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Publication numberUS2805156 A
Publication typeGrant
Publication dateSep 3, 1957
Filing dateJan 21, 1953
Priority dateJan 21, 1953
Publication numberUS 2805156 A, US 2805156A, US-A-2805156, US2805156 A, US2805156A
InventorsHenry I Mahon, John H Payne, Kenda William
Original AssigneeHawaiian Dev Company Ltd
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Process for the separation of pith and fiber components of bagasse
US 2805156 A
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Description  (OCR text may contain errors)

Sept. 3, 1957 J. H. PAYNE l-:TAL 2,805,156

PROCESS FOR THE SEPARATION OF PITH AND FIBER COMPONENTS OF BAGASSE Flled Jan 21, 1953 2 Sheets-Sheet l amsn/Ne V61@ 77694 SKU/NG .14E/V496J MAZ/JON INVENTORS Sept.y 3, 1957 Filed Jan. 21, 1953 J. H. PAYNE ET A. PROCESS FOR THE SEPARATION OF PITH AND FIBER COMPONENTS BAGASSE- 2 Sheets-Sheet 2.

He. Z.

. #Trae/vias PROCESS FR THE SEPARATEN GF PIT H AND FBER COMPNENTS F BAG-ASSE John H. Payne, William Kenda, and Henry l. Mahon, Honolulu, Territory of Hawaii, assignors, by mesne assignments, to Hawaiian Development Qompany, ist-rl., Honolulu, Territory of Hawaii, a corporation of the Territory of Hawaii Application `annary 21, 1953, Serial No. 332,276

4 Claims. (Cl. 92-14) To accomplish this, it is desirable to remove from theV bagasse a major portion of the undesirable pithy component and to eliminate the large quantity of occluded dirt and insoluble matter which always accompanies bagasse, due to the conditions under which the sugar cane is harvested. One of the principal objects of this invention is,

then, to provide a process for the separation from bagasse of clean fiber suitable for paper pulp production.

Another object of this invention is to provide a process for the separation of pith and fiber components of bagasse, in which process a minimum amount of tine bagasse liber is produced, and which process provides substantially complete removal of objectionable ash impurities from the bagasse fiber.

Still another object of this invention is to provide an eiiicient and relatively inexpensive process for the separation from bagasse of a liber suitable for the production of paper pulp and dissolving pulp.

Other objects and advantages of this invention, it is believed, will be readily apparent from the following detailed description of a preferred embodiment thereof when read in connection with the accompanying drawings.

In the drawings:

Figure 1 is a flow sheet illustrating a process which comprises a preferred embodiment of this invention.

Figure 2 is a diagrammatic vertical section of a swing hammer disintegrator utilized in carrying out the preferred process of this invention.

Figure 3 is a sectional view, taken substantially on the line 3 3 of Figure 2.

Referring now to the drawings, and particularly to Figure l, it will be seen that bagasse, which is in the moist condition in which it is usually delivered from the sugar mill, is charged into a cooker which may comprise a conventional pulp mill digester, pulper or vegetable blancher. mixture is heated by means of steam and maintained at the desired temperature for a given period of time. It has been found that the addition of from about 0.5 to

about 6 percent caustic soda, based on the dry weight of The bagasse is immersed in water, and thek Patented Sept. 3, 1957 the bagasse at the time of its introduction into the cooking equipment. In operation, we have found optimum results are obtained when the bagasse is cooked for about one hour at a temperature of from 190400"V F. with a caustic soda concentration of 3-6 percent, based on the dry weight of bagasse. Under some conditions, a cooking period of about thirty minutes is sufficiently long.-

The temperature should be maintained in excess of 150 F., but at, or near, such temperature, a longer cooking period is desirable. The consistency of the bagasse during cooking may be varied over a wide range preferably from about 2 to about 7.5 percent.

