US1538265A - Process for recovering nicotine from tobacco - Google Patents

Description

h; B. ARNOLD PROCESS FOR RECOVERING NICOTINE FROM TOBACCO i J N Y L] T J l h F i; 42

i g l W WvW nicotine is first released alkali to the tobacco, the. function of which Patented May 19, 1925.

UNITED STATES I 1,538,265 PATENT OFFICE.

ROBERT B. ARNOLD, 0! 8T. LOUIS QIISSOUBI, ASSIGNOR TO HALL TOBACCO CHEMICAL COMPANY, OF NEW YORK, N. Y., A CORPORATION OF NEW JERSEY.

PROCESS FOR BECOVERIIQG NICOTINE FROM TOBACCO.

Appllcationfled February 21, Serial No. 535,250.

To (1U whom it may conaem-:

Be it known that I, ROBERT B. ARNOLD, a citizen of the United States, and resident of St. Louis, in the county of St'. Louis and State of Missouri, have invented certain new and useful Improvements in Processes for Recovering Nicotine from Tobacco, of which the following is a specification.

My invention relates generally to the recovery of nicotine from tobacco, and is especially directed to an improved process for extracting nicotine from waste tobacco, leaving a residue suitable for use as fertilizer.

My process is of the type in which the is to combine withthe acid substances holdmg the nicotine; and the latter is then extracted in vapor form whichcarries off a certain amount of nicotine vapor at temperatures well below the boiling point of nicotine. More specifically, my invention pertains to a process of this kind in which water is applied directly to the tobacco, and is then turned to vapor by suitable heating means. I

.My improved process is in general designed to increase the cfliciency and decrease the cost of this type of process. To this end, one important object is to decrease substantially the amount of heating necessary while obtaining a satisfactory yield of nicotine, as the cost of heating is a rincipal item of expenditure in this type of process. I have accomplished this principally in two Ways; first, .by reducing the moisture to be evaporated toa minimum; and secondsby evaporating the moisture under conditions most favorable to its carrying its maximum load of nicotine.

One important object in connection with the reduction of the quantity of moisture to be evaporated is toevaporate the moisture in such circumstances and under such conditions as to increase the carrying capacity for nicotine vapor, as compared with the carrying capacity of steam under the conditions existing in the practice of former processes. More specifically, it has heretofore been considered desirable to evaporate in a partial vacuum, following well-established distilling and evaporating practice, the advantages of. usinga vacuum in the latter art being well-established. However,

I have ascertained that while the carrying power of vapor for nicotine is relatively.

y pp y n a small under the vacuum generally employed heretofore, this power increases markedly as the pressure increases to and above atmospheric pressure. I have also ascertained "that the advantages attendant upon this increased nicotine carrying power more than offset any possible disadvantages incident upon departure from distillation in a vacuum. An important feature of my invention is, therefore, the employment in an extraction process of the particular type above indicated, of steam at approximately atmospheric pressure for extracting the nicotine.

Another important object is the evolution of a process in which all the moisture evaporated carries substantially its full load of nicotine. Processes heretofore in general use have employed a substantial quantity of steam in excess of the steam or vapor from the evaporation of the tobacco moisture content with the result that, While the steam first passing may carry its full load of nico-- tine, the last of the steam will carry only a small percentage, or none at all. I have ascertained that the carrying capacity of' steam for nicotine vapor at standard"titer mospheric pressure is approximately 4%; and I employ an amount ofwater, Including that already present in the tobacco material, only slightly in excess of the total necessary to carry off all of the nicotine present in the particular tobacco being treated, the quantity of the nicotine varying with difierent types of tobacco, and being readily ascertained by well-known methods. In accomplishing this object, I have found that the amount of water necessary is so small that the tobacco material does not even remotely approach saturation; and such material, after being treaied with water according to my process. has the physlcal a pearance of bein dry or at most on y slightly moist. is physical condit on of the tobacco is of great advantage in the ratus employed, and also possesses ot physical and chemical advantages not necessary to enumerate.

