PH value control system for producing liquid packaging paper

Abstract

The utility model discloses a PH value control system for producing liquid packaging paper. The PH value control system comprises a white water tank, a hydrapulper, a chain scraper conveyor, a pulping machine, a surface layer pulp mixing tank, a core layer pulp mixing tank, a bottom layer pulp mixing tank and a monitoring center, the pulp after being pulped by the hydrapulper is stored by a plurality of pulp pumps, filtered and screened, and then is pumped into the pulping machine; a flowmeter used for monitoring the addition amount of liquid caustic soda is arranged at the synchronous pumping liquid caustic soda position while the white water in the white water tank is added into the hydrapulper; a repulping concentration detector used for monitoring the PH value of repulped pulp is further mounted at a repulping outlet of the hydrapulper; a pulping concentration detector used for monitoring the PH value of pulping pulp is further mounted at a pulping outlet of the pulping machine; when paper is processed on the surface pulp line, the bottom pulp line and the pulp preparation line, the PH value of the pulp is adjusted by the monitoring center according to detection signals monitored by the repulping concentration detector and the grinding concentration detector and by controlling the addition amount of the pumped liquid caustic soda through the flow meter.

Description

[Technical field]

[0001] The utility model relates to the production technology of dairy packaging paper, in particular to a pH value control system used for producing liquid packaging paper. [Background technology]

[0002] As an integral part of dairy products or liquid beverages, packaging has emerged along with the development of the dairy products or liquid beverage industry, and has a profound impact on the development of the dairy products or liquid beverage industry. Different dairy products or liquid beverages are suitable for different packaging. Among them, there are mainly the following packaging categories according to dairy products: 1. Fresh milk packaging mainly includes Tetra Pak, Combibloc, Tetra Pak pillow, roof bag, Bailey bag and composite plastic film bag, etc. According to the different packaging material structures, it can be used for the packaging of pasteurized milk, ultra-high temperature sterilized (UHT) milk and flavored milk; yogurt and flavored milk are mainly packaged in cups, plastic bottles and a small amount of glass bottles. Among them, the packaging of the roof bag is basically made of all pulp, and the PE layer is only a coating, so the sealing is poor, which is suitable for pasteurized fresh products; its identification feature is that it has a roof, some are centrally symmetrical roofs, and some are sloping roofs.

[0003] In the existing production of packaging paper for rooftop bags or liquid beverage bags, sizing is performed in the pulp using sizing agent AKD, and the pH value in the three-layer headbox is required to be controlled between 7.5-8.5. However, during the production process, due to the degree of cleaning of the pulp itself, the amount of various chemicals used, and the recycling of damaged paper, the pH value of the system will change, affecting the sizing effect. In the existing technology, only the pH value of the headbox is monitored and then adjusted by adding alkali to the tank outside the machine. The monitoring is lagging, the pH value of the entire system fluctuates greatly, and the lactic acid edge seepage of the finished paper is prone to large fluctuations, which seriously affects the production quality of packaging paper for rooftop bags or liquid beverage bags. There is an urgent need to adjust and improve the existing monitoring equipment. [Contents of the utility model]

[0004] The utility model provides a pH value control system for producing liquid packaging paper, which optimizes the control of pH value in the production process, ensures the stability of lactic acid edge permeation in the finished paper, and improves the production quality and production efficiency of the packaging paper.

[0005] The technical solution adopted by the utility model to solve its technical problems is:

[0006] A pH control system for producing liquid packaging paper, comprising a white water tank, a hydraulic pulper, a chain conveyor, a pulping machine, a surface layer pulping tank, a core layer pulping tank, a bottom layer pulping tank and a monitoring center, wherein the chain conveyor conveys various pulp sheets into the hydraulic pulper through a chain, and white water from the white water tank is added to the hydraulic pulper and liquid alkali is pumped into the hydraulic pulper to adjust the pH value;

[0007] The pulp after pulping by the hydraulic pulper is stored, filtered and screened by a plurality of pulp pumps and then pumped into the pulping machine. The pulp after grinding by the pulping machine is respectively transported to the surface layer pulping tank, the core layer pulping tank and the bottom layer pulping tank for pulping respectively, and then pumped into the surface pulp line, bottom pulp line and stock preparation line of the paper machine for papermaking processing;