After cooking, the cooked bagasse stock is diluted with water in a washing and dilution tank, as shown in Figure 1. Preferably, suflicient water is added to bring the consistency down to about 2 percent or less. tent to which dilution is carried out depends upon the amount of dirt the original bagasse contains. Where excessive amounts of dirt are present, it is desirable to dilute the stock to a consistency of 1 percent or less, washing out the large dirt particles to the sewer through a screen (not shown) in the dilution tank prior to furi ther processing.

The cooked and diluted bagasse stock is then pumped to a vertical swing hammer disintegrator generally indicated 10, where the simultaneous disintegration of the bagasse i. e., loosening of the pith anddirt components from the fiber and separation of the fiber from the pith and dirt particles is carried out.

Referring in particular to Figures 2 and 3, the disintegrator 10 is providedl with a screw-type feeder conveyor 11, the outlet of which leads into the casing 12 of the disintegrator proper. A vertical shaft 14 is suitably journaled in the casing, yand is connected in driven relation with the drive shaft 16 of a motor 17 by means? of a coupling 18. The casing l2 is provided with an annular outwardly-extending shoulder 20, depending from which is a cylindrical housing 21, downwardly` through which extends the shaft 14. A plurality of swing hammers 25 are pivotally connected to flanges 26 secured to the shaft. Surrounding the swing hammers 25', and closely adjacent the `outer ends thereof, is a cylindrical screen 30.

Connected to the bottom of the housing 2l, and to the bottom of the screen 30, is a double-walled body por- I tion 32, and depending therefrom is a separating discharge device 33 which includes an outer frusto-conical section 34 communicating with the annular space 35 between the screen 30 and housing 21. Centrally of the section34, and communicating with the central chamber defined by the screen 30, is a product discharge section 36 which is connected to an outlet conduit 38.

Wash water is introduced into the conveyor 11 by means of the pair of spray heads'40. Additional wash water is applied to the operating section of the disintegrator by means of three spaced spray heads 41 which are directedupwardly as shown through the agency of the elbow fittings 43. The use of Wash water at these points improves the separation of the pith and liber and also facilitates the removal of dirt particles.

Preferably, the screen is provided with perforations of about 1/16 inch diameter, although perforations of 1/32 inch and '/32 inch have been used successfully. A shaft speed of 3,600 R. P. M. appears to produce the most desirable fiber product, although satisfactory results have been obtained at a speed of 1,800 R. P. M.

The cooked and diluted bagasse stock is pre-broken by The exwardly through the screen perforations by continued centrifugal force. These dirt and pith particulars are discharged downwardly through the section 34 and there discarded. The fiber is retained on the interior Vof the screen, and then falls downwardly through the discharge section 36, from Where it is conveyed through the conduit 38 to be stored for further processing in accordance with conventional paper mill practice.

By the use of the above-described process, a high recovery of clean, acceptable fiber is obtained. The cooking step produces sufficient softening of the libre bundles so that the action of the disintegrator does not reduce the fiber length to an undesirable extent, yet enables efficient separation of the undesirable pith and other foreign matter.

It will be readily apparent to those skilled in the art that ash and dirt particles are undesirable components of pulp for paper and viscose products. In the utilization of dissolving pulp for viscose production, the presence of substantial amounts of manganese, copper, and iron in the pulp has a deleterious effect on the Yviscosity of the resulting viscose. We have found that the process herein described removes a substantial portion of the soil ash which contains these offending impurities. The ash removal obtained with the present process is -much greater than that achieved by normal digestion and pulping methods heretofore recommended for bagasse pith and fiber separation.

Tables I and Il below provide specific examples of the efficacy of the process of this invention in removing ash impurities, as compared to other processes.

