CN1180729C

CN1180729C - Tobacco thred expansion method and equipment

Info

Publication number: CN1180729C
Application number: CNB011318538A
Authority: CN
Inventors: 黄嘉i; 黄嘉礽
Original assignee: Individual
Current assignee: Individual
Priority date: 2001-12-21
Filing date: 2001-12-21
Publication date: 2004-12-22
Anticipated expiration: 2021-12-21
Also published as: CN1426708A

Abstract

The present invention relates to a method and equipment for the expansion of tobacco shreds. Tobacco shreds which are soaked with an expansion medium (such as carbon dioxide) are sent into a steam flow conveying expansion pipeline for expansion and drying, wherein the steam flow conveying expansion pipeline has the initial temperature of 320 DEG C to 380 DEG C and takes superheated steam as a drying medium. A material-to-steam ratio (the ratio of the mass of soaked tobacco shreds to the mass of conveying steam flow) is increased from smaller than 0.17 to 0.25 to 0.30, and circulating steam flow whose moisture content is a fixed value at lower temperature is mixed with conveying steam flow at specific position where the dry base moisture content of tobacco shreds is reduced to 15.0% to 16.5% of the tobacco shreds conveying expansion pipeline. Thus, the temperature of the steam flow in the conveying expansion pipeline can be rapidly reduced to 160 DEG C and even to 140 DEG C so as to prevent the excessive temperature rise of the tobacco shreds. The dry base moisture content of the tobacco shreds after expansion is controlled as 6% to 9%, the filling value of the tobacco shreds is still higher, the fragmentary rate is reduced, fragrant substances in the tobacco shreds can not be greatly reduced, and the scorched flavor can not occur.

Description

Tobacco thred expansion method and equipment

Technical field

The present invention relates to a kind of method of tobacco expanding and adopt the equipment of this method.

Background technology

Pipe tobacco is behind inflating medium (for example carbon dioxide) dipping, and being admitted to superheated steam is that high temperature (320～380 ℃) air-flow of main gas phase is carried in the expansion system and carried out expansion process.Pipe tobacco after the expansion, its expansion rate can reach 100%, can reduce cigarette list case tobacco leaf consumption significantly; The pipe tobacco combustibility is improved, and makes that tar content obviously reduces in the flue gas, and harmful substance is reduced.Therefore expanded cut tobacco technology and equipment are extensively adopted by countries in the world.

Typical DIET (dry-ice expanding pipe tobacco) technology and equipment, be pipe tobacco behind carbonic maceration, through pine silk device, Vibration Storage bin and quantitative feeding, send into high temperature gas flow and carry expansion system to handle, the gasification and obtain expansion fast of the carbon dioxide in the pipe tobacco and moisture.After expanding, the pipe tobacco moisture content is 2%～3%.After this technology was widely adopted, its defective had also appeared to come out, and the back pipe tobacco broken rate that promptly expands is higher, and fragrance matter reduces significantly in the pipe tobacco, even dried-up flavor occurs in the flue gas.

According to the defective of DIET technology and equipment, meeting the tendency many patents occur, improves its technology and equipment.These patents can be divided into two classes: a class is to improve the dipping systems of pipe tobacco, comprises utilizing the atmospheric carbon dioxide tobacco shred immersion and will using more a spot of liquid CO 2 tobacco shred immersion after the pipe tobacco compacting.Can be loose immediately after Jin Zi pipe tobacco draws off like this, there is not the agglomerating caking of pipe tobacco and needs broken problem to occur making by machinery is loose.Another kind of is to improve high-temperature gas to carry expansion system.Patent (CN1174000A) as U.S. RJ RJ Reynolds Tobacco Holdings ,Inc., propose to be the conveying swelling pipeline with circular arc (C shape) pipeline of larger radius of curvature, cross-section of pipeline width and thickness ratio (W/D) are 5～2 rectangle, and diminishing again thickness after pipeline has one to enlarge gradually carries making of expansion process broken to reduce pipe tobacco.But this equipment can make the fragrance matter volatilization in the pipe tobacco more equally, influences tobacco quality.The patent of Co., Ltd. of Japan Tobacco (CN1061328A) is to carry on the swelling pipeline at pipe tobacco the nozzle that several are positioned at ad-hoc location is set, in high temperature gas flow, inject steam or water smoke by nozzle, with the gas flow temperature in the control conveying swelling pipeline, promptly progressively reduce to about 155 ℃ along pipeline by 320 ℃ of initial temperatures, this method can reduce the loss of fragrance matter in the pipe tobacco, can not make and occur dried-up flavor in the flue gas, but the atomizing effect of the steam that injects from each nozzle or water smoke amount and water is all wayward, pipe tobacco moisture content after the expansion is 2%～3%, makes the broken rate of pipe tobacco too high.Mentioned " the tobacco moisture content after the expansion brings up to 6% or higher, can reduce the chemical change of tobacco in the expansion process, for example because of overheated reduced sugar and the alkaloid of losing " in the patent of U.S. Philip Morris (CN1043842C).This is in original DIET expansion drying system, reduces the conclusion after the test of carrying about expanded gas flow initial temperature to 200 ℃.As everyone knows, reduce and carry the expanded gas flow initial temperature, will reduce the filling value (expansion rate) of expanded cut tobacco.

