A continuous filtration process for beer

Abstract

A continuous beer filtration process comprises the following steps: 1. Pre-coating: Prepare at least two filter groups, namely Group 1 and Group 2. The filter element of Group 1 is pre-coated with a PVPP filter layer; 2. Filtration: Input the beer to be filtered and the PVPP dispersion into Group 1 for filtration; 3. Switching: When the filtration capacity of Group 1 is about to reach saturation, input the beer to be filtered and the PVPP dispersion into Group 2. Beer output from Group 2 is then input into Group 1 for filtration, and the filtered beer is output from Group 1; 4. Regeneration: When the filtration capacity of Group 2 stabilizes, input the beer to be filtered and the PVPP dispersion into Group 2 for filtration. The filtered beer is output from Group 2, and Group 1 undergoes PVPP regeneration. The regenerated PVPP is collected in a PVPP storage tank. This invention enables continuous beer filtration, improves filtration efficiency, and simultaneously achieves PVPP regeneration.

Description

Technical Field

[0001] This invention belongs to the field of beer processing technology, specifically relating to a continuous filtration process for beer. Background Technology

[0002] The synthesis of PVP (polyvinylpyrrolidone) can be traced back to 1939. It is soluble in water and most organic solvents, exhibiting excellent complexing ability and colloidal properties. However, its solubility limits its development and application. Based on this, its derivative, PVPP (cross-linked polyvinylpyrrolidone), was developed. In addition to its excellent adsorption capacity, PVPP is safe, stable, non-toxic, and non-irritating, and is widely used in medical, chemical, and beverage industries.

[0003] Mature beer accumulates a large amount of polyphenols due to the raw materials themselves and after fermentation. These polyphenols combine with proteins to form colloidal complexes, causing beer turbidity. Even if this turbidity is removed through filtration, the free polyphenols dissolved in the beer will combine with proteins under the influence of oxygen to produce new turbidity, reducing the beer's non-biological stability. This process is irreversible. Therefore, it is necessary to filter soluble polyphenols in beer, and PVPP, with its excellent polyphenol adsorption capacity, is used in the beer filtration stage.

[0004] PVPP can be divided into single-use and recyclable types. Single-use PVPP is generally used by enterprises with small production volumes. It is simple to operate and does not require expensive recycling equipment, but it also has problems such as increased long-term production investment, waste, and uneven distribution.

[0005] The adsorption capacity of regenerable PVPP polyphenols will reach saturation after a period of production, and its polyphenol adsorption capacity will decrease, so it needs to be regenerated.

[0006] Currently, horizontal disc PVPP filters and candle PVPP filters are important equipment in industrial beer filtration production. When PVPP is regenerated, the entire filtration process must be interrupted. After the PVPP undergoes alkali and acid treatment for regeneration, it is flushed back into the PVPP mixing tank with deoxygenated water for reconfiguration to replenish the lost PVPP before filtration production can resume. PVPP regeneration is a lengthy process, significantly impacting the filtration efficiency of beer production. Summary of the Invention

[0007] The technical problem to be solved by the present invention is to provide a continuous filtration process for beer, which can continuously filter beer, improve filtration efficiency, and achieve PVPP regeneration, in light of the current state of the technology.

[0008] The technical solution adopted by this invention to solve the above-mentioned technical problems is: a continuous filtration process for beer, characterized by the following steps:

[0009] 1. Pre-coating: Prepare at least two filter sets, namely set one and set two. The filter element of set one is pre-coated with PVPP filter layer. At this time, set one is in working state and set two is in standby state.

[0010] 2. Filtration: The beer to be filtered and the PVPP dispersion are fed into Group 1 in working condition for filtration. The filtered beer is output from Group 1.

[0011] 3. Switching: When the filtration capacity of Group 1 is about to reach saturation, the beer to be filtered and the PVPP dispersion are first fed into Group 2 in standby state so that the PVPP particles in the dispersion can adhere to the filter surface of the filter element of Group 2 and achieve filtration. The beer output from Group 2 is fed into Group 1 for filtration, and the filtered beer is output from Group 1.

