WO2010063238A1

WO2010063238A1 - Method for continuously puffing tobacco shred with microwave

Info

Publication number: WO2010063238A1
Application number: PCT/CN2009/075329
Authority: WO
Inventors: 满鸣; 任宏杰; 杨继志; 何常青; 彭黔荣; 邓葵; 张华�; 路兰卿; 宋建军; 解海鸥; 赖东辉; 杨大泉; 刘晓东
Original assignee: 贵州中烟工业有限责任公司; 北京航天试验技术研究所
Priority date: 2008-12-05
Filing date: 2009-12-04
Publication date: 2010-06-10

Abstract

A method for continuously puffing tobacco shred with microwave includes the following steps: soaking the tobacco shred in expanding agent; recovering the expanding agent in the soaking device after soaking; puffing the soaked tobacco shred with a microwave drier, thereby obtaining expanded tobacco shred. The expanding agent contains one component or more than two components selected from the group consisting of C₄-C₁₂alcohol, C₄-C₁₂ketone, C₂-C₁₂halogenated ether, C₃-C₁₂alkane, or C₃-C₁₂alkane substituted with more than two halogen atoms. The filling value of the obtained puffed tobacco shred reaches more than 7.5, the whole rate of the puffed tobacco shred is more than 90%, the moisture content of the puffed tobacco shred is 12.5±0.5%. The tobacco shred is uniformly puffed, and the obtained tobacco shred does not have water stain.

Description

Method for continuously expanding microwave expanded tobacco

BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to an expansion process for the tobacco industry, and more particularly to a tobacco filament expansion process for an organic medium as an expansion medium, and more particularly to a circulation process for tobacco expansion of a low boiling organic medium as an expansion medium. Background technique

Tobacco expansion technology is a new technology that developed rapidly in the late 1960s and early 1970s. After the tobacco is expanded, the filling capacity can be obviously improved, thereby reducing the consumption of the single-box tobacco of the cigarette and reducing the nicotine content in the cigarette. The incorporation of expanded tobacco into the cigarette enhances its combustion performance and thus reduces the tar content in the cigarette. It is estimated that 10% of expanded tobacco in the cigarette can save 7-8% of tobacco, and the tar content of each cigarette can be reduced by about 2mg. Therefore, countries all over the world are competing to develop new tobacco expansion technology and its supporting equipment. .

At present, the most commonly used technologies in the world of tobacco expansion technology are carbon dioxide tobacco expansion technology, freon tobacco expansion technology, and nitrogen tobacco expansion technology, among which carbon dioxide tobacco expansion technology is most commonly used, but carbon dioxide liquefaction temperature, pressure and its natural The state of the gas in the state determines the complexity and cost of the process. Moreover, the carbon dioxide expansion technology has large loss, high equipment repair and maintenance cost, and high production cost; the tobacco aroma loss is large, the dry coke gas is heavy, the smoke is dry, and the filling performance is good, but the problem of high breaking rate causes the winding process. The loss in the medium is also large, and the actual proportion in the cigarette is far lower than the ratio in the formula.

In the tobacco expansion process in which the freon CFC-11 is a swelling agent, there is a gaseous medium or a liquid medium in the prior art impregnation process. Gaseous CFC-11 impregnated cut tobacco, the specific processing method is as follows: 1. Add a certain amount of cut tobacco to the processing tank which has been preheated to above 60 °C. When the processing tank is sealed, vacuum the vacuum sprayer until the tank The internal vacuum reaches O.OlMpa; 2. The CFC-11 liquid in the cold tank is vaporized by the evaporator, and is injected into the processing tank to impregnate the shredded tobacco. When the gas pressure in the processing tank reaches 0.5 MPa, the injection of CFC-11 gas is stopped; When the tobacco in the processing tank is immersed in CFC-11 gas for a certain period of time, the CFC-11 gas is recovered into the hot tank, and then condensed and liquefied in the cold tank; 4. When the CFC-11 gas in the processing tank is recovered, the pressure in the tank is lowered. When it reaches O.llMpa, dry steam with a pressure of 0.35-0.4Mpa is injected into the tank. The tobacco is heated and the cell structure is expanded. The temperature inside the processing tank rises to 93-94 °C. 5. The CFC-11 gas is sent to the cold. In the tank, it is liquefied by spraying with water at 13-15 °C until the vacuum in the processing tank reaches 0.01-0.03 Mpa, and then the vacuum is stopped; 6. The pressure inside the processing tank is gradually restored to normal pressure, and the can lid is opened. The expanded tobacco is taken out, and the expanded tobacco is loosened and cooled by the wind. And sent to the storage room for storage. The tobacco is impregnated with CFC-11 liquid. The specific processing method is as follows: 1. After cutting, the tobacco is metered by a quantitative feeder and a belt scale, and continuously and evenly rotates through the air lock to enter the impregnator; 2. The tobacco is spiraled in the impregnator Advance, impregnated with liquid CFC-11 of a certain temperature and pressure, and sent to the circulating hot air expansion system through the air lock rotary valve; 3. Rapidly gasification of CFC-11 in the tobacco after the impregnated shredded tobacco is transported in the expansion tower , drowning and expanding, the expanded tobacco is discharged into the recirculating drum through the cyclone and the degassing drum; 4. The expanded tobacco is re-moisturized, and the moisture content is increased to the standard range required for the rolling; 5. Recycling of CFC-11 The CFC-11 and water vapor mixed gas recovered from the expansion system and the degassing drum are supplied with a circulation system, compressed and steam condensed, and CFC-11 is cooled to a liquid, and then recycled to the storage tank for recycling.

