Half-split and half-closed type mixed counter-current extraction process and system for paper-making method tobacco sheets

Abstract

The invention relates to the technical field of tobacco sheets, and mainly relates to a semi-split semi-closed type mixed counter-current extraction process and system for paper-making method tobacco sheets. According to the method, the tobacco stems are independently treated, so that the process target of separate extraction is achieved, most of undesirable components in the tobacco stems are removed, and the fiber content of the tobacco stems is reserved while the treated tobacco stems are subjected to defibering; the wood pulp is directly put into the mixing pulper for treatment, so that a special wood pulp treatment process path and equipment are omitted, and the problems of formula deviation and the like caused by introduction of additional liquid in wood pulp pretreatment are avoided; the continuous mixing extraction target of'batch mixing of materials and continuous subsequent extraction 'is realized by using the extraction buffer tank; a mixing pump with high concentration tolerance is used for reducing process mixing and reducing the liquid adding amount, and it is ensured that the concentration of first-stage extraction liquid is controlled. The method is simple in process, low in equipment investment, small in occupied area and high in target achieving efficiency, and has good application value and economic value for current tobacco sheet production.

Description

Technical Field

[0001] The invention relates to the technical field of tobacco flakes, in particular to a semi-separated and semi-combined mixed countercurrent extraction process and system for tobacco flakes produced by a papermaking method. Background Art

[0002] Papermaking tobacco flakes are tobacco products (referred to as tobacco flakes, the same below) made from tobacco waste stems, flakes, etc. in cigarette production as raw materials, processed and reorganized using papermaking technology. They have the characteristics of low density, high filling value, excellent processability, and strong plasticity of product intrinsic quality and style characteristics. Driven by the goal of improving the quality of Chinese cigarette products, the production technology and quality of tobacco flakes have developed rapidly. In recent years, they have developed into an important raw material for Chinese cigarettes.

[0003] At present, the tobacco flake production industry adopts the overall process of "separation before combination", that is, the tobacco raw materials are first soaked in hot water (also known as extraction) and then squeezed to achieve solid-liquid separation. The liquid phase (i.e., the extract) is then purified, concentrated, and flavored to form a coating liquid. The solid phase (i.e., the pulp) is pulped, fiberized (mainly wood pulp) and filled (mainly light calcium carbonate), and paper-made to form a substrate; the coating liquid is then applied to the substrate through a coating process to achieve reorganization, and then dried and cut to form tobacco flakes that can be used for cigarette processing. With the deepening of the understanding and research of the extraction process in the tobacco flake industry, the extraction process has gradually developed towards mixed extraction: 1) The tobacco stems are pre-soaked, also known as pre-extraction, to remove some undesirable components in the tobacco stems; 2) After pre-extraction, the tobacco stems are mixed and stirred with the flakes, and then multi-stage extraction is performed to separate the solid and liquid components of the tobacco, which is referred to as the "half-separation and half-combination" mixed extraction process.

[0004] However, in the tobacco flake production industry, the application of mixed extraction mode varies from company to company, such as: 1) The mixed extraction process of a certain manufacturer is mainly based on the mixing of tobacco stems and flakes, and additional processing process paths and corresponding equipment are set for wood pulp to achieve process goals such as feeding, debonding, pulping, and blending of wood pulp. There are problems such as complex process paths, large equipment investment, many control nodes, and low controllability of blending ratio (blending accuracy is affected by multiple metering units); 2) In the mixed extraction process of a certain manufacturer, the wood pulp is pre-crushed to about 1.0*1.0cm and mixed into the flake storage cabinet, and then enters the mixed pulper together with the flakes, which still needs to be configured The separate wood pulp pretreatment process path and the corresponding crushing, metering and other equipment have problems such as it is difficult to evenly disperse the wood pulp fragments after entering the pulper, and there are metering errors between batches (tanks); 3) In the mixed extraction process of a certain third manufacturer, the squeezed and separated materials enter the extraction screw with the extraction water, and then are pumped into the lower squeezing equipment after mixing. There are a series of problems such as a lot of material accumulation in the extraction screw, difficult to clean, unsatisfactory mixing effect, and leakage; 4) In the mixed extraction process of a certain fourth manufacturer, the tobacco stems are dry-crushed to about 0.5cm and then pre-extracted with wood pulp, which seriously damages the length of the fiber material in the tobacco stems and affects the function of the fiber. As for other manufacturers that do not use the mixed extraction process, they adopt the mode of separate extraction and separate pulping. Their process path is more complicated, the equipment investment is larger, and the land area is larger, which is not conducive to the development of existing process technology.

[0005] Therefore, it is of great significance to improve the existing mixed extraction process and design a semi-separated and semi-combined mixed countercurrent extraction process with a simpler process path, more economical equipment investment and less floor space. Summary of the invention

[0006] In view of the problems existing in the prior art, the purpose of the present invention is to provide a half-separated and half-combined mixed countercurrent extraction process and system for papermaking tobacco slices. By implementing a mixed countercurrent extraction mode in which tobacco stems and slice ends are first extracted separately and then mixed and extracted, no additional wood pulp processing process path and equipment are added, and there is no situation of damaging the fibers in the tobacco stems. Higher extraction and separation efficiency can be achieved on the basis of a simpler process flow and less equipment investment, and it has good application value.

