A device and method for purifying and concentrating a tobacco extract

Abstract

This invention discloses a device and method for purifying and concentrating tobacco extract. The device includes a ceramic membrane module for filtering the tobacco extract, with its outlet connected to an MVR (Medium-Voltage Reduction) concentrator for concentrating the tobacco extract. The condensate outlet of the MVR concentrator is connected to a reverse osmosis membrane module. The tobacco extract enters the ceramic membrane module to remove suspended macromolecular substances. The purified tobacco extract then enters the MVR concentrator for concentration and dehydration, increasing its density and solids content. The condensate from the MVR concentrator enters the reverse osmosis membrane module to recover the tobacco aroma components. The product recovered by the reverse osmosis membrane module is combined with the tobacco concentrate from the MVR concentrator and collected centrally. This invention reduces the loss of heat-sensitive substances in the extract, retains the aroma components in the tobacco extract, and simultaneously achieves the required solids content and density of the obtained tobacco concentrate for subsequent coating processes.

Description

Technical Field

[0001] This invention relates to a device and method for purifying and concentrating tobacco extract, belonging to the field of reconstituted tobacco production. Background Technology

[0002] The papermaking process for reconstituted tobacco is a crucial technology in the tobacco industry and an important way to comprehensively utilize waste tobacco raw materials. It involves first extracting one or more raw materials—tobacco fragments, tobacco dust, or tobacco stems—using a solvent, then separating the solid and liquid components using a screw press. The solid pulp is then beaten and refined before being formed into a base sheet using a paper machine. Simultaneously, the tobacco extract is combined, purified, and concentrated under reduced pressure to obtain a concentrated tobacco liquid. Finally, this concentrated liquid is coated onto the base sheet, dried, and slit to produce reconstituted tobacco leaves.

[0003] Currently, most domestic papermaking-based reconstituted tobacco production processes primarily employ traditional filtration methods for tobacco extract liquor purification, such as using vibrating screens or horizontal screw centrifuges. However, these methods fail to effectively remove suspended fine particles and large molecules like proteins and starches. Poor extraction results in increased scaling in the evaporator during concentration, sticky and clumping surfaces after coating, and a higher concentration of insoluble fine particles and large molecules negatively impacts the sensory quality of reconstituted tobacco (e.g., strong off-flavors, poor taste). Therefore, to reduce the content of proteins, pectin, and other large molecules in the extract and improve the sensory quality of reconstituted tobacco, advanced pretreatment of tobacco extract liquor using novel purification methods is urgently needed.

[0004] Membrane filtration technology has been gradually applied to the purification process of tobacco extract. Its working principle utilizes the mechanical sieving effect of micropores on the membrane surface to separate substances of different particle sizes, achieving the purpose of separation and impurity removal. Compared with mechanical filtration methods such as sieves, horizontal spiral centrifuges, and disc sieves, membrane filtration offers higher filtration precision, with membrane pore sizes reaching the micrometer or even nanometer scale.

[0005] In addition, in the production process of reconstituted tobacco using the papermaking method, after the tobacco extract is filtered and purified, a mature evaporation and concentration process is generally used to prepare tobacco concentrate. The concentration method commonly employs negative pressure steam boiling, which condenses and discharges the evaporated water and volatile substances, thereby achieving the purpose of extract concentration. However, these methods suffer from problems such as high concentration temperature, long concentration time, loss of effective components, low concentration efficiency, high energy consumption, and high operating costs. Patents CN102823935A, CN101708063A, and CN103349351A propose the use of single-stage / multi-stage nanofiltration (NF) or reverse filtration (RO) membrane concentration processes, but these have not been widely adopted in the industry due to their low concentration ratio and membrane fouling issues. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to provide a highly efficient and low-consumption tobacco extract purification and concentration device and method.

[0007] To address the aforementioned problems, the present invention provides a tobacco extract purification and concentration treatment device, which includes a ceramic membrane module for filtering the tobacco extract, an outlet of the ceramic membrane module connected to an MVR concentration device for concentrating the tobacco extract, a condensate outlet of the MVR concentration device connected to a reverse osmosis membrane module, and both the MVR concentration device and the reverse osmosis membrane module having a tobacco concentrate outlet.