[0008] When adding white water from the white water tank to the hydraulic pulper, a flow meter for monitoring the amount of liquid alkali added is provided at the place where the liquid alkali is pumped in synchronously, and the flow signal measured and controlled by the flow meter is directly fed back to the monitoring center;

[0009] A pulping concentration detector for monitoring the pH value of the pulped slurry is also installed at the pulping outlet of the hydraulic pulper, and the pulping concentration detector is used to directly feed back the monitored pH value signal of the pulped slurry to the monitoring center;

[0010] A refining concentration detector for monitoring the pH value of the refining slurry is also installed at the refining outlet of the refiner, and the refining concentration detector is used to directly feed back the monitored pH value signal of the refining slurry to the monitoring center;

[0011] During papermaking on the surface stock line, bottom stock line and stock preparation line, the monitoring center adjusts the pH value of the pulp according to the pH value of the pulped pulp monitored by the pulping concentration detector and the pH value of the refined pulp monitored by the refining concentration detector, and then controls the amount of liquid alkali added pumped in through the flow meter to adjust the pH value of the pulp.

[0012] Preferably, a dough flow concentration detector for monitoring the pH value of the dough slurry is also installed at the dough outlet of the dough layer mixing tank, and the dough flow concentration detector is used to directly feed back the monitored dough slurry pH value signal to the monitoring center;

[0013] A core slurry flow concentration detector for monitoring the pH value of the core slurry is also installed at the core slurry outlet of the core layer slurry preparation tank. The core slurry flow concentration detector is used to directly feed back the monitored core slurry pH value signal to the monitoring center;

[0014] A bottom slurry flow concentration detector for monitoring the pH value of the bottom slurry is also installed at the bottom slurry outlet of the bottom slurry mixing tank. The bottom slurry flow concentration detector is used to directly feed back the monitored bottom slurry pH value signal to the monitoring center;

[0015] During papermaking processing on the surface stock line, bottom stock line and stock preparation line, the monitoring center adjusts the pH value of the slurry according to the pH value of the surface stock slurry monitored by the surface stock flow concentration detector, the pH value of the core stock slurry monitored by the core stock flow concentration detector and the pH value of the bottom stock slurry monitored by the bottom stock flow concentration detector, and then controls the amount of liquid alkali added pumped in through the flowmeter.

[0016] The beneficial effects of the utility model are:

[0017] When the chain conveyor conveys various pulp sheets into the hydraulic pulper through the chain, the pH value is first adjusted by controlling the amount of white water added to the white water tank and the amount of liquid alkali pumped into the hydraulic pulper to achieve preliminary concentration adjustment; secondly, when the surface pulp line, bottom pulp line and stock preparation line are processed into paper, the monitoring center adjusts the pH value of the pulp by controlling the amount of liquid alkali added by the flow meter according to the pH value of the pulping slurry monitored by the pulping concentration detector and the pH value of the grinding slurry monitored by the grinding concentration detector; finally, when the surface pulp line, bottom pulp line and stock preparation line are processed into paper, the surface pulp line monitored by the monitoring center is again The pH value of the surface pulp is monitored by the pulp flow and pulp concentration detector, the pH value of the core pulp is monitored by the core pulp flow and pulp concentration detector, and the pH value of the bottom pulp is monitored by the bottom pulp flow and pulp concentration detector. The pH value of the pulp is further adjusted by controlling the amount of liquid alkali added by the flow meter. The pulping and alkali addition time is optimized in time according to the test data, and the alkali supplement amount is adjusted to adjust the liquid alkali addition flow at the white water tank outside the machine to keep the pH value stable between 7.5 and 8.5, which effectively optimizes the control of pH value in the production process, ensures the stability of lactic acid edge seepage of the finished paper in the production process, and improves the production quality and efficiency of packaging paper.

