A secondary recovery system for chitosan material filter press filtrate

Abstract

This utility model discloses a secondary recovery system for hemicellulose filtrate from alkaline pressing, relating to the field of resource recycling technology. It includes a feed tank, a permeate tank, a CIP tank, and a membrane module. The feed tank has a feed pipe for conveying the alkaline pressing liquid, and both the feed tank and the CIP tank are connected to a pure water supply pipeline. The discharge pipes of the feed tank and the CIP tank are connected to the inlet of the membrane module via a first conveying pipeline. The clarified liquid outlet of the membrane module is connected to the permeate tank and the CIP tank, respectively, and the concentrated liquid outlet of the membrane module is connected to the feed tank and the CIP tank via a concentrated liquid conveying pipeline. A pure water conveying pipeline connects the pure water supply pipeline and the first conveying pipeline. This utility model uses nanofiltration to circulate and filter hemicellulose in the alkaline pressing liquid, enabling complete recovery and reuse of the hemicellulose, and the purified alkaline liquid obtained after filtration can also be recycled.

Description

Technical Field

[0001] This utility model relates to the field of resource recycling technology, and more specifically, to a secondary recovery system for filtrate from hemicellulose raw material pressure filtration. Background Technology

[0002] Hemicellulose is a naturally occurring polymer that is widely distributed globally. With energy resources becoming increasingly depleted and the greenhouse effect becoming more severe, the development and utilization of biomass is receiving more and more attention from humankind. However, there are still many challenges, especially in the comprehensive utilization of hemicellulose. Due to its inherent disadvantages, such as easy degradation and difficulty in separation, the utilization value of hemicellulose is often overlooked.

[0003] In the production of viscose fiber using chemical pulps (wood pulp, cotton pulp, straw pulp, reed pulp, and other plant cellulose), the first step in manufacturing viscose fiber is to treat the cellulose with an alkaline solution (impregnation, pressing). A high concentration of hemicellulose has an extremely adverse effect on the viscose fiber production process and the quality of the finished product. Therefore, it is necessary to dissolve the hemicellulose with an alkaline solution during the impregnation process to obtain high-strength cellulose. This process generates a large amount of high-concentration alkaline pressing liquor rich in hemicellulose.

[0004] The main components of alkaline pressing liquor are sodium hydroxide and hemicellulose. However, existing methods for treating alkaline pressing liquor mostly use filtration technology to separate hemicellulose from it. However, due to incomplete filtration, the hemicellulose in the alkaline pressing liquor is not fully recovered and utilized. Utility Model Content

[0005] The purpose of this invention is to provide a secondary recovery system for hemicellulose raw material filtration filtrate. By using nanofiltration to circulate and filter hemicellulose in alkaline pressing liquid, the hemicellulose in alkaline pressing liquid is completely recovered and reused, and the pure alkaline solution obtained after filtration can also be recovered and reused.

[0006] To achieve the purpose of this utility model, the technical solution adopted is as follows: a secondary recovery system for filtrate from hemicellulose raw material pressure filtration, comprising a feed tank, a permeate tank, a CIP tank, and a membrane module. The feed tank has a feed pipe for conveying alkaline pressing liquid, and both the feed tank and the CIP tank are connected to a pure water supply pipeline. The discharge pipes of the feed tank and the CIP tank are connected to the inlet of the membrane module through a first conveying pipeline. The clear liquid outlet of the membrane module is connected to the permeate tank and the CIP tank, respectively, and the concentrated liquid outlet of the membrane module is connected to the feed tank and the CIP tank through a concentrated liquid conveying pipeline. A pure water conveying pipeline is connected between the pure water supply pipeline and the first conveying pipeline.

[0007] Furthermore, there are multiple feed tanks and membrane modules, and these multiple feed tanks and membrane modules are arranged in parallel.

[0008] Furthermore, it also includes a cleaning solution preparation tank connected to the CIP tank, and the inlet of the cleaning solution preparation tank is connected to a pure water supply pipeline.

[0009] Furthermore, a material conveying pipe is connected in parallel to the discharge pipe of the feed tank, and a material conveying pump is installed on the material conveying pipe.