[0012] IV. Regeneration: Once the filtration capacity of Group 2 stabilizes (as the beer to be filtered and the PVPP dispersion are continuously fed into Group 2 in the standby state, the number of PVPP particles attached to the filter surface of Group 2 increases, forming a PVPP filter layer, similar to the pre-coating effect in Step 1, thus stabilizing the filtration capacity of Group 2), Group 2 is in working condition. The beer to be filtered and the PVPP dispersion are fed into Group 2 for filtration. The filtered beer is output from Group 2, and Group 1 undergoes PVPP regeneration. The regenerated PVPP is collected in the PVPP storage tank, and Group 1 is in standby condition.

[0013] The process of this invention enables continuous beer filtration without downtime, and the PVPP can be regenerated when the filtration capacity reaches saturation without affecting the normal filtration operation of other filtration units. Furthermore, the design of step three in this invention ensures a longer contact time between PVPP and polyphenols in the beer during the switching process between the working and standby filtration units, resulting in better polyphenol adsorption. The entire process is free of beer loss, and the PVPP filter layer adhering to the filter element is more uniform, thereby improving filtration efficiency.

[0014] Preferably, the filter assembly includes a housing and a wedge-shaped wire screen cylinder disposed within the housing, wherein the wedge-shaped wire screen cylinder is the filter element described above. Of course, the filter assembly of the present invention can also employ other existing structures, such as a candle filter structure.

[0015] Preferably, in step four, the step of regenerating PVPP in group one is as follows:

[0016] 1) Bring brewing water at a temperature >80℃ into Group 1 for rinsing, and then output the wastewater from Group 1.

[0017] (ii) Add alkali to brewing water at >80℃, and then repeat the process of entering and exiting group one to perform alkali circulation;

[0018] (iii) After the alkali cycle is completed, brewing water at >80℃ is introduced into Group 1 for rinsing. The rinsing wastewater is discharged from Group 1 to drain the alkali solution in Group 1.

[0019] (iv) Add acid to brewing water at >80℃, and then repeat the process of entering and exiting group one to perform acid circulation;

[0020] (v) After the acid cycle is completed, brewing water at >80℃ is introduced into Group 1 for rinsing. The rinsing wastewater is discharged from Group 1 to drain the acid liquid in Group 1.

[0021] After hot water rinsing, alkaline circulation, and acid circulation, PVPP can be effectively regenerated, and the loss of PVPP can be reduced.

[0022] Preferably, in steps one), three), and five), the method for rinsing the brewing water is as follows:

[0023] First, brewing water at temperatures above 80°C is introduced into Group 1 for rinsing. After rinsing, the wastewater is discharged. Then, the brewing water at temperatures above 80°C is repeatedly introduced into and out of Group 1 for hot water circulation.

[0024] Furthermore, the acid cycle and / or base cycle time is 30 min.

[0025] In the above scheme, preferably, the filter group has an inlet for inputting the beer to be filtered and the PVPP dispersion, and an outlet for outputting the filtered beer.

[0026] In step four, the process of collecting the regenerated PVPP into the PVPP storage tank is as follows:

[0027] Deoxygenated water is introduced into Group 1 through the outlet to backflush the regenerated PVPP in Group 1 into the PVPP storage tank through the inlet. Then, carbon dioxide gas is introduced into Group 1 through the outlet to compress the deoxygenated water in Group 1 into the PVPP storage tank through the inlet. This process of backflushing with deoxygenated water followed by compressing with carbon dioxide gas ensures that all the regenerated PVPP in Group 1 is collected into the PVPP storage tank, further reducing PVPP loss.

[0028] Preferably, the step of collecting the regenerated PVPP into the PVPP storage tank can be selectively repeated, and finally the first group is filled with deoxygenated water, so that the first group is filled with deoxygenated water.

[0029] Furthermore, in step three, when the filtration capacity of group one in the working state is about to reach saturation, the beer to be filtered and the PVPP dispersion are first fed into group two to push out the deoxygenated water in group two and discharge the wastewater. The beer output from group two is fed into group one for filtration, and the filtered beer is output from group one.

[0030] Compared with existing technologies, the advantages of this invention are as follows: The process of this invention enables continuous beer filtration without downtime, and the PVPP can be regenerated from the filtration unit that has reached saturation without affecting the normal filtration operation of other filtration units. Furthermore, the design of step three in this invention ensures a longer contact time between PVPP and polyphenols in the beer during the switching process between the working and standby filtration units, resulting in better polyphenol adsorption. The entire process is free of beer loss, and the PVPP filter layer adhering to the filter element is more uniform, thereby improving filtration efficiency. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of the system structure according to an embodiment of the present invention. Detailed Implementation

[0032] like Figure 1 As shown, this is a preferred embodiment of a continuous filtration process for beer according to the present invention. The continuous filtration process in this embodiment adopts a continuous filtration system, which includes a filter group 1, a feed pipeline 2, a discharge pipeline 3, an intermediate pipeline 4, a sewage discharge pipeline 5, a cleaning pipeline 6, a deoxygenated water pipeline 7, a PVPP storage tank 8, and a gas pipeline 9.