Table I Ash, FezOa, Cop- Man: Material (Dry Basis) perperper, ganese,

cent cent per percent cent 1. Mill bagasse 2.26 .216 .0010 .0029 2. Dry Screened ber 1. 72 250 V.0048 .0022 3. Pulped (3% NaOH, 190 F.) and wet screened ber 0. 86 .044 .0007 .0008 4. Our process 0.48 .030 .0003 .0003

Table Il Ash, FerOa, Cop- Man- Material (Dry Basis) perperper, ganese,

cent cent' perpercent cent 1. Pulped (6% NaOH, 200 F.) and wet screened iiber 2.13 328 .0060 .0028 2. Our process 0. 68 020 .0002 .0008

Material No. l in Table I was obtained from the discharge roll of the last mill in a cane sugar factory. Material No. 2 was obtained by passing mill bagasse containing 45 percent moisture over a l2-mesh Rotex screen. Material No. 3 was produced by pulping mill bagasse in a .standard pulp mill pulper for one hour in a solution containing 3 percent caustic soda based on the dry weight of the bagasse at 190 F., and then wet screening the pulped stock in a rotary screen to produce the fiber. Material No. 4 was produced by the process of this invention, the cooking stage being carried out in a pulper for one hour in 3 percent caustic soda at 190 F.

Materials Nos. l and 2 of Table II correspond to Nos. 3 and y4, respectively, of Table with the exception that, in both of the former cases, the cooking conditions were 200 F., the solution containing 6 percent caustic soda based on the dry weight of the bagasse.

The above description and examples are intended to be illustrative only. Any modification of or variation therefrom which conforms to the spirit of the invention is intended to be included within the scope of the claims.

We claim:

l. In a process for the treatment o f bagasse wherein the bagasse is cooked in an aqueous medium for a sufficient length of time to produce a material containing softened bagasse fibers, bagasse pith and foreign matter, the steps of continuously advancing said material while in a wet condition downwardly through a zone of disintegration surrounded by a substantially vertical screen while `directing sprays of water into said zone, subjecting the material in said zone simultaneously to impact disintegration, centrifugal attrition and continuous washing action so that the pith and foreign matter are loosened from the fibers without substantial disintegration of such fibers and are forced outwardly through Vthe perforations of said vertical screen, the fibers being retained within said zone by said screen and passing generally Vdownwardly through said zone, discharging the pith and foreign matter passing outwardly through said screen, and separately discharging the downwardly moving fiber relatively free of pith and foreign matter vfrom the lower end of said zone.

2. In a process for the treatment of bagasse wherein the bagasse is cooked in an aqueous medium for a sufficient length of time to produce a material containing softened bagasse fibers, bagasse pith and foreign matter, the steps of continuously advancing said material while in a wet condition downwardly through a Zone of disintegration surrounded by a vertical screen against upwardly directed sprays of water, subjecting the material in said zone simultaneously to impact disintegration, centrifugal attrition and continuous washing action so that the pith and foreign matter are loosened from the fibers without substantial disintegration of such fibers and are forced outwardly through the pcrforations of said vertical screen, the fibers being retained within said zone by said screen and passing generally downwardly, discharging,- the pith and foreign matter passing outwardly through said screen, and separately discharging the downwardly moving fiber relatively free of pith and foreign matter from the lower end of said zone.

3. In a process for the treatment of bagasse wherein the bagasse is cooked in an aqueous medium for a sufficient length of time to produce a material containing softened bagasse fibers, bagasse pith and foreign matter, the steps of diluting said material with water to a consistency of less than 2 percent, continuously advancing said material while in a wet condition downwardly through a zone of disintegration surrounded by a vertical screen against upwardly directed sprays of water, subjecting the material in said zone simultaneously to impact disintegration, centrifugal attrition and continuous washing action so that the'pith and foreign matter are loosened from the fibers without substantial disintegration of such bers and are forced outwardly through the perforations of said vertical screen, the fibers being retained within said zone by said screen and passing generally downwardly, discharging the pith and foreign matter passing outwardly through said screen, and separately discharging the downwardly moving fiber relatively free 0f pith and foreign matter from the lower end of said zone.