[0007] To achieve this object, the present invention adopts the following technical solutions:

[0008] The first aspect of the present invention provides a paper-making tobacco sheet semi-separation and semi-combination mixed countercurrent extraction process, comprising the following steps:

[0009] 1) Tobacco stem pre-extraction: adding extraction hot water, heated stem liquid, and tobacco stems to a tobacco stem pulper, mixing and stirring to obtain a mixed material 1; vibrating and screening the mixed material 1 to obtain extracted tobacco stems and free liquid; defibration processing the extracted tobacco stems, and performing solid-liquid separation on the defibration material to obtain pre-extracted tobacco stems and a liquid phase;

[0010] 2) Mixed extraction and pulping: adding the secondary extraction liquid, the primary extraction liquid, wood pulp, flakes and pre-extracted tobacco stems into a mixed pulper, mixing and stirring to obtain an extraction material 1;

[0011] 3) Continuous extraction: the extracted material is subjected to primary squeezing to obtain primary squeezed material and primary extraction liquid, the primary squeezed material is sent to a secondary mixing pump to be mixed with a tertiary extraction liquid, the secondary extraction is subjected to secondary squeezing to obtain a secondary squeezed material and a secondary extraction liquid, the secondary extraction liquid is returned to the secondary squeezed material and sent to a tertiary mixing pump to be mixed with hot extraction water, the tertiary extraction is subjected to tertiary squeezing to obtain a tertiary squeezed material and a tertiary extraction liquid, the tertiary squeezed material is mixed with diluted white water and then transported to the pulping section; wherein, the primary extraction liquid and the secondary extraction liquid are returned to the mixing pulper, and the tertiary extraction liquid is returned to the secondary mixing pump.

[0012] The second aspect of the present invention provides a semi-separated and semi-combined mixed countercurrent extraction system for paper-making tobacco sheets, comprising a pre-extraction unit, a mixed extraction unit, and a continuous extraction unit;

[0013] The pre-extraction unit includes a tobacco stem pulper, a tobacco stem vibrating screening machine, a defibrator and a tobacco stem squeezer; the tobacco stem pulper is provided with an extraction hot water inlet, a heating stem liquid inlet, a tobacco stem addition inlet, and a mixed material outlet; the tobacco stem vibrating screening machine is provided with a mixed material inlet, a free liquid outlet, and a post-extraction tobacco stem outlet, and the mixed material inlet is connected to the mixed material outlet of the tobacco stem pulper; the defibrator is provided with a post-extraction tobacco stem inlet and a post-fiberization material outlet, and the post-extraction tobacco stem inlet is connected to the post-extraction tobacco stem outlet of the tobacco stem vibrating screening machine; the tobacco stem squeezer is provided with a post-fiberization material inlet, a post-pre-extraction tobacco stem outlet and a liquid phase outlet, and the post-fiberization material inlet is connected to the post-fiberization material outlet of the defibrator;

[0014] The mixed extraction unit comprises a mixed pulper and an extraction buffer tank; the mixed pulper is provided with a secondary extraction liquid inlet, a primary extraction liquid inlet, a wood pulp inlet, a pre-extracted tobacco stem inlet, a sheet end inlet and an extraction material outlet; the pre-extracted tobacco stem inlet is connected to the pre-extracted tobacco stem outlet of the tobacco stem squeezer of the pre-extraction unit; the inlet of the extraction buffer tank is connected to the extraction material outlet of the mixed pulper;

[0015] The continuous extraction unit comprises a primary squeezer, a primary extraction liquid tank, a secondary mixing pump, a secondary squeezer, a secondary extraction liquid tank, a tertiary mixing pump, a tertiary squeezer and a tertiary extraction liquid tank; the primary squeezer, the secondary mixing pump, the secondary squeezer, the tertiary mixing pump and the tertiary squeezer are connected in sequence; the primary squeezer is provided with an extraction material inlet and a primary extraction liquid outlet, the extraction material inlet is connected with the outlet of the extraction buffer tank of the mixed extraction unit, the secondary mixing pump is provided with a tertiary extraction liquid inlet, the secondary extruder is provided with a secondary extraction liquid outlet, The three-stage mixing pump is provided with an extraction hot water inlet, the three-stage squeezing machine is provided with a three-stage squeezed material outlet and a three-stage extraction liquid outlet, the three-stage squeezed material outlet is connected with the pulping section; the inlet of the first-stage extraction liquid tank is connected with the first-stage extraction liquid outlet of the first-stage squeezing machine, and the outlet is connected with the first-stage extraction liquid inlet of the mixed pulping machine of the mixed extraction unit; the second-stage extraction tank is connected with the second-stage extraction liquid outlet of the second-stage squeezing machine and the second-stage extraction liquid inlet of the mixed pulping machine of the mixed extraction unit; the three-stage extraction tank is connected with the three-stage extraction liquid inlet of the second-stage mixing pump.

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[0017] 1. The semi-separated and semi-combined mixed countercurrent extraction process for papermaking tobacco slices provided by the present invention achieves the process goal of separate extraction first by treating the tobacco stems separately, so as to remove most of the undesirable components in the tobacco stems, and retains the fiber content while defibring the treated tobacco stems; the wood pulp is directly put into the mixing pulper for internal treatment, eliminating the need for a special wood pulp treatment process path and corresponding equipment, and avoiding the problem of formula deviation caused by the introduction of additional liquid during wood pulp pretreatment; the continuous mixed extraction goal of "batch mixing of materials and continuous subsequent extraction" is achieved by using an extraction buffer tank; and the mixing pump with high concentration tolerance is used to reduce process mixing, reduce the amount of liquid added, and ensure that the concentration of the primary extraction liquid is controlled.