[0010] Furthermore, sampling valves are installed in both the concentrated liquid delivery pipeline and the clear liquid outlet of the membrane module.

[0011] Furthermore, a cleaning fluid delivery pipe is connected between the CIP tank and the first delivery pipeline, and a wastewater discharge pipe is also connected in parallel to the cleaning fluid delivery pipe.

[0012] Furthermore, a heat exchanger, a bag filter, a feed pump, and a booster pump are also installed on the conveying pipeline.

[0013] Furthermore, the heat exchanger's heat exchange medium inlet is also connected to a steam conveying pipeline and a cooling water return pipe, and the heat exchanger's heat exchange medium outlet is also connected to a cooling water supply pipe and a drain pipe.

[0014] The beneficial effects of this utility model are: In this invention, the alkali-pressed liquid in the feed tank is filtered through a membrane module, and the concentrated liquid after filtration is then returned to the feed tank, thus repeatedly circulating and filtering the alkali-pressed liquid. Simultaneously, when the concentration of the high-concentration alkali-pressed liquid in the feed tank is too high to filter out the alkali, pure water can be supplied to the feed tank to mix it with the high-concentration alkali-pressed liquid. This mixture is then filtered again through the membrane module, resulting in better recovery of hemicellulose and alkali.

[0015] Meanwhile, in this invention, the clarified liquid obtained by membrane filtration is sent to the permeate tank and the CIP tank, so that the filtered alkaline solution can be used as the permeate in the future. The alkaline solution entering the CIP tank can be used directly as a cleaning solution or mixed with pure water as a cleaning solution, so that the alkaline solution obtained by membrane filtration can be fully utilized. Attached Figure Description

[0016] The accompanying drawings illustrate exemplary embodiments of the present invention and, together with the description thereof, serve to explain the principles of the present invention. These drawings are included to provide a further understanding of the present invention and are incorporated in and constitute a part of this specification.

[0017] Figure 1 This is a system diagram of the semi-fiber raw material pressure filtration filtrate secondary recovery system provided by this utility model.

[0018] The attached diagram shows the markings and corresponding component names: 1. Feed tank, 2. Permeate tank, 3. CIP tank, 4. Membrane module, 5. Feed pipe, 6. Pure water supply line, 7. Conveying line 1, 8. Material conveying pipe, 9. Cleaning fluid conveying pipe, 10. Heat exchanger, 11. Bag filter, 12. Feed pump, 13. Booster pump, 14. Steam conveying line, 15. Cooling water return pipe, 16. Cooling water supply pipe, 17. Drain pipe, 18. Concentrate conveying line, 19. Pure water conveying line, 20. Cleaning fluid preparation tank, 21. Sampling valve, 22. Wastewater discharge pipe. Detailed Implementation

[0019] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are for illustrative purposes only and are not intended to limit the scope of the present invention. Furthermore, it should be noted that, for ease of description, only the parts relevant to the present invention are shown in the accompanying drawings.

[0020] It should be noted that, where there is no conflict, the embodiments and features described in these embodiments can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0021] like Figure 1 As shown, this utility model provides a secondary recovery system for hemicellulose raw material filter press filtrate, including a feed tank 1, a permeate tank 2, a CIP tank 3, and a membrane module 4. The feed tank 1 stores the alkaline press filtrate obtained after filtration by a filter press. The main components of this alkaline press filtrate are sodium hydroxide and hemicellulose. The permeate tank 2 stores the permeate, the CIP tank 3 stores the alkaline washing solution, and the membrane module 4 filters the alkaline press filtrate from the feed tank 1. The feed tank 1 has a feed pipe 5 at its upper part, which feeds the alkaline press filtrate obtained after filtration into the feed tank 1. Both the feed tank 1 and the CIP tank 3 are connected to a pure water supply pipeline 6, allowing pure water to be supplied to the feed tank 1 and the CIP tank 3 through the pure water supply pipeline 6.