In the above-mentioned several tobacco filament expansion processes, the tobacco is impregnated with a gas or liquid expansion agent alone, and the weight change of the tobacco after impregnation is not ideal, and the effect of the expanded tobacco obtained is also lacking, in the liquid expansion agent. In the recycling process, the gasified CFC-11 is recycled and reused during the expansion process. The liquid in the processing tank is not purified and recovered. Some impurities in the tobacco can not be taken out by CFC-11, which affects the quality of the expanded tobacco. .

In addition, because the ozone depletion potential of Freon has an ODP of 1.0, it has a great destructive effect on the ozone layer. It has been banned internationally. The tobacco industry in China has also been discontinued in 2006 according to international conventions.

The tobacco expansion process mainly adopts a method of expanding the tobacco such as hot steam or a fluidized bed. For example, the patent application CN200510010637 uses water as a medium to heat and humidify the tobacco, and the high moisture tobacco is passed through a high temperature air flow at a temperature of 250 to 360 °C. Accelerated dehumidification promotes the expansion of the tobacco, and the obtained expanded tobacco has poor filling performance and large energy consumption. Microwave technology is mainly used in the tobacco industry at home and abroad. It is mainly used in tobacco and tobacco industry. Patent application 200710025714.8 discloses the process of microwave puffing stems. After immersing the stems in aqueous solution, they are flattened. It is placed in a glassware, and then the glassware is placed in a microwave for expansion. The whole process is batch-type, and it cannot be continuously produced. Summary of the invention

The object of the present invention is to provide a process for continuously preparing tobacco shreds by using microwave expansion, and to use an expansion agent which has the advantages of good environmental protection, such as zero ODP value, stable chemical property, good permeability, low toxicity and small surface tension, when the tobacco is impregnated. The process conditions in the whole process are mild, the requirements on the equipment are greatly reduced, the cost is reduced by the full recycling of the expansion agent, the whole device is low in energy consumption, high in automation, short in expansion period, and can be continuously mass-produced; The obtained expanded tobacco has almost no loss performance such as good filling property, high silk rate, no water-stained tobacco and tobacco aroma. In order to achieve the object of the present invention, a method for preparing tobacco shreds by continuous microwave expansion is provided, and the technical solution adopted is as follows:

(1) impregnating tobacco with a water content of 15-30% in a swelling agent;

(2) recovering the expansion agent in the impregnation tank after impregnation;

(3) The impregnated shredded tobacco is expanded in a microwave device with a power density of 7-10 KW/m ² to obtain expanded cut tobacco; the expanding agent comprises 4-12 carbon atoms of alcohol, 4-12 carbon atoms Ketone, halogenated ether of 2-12 carbon atoms,

A component of an alkane of 3 to 12 carbon atoms or an alkane of 3 to 12 carbon atoms substituted by 2 or more halogen atoms or a mixture of two or more components.

The swelling agent is preferably an alcohol of 4 to 12 carbon atoms, a halogenated ether of 2 to 12 carbon atoms, an alkane of 3 to 12 carbon atoms or 3 to 12 carbon atoms substituted by 2 or more halogen atoms. A component of an alkane or a mixture of two or more components.

The halogen atom includes a fluorine atom, a chlorine atom or a bromine atom, which is preferably a fluorine atom.

The expansion agent is preferably an alcohol of 4 to 12 carbon atoms, n-pentane, isopentane, hexane, cyclohexane, heptane, octane, difluoroethane, tetrafluoroethane, tetrafluoropropane, One or a mixture of two or more of pentafluoropropane, hexafluoropropane, heptafluoropropane, pentafluorobutane, decafluoropentane or methoxy nonafluorobutane.

The expansion agent is preferably a difluoroethane, tetrafluoroethane, tetrafluoropropane, pentafluoropropane, hexafluoropropane, heptafluoropropane, pentafluorobutane, decafluoropentane or methoxy nonafluorobutane. Or a mixture of two or more.

The expansion agent is more preferably one or a mixture of two or more of tetrafluoroethane, pentafluoropropane, pentafluorobutane, decafluoropentane or methoxy nonafluorobutane.

The boiling point or azeotropic temperature of the expanding agent is 20-8 CTC, which is preferably 20-6 CTC, more preferably 30-4 CTC. The moisture content of the cut tobacco of step (1) is 17%-25%.