Brief Description of the Drawings

[0018] Figure 1 It is a schematic diagram of the system principle of the utility model. [Specific implementation method]

[0019] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0020] A pH control system for producing liquid packaging paper, such as Figure 1 As shown, it includes a white water tank 1, a hydraulic pulper 2, a chain conveyor 3, a pulping machine 4, a surface layer pulping tank 5, a core layer pulping tank 6, a bottom layer pulping tank 7 and a monitoring center 8. The chain conveyor 3 conveys various pulp plates into the hydraulic pulper 2 through a chain, and adds white water from the white water tank 1 and pumps liquid alkali into the hydraulic pulper 2 to adjust the pH value; the pulp after pulping by the hydraulic pulper 2 is stored, filtered and screened through multiple pulp pumps, and then pumped into the pulping machine 4; the pulp after grinding by the pulping machine 4 is respectively conveyed to the surface layer pulping tank 5, the core layer pulping tank 6 and the bottom layer pulping tank 7 for pulping respectively, and then pumped into the surface pulp line, bottom pulp line and stock preparation line of the paper machine for papermaking processing.

[0021] Continue as Figure 1As shown, when white water is added to the white water tank 1 on the hydraulic pulper 2 and the liquid alkali is pumped in synchronously, a flow meter 9 for monitoring the amount of liquid alkali added is provided, and the flow signal measured and controlled by the flow meter 9 is directly fed back to the monitoring center 8; a pulping concentration detector 10 for monitoring the pH value of the pulped slurry is also installed at the pulping outlet of the hydraulic pulper 2, and the pulping concentration detector 10 is used to directly feed back the monitored pH value signal of the pulped slurry to the monitoring center 8; a refining concentration detector 11 for monitoring the pH value of the refining slurry is also installed at the pulping outlet of the pulper 4, and the refining concentration detector 11 is used to directly feed back the monitored pH value signal of the refining slurry to the monitoring center 8; when the surface pulp line, the bottom pulp line and the stock preparation line are processed into paper, the monitoring center 8 adjusts the pH value of the pulp by controlling the amount of liquid alkali added pumped in through the flow meter 9 according to the pH value of the pulped slurry monitored by the pulping concentration detector 10 and the pH value of the refining slurry monitored by the pulping concentration detector 11.

[0022] Continue as Figure 1 As shown, a dough flow concentration detector 12 for monitoring the pH value of the dough slurry is installed at the dough outlet of the surface layer slurry mixing tank 5. The dough flow concentration detector 12 is used to directly feed back the monitored dough slurry pH value signal to the monitoring center 8; a core slurry flow concentration detector 13 for monitoring the pH value of the core slurry is also installed at the core slurry outlet of the core layer slurry mixing tank 6. The core slurry flow concentration detector 13 is used to monitor the pH value of the core slurry. 3 is used to directly feed back the monitored core pulp PH value signal to the monitoring center 8; a bottom pulp flow concentration detector 14 for monitoring the bottom pulp PH value is also installed at the bottom pulp outlet of the bottom pulp preparation tank 7, and the bottom pulp flow concentration detector 14 is used to directly feed back the monitored bottom pulp PH value signal to the monitoring center 8; during the papermaking processing of the surface pulp line, the bottom pulp line and the stock preparation line, the monitoring center 8 adjusts the PH value of the pulp by controlling the amount of liquid alkali added pumped in through the flow meter 9 according to the surface pulp PH value of the surface pulp slurry monitored by the surface pulp flow concentration detector 12, the core pulp PH value monitored by the core pulp flow concentration detector 13 and the bottom pulp slurry monitored by the bottom pulp flow concentration detector 14, so as to timely optimize the pulping alkali adding time and keep the PH value stable between 7.5-8.5.