In order to release the nicotine from the acid combinations which hold it in tobacco, it has been the general practice to employ an alkaline substance in sufficient quantity to neutralize all the acid elements of the tobacco. One principal alkali which has been employed is generally known as soda,

particularly in the form known as caustic soda. I have found, however, that the use of soda institutes a large number of secondary chemical reactions in the tobacco, which generate a more or less gelatinous product. This tends to enclose at least part of the nicotine, preventing it from belng carried ofi by the steamfand the ercentage of nicotine removed is thereby dlminished. I have ascertained that lime is substantiall superior to soda for this purpose, either 1n the 1form of milk of lime or of dry hydrated A further feature of my invention has as its object an improvement in the uniformity and efliciency of action of the alkali employed; though this feature is not necessarily dependent upon the employment in the process of the features above set forth. I have determined that the alkali is most effective when mixed with the tobacco material in dry powdered form, the water being added after such intermixture. By this arrangement a much more uniform and effective neutralizationof the acids in the tobacco is obtained than where a fluid alkali, such as a soda solution, is applied to the tobacco material as heretofore roposed. This effect is particularly marked when dry hydrated lime is used. I will now set forth the details of the preferred form of my process, together with one type of standard commercial apparatus the tobacco. and thereafter mixture, ,while heretofore it has been the which may be used in the process. This apparatus is illustrated in the drawings. which show a somewhat diagrammatic long tudinal vertical section through a machine of the rotary drum drier type, together with suitable inlet and outlet connections. The tobacco material should be in finely divided form to permit rapid and thorough pricessing; and should, if necessary, be ground, preferably to a screen having a fi inch mesh. It is then treated with alkali in such a Way that the acids are just neutralized, rendering the material veryslightly alkaline. I have materially improved this step of the process by mixing a dry finely divided alkali with mois tening the practice to add the alkali in liquid or solution form. I I have found,that by mixing the alkali in a dry state with the tobacco, I not onl mixing, lint also a higher neutralizing eiiiciency. More accurate measuring of proportions is also attained. However, this preferred method of alkaline treatment is not essential to other features of my invention hereinafter set forth.

I therefore prefer to neutralize the acid by adding to the .finely divided material a suitable quantity of dry powdered alkali, preferably hydrated lime, and thoroughly point where it will pass a the action takes secure a more thorough and rapid.

messes I mix the massin any desired way. The amount of alkali used depends upon. the

kind oftobacco material processed, the twoimportant factors being the amount of acid 111 the tobacco and its hardness or lmpermca bility, the latter however being of much less importance than the former.

thoroughly mixed, the proper amount of Water is added. If desired, the water added may be heated, or may be in the form of steam, reducing the amount of heat necessary to vaporize the water later in the process. these features being controlled largely in commercial considerations, including the type of heating plant employed. In calculating this amount, the quantity of water already present in thetobacco should. be included.

As heretofore indicated, sufficient Water is such that when evaporated it will he just capable of carrying off all of the nicotine present in the tobacco. The amount used depends upon the acidity and denseness of the tobacco and the amount of nicotine present. A slight exces f water is also required, as a little water remains in the tobacco after processing under ordinary commercial conditions, and allowance should also be made for ciency. I have found that the most effective extraction is accomplished by employing from 30 to 40% by Weight of water, although effective results are obtained with anywhere from 25 to 50% of water. It is understood that these figures are largely illustrative, as the percentage of available nicotine in the tobacco is the determiningfactor.

Upon the addition of the water the alkali becomes effective to neutralize the acids, and it has been found desirable with the denser types of tobacco to allow the mixture to stand for a certain period to insure complete alkaline action. With porous tobaccos place almost immediately. With the denser tdbaccos a period of about two hours is generally sufiicient. Furthermore, the more acid tobaccosrequire slightly more water to expedite the neutralizing action.

I wish-to emphasize the fact that when the proportion of Water indicated herein is employed, it isabsorbed so, thoroughly by the tobacco that the latter retains its substantially dry appearance, being at most only slightly moist, and it may be handled as a dry substance. It maybe noted that ordinary tobacco is capable of taking up apfailure to attain full efiifore reaching complete saturation; .so the difference between the amount of water used in processes employingsaturated tobacco and that set forth herein will be evident. Such prior processes, because of the much larger quantity of water employed, involved difiiculties and disadvantages in the handling of the material, as well as greatly inferior eflicienc of recovery.

The treated material 1s now subjected to heat suflicient to turn the water to vapor which carries off the nicotine. This step is carried out in any preferred form of apparatus, preferably of the drier type, where heat may be efliciently applied and the vapors collected and condensed to recover the nicotine. small amount of water, the quantity of heat re uired is correspondingly small, the vapor belng loaded to full capacity with nicotine.