[0018] 2. The semi-separated and semi-combined mixed countercurrent extraction system for paper-making tobacco sheets provided by the present invention achieves the goal of continuous mixed extraction by batch mixing of various materials and subsequent continuous extraction through the volume of the extraction buffer tank and the mixing volume of the mixing pulper.

[0019] 3. Compared with other extraction processes, the semi-separated and semi-combined mixed countercurrent extraction process for papermaking tobacco flakes provided by the present invention is simple, requires small equipment investment, occupies a small area, achieves high target efficiency, and has good application value and economic value for the current production of tobacco flakes. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 The present invention is a schematic flow chart of a semi-separated and semi-combined mixed countercurrent extraction system for papermaking tobacco sheets according to an embodiment of the present invention.

[0021] Figure markings: 1-tobacco stem pulper; 2-tobacco stem vibration screening machine; 3-fibrillator; 4-tobacco stem squeezer; 5-mixing pulper; 6-extraction buffer tank; 7-first-stage squeezer; 8-first-stage extraction liquid tank; 9-second-stage mixing pump; 10-second-stage squeezer; 11-second-stage extraction liquid tank; 12-third-stage mixing pump; 13-third-stage squeezer; 14-third-stage extraction liquid tank; 15-first-stage feed pump; 16-extraction hot water tank; 17-stem liquid collection tank; 18-tobacco stem pump; 19-pre-extraction tobacco stem buffer silo; 20-stem liquid heating tank; 21-unloading pump; 22-pre-knocking mixing pump; 23-dilution white water pump; 24-pre-knocking pulp tank; 25-end buffer silo. DETAILED DESCRIPTION

[0022] The following is a detailed description of the semi-separated and semi-combined mixed countercurrent extraction system and process for paper-making tobacco sheets of the present invention.

[0023] In order to overcome the problems existing in the existing process, the inventors achieved the process goal of separate extraction first by treating the tobacco stems separately, so as to remove most of the undesirable components in the tobacco stems and retain the fiber content and integrity of the tobacco stems; by directly putting the wood pulp into the mixing pulper, there is no need to set up a separate wood pulp processing process path and corresponding equipment, and the wood pulp pretreatment does not introduce additional liquid to cause problems such as formula deviation; the extraction buffer tank is used to achieve the goal of continuous mixed extraction of batch mixing of various materials and continuous subsequent extraction. The process is simple, the equipment investment is small, the footprint is small, and the target efficiency is high.

[0024] The present invention provides a semi-separated and semi-combined mixed countercurrent extraction process and system for paper-making tobacco sheets, and the specific technical scheme is as follows:

[0025] A semi-separated and semi-combined mixed countercurrent extraction process for papermaking tobacco sheets comprises the following steps:

[0026] 1) Tobacco stem pre-extraction: adding extraction hot water, heated stem liquid, and tobacco stems to a tobacco stem pulper, mixing and stirring to obtain a mixed material 1; vibrating and screening the mixed material 1 to obtain extracted tobacco stems and free liquid; defibration processing the extracted tobacco stems, and performing solid-liquid separation on the defibration material to obtain pre-extracted tobacco stems and a liquid phase;

[0027] 2) Mixed extraction and pulping: adding the secondary extraction liquid, the primary extraction liquid, wood pulp, flakes and pre-extracted tobacco stems into a mixed pulper, mixing and stirring to obtain an extraction material 1;

[0028] 3) Continuous extraction: the extracted material is subjected to primary squeezing to obtain primary squeezed material and primary extraction liquid, the primary squeezed material is sent to a secondary mixing pump to be mixed with a tertiary extraction liquid, the secondary extraction is subjected to secondary squeezing to obtain a secondary squeezed material and a secondary extraction liquid, the secondary extraction liquid is returned to the secondary squeezed material and sent to a tertiary mixing pump to be mixed with hot extraction water, the tertiary extraction is subjected to tertiary squeezing to obtain a tertiary squeezed material and a tertiary extraction liquid, the tertiary squeezed material is mixed with diluted white water and then transported to the pulping section; wherein, the primary extraction liquid and the secondary extraction liquid are returned to the mixing pulper, and the tertiary extraction liquid is returned to the secondary mixing pump.

[0029] In some embodiments of the present invention, in step 1), when the tobacco stem pulper is started, extraction hot water and heated stem liquid are added simultaneously, and then tobacco stems are added.

[0030] In some embodiments of the present invention, in step 1), the total volume of the extraction hot water and the heated stem liquid added for every 100 kg of tobacco stems is 0.55-0.65 m 3 The volume of hot water for extraction accounts for 55% to 65%, and the volume of heated stem liquid accounts for 35% to 45%.

[0031] In some embodiments of the present invention, in step 1), the mixing and stirring time is 15 to 25 minutes.

[0032] In some embodiments of the present invention, in step 1), the dryness of the tobacco stems after extraction is 12% to 17%.

