A method for rapid determination of the coarse pulp rate of a papermaking process reconstituted tobacco pulp

Abstract

The application discloses a kind of papermaking method reconstituted tobacco slurry crude pulp rate fast determination method, mainly including the following steps: (1) accurately take slurry sample;(2) slurry sample has been weighed, defibration, concentration;(3) screen mesh selection and installation;(4) first pulp chamber slurry collection bag and overflow port slurry collection bag pretreatment and installation;(4) screen pulp;(5) slurry collection after screening;(6) centrifugal dewatering;(7) weighing calculation.The application realizes the accurate detection of papermaking method reconstituted tobacco slurry crude pulp rate, uses centrifugal dewatering instead of traditional vacuum suction dewatering and drying treatment, greatly shortens the detection time, provides a determination method for the whole papermaking method reconstituted tobacco slurry production process, can be used to guide slurry production operation control, provides basis for papermaking method reconstituted tobacco slurry quality optimization, control, simultaneously, provides data support for papermaking method reconstituted tobacco product quality improvement, has important guiding significance to production practice.

Description

A rapid method for determining the rough pulp ratio of reconstituted tobacco pulp in papermaking Technical Field

[0001] This invention belongs to the field of reconstituted tobacco production technology, and specifically relates to a rapid method for determining the rough pulp ratio of reconstituted tobacco pulp produced by papermaking. Background Technology

[0002] Pulping technology utilizes beating equipment to mechanically transform insoluble materials through a series of longitudinal and transverse morphological changes, such as disintegration, cutting, and fiber separation, ultimately forming pulp suitable for papermaking. Due to the characteristics of tobacco raw materials, the pulping process for reconstituted tobacco in papermaking primarily involves material disintegration, cutting, and breaking down. The "coarseness" and "fineness" of the pulp are often controlled by adjusting the work done by the beating equipment. Generally, the coarser the pulp in reconstituted tobacco for papermaking, the higher the product thickness, bulk, and filling value, and the better its absorbency.

[0003] Currently, the domestic industry generally uses the beating degree and wet weight index and their testing equipment from the papermaking industry to evaluate the quality of reconstituted tobacco pulp. However, due to the significant differences between the composition and fiber morphology of tobacco raw materials and traditional wood pulp, the impurities in tobacco leaves are more easily broken down than fiber cells during beating. Therefore, the beating degree of tobacco leaves is often much higher than that of tobacco stems, causing the overall beating degree of the mixed pulp to quickly reach the target value. In reality, the pulp is not well processed, and the measured beating degree cannot reflect the true performance state of the pulp. During wet weight measurement, broken tobacco leaves are not easy to retain on the metal frame, and tobacco stem fibers, due to their short, hard, and irregular shape, are easily lost with water through the gaps in the metal frame compared to the soft and malleable wood pulp fibers. This results in low accuracy and weak representativeness of the test results. The traditional beating degree and wet weight index of the pulp are not strongly correlated with key physical indicators such as tensile strength and thickness of reconstituted tobacco leaves.

[0004] The existing standard "Method for Determination of Pulp Sieving" (GB / T 2678.1-93) specifies a method for determining the distribution of pulp fibers in the papermaking industry. This method involves passing pulp fibers sequentially through square-hole sieves of different mesh sizes. The square-hole sieve design is more suitable for the detection and performance evaluation of reconstituted tobacco pulp in papermaking processes where sheet-like, block-like, and fibrous components coexist. However, this method uses a five-level sieve grading system and is mainly used in research to determine the structural distribution of pulp fibers at each mesh size, or to perform pre-treatment grading of pulp fibers, followed by further analysis of the fibers within each mesh size range after grading. The current research analysis is not suitable for detecting the crude pulp ratio of reconstituted tobacco pulp produced by papermaking. In addition, each stage of pulp after screening needs to be vacuum-dehydrated and collected separately. The vacuum suction force cannot be too strong, otherwise the filter paper on the suction cup will be torn, resulting in a vacuum suction time of about 40 minutes. After collection, each stage of pulp after screening needs to be transferred to a weighing box and dried to constant weight. Finally, the weight is weighed and the results are calculated. The whole process is cumbersome and complicated, and the testing of a single sample takes at least 6 hours. Therefore, it is not suitable for the rapid determination and evaluation of the performance of reconstituted tobacco pulp produced by papermaking.

