning water inlet pipe is respectively connected to the raw water inlet of the first-stage membrane component and the raw water inlet of the second-stage membrane component. The cleaning drain pipe is respectively connected to the concentrated water outlet of the first-stage membrane component and the concentrated water outlet of the second-stage membrane component.

[0007] Further preferably, a first flushing water inlet valve is arranged between the cleaning water inlet pipe and the raw water inlet of the first-stage membrane component, and a second flushing water inlet valve is arranged between the cleaning water inlet pipe and the raw water inlet of the second-stage membrane component; a first concentrated water valve is arranged between the cleaning drain pipe and the concentrated water outlet of the first-stage membrane component, and a second concentrated water valve is arranged between the cleaning drain pipe and the concentrated water outlet of the second-stage membrane component; a first flushing discharge valve is arranged between the concentrated water pipe and the concentrated water outlet of the first-stage membrane component, and a second flushing discharge valve is arranged between the concentrated water pipe and the concentrated water outlet of the second-stage membrane component; a first water production check valve and a first water production valve are arranged between the water production pipe and the water production outlet of the first-stage membrane component, and a second water production check valve and a second water production valve are arranged between the water production pipe and the water production outlet of the second-stage membrane component.

[0008] More preferably, it also includes a circulation pipeline which is connected to the raw water inlet of the membrane module and the concentrated water outlet of the membrane module respectively, and a circulation pump and a reagent addition port are arranged in series on the circulation pipeline.

[0009] Further preferably, a circulating pump outlet valve and a check valve are provided at the outlet of the circulating pump, and the reagent addition port is provided at the outlet end of the circulating pump.

[0010] More preferably, it also includes a second-stage circulation pipeline respectively connecting the raw water inlet of the second-stage membrane assembly and the concentrated water outlet of the second-stage membrane assembly, and a second-stage circulation pump and a second-stage reagent addition port are arranged in series on the second-stage circulation pipeline.

[0011] More preferably, it also includes a filtering circulation pipeline connecting the concentrated water outlet of the first-stage membrane assembly and the inlet of the second-stage circulation pump.

[0012] Further preferably, a second-stage circulation pump outlet valve and a second-stage check valve are provided at the outlet of the second-stage circulation pump, and the second-stage reagent addition port is provided at the outlet end of the second-stage circulation pump.

[0013] Further preferably, the raw water pipe is provided with a filter inlet valve, a safety filter, a filter outlet valve, a high-pressure pump, a high-pressure pump check valve, a system inlet valve and a high-pressure pump outlet valve in sequence; the concentrated water pipe is provided with a concentrated water regulating valve and a concentrated water electric valve in sequence.

[0014] Preferably, the membrane assembly comprises a plurality of membrane units arranged in parallel.

[0015] Due to the application of the above technical solution, the present invention has the following advantages compared with the prior art:

[0016] By adding a circulation pump to each section, a concentrated water reflux valve to each section, a cleaning / flushing inlet to each section, and a dosing port to each section, the present invention can accurately control the circulation pressure, circulation flow, dosing amount, dosing type, cleaning agent type, flushing frequency, and flushing intensity of each end membrane component, thereby achieving refined operation of the membrane system. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Attached Figure 1 It is a schematic diagram of the principle of the present invention.

[0018] In the above figures: 11, first-stage membrane assembly; 12, second-stage membrane assembly; 24, cleaning water inlet pipe; 31, first-stage flushing water inlet valve; 32, first-stage concentrated water valve; 33, first-stage flushing discharge valve; 34, first-stage water production check valve; 35, first-stage water production valve; 36, first-stage circulating pump outlet valve; 37, first-stage check valve; 41, second-stage flushing water inlet valve; 42, second-stage concentrated water valve; 43, second-stage flushing discharge valve; 44, second-stage water production check valve; 45, second-stage water production valve; 46, second-stage circulating pump outlet valve; 47. Second-stage check valve; 51. First-stage reagent inlet; 52. Second-stage reagent inlet; 61. First-stage circulation pump; 62. Second-stage circulation pump; 71. Filter inlet valve; 72. Safety filter; 73. Filter outlet valve; 74. High-pressure pump; 75. High-pressure pump check valve; 76. System inlet valve; 77. High-pressure pump outlet valve; 81. Concentrated water regulating valve; 82. Concentrated water electric valve; 91. Cleaning reflux valve; 92. Flushing reflux valve; 93. Produced water cleaning reflux valve; 94. Produced water valve. DETAILED DESCRIPTION

[0019] The present invention will be further described below in conjunction with the embodiments shown in the accompanying drawings:

