US1402201A - Treatment of cellulose or materials containing cellulose - Google Patents

Description

M. A. ADAM, TREATMENT OF 'CELLULOSE 0R MATERIALS CONTAINING CELLULOSE,

APPLICATION HLED MAR. 9. 1920.

1,402,201 w Patented Jan. 3, 1922.

anmmboz in some 20 hours.

'ment of -Cellulose entree stares FATENT QFFWEQ TREATMENT OF CELLULOSE 03 MATERIALS CONTAINING CELLUL-OSEQ' Continuation of application Serial No. 798,451, filed October 31, 1913.

Specification of Letters Patent.

Patented Jan. 3, 1922.

This application filed Marchfl,

1920. Serial No. 864,366.

To allwhom it may concern:

Be 1t known that I, MATTHEW ATKINSON 'ADAM, a subject of the Kin of Great Britain and Ireland, residing at fiondon, England,

have invented certain new and useful Improvements in and Relating to the Treator Materials Containing Cellulose, of which the following is a specification.

This invention relates to improvementmin' processes for the chemical treatment of cellulosic materials such as Wood, which have for their object either the obtaining of morev or less pure cellulose or by action upon the cellulose or other components to produce sugar or other valuable products, and combinations of.such processes.

As the result of experiment, I have ascertained that if, in such processes, the degree of sub-division of the. solid woody material treated, the amount of liquid matter admixed therewith, Or the mechanical treatment of the mixture, or more than one of these factors be adjusted to secure durin the treatment that the mass be in the condition tal outlay, labor and fuel, available for use in such processes.

Thus I have found that by heating ground wood with bisulphite lye of standard composition to a temperature of 170 0., the pulpy mass containing say 90% of Water, the material was converted into chemical pulp in some 30 minutes, it being then appareintly free from all 'incrustingmatter and being more or less. ure cellulose. This result is only obtainab e under these conditions of temperature in present practice with a small quantity of acid and heated under pressure, the same amount of sugar as was obtainable where according to the latest proposals the acid is mixed with the sawdust in the presence of a minimum of moisture and similarly heated, and in the former case there were produced far smaller quantities of secondary products which, as is known, are a source of great trouble in attempts to ferment the sugar.

According tothe present invention therefore in the treatment of woody cellulosic materials for purposes as indicated, the materials' are before subjection to digestion brought to the condition of a fluent or mobile pulp and then preferably treated in apparatus adapted for continuous. ingress and egress of the pulp, and, if desired, regeneration of heat between the treated material and that awaiting treatment.

The accompanying drawing shows dia grammatically, how the treatment of waste wood may be carriedout in one form and in continuous apparatus according to the present invention.

k The material is transported from the heap, 1, by a conveyor, 2, to a pulverizer, 3, which may be an emery or other mill, into which it is introduced with an' approprlate' amount ofextremely dilute acid supplied from a tank, 4, through a pipe, 5. This supply of liquid is regulated so as to yield a pulp containing say 90 to 92% of water and in which the amount of acid, e. g., hydrochloric, sulphuric or sulphurous acids, is present to the extent of'some 0.5 to 2 parts by weight to' 100 parts by weight of dry wood. The pulped mass enters the pulp pit, 6, from which it is withdrawn by the feed pump, 7,

and forced into the heater or digester. This I includes a pipe, .8, having a pressure equalizer, 9, the pulp flowing alongthe pipe, 8, to the further extremity which is enclosed in the steam jacket, 9, and returning by the bend, 10, to a jacket, 11, surrounding a portion of the pipe, 8, the mass during its flow through the jacket imparting some of the heat it acquired when passing through the jacket, 9, to material flowing through the pipe 8. The pulp leaves the jacket, 11, by the pipe, 12, and is now ready to be freed of its 11 uid matter, the length oftube 8 enclose in the jacket, 9, and the. velocity of flow of the pulp having been so chosen that the pulp has been maintained for a sufiicient time, at the predetermined temperature, say,

11, having been such as to cool the material to a convenient temperature for filtration say, to 80 to 95v ;O.- v

t will be understood that if the resistance 150 (7., and the transfer of heat in the jacket,

to which the mass may be subjected. v The more or less solid mass '17 is now in the pipes from the heating region to the point of exit is insufficient to avoid ejection of the material a reducing valve or other suitable device, 13, may be lntroducedin the pipe 12.

The solid matter may now be separated from the liquid in a variety of ways, especially as the pressure required is relatively low and the necessary time short. It is best however where a certain degree of pressure is to be employed to apply this gradually rather than'to apply a heavy load at first.

In the drawing this separation is shown as effected in two stages. The material first passes onto an endles web 14 having a suction box 15 as is used in drying Wood pulp.

.During the passage of the material upon this Web, which may occupy 2 to 3 minutes or thereabouts, the liquid is drawn away by the wet air pump 16, as also any washings borne from the web 14 by rollers 18 to a press composed of'endless bands 19 and 19 gradually approaching each other and thus gradually exerting'increased pressure upon the material, the material being finally discharged at 20 after subjection during say for 2 to 5 minutes to a pressure rising to say 100 lbs. per square inch. It then contains about 50% or but little more of moisture, is fairly strong and can be gasified in a gas producer 22 to which it is fed by a conveyer, 21, to yield fuel for steam and power raising for the process.

The liquid matters from the pump 16 and the collecting tray 23 of the band press are passed by the pipe 24 to a pump 25 by which, as the liquid is still practically at the temperature at which it left the pipe 12, it is passed through thejacket 26 in order still further to save heat by transfer to the pulp flowing through the pipe 8. The more or less completely cooled liquid now leaves the system at 27 and is then treated in the known way for the recovery of" its valuable constituents.