[0005] Therefore, in actual production, operators often need to judge the "coarseness" and "fineness" of the pulp based on experience, and adjust the parameters of the pulping equipment from time to time based on this. As a result, the quality and stability of the pulp are affected, the means of optimizing the pulping process and the physical properties of reconstituted tobacco are limited, and the industry's pace of development from large scale to refinement is hindered. Summary of the Invention

[0006] To address the shortcomings of existing technologies, this invention discloses a rapid method for determining the rough pulp ratio of reconstituted tobacco pulp, based on the characteristics of the pulp produced by papermaking. This method enables accurate and rapid determination of the performance of reconstituted tobacco pulp, providing a basis for judgment throughout the entire reconstituted tobacco pulp production process. It can be used to guide the control of pulping production operations. Furthermore, based on the correlation between the rough pulp ratio and the quality of the reconstituted tobacco substrate and finished product, the method optimizes pulp quality to improve the quality and stability of the substrate and finished product.

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] A rapid method for determining the rough pulp ratio of reconstituted tobacco pulp in papermaking is described below:

[0009] (1) Accurately weigh the reconstituted tobacco pulp for papermaking;

[0010] (2) Pour the weighed slurry into the fiber dissociator and disperse it for (3-5) minutes to ensure that there are no lumps in the slurry after dissociation. Transfer the slurry to a beaker and dilute it with water to the target concentration.

[0011] (3) Select a (10-20) mesh sieve plate and install it into the first pulp chamber of the Pall sieve analyzer. Do not install sieve plates in the other pulp chambers. Check whether the plugs at the pulp outlets of each pulp chamber are tightly sealed.

[0012] (4) Mark the two slurry collection bags as the first slurry chamber slurry collection bag and the overflow port slurry collection bag respectively. Immerse the two slurry collection bags in water for (1-2) min, then take them out and spin dry in a centrifuge for (6-10) min and weigh them. Record them as M0 and M1 respectively.

[0013] (5) Tie the weighed slurry collection bag from step (4) to the outlet and overflow of the first slurry chamber according to the markings.

[0014] (6) Pour the slurry suspension from step (2) into the slurry injection port of the Pall screener within 10 seconds, start the timer, and screen the slurry for (8-10) minutes.

[0015] (7) After the slurry screening is completed, remove the plugs from the slurry outlets of each slurry chamber, use the slurry collection bag of the first slurry chamber to collect the slurry in the first slurry chamber of the Pall screener, and use the slurry collection bag at the overflow port to collect the slurry in the remaining slurry chambers without screen plates in sequence. During collection, the residual slurry in each slurry chamber must be rinsed clean.

[0016] (8) Place the slurry collection bag in the first slurry chamber and the slurry collection bag at the overflow outlet into a centrifugal dewatering machine for centrifugation (5-8) min, then take them out and weigh them, and record them as M2 and M3 respectively.

[0017] (9) Calculate the coarse pulp ratio of the tested slurry sample. The calculation formula is as follows:

[0018]

[0019] In the formula:

[0020] M0 – Weight of the first pulp chamber pulp collection bag, in grams

[0021] M1 — Weight of the slurry collection bag at the overflow outlet, in grams

[0022] M2 — Weight of the slurry collected in the first slurry chamber after centrifugation following screening, in grams.

[0023] M3 — Weight of slurry collected in the overflow bag after centrifugation after screening, in grams.

[0024] Further, in step (1), accurately weigh 15-20 g of reconstituted tobacco pulp for papermaking with a dry weight of (0.01-0.0001) g.

[0025] Further, in step (2), the concentration is diluted to (0.5-1.5) wt%.

[0026] Furthermore, in step (2), the slurry collection bag has a mesh size of ≥200 mesh.

[0027] Furthermore, in steps (4) and (8), the weighing accuracy is (0.01~0.0001)g.

[0028] This invention enables accurate and rapid detection of the coarse pulp ratio in reconstituted tobacco pulp produced by papermaking, providing a basis for optimizing and controlling the quality of reconstituted tobacco pulp produced by papermaking, and providing data support for improving the quality of reconstituted tobacco products produced by papermaking. It has important guiding significance for production practice. Detailed Implementation

[0029] The following implementation examples are provided to illustrate the present invention in more detail. It should be noted that the following implementation examples should not be construed as limiting the scope of protection of the present invention. Non-essential improvements and adjustments made to the present invention by those skilled in the art based on the above description should still fall within the scope of protection of the present invention.