[0022] The discharge pipes of feed tank 1 and CIP tank 3 are both connected to the inlet of membrane module 4 via conveying pipeline 7, allowing the alkali pressing liquid in feed tank 1 to be transported to membrane module 4 for filtration via conveying pipeline 7. The alkali cleaning liquid in CIP tank 3 can be sent into membrane module 4 for cleaning. The clear liquid outlet of membrane module 4 is connected to permeate tank 2 and CIP tank 3 respectively, allowing the pure alkali liquid obtained after filtration by membrane module 4 to be transported to permeate tank 2 for use as permeate, while the pure alkali liquid obtained after filtration by membrane module 4 is transported to CIP tank 3 for preparing cleaning liquid. The concentrated liquid outlet of membrane module 4 is connected to feed tank 1 and CIP tank 3 via concentrated liquid conveying pipeline 18, allowing the concentrated liquid obtained after filtration by membrane module 4 to be transported to feed tank 1 via conveying pipeline. The cleaning liquid in CIP tank 3 used to clean membrane module 4 is then returned to CIP tank 3.

[0023] In addition, the inlet of membrane module 4 and the concentrate outlet of membrane module 4 are connected by a connecting pipe, and a pure water supply pipe 19 is connected between the pure water supply pipe 6 and the delivery pipe 7, so that the pure water in the pure water supply pipe 6 can enter the feed tank 1 and CIP tank 3 through the pure water delivery pipe 19, the delivery pipe 7, and the connecting pipe, so that the delivery pipe 7 and the pipe used to connect the concentrate outlet of membrane module 4 with the feed tank 1 and CIP tank 3 can be cleaned.

[0024] In this invention, there can be multiple feed tanks 1 and membrane modules, and these multiple feed tanks 1 and membrane modules are arranged in parallel. That is, the feed pipes 5 on the multiple feed tanks 1 are connected in parallel, so that the alkali pressing liquid sent from the filter press can be sent into each feed tank 1 respectively. The multiple feed tanks 1 are connected to the pure water supply pipeline 6, so that the pure water in the pure water supply pipeline 6 can enter each feed tank 1 respectively. The outlet ends of the discharge pipes of the multiple feed tanks 1 are connected in parallel, so that the alkali pressing liquid in the multiple feed tanks 1 can be sent into the conveying pipeline 7. In order to facilitate the conveying of the concentrated liquid after filtration in each feed tank 1 to the next process, each of the discharge pipes on the multiple feed tanks 1 is connected to a material conveying pipe 8, and the outlet ends of the multiple material conveying pipes 8 are connected in parallel. At the same time, in order to enable the concentrated liquid after filtration by the membrane module 4 to enter each feed tank 1 respectively, the outlet end of the concentrated liquid conveying pipeline 18 is connected to each of the multiple feed tanks 1.

[0025] When there are multiple membrane modules 4, the inlets of multiple membrane modules 4 are simultaneously connected to the delivery pipeline 7, the clear liquid outlets of multiple membrane modules 4 are connected together and then connected to multiple feed tanks 1 and CIP tanks 3, the concentrated liquid outlets of multiple membrane modules 4 are connected together to the concentrated liquid delivery pipeline 18, and the inlet of each membrane module 4 is connected to the concentrated liquid outlet of that membrane module 4.

[0026] The semi-fiber raw material pressure filtration filtrate secondary recovery system provided by this utility model also includes a cleaning solution preparation tank 3 connected to the CIP tank 3. The cleaning solution preparation tank 3 is used to prepare the cleaning solution. A stirrer is installed inside the cleaning solution preparation tank 3. Both the stirrer and the cleaning solution preparation tank 3 are made of 304 stainless steel, and the inlet of the cleaning solution preparation tank 3 is connected to the pure water supply pipeline 6. When cleaning solution needs to be prepared, pure water is delivered to the cleaning solution preparation tank 3 for preparation. In order to facilitate the delivery of the cleaning solution prepared in the cleaning solution preparation tank 3 into the CIP tank 3, a mixing pump is also installed on the pipeline connecting the CIP tank 3 and the cleaning solution preparation tank 3.

[0027] To facilitate the transport of high-content hemicellulose from feed tank 1 to the next process, a material conveying pipe 8 is connected in parallel to the discharge pipe of feed tank 1, and the outlet ends of multiple material conveying pipes 8 are interconnected. To further facilitate the transport of high-content hemicellulose from feed tank 1, a material conveying pump is installed at the interconnected outlet ends of the multiple material conveying pipes 8. The high-content hemicellulose from feed tank 1 is transported to the next process by the pump. To facilitate control of the transport of high-content hemicellulose in each feed tank 1, a switch valve is installed on each material conveying pipe 8.