[0008] Preferably, the ceramic membrane module includes a centrifugal device, a filtration device, and an automatic backwashing device. The ceramic membrane module features high separation accuracy, temperature resistance, and fouling resistance. The MVR (Mechanical Vapor Recompression Evaporator) concentrate unit offers high evaporation efficiency at low temperatures and low energy consumption.

[0009] Preferably, the inner membrane of the ceramic membrane assembly is made of alumina or silicon carbide, and the pore size on the membrane is 20-200 nm, preferably 40-100 nm.

[0010] This invention also provides a method for purifying and concentrating tobacco extract, wherein the tobacco extract enters a ceramic membrane module to remove suspended solids and macromolecular substances; the purified tobacco extract then enters an MVR (Medium-Voltage Reduction) concentrator for concentration and dehydration to increase the density and solid content of the tobacco concentrate; the condensate generated by the MVR concentrator enters a reverse osmosis membrane module to recover the tobacco aroma components therein; the product recovered by the reverse osmosis membrane module is combined with the tobacco concentrate generated by the MVR concentrator and collected centrally.

[0011] Preferably, the macromolecules include at least one of protein, pectin, and starch.

[0012] Preferably, the ceramic membrane module is a rotary ceramic membrane module with a rotation speed of 100-1000 rpm, preferably 300-800 rpm; the filtration pressure inside the rotary ceramic membrane module is controlled at 50-500 kPa.

[0013] Preferably, the tobacco extract has a residue content of 0.1-0.5 wt%; the tobacco extract treated with the ceramic membrane module has a residue content of 0.01-0.05 wt%, a viscosity reduction rate of 20-60%, a protein content reduction rate of 10-30%, a pectin content reduction rate of 15-45%, and a starch content reduction rate of 20-60%.

[0014] Preferably, the feed concentration of the tobacco extract in the MVR concentration device is 5–9 wt%, and the density ranges from 1.01 to 1.05 g / cm³.3 The solid content of the discharged tobacco concentrate is 32–36 wt%, and the density is 1.15–1.20 g / cm³. 3 .

[0015] Preferably, the operating pressure of the reverse osmosis membrane module is 1.0 to 3.0 MPa, and the concentration factor is 15 to 25 times.

[0016] This invention organically combines membrane purification filtration with low-temperature concentration and other technologies. While removing impurities such as fibers, particulate matter, proteins and pectin from the extract, it reduces the loss of heat-sensitive substances in the extract, retains the aroma components in the tobacco extract, and the resulting tobacco concentrate has a solid content and density that meet the requirements of the subsequent coating process.

[0017] Based on the characteristics of tobacco extract, this invention employs a rotary ceramic membrane module to remove most of the fine solid residues such as fibers, tobacco fragments, tobacco powder, and tobacco dust from the tobacco extract. Simultaneously, it partially removes large molecular organic impurities such as proteins, pectin, and starch, thereby improving the quality of reconstituted tobacco products. Furthermore, an MVR (Medium-Voltage Reduction) concentrator is used to concentrate the tobacco extract at low temperatures, reducing energy consumption and preserving more of the effective tobacco components. Finally, the condensate generated during the evaporation and concentration process is further concentrated using a reverse osmosis membrane to recover the tobacco aroma components, which are then returned to the tobacco concentrate.

[0018] Compared with conventional tobacco extract processing techniques, this invention has the following advantages:

[0019] 1. Rotary ceramic membrane modules offer superior contamination resistance and higher filtration accuracy compared to the more commonly used tubular ceramic membranes, significantly improving the quality of reconstituted tobacco. This module utilizes a stacking process to combine ceramic membrane sheets layer by layer, resulting in a smaller footprint. Furthermore, the cleaning process is simpler, and installation, disassembly, and operation are more convenient and efficient.

[0020] 2. Mechanical vapor recompression evaporators (MVR) have an evaporation temperature 5-10°C lower than traditional double-effect evaporation and concentration equipment, and reduce energy consumption by more than 10%. This technology reduces the loss of heat-sensitive substances in tobacco extract and fully preserves the aroma components in tobacco extract.