, One of themost important features of my process is the elimination of vaporizationn a yacuurn, heretofore thought necessary 1n this particular type-of nicotine extraction 7 process. I have found that the carrying ca pacity of steam for nicotine vapor increases with pressure; and while steam at standard Y atmospheric pressure and 212 F. will carry approximately 4% of vapor, it will carry only about of one per cent of the vapor 1n a 25-1nchvacuum. I therefore carry on the vaporization of the water at approxi-.'

mately atmospheric pressure, preferably. in a drum type drier or still. This feature also has numerous practical'a-dvantage's, such as the elimination of the vacuum pump and special construction necessary for vacuum systems. Indeed, it may be practicable to carry on this process under pressures higher thanth at of the atmosphere; butl prefer the latter, owing to the increased ease with which it maybe carried out under commercial conditions as compared with either a vacuum or a pressure system.

Substantially all of the water employed is vaporized, though under ordinary commercial conditions the highest efiiciency is obtained by leaving something less than 5% of moisture in the tobacco. This process may be carried out in various ways. I have shownin the drawing somewhat diagrammatically one apparatus suitable .for my purposes, including a drier of the drum type having a horizontal cylindrical body or!- drum 10 provided with inletsll having the usual covers, not shown, and outlets 12 at the bottom; The material in the drum is agitated by paddles 13 mounted on a central 5 sired way, as by-heating fluid in jacket 15,.

shaft 14. The drum 10 is heated in any de- Owing to the relatively requiredthe temperature of the tobacco in a typical process of this type running from 212 at thestart to about 250 at the close-the heating operation for vaporizing the water is much simpler and more eco-- nomical than 1n former processes.

For instance, while steam may be employed, either 1 in the drier shown or in others of a similar type, suitably heated oil may be circulated rough the jacket and paddle shaft, this method being found eflicient and economical at the temperatures mentioned.

The tobacco material may be introduced into the drum in various ways. I have shown an arrangement in which the various materials used are stored above the drier, as on the second floor of' a building. They are introduced through chutes 17 registering with the drum inlets 11; and the material may either be shoveled into these chutes, or if desired introduced automatically. Where the alkali and tobacco are to be mixed in dry form inthe drum itself, the tobacco may be run from bins into chutes 17 through pipes 18, the lime entering through pipes 19. The drier may be supported by pillars 20 at a distance above the floor sufficient to allow the discharge of the processed material through discharge openings 12 into carriers introduced beneath the drum. In the drawing 21 designates diagrammatically the first floor ofthe building, and 22 the second floor.-

The Water is contained in tanks 23, and is introduced intothe drier through pipes 24, the flow being controlled by cocks 25, so that the amount of water used may be accurately controlled. Forinsuring rapid and even moistening of the material, steam or air injectors26 may be used for introducing the water; and injectors of this type may be employed at. or adjacent the drum openings 11. The latter injectors are wellv positioned to moisten the center portion of the mix; but when it is desired to wet-the material as it is inserted in the drum without preliminary agitation in the drier itself. these injectors are properly located for the purpose.

With this apparatus, if desired, the dry lime and tobacco material may be first inserted and thoroughly mixed by the paddles 13. The water may then be i'njected,.a-nd

the heat is turned on, and the-steam generated will carry off the nicotine through pipes-27, from which they pass to any standard tyne of condenser.

While I have shown a single drum 1n which the entire process may be carried out.

with obvious advantages; and while I have indicated that the tobacco and alkali may receive the water, or if desired, the water -'may be applied with the lime and tobacco as they are fed into the drum; it may be found desirable to varythis practice somewhat. For instance, it is highly desirable to maintain the drier in constant Operation, and

Where the preliminary mixing and ordering steps require time, they may be carried out separately, either in small mixers adapted for that purpose, or by manual labor, suit able bins bein provided in which the tobacco material is allowed to stand after moisture has been applied until a sufiicient amount is prepared and is ready for insertion in the drier. However, it is highly de-- sirable to employ an enclosed container during the neutralizing process, as ammonia fumes are given ofi which are very objectionable. It will be noted that when the neutralizing reaction is taking'place either in the main drum drier or in separate closed mixers, since the fumes are carried on by suitable outlet pipes, no expensive ventilat ing system for the workroom is required as heretofore.