Up to now, utilize superheated vapor to come expanded cut tobacco, no matter adopt which kind of method, desire to try to achieve high expansion rate for drying medium, all be that moisture content of drying base is reduced to 2%～3% in process of manufacture, and then the moisture regain of the pipe tobacco after will expanding is to needed moisture content of drying base 13.6%～14.3%.Processing not only causes pipe tobacco broken rate height like this, in the pipe tobacco fragrance matter loss many, occur dried-up flavor in the flue gas, and be the waste of energy.In fact, when the pipe tobacco moisture content of drying base is reduced to after 8%～9%, continue dry to its filling value and expansion rate not influence substantially.And the pipe tobacco moisture content of drying base is reduced to the constant rate drying period before 8%～9%, and the pipe tobacco temperature is the boiling temperature (100 ℃) of water under the operating pressure, can not cause a large amount of losses of fragrance matter in the pipe tobacco.But, reduce to 2%～3% when being close to adiabatic drying when the pipe tobacco moisture content of drying base, the pipe tobacco temperature is near dry air temperature, dry air temperature is high more, in the pipe tobacco aroma substance loss many more, dried-up flavor is arranged in the flue gas unavoidably, pipe tobacco is also easily made broken.Therefore, prevent that the pipe tobacco temperature is too high in the expansion process, need control pipe tobacco moisture content of drying base to reduce to 8%～9% dry air temperature when following.

Summary of the invention

It is higher to the purpose of this invention is to provide a kind of tobacco expanding rate, but its broken rate is low, and fragrance matter can not reduce in a large number in the pipe tobacco, more can not occur the expanded cut tobacco method and apparatus of dried-up flavor in the flue gas.

The objective of the invention is to realize by the following technical programs: expanded cut tobacco method provided by the invention, be pipe tobacco through behind inflating medium (as the carbon dioxide) dipping, it is that drying medium, initial temperature are that 320 ℃～380 ℃ air-flow is carried and expanded in the expansion system and dry that flow is sent into equably with the superheated vapor.In the drying medium superheated vapor volume generally be set at 7: 3 with the ratio of dry air volume～9: 1.Improve the material-gas ratio (dipping back tobacco quality and the ratio of carrying the expanded gas flow quality) of carrying expansion system, make its material-gas ratio by being increased to 0.2～0.35 less than 0.17.And the pipe tobacco moisture content of drying base has been reduced to 15%～16.5% ad-hoc location in carrying swelling pipeline, with water capacity reach setting value, part circulating current that temperature is lower is sent into carrying expanded gas flow and is mixed, make and carry the expanded gas flow temperature to reduce to 160 ℃, minimumly reduce to 140 ℃ at the expanded cut tobacco discharge pit.Pipe tobacco moisture content of drying base after the expansion is to be controlled in 6%～9% scope, preferably is controlled at 8%～9%.The back pipe tobacco excessive temperature that can prevent from like this to expand raises, and avoids a large amount of losses of fragrance matter in the pipe tobacco, also dried-up flavor can not occur in the flue gas.According to test, when pipe tobacco when moisture content reduces to 2%～3% in expansion process, wherein the fragrance matter of 21 kinds of heterogeneities (as phenmethylol, β benzyl carbinol, isophorone, fragrant ethyl acetone, acetyl pyrrole etc.) average loss reaches 18.8%, and the pipe tobacco broken rate reaches 8%; And moisture content of drying base was reduced to 8%～9% o'clock, and the loss of same fragrance matter has only 6.9%, and the pipe tobacco broken rate is 4%.Improve the material-gas ratio of carrying swelling pipeline, under the condition constant in the air-flow transporting velocity, that initial airflow temperature is identical, can make and carry the expanded gas flow temperature to reduce faster along pipeline.Best material-gas ratio is 0.25～0.3.