[0028] To facilitate sampling and analysis of the filtered clear liquid and concentrated liquid, sampling valves 21 are installed on the pipeline connecting the clear liquid outlets of multiple membrane modules 4, and sampling valves 21 are also installed on the concentrated liquid delivery pipeline 18 connecting the concentrated liquid outlets of multiple membrane modules 4. The sampling valves 21 can be used to sample the clear liquid or concentrated liquid after filtration by the membrane modules 4, thereby facilitating the sampling and analysis of the filtered clear liquid and concentrated liquid.

[0029] To facilitate cleaning of membrane module 4, a cleaning solution delivery pipe 9 is connected between CIP tank 3 and delivery pipeline 7. This allows the cleaning solution in CIP tank 3 to be delivered to delivery pipeline 7 via the cleaning solution delivery pipe 9, and then to membrane module 4 via delivery pipeline 7, enabling the cleaning solution in CIP tank 3 to enter and clean the membrane module 4. To facilitate the discharge of the clarified and concentrated solutions after cleaning membrane module 4, a drain pipe is connected in parallel to the concentrated solution delivery pipeline 18, and drain pipes are also connected in parallel to the pipes connecting membrane module 4 to permeate tank 2 and CIP tank 3.

[0030] In this invention, a heat exchanger 10, a bag filter 11, a feed pump 12, and a booster pump 13 are also installed on the conveying pipeline 7. The heat exchanger 10, bag filter 11, feed pump 12, and booster pump 13 are all located downstream of the cleaning liquid conveying pipeline 9, allowing the alkali pressing liquid and cleaning liquid conveyed through the conveying pipeline 7 to be heated or cooled by the heat exchanger 10. This facilitates the subsequent filtration of the membrane module 4 and the cleaning of the membrane module 4 by the cleaning liquid. Two bag filters 11 can be used, arranged in parallel on the conveying pipeline 7. During system operation, only one bag filter 11 can operate, with the other serving as a backup. To facilitate control of the bag filter 11's operation, on / off valves are installed at both the inlet and outlet ends of the bag filter 11. On the conveying pipeline 7, the booster pump 13 is located at the output end of the feed pump 12, so that the alkali pressing liquid and washing liquid sent by the feed pump 12 can be pressurized by the booster pump 13, thereby ensuring that they enter the membrane module 4 for filtration or for cleaning the membrane module 4.

[0031] Of course, in this invention, a temperature sensor, a pressure sensor, a feed flow meter, and a conductivity sensor can also be installed on the conveying pipeline 7, and these sensors are all located between the feed pump 12 and the bag filter 11. Alternatively, a pressure sensor, a temperature sensor, a pressure gauge, and a conveying pump can also be installed at the inlet end of the heat exchanger 10. In this invention, a conveying pump can be selected to be installed on the corresponding pipeline according to the conveying requirements.

[0032] In this invention, to facilitate the supply of cooling or heating media to the heat exchanger 10, the heat exchange medium inlet of the heat exchanger 10 is also connected to the steam conveying pipeline 14 and the cooling water return pipe 15, and the heat exchange medium outlet of the heat exchanger 10 is also connected to the cooling water supply pipe 16 and the drain pipe 17; when it is necessary to heat the alkali pressing liquid or washing liquid passing through the heat exchanger 10, the steam conveying pipeline 14 delivers low-pressure steam into the heat exchanger 10, which then enters the heat exchanger 10. Low-pressure steam exchanges heat with the alkali pressing liquid or cleaning liquid, heating the alkali pressing liquid or cleaning liquid. The condensate formed after the heat exchange is sent out through the drain pipe 17. When it is necessary to cool down the alkali pressing liquid or cleaning liquid, the cooling water supply pipe 16 delivers cooling water to the heat exchanger 10. The cooling water entering the heat exchanger 10 exchanges heat with the alkali pressing liquid or cleaning liquid, cooling the alkali pressing liquid or cleaning liquid. The cooling water after the heat exchange is recycled through the cooling water return pipe 15.