Where the, tobacco carries a high percentage of nicotine it is desirable, In some instances to subject the tobacco to a succession of moistenings, and in order to conserve heat I prefer to remoisten the tobacco by injecting steam into the bottom of the drum as the tobacco dries out. This steam diffuses through the mass of the tobacco, absorbs a certain amount of nicotine, and passes of? to the condenser with the moisture evaporated by the heat of the drum. The result obtained by thus injecting steam into the drum is similar to what would be Ob-e' tained if a larger amount of water had been added to the tobacco, but the time consumed in the extraction of the nicotine is ver much less. Steam may be introduced through pipes, such as the injector pipe shown at 26, connected at the bottom of the drum.

The tobacco should be kept slightlv moist until the extraction of the nicotine is completed, since otherwise fine dust may, as the tobacco dries, be carried over to the condenser. For this purpose a measured amount of water can be admitted to the drum at certain intervals or a small stream of water can be permitted to fiow into the drum continuously. The amount of water should be regulated so that the tobacco is kept slightly moist. When the extraction of the nicotine is completed, the water is cut off and the tobacco is completely dried.

While I have indicated the preferred form of my improved process, together with sev-.

- eral lines of variation therein, it will be apparent that numerous other changes and deviations can be made by those skilled in the artwithout departing from the invention as set forth in the following claims. Moreover, it will be evident that certain portions ofmy process, such asthe heating at atmospheric pressure and the mixing of the lime in dry condition, may be incorporated in other standard processes; and my invention comprises such use of these features, as indicated in the claims.

I claim:

1. The processof recovering nicotine from tobacco material, which consists in mixing the material with'an alkali, adding moisture to the mixture suflicient to hold the nicotine content in solution during the evaporation thereof, but insufiicient to be perceptible, heating the mixture to evaporate the moisture, and condensing the vapor.

2. The process of recovering nicotine from tobacco material, which consists in mixing the material with an alkali in the dry state, adding moisture to the mixture sufiicient to hold the nicotine content in solution during the evaporation thereof, but insuflicient to be perceptible, heating the mixture to evaporate the moisture, and condensing the vapor.

3. The process of recovering nicotine from tobacco material which consists in mixing the material with an alkaliand with an amount of water suficient to hold the nicotine content of the material in solution, but insufiicient to be perceptible the weight of the total water content bein not more than 50% of the Weight of the ing ofi the extracted nicotine, the mixture being at substantially atmospheric pressure when heated,

5. The process of recoverng nicotine from tobacco material which consists in mixing thematerial with-a dry alkali and with an amount of water substantially equal only to that necessary for generating the minimum quantity of steam capable of extracting and ry tobacco material, and in heating the mixture to vaporice carrying ofi all the nicotine present in the tobacco material and in heating the mixture to transform the water into steam for carrying off the extracted nicotine. 6. The process of recovering nicotine from tobacco material which consists in mixing the material with an alkali, in applying to the mixture while in a closed container an amount of water suficient to hold the nico-.

tine content of the material insolution, but

insufiicient to be perceptible in agitating the adr from finely divided tobacco material, steps which consist in mixin dry hydrated lime with the tobacco material, and then adding moisture to the material so mixed.

perceptible ,tureto evol 9.' The process of recov'erin nicotine from tobacco material which inclu es mixing with the material in finely divided form a dry alkali, applying thereafter to the material an amount of water sufiicient to raise the water content of the tobacco to a point onl slightly in excess of the minimum capab e of carrying off the nicotine, and substantially less than the amount required to be and applying heat to the mixve nicotine-carrying vapors.

. 10. The process of recovering. nicotine from tobacco material which includes mixing with the material in finely divided form a dry alkali, applying thereafter to the ma terial an amount of Water sufficient to raise the water content of the tobacco to a point only slightly in excessof the minimum capable of carrying 0d the nicotine, and substantially less than the amount required to be perceptible; and applying heat to the mixture to evolve nicot ne-carrying vapors,

the mixture being at not substantially less than atmospheric is applied thereto.

11. The process of recovering nicotine pressure when the. heat from tobacco material, which consists in adding to the tobacco material a quantity of'moisture less than the absorptlve capacity thereof, heating to evaporate the moisture, and condensing the vapor.

Signed at Durham in the county ofw Durham and State of N orthiCarolina this 13th day of February A. D. 1922.

ROBERT B. ARNOLD.

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