4. In a process for the treatment of bagasse wherein the bagasse is cooked in an aqueous medium for a sufficient length of time to produce a material containing softened bagasse fibers, bagasse pith and foreign matter, the steps of continuously advancing said material while in a wet condition downwardly through a zone of disintegration while directing sprays of water into said zone, subjecting the material in said zone simultaneously to impact disintegration, centrifugal attrition and continuous washing action so that the pith and foreign matter are loosened from the fibers without substantial disintegration of such fibers and are forced outwardly from said zone, the fibers being retained within said zone and passing generally downwardly through said zone, dis-l charging tlie pith and foreign matter passing outwardly from said zone, and separately discharging the down,-

5 wardly moving fiber relatively free of pith and foreign 1,825,307 matter from the lower end of said zone. 1,993,214 2,347,716 References Cited in the le of this patent UNITED STATES PATENTS 5 731,290 Drewsen June 16, 1903 312,554 799,434 Baker er a1 sept. 12, 1905 501,999 853,943 Drewsen May 14, 1907 1,083,102 Jackson Dec. 30, 1913 lo 1,199,241 Burton Sept. 26, 1916 1,656,829 Price Jan. 17, 192s and 35. 1,785,840 Munroe Dec. 23, 1930 6 Darling Sept. 29, 1931 Hass Mar. 5, 1935 Staege May 2, 1944 FOREIGN PATENTS Germany May 28, 1919 Great Britain Mar. 9, 1939 OTHER REFERENCES Wells et al.: Paper Trade J., Mar. 27, 1941, pp. 34

Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US731290 *Apr 13, 1903Jun 16, 1903Viggo DrewsenProcess of manufacturing products from cornstalks, sugar-cane, &c.
US799434 *Nov 5, 1904Sep 12, 1905Baker And Shevlin CompanyStock-distributer for centrifugal pulp-screens.
US853943 *Jul 9, 1903May 14, 1907Viggo DrewsenProcess of manufacturing products from cornstalks, sugar-cane, &c.
US1083102 *Mar 13, 1911Dec 30, 1913Harold JacksonMethod of preparing paper-pulp.
US1199241 *Jul 26, 1911Sep 26, 1916George D BurtonProcess of treating cornstalks and similar substances.
US1656829 *Apr 13, 1927Jan 17, 1928Theodore Price HerbertProcess of treating bagasse fibers preparatory to pulp board making
US1785840 *Apr 6, 1927Dec 23, 1930Celotex CompanyProcess for production of fibers for wall board and similar structures
US1825307 *Jun 19, 1929Sep 29, 1931Cornstalk Products Company IncProcess of producing material rich in xylan
US1993214 *Nov 21, 1932Mar 5, 1935Paul O HassThickener for pulp stock or the like
US2347716 *Jul 19, 1939May 2, 1944Black Clawson CoApparatus for screening paper stock
*DE312554C Title not available
GB501999A * Title not available
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US3013931 *Feb 1, 1957Dec 19, 1961Crown Zellerbach CorpPrinting paper and process of making the same
US3013932 *Jan 14, 1958Dec 19, 1961Crown Zellerbach CorpPrinting paper and process of making the same
US3593371 *Nov 28, 1968Jul 20, 1971Cities Service CoApparatus for producing improved pellets of a powder
US3593372 *Dec 22, 1969Jul 20, 1971Cities Service CoWet-pelletizing apparatus
US5718802 *Jan 9, 1995Feb 17, 1998Board Of Supervisors Of Louisiana State University And Agricultural And Mechanical CollegeProcess for obtaining cellulosic fiber bundles at least 2.5 cm long from plant stalk rind
Classifications
U.S. Classification162/55, 241/188.1, 241/38, 241/21, 162/96
International ClassificationD21D1/32, D21D5/18, D21B1/02
Cooperative ClassificationD21B1/025, D21D1/32, D21D5/18
European ClassificationD21D5/18, D21B1/02D, D21D1/32