US1844600A

US1844600A - Interrelated extracting and pulp-forming process and apparatus therefor

Info

Publication number: US1844600A
Application number: US358352A
Authority: US
Inventors: Reuben B Robertson
Original assignee: CHAMPION FIBRE Co
Current assignee: CHAMPION FIBRE Co
Priority date: 1929-04-26
Filing date: 1929-04-26
Publication date: 1932-02-09
Anticipated expiration: 1949-02-09

Description

Feb. 9,

, R. B. ROBERTSON 1,844,600 INTERRELATED EXTRACTING AND PULP FORMING PROCESS AND APPARATUS THEREFOR Filed April 26, 1929 /Paw raus Maer/'a/ Cmozcifor "Z0 PUMP 56mm? Web 31a/vado@ 4Q tained at Patented Feb. 9, 1932 UNITED STATES PATENT ori-ICE REUBEN `B. ROBERTSON, OF ASHEVILLE, NORTH CAROLINA, ASSIGNOR TO THE CHAMPION FIBRE COMPANY, OF CANTON, OHIO, A CORPORATION OF OHIO INTERRELATED EXTRACTING- AND PULP-FORMING PROCESS AND APPARATUS THEREFOR Application tiled April 26,

The present invention is concerned with a process of extracting a tanning substance Irom a fibrous material containing the same, and simultaneously preparing such material 5' in the form' of a pulp suitable for use in making paper or the like,and with a system of apparatus for carrying out the interre llated process. More particularly, my invention finds application 1o ment of a librousmateriaL-such for example, as the Woody parts or/and bark of oak, hemlock, Aand cl1estnut.,-containing Watersoluble constituents adapted for use as tanning agents, whereby the fibrous material aft-er extraction is in the condition of, and

possesses the characteristics. necessarily inherent ina Web-forming pulp.

According to the process heretofore known and used, the raw `fibrous material containing Water-soluble tanning agents, in its nat.

ural, relatively'dry, condition, was first reduced by mechanical nieans to a comminuted state and the coniminuted material was extracted by being brought into .contact with water on the principle of counter-current floWgfi. e., the material was brought succes- .sively -into contact with -aqueous liquid containing less and less of the tanning agent in solution and finally with pure water.

In order to secure, in a reasonable length of time, an adequate degree of removal of the tanning 'agents present in the fibrous material, it has been considered necessary to bring the material to a relatively tine state 35 of comminution. It has been the practicey to maintain the extractant at any suitable temperaturel favorable to the production of an extract of a desired degree of purity.` In those cases where the extractant was maina temperature ator above 212 F., the extraction was effected in pressure containers; at Working temperatures below 212 open tanks or tubs were employed.

This fine sub-'division Aof the fibrous material in its natural, relatively dry, state ref suitedl in the production of a product containing a large proportion off powdered material and of fibrous particles in which the ultimate fibers and fiber 4bundles were greatly shortened, with the result that, after extractto an extraction treat-` them. lVhen refined and 1929. Serial No. 358,352.

tion, the by-product fibrous material no lorger had value as a raw material for paper pu p.

An object of the present invention is the provision of an inter-related tannin-extracting and paper pulp-forming process by the carrying out of which a tanning substance may be extracted from a fibrous material containing the same, and the said fibrous material may simultaneously be prepared in the form of a pulp suitable for use in making paper or the like. v

My new process comprises the steps of Y partially or coarsely comminuting the raw fibrous material, subjecting the coarsely comminuted material to treatment with an aqueous extractant, refining the treated material and. subjecting the same to contact with an aqueous liquid, and thickening and Washing the re-treated material. A feature of the process consists in Washing the thickened material with an amount of water calculated to replace. the water lost from the system in the extract and in the washed material, and the use of this Wash water in the system for making up said losses.

The fibrous material undergoing the first extraction treatment is in a state of comminul tion suliiciently coarse-libertad to avoid material cutting or shortening of the fibers or fiber of bundles. The refining treatment is effectedv upon'the material after, the fibers'and liber bundles have become softened, hence therev iining treatment tends to separate the fibers of the bundles rather than to out or rupture 85 treated in this manner, the resulting product is in a most favorable condition for use as a paper-making pulp. In fact, a feature of. the invention consists in effecting the thickening operation by forming the refined material into a sheet, on an appropriate thickening and sheet-forming device such as, for example, a continuous suction thickener, on the cylinder mould of a paper machine or the like, of any convenient type, and washing the material with thefresh water while said material is in the sheet form. The cycli-c nature of my proce becomes apparent by tracing the water used in washing the thickened material, disregarding .the

The invention will be explained more fully by reference to the accompanying drawing,

which is a diagrammatic representation of an operable embodiment of the process and of an operable system of apparatus.

