US1025356A - Process of converting wood into paper-making stock and by-products. - Google Patents

Description

B. F. WILLIAMSON, w PROCESS OF GONVEETING WOOD INTO PAPER MAKING STOCK AND BY-PRODUGTS.

APPLICATION FILED NOV. 2'7, 1908. BENEWEDDOT. 11, 1911.

Patented May 7, 191.2.

aq wowtoz wi iweooeo To all whom it may concern:

UNITED STATES PATENT. onmon,

BAILEY F. WILLIAMSDN, OF GAINES'VILLE, FLORIDA.

Be it known that I, BAILEY F. VViLLIAM- son, a citizenof the United States, residing at Gainesville, in the county of Alachua and State of Florida, have invented certain new and useful Improvements in Processes of Convertim Wood into Paper-Making Stock and By-lroducts, of which the following is a specification.

This invention relates to an improved process of converting wood in'eo paper-making stock and by-products, and refers more particularly to a process especially suitable for treating resinous woods, such for ex ample as Southern such that the ultimate fiber of the wood is isolated from the intercellular matters and converted into paper-making stock, and at the same time the oils of the wood released, removed, and recovered.

are to provide a process whereby resinous woods may be successfully treated and a maximum quantity of the ultimate fiber in its purest form secured; to provide a process whereby the elimination of the resin and oils from the wood results inthe release of'the contained 0118 and resin and in the formation pentine being volatilized and carried off as fast as released to provide aprocess whereby the chemical treatment to which the wood is subjected results in producing a softened and improved quality of fibe'r5'to provide a process in which the chemical reactionsare ly,- efiiciently, and

'oils by] releasing them entirely from the resinous matter;

to provide a process which may be carried out progressively and as a continuous operation, practically in a single digester or suitable receptacle; toprovide a process which effects the rapid and thorough reduetioniof thematerial with the use of a minimum tions result in eliminating alarge percentage of the coloring-matters and thus reduces the amount of bleaching necessary, n case Specification of Letters Patent. Application filed November 27, 1908, Serial No. 464,641.

ines' the rocess bein P a:

of aresin soap in s0lution,-the oils and tur- ,haust 1ng mechanism,

yield of superior fiber;

quantity of chemical; to provide a process in which the chemical reac-' Patented May time, Renewed october 11, 1911. Serial No, %,161.

to provide a process in which the reduction" treatment is accomplished practically througl'iout in the absence of air, thereby avoiding the formation of oxy cellulose and at the same time accelerating the process; and in general, to provide an economical commercially practicable process of the character referred to.

The invention consists in the matters hereinafter described and more particularly pointed out in the appended claims.

The process may be more readily understood by a description of a preferred manner of carrying out the same in connection with suitable apparatus, in the accompanying drawing.

In said drawing the single figure illustrates in side elevation a digester, a condenser, a receptacle for the condensed prod- Among the salient ob ects of the invention nets and suitable connections, etc.-

In carrying out the process, n reducing long leafed such as that illusrtated' pine, for example, and using apparatus substantially like that herein" i illustrated, I proceed as follows: I first chip the wood by the use of an ordinary chipper, into com aratively small fragments, out transverse y or obliquely of the tgrein of the wood, so that the 1 grain and pores. are severed at frequent intervals, and charge a suitable quantity of these chips into the digester 1. I then hermetically closet-he digester and by the aid of a suitableexconnected with the digester through the exhaust pipe 2, exhaust the air from the digester comercially practicable-say, about twenty produced. the required vacuum, and while maintaining the same, I introduce the cooking liquor through the inlet pipe 3; this as thoroughly as is five inches or upward of vacuum. Having cooking liquor being a solution of caustic soda of grees to thirteen 'suflicient quantity to cover the charge. The introduction of the cooking liquor while the charge is under vacuum, results in the rapid filling or impregnation of the pores of the wood-with the liquor. I now admit steam through the sn 7 ply pipe i, wh-ichenters the bottom of-the igester, preferably at a pressure of about 120 pounds. The admission ofthe steam ischntinueduntil the'gage iii-- dica'tes a plenum pressure in the -digester, whereupon I open to a slight extent the a strength ranging from five de-- degrees Ba um, and of 1 cock or valve 5 which controls the steam outlet pipe 0 leading from the top of the digesterto,.and connecting with, a closed condensi'g coil S in -the condenser 7.

As soon as the caustic liquor is intro duced, it begins to attack and dissolve the resins contained in the wood and this reaction is accelerated by the heat resulting from the admission of the steam. The combination of the alkaliwith the resin forms resin soap, and in so doing releases the contained turpentine and heavier oils; these being volatilized by the steam and carried oil continuously and as released, to the-condenser. The valve or cook 5 will of course be adjusted to properly regulate the escape ofsteam and volatilized oils.

The cooking operation is continued by the continuous admission of steam at about the pressure stated, the pressure in the di-.

gester gradually rising as the temperature therein approaches more and more nearly the temperature of the steam at admission. The choking thus continued until the inter-cellular matter is practically all dissolved and the ultimate .tiber set free, which I have found in practice will occur in fromsix to ten hours under the conditions described.

The principal quantityof turpentine and of the other oils will be expelled and carried over with the steam during the earlier stages of the process, but some oils will continue to come over until, well into the latter stages of the process. The circulation of the steam throughthe tligester is, however, continued throughout "the entire cooking process. Ali-the conclusion of the cooking,

, the charge isblown off through the blowotl' pipe 8 into a suitable pit or other receptacle, in the usual manner. Subsequently the dissolved intercellular matter or lignin is washed out andv separated from the ultimate fiber in any suitable or usual manner. It is to be noted that the resin soap will be in solution with the intcrcellular' matter and in case the soda is reclaimed, the resinous material will-supply a. large proportion of the fuel nccessarytotelfect its recovery.