The processmay of course be carried out in other suitable forms of apparatus. Apparatus which is well-suited to the purpose is shown in the patent to Testrup & Rigby 1,160,464 of November 16, 1915.

When applying the invention in this aspect to the manufacture of chemical 'wood pulp, the barked and trimmed logs can be ground wet in the way usual in making mechanical pulp, and preferably by the hot grinding process, when after separation of a suitable portion of the excess of water a concentrated bisulphite or other digestive agent may be added to the material and the procedure described in connection with,,pre

ceding example be adopted, the particular means. employed for eventually separating By carrying out processes of the chemical treatment of Woody cellulosic bodies on lines such as indicated, control of the rapidity, degree and course of the reaction becomes possible, and it is for example possible where the recovery of products from the liquors is sought, to minimize the forma tion of deleterious secondary products by using a lower working temperature and a corresponding greater su erincumbent pressure in the digesters. Where continuous applianc'es are used the excess pressure can for example be attained by mechanically or chemically giving artificial viscosity or pastiness to the pulp and so increasing the pressure necessary to force the matter into and from the apparatus.

Where the material is ground -in order to produce the pulp it may in certain circumstances be more advantageous to grind it dry'instead of wet as above described, particularly where no regard is paid to the fibre .length of the resulting end product or the product is required as wood meal or for like purpose. The dry grinding 'gives a productofextreme fineness and one therefore especially susceptible to rapid action. It may be convenient where the raw product, e. g., waste wood, sawdust, is of mixed character to screen it, and to treat in separate units the portion composed of fine particles, this giving rapidly the desired result andyielding the fuel material for the process, while the coarse material yields after treatment material of'sufliciently long-fibre to be available for paper making;

It is important to observe that apart from moisture content and degree of subdivision of the material, mechanical beating or pulping can be brought to play a largepart in the roduction of the'pulp and in particular in t e homogenizing of the materlal.

It should be observed that when employing apparatus through which the material continuouslfy flows as described all the advantages 0 quick heating and cooling are obtained without however the walls of the digester varying in temperature so that at all points during workin the temperature remains practically invarlable, and lead or other linlngs can be safel employed'without fear of rupture or buc in v By the expression in a finely subdivided form in the applended claims, it is to be understood that t e same refers to material which is ulverized or of such fineness that itis capa le upon intimate mixing with water of forming a true pulp, which will flow freely. It will be readily understood that this condition is not practicallyattainable with the use of cellulosic materials which are coarser in their nature than relatively fine sawdust.

This application is a continuation of my p)rior application Serial No. 798,451, filed ctober 31, 1913, and is filed in substitution thereof.

I claim:

- drolysis.

digester-while maintaining therein sufiicient heat and pressure to accomplish the desired digestion, and passing the pulp directly from the digester to heat regenerating means.

3. In the process of hydrolyzing cellulosic materials, the steps which consist in commingling the cellulosic materialin subdivided form with sufficient water to form therewith a fluent pulp and with a hydrolyzing agent, and subsequently passing the said pulp continously through a suitable 'digester while maintaining therein suflicient heat and pressure to accomplish the desired hydrolysis. v

4. In a process of making sugar from cellulose, the steps which consist in commingling cellulosic material in subdivided form with suflicient water to form therewith a fluent pulp and with an acid hydrolyzing agent, and subsequently passing the said pulp continuously through a suitable digester while maintaining therein suflicient heat and pressure to accomplish the desired hy- 5, A method of hydrolyzing wood consistmg in grinding the. sameto a fine condi- 'tion of subdivision to producea pulp with a hydrolyzing liquid with which it is admixed, the pu p then with all of its water being continuous y heat regenerating elements and the liquid forced through heating and matter being then separated from the solid matter; at set forth.

6. A method of treating woody cellulosic materials comprising reduction to pulp with an added chemical digestive agent heating the pulp under pressure, forcing the treated pulp with all its water through heating and heat regenerating elements, thereby cooling the same to a temperature suitable for filtration, separating the liquid matter from the solid matter and recovering the heat of the separated liquid matter by means of heat regenerating elements.

7. A method of treating woody cellulosic materials comprising reduction to pulp with an added chemical digestive agent heating the pulp under pressure, forcing the treated pulp through heating and heat regenerating elements, thereby cooling the same to a temperature suitable for filtration, separating the liquid matter from the solid matter, re

covering the heat from the separated liquid matter by means of heat regenerating ele ments and utilizing the solid matter for the production of heat for the heating elements.

8. A method for the economic manufacture of sugar from woody cellulosic materials comprising the reduction to pulp with an added acid, subjecting the pulp to heat and pressure, separating the liquid matter from the solid matter, recovering heat from the separated liquid matter and utilizing the solid matter for the production of heat in the process.

9. The method herein described of treating wood, consisting in grinding the wood while subjected to an acid solution to form a pulp, heating the pulp to digest the same, removing a portion of the liquid, subjecting the mass to pressure, and then delivering the solid material to a gas producer.

10. The method herein described of treating'wood, consisting in grinding the wood while subjected to an acid solution to form a pulp, subjecting the pulp to the action of heat to digest the pulp, removing a portlon of the liquid, subjecting the'mass to pressure, delivering the solid material to a gas producer, and utilizing the extracted liquid to assist in heating the pulp. .In testimony whereof I afiix my signature.

MATTHEW ANSON ADAM.

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