In the drawing are represented, in a closed system, in addition to the 'necessary piping, valves. and the like, a plurality of leach tanks 1 to 12, inclusive, a refiner 13, a diffusing means 14, a web-forming device 15, a pump 16. a dilute liquor storage 1T, a pump 18. and a heating means 19. 2O is a coarse comminutor. rIhe leach tanks, 1 to 12, inclusive, may be either of the open, or pressure type, depending primarily upon whether the first extraction operation is to be effected at below or above the boiling point. The said tanks are so arranged and so coupled by means of suitable piping, valves, and the like, as indicated, that an aqueous extractant, e. g., water, or wash water, can be introduced into any one tank, as into leach tank 10 in the accompanying diagram. thereafter iow continuously, as indicated, through tanks 9, 8, etc.. and,.after passing through a plurality of the leach tanks, e. g., through tanks 10 to 3, inclusive, as indicated, be discharged, as at tank 3, from the system and run to evaporators (not shown). The refiner 13. which may be any suitable known means forl opening up softened fiber bundles of pulpable fibrous material, in the presence of an aqueous liquid, such as. for instance, a rod mill or a refiner of the Jordan or Claflin types, is interposed between the leach tanks 1 to 12, inclusive, and the diffuser 14 and is connected thereto by any suitable piping. The diffusing means 14 may take the form of a` tank. or series of tanks (either open or closed, as desired), which tank or tanks conveniently may be. and preferably are. provided with some suitable means of agitation. |The purpose of the tank or tanks 14 is to provide, in a continuously operated system, a period of contact between aqueous extractant and refined fibrous material sufficient to insure'adequate extraction of tanning agents not already extracted in the leach tanks 1 to 12, inclusive. The web-forming device 15 may be any suitable known device for simultaneously thickening and forming a sheet or web, such, for instance, as the cylinder mould of a paper-making machine, or the like. The heating means 19 likewise may be any known and suitable device for transmitting heat to a liquid.

In operation, the leach tanks will contain coarsely comminuted fibrous material having progressively decreasing contents of watersoluble tanning substances; in one or more of the tanks, as 11 and 12 in the diagram, there will be fibrous material which is practically exhausted as to readily available tanning content, which material is being removed to the refiner 13 while one or more of the tanks, .as 1 and 2 in thel diagram, will be being charged with fresh coarsely comminuted fibrous material; in the intermediate leach tanks will be material undergoing the first leaching treatment with the dilute aqueous liquor from storage 17, said liquor first contacting with the nearly exhausted material in tank 10 and thereafter being brought successively into contact with material containing progressively larger proportions of the tanning substances. The resulting relatively concentrated aqueous solution of tanning substances,-i. e., the extract, or strong liquor,-is withdrawn from the system aftcr passing through tank 3 which contains freshest materialfor evaporation. Then tanks 11 and 12 have been emptied of their charge of relatively exhausted fibrous material and tanks 1 and 2 have been charged with fresh material, the tanks 10 and 9 are cut outI of the system, for discharge to the refiner 13, the aqueous extractant from storage 17 then being introduced into thel system of leach tanks first at tank 8, and passing through tanks 8 to 1,inclusive, before withdrawal to evaporation.

Thel relatively exhausted fibrous material discharged from the system of leach tanks is passed in a stream through the refiner 13 in association with dilute liquor from storage 17. thefiber bundles of the fibrous material being opened up so as to bring the same into the condition of a pulp suitable for use in making paper. The resulting stream of refined material in suspension in the liquor is then caused to pass into and through the diffuser 14 where the flow of pulp suspension is retarded to provide a' period of contact between the dilute liquor and the refined material adequate to effect thorough extraction of the tanning substances made available in the material by the refining operation.

The pulp suspension of refined and finally exhausted fibrous material flows from diffuser 14 to the web-forming device 15 where it is thickened in the known manner and simultaneously formed into. a sheet or web, and is washed thereon, in the form of a sheet, with a predetermined amount of fresh water. In the operation of thickening and washing, the weak liquor separated from the pulp is combined withl the wash Water-from the Washed pulp. The amount of freshwater added is that required "to replace the net amount of Water leaving the system in association with (1)the thickened and sheeted/pulp and (2) the extracted tanning substances in the strong 'liquor withdrawn from the system of leach y tanks.