[0020] See attached Figure 1 As shown, a multi-stage internal circulation and flushing and cleaning device of a membrane system comprises a first-stage membrane assembly 11, a second-stage membrane assembly 12, a raw water tank, a production water tank, a concentrate water tank, a cleaning water tank, a raw water pipe connecting the raw water tank and the raw water inlet of the first-stage membrane assembly 11, a production water pipe connecting the production water tank with the production water outlet of the first-stage membrane assembly 11 and the production water outlet of the second-stage membrane assembly 12, a concentrate water pipe connecting the concentrate water tank with the concentrate water outlet of the second-stage membrane assembly 12, a cleaning water inlet pipe 24 connecting the cleaning water tank with the raw water inlet of the first-stage membrane assembly 11 and the raw water inlet of the second-stage membrane assembly 12, a cleaning pump (not shown in the figure) arranged between the cleaning water inlet pipe 24 and the cleaning water tank, and a cleaning drainage pipe connecting the cleaning water tank with the concentrate water outlet of the first-stage membrane assembly 11 and the concentrate water outlet of the second-stage membrane assembly 12. Wherein, the first-stage membrane assembly 11 and the second-stage membrane assembly 12 each comprise a plurality of membrane units arranged in parallel.

[0021] Specifically, a first flushing water inlet valve 31 is arranged between the cleaning water inlet pipe 24 and the raw water inlet of the first-stage membrane assembly 11, and a second flushing water inlet valve 41 is arranged between the cleaning water inlet pipe 24 and the raw water inlet of the second-stage membrane assembly 12; a first concentrate water valve 32 is arranged between the concentrate water pipe and the concentrate water outlet of the first-stage membrane assembly 11, and a second concentrate water valve 42 is arranged between the concentrate water pipe and the concentrate water outlet of the second-stage membrane assembly 12; a first flushing discharge valve 33 is arranged between the cleaning drain pipe and the concentrate water outlet of the first-stage membrane assembly 11, and a second flushing discharge valve 43 is arranged between the cleaning drain pipe and the concentrate water outlet of the second-stage membrane assembly 12; a first water production check valve 34 and a first water production valve 35 are arranged between the water production pipe and the water production outlet of the first-stage membrane assembly 11, and a second water production check valve 44 and a second water production valve 45 are arranged between the water production pipe and the water production outlet of the second-stage membrane assembly 12.

[0022] The device of this embodiment also includes a circulation pipeline connecting the raw water inlet of the first membrane assembly 11 and the concentrated water outlet of the first membrane assembly 11, a circulation pump 61 and a reagent addition port 51 are arranged in series on the circulation pipeline, and a filtering circulation pipeline connecting the concentrated water outlet of the first membrane assembly 11 and the inlet of the second circulation pump 62. Among them, a circulation pump outlet valve 36 and a check valve 37 are arranged at the outlet of the first circulation pump 61, and the reagent addition port 51 is arranged at the outlet end of the first circulation pump 61.

[0023] The device of this embodiment also includes a second-stage circulation pipeline respectively connected to the raw water inlet of the second-stage membrane assembly 12 and the concentrated water outlet of the second-stage membrane assembly 12, and a second-stage circulation pump 62 and a second-stage reagent addition port 52 are arranged in series on the second-stage circulation pipeline. Among them, a second-stage circulation pump outlet valve 46 and a second-stage check valve 47 are arranged at the outlet of the second-stage circulation pump 62, and the second-stage reagent addition port 52 is arranged at the outlet end of the second-stage circulation pump 62.

[0024] In this embodiment, the raw water pipe is provided with a filter inlet valve 71, a safety filter 72, a filter outlet valve 73, a high-pressure pump 74, a high-pressure pump check valve 75, a system inlet valve 76 and a high-pressure pump outlet valve 77 in sequence; the concentrated water pipe is provided with a concentrated water regulating valve 81 and a concentrated water electric valve 82 in sequence.

[0025] In addition, a cleaning return valve 91 is provided between the cleaning drain pipe and the cleaning water tank, and the cleaning drain pipe is also connected to the raw water tank through a flushing return valve 92. A water production valve 94 is provided between the water production pipe and the water production tank, and a water production cleaning return valve 93 is provided between the water production pipe and the cleaning water tank.