[0033] In some embodiments of the present invention, in step 1), the dryness of the pre-extracted tobacco stems is 33% to 37%.

[0034] In some embodiments of the present invention, in step 2), the specific operation of adding the secondary extraction liquid, the primary extraction liquid, the wood pulp, the flakes and the pre-extracted tobacco stems to the mixer pulper includes: when the mixer pulper is started, the secondary extraction liquid and the primary extraction liquid are added simultaneously, and when the amount of the secondary extraction liquid and the primary extraction liquid added reaches 20 to 25 times the weight of the wood pulp, the wood pulp is added and stirred for 3 to 8 minutes, and when the addition of the secondary extraction liquid and the primary extraction liquid is completed, the flakes and the pre-extracted tobacco stems are added simultaneously. Preferably, the secondary extraction liquid and the primary extraction liquid are added at a constant flow rate for easy control.

[0035] In some embodiments of the present invention, in step 2), the mass ratio of the added flakes to the tobacco stems added in step 1) is 40-60:40-60, calculated as absolute dry material; the weight of the wood pulp added for every 100 kg of tobacco stems and flakes is 9-11 kg, calculated as absolute dry material.

[0036] In some embodiments of the present invention, in step 2), the total volume of the secondary extract and the primary extract added for every 100 kg of tobacco stems and flakes is 0.55-0.65 m 3 , wherein the volume proportion of the secondary extraction liquid is 55% to 65%, and the volume proportion of the primary extraction liquid is 35% to 45%.

[0037] In some embodiments of the present invention, in step 2), the mixing and stirring time is 15 to 25 minutes.

[0038] In some embodiments of the present invention, in step 3), the processing efficiency of the first-stage squeezing, the second-stage squeezing, and the third-stage squeezing are kept consistent, and the squeezing dryness is 33% to 37%. The squeezed material of each stage falls directly into the mixing pump of the next stage and mixes with the extraction liquid of the next stage.

[0039] In some embodiments of the present invention, in step 3), the third-stage extract added at the secondary mixing pump is 0.30-0.40 m3 / s per 100 kg of tobacco stems and flakes, based on absolute dry material. 3 , the extraction hot water added at the three-stage mixing pump is 0.30~0.40m 3 .

[0040] The second aspect of the present invention provides a paper-making tobacco sheet semi-separated and semi-combined mixed countercurrent extraction system, such as Figure 1 As shown, it includes a pre-extraction unit, a mixed extraction unit, and a continuous extraction unit;

[0041] The pre-extraction unit includes a tobacco stem pulper 1, a tobacco stem vibrating screening machine 2, a defibrating machine 3 and a tobacco stem squeezing machine 4; the tobacco stem pulper 1 is provided with an extraction hot water inlet, a heating stem liquid inlet, a tobacco stem addition inlet and a mixed material outlet; the tobacco stem vibrating screening machine 2 is provided with a mixed material inlet, a free liquid outlet and a post-extraction tobacco stem outlet, and the mixed material inlet is connected to the mixed material outlet of the tobacco stem pulper 1; the defibrating machine 3 is provided with a post-extraction tobacco stem inlet and a post-fibrating material outlet, and the post-extraction tobacco stem inlet is connected to the post-extraction tobacco stem outlet of the tobacco stem vibrating screening machine 2; the tobacco stem squeezing machine 4 is provided with a post-fibrating material inlet, a post-pre-extraction tobacco stem outlet and a liquid phase outlet, and the post-fibrating material inlet is connected to the post-fibrating material outlet of the defibrating machine 3;

[0042] The mixed extraction unit comprises a mixed pulper 5 and an extraction buffer tank 6; the mixed pulper 5 is provided with a secondary extraction liquid inlet, a primary extraction liquid inlet, a wood pulp inlet, a pre-extracted tobacco stem inlet, a sheet end inlet and an extraction material outlet; the pre-extracted tobacco stem inlet is connected to the pre-extracted tobacco stem outlet of the tobacco stem squeezer 4 of the pre-extraction unit; the inlet of the extraction buffer tank 6 is connected to the extraction material outlet of the mixed pulper 5;

[0043] The continuous extraction unit comprises a primary squeezer 7, a primary extraction liquid tank 8, a secondary mixing pump 9, a secondary squeezer 10, a secondary extraction liquid tank 11, a tertiary mixing pump 12, a tertiary squeezer 13 and a tertiary extraction liquid tank 14; the primary squeezer 7, the secondary mixing pump 9, the secondary squeezer 10, the tertiary mixing pump 12 and the tertiary squeezer 13 are connected in sequence; the primary squeezer 7 is provided with an extraction material inlet and a primary extraction liquid outlet, the extraction material inlet is connected with the outlet of the extraction buffer tank 6 of the mixed extraction unit, the secondary mixing pump 9 is provided with a tertiary extraction liquid inlet, the secondary squeezer 10 is provided with a secondary The extraction liquid outlet, the three-stage mixing pump 12 is provided with an extraction hot water inlet, the three-stage squeezing machine 13 is provided with a three-stage squeezed material outlet and a three-stage extraction liquid outlet, and the three-stage squeezed material outlet is connected to the pulping section; the inlet of the primary extraction liquid tank 8 is connected to the primary extraction liquid outlet of the primary squeezing machine 7, and the outlet is connected to the primary extraction liquid inlet of the mixed pulping machine 5 of the mixed extraction unit; the secondary extraction tank 11 is connected to the secondary extraction liquid outlet of the secondary squeezing machine 10 and the secondary extraction liquid inlet of the mixed pulping machine 5 of the mixed extraction unit; the three-stage extraction tank 14 is connected to the three-stage extraction liquid inlet of the secondary mixing pump 9.

