A small-scale error flow nanofiltration membrane module

Abstract

The application provides a small-scale cross-flow nanofiltration membrane module, which comprises a detachable stainless steel shell and a flat sheet membrane core. The shell comprises an upper shell and a lower shell. The upper shell comprises an upper inner cavity, a feed inlet and a cross-flow outlet arranged at an angle with the feed inlet. The feed inlet and the cross-flow outlet are communicated with the upper inner cavity. When a high-pressure pump pumps in feed liquid, the unmembrane-passed feed liquid is backflowed to the feed liquid for circulation by the cross-flow outlet under the action of membrane resistance. The lower shell comprises a lower cavity, a permeate outlet and a lower inner cavity, which are communicated. The upper shell and the lower shell are sealed. The inner sealing of the nest comprises a convex groove of the upper shell and a sealing ring in the groove, which is used for preventing the leakage of the unmembrane-passed inner side. The outer sealing for preventing the leakage of the feed liquid comprises a concave groove of the lower shell and a sealing ring in the groove. The movable supporting hole plate supports the filter membrane to prevent the membrane from being damaged by the excessive pressure of the feed liquid. The upper shell and the lower shell are fastened by four stainless steel screw rods. The application can solve the problems of single membrane area size and poor sealing of the commercial small-scale nanofiltration membrane module.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of membrane filtration, in particular, and especially relates to a small test cross-flow nanofiltration membrane module. BACKGROUND

[0002] Nanofiltration (NF) is a pressure-driven membrane separation process between reverse osmosis and ultrafiltration, and the pore size of nanofiltration membrane is about several nanometers. Compared with other pressure-driven membrane separation processes, it appeared late. Its appearance can be traced back to the research of J.E.Cadotte's NS-300 membrane in the late 70s, and after that, nanofiltration developed very quickly, and membrane modules were commercialized in the mid-80s. Nanofiltration membranes are mostly derived from reverse osmosis membranes, such as CA, CTA membranes, aromatic polyamide composite membranes and sulfonated polyether sulfone membranes, etc. Nanofiltration is a green water treatment technology, which can replace traditional high-cost and complex process wastewater treatment methods in some aspects. The characteristics of nanofiltration technology are: it can intercept organic matter with a molecular weight greater than 100 and multivalent ions, and allow small-molecule organic matter and monovalent ions to pass through; it can operate under harsh conditions such as high temperature, acid and alkali, and is resistant to pollution; the operating pressure is low, the membrane flux is high, and the device operating cost is low; it can be combined with other wastewater treatment processes to further reduce costs and improve treatment effect. In water treatment, nanofiltration membranes are mainly used for the treatment of solvent-containing wastewater, which can effectively remove color, hardness and odor in water. NF membranes have been successfully applied to wastewater treatment in industries such as sugar production, pulp and papermaking, electroplating, mechanical processing and chemical reaction catalyst recovery due to their special separation performance.

[0003] The small test cross-flow nanofiltration membrane module is a combination of nanofiltration membranes fixed in the membrane module and the feed liquid connected to the high-pressure pump. At present, the most commonly used small test experiment is the cross-flow cavity type membrane module, which can be composed of only upper and lower cavities, lower cavity membrane support hole plates, inner sealing rings and outer sealing rings, and the structure is similar to a general needle filter. However, the cross-flow membrane reactor used in the laboratory is mostly self-made by laboratory personnel using various types of plates, resulting in no unified standard for small test nanofiltration cross-flow experiments, large data errors, and inability to scientifically evaluate nanofiltration membrane performance parameters. For the current research on nanofiltration membranes modified by interfacial polymerization technology, the size of the commercial nanofiltration membrane module cannot meet the demand. SUMMARY

[0004] The application provides a small-scale cross-flow nanofiltration membrane assembly, which comprises a detachable stainless steel shell, a nested inner sealing structure, a leakage-proof outer sealing structure and a flat membrane core.

[0005] The application adopts the following technical means:

[0006] The small-scale cross-flow nanofiltration membrane assembly comprises a stainless steel shell and a flat membrane core, the detachable shell comprises detachably connected upper and lower shells, and the inner sides of the upper and lower shells are sealingly connected.