[0026] This embodiment has the following working states:

[0027] 1. The membrane system is in operation. The filter inlet valve 71, the filter outlet valve 73, the system inlet valve 76, the high-pressure pump outlet valve 77, the first-stage circulation pump outlet valve 36, the first-stage concentrated water valve 32, the second-stage circulation pump outlet valve 46, the second-stage concentrated water valve 42, the concentrated water regulating valve 81, the concentrated water electric valve 82, the first-stage water production valve 35, the second-stage water production valve 45, and the water production valve 94 are opened. The other valves are closed. Raw water enters the raw water pipe from the raw water tank. The operating pressure and flow of each section are controlled by opening the speed of the high-pressure pump 74, the first-stage circulation pump 61, and the second-stage circulation pump 62, and adjusting the opening of the first-stage concentrated water valve 32 and the second-stage concentrated water valve 42, so that the raw water is filtered through the first-stage membrane assembly 11 and the second-stage membrane assembly 12. The system operation recovery rate is adjusted by the opening of the concentrated water regulating valve 81.

[0028] When the membrane system is in operation, in this embodiment, the reagents used in each stage are added through the first stage reagent addition port 51 and the second stage reagent addition port 52. Both the first stage reagent addition port 51 and the second stage reagent addition port 52 are provided with a check valve. For example, a large amount of bactericide and a small amount of antiscalant are added to the first stage reagent addition port 51 to inhibit biological scaling; a large amount of antiscalant and a small amount of bactericide are added to the second stage reagent addition port 52 to inhibit inorganic scaling.

[0029] 2. High-pressure flushing state, which includes a first-stage high-pressure flushing state and a second-stage high-pressure flushing state.

[0030] A first stage of high pressure flushing state, that is, when the membrane system is in operation, a first stage of flushing discharge valve 33 and a flushing reflux valve 92 are opened;

[0031] The second-stage high-pressure flushing state, that is, when the membrane system is in operation, the second-stage flushing discharge valve 43 and the flushing reflux valve 92 are opened.

[0032] In the high-pressure flushing state, the flushing water is sent into the raw water tank through the cleaning drain pipe.

[0033] The water flow velocity and pressure in the tube of the membrane unit in the high-pressure flushing state and the membrane system operation state can be automatically achieved by controlling the operating frequency of the first-stage circulation pump 61 and the second-stage circulation pump 62 by the frequency converter.

[0034] 3. Low-pressure flushing state, specifically including the first-stage low-pressure flushing state and the second-stage low-pressure flushing state.

[0035] In the first stage low pressure flushing state, the first stage flushing water inlet valve 31, the first stage flushing discharge valve 33, the flushing return valve 92, and the cleaning pump are opened, and other valves are closed and the water pump is stopped;

[0036] In the second-stage low-pressure flushing state, the second-stage flushing water inlet valve 41, the second-stage flushing discharge valve 43, the flushing return valve 92, and the cleaning pump are opened, and other valves are closed and the water pump is stopped.

[0037] In the low-pressure flushing state, the water in the cleaning water tank enters the first-stage membrane assembly 11 and the second-stage membrane assembly 12 through the cleaning pump, and the flushed water flow is sent to the raw water tank through the cleaning drain pipe.

[0038] 4. Chemical cleaning state, which includes one-stage chemical cleaning and two-stage chemical cleaning.

[0039] In the first stage chemical cleaning state, the first stage flushing water inlet valve 31, the first stage flushing discharge valve 33, the cleaning return valve 91, the produced water cleaning return valve 93, and the cleaning pump are opened, and other valves are closed and the water pump is stopped;

[0040] When the second-stage chemical cleaning state is in progress, the second-stage flushing water inlet valve 41, the second-stage flushing discharge valve 43, the cleaning return valve 91, the produced water cleaning return valve 93, and the cleaning pump are opened, and other valves are closed and the water pump is stopped.

[0041] In the chemical cleaning state, the water flow in the cleaning tank is pumped into the first-stage membrane assembly 11 and the second-stage membrane assembly 12 by the cleaning pump, and the cleaning water is returned to the cleaning tank through the cleaning reflux valve 91 and the produced water cleaning reflux valve 93 to form a cleaning liquid circulation.

[0042] In the chemical cleaning state, different cleaning agents can be injected into the cleaning tank or the first-stage agent injection port 51 and the second-stage agent injection port 52 according to the pollution conditions of each stage. For example, alkali is injected in the first-stage cleaning to clean biological pollution; acid is injected in the second-stage cleaning to clean inorganic scaling.

[0043] Compared with the prior art, this embodiment has the following advantages:

[0044] 1. The first-stage membrane assembly 11 and the second-stage membrane assembly 12 can be cleaned separately by injecting specific reagents as needed.

[0045] 2. The first-stage membrane assembly 11 and the second-stage membrane assembly 12 have their own circulation pumps, which can accurately control the circulation pressure of each stage of the membrane assembly to achieve refined operation of the membrane system.