From energy-conservation angle, carry expanded gas flow in system, to recycle.Leak out and reason such as carbon dioxide gasification owing to having in the system, superheated vapor volume and the ratio of dry air volume are less than setting value in the recyclegas.In order to keep carrying expansion system running technical data stable, sending into temperature in circulating current is 100 ℃～105 ℃ steam, and controls its flow, and this can make the circulating current water capacity reach setting value, and reduces the circulating current temperature.What deserves to be mentioned is: for the ease of carrying the control of gas flow temperature in the expansion system, also can adopt another kind to make the circulating current water capacity reach setting value, and part circulating current temperature reduce more way.Promptly in this a part of circulating current of combustion furnace heating, send into the steam (being generally 0.7MPa) of normal use; In that a part of circulating current of carrying expanded gas flow to mix, when sending into the steam of normal use, spray into the water smoke about 6%.So that more easily control the gas flow temperature before the feeder.Undoubtedly, spray vapour and injection flow rate all should be controlled.

Expanded cut tobacco equipment provided by the invention, be that air-flow is carried expansion system, comprise quantitative feeding equipment, charging gas lock (6), carry swelling pipeline (5), feeder (3), discharging gas lock (1), blower fan (2), deduster (19), air exhauster (20), steam supply pipe (16), combustion furnace (14) and connecting pipe and control valve.To the B-B section of carrying swelling pipeline (5), be provided with a bypass pipe (10) and control valve (11) at circulating current pipeline (18), being used for water capacity is that the lower circulating current of set-point temperature is delivered to the B-B cross section, mixes with carrying expanded gas flow.

In the capacity of equipment scope, suitably the control valve (15) in the regulating system, (12) and (11) get final product the material-gas ratio of control system, and can regulate through bypass pipe (10) and deliver to the low temperature circulating air flow of carrying swelling pipeline (5) B-B cross section.

Advantage of the present invention is tangible, not only kept is that drying medium carries out advantages such as tobacco expanding rate height, rate of drying that expansion drying brings be fast with the superheated vapor, the more important thing is and avoided a large amount of losses of pipe tobacco fragrance matter in the expansion process, pipe tobacco is made in a large number and is occurred dried-up flavor in the broken and flue gas, can improve the expanded cut tobacco quality.

Description of drawings

Fig. 1 is expanded cut tobacco equipment (being that air-flow the is carried expansion system) schematic diagram of embodiment;

Fig. 2 carries the change curve of expanded gas flow temperature along pipeline under the different material-gas ratio conditions;

Fig. 3 is for carrying in the swelling pipeline relation of gas flow temperature and material-gas ratio when moisture content of drying base reduces to 15%～16.5%.

The specific embodiment

Embodiment 1: as shown in Figure 1, it is closed cycle system that air-flow is carried expansion system.Entered gauge line 9 by the pipe tobacco behind the carbonic maceration from feed bin 8,, send into initial temperature and be 340 ℃ air-flow and carry expansion dryings in the swelling pipeline 5 through belted electronic balance 7 and charging gas lock 6.Pipeline 5 total lengths (3 imports from the A-A cross section to feeder) are 18.0M, and the superheated vapor volume is 8: 2 with the ratio of dry air volume in the air-flow, and the air velocity in A-A cross section is 48.0M/S.Pipe tobacco after the expansion drying is separated from air-flow in feeder 3, is drawn off by gas lock 1.And carry expanded gas flow to discharge by blower fan 2 through pipeline 4.The air-flow fraction that is discharged from enters deduster 19 through control valve 21 and purifies, and enters atmosphere by blower fan 20, or sends into combustion furnace 14 incineration process; Most of air-flow is recycled.The ratio of superheated vapor volume and dry air volume reaches 8: 2 in the circulating current in order to make, and in order satisfy to reduce to carry the requirement of gas flow temperature behind the swelling pipeline 5B-B cross section, sending into temperature by steam supply pipe 16 in recycling air-flow is 100 ℃ steam, by control valve 17 its flows of control.Circulating current after humiture is regulated, about 53% enters combustion furnace 14 through control valve 15 is heated to 340 ℃, sends into swelling pipeline 5 again.About 47% directly through control valve 11 and by-pass 10, sends into the B-B cross section (the B-B cross section is that the low temperature circulating current mixes the place with carrying expanded gas flow) of pipeline 5 and mixes with carrying expanded gas flow, to quicken to reduce the gas flow temperature of feeder 3 inducers.Also be provided with control valve 12 and by-pass 13 thereof in the system, this is stable in order to control the gas flow temperature that enters the A-A cross section.When combustion furnace 14 heated air stream temperature drifts,