[0007] The upper shell comprises a feed inlet, a cross-flow outlet arranged at an angle with the feed inlet and an upper inner cavity, the upper inner cavity is arranged in the interior of the upper shell, the feed inlet is connected to the axial outer end of the upper shell, the cross-flow outlet is connected to the side wall of the upper shell, and the inner ends of the feed inlet and the cross-flow outlet are in communication with the interior of the upper inner cavity.

[0008] Further, the feed inlet and the cross-flow outlet are arranged at an angle of 90 degrees.

[0009] Further, after the feed liquid enters the upper inner cavity through the feed inlet, the feed liquid can only flow out from the cross-flow outlet arranged at an angle of 90 degrees with the feed inlet under the action of membrane resistance, the cross flow is formed in the upper inner cavity under the action of horizontal shear force, the membrane surface pollution of the feed liquid is slowed down, and the water flux is maintained.

[0010] Further, the lower inner cavity and the upper inner cavity are provided with a movable supporting hole plate for supporting the filter membrane.

[0011] Further, the upper shell and the lower shell are respectively provided with the nested inner sealing structure and the leakage-proof outer sealing structure.

[0012] Further, the nested inner seal is a groove on the upper shell of stainless steel, which is filled with an upper shell groove sealing ring, and the upper shell groove sealing ring is pressed on the upper layer of the filter membrane or film placed on the movable support hole plate, preventing the feed liquid from leaking into the lower cavity from the periphery.

[0013] Further, the movable support hole plate is placed in the lower shell concave hole plate groove on the lower shell, and the movable support hole plate, the lower shell concave hole plate groove, the filter membrane, and the upper shell groove membrane inner sealing ring are coaxially arranged and the outer periphery projection coincides.

[0014] Further, the upper shell and the lower shell are both disc-shaped structures, and four through-thread holes are arranged on the upper shell near the outer edge of the disc along the circumferential direction, which are distributed on the outer side of the upper inner cavity; four through-thread holes are arranged on the lower shell near the outer edge of the disc along the circumferential direction, which are distributed on the outer side of the lower inner cavity; the upper and lower thread holes are coaxially arranged, and are fastened by a stainless steel screw rod and a stainless steel butterfly nut.

[0015] Compared with the prior art, the present application has the following advantages:

[0016] The small-scale cross-flow nanofiltration membrane assembly provided by the present application has good sealing performance, corrosion resistance, and easy processing. The double-sealing design can effectively prevent the feed liquid from leaking into the outer side of the unfiltered membrane, providing reliable nanofiltration high transmembrane pressure difference test conditions.

[0017] In summary, the technical solution of the present application can solve the problem of single membrane area size and poor sealing performance of nanofiltration assemblies on the market.

[0018] Based on the above reasons, the present application can be widely used in the fields of cross-flow filtration and nanofiltration. BRIEF DESCRIPTION OF DRAWINGS

[0019] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiment or prior art description. Obviously, the drawings in the following description are some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without creative labor.

[0020] Figure 1 The present application is a laboratory nanofiltration small-scale cross-flow membrane reactor axial measurement schematic diagram.

[0021] Figure 2Three view of the shell and membrane assembly of the nanofiltration pilot scale crossflow membrane reactor for laboratory use, wherein (a) is the front view, (b) is the side view, and (c) is the top view.

[0022] Figure 3 The schematic diagram of the whole disassembly of the present application.

[0023] Figure 4 The schematic diagram of the lower shell of the present application, wherein (a) is the isometric view, (b) is the front view, (c) is the side view, and (d) is the top view.

[0024] Figure 5 The schematic diagram of the upper shell of the present application, wherein (a) is the isometric view, (b) is the front view, (c) is the side view, and (d) is the top view.

[0025] Figure 6 The schematic diagram of the whole of the present application, wherein (a) is the perspective view, and (b) is the transparent view.