The impregnation of the present invention comprises the shredded tobacco in a liquid expansion agent or/and a gaseous expansion agent.

Preferably, the shredded tobacco is immersed in the liquid expansion agent and the gaseous expansion agent, and the tobacco is impregnated by the expansion agent gas and the liquid combination, the liquid expansion agent wets the tobacco, the gaseous expansion increases the pressure in the impregnation tank, and the liquid expansion agent is easy. After infiltrating into the tobacco, the immersion time is shortened, and the weight of the shredded tobacco is increased after immersion, and the filling ability of the shredded tobacco obtained by the expansion is enhanced.

The recovery of the expansion agent in the impregnation tank according to the present invention comprises first recovering the liquid expansion agent into the medium buffer tank, and then rapidly vaporizing the vapor expansion agent, and then gradually cooling the gas expansion agent, and then the gaseous expansion agent after the initial temperature reduction is condensed. The condensate is liquefied; the gaseous expansion agent is initially cooled, and then condensed and liquefied in the condenser.

The impregnated shredded tobacco is transported into a microwave dryer, and the power density of the microwave is preferably 7-10 KW/m ² _; temperature control At 25-120 ° C, it is preferably 80-115 ° C; the expansion time in the microwave cavity is within 30-120 seconds.

The power density according to the present invention refers to the radiation power of the microwave power per unit area of the microwave, that is, the power density = microwave power / microwave cavity area.

For other tobacco expansion methods in the prior art, for example, superheated steam or a higher temperature hot air flow, the tobacco is expanded, and the present invention uses microwave to expand the tobacco, and is carried out at a relatively low temperature, and has no constituents for the expanded tobacco. Adverse effects, at the same time, due to the non-thermal effect of microwave, that is, the tobacco cells and their internal polar molecules are excited by the ultra-high frequency oscillation of the microwave, and the chances of collision and friction between the molecules are greatly increased, resulting in more A lot of aroma substances, cut tobacco without burnt smell, enhanced smoke, and exclusion of impurities; at the same time microwave also has a bactericidal effect, thereby improving the safety of cigarettes and food quality; the impregnated tobacco is subjected to microwave expansion treatment, moisture content 11 -13%, and no water stains or agglomeration.

The present invention uses a non-polar or weakly polar and low boiling point expansion agent in the tobacco shredding process. The shredded tobacco contains a certain amount of moisture before impregnation, and a large amount of expansion agent enters into the tobacco cells during the impregnation process. The invention expands the microwave of the shredded tobacco under the condition of high power density, and the power density is 7-10 KW/m ² . Under this power density, the microwave penetrates into the deep layer of the shredded tobacco, and the polar water molecules move under the action of the high frequency electromagnetic field. Friction between each other produces high heat, the temperature inside the cell rises rapidly, and the low-boiling expander and gaseous water gradually vaporize from the inside to the outside. The inside of the shredded tobacco forms a loose porous shape, and the diffusion rate of the vaporized low-boiling expander at normal pressure is caused. The temperature gradient between the inside and the outside is not very different, and the tobacco can be expanded rapidly and uniformly, and there is almost no medium residue. Because the temperature inside and outside the tobacco is stable during the whole expansion process, there is no damage to the tobacco, and there is no paste smell. If the power density of the microwave is lower than the above value, no matter how the microwave irradiation time is increased, it will not be the expansion of the tobacco, which will only produce the drying effect, or the expansion effect is poor, and the medium residual amount is high; otherwise, if the power is too High, due to the rapid internal heating of the internal tobacco, the temperature gradient inside and outside is large, the water can not spread out well, there are more water stains, and there is also a lake burn.

In the prior art, before the microwave puffing, the shredded tobacco is impregnated with an aqueous solution, and all of the infiltrated tobacco cells are water molecules. In the process of microwave puffing, due to the large amount of water, strong polarity, strong ability to absorb microwaves, a large amount of heat is generated. A part of the water is rapidly vaporized. As the microwave puffing progresses, the inside of the shredded tobacco gradually forms a loose porous shape, the thermal conductivity inside thereof is weakened, the temperature gradient inside and outside the tobacco is increased, and under the external conditions of normal temperature and normal pressure, the tobacco in the tobacco The water diffusion rate is slow, which results in the moisture of the outer layer of tobacco not being well vaporized. The obtained expanded cut tobacco contains water stains and agglomeration; the temperature inside the cut tobacco is relatively high, and the temperature inside the cut tobacco is relatively high, and there is a paste smell; and the expansion of the cut tobacco is not uniform.

The frequency of the microwave is 2450 MHz. The preferred method for impregnating the tobacco shred in the present invention comprises: adding the treated shredded tobacco, vacuuming, and then injecting the tobacco expansion agent, wherein the liquid expanding agent is injected first, and then the gaseous expanding agent is injected, and the shredded tobacco is expanded in gas and liquid. Dipping in the agent.