adjustable metering valve

12 and 15 suitably reduces some heat air flow, and through pipeline 13 an amount of low temperature circulating current is mixed with heated air stream, makes and carries the expanded gas flow temperature to reach setting value.

When material-gas ratio is 0.3, supplied materials pipe tobacco moisture content of drying base is 26.6%, contain the dry ice amount after pipe tobacco is impregnated and be under 25.0% the condition, carry on the swelling pipeline 5 and reduce to 172.6 ℃, and feeder 3 import department's gas flow temperatures are reduced to 145.5 ℃ near the gas flow temperature before the B-B cross section.

Embodiment 2: setting material-gas ratio is 0.25.63% circulating current enters through control valve 15 and is heated to 340 ℃ in the combustion furnace 14, and the circulating current of sending into conveying swelling pipeline 5,37% is again sent into the B-B section of carrying swelling pipeline 5 and mixed with carrying expanded gas flow directly through control valve 11 and by-pass line 10.Remaining technology condition is identical with embodiment 1, be that the steam temperature that steam pipe 16 is supplied with is 100 ℃, supplied materials pipe tobacco moisture content of drying base is 26.6%, containing the dry ice amount behind the pipe tobacco dipping is 25%, carrying swelling pipeline 5A-A cross section air velocity is 48M/S, and the superheated vapor volume is 8: 2 with the ratio of dry air volume in the air-flow.At this moment, carrying on the swelling pipeline 5 near the gas flow temperature before the B-B cross section is 194.3 ℃, and feeder 3 import department's gas flow temperatures are 169.5 ℃.

Embodiment 3: setting material-gas ratio is 0.14.Close control valve 11, make its technology condition identical with DIET technology.Supplied materials pipe tobacco moisture content of drying base is similarly 26.6%, and containing the dry ice amount in the pipe tobacco of dipping back is 25%.All the other technology conditions are also identical with embodiment 1, and promptly carrying the A-A cross section air velocity of swelling pipeline 5 is 48M/S, and its initial airflow temperature is 340 ℃, and the superheated vapor volume is 8: 2 with the ratio of dry air volume in the air-flow.Carry on the swelling pipeline 5 near the gas flow temperature before the B-B cross section this moment is 252 ℃, and feeder 3 import department's gas flow temperatures are 236.9 ℃.The ruuning situation of its result and DIET process equipment is coincide.

Table one is the situation of carrying the expanded gas flow temperature to change along pipeline under the different material-gas ratio conditions with Fig. 2.As can be seen from Figure 2, different material-gas ratios makes and carries the reduction of expanded gas flow temperature that different slopes is arranged.And after the pipe tobacco moisture content reduced to a certain scope, the reduction of gas flow temperature was slower.But with water capacity be the circulation low-temperature airflow that do not heat of definite value with carry expanded gas flow to mix after, the descending slope of gas flow temperature is increase to some extent again.

The different material-gas ratios of table one are to carrying the expanded gas flow Temperature Influence

Sequence number	Material-gas ratio	Gas flow temperature in the conveying swelling pipeline (℃)			Back pipe tobacco moisture content of drying base (%) expands	Remarks
		Gas flow temperature in the conveying swelling pipeline (℃)					The A-A cross section	Before the B-B cross section	Feeder import department
		1 2 3	0.3 0.28 0.25	340 340 340			The A-A cross section	Before the B-B cross section	Feeder import department	172.6 180.9 194.3	145.5 154.4 169.5	8％ 8％ 7.5％	At the B-B section low temperature circulating current is mixed with delivery air
4	0.14	1 2 3	0.3 0.28 0.25	340 340 340	340	252	236.9	2.5％	There is not the low temperature circulating current to mix at the B-B section with carrying expanded gas flow	172.6 180.9 194.3	145.5 154.4 169.5	8％ 8％ 7.5％

Fig. 3 carries on the swelling pipeline 5 near the gas flow temperature before the B-B cross section and the relation of material-gas ratio.Be that gas flow temperature value and material-gas ratio are negative correlation.Along with the increase of material-gas ratio, carry the interior gas flow temperature of swelling pipeline obviously to reduce.