[0030] Example 1:

[0031] A rapid method for determining the rough pulp ratio of reconstituted tobacco pulp produced by papermaking is disclosed. Nine groups of pulps from three different processing stages in a reconstituted tobacco production line (after low-consistency disc mill, after cylindrical refiner, and after screening) are used to determine the rough pulp ratio. 15g (octane-dry weight) of each pulp is accurately weighed to the nearest 0.0001g. The weighed pulp is poured into a fiber disintegrator and dispersed for 3 minutes to ensure uniform dispersion and prevent pulp lumps. The dispersed pulp is then transferred to a 5L beaker and diluted to a concentration of 0.5wt%. A Pall sieve is used; the first chamber is equipped with a 12-mesh sieve, while the other chambers are not. The plugs at the pulp outlets of each chamber are checked for tight sealing. Two 400-mesh pulp collection bags are labeled as the first chamber collection bag and the overflow collection bag, respectively. These two collection bags are immersed in water for 2 minutes, then removed and centrifuged in a centrifuge. After drying for 8 minutes, weigh the slurry to an accuracy of 0.0001g and record them as M0 and M1 respectively. Then, tie the marked and weighed slurry collection bags to the outlet and overflow of the first slurry chamber respectively. Pour the concentrated slurry suspension into the slurry inlet of the Pall sieve within 10 seconds, start the timer, and sieve the slurry for 8 minutes. After sieving, remove the plugs of the slurry outlets of each slurry chamber. Use the slurry collection bag of the first slurry chamber to collect the slurry in the first slurry chamber of the Pall sieve. Use the slurry collection bag at the overflow outlet to collect the slurry of the remaining slurry chambers in sequence. Each slurry chamber must be rinsed clean to ensure that there is no slurry residue. Then, place the slurry collection bags of the first slurry chamber and the slurry collection bags at the overflow outlet into a centrifuge for centrifugation for 5 minutes, take them out and weigh them to an accuracy of 0.0001g, and record them as M2 and M3 respectively. Calculate the coarse slurry ratio of each slurry and test the traditional beating degree and wet weight for comparison. The results are shown in Table 1.

[0032] The formulas for calculating the coarse pulp ratio of each slurry are as follows:

[0033]

[0034] In the formula:

[0035] M0 – Weight of the first pulp chamber pulp collection bag, in grams

[0036] M1 — Weight of the slurry collection bag at the overflow outlet, in grams

[0037] M2 — Weight of the slurry collected in the first slurry chamber after centrifugation following screening, in grams.

[0038] M3 — Weight of the slurry collected in the overflow bag after centrifugation, in grams.

[0039] Table 1 Comparison of coarse pulp ratio and conventional wet weight and beating degree of reconstituted tobacco pulp by papermaking method.

[0040]

[0041] Table 1 shows that during the production of reconstituted tobacco using the papermaking method, the coarse pulp ratio exhibits a regular change from one processing step to the next, which is consistent with the experience results of on-site operators. It can reflect the "coarse" and "fine" degree of the pulp. The corresponding traditional freeness index does not change significantly, and the traditional wet weight index has too small a base, making it difficult to distinguish papermaking reconstituted tobacco pulp of different quality states. The coarse pulp ratio index can be used as an evaluation index for the pulping process of papermaking reconstituted tobacco.

[0042] Example 2:

[0043] A rapid method for determining the rough pulp ratio of reconstituted tobacco pulp produced by papermaking is disclosed. Six groups of pulps from the cylindrical refiner at different beating intensities in a reconstituted tobacco production line were selected to determine the rough pulp ratio. 18g (octane-dry weight) of each pulp was accurately weighed to a depth of 0.0001g. The weighed pulp was poured into a fiber disintegrator and dispersed for 5 minutes to ensure uniform dispersion and prevent lumps. The dispersed pulp was then transferred to a 5L beaker and diluted to a concentration of 1.0wt%. A 12-mesh sieve was installed in the first chamber of a Pall sieve, while the other chambers were not. The plugs at the pulp outlets of each chamber were checked for tight sealing. Two 300-mesh pulp collection bags were labeled as the first chamber collection bag and the overflow collection bag, respectively. These two collection bags were immersed in water for 2 minutes, then removed and centrifuged for 8 minutes before being weighed to a depth of 0.0g. 0.001g, denoted as M0 and M1 respectively; two 300-mesh marked and weighed slurry collection bags are tied to the outlet and overflow of the first slurry chamber respectively. The concentrated slurry suspension is poured into the slurry inlet of the Pall sieve within 10 seconds. The timer is started, and the slurry is sieved for 8 minutes. After sieving, the plugs of the slurry outlets of each slurry chamber are removed. The slurry in the first slurry chamber of the Pall sieve is collected using the slurry collection bag of the first slurry chamber. The slurry collection bag at the overflow outlet is used to collect the slurry in the remaining slurry chambers in sequence. Each slurry chamber must be rinsed clean to ensure that there is no slurry residue. Then, the slurry collection bags of the first slurry chamber and the slurry collection bags at the overflow outlet are placed in a centrifuge for centrifugation for 8 minutes, and then taken out and weighed to an accuracy of 0.0001g, denoted as M2 and M3 respectively; the coarse slurry ratio of each slurry is calculated, and the traditional beating degree and wet weight are tested for comparison. At the same time, the quantitative amount of each slurry in papermaking is 60g / m³ under the same conditions. 2 The reconstituted tobacco substrate was tested for tensile strength and thickness.

[0044] The formulas for calculating the coarse pulp ratio of each slurry are as follows:

[0045]

[0046] In the formula:

[0047] M0 – Weight of the first pulp chamber pulp collection bag, in grams

[0048] M1 — Weight of the slurry collection bag at the overflow outlet, in grams

[0049] M2 — Weight of the slurry collected in the first slurry chamber after centrifugation following screening, in grams.

[0050] M3 — Weight of the slurry collected in the overflow bag after centrifugation, in grams.

[0051] Table 2. Physical properties of reconstituted tobacco pulp and substrate from papermaking process.

[0052]

[0053] Table 2 shows that during the production of reconstituted tobacco using the papermaking method, under different beating intensities, the coarse pulp ratio gradually decreased with increasing mill power, with a maximum and minimum coarse pulp ratio range of 24.12%. The conventional beating degree generally increased with increasing mill power, with a maximum and minimum beating degree range of 4.0°SR. The conventional wet weight generally decreased with increasing mill power, with a maximum and minimum wet weight range of 1.57g. The coarse pulp ratio index showed significantly higher baseline and variability than the conventional beating degree and wet weight. Furthermore, the coarse pulp ratio index showed a significant correlation with the tensile strength and thickness of the reconstituted tobacco substrate. Therefore, the coarse pulp ratio index can be used as an evaluation index for the pulping process of reconstituted tobacco using the papermaking method.

[0054] Example 3:

[0055] A rapid method for determining the rough pulp ratio of reconstituted tobacco pulp in a papermaking process is disclosed. The rough pulp ratio is determined using pulp from the pre-line feed of a reconstituted tobacco production line. The same pulp sample is measured 20 times, with each measurement using an accurate weight of 18g (octane-dry weight) to a minimum of 0.0001g. The weighed pulp is poured into a fiber disintegrator and dispersed for 4 minutes to ensure uniform dispersion and prevent pulp lumps. The dispersed pulp is then transferred to a 5L beaker and diluted to a concentration of 0.5wt%. A 20-mesh sieve is installed in the first chamber of a Pall sieve analyzer, while the other chambers are not. The plugs at the pulp outlets of each chamber are checked for tight sealing. Two 400-mesh pulp collection bags are labeled as the first chamber collection bag and the overflow collection bag, respectively. These two collection bags are immersed in water for 2 minutes, then removed and centrifuged for 8 minutes. After weighing, accurate to 0.0001g, and record as M0 and M1 respectively; tie two 400-mesh marked and weighed slurry collection bags to the outlet and overflow port of the first slurry chamber respectively; pour the concentrated slurry suspension into the slurry inlet of the Pall sieve within 10s; start the timer and sieve for 10min; after sieving, remove the plugs from the outlets of each slurry chamber; the slurry collection bag of the first slurry chamber collects the slurry in the first slurry chamber of the Pall sieve; the slurry collection bag at the overflow port collects the slurry in the remaining slurry chambers in sequence; each slurry chamber must be rinsed clean to ensure no slurry residue; then place the slurry collection bag of the first slurry chamber and the slurry collection bag at the overflow port into a centrifuge for 6min and weigh them, accurate to 0.0001g, and record as M2 and M3 respectively; calculate the coarse slurry ratio to verify the repeatability of the slurry coarse slurry determination method.