Tobacco is added to the impregnation apparatus maintained at a temperature of 65 ° C to 75 ° C.

The vacuuming is to reduce the pressure to 0.05Mpa~0.005Mpa.

The injection of the liquid expansion agent is carried out by spraying from the top of the tobacco. By this filling method, the liquid expansion agent with a small amount is used to wet the tobacco layer layer by layer, and then the gravity expansion agent is used to flow into the impregnation device through the whole tobacco. In the process of exposing the expander, in addition to being able to wet the shredded tobacco, the expansive agent can remove impurities from the surface layer of the shredded tobacco, improve the quality of the shredded tobacco, and reduce the amount of the expanding agent, and the required liquid expanding agent in the shredded tobacco The weight ratio is 0.5-1:1.

The gaseous expansion agent is injected so that the pressure in the impregnation apparatus reaches 0.1 MPa to 1 MPa, and the temperature is 65 to 120 ° C, which is preferably 75 to 110 ° C.

The pressure in the impregnation apparatus is preferably from 0.3 to 0.9 Mpa, more preferably from 0.5 to 0.8 Mpa.

The tobacco is impregnated for 5 min to 30 min under the above pressure and temperature conditions.

The mass ratio of the liquid expansion to the gaseous expansion agent injected into the impregnation apparatus is 1: 0.5-2, which is preferably 1: 0.8-1.5. The cut tobacco has a moisture content of 20% ± 1.

In the present invention, the impregnation process uses a gas-liquid two-form expansion agent to impregnate the shredded tobacco. In the prior art, for example, the expansion agent CFC-11 is impregnated with a gaseous CFC-11 impregnation or a liquid CFC-11, if only liquid expansion is used. Immersion, liquid expansion agent gasification into the tobacco cells, the pressure of the impregnation equipment is completely dependent on the impregnation equipment to provide heat, so the pressure rises slowly, the pressure balance takes a long time, which is not conducive to the improvement of production efficiency; similarly, if only the gaseous state is adopted When the expansion agent is impregnated, the pressure of the impregnation device rises rapidly, and the swelling agent molecules can quickly penetrate into the tobacco cells, but the time of filling the gaseous expansion agent is too long, which is also unfavorable for the improvement of production efficiency. The invention adopts the combination of the gas liquid expansion agent to add the impregnated tobacco, the liquid is wet, the gas is pressurized, the filling time is short, and the production efficiency is high.

In the prior art method of carbon dioxide expanded cut tobacco, most of the impregnation process involves the addition of liquid carbon dioxide and gaseous carbon dioxide. For example: "Tobacco Science and Technology", No. 3, 1997, "Several modified C0 ₂ expanded tobacco process", specific methods: 1 Tobacco is first filled into a mixing tank, vacuum is used to remove air. Then, a certain amount of liquid C0 ₂ is introduced to expand in the tank to form a C0 ₂ cold mist of gas and solid phase mixing, and the mixture is stirred to uniformly mix the cold mist and the tobacco, the temperature of the cut tobacco is lowered to -70 to -85 ° C, and then the impregnation is input. 2; a saturated CO ₂ gas having a pressure of 2.5 to 3.5 MPa is supplied to the impregnator; 3 the impregnator is rapidly decompressed, the shredded tobacco is discharged, and the expansion is sent.

In the process of carbon dioxide expanded tobacco, carbon dioxide at normal temperature, normal pressure is gaseous, and three-phase diagram from carbon dioxide Analysis, carbon dioxide can only exist in liquid form under the pressure of 0.5MPa or more under certain temperature conditions. The technical solution disclosed in "Several modified C0 ₂ expanded tobacco process" firstly introduces liquid carbon dioxide, at -70~ - 85 ° C, mainly in the form of gas-solid, and the tobacco infusion mainly enters the tobacco cells by the liquid expansion agent, and then the liquid in the tobacco cells is vaporized by various expansion methods, but the tobacco is expanded. If gaseous carbon dioxide is not added, gas and solid carbon dioxide can not enter the tobacco cells well. Therefore, a certain pressure of carbon dioxide can be added to pressurize the gaseous carbon dioxide or melt the solid carbon dioxide into liquid carbon dioxide and enter the tobacco cells. The purpose of the later added carbon dioxide is to liquefy the carbon dioxide in the impregnation tank. In the prior art carbon dioxide expanded tobacco process, the gas and liquid phase combination methods are used in the filling method, so that in order to liquefy the carbon dioxide, the pressure required for liquefaction is high, and the gas and liquid combination method of the present invention is filled. The expansion agent is essentially different. In the tobacco impregnation process of the present invention, the boiling point of the bulking agent is far lower than that of carbon dioxide under normal temperature and normal pressure, and there is an essential difference in performance. The first filling liquid is wet tobacco, and then the gaseous expansion agent is mainly pressurized. More expander molecules are introduced into the tobacco cells to improve the impregnation effect and shorten the immersion time.