llOA

The Weak Wash liquor and waslf Water from thefweb-forming device 15, containing in dilute solution tanning substanceswashed out of refined material, is Withdrawn by means of pump 16 to dilute liquor storage 1i', from which it is distributed, by pump 18, to several points in the cycle. One portion of dilute liquor is returned directljv to the pulp suspension from diffuser 14,-for diluting the same to a consistence suitable for application to the thickener. A second portion of dilute liquor is passed through the heating means 194 and delivered in part to the refiner 13 and in part to the system of leach tanks 1 to 12, inclusive." In case the said leach tanks areof the pressure type. a portion of the dilute liquor may by-pass the heater to the refiner; in such a case hot liquor `from the heater is delivered tothe refiner in a quantity sufficient, when mixed with the 1 unheatedliquor, to'give the entire mass the desired temperature.

lt will be seen that the process is substantially continuous and in a closed cycle of operations; that all ofthe tanning content 'of the fibrous material is conserved in the form of a relatively concentrated extract: that the fibrous by-product material is recovered in the form of a paper-making pulp;

. and that neither tanning substance nor fiber is discharged to waste. The process is simple; it Arequires a minimum amount of handling of material, of power and of labor. The'system of apparatus is of an economical character.

I claim:

1. A process for recovering water-soluble tanning substances from raw fibrous material containing the same and for simultaneously preparing said material inthe form of a paper web, which includes the following steps: (a) 'subjecting the raw fibrous material inV coarsely comminuted form to preliminary extraction with aqueous liquid obtained step o)` from step (e)- and separting the preliminai-ily extracted material from the resulting extractof water-[soluble tanniri'g substances: refining the separated material from `in the presence of aqueous liquid obtained from step ('e) and subjecting it to prolonged diffusion treatment in said liquid; (c) thickening the diffused material and simultaneously forming the same into a *paper web while retaining the-aqueous liquid separated therefrom; (d) washing the web with water; and (e) combining the Wash Water vuid from step (-0).

A process for recovering water-soluble tanning substances from raw fibrous material containing the same and for simultaneousljv preparing said material in the form Yof a paper web, which includes the following steps: (a) subjecting the raw fibrous material in coarsel)v comminuted form to preliminary extraction with heated aqueous liquid obtained from step (e) and separating the preliminarilj extracted material from the resulting extract of Water-soluble tanning substances: (b) refining the separated material from step a) in the presence of heated aqueous liquid obtained from step (e) and subjecting it to prolonged diffusion treatment in said liquid g c) diluting the diffusion mass with aqueous liquid obtained from step (e), thickening the diffused material and simultaneousljv forming the same into a paper web While retaining the aqueous liquid separated therefrom; (d) washing the web with Water;

and (e) combining the wash Water from step (rl) with the separated aqueous liquid from step (c).

3. A process for recovering `Water-soluble tanning substances from raw fibrous material containing the same and for simultaneously preparing said material in the form of a paper Web. which includes the following steps:v (a) subjecting the raw fibrous material in coarselyY comminuted form to preliminary extraction with heated aqueous liquid obtained fromstep (e) and separatingthe preliminarilv extracted material from the resulting extract of Water-soluble tanning substances; refining the separated material from step (a) in the presence of heated aqueous liquid ob tained from step (e) and subjecting it to prolonged diffusion treatment in said liquid; (c) diluting the diffusion mass with aqueous liquid obtained from step (e), thickening the diffused material and simultaneously formying the same into a paper. web while retaining the aqueous liquid separated therefrom; (d) Washing the web with an amount of fresh water equalto the total water leaving the system in the Water-Wet web and in the extract obtained in step (a)'; and (e) combining the wash water from step (d) with the separated aqueousqliquid' from step (c).

1. The process as defined in claim 1, characterized in that the extraction operation in step (a) is effected under superatmospheric pressure and at a temperature at least equal to the boiling point of water.

5. A system of apparatus for simultaneous- I V and continuously,extracting tanning substances from fibrousmaterial containing the same and preparing thel material in the form of a paper web b v the process substantiallyr as described, which comprises means for partiallv extracting fibrous material and means for delivering coarsely comminuted material thereto, a refiner receiving extracted material from said first named means, means for forminginto a web the refined material delivered thereto from the rener and for washing the 5 web, and means for delivering liquid from said Web-forming and Washing means to said extraction means and to said refining means.

6. A system of apparatus for simultaneously and continuouslT extracting tanning substances from fibrous material containing the same and preparing the material in the form of a paper web by the process substantially as described, which comprises means or partially extracting fibrous material and means for delivering coarsely comminuted fibrous material thereto, a refin'er receiving extracted material from said first named means, means for forming into a web the refined material and for Washing the web, a diffuser receiving material from said refiner and delivering material to said web-forming and Washing means, and means for delivering liquid from said Web-forming and washing means to said extraction means and to said refining means.

In testimonyl whereof@ afixmy signature.

REUBEN B. ROBERTSON.