[0033] There are at least two filter groups 1 (four in this embodiment). Each filter group 1 has a housing 10 with an inlet 11 and an outlet 12, and a filter element 13 disposed within the housing 10. The filter element 13 is a conventional wedge-shaped wire screen, and the wall of the screen has a filter surface that allows PVPP to adhere. When the PVPP mixture enters the filter element 13, the PVPP particles can adhere to the filter surface to form a PVPP layer. The PVPP layer can filter soluble polyphenols in the beer that has passed through the filter surface. The outlet 12 of each filter group 1 is connected to the inlet 11 of other filter groups 1 through an intermediate pipeline 4, and each intermediate pipeline 4 is equipped with a third valve for controlling the flow rate.

[0034] The feed line 2 is used to transport the beer to be filtered and the PVPP mixture. The beer to be filtered enters the feed line 2 through the beer line. The outlet end of the PVPP storage tank 8 containing the PVPP mixture is connected to the feed line 2 so that the beer to be filtered and the PVPP mixture can enter the feed line 2. The output end of the feed line 2 is connected to the inlet 11 of each filter group 1 through their respective first lines 21, and each first line 21 is equipped with a first valve for controlling the flow rate.

[0035] The discharge pipeline 3 is used to transport filtered beer downstream. The input end of the discharge pipeline 3 is connected to the outlet 12 of each filter group 1 through their respective second pipelines 31, and each second pipeline 31 is equipped with a second valve for controlling the flow rate.

[0036] In this embodiment, the first valve is an existing double-seat valve. There are four first valves, designated as Double-Seat Valve 1 211, Double-Seat Valve 212, Double-Seat Valve 3 213, and Double-Seat Valve 4 214, respectively. Each first valve is sequentially installed on the feed line 2 and connected to the end of its corresponding first line 21. The second valve is also an existing double-seat valve. There are four second valves, designated as Double-Seat Valve 5 311, Double-Seat Valve 6 312, Double-Seat Valve 7 313, and Double-Seat Valve 8 314, respectively. Each second valve is sequentially installed on the discharge line 3 and connected to the end of its corresponding second line 31. The input end of the discharge line 3 is connected to the output end of the feed line 2, and a first butterfly valve 401 is provided at the connection point as a switching element.

[0037] The cleaning pipeline 6 is used to transport cleaning liquid (in this embodiment, brewing water, acidic brewing water, and alkaline brewing water are the cleaning liquid). The input end of the cleaning pipeline 6 is connected to an alkali supply pipeline 62 for supplying alkali, an acid supply pipeline 63 for supplying acid, and a water supply pipeline 64 for supplying brewing water. Each of the alkali supply pipeline 62, acid supply pipeline 63, and water supply pipeline 64 is equipped with a valve for controlling the flow rate. Specifically, the alkali supply pipeline 62 is equipped with a fifteenth butterfly valve 415 and a fourteenth butterfly valve 414, and an alkali supply pump; the acid supply pipeline 63 is equipped with a sixteenth butterfly valve 416 and the aforementioned fourteenth butterfly valve 414, and an acid supply pump; the water supply pipeline 64 is equipped with a seventeenth butterfly valve 417 and a nineteenth butterfly valve 419, and a hot water supply pump. The output end of the cleaning pipeline 6 is connected to the inlet 11 of each filter group 1, and the cleaning pipeline 6 is equipped with a fourth valve for controlling the flow rate. In this embodiment, the fourth valve is an existing double-seat valve. There are four fourth valves, which are respectively labeled as double-seat valve A 611, double-seat valve B 612, double-seat valve C 613, and double-seat valve D 614. Each of the fourth valves is sequentially installed on the cleaning pipeline 6. Double-seat valve A 611 is connected to double-seat valve one 211 through a pipeline, double-seat valve B 612 is connected to double-seat valve two 212 through a pipeline, double-seat valve C 613 is connected to double-seat valve three 213 through a pipeline, and double-seat valve D 614 is connected to double-seat valve four 214 through a pipeline.