[0044] In some embodiments of the present invention, a primary feed pump 15 is provided on the connecting pipeline between the extraction buffer tank 6 and the primary squeezer 7 for conveying the extraction material in the extraction buffer tank 6 to the primary squeezer 7 .

[0045] In some embodiments of the present invention, the volume of the extraction buffer tank 6 is 1.3 to 1.5 times the mixing volume of the mixer pulper 5, and the mixing volume of the mixer pulper 5 is 1.4 to 1.6 times the output volume of the primary feed pump 15, so as to ensure continuous discharge of the extraction buffer tank 6.

[0046] In some embodiments of the present invention, a pre-extracted tobacco stem buffer silo 19 is provided on the connecting pipeline between the tobacco stem squeezer 4 and the mixer pulper 5, the feed port of the pre-extracted tobacco stem buffer silo 19 is connected to the pre-extracted tobacco stem outlet of the tobacco stem squeezer 4, and the discharge port of the pre-extracted tobacco stem buffer silo 19 is connected to the pre-extracted tobacco stem inlet of the mixer pulper 5.

[0047] In some embodiments of the present invention, an extraction hot water tank 16 is further included, and the extraction hot water tank 16 is provided with an outlet 1 and an outlet 2, wherein the outlet 1 is connected to the extraction hot water inlet of the tobacco stem pulper 1 of the pre-extraction unit, and the outlet 2 is connected to the extraction hot water inlet of the three-stage mixing pump 12 of the continuous extraction unit.

[0048] In some embodiments of the present invention, the pre-extraction unit also includes a stem liquid collecting tank 17 and a stem liquid heating tank 20; the stem liquid collecting tank 17 is provided with a free liquid inlet, a squeezer liquid phase inlet and a stem liquid outlet, the free liquid inlet is connected to the free liquid outlet of the tobacco stem vibration screening machine 2, and the squeezer liquid phase inlet is connected to the liquid phase outlet of the tobacco stem squeezer 4; the stem liquid heating tank 20 is provided with a stem liquid inlet and a heated stem liquid outlet, the stem liquid inlet is connected to the stem liquid outlet of the stem liquid collecting tank, and the heated stem liquid outlet is connected to the heated stem liquid inlet of the tobacco stem pulper 1.

[0049] In some embodiments of the present invention, the secondary mixing pump 9 and the tertiary mixing pump 12 both adopt high-concentration solid-liquid mixing screw pumps. The high-concentration solid-liquid mixing screw pumps have high concentration tolerance and can transport media with a solid phase concentration of 14% to 18%. The present invention uses a high-concentration solid-liquid mixing screw pump in a continuous extraction unit to reduce process mixing and conveying equipment, reduce the amount of liquid added, and thus ensure that the concentration of the primary extraction liquid is controllable.

[0050] In some embodiments of the present invention, the pre-slurry mixing pump 22 is a medium-consistency solid-liquid mixing screw pump, which can transport a medium with a solid phase concentration of 5% to 7%, which is convenient for pulping.

[0051] The specific implementation mode of the present invention is further described in detail below in conjunction with preferred embodiments. When the embodiments provide numerical ranges, it should be understood that, unless otherwise specified in the present invention, the two endpoints of each numerical range and any numerical value between the two endpoints can be selected. Unless otherwise defined, all technical and scientific terms used in the present invention have the same meaning as those generally understood by those skilled in the art. The process equipment or devices not specifically noted in the following embodiments all adopt conventional equipment or devices in the field of papermaking tobacco sheets, such as various extraction tanks, delivery pumps, squeeze separation, liquid metering and control, etc. In addition to the specific methods, equipment, and materials used in the embodiments, as those skilled in the art grasp the prior art and the record of the present invention, any methods, equipment, and materials of the prior art similar or equivalent to the methods, equipment, and materials in the embodiments of the present invention can also be used to realize the present invention.

[0052] Example 1

[0053] A semi-separated and semi-combined mixed countercurrent extraction process for papermaking tobacco flakes, using Figure 1 The system comprises the following steps:

[0054] 1) Tobacco stem pre-extraction: Start the tobacco stem pulper 1 and add 5.00 ml of extraction hot water into the container of the tobacco stem pulper 1. 3 (from extraction hot water tank 16), heating stem liquid 4.00m 3(from the stem liquid heating tank), then add 1500kg of tobacco stems, stir and mix for 20 minutes to obtain a mixed material one; send the mixed material one to the tobacco stem vibration screening machine 2 through the tobacco stem pump 18, remove the free liquid by vibration screening to a dryness of 15%, and obtain extracted tobacco stems; send the extracted tobacco stems to the defibrator 3 for dissociation, and the dissociated material is separated from the solid by the tobacco stem squeezer 4 to obtain pre-extracted tobacco stems and a liquid phase with a dryness of 35%, and the pre-extracted tobacco stems are sent to the pre-extracted tobacco stem buffer silo 19 for standby; the free liquid removed by the tobacco stem vibration screening machine 2 and the liquid phase obtained by the solid-liquid separation of the tobacco stem squeezer 4 are sent to the stem liquid collecting tank 17, and part of the stem liquid in the stem liquid collecting tank 17 is refined and concentrated and then sent to the stem liquid heating tank 20, and refluxed to the container of the tobacco stem pulper 1 as heated stem liquid to achieve reuse.