The temperature of the impregnation of the present invention is controlled at 65-120 ° C, which is preferably 75-110 ° C. If the temperature is too high, the cut tobacco has a burnt smell, affecting the taste of the cigarette, the temperature is too low, the impregnation effect is not good; the impregnation pressure is preferred Controlled at 0.1Mpa~lMpa, the pressure resistance of the equipment is low, and the breaking rate of the shredded tobacco is low, that is, the whole yarn rate is over 90%. Under the impregnation pressure, temperature and time process conditions of the present invention, the fill value of the shredded tobacco obtained after expansion is higher than 7.5.

The expansion agent after the tobacco shreds of the present invention adopts the method for recovering liquid disclosed in the prior art.

Preferably, the method for recovering the expansion agent after the tobacco shred is: recovering and vaporizing the liquid expansion agent in the impregnation device, and the vaporized expansion agent is further condensed into a liquid state after preliminary cooling, and the condensed expansion agent is stored. The tank is recycled; the recovery of the gaseous expansion agent in the impregnation apparatus comprises preliminary cooling of the gaseous expansion agent in the impregnation apparatus and further condensation into a liquid state, and the condensed expansion agent storage tank is recycled.

The gas expansion agent volatilized during the microwave expansion is further cooled and then further condensed into a liquid for recycling. The preliminary cooling includes introducing a gaseous expansion agent into the aqueous medium to lower the temperature of the gaseous expansion agent, preferably water having a temperature of 65 to 70 °C.

In the preliminary cooling process, not only the temperature of the gaseous expansion agent can be lowered, but also purification can be performed, and the entrained impurities of the gas are removed by the medium water to further purify the expansion agent.

The condensation comprises liquefying the gaseous expansion agent by spraying the aqueous medium in a vertical condenser via a preliminary cooled gaseous expansion agent, preferably at a temperature of 12 to 15 °C.

In the recovery of the liquid expansion agent, it is first vaporized, and the expansion agent is entrained during the impregnation process through the vaporization process. The impurities are removed and the expansion agent is purified.

The recovery of the gaseous expansion agent in the impregnation apparatus includes high pressure recovery, accelerated recovery, and/or ejector recovery.

The high pressure recovery comprises recovering the gaseous expansion agent in the impregnation apparatus to a pressure of from 0.35 to 0.8 MPa.

The accelerated recovery comprises: recovering the remaining gaseous expander in the impregnation apparatus to a pressure of from 0.35 to 0.21 MPa after high pressure recovery of the gaseous expansion agent.

In the accelerated recovery process, the pressure in the impregnation tank is large when the recovery is started. In order to reduce the impact on the equipment, a small-diameter pipeline should be used for recovery. When the pressure is reduced to a certain extent, it is replaced by a large-diameter pipeline to speed up recovery. process. Through this recovery method, the gaseous expansion agent can be sufficiently cooled and condensed. If only the small-mouth pipeline is used for recovery, the recovery time is too long. If only the large-diameter pipeline is used for recovery, the gaseous expansion agent cannot be sufficiently cooled and condensed, resulting in The recycling is not complete.

The ejector recovery includes recovering the remaining gaseous expansion agent in the impregnation apparatus after accelerated recovery to a pressure of 0.1-0.11 MPa.

The ejector recovery recovers the gas in the impregnation apparatus by an ejector pump.

In the high pressure recovery, accelerated recovery and ejector recovery process, the gaseous expansion agent from the impregnation equipment is first cooled, then condensed into a liquid expansion agent, and the storage tank is recycled.

After condensation, the liquid expansion agent is incompatible with water. After standing, the liquid is layered, the upper layer is water, the lower layer is liquid expansion agent, the lower layer of liquid expansion agent is then impregnated with shredded tobacco, and the upper layer of water is cooled and recycled. Use a cooled, condensed gaseous expander.

The method for recovering the tobacco filler of the invention is characterized in that the liquid expansion agent which is discharged from the impregnation tank is well purified through the recovery device, and at the same time, some impurities in the tobacco can be removed, and the taste is improved; the liquid and gaseous state are obtained through many ways. The expansion agent is recycled, and the cooling water used can also be recycled. This recycling method recycles the expansion agent and water, has little environmental pollution, reduces the industrial cost, and meets the needs of industrialized large-scale production.

The continuous microwave tobacco expansion method of the invention adopts the advantages of stable performance, low toxicity, no damage to the ozone layer, and the use of the microwave expansion technology to expand under normal temperature and pressure, and no damage to the tobacco. No paste, because the temperature is not high, the effective material loss of the expanded tobacco is reduced; the amount of expansion agent in the expanded tobacco is extremely small, the expansion is uniform, there is no water-cured tobacco; compared with the traditional expansion equipment, the heat dissipation of microwave expansion Small size can greatly improve the high temperature working conditions on site; expansion production can be carried out continuously. In particular, the preferred impregnation scheme of the present invention, the gas and liquid expansion agent combined with the filling method impregnate the tobacco, thereby improving the production efficiency, and the indexes of the obtained tobacco after the microwave expansion are high, the filling rate is higher than 7.5, the whole wire The rate is greater than 90%, and the moisture content of the tobacco after expansion is 12.5±0.5%. The wire is zero, and the tobacco does not shrink after expansion, meeting the requirements of the cigarette process.