[0038] The inlet of the sewage pipeline 5 is connected to the outlet 12 of each filter group 1, and the outlet of the sewage pipeline 5 is connected to the downstream. The sewage pipeline 5 is equipped with a fifth valve for controlling the flow rate, a sewage valve 53 (an existing butterfly valve), and a regulating valve for controlling the pipeline pressure. There are two regulating valves, namely a first regulating valve 51 and a second regulating valve 52, which are connected in parallel. In this embodiment, the inlet of the sewage pipeline 5 is connected to the outlet of the cleaning pipeline 6. The connection point is the aforementioned intermediate pipeline 4, and a third butterfly valve 403 is provided at the connection point as the third valve. Meanwhile, there are four fifth valves on the sewage pipeline 5: double-seat valve E511, double-seat valve F512, double-seat valve G513, and double-seat valve H514. Double-seat valve E511 is connected to double-seat valve F512 via a pipeline, double-seat valve F512 is connected to double-seat valve G513 via a pipeline, double-seat valve G513 is connected to double-seat valve H514 via a pipeline, and double-seat valve H514 is connected to double-seat valve H8 via a pipeline. In this embodiment, the cleaning pipeline 6 is equipped with a second butterfly valve 402 as a switching element, and the sewage pipeline 5 is equipped with a fourth butterfly valve 404 as a switching element. The second butterfly valve 402 and the fourth butterfly valve 404 are located on both sides of the double-seat valves A through H as a whole.

[0039] Meanwhile, the input end of the cleaning pipeline 6 is connected to the sewage pipeline 5 to form a loop (the output end of the sewage pipeline, as well as the sewage valve 53 and regulating valve 51, are located outside the loop; a twentieth butterfly valve 420 is provided at the connection between the input end of the cleaning pipeline 6 and the sewage pipeline 5 as a switching element), and a circulation pump 61 is provided on the cleaning pipeline 6. In this embodiment, the circulation pump 61 is located close to the input end of the cleaning pipeline 6. Simultaneously, a thermometer 54 for detecting the temperature of the medium within the loop and a conductivity meter 55 for detecting the conductivity of the medium within the loop are provided on the sewage pipeline.

[0040] The deoxygenated water pipeline 7, used for conveying deoxygenated water, is connected to the cleaning pipeline 6 via a double-seat valve K 71, enabling deoxygenated water supply and deoxygenated water return.

[0041] Gas pipeline 9 is used to transport carbon dioxide gas. The first output end of gas pipeline 9 is connected to the inlet of PVPP storage tank 8, and the second output end of gas pipeline 9 is connected to the outlet 12 of each filter group 1. In this embodiment, the second output end of gas pipeline 9 is connected to sewage pipeline 5. Furthermore, a twenty-second butterfly valve 422 and a twenty-third butterfly valve 423 are provided on gas pipeline 9 near its second output end as switching devices.

[0042] Meanwhile, the inlet 11 of each filter group 1 is connected to the inlet end of the PVPP storage tank 8 via the third pipeline 81. Specifically, the first end of the third pipeline 81 is connected to the inlet end of the PVPP storage tank 8, and the second end is connected to the aforementioned cleaning pipeline 6. The third pipeline 81 is equipped with a fifth butterfly valve 405 and a thirteenth butterfly valve 413 as switching devices. The fifth butterfly valve 405 is located near the second end of the third pipeline 81, and the thirteenth butterfly valve 413 is located near the first end of the third pipeline 81. The cleaning pipeline 6, located upstream of the second end of the third pipeline 81, is equipped with a sixth butterfly valve 406, a seventh butterfly valve 407, and an eighth butterfly valve 408 as switching devices. Simultaneously, the cleaning pipeline 6, located between the seventh butterfly valve 407 and the eighth butterfly valve 408, is connected to the sewage pipeline 5 via a pipeline, and a ninth butterfly valve 409 is installed on this pipeline as a switching device. The sewage pipeline 5 is equipped with a tenth butterfly valve 410 as a switching device.