[0055] 2) Mixed extraction and pulping: Start the mixer pulper 5, and add the secondary extraction liquid (from the secondary extraction liquid tank 11) and the primary extraction liquid (from the primary extraction liquid tank 8) into the container of the mixer pulper 5 at the same time, and wait until the added amount reaches 7.00 m 3 When the amount of secondary extract added reaches 11.00m 3 / tank, primary extract 7.00m 3 / tank, add 1500kg / tank of flakes (from flakes buffer silo 25) and pre-extracted tobacco stems (from pre-extracted tobacco stems buffer silo 19), and after stirring for 20 minutes, discharge the materials into extraction buffer tank 6 at one time through unloading pump 21 to obtain extraction material 1.

[0056] 3) Continuous extraction: The extraction material is pumped through a primary feed pump at a speed of about 15m 3 / h flow rate is continuously pumped into the primary squeezer 7 to obtain the primary squeezed material and the primary extract, the primary extract is sent to the primary extract tank 8, and refluxed to the mixing pulper 5 in step 2) to achieve reuse; the primary squeezed material and the tertiary extract are mixed at the secondary mixing pump 9, and the amount of the tertiary extract is 11.00m relative to 3000kg tobacco raw material. 3 The extracted material is pumped into the secondary squeezer through the secondary mixing pump 9 to obtain the secondary squeezed material and the secondary extract. The secondary extract is sent to the secondary extract tank 11 and refluxed to the mixing pulper 5 in step 2 to achieve reuse. The secondary squeezed material is mixed with the hot extraction water at the tertiary mixing pump 12. The amount of hot extraction water is 11.00m3 relative to 3000kg tobacco raw material. 3The extracted material obtained by extraction is pumped into the three-stage squeezer 13 through the three-stage mixing pump 12 to obtain the three-stage squeezed material and the three-stage extraction liquid. The three-stage squeezed material is sent to the pre-knocking mixing pump 22 and mixed with the diluted white water delivered by the dilution white water pump 23, and then sent to the pre-knocking pulp tank 24. The three-stage extraction liquid is sent to the three-stage extraction liquid tank 14 and refluxed to the two-stage mixing pump 9 for reuse; the operating frequency of the first, second and third stage squeezers is consistent, all of which are 16Hz, and the squeezed dryness is 35.0±1.5%. The squeezed material obtained by each stage of squeeze separation directly falls into the inlet of the mixing pump of the next stage and is mixed with the corresponding liquid.

[0057] Under the process path of this embodiment, a half-separated and half-combined continuous mixed extraction is adopted to achieve the process goals of mixing, extracting, and separating tobacco stems, flakes, wood pulp, and extraction water. The final dryness of the three-stage squeezer output is 35.5%, the concentration of the first-stage extract is 8.7%, the relative extraction rate of the tobacco stem pre-extraction can reach 68%, and the relative extraction rate of the three-stage extraction can reach 89%.

[0058] The mixed extraction process of a certain manufacturer is mainly based on the mixing of tobacco stems and flakes. Additional processing process paths and corresponding equipment are set up for wood pulp to achieve process goals such as wood pulp feeding, decomposition, pulping, and blending. There is no wood pulp involved in the mixed extraction, and it cannot play a "grid synergy" role in squeezing out the tobacco raw materials (wood pulp fibers can form a cross network in the mixed material, which can hold tiny tobacco fragments and further increase their squeezed dryness. As the squeezed dryness increases, the relative extraction rate increases). The squeezed dryness of the last stage of the mixed extraction is 30.0%±1.5%, the concentration of the first-stage extract is 7.0%-7.5%, the relative extraction rate of the tobacco stem pre-extraction is 45%-50%, and the relative extraction rate of the tertiary extraction is 80%-83%.

[0059] In the mixed extraction process of a certain second manufacturer, the wood pulp is pre-crushed to about 1.0*1.0cm and mixed into the flake storage cabinet, and then enters the high-consistency pulper and mixed pulper together with the flakes; due to the lack of the necessary separate combing process of the wood pulp, the uniformity of the wood pulp in the mixed pulp is poor, resulting in its squeezed dryness is still not as good as the process of separate pre-combination of the wood pulp. However, it is better than that of manufacturer one, with the last squeezed dryness of the mixed extraction at 32.0%±1.5%, the concentration of the first-stage extract is 7.5%-8.0%, the relative extraction rate of the tobacco stem pre-extraction is 50%-55%, and the relative extraction rate of the third-stage extraction is 82%-84%.

[0060] Although the relevant parameter data of a certain third-party manufacturer are basically the same, its equipment layout is more complicated, and there are a series of problems such as excessive material accumulation on the extraction spiral, difficulty in cleaning, unsatisfactory mixing effect, and liquid leakage.