[0026] In the figure: 1, feed inlet; 2, crossflow outlet; 3, upper shell convex groove membrane pressing inner sealing ring; 4, lower shell concave groove shell pressing outer sealing ring; 5, movable supporting hole plate; 6, lower cavity permeate outlet; 7, stainless steel butterfly nut; 8, stainless steel screw rod; 9, lower shell concave hole plate groove; 10, lower inner cavity; 11, permeate outlet pipe; 12, lower shell leakage-proof outer sealing groove; 13, feed inlet pipe; 14, crossflow outlet pipe; 15, upper inner cavity; 16, upper shell nested inner sealing convex groove. DETAILED DESCRIPTION

[0027] It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0028] In order to make the purpose, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly and completely below in combination with the drawings of the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, but not all the embodiments. The description of the at least one exemplary embodiment is actually only illustrative, but not as any limitation on the present application and its application or use. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0029] It is to be understood that the terms so far as the grammar used herein is concerned are to be interpreted in their dictionary meanings and are not to be interpreted in the context of legal terms unless so explicitly stated. It is also to be understood that the terminology and description provided above are for the purpose of simplifying the present disclosure and the invention, and are not intended to limit the scope of the application of the present invention, and the use of such terminology, and description is understood to also cover any technical equivalents for the subject matter covered. It is also to be understood that the terminology and description provided above are for the purpose of simplifying the present disclosure and the invention, and are not intended to limit the scope of the application of the present invention, and the use of such terminology, and description is understood to also cover any technical equivalents for the subject matter covered.

[0030] The relative arrangement of parts and steps, numerical expressions, and numerical values set forth in the examples are not intended to limit the scope of the application unless specifically so stated. It is also to be understood that the drawings are not necessarily drawn to scale and that the dimensions of the various parts shown in the drawings are intended to be illustrative only and not limiting of the scope of the application. Techniques, methods, and apparatus known to those of ordinary skill are not discussed in detail but can be employed with the systems and methods described herein. Any specific values recited in the examples are to be interpreted as illustrative only and not limiting of the scope of the application. Other examples of the exemplary embodiments can have different values. It is noted that like numbers and letters on the figures identify like parts throughout the disclosure, and that the use of the same numbers and letters in different figures indicates similar or identical elements.

[0031] In the description of the present application, it is to be understood that the orientation or positional relationships indicated by terms such as "front", "back", "upper", "lower", "left", "right", "horizontal", "vertical", "top", "bottom", and the like are based on the orientation or positional relationships shown in the drawings, and are used only for the purpose of facilitating the description of the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a particular orientation or be constructed and operated in a particular orientation, and therefore should not be construed as limiting the scope of protection of the present application. The orientation terms "inner", "outer" refer to the inner and outer relative to the outline of the components themselves.

[0032] For purposes of the description hereinafter, spatial relative terms, such as "above", "below", "upper", "lower", and the like, can be used to describe the relative position of one element or feature to another element or feature as illustrated in the figures. It will be understood that the spatial relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientations depicted in the figures. For example, if the device in the figures is turned over, elements described as "above" or "below" other elements or features would then be oriented "below" or "above" other elements or features. Thus, the exemplary term "above" can encompass both an orientation of above and below. The device can be otherwise oriented (rotated 90 degrees or at other orientations) and the spatial relative descriptors used herein interpreted accordingly.

[0033] In addition, it should be noted that the use of "first", "second", and the like words of distinction do not connote any actual physical or chronological order, but are merely used for convenience and clarity in identifying one element from another. Unless otherwise stated, the use of these words is not intended to imply a special relationship or order among the elements, and these terms are not intended to imply a special chronological or physical order among elements. Thus, these terms, to the extent they can be deemed to connote a special or chronological order, are used herein for ease of description and are in no way deemed to limit the scope of the present application.

[0034] As shown in the drawings, Figures 1-6 The present application provides a small test cross-flow nanofiltration membrane module, which is a small test cross-flow membrane reactor processed by milling grooves from stainless steel material. The module comprises a detachable stainless steel shell, a nested inner sealing structure, a leakage-proof outer sealing structure, and a flat membrane core. The flat membrane core is installed inside the shell. The shell comprises an upper shell and a lower shell. The upper shell comprises an upper inner cavity, a feed inlet, and a cross-flow outlet at a right angle to the feed inlet. The upper inner cavity is arranged inside the upper shell. The feed inlet is connected to the axial outer end of the upper shell. The cross-flow outlet is connected to the sidewall of the upper shell. The feed inlet and the cross-flow outlet are in communication with the upper inner cavity. When the high-pressure pump pumps in the feed liquid, the un-membrane-passed feed liquid is returned to the feed liquid for circulation by the cross-flow outlet under the action of membrane resistance. The lower shell comprises a lower cavity and a permeate liquid outlet. The two are in communication. The upper and lower shells are sealed. The nested inner sealing structure comprises a convex groove of the upper shell and a sealing ring in the groove, which is used to prevent leakage on the inner side of the un-membrane-passed feed liquid. The leakage-proof outer sealing structure comprises a concave groove of the lower shell and a sealing ring in the groove, which is used to prevent leakage of the feed liquid. The flat membrane core comprises a filter membrane installed between the lower inner cavity and the upper inner cavity. A movable support hole plate supports the filter membrane to prevent the membrane from being damaged by excessive pressure of the feed liquid. The upper and lower shells are fastened by four stainless steel screw rods. The present application can solve the problems of single membrane area size and poor sealing performance of commercial small test nanofiltration membrane modules.