' The turpentine and other oils, together with the steam,are condensed in the con denser and flow downwardly into the receptacle 9, where -a separation of the water from the oils is effected by gravity. The water flows off through the pipe 10, the intake end of which is located near the bottom of thereceptacle 9, in a. usual and well understood manner. it is to be noted that as soon as the caustic liquor enters the pores of the wood and the chips begin to swell, the contained gum is expelled, and this expelling action is of course facilitated and augmented by the heat supplied from the steam. It follows that. the formation of the resin soap proceeds rapidly and that the turpentine and heavier oils are set free at a corresponding rate. It is further to be noted that the soap so formed performs the double function of acting as a solvent of the intercellular matter or lignin and at the same time protects the ultimate fiber from the harsh action of the caustic liquor and undoubtedly has a softening effect upon the fiber; Still further, itis to be noted that the elimination of the air before the cooking liquor is admitted. prevents the forma tion of oxy-cellulose, which would otherwise occur to a damaging degree in the presenceof air and the alkali. Moreover, the continuous circulati'onofthe steam through the digestcr serves to expel and carry oft any small quantities of air which may be set free from the pores of the wood during .the disintegration of the latter.

I have discovered that. the more or less .rapid deterioration of paper after it has been made is to :1V substantial extent at least due to the presence of oxy-cellulose wlnch is formed to a greater or less degree in the course of the preparation of the fiber, under all usual methods of making chemical fiber. By preventing its formation, as hereinl'iefore described, the permanency or keeping qualitiesof the paperaififfea ehhanced. Another and important result of preventing the formation of the oxy-ccllulose is that the subsequent bleaching of the stock is accomplished with a very substantial smaller quantityof bleaching chemical;

The fiber produced by the process above described is characterized by unusual softness, strength andlightness of color before bleaching. The amount of caustic soda cmployed in effecting the reduction. it will be noted is comparatively small, (from 9 to 15 Baum) and the yield of ultimate fiber is very large because of the mild treatment to which the material is subjected. T he yield of turpentine and other oils is likewise very high. since these constituents are entirely set free and the amount recovered approaches quite closely to the total contained in the wood.

While 1 have herein described what I believe to be a preferred way of carrying out the process, yet it will be understood that the process may be modified without departing from the spirit thereof and without departing from the invention.

I claim as my invention:

1.. T he improvement in the art of making pulp. which consists in placing the comminutcd stock in a closed chamber and substaintially depriving it of free oxygen, then, while maintaining the exclusion of free oxygen. subjecting the material 'to the action of caustic alkali solution and heat and cooking the material. and as the cooking proceeds withdrawing the volatilized products as formed and the free oxygen as released, and

' fiber set free.

. therefrom to a relatively high v'acuum, then,

while. substantially maintaining the exclusion oi air, admitting a caustic alkali solu' tion of relatively mild strength and cooking withdrawingvolatilized products as form and oxygen as set free, so as to accomplish the reduction without oxidation, and continuing the cooking under these conditions until the desired reduction is completed.

'3. The improvement in the art of making pulp from resinous wood, which consists in placing the comminuted wood in a hermetically closed chamber and exhausting the air to a relatively high vacuum, then, while suhstantially maintaining the exclusion of air, admitting a causticalkali solution of relatively mild strength and cooking under pressure by the circulation therethrough of steam substantially free from oxygen with: drawing the volatilized products as :iormed and. oxygen as set free, so as to accomplish the reduction without oxidation of the celluiose, and continuing the cooking under these conditions until the desired reduction is completed. i

4:. The improvement in the art ofmaking pulp from resinous wood, which consists in placing the comminuted wood in a closed chamber and substantiallyexhausting the air therefrom, then, while excluding free oxygen, cooking in a caustic soda solution,

of a strength less than 15 Baum, by circus lu'ting steam therethrough which is practieally devoid of free oxygen, Withdrawing the voiatuized products as formed and oxygen as set free, so as to aocom lish there- 'duction without substantial oxi ation of the cellulose, continuingthe operation until the reduction is 00121 eted and then separating the-cellulose fiber 5. The improvci'nent in the art of matting from the residue byiwash pulp from resinous Wood, which consists in placing the ooniminuted wood in a closed digester and suhstantially exhausting'the air therefroxmthen, while excluding free oxygen, cooking in a caustic soda solution. of

such predetermined strength that "it will,

when combined with the'resins and heavier oleaginous materials of the wood, form a soapy solution mildly. alkaline, withdrawing the volatilized products as formed and oxygen as set free, so as to accomplish the re cluction without substantial oxidation of the cellulose, continuing the cooking in the pres- ,ence, and under the dissolving action, of i said soapy solution until the reduction completed and finally recovering the ulti mate fiber from the residue.

6. The improvement in the artef making Wood pulp, whichconsists in efiectin an initial stage of. the reduction and removiug the free oxygen thereafter as liberated during the progress ofthe reduction, whereby the reduction is performed under condithe reduction by cooking the wood in allra 11 setions substantially free from the eontaminatingeifects of free oxygen.

v BAILEYF. WILILIA "il itnesses: i HOWARD A. CooMns, E. G.' Mcflas' si

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