[0061] A certain fourth manufacturer cut off the tobacco stems, which seriously damaged the length of the fiber material in the tobacco stems. In order to maintain the improvement and stability of the extraction and squeezing dryness, the proportion of wood pulp used was generally 13%-15%, resulting in a higher content of wood pulp fiber in the final tobacco sheet product, and the final product's taste retention was not as good as Example 1.

[0062] The above embodiments are merely illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. Anyone familiar with the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by a person of ordinary skill in the art without departing from the spirit and technical concept disclosed by the present invention shall still be covered by the claims of the present invention.

Claims

1. A semi-separated and semi-combined mixed countercurrent extraction process for papermaking tobacco flakes, characterized in that: The following steps are involved: 1) Tobacco stem pre-extraction: adding extraction hot water, heated stem liquid, and tobacco stems to a tobacco stem pulper, mixing and stirring to obtain a mixed material 1; vibrating and screening the mixed material 1 to obtain extracted tobacco stems and free liquid; defibration processing the extracted tobacco stems, and performing solid-liquid separation on the defibration material to obtain pre-extracted tobacco stems and a liquid phase; 2) Mixed extraction and pulping: adding the secondary extraction liquid, the primary extraction liquid, wood pulp, flakes and pre-extracted tobacco stems into a mixed pulper, mixing and stirring to obtain an extraction material 1; 3) Continuous extraction: the extracted material is subjected to primary squeezing to obtain primary squeezed material and primary extraction liquid, the primary squeezed material is sent to a secondary mixing pump to be mixed with a tertiary extraction liquid, the secondary extraction is subjected to secondary squeezing to obtain a secondary squeezed material and a secondary extraction liquid, the secondary extraction liquid is returned to the secondary squeezed material and sent to a tertiary mixing pump to be mixed with hot extraction water, the tertiary extraction is subjected to tertiary squeezing to obtain a tertiary squeezed material and a tertiary extraction liquid, the tertiary squeezed material is mixed with diluted white water and then transported to the pulping section; wherein, the primary extraction liquid and the secondary extraction liquid are returned to the mixing pulper, and the tertiary extraction liquid is returned to the secondary mixing pump.

2. The semi-separated and semi-combined mixed countercurrent extraction process for paper-making tobacco sheets according to claim 1, characterized in that: Step 1) includes one or more of the following features: (1a) When starting the tobacco stem pulper, add extraction hot water and heated stem liquid simultaneously, and then add tobacco stems; (1b) Based on absolute dry material, the total volume of hot water for extraction and heated stem liquid added for every 100 kg of tobacco stems is 0.55-0.65 m 3 , the volume of hot water for extraction accounts for 55% to 65%, and the volume of heated stem liquid accounts for 35% to 45%; (1c) The mixing and stirring time is 15 to 25 minutes; (1d) the dryness of the tobacco stems after extraction is 12% to 17%; (1e) The dryness of the pre-extracted tobacco stems is 33% to 37%.

3. The semi-separated and semi-combined mixed countercurrent extraction process for paper-making tobacco sheets according to claim 1, characterized in that: Step 2) includes one or more of the following features: (2a) Adding secondary extract, primary extract, wood pulp, flakes and pre-extracted tobacco stems to the mixer pulper. The specific operation includes: when starting the mixer pulper, adding the secondary extract and the primary extract at a constant flow rate, when the amount of the secondary extract and the primary extract reaches 20 to 25 times the weight of the wood pulp, adding the wood pulp, stirring for 3 to 8 minutes, and when the addition of the secondary extract and the primary extract is complete, adding the flakes and pre-extracted tobacco stems; (2b) based on absolute dry material, the mass ratio of the added flakes to the mass ratio of the tobacco stems added in step 1) is 40-60:40-60; based on absolute dry material, the weight of the wood pulp added for every 100 kg of tobacco stems and flakes is 9-11 kg; (2c) Based on the absolute dry material, the total volume of the secondary extract and the primary extract added for every 100 kg of tobacco stems and flakes is 0.55-0.65 ml 3 , wherein the volume proportion of the secondary extract is 55% to 65%, and the volume proportion of the primary extract is 35% to 45%; (2c) The mixing and stirring time is 15 to 25 minutes.

4. The semi-separated and semi-combined mixed countercurrent extraction process for paper-making tobacco sheets according to claim 1, characterized in that: Step 3) includes one or more of the following features: (3a) The processing efficiency of the first-stage squeezing, the second-stage squeezing, and the third-stage squeezing is consistent, and the squeezing dryness is 33% to 37%. The squeezed material of each stage directly falls into the mixing pump of the next stage and mixes with the extraction liquid of the next stage; (3b) Based on absolute dry material, the amount of tertiary extract added to the secondary mixing pump is 0.30-0.40 m3 / s for every 100 kg of tobacco stems and flakes. 3 , the extraction hot water added at the three-stage mixing pump is 0.30~0.40m 3 .