[0033] When this invention is in operation, if it is necessary to recover hemicellulose from the alkali pressing liquid, the alkali pressing liquid entering the feed tank 1 is transported to each membrane module 4 through the conveying pipeline 7. The alkali pressing liquid is filtered through each membrane module 4. The concentrated liquid after filtration through the membrane module 4 is transported back to the feed tank 1 through the concentrated liquid conveying pipeline 18. The clear liquid after filtration through the membrane module 4 is sent to the permeate tank 2 for use as permeate, or the clear liquid after filtration through the membrane module 4 is sent to the CIP tank 3 for use as cleaning liquid.

[0034] When membrane module 4 needs to be cleaned, the alkaline solution recovered in CIP tank 3 or the cleaning solution prepared by cleaning solution preparation tank 3 is transported to each membrane module 4 through the delivery pipeline 7. The cleaning solution cleans each membrane module 4. After cleaning each membrane module 4, the clear liquid or concentrated liquid discharged through the membrane module 4 can be directly discharged to the sewage treatment process through the drain pipe.

[0035] Those skilled in the art should understand that the above embodiments are merely for clearly illustrating the present invention and are not intended to limit the scope of the present invention. Those skilled in the art can make other changes or modifications based on the above disclosure, and these changes or modifications still fall within the scope of the present invention.

Claims

1. A secondary recovery system for hemicellulose raw material pressure filtration filtrate, characterized in that, The system includes a feed tank (1), a permeate tank (2), a CIP tank (3), and a membrane module (4). The feed tank (1) has a feed pipe (5) for conveying alkaline pressing liquid, and both the feed tank (1) and the CIP tank (3) are connected to a pure water supply pipeline (6). The discharge pipes of the feed tank (1) and the CIP tank (3) are connected to the inlet of the membrane module (4) through a first conveying pipeline (7). The clear liquid outlet of the membrane module (4) is connected to the permeate tank (2) and the CIP tank (3) respectively, and the concentrated liquid outlet of the membrane module (4) is connected to the feed tank (1) and the CIP tank (3) through a concentrated liquid conveying pipeline (18). A pure water conveying pipeline (19) is connected between the pure water supply pipeline (6) and the first conveying pipeline (7).

2. The hemicellulose raw material pressure filtration filtrate secondary recovery system according to claim 1, characterized in that, There are multiple feed tanks (1) and membrane modules (4), and the multiple feed tanks (1) and multiple membrane modules (4) are arranged in parallel.

3. The hemicellulose raw material pressure filtration filtrate secondary recovery system according to claim 1, characterized in that, It also includes a cleaning solution preparation tank (20) connected to the CIP tank (3), and the inlet of the cleaning solution preparation tank (20) is connected to the pure water supply pipeline (6).

4. The hemicellulose raw material pressure filtration filtrate secondary recovery system according to claim 1, characterized in that, The feed tank (1) is connected in parallel to the discharge pipe of the feed tank (1), and a material conveying pipe (8) is also installed on the material conveying pipe (8).

5. The hemicellulose raw material pressure filtration filtrate secondary recovery system according to claim 1, characterized in that, Both the concentrated liquid delivery pipeline (18) and the clear liquid outlet of the membrane module (4) are equipped with sampling valves (21).

6. The hemicellulose raw material pressure filtration filtrate secondary recovery system according to claim 1, characterized in that, A cleaning fluid delivery pipe (9) is also connected between the CIP tank (3) and the delivery pipeline (7), and a wastewater discharge pipe (22) is also connected in parallel to the cleaning fluid delivery pipe (9).

7. The hemicellulose raw material pressure filtration filtrate secondary recovery system according to any one of claims 1 to 6, characterized in that, The conveying pipeline (7) is also equipped with a heat exchanger (10), a bag filter (11), a feed pump (12) and a booster pump (13).

8. The hemicellulose raw material pressure filtration filtrate secondary recovery system according to claim 7, characterized in that, The heat exchanger (10) is connected to a steam conveying pipeline (14) and a cooling water return pipe (15) at the heat exchange medium inlet, and to a cooling water supply pipe (16) and a drain pipe (17) at the heat exchanger (10).

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