[0035] Specifically, the small test cross-flow nanofiltration membrane module comprises Figure 1The feed inlet 1, the cross-flow outlet 2, the upper shell convex groove membrane-pressing inner sealing ring 3, the lower shell concave groove shell-pressing outer sealing ring 4, the movable supporting hole plate 5, the lower cavity permeate outlet 6, the stainless steel butterfly nut 7, and the stainless steel screw rod 8 are arranged in the membrane module.

[0036] The membrane module is fixed by screwing the stainless steel butterfly nut 7 (four groups in total, each group containing a gasket) on the four stainless steel screw rods 8. The upper cavity feed inlet 1 and the upper cavity cross-flow outlet 2 and the internal cavity are combined as an upper shell. The outer periphery of the filter membrane is fixed on the movable supporting hole plate 5 by the circular upper shell convex groove membrane-pressing inner sealing ring 3. An upper shell nesting inner sealing convex groove 16 is processed on the upper shell by milling. The upper shell convex groove membrane-pressing inner sealing ring 3 is filled in the upper shell nesting inner sealing convex groove 16. The upper and lower shell discs are sealed along the interval by the lower shell concave groove shell-pressing outer sealing ring 4. The movable supporting hole plate 5 is a stainless steel disc with a diameter of 40 mm and a thickness of 3 mm, and is filled with holes with a diameter of 0.5 mm. The movable supporting hole plate 5 is located in the lower shell concave hole plate groove 9. When the filter membrane is replaced, the hole plate can be taken out. The lower cavity permeate outlet 6 collects the permeate.

[0037] The upper and lower shells of the membrane module are disc-shaped, and the diameters are both 50 mm, and the thickness is 20 mm. In this embodiment, the upper and lower shells are coaxial and arranged in the axial direction. The end face of the upper shell close to the lower shell is the rear end face, and the end face of the upper shell away from the lower shell is the front end face. The end face of the lower shell close to the upper shell is the front end face, and the end face of the lower shell away from the upper shell is the rear end face.

[0038] The lower shell is composed of the lower shell concave groove shell-pressing outer sealing ring 4, the lower shell concave hole plate groove 9, the lower inner cavity 10, and the lower cavity permeate outlet 6. The lower inner cavity 10 is opened from the front end face of the lower shell to the inside of the lower shell (not penetrating through the rear end face of the lower shell). The opening of the lower cavity inner cavity 10 at the front end face of the lower shell is an inlet. The lower shell concave hole plate groove 9 is opened at the inlet. The movable supporting hole plate 5 is placed in the lower shell concave hole plate groove 9. One end of the lower cavity permeate outlet 6 is connected with the inside of the lower inner cavity 10, and the other end is located outside the lower shell. In this embodiment, the lower cavity permeate outlet 6 is connected at the rear end face of the lower shell and can be coaxial with the lower cavity inner cavity 10. The lower inner cavity 10 is a cylindrical sealing space with a diameter of 30 mm and a depth of 20 mm, which collects the permeate. The lower shell concave hole plate groove 9 has a diameter of 40 mm and a depth of 3 mm, and is milled on the edge of the lower shell concave groove, which can exactly put the movable supporting hole plate 5. The lower shell concave groove shell-pressing outer sealing ring 4 with a central diameter of 45 mm is placed in the lower shell leakage-proof outer sealing concave groove 12, which is milled on the front end face of the lower shell and located at the periphery of the lower shell concave hole plate groove 9, and is used to prevent the feed liquid from leaking outward between the upper and lower shells.