[0043] In this embodiment, the first pipeline 21 and the second pipeline 31 are connected to the feed pipeline 2, the discharge pipeline 3, the intermediate pipeline 4, the sewage discharge pipeline 5, and the cleaning pipeline 6 via a valve array equipped with the aforementioned first, second, third, fourth, and fifth valves. By controlling the valve array, the flow direction of the fluid can be controlled, facilitating operation. Furthermore, each filter group is only connected to the first pipeline 21 and the second pipeline 31, reducing the number of pipelines directly connected to the filter group.

[0044] The filtration process requirements for this embodiment are as follows:

[0045] 1. Number the four filter groups in this embodiment, such as... Figure 1 As shown, from left to right, they are group 1, group 2, group 3, and group 4.

[0046] 2. PVPP pre-coating: Pre-coat the filter elements 13 of Group 1, Group 2, and Group 3 with PVPP layer. Group 4 is left idle and filled with deoxygenated water.

[0047] 3. Filtration: Beer processed by the soilless filter at the front end enters the filtration system and enters Group 1, Group 2 and Group 3 together with the PVPP dispersion output from PVPP storage tank 8 for filtration. The filtered beer is then output to the downstream buffer tank through discharge pipeline 3.

[0048] 4. When the filtration capacity of Group 1 is about to reach saturation, activate Group 4. The specific operation procedure is as follows:

[0049] (1) Open the double-seat valve 214 for beer feeding in group four and the double-seat valve H 514, fourth butterfly valve 404, tenth butterfly valve 410, sewage valve 53, and first regulating valve 51 on the sewage line 5, so that the beer and PVPP mixture in the feed line 2 enter group four, and push out the deoxygenated water in group four through the sewage line 5 (i.e. beer top deoxygenated water). After the beer top deoxygenated water is finished, close the fourth butterfly valve 404.

[0050] (2) After the deoxygenation of Group 4 beer is completed, the double-seat valve 214 for beer inlet and the double-seat valve H514 on the sewage line 5 continue to be opened, and the third butterfly valve 403 is opened. The double-seat valve 211 for beer inlet of Group 1 is closed, and the double-seat valve A 611 and the double-seat valve 311 are opened, so that the beer and PVPP mixture in the feed line 2 first enter Group 4 (so that the PVPP particles in the dispersion adhere to the filter element of Group 4 to achieve the pre-coating effect), and then enter Group 1 for filtration. The beer filtered by Group 1 is output to the downstream buffer tank through the discharge line 3.

[0051] (3) When the filtration capacity of Group 4 is stable, close the double-seat valve H 514 and open the double-seat valve 8 314 for beer dispensing. Group 4 will start filtering beer normally. At the same time, close the third butterfly valve 403 and open the double-seat valve K 71, the second butterfly valve 402, the sixth butterfly valve 406, the seventh butterfly valve 407, and the eighth butterfly valve 408. Deoxygenated water enters Group 1 through the cleaning pipeline to push out the beer in Group 1 (i.e., deoxygenated water pushes out the beer). The pushed-out beer is discharged to the downstream buffer tank through the discharge pipeline 3.

[0052] (4) After Group 1 has completed the deoxygenation and top-drinking process, close the double-seat valve 311 used for discharging alcohol from Group 1. Groups 2, 3, and 4 maintain normal PVPP filtration production and begin PVPP regeneration for Group 1.

[0053] 5. The PVPP regeneration process for Group 1 is as follows:

[0054] (1) Open the double-seat valve A 611, double-seat valve E 511, second butterfly valve 402, fourth butterfly valve 404, sixth butterfly valve 406, seventh butterfly valve 407, eighth butterfly valve 408, tenth butterfly valve 410, drain valve 53, and second regulating valve 52 corresponding to Group 1. Turn on the seventeenth butterfly valve 417, nineteenth butterfly valve 419 and hot water supply pump for hot water (hot water is brewing water above 80℃). Turn on the circulation pump 61. Hot water is transported to Group 1 for cleaning through the cleaning pipeline. The cleaned hot water is discharged through the drain pipeline. After the hot water has been cleaning for a period of time, close the drain valve 53 and second regulating valve 52. Close the seventeenth butterfly valve 417, nineteenth butterfly valve 419 and hot water supply pump for hot water supply. Open the twentieth butterfly valve 420 to start hot water circulation (hot water flows in the loop).