The invention has great improvement in the process parameters, and the pressure of the impregnation equipment is between 0.1 and 1 MPa. Compared with the impregnation process of other expanded tobacco processing in the prior art, the requirement of the pressure resistance degree of the impregnation equipment is lowered. The expansion process is carried out at normal temperature and normal pressure, and the process of feeding, dipping and expanding from the shredded tobacco is continuously closed, which is in line with the demand of industrial large-scale production. The gas and liquid expansion agent after the tobacco immersion are separately recycled and recycled by different methods, and the immersed expansion agent is purified during the recovery process, so that it can be reused again, and the medium used in the recovery process is also recycled. The energy-saving and energy-saving recycling method reduces the cost of tobacco expansion, has little environmental pollution, meets the requirements of environmental protection development, and conforms to the development trend of tobacco system harm reduction and coke reduction. DRAWINGS

1 is a process flow diagram of continuous microwave tobacco expansion according to the present invention;

Example 1 As shown in Fig. 1, the shredded tobacco was pretreated to have a water content of 15% by weight of the shredded tobacco, and 200 kg of the treated shredded tobacco was added to the impregnation tank which had been preheated to 70 ° C; Vacuum, the pressure is at 0.OlMpa; to the impregnation tank is added lOOKg liquid expansion agent, the expansion agent is made up of 85% pentafluorobutane (1,1,1,3,3-pentafluorobutane), a mixture of 15% heptafluoropropane (1,1,1,2,3,3,3-heptafluoropropene), and then vaporize about 70 Kg of liquid expansion agent into the impregnation tank to increase the pressure in the impregnation tank to 0.8Mpa, the temperature is raised to 110 ° C, immersed for 30 min under the above temperature and pressure conditions; after the tobacco immersion, the gas and liquid expansion agent are separately recovered and reused, and after the recovery is completed, the shredded tobacco is discharged and sent to In the microwave expansion device, the microwave power density is 10 KW/m ² , and the expanded tobacco is obtained by expanding at a temperature of 95-100 ° C under normal pressure for 60 seconds, and the obtained expanded tobacco has a filling value of 8.5 and a water content of 12.5%. The whole yarn rate is 95%.

Example 2

The shredded tobacco is pretreated to have a water content of 17% by weight of the shredded tobacco, and 200 Kg of the treated shredded tobacco is added to the impregnation tank which has been preheated to 65 ° C; the impregnation tank is evacuated to a pressure of 0.03 MPa; 200 Kg of liquid expansion agent was added to the impregnation tank, and the expansion agent was 80% pentafluorobutane (1,1,1,3,3-pentafluorobutane) and 20% pentafluoropropane. (1,1,1,3,3-pentafluoropropane) a mixture of the mixture, then vaporize 200Kg of liquid expansion agent into the impregnation tank, increase the pressure in the impregnation tank to 0.5Mpa, and raise the temperature to 100°. C, immersed for 10 minutes under the above temperature and pressure conditions; after the tobacco immersion, the gas and liquid expansion agent are separately recovered and reused, and after the recovery is completed, the tobacco is discharged and sent to the microwave expansion device, the microwave power density It was 8 KW/m ² , and expanded at a temperature of 76-80 ° C under normal pressure for 100 seconds to obtain expanded cut tobacco. The obtained expanded cut tobacco had a filling value of 8.0, a water content of 12.7%, and a whole filament ratio of 96%.

Example 3

The shredded tobacco is pretreated to have a water content of 25% by weight of the shredded tobacco, and 200 Kg of the treated shredded tobacco is added to the impregnation tank which has been preheated to 75 ° C; the impregnation tank is evacuated to a pressure of 0.005 MPa; Adding 130Kg of liquid expansion to the impregnation tank, the expansion agent is a mixture of 95% pentafluorobutane and 5% hexafluoropropane, and then vaporizing 190Kg of liquid expansion agent into the impregnation tank to make the pressure in the impregnation tank Increase to 0.7Mpa, the temperature rises to 80 ° C, immersed under the above temperature and pressure conditions for 20min; after the tobacco immersion, the gas and liquid expansion agent are separately recycled and reused, after the recovery is completed, the tobacco is discharged, and It is sent into the microwave expansion device, the microwave power density is 7KW/m ² , and the expanded tobacco is obtained by expanding the temperature at 35-40 ° C for 40 seconds under normal pressure. The filling value of the obtained expanded tobacco is 9.0, and the water content is: 12.2%, the whole filament rate is 94%.