[0021] 3. This patent recovers the effective components of the evaporation condensate, an innovation that is overlooked by many related patents. During the evaporation of tobacco extract, a large number of volatile esters, alcohols, and ketones, among other small molecules, enter the condensate. These aroma substances can be recovered and utilized through a reverse osmosis membrane module, further improving the quality of reconstituted tobacco leaves. Attached Figure Description

[0022] Figure 1A schematic diagram of the tobacco extract purification and concentration device provided by the present invention;

[0023] Figure 2 The process flow diagram of the tobacco extract purification and concentration method provided by the present invention. Detailed Implementation

[0024] To make the present invention more apparent and understandable, preferred embodiments are described in detail below with reference to the accompanying drawings.

[0025] The tobacco extract purification and concentration device provided by this invention is as follows: Figure 1 As shown, it includes a ceramic membrane assembly 1 for filtering tobacco extract, the outlet of the ceramic membrane assembly 1 is connected to an MVR concentrator 2 for concentrating tobacco extract, the condensate outlet of the MVR concentrator 2 is connected to a reverse osmosis membrane assembly 3, and both the MVR concentrator 2 and the reverse osmosis membrane assembly 3 are provided with tobacco concentrate outlets.

[0026] The ceramic membrane module 1 is equipped with a centrifugal device, a filtration device, and an automatic backwashing device. The membrane material inside the ceramic membrane module 1 is alumina or silicon carbide, and the pore size on the membrane is 20-200 nm.

[0027] The rotary ceramic membrane module described in each embodiment is a GCM-PFC-05 type rotary ceramic membrane device (Xiamen Guochu); the MVR evaporator is an MVR-002-075-LX-JM type MVR device (Jiangsu Leke); and the HMF type membrane separation and filtration system device (Hefei Geyun).

[0028] Example 1

[0029] This invention provides a method for purifying and concentrating tobacco extract, the process parameters and treatment effects of which are as follows:

[0030] (1) The membrane material of the rotary ceramic membrane module in the membrane filtration unit is alumina, and the pore size of the ceramic membrane is 20nm. The rotation speed of the rotary ceramic membrane module is 100rpm, and the filtration pressure is controlled at 50kPa. The residue content of the tobacco extract before filtration is 0.5wt%. After purification by the rotary ceramic membrane module, the residue content of the tobacco extract is reduced to 0.01wt%. The viscosity of the tobacco extract is reduced by 60%. The protein content is reduced by 30%. The pectin content is reduced by 45%. The starch content is reduced by 60%. The retention rate of conventional chemical components such as total nicotine, total sugar, and total chlorine is 5%.

[0031] (2) The low-temperature concentration unit uses a mechanical vapor recompression evaporator (MVR) to concentrate and dehydrate the purified tobacco extract. The feed concentration of the tobacco extract in the MVR concentration unit is 5 wt%, and the density is 1.01 g / cm³. 3The solid content of the tobacco concentrate from the MVR (Medium-Vitamin Batch Reduction) product ranges from 32 wt%, corresponding to a density increased to 1.15 g / cm³. 3 .

[0032] (3) The effective component recovery unit of evaporation condensate uses a reverse osmosis membrane module to recover the tobacco aroma components in the condensate generated in the MVR concentration unit. The operating pressure range of the reverse osmosis membrane module is 1.0 MPa; the concentration ratio is 15 times.

[0033] Example 2

[0034] This invention provides a method for purifying and concentrating tobacco extract, the process parameters and treatment effects of which are as follows:

[0035] (1) The membrane material of the rotary ceramic membrane module in the membrane filtration unit is silicon carbide, and the pore size of the ceramic membrane is 200 nm. The rotation speed of the rotary ceramic membrane module is 1000 rpm, and the filtration pressure is controlled at 500 kPa. The residue content of the tobacco extract before filtration is 0.1 wt%. After purification by the rotary ceramic membrane module, the residue content of the tobacco extract is reduced to 0.05 wt%. The viscosity of the tobacco extract is reduced by 20%. The protein content is reduced by 10%. The pectin content is reduced by 15%. The starch content is reduced by 20%. The retention rate of conventional chemical components such as total nicotine, total sugar, and total chlorine is 1.5%.