[0055] (2) Open the fourteenth butterfly valve 414, the fifteenth butterfly valve 415 and the alkali supply pump to allow alkali to enter the hot water. When the conductivity meter 55 measures the alkali conductivity value to reach the PVPP regeneration set value of 80ms, close the fourteenth butterfly valve 414, the fifteenth butterfly valve 415 and the alkali supply pump to circulate the hot water with alkali.

[0056] (3) After the cycle, if the conductivity value measured by the conductivity meter 55 drops below the PVPP regeneration value, then continue step (2) until the conductivity is qualified and stable.

[0057] (4) When the alkali conductivity measured by the conductivity meter 55 and the value displayed by the thermometer 54 reach the cleaning set value, the alkali circulation is started and the circulation time is set to 30 minutes. The pressure in the loop during circulation is designed according to the pipe diameter and filter material to achieve the cleaning effect.

[0058] (5) After the alkali circulation ends, open the seventeenth butterfly valve 417, the nineteenth butterfly valve 419 and the hot water supply pump for hot water supply, close the twentieth butterfly valve 420, open the drain valve 53 and the second regulating valve 52, use hot water to push out the alkali solution in group one and drain it through the drain pipeline until the alkali conductivity measured by the conductivity meter 55 drops to 0ms, then close the drain valve 53 and the second regulating valve 52, close the seventeenth butterfly valve 417 and the nineteenth butterfly valve 419 and the hot water supply pump for hot water supply, open the twentieth butterfly valve 420 and start the hot water circulation;

[0059] (6) Open the fourteenth butterfly valve 414, the sixteenth butterfly valve 416 and the acid supply pump to allow acid to enter the hot water. When the conductivity meter 55 measures the acid conductivity value to reach the value set for PVPP regeneration for 15ms, close the fourteenth butterfly valve 414, the sixteenth butterfly valve 416 and the acid supply pump to circulate the hot water with acid.

[0060] (7) After the cycle, if the acid conductivity value measured by the conductivity meter 55 drops below the PVPP regeneration value, then continue with step (6) until the acid conductivity is qualified and stable.

[0061] (8) When the acid conductivity measured by the conductivity meter 55 and the value displayed by the thermometer 54 reach the cleaning set value, acid circulation is started and the circulation time is set to 30 minutes.

[0062] (9) After the acid cycle ends, open the seventeenth butterfly valve 417, the nineteenth butterfly valve 419 and the hot water supply pump for hot water supply, close the twentieth butterfly valve 420, open the drain valve 53 and the second regulating valve 52, and use hot water to push out and drain the acid in group one until the conductivity meter 55 shows a drop to 0ms. Then close all valves and pumps on the cleaning pipeline and the drain pipeline. The PVPP regeneration ends.

[0063] 6. Open the double-seat valve K 71 for deoxygenated water supply, the double-seat valves A 611 and E 511 corresponding to Group 1, as well as the eighth butterfly valve 408, the ninth butterfly valve 409, the tenth butterfly valve 410, the fourth butterfly valve 404, the second butterfly valve 402, the fifth butterfly valve 405, and the thirteenth butterfly valve 413 to start backflushing Group 1 with deoxygenated water (i.e., deoxygenated water enters Group 1 from outlet 12 and exits from inlet 11), backflushing the regenerated PVPP in Group 1 back to make it flow back to the PVPP storage tank 8;

[0064] Then close the double-seat valve K 71, the eighth butterfly valve 408, the ninth butterfly valve 409, and the tenth butterfly valve 410 for the deoxygenated water supply. Next, open the twenty-second butterfly valve 422 and the twenty-third butterfly valve 423 to use carbon dioxide gas to compress the deoxygenated water-PVPP mixture in Group 1 to the PVPP storage tank (similarly, carbon dioxide gas enters Group 1 from outlet 12 and exits from inlet 11). Then close the twenty-second butterfly valve 422 and the twenty-third butterfly valve 423.

[0065] Next, open the double-seat valve K 71, the eighth butterfly valve 408, the ninth butterfly valve 409, and the tenth butterfly valve 410 for the deoxygenated water supply. The deoxygenated water will flush the wedge wire screen in the filter group through the rotating washing ball. After flushing, repeat the above operations of backflushing group one with deoxygenated water and compressing carbon dioxide gas. Finally, refill group one with deoxygenated water and then close all the valves used above.

[0066] 7. Group 1 has now completed the entire PVPP regeneration process.

[0067] 8. Similarly, the same process can be used for PVPP regeneration in Groups 2 and 3.