[0023] In this embodiment, when the chain conveyor 3 conveys various pulp plates into the hydraulic pulper 2 through the chain, the pH value is first adjusted by controlling the amount of white water added to the white water tank 1 and the amount of liquid alkali pumped into the hydraulic pulper 2 to achieve preliminary concentration adjustment. Secondly, in order to better monitor the pH value, the monitoring point is moved forward, and the pH value monitoring of the pulp at the outlet of the pulper, the refiner 4, and the white water tank 1 is added. When the surface pulp line, the bottom pulp line, and the stock preparation line are processed into paper, the monitoring center 8 controls the amount of liquid alkali added by the flow meter 9 according to the pH value of the pulped pulp monitored by the pulping concentration detector 10 and the pH value of the refined pulp monitored by the pulping concentration detector 11 to adjust the pH value of the pulp; and the surface pulp slurry pH value monitored by the surface pulp flow concentration detector 12 monitored by the monitoring center 8 is H value, the core pulp slurry pH value monitored by the core pulp flow concentration detector 13 and the bottom pulp slurry pH value monitored by the bottom pulp flow concentration detector 14, adjust the amount of alkali supplement, and further adjust the pH value of the slurry by controlling the amount of liquid alkali added pumped in through the flow meter 9, adjust the liquid alkali addition flow rate at the white water tank 1 outside the machine, optimize the pulping alkali addition time in time according to the detection data, keep the pH value stable at 7.5-8.5, effectively optimize the control of pH value in the production process, and ensure the stability of lactic acid edge seepage of finished paper during the production process.

[0024] The above-described embodiments are only preferred embodiments of the present invention and are not intended to limit the scope of implementation of the present invention. All equivalent changes made based on the shape, structure and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A pH control system for producing liquid packaging paper, characterized in that: It includes a white water tank, a hydraulic pulper, a chain conveyor, a pulping machine, a surface layer pulping tank, a core layer pulping tank, a bottom layer pulping tank and a monitoring center. The chain conveyor conveys various pulp plates into the hydraulic pulper through a chain, and adds white water from the white water tank and pumps in liquid alkali to the hydraulic pulper to adjust the pH value. The pulp after pulping by the hydraulic pulper is stored, filtered and screened by a plurality of pulp pumps and then pumped into the pulping machine. The pulp after grinding by the pulping machine is respectively transported to the surface layer pulping tank, the core layer pulping tank and the bottom layer pulping tank for pulping respectively, and then pumped into the surface pulp line, bottom pulp line and stock preparation line of the paper machine for papermaking processing; When adding white water from the white water tank to the hydraulic pulper, a flow meter for monitoring the amount of liquid alkali added is provided at the place where the liquid alkali is pumped in synchronously, and the flow signal measured and controlled by the flow meter is directly fed back to the monitoring center; A pulping concentration detector for monitoring the pH value of the pulped slurry is also installed at the pulping outlet of the hydraulic pulper, and the pulping concentration detector is used to directly feed back the monitored pH value signal of the pulped slurry to the monitoring center; A refining concentration detector for monitoring the pH value of the refining slurry is also installed at the refining outlet of the refiner, and the refining concentration detector is used to directly feed back the monitored pH value signal of the refining slurry to the monitoring center; During papermaking on the surface stock line, bottom stock line and stock preparation line, the monitoring center adjusts the pH value of the pulp according to the pH value of the pulped pulp monitored by the pulping concentration detector and the pH value of the refined pulp monitored by the refining concentration detector, and then controls the amount of liquid alkali added pumped in through the flow meter to adjust the pH value of the pulp.

2. A pH control system for producing liquid packaging paper according to claim 1, characterized in that: A dough flow concentration detector for monitoring the pH value of the dough slurry is also installed at the dough outlet of the dough mixing tank, and the dough flow concentration detector is used to directly feed back the monitored dough slurry pH value signal to the monitoring center; A core slurry flow concentration detector for monitoring the pH value of the core slurry is also installed at the core slurry outlet of the core layer slurry preparation tank. The core slurry flow concentration detector is used to directly feed back the monitored core slurry pH value signal to the monitoring center; A bottom slurry flow concentration detector for monitoring the pH value of the bottom slurry is also installed at the bottom slurry outlet of the bottom slurry mixing tank. The bottom slurry flow concentration detector is used to directly feed back the monitored bottom slurry pH value signal to the monitoring center; During papermaking processing on the surface stock line, bottom stock line and stock preparation line, the monitoring center adjusts the pH value of the slurry according to the pH value of the surface stock slurry monitored by the surface stock flow concentration detector, the pH value of the core stock slurry monitored by the core stock flow concentration detector and the pH value of the bottom stock slurry monitored by the bottom stock flow concentration detector, and then controls the amount of liquid alkali added pumped in through the flowmeter.

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