Example 4

The shredded tobacco is pretreated to have a water content of 30% by weight of the shredded tobacco, and 200 Kg of the treated shredded tobacco is added to the impregnation tank which has been preheated to 65 ° C; the impregnation tank is evacuated to a pressure of 0.009 MPa; 160 Kg of liquid expansion agent was added to the impregnation tank, and the expansion agent was composed of 80% pentafluorobutane (1,1,1,3,3-pentafluorobutane) and 20% decafluoropentane (1,1). a mixture of 1,2,3,4,4,5,5,5-decafluoropentane), and then vaporize 96Kg of liquid expansion agent into the impregnation tank to increase the pressure in the impregnation tank to 0.1 Mpa The temperature is raised to 75 °C, and immersed for 15 minutes under the above temperature and pressure conditions; after the tobacco is immersed, the gas and liquid expansion agents are separately recovered and reused, and after the recovery is completed, the tobacco is discharged and sent to the microwave. In the expansion equipment, the microwave power density is 9KW/m ² , and the expanded tobacco is obtained by expanding the temperature at 110-120 ° C for 50 seconds under normal pressure. The filling value of the obtained expanded tobacco is 7.9, and the water content is 12.8%. The silk rate is 95%. Example 5

The shredded tobacco is pretreated to have a water content of 20% by weight of the shredded tobacco, and 200 Kg of the treated shredded tobacco is added to the impregnation tank which has been preheated to 70 ° C; the impregnation tank is evacuated to a pressure of 0.03 MPa; Adding 10Ogg liquid expansion agent to the impregnation tank, the expansion agent is 90% pentafluorobutane (1,1,1,3,3-pentafluorobutane), 10% tetrafluoroethane (1,1) , 1,2-tetrafluoroethane) mixture, then vaporize 200Kg of liquid expansion agent into the impregnation tank, increase the pressure in the impregnation tank to l.OMpa, the temperature rises to 120 ° C, at the above temperature Under the pressure condition, immersing for 5 minutes; after the tobacco immersion, the gas and liquid expansion agent are separately recovered and reused. After the recovery, the shredded tobacco is discharged and sent to the microwave expansion device, and the microwave power density is 10KW/m ^{2 .} The expanded tobacco was obtained by expanding at a temperature of 25-30 ° C under normal pressure for 30 seconds, and the obtained expanded tobacco was filled with a value of 8.8, a water content of 12.9%, and a whole filament ratio of 92%.

Example 6

The shredded tobacco is pretreated to have a water content of 20% by weight of the shredded tobacco, and 200 Kg of the treated shredded tobacco is added to the impregnation tank which has been preheated to 70 ° C; the impregnation tank is evacuated to a pressure of 0.03 MPa; Adding 200 Kg of liquid expansion agent to the impregnation tank, the expansion agent consisting of a mixture of 85% pentafluoropropane, 13% pentafluorobutane and 2% perfluorobutyl methyl ether, raising the temperature in the impregnation tank to 110° C, immersed for 70 min under the above conditions; after the tobacco immersion, the gas and liquid expansion agents are separately recovered and reused. After the recovery, the shredded tobacco is discharged and sent to the microwave expansion device, and the microwave power density is 8KW/m. ² , the expanded tobacco was obtained by expanding at a temperature of 77-80 ° C under normal pressure for 50 seconds, and the obtained expanded tobacco was filled with a value of 7.6, a water content of 12.1%, and a whole filament ratio of 92%.

Example 7

The shredded tobacco is pretreated to have a water content of 18% by weight of the shredded tobacco, and 200 Kg of the treated shredded tobacco is added to the impregnation tank which has been preheated to 68 ° C; the impregnation tank is evacuated to a pressure of 0.02 MPa; Then, 180Kg of the liquid expansion agent is vaporized into the impregnation tank, and the expansion agent is a mixture of 95% dichlorofluoroethane and 5% perfluorohexane, and the temperature is raised to 90 ° C under the above conditions. Impregnation for 70 min;

After the tobacco is immersed, the gas and liquid expansion agent are separately recovered and reused. After the recovery, the tobacco is discharged and sent to the microwave expansion device, the microwave power density is 9KW/m ² , and the temperature is 95-100°. C. The expanded tobacco was obtained by expansion treatment under normal pressure for 40 seconds, and the obtained expanded tobacco was filled with a value of 7.8, a water content of 12.9%, and a whole filament ratio of 91%. Example 8

The shredded tobacco is pretreated to have a water content of 25% by weight of the shredded tobacco, and 200 Kg of the treated shredded tobacco is added to the impregnation tank which has been preheated to 75 ° C; the impregnation tank is evacuated to a pressure of 0.005 MPa; 130Kg of liquid expansion was added to the impregnation tank, and the expansion agent was 80% pentafluorobutane (1,1,1,3,3-pentafluorobutane) and 20% decafluoropentane (1,1,1). a mixture of 2,3,4,4,5,5,5-decafluoropentane), and then vaporize 190 Kg of liquid expansion agent into the impregnation tank to increase the pressure in the impregnation tank to 0.7 MPa, and the temperature rises. Up to 80 ° C, immersed under the above temperature and pressure conditions for 20 min _;