[0036] (2) The low-temperature concentration unit uses a mechanical vapor recompression evaporator (MVR) to concentrate and dehydrate the purified tobacco extract. The feed concentration of the tobacco extract in the MVR concentration unit is 9 wt%, and the density is 1.05 g / cm³. 3 The solid content of the tobacco concentrate from the MVR (Medium-Vitamin Batch Reduction) product ranges from 36 wt%, corresponding to a density increased to 1.20 g / cm³. 3 .

[0037] (3) The effective component recovery unit of evaporation condensate uses a reverse osmosis membrane module to recover the tobacco aroma components in the condensate generated in the MVR concentration unit. The operating pressure range of the reverse osmosis membrane module is 3.0 MPa; the concentration ratio is 25 times.

[0038] Example 3

[0039] This invention provides a method for purifying and concentrating tobacco extract, the process parameters and treatment effects of which are as follows:

[0040] (1) The membrane material of the rotary ceramic membrane module in the membrane filtration unit is alumina, and the pore size of the ceramic membrane is 40nm. The rotation speed of the rotary ceramic membrane module is 500rpm, and the filtration pressure is controlled at 200kPa. The residue content of the tobacco extract before filtration is 0.3wt%. After purification by the rotary ceramic membrane module, the residue content of the tobacco extract is reduced to 0.02wt%. The viscosity of the tobacco extract is reduced by 50%. The protein content is reduced by 25%. The pectin content is reduced by 40%. The starch content is reduced by 50%. The retention rate of conventional chemical components such as total nicotine, total sugar, and total chlorine is 4%.

[0041] (2) The low-temperature concentration unit uses a mechanical vapor recompression evaporator (MVR) to concentrate and dehydrate the purified tobacco extract. The feed concentration of the tobacco extract in the MVR concentration unit is 6 wt%, and the density is 1.02 g / cm³. 3 The solid content of the tobacco concentrate from the MVR (Medium-Vitamin Batch Reduction) product ranges from 33 wt%, corresponding to a density increased to 1.16 g / cm³. 3 .

[0042] (3) The effective component recovery unit of evaporation condensate uses a reverse osmosis membrane module to recover the tobacco aroma components in the condensate generated in the MVR concentration unit. The operating pressure range of the reverse osmosis membrane module is 1.5 MPa; the concentration ratio is 17.5 times.

[0043] Example 4

[0044] This invention provides a method for purifying and concentrating tobacco extract, the process parameters and treatment effects of which are as follows:

[0045] (1) The membrane material of the rotary ceramic membrane module in the membrane filtration unit is alumina, and the pore size of the ceramic membrane is 100nm. The rotation speed of the rotary ceramic membrane module is 750rpm, and the filtration pressure is controlled at 300kPa. The residue content of the tobacco extract before filtration is 0.4wt%. After purification by the rotary ceramic membrane module, the residue content of the tobacco extract is reduced to 0.03wt%. The viscosity of the tobacco extract is reduced by 40%. The protein content is reduced by 20%. The pectin content is reduced by 30%. The starch content is reduced by 40%. The retention rate of conventional chemical components such as total nicotine, total sugar, and total chlorine is 3%.

[0046] (2) The low-temperature concentration unit uses a mechanical vapor recompression evaporator (MVR) to concentrate and dehydrate the purified tobacco extract. The feed concentration of the tobacco extract in the MVR concentration unit is 7 wt%, and the density is 1.03 g / cm³. 3 The solid content of the tobacco concentrate from the MVR (Medium-Vitamin Batch Reduction) product ranges from 34 wt%, corresponding to a density increased to 1.17 g / cm³. 3 .

[0047] (3) The effective component recovery unit of evaporation condensate uses a reverse osmosis membrane module to recover the tobacco aroma components in the condensate generated in the MVR concentration unit. The operating pressure range of the reverse osmosis membrane module is 2.0 MPa; the concentration ratio is 20 times.