Pipe tobacco is carried in the expansion process, and initial gas flow temperature is higher, is the necessary condition of tobacco expanding.And the pipe tobacco moisture content of drying base falls after 9%, carry the expanded gas flow temperature to reduce to 160 ℃, even reduce to 140 ℃, and dried-up flavor occurs in the loss of broken, fragrance matter and the flue gas guarantee is provided for preventing that expanded cut tobacco from making in a large number, be the important method of improving the expanded cut tobacco quality.It should be noted that after improving material-gas ratio, the pipe tobacco of handling should evenly distribute in carrying swelling pipeline, inhomogeneous with pipe tobacco moisture content and filling value after preventing to expand.

Claims

1, a kind of method of expanded cut tobacco, be after pipe tobacco floods through inflating medium, it is that drying medium, its superheated vapor volume are 7: 3～9: 1 with the ratio of dry air volume that flow enters equably with the superheated vapor, initial temperature is that 320～380 ℃ air-flow is carried the also drying that expands in the expansion system, it is characterized in that: will carry the expansion system material-gas ratio by being increased to 0.2～0.35 less than 0.17; And the pipe tobacco moisture content of drying base has been reduced to 15%～16.5% ad-hoc location in carrying swelling pipeline, sending into water capacity reaches the lower circulating current of setting value, temperature and mixes with carrying expanded gas flow, make and carry the expanded gas flow temperature to reduce to 160 ℃ at discharge pit, minimumly reduce to 140 ℃, excessive temperature raises after can preventing tobacco expanding, and avoids the pipe tobacco moisture content excessively to be reduced to 2%～3%.

2, expanded cut tobacco method according to claim 1, it is characterized in that: improve the material-gas ratio of carrying swelling pipeline, under the condition constant at initial airflow temperature, that the air-flow transporting velocity is identical, can make and carry the expanded gas flow temperature to reduce quickly along pipeline, best material-gas ratio is 0.25～0.3.

3, expanded cut tobacco method according to claim 1, it is characterized in that: in the circulating current of carrying expansion system, send into temperature and be 100～105 ℃ steam, or spray into water smoke when sending into the steam of normal use in right amount, and control its flow, can make the circulating current water capacity reach definite value, reduce the circulating current temperature.

4, expanded cut tobacco method according to claim 1 is characterized in that, carrying pipe tobacco after expansion system expands, its moisture content of drying base through air-flow is in 6%～9% the scope of being controlled at, and preferably is controlled at 8%～9%.

5, adopt the equipment of claim 1～4 expanded cut tobacco method, be that air-flow is carried expansion system: comprise quantitative feeding equipment, charging gas lock (6), carry swelling pipeline (5), feeder (3), blower fan (2), discharging gas lock (1), deduster (19), air exhauster (20), steam supply pipe (16), combustion furnace (14) and connecting pipe and control valve etc. are formed, it is characterized in that, identical in capacity of equipment, under the constant condition of conveying air velocity, carry the expansion system material-gas ratio to increase, carry the area of section of swelling pipeline (being expanding tower) to reduce, corresponding heat consumes and reduces, and at circulating current pipeline (18) to the B-B cross section of carrying swelling pipeline (5), be provided with a bypass pipe (10) and control valve (11), so that water capacity is reached setting value, the circulating current that temperature is lower is delivered to the B-B cross section and is mixed with carrying expanded gas flow.

6, expanded cut tobacco equipment according to claim 5, it is characterized in that: in the capacity of equipment scope, suitably the control valve (15) in the control system, (12) reach (11), material-gas ratio that can control system and deliver to the circulating air flow in B-B cross section through bypass pipe (10), suitably regulate temperature with that a part of circulating current of carrying expanded gas flow to mix, can make the gas flow temperature of feeder porch reduce to 160～140 ℃, the expanded cut tobacco moisture content of drying base reaches 8%～9%.