After the tobacco is immersed, the liquid expansion agent is recovered into the medium buffer tank, and is rapidly heated and vaporized. After the preliminary purification, the gaseous expansion agent is introduced into the hot tank containing water, and the gaseous expansion agent from the hot tank is passed to the condenser. Condensate, condense and liquefy with cold water, place the mixture in the condenser in the medium storage tank, stratify the water and the expansion agent, and finally the lower expansion agent enters the medium measuring tank for recycling, and the upper water is cooled by the freezer. After recycling;

After the liquid medium is recovered, the gaseous expansion agent in the impregnation tank is driven into the hot tank containing 70 ° C water through the pipeline, the gaseous expansion agent is initially cooled and purified, and then passed to the condenser to condense, from the top of the condenser. The temperature of the sprayed water is 12 °C. The liquefied expander and part of the water are stored in the medium storage tank. In the medium storage tank, the water is stratified with the expansion agent, and the lower layer of the expansion agent finally enters the medium measuring tank for recycling. The upper layer water is refrigerated by the freezer and recycled until the pressure of the impregnation tank reaches 0.54 Mpa; then the gaseous expansion agent in the impregnation tank is quickly passed through the small-diameter and large-diameter two-way recovery route to 70 ° C. The hot water tank, the gaseous expansion agent is returned to the condenser for condensation, the medium storage tank is stored, and finally enters the medium measuring tank for recycling until the pressure in the impregnation tank reaches 0.28 Mpa; finally, the impregnation tank is recovered by the ejector pump. The remaining gas reduces the pressure in the impregnation tank to an atmospheric pressure, and the recovered residual gas quickly enters the hot tank, and the water vapor in the hot tank is condensed and accumulated. Hot tank, after a preliminary cooling medium is a gaseous environment, into the condenser is condensed, media storage tank, and finally into the metering tank medium recycled;

After the tobacco is impregnated, the gas and liquid expansion agents are separately recovered and reused. After the recovery, the shredded tobacco is discharged and sent to the microwave expansion device, the microwave power density is 9KW/m ² , and the temperature is 40-45°. C. Expansion treatment under normal pressure for 40 seconds to obtain expanded tobacco, the filling value of the obtained expanded tobacco was 8.4, the water content was 12.6%, and the whole filament ratio was 96%. Example 9-1 2

Examples 9-12 except for the expansion agent used, other parameters were used in Example 1. The selection of the expansion agent and the performance parameters of the final expanded tobacco were as follows:

a mixture of a mixture of alkane, pentafluorobutane, methoxy, nonafluorobutane, and a mixed mixture of ethane. Filling value 8.2 7.5 7.9 8.4 Water content 12.8% 12.3% 12.8% 12.2% Filament rate 92 % 93.4% 94% 92.6%

Claims

Claim

A method for continuously expanding microwave shredded tobacco, comprising the steps of:

(1) impregnating tobacco with a water content of 15-30% in a swelling agent;

(2) recovering the expansion agent in the impregnation tank after impregnation;

2. A method according to claim 1 wherein said impregnating comprises shredded tobacco in a liquid expansion agent or / and a gaseous expansion agent; preferably the tobacco is impregnated in a liquid expansion agent and a gaseous expansion agent.

3. Method according to claim 1, characterized in that the temperature in the microwave device is controlled at 25-120 ° C, preferably 80-115 ° C.

4. A method according to any one of claims 1 or 3 wherein the cut tobacco is expanded for a period of 30-120 seconds in the cavity of the microwave device.

5. The method of claim 1 wherein the frequency of the microwave is 2450 MHz.

6. The method according to claim 2, wherein when the shredded tobacco is immersed in the liquid expansion agent and the gaseous expansion agent, the liquid expansion agent is first injected into the impregnation device, and then the gaseous expansion agent is injected, and the cut tobacco is injected. Immersed in a gas or liquid expansion agent.

The method according to any one of claims 2 or 6, characterized in that the temperature of the shredded tobacco in the impregnation apparatus during the impregnation is 65-120 ° C, preferably 75-110 ° C.

The method according to any one of claims 2, 6 or 7, characterized in that the pressure of the shredded tobacco in the impregnation apparatus during the impregnation is from 0.1 Mpa to 1 Mpa, preferably from 0.3 to 0.9 Mpa, more preferably 0.5-0.8 Mpa.

9. The method of claim 1 wherein said recovering agent comprises a method of recovering liquid as disclosed in the prior art.

The method according to any one of claims 1 to 9, wherein the recovery of the expansion agent comprises: recovering and vaporizing the liquid expansion agent in the impregnation apparatus, and expanding the gasification agent After preliminary cooling, it is further condensed into a liquid state, and the condensed expansion agent storage tank is recycled; the recovery of the gaseous expansion agent in the impregnation apparatus includes preliminary cooling of the gaseous expansion agent in the impregnation apparatus and further condensation into a liquid state, and expansion after condensation. The tank is recycled.