[0048] Example 5

[0049] This invention provides a method for purifying and concentrating tobacco extract, the process parameters and treatment effects of which are as follows:

[0050] (1) The membrane material of the rotary ceramic membrane module in the membrane filtration unit is alumina, and the pore size of the ceramic membrane is 150nm. The rotation speed of the rotary ceramic membrane module is 750rpm, and the filtration pressure is controlled at 400kPa. The residue content of the tobacco extract before filtration is 0.4wt%. After purification by the rotary ceramic membrane module, the residue content of the tobacco extract is reduced to 0.04wt%. The viscosity of the tobacco extract is reduced by 30%. The protein content is reduced by 15%. The pectin content is reduced by 20%. The starch content is reduced by 30%. The retention rate of conventional chemical components such as total nicotine, total sugar, and total chlorine is 2%.

[0051] (2) The low-temperature concentration unit uses a mechanical vapor recompression evaporator (MVR) to concentrate and dehydrate the purified tobacco extract. The feed concentration of the tobacco extract in the MVR concentration unit is 8 wt%, and the density is 1.04 g / cm³. 3 The solid content of the tobacco concentrate from the MVR (Medium-Vitamin Batch Reduction) product ranges from 34 wt%, corresponding to a density increased to 1.18 g / cm³. 3 .

[0052] (3) The effective component recovery unit of evaporation condensate uses a reverse osmosis membrane module to recover tobacco aroma components from the condensate generated in the MVR concentration unit. The operating pressure range of the reverse osmosis membrane module is 2.5 MPa; the concentration ratio is 22.5 times.

Claims

1. A method for purifying and concentrating tobacco extract, characterized in that, A tobacco extract purification and concentration treatment device is used, which includes a ceramic membrane module (1) for filtering tobacco extract, the outlet of the ceramic membrane module (1) is connected to an MVR concentration device (2) for concentrating tobacco extract, the condensate outlet of the MVR concentration device (2) is connected to a reverse osmosis membrane module (3), and both the MVR concentration device (2) and the reverse osmosis membrane module (3) are provided with tobacco concentrate outlets; the inner membrane of the ceramic membrane module (1) is made of alumina; the pore size of the pores on the inner membrane of the ceramic membrane module (1) is 20~200nm, and the ceramic membrane module (1) is a rotary ceramic membrane module; The tobacco extract enters a ceramic membrane module to remove suspended solids and macromolecules. After impurity removal, the tobacco extract enters an MVR concentration unit for concentration and dehydration to increase the density and solid content of the tobacco concentrate. The condensate generated by the MVR concentration unit enters a reverse osmosis membrane module to recover the tobacco aroma components. The product recovered by the reverse osmosis membrane module is combined with the tobacco concentrate generated by the MVR concentration unit and collected centrally. The tobacco extract has a residue content of 0.1-0.5 wt%; after treatment with the ceramic membrane module, the tobacco extract has a residue content of 0.01-0.05 wt%, a viscosity reduction rate of 20-60%, a protein content reduction rate of 10-30%, a pectin content reduction rate of 15-45%, and a starch content reduction rate of 20-60%; the feed concentration of the tobacco extract in the MVR concentration device is 5-9 wt%, and the density range is 1.01-1.05 g / cm³. 3 The solid content of the discharged tobacco concentrate is 32-36 wt%, and the density is 1.15-1.20 g / cm³. 3 The operating pressure of the reverse osmosis membrane module is 1.0~3.0 MPa; the concentration factor is 15~25 times.

2. The method for purifying and concentrating tobacco extract as described in claim 1, characterized in that, The ceramic membrane module (1) is equipped with a centrifugal device, a filtration device and an automatic backwashing device.

3. The method for purifying and concentrating tobacco extract as described in claim 1, characterized in that, The macromolecules mentioned include at least one of protein, pectin, and starch.

4. The method for purifying and concentrating tobacco extract as described in claim 1, characterized in that, The rotation speed of the rotary ceramic membrane module is 100~1000 rpm; the filtration pressure inside the rotary ceramic membrane module is controlled at 50~500 kPa.

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