5. A semi-separated and semi-combined mixed countercurrent extraction system for papermaking tobacco sheets, characterized in that: It includes a pre-extraction unit, a mixed extraction unit, and a continuous extraction unit; The pre-extraction unit comprises a tobacco stem pulper (1), a tobacco stem vibrating screening machine (2), a defibrating machine (3) and a tobacco stem squeezing machine (4); the tobacco stem pulper (1) is provided with an extraction hot water inlet, a heating stem liquid inlet, a tobacco stem addition inlet and a mixed material outlet; the tobacco stem vibrating screening machine (2) is provided with a mixed material inlet, a free liquid outlet and a post-extraction tobacco stem outlet, and the mixed material inlet is connected to the mixed material outlet of the tobacco stem pulper (1); the defibrating machine (3) is provided with a post-extraction tobacco stem inlet and a post-fibrating material outlet, and the post-extraction tobacco stem inlet is connected to the post-extraction tobacco stem outlet of the tobacco stem vibrating screening machine (2); the tobacco stem squeezing machine (4) is provided with a post-fibrating material inlet, a post-pre-extraction tobacco stem outlet and a liquid phase outlet, and the post-fibrating material inlet is connected to the post-fibrating material outlet of the defibrating machine (3); The mixed extraction unit comprises a mixed pulper (5) and an extraction buffer tank (6); the mixed pulper (5) is provided with a secondary extraction liquid inlet, a primary extraction liquid inlet, a wood pulp inlet, a pre-extracted tobacco stem inlet, a sheet end inlet and an extraction material outlet; the pre-extracted tobacco stem inlet is connected to the pre-extracted tobacco stem outlet of the tobacco stem squeezer (4); the inlet of the extraction buffer tank (6) is connected to the extraction material outlet of the mixed pulper (5); The continuous extraction unit comprises a primary squeezer (7), a primary extraction liquid tank (8), a secondary mixing pump (9), a secondary squeezer (10), a secondary extraction liquid tank (11), a tertiary mixing pump (12), a tertiary squeezer (13), a tertiary extraction liquid tank (14) and a pre-extraction mixing pump (22); the primary squeezer (7), the secondary mixing pump (9), the secondary squeezer (10), the tertiary mixing pump (12) and the tertiary squeezer (13) are connected in sequence; the primary squeezer (7) is provided with an extraction material inlet and a primary extraction liquid outlet, the extraction material inlet is connected with the outlet of the extraction buffer tank (6), the secondary mixing pump (9) is provided with a tertiary extraction liquid inlet The secondary extruder (10) is provided with a secondary extraction liquid outlet, the tertiary mixing pump (12) is provided with an extraction hot water inlet, the tertiary squeezing machine (13) is provided with a tertiary squeezed material outlet and a tertiary extraction liquid outlet, and the tertiary squeezed material outlet is connected to the pulping section; the inlet of the primary extraction liquid tank (8) is connected to the primary extraction liquid outlet of the primary squeezing machine (7), and the outlet is connected to the primary extraction liquid inlet of the mixing pulper (5); the secondary extraction tank (11) is connected to the secondary extraction liquid outlet of the secondary squeezing machine (10) and the secondary extraction liquid inlet of the mixing pulper (5); the tertiary extraction tank (14) is connected to the tertiary extraction liquid inlet of the secondary mixing pump (9).

6. The paper-making tobacco sheet half-split and half-combined mixed countercurrent extraction system according to claim 5, characterized in that: The volume of the extraction buffer tank (7) is 1.3 to 1.5 times the mixing volume of the mixer pulper (5).

7. The semi-separated and semi-integrated mixed countercurrent extraction system for paper-making tobacco sheets according to claim 5, characterized in that: A pre-extracted tobacco stem buffer bin (19) is provided on the connecting pipeline between the tobacco stem squeezer (4) and the mixer pulper (5); the feed inlet of the pre-extracted tobacco stem buffer bin is connected to the pre-extracted tobacco stem outlet of the tobacco stem squeezer (4); and the discharge outlet of the pre-extracted tobacco stem buffer bin (19) is connected to the pre-extracted tobacco stem inlet of the mixer pulper (5).

8. The semi-separated and semi-integrated mixed countercurrent extraction system for paper-making tobacco sheets as claimed in claim 5, characterized in that: It also includes an extraction hot water tank (16), which is provided with an outlet 1 and an outlet 2, wherein the outlet 1 is connected to the extraction hot water inlet of the tobacco stem pulper (1) of the pre-extraction unit, and the outlet 2 is connected to the extraction hot water inlet of the three-stage mixing pump (12) of the continuous extraction unit.

9. The semi-separated and semi-integrated mixed countercurrent extraction system for paper-making tobacco sheets as claimed in claim 5, characterized in that: The pre-extraction unit also includes a stem liquid collecting tank (19) and a stem liquid heating tank (20); the stem liquid collecting tank (19) is provided with a free liquid inlet, a squeezer liquid phase inlet and a stem liquid outlet, the free liquid inlet is connected to the free liquid outlet of the tobacco stem vibrating screening machine (2), and the squeezer liquid phase inlet is connected to the liquid phase outlet of the tobacco stem squeezer (4); the stem liquid heating tank (20) is provided with a stem liquid inlet and a heated stem liquid outlet, the stem liquid inlet is connected to the stem liquid outlet of the stem liquid collecting tank (19), and the heated stem liquid outlet is connected to the heated stem liquid inlet of the tobacco stem pulper (1).

10. The paper-making tobacco sheet half-split and half-combined mixed countercurrent extraction system according to claim 5, characterized in that: The secondary mixing pump (9) and the tertiary mixing pump (12) both use high-concentration solid-liquid mixing screw pumps; and / or the pre-knock mixing pump (22) uses a medium-concentration solid-liquid mixing screw pump.

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