[0056] The formulas for calculating the coarse pulp ratio of each slurry are as follows:

[0057]

[0058] In the formula:

[0059] M0 – Weight of the first pulp chamber pulp collection bag, in grams

[0060] M1 — Weight of the slurry collection bag at the overflow outlet, in grams

[0061] M2 — Weight of the slurry collected in the first slurry chamber after centrifugation following screening, in grams.

[0062] M3 — Weight of the slurry collected in the overflow bag after centrifugation, in grams.

[0063] Table 3 Repeatability of the method for determining the rough pulp ratio of reconstituted tobacco pulp in papermaking

[0064]

[0065]

[0066] Table 3 shows that the relative deviation of the rough pulp ratio of reconstituted tobacco pulp using the same papermaking method is within 3% in different test batches, indicating good repeatability and making it suitable for monitoring pulp indicators during the production process.

[0067] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the specific implementation of the present invention and not to limit it. Those skilled in the art should understand that any equivalent substitutions or obvious modifications made to the implementation of the present invention without changing its performance or use, without departing from the spirit of the present invention, should be covered within the scope of protection claimed by the present invention.

Claims

1. A rapid method for determining the rough pulp ratio of reconstituted tobacco pulp in papermaking, characterized in that, The process is as follows: (1) Accurately weigh the reconstituted tobacco pulp by papermaking method; (2) Pour the weighed pulp into the fiber disintegrator and disperse it for 3-5 minutes to ensure that there are no pulp clumps after disintegration. Transfer the dispersed pulp to a beaker and dilute it with water to the target concentration; (3) Select a 10-20 mesh sieve plate and install it in the first pulp chamber of the Pall sieve analyzer. Do not install sieve plates in the other pulp chambers. Check whether the plugs at the pulp outlets of each pulp chamber are sealed tightly; (4) Mark the two pulp collection bags as the pulp collection bag for the first pulp chamber and the pulp collection bag at the overflow outlet, respectively. Immerse these two pulp collection bags in water for 1-2 minutes, then take them out and spin dry in a centrifuge for 6-10 minutes before weighing them. Record them as M0 and M1, respectively; (5) Take the pulp weighed in step (4) (6) The collection bags are tied to the discharge port and overflow port of the first slurry chamber according to the markings; (7) The slurry suspension in step (2) is poured into the slurry injection port of the Pall sieve within 10 seconds, the timer is started, and the slurry is sieved for 8~10 minutes; (8) After the slurry sieve is completed, the plugs of the discharge ports of each slurry chamber are pulled out, the slurry in the first slurry chamber of the Pall sieve is collected by the slurry collection bag of the first slurry chamber, and the slurry in the other slurry chambers without sieve plates is collected by the slurry collection bag at the overflow port in turn. The residual slurry in each slurry chamber must be rinsed clean during collection; (9) The slurry collection bags of the first slurry chamber and the slurry collection bags at the overflow port are placed in the centrifuge dewatering machine for centrifugation for 5~8 minutes and then taken out and weighed, and recorded as M2 and M3 respectively; (10) The coarse slurry ratio of the slurry sample is calculated by the following formula: In the formula: M0——weight of the slurry collection bag in the first slurry chamber, g; M1——weight of the slurry collection bag at the overflow port, g; M2——weight of the slurry collection bag in the first slurry chamber after centrifugation after screening, g; M3——weight of the slurry collection bag at the overflow port after centrifugation after screening, g.

2. The rapid method for determining the rough pulp ratio of reconstituted tobacco pulp according to claim 1, characterized in that, In step (1), accurately weigh 15-20g of reconstituted tobacco pulp for papermaking with an absolute dry weight of 0.01-0.0001g.

3. The rapid method for determining the rough pulp ratio of reconstituted tobacco pulp according to claim 1, characterized in that, In step (2), the solution is diluted to a concentration of 0.5~1.5wt%.

4. The rapid method for determining the rough pulp ratio of reconstituted tobacco pulp according to claim 1, characterized in that, In step (2), the slurry collection bag has a mesh size of ≥200 mesh.

5. The rapid method for determining the rough pulp ratio of reconstituted tobacco pulp according to claim 1, characterized in that, In steps (4) and (8), the weighing accuracy is 0.01~0.0001g.

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