[0068] The filtration system of this invention can regenerate PVPP without interrupting filtration. During filtration, the PVPP has a long contact time with the polyphenols in the beer, resulting in greater polyphenol adsorption and a more uniform PVPP layer formed in the wedge-shaped wire screen cylinder. The entire process is beer-free. After PVPP regeneration, all the regenerated PVPP can be backflushed back into the PVPP storage tank, achieving zero PVPP discharge and reducing PVPP loss. Simultaneously, pressure control via the regulating valve prevents PVPP layer collapse.

Claims

1. A continuous filtration process for beer, characterized in that... The steps are as follows:

1. Pre-coating: Prepare at least two filter sets, namely set one and set two. The filter element of set one is pre-coated with PVPP filter layer. At this time, set one is in working state and set two is in standby state.

2. Filtration: The beer to be filtered and the PVPP dispersion are fed into Group 1 in working condition for filtration. The filtered beer is output from Group 1.

3. Switching: When the filtration capacity of Group 1 is about to reach saturation, the beer to be filtered and the PVPP dispersion are first fed into Group 2 in standby state so that the PVPP particles in the dispersion can adhere to the filter surface of the filter element of Group 2 and achieve filtration. The beer output from Group 2 is fed into Group 1 for filtration, and the filtered beer is output from Group 1. IV. Regeneration: Once the filtration capacity of Group 2 is stable, Group 2 is in working condition. The beer to be filtered and the PVPP dispersion are fed into Group 2 for filtration. The filtered beer is output from Group 2, and Group 1 is regenerated. The regenerated PVPP is collected in the PVPP storage tank. At this time, Group 1 is in standby condition.

2. The continuous filtration process according to claim 1, characterized in that: The filter assembly includes a housing and a wedge-shaped wire screen cylinder disposed within the housing, wherein the wedge-shaped wire screen cylinder is the aforementioned filter element.

3. The continuous filtration process according to claim 1, characterized in that: In step four, the steps for regenerating PVPP in group one are as follows: 1) Bring brewing water at a temperature >80℃ into Group 1 for rinsing, and then output the wastewater from Group 1. (ii) Add alkali to brewing water at >80℃, and then repeat the process of entering and exiting group one to perform alkali circulation; (iii) After the alkali cycle is completed, brewing water at >80℃ is introduced into Group 1 for rinsing. The rinsing wastewater is discharged from Group 1 to drain the alkali solution in Group 1. (iv) Add acid to brewing water at >80℃, and then repeat the process of entering and exiting group one to perform acid circulation; (v) After the acid cycle is completed, brewing water at >80℃ is introduced into Group 1 for rinsing. The rinsing wastewater is discharged from Group 1 to drain the acid liquid in Group 1.

4. The continuous filtration process according to claim 3, characterized in that: In steps one), three), and five), the method for rinsing the brewing water is as follows: First, brewing water at temperatures above 80°C is introduced into Group 1 for rinsing. After rinsing, the wastewater is discharged. Then, the brewing water at temperatures above 80°C is repeatedly introduced into and out of Group 1 for hot water circulation.

5. The continuous filtration process according to claim 3, characterized in that: The acid and / or alkali cycle time is 30 min.

6. The continuous filtration process according to claim 1, characterized in that: The filter assembly has an inlet for inputting the beer to be filtered and the PVPP dispersion, and an outlet for outputting the filtered beer. In step four, the process of collecting the regenerated PVPP into the PVPP storage tank is as follows: Deoxygenated water is introduced into Group 1 through the outlet, so that the regenerated PVPP in Group 1 is backflushed into the PVPP storage tank through the inlet; then carbon dioxide gas is introduced into Group 1 through the outlet, so that the deoxygenated water in Group 1 is compressed into the PVPP storage tank through the inlet.

7. The continuous filtration process according to claim 6, characterized in that: The process of collecting the regenerated PVPP into the PVPP storage tank can be selectively repeated. Finally, the first group is filled with deoxygenated water, thus ensuring that the first group is filled with deoxygenated water.

8. The continuous filtration process according to claim 7, characterized in that: In step three, when the filtration capacity of group one is about to reach saturation, the beer to be filtered and the PVPP dispersion are first fed into group two to push out the deoxygenated water in group two and discharge the wastewater. The beer output from group two is fed into group one for filtration, and the filtered beer is output from group one.

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