[0046] 3. A separate agent can be added to the first-stage membrane assembly 11 or the second-stage membrane assembly 12 for targeted cleaning, thereby improving the efficiency of agent use and avoiding waste.

[0047] The above embodiments are only for illustrating the technical concept and features of the present invention, and their purpose is to enable people familiar with the technology to understand the content of the present invention and implement it accordingly, and they cannot be used to limit the protection scope of the present invention. Any equivalent changes or modifications made according to the spirit of the present invention should be included in the protection scope of the present invention.

Claims

1. A multi-stage internal circulation and flushing cleaning device for a membrane system, comprising a raw water pipe, a produced water pipe, a concentrated water pipe and at least two membrane modules, wherein the membrane modules have a raw water inlet, a produced water outlet and a concentrated water outlet, and are characterized in that: It also includes a cleaning pipeline, a cleaning water tank, a production water tank, and a raw water tank. The cleaning pipeline includes a cleaning water inlet pipe connected to the raw water inlet of each membrane module, and a reagent addition port and a flushing water inlet valve arranged at the raw water inlet end of each membrane module; The membrane assembly is provided with two, namely a first-stage membrane assembly and a second-stage membrane assembly, the concentrated water outlet of the first-stage membrane assembly is connected to the raw water inlet of the second-stage membrane assembly, the produced water pipe is respectively connected to the produced water outlet of the first-stage membrane assembly and the produced water outlet of the second-stage membrane assembly, the concentrated water pipe is connected to the concentrated water outlet of the second-stage membrane assembly, the cleaning pipeline also includes a cleaning drain pipe and a cleaning pump arranged at the water inlet end of the cleaning water inlet pipe, the cleaning water inlet pipe is respectively connected to the raw water inlet of the first-stage membrane assembly and the raw water inlet of the second-stage membrane assembly, and the cleaning drain pipe is respectively connected to the concentrated water outlet of the first-stage membrane assembly and the concentrated water outlet of the second-stage membrane assembly; A first flushing water inlet valve is provided between the cleaning water inlet pipe and the raw water inlet of the first-stage membrane assembly, and a second flushing water inlet valve is provided between the cleaning water inlet pipe and the raw water inlet of the second-stage membrane assembly; a first concentrated water valve is provided between the concentrated water pipe and the concentrated water outlet of the first-stage membrane assembly, and a second concentrated water valve is provided between the concentrated water pipe and the concentrated water outlet of the second-stage membrane assembly; A first flushing discharge valve is provided between the cleaning drain pipe and the concentrated water outlet of the first-stage membrane assembly, a second flushing discharge valve is provided between the cleaning drain pipe and the concentrated water outlet of the second-stage membrane assembly, a first water production check valve and a first water production valve are provided between the water production pipe and the water production outlet of the first-stage membrane assembly, and a second water production check valve and a second water production valve are provided between the water production pipe and the water production outlet of the second-stage membrane assembly; It also includes a section of circulation pipeline respectively connected to the raw water inlet of the section of membrane assembly and the concentrated water outlet of the section of membrane assembly, and a section of circulation pump and a section of reagent addition inlet are arranged in series on the section of circulation pipeline; It also includes a two-stage circulation pipeline respectively connected to the raw water inlet of the two-stage membrane assembly and the concentrated water outlet of the two-stage membrane assembly, wherein a two-stage circulation pump and a two-stage reagent addition port are arranged in series on the two-stage circulation pipeline; a two-stage circulation pump outlet valve and a two-stage check valve are arranged at the outlet of the two-stage circulation pump, and the two-stage reagent addition port is arranged at the outlet end of the two-stage circulation pump; a filter water inlet valve, a safety filter, a filter outlet valve, a high-pressure pump, a high-pressure pump check valve, a system water inlet valve and a high-pressure pump outlet valve are arranged in sequence on the raw water pipe; a concentrated water regulating valve and a concentrated water electric valve are arranged in sequence on the concentrated water pipe; It also includes a filtering circulation pipeline connecting the concentrated water outlet of the first-stage membrane assembly and the inlet of the second-stage circulation pump; a first-stage circulation pump outlet valve and a first-stage check valve are arranged at the outlet of the first-stage circulation pump, and the first-stage reagent addition port is arranged at the outlet end of the first-stage circulation pump; A cleaning reflux valve is provided between the cleaning drainage pipe and the cleaning water tank, and the cleaning drainage pipe is also connected to the raw water tank through the flushing reflux valve; a water production valve is provided between the water production pipe and the water production tank, and a water production cleaning reflux valve is provided between the water production pipe and the cleaning water tank; The membrane assembly includes a plurality of membrane units arranged in parallel.

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