[0039] Finally, the membrane assembly is fastened by stainless steel butterfly nut 7 (4 sets in total, each set containing gaskets) on four stainless steel screw rods 8. The whole assembly is shown in Figure 6 When the membrane is replaced, each stainless steel butterfly nut 7 is unscrewed, the upper and lower cavities are separated, the movable support hole plate 5 is removed, the replacement membrane is placed on the hole plate, the device is aligned and tightened, and the operation of replacing the membrane is simplified.

[0040] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, and are not limited thereto; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that the technical solutions described in the foregoing embodiments can still be modified, or some or all of the technical features can be replaced by equivalents; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A small-scale trial-and-error nanofiltration membrane module, characterized in that, include: A detachable stainless steel outer shell and a flat membrane core installed inside the outer shell, the outer shell comprising an upper shell and a lower shell, the upper shell and the lower shell being sealed together; The upper shell includes a feed inlet (1), a cross-flow outlet (2) set at an angle to the feed inlet (1), and an upper inner cavity (15). The upper inner cavity (15) is opened inside the upper shell. The feed inlet (1) is connected to the outer end of the upper shell along the axial direction. The cross-flow outlet (2) is connected to the side wall of the upper shell. The inner ends of the feed inlet (1) and the cross-flow outlet (2) are connected to the inside of the upper inner cavity (15). The feed inlet (1) is used by a high-pressure pump to pump feed liquid into the upper inner cavity (15), and the cross-flow outlet (2) is used to discharge concentrated liquid. The lower shell includes a lower inner cavity (10) opened inside the lower shell and a lower cavity permeate outlet (6) connected to the axial outer end of the lower shell. The flat membrane core includes a filter membrane installed between the lower inner cavity (10) and the upper inner cavity (15). The lower cavity permeate outlet (6) is connected to the interior of the lower inner cavity (10) and is used to collect the permeate or clear liquid passing through the filter membrane. The feed inlet (1) and the cross-flow outlet (2) are set at 90°; The upper and lower shells are respectively fitted with a nested inner seal and a leak-proof outer seal; The nested inner seal includes an upper shell nested inner seal protrusion (16) machined on the upper stainless steel upper shell through a milling groove. The upper shell nested inner seal protrusion (16) is filled with an upper shell protrusion pressure membrane inner seal ring (3) to prevent leakage from the inner side of the membrane. The leak-proof outer seal includes a lower shell leak-proof outer seal groove (12) machined by milling groove on the outer periphery of the stainless steel lower shell. The lower shell groove pressure outer seal ring (4) is filled in the lower shell leak-proof outer seal groove (12) to prevent the feed liquid from leaking out.

2. The small-scale cross-flow nanofiltration membrane module according to claim 1, characterized in that, A movable support plate (5) is provided between the lower inner cavity (10) and the upper inner cavity (15) to support the filter membrane.

3. The small-scale cross-flow nanofiltration membrane module according to claim 2, characterized in that, The sealing ring (3) inside the upper shell groove presses against the upper layer of the filter membrane placed on the movable support plate (5) to prevent the feed liquid from leaking into the lower cavity from the periphery side without passing through the membrane.

4. The small-scale cross-flow nanofiltration membrane module according to claim 2, characterized in that, The lower shell groove presses against the outer sealing ring (4) on the upper shell to prevent the feed liquid from leaking out.

5. According to claim 3, the movable support plate (5) is placed in the concave groove (9) of the lower shell processed on the lower shell, and the movable support plate (5), the concave groove (9) of the lower shell, the filter membrane, and the inner sealing ring (3) of the upper shell convex groove are coaxially arranged and their outer circumferential projections coincide.

6. The small-scale cross-flow nanofiltration membrane module according to claim 1, characterized in that, Both the upper and lower shells are disc-shaped structures. The upper shell has four through threaded holes on the circumferential direction near the outer edge of the disc, and the threaded holes are distributed on the outer side of the upper inner cavity (15). The lower shell has four through threaded holes on the circumferential direction near the outer edge of the disc, and they are distributed on the outer side of the lower inner cavity (10). The upper and lower threaded holes are coaxially arranged and fastened by stainless steel screw rods (8) and stainless steel wing nuts (7).

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