US1864220A - Paper manufacture - Google Patents

Description

June 21, 1932.

H. T. RUF F PAPER MANUFACTURE Filed April 14. 1930 Patented June 21, 1932 UNITED STATI- 2s PATENroFFlcE HAROLD T. BUFF, OIF CHILLICOTHE, OHIO, ASSIG'NOB. TO THE MEAD RESEARCH4 ENGINEERING COMPANY, OF DAYTON, OHIO, A CORPORATION F OHIO PAPER HANUFACTURE Application led April 14,

This invention relates to the manufacture of paper, and particularly to the treatment of fibrous material in the roduction of pulp.

One of the principal o jects of the inven- 5 tion is to provide a' method for efectlvely and economically treating fibrous material with a halogenating agent in the manufacture of ul p Aliiother object of this invention is to provide a method of chlorinating fibrous material at high consistency with a gaseous chlorinating agent, which permits of controlled and effective treatment, with high economy in the 'use of the chlorinating agent.

Still another object of the invention isto provide apparatus for carrying out the above method, which apparatus is simple in construction, highly efective in operation, providing accurate control with a uniform production of treated fibrousI material, while insuring against the escape of objectionable fumes. y

Other objects and advantages of the invention will be apparent from the following description when taken in connection with the accompanying .drawing and appended claims.

In the drawing, the single gure is adiagrammatic elevational view, partly in section. of apparatus: constructed for carrying out the method of this invention.

The invention isl appliible to the chlorinating treatment of, fib'ro yn iaterials generally, such as wood, fst fibrous grasses and analogous materia the manufacture of pulp or analogousmaterials? 'ItQissuitable for the treatment- "ghiyiignified fibrous material, andi- I i p only for bleaching, butfalso as aplllfping step in the disintegration ofundefibered material. For example','f which has been given a preliminar plete or partial digestion orsteeping. to iucompletely remove non-fibrousibon constituents, can then be subjectedgtfrthe treatment of this invention 'to effect pulping and removal of such,vnon.fi.bro1' con# stituents. The invention`- is also, applicable generally for bleaching pulp orfibrous material, Aor for any pulpinglor bleaching proper manipulation of the valves Q6.

r The presentv invention is particularly adapted for the treatment of fibrous material i v[with a gaseous halogenating'agent, such asv gfclhlorine gas. For themosteffective opera- 1930. serial No. 444,075.

process involving gas chlorination as a `step thereof.

Referring to the drawing, in which a preferred embodiment of the invention is illustrated, a plurality of chlorinating chambers are mounted in alignment, four chambers being shown at 10, 11, 12 and 13 respectively. Each chamber comprises a shell constructed of acid proof ymaterial such as tile, the size of the shell depending upon `the desired capacity of 'the particular plant and the number of chambers used. The shell is provided with an opening 11 in the upper portion thereof closed by a removable cover 12. Preferably the cover 12 is water sealed, such a5 as by providing flanges 13 and 14 on the top of the chamber to form an annular basin for containing a sealing liquidwithin whichv the cover 12 dips. Fibrous stock to be treated is supplied from a bin or storage tank14 through thechute 15 to a conveyor 16, shown as an open trough -17 having mounted therein a longitudinal shaft 18 driven by a pulley or gear 19 from any suitable source of power, the shaft carrying a helical screw 20 for progressively feeding the brous material along the trough. The commori conveyor 16 is arranged above the chlorinating chambers 10-13 in alignment therewith, and is provided at spaced points with a plurality of downwardly depending chutes 21-24 adapted to introduce the fibrous ma-l terial into the several chambers 10-13 when the respective covers 12 .are removed. Each chute communicates with trough 17 by an 85 opening 25 in the bottom wall thereof, this opening being controlled by a suitable slide valve 26. so that the fibrous materialmay be selectively fed to each` of the chambers by tion, the fibrous material is preferably`sup= im`Y fp'lied at a high consistency such as to be readily permeable to gas. For example, fibrous material, or pulp stock, at a consistency in excess/of 15% gives very satisfactory results. This material is readily handled by the screw form distribution of the chlorinating agent through the fibrous material therein.

Gas oiftakes 42-45 having respective control valves 46-49 communicate with a common suction main 50 leading to a suitable source of suction such as a suction pump 51. Each of the gas oiftakes preferably communicates with the upper portion of its respective chlorinating chamber, so that the introduction of chlorine gas into the fibrous material may be assisted by connecting the re a spective oiftake at the upper portion of the chamber to the suction pump 51, whereby the air within the chamber is exhausted and the chlorine gas uniformly introduced in a rising column within the chamber.

The respective chlorinating chambers are also provided with pipe connections 52-55 having respective control valves 56-59 communicating with the lower portions of each of the chlorinating vchambers and connecting to a common by-pass main 60. dEach chamber is also provided, preferably adjacent the upper end thereof, with a pipe 62 controlled by a suitable valve 63 which opens to atmosphere or communicates with a suitable source of inert Iiuid, such as a gas or vapor which does not objectionably react with the chlorinated material or pulp. Adjacent the lower end thereof, each chamber is provided with a pipe 65 controlled by a valve 66 communicating with a source of water or other suitable slushing liquid under pressure.

In operation, assuming the chamber 10 is to be supplied with fibrous materia-l, the cover 12 is removed and the valve 26 opened, so that the operation of the screw conveyor 16 serves to feed fibrous material through chute 21 into the chamber 10 until it is substantially filled. The cover 12 is then replaced, valve 26 closed, and then the cover 12 of another chamber such as chamber 11 is removed and the valve of chute 22 opened so that fibrous material may then be supplied to this chamber while the chlorinating operation proceeds in chamber 10. This is accomplished by opening valves 31, 36 and 46, so that the chamber 10 is connected to the suction pump'and to the chlorine gas main, the chlorine gas thus being drawn into the chamber` through 'the perforated distribution pipe 40 until the level of the gas appears above the fibrous material within the chamber, as can be determined by a suitable sight glass or gage. It is not essential that the chamber be connected to the suction pump during the introduction of the chlorine ygas or other' chlorinating agent, but this is preferred in order to minimize the danger of gas leakage. The fact that the chlorine is drawn into the chamber under subatmospherie pressure insures against escape of gas from the chamber with resultant contamination of the surrounding atmosphere., When the chamber is properly lled or supplied with chlorinating gas, the valves 36 and 46 are then closed, and the chamber 10 allowed to stand for a suitable time, such as about 2O minutes, to permit the chlorinating action to proceed to substantial completion. Sufficient chlorine gas is supplied to the chamber to insure the substantially complete chlorination of the fibrous material therein.

In the meantime, chamber 11 has been filled with fibrous material and the cover of this chamber replaced, chamber 12 then being supplied and filled with the fibrous material, so that substantially continuous operation of the screw conveyor and the continuous and uniform feeding of the fibrous material from the common conveyor to one of the chambers is secured. Valves 56, 57v and 47 are then opened, so that chamber 11 is connected with suction main by the offtake 43, and the lower portions of chambers 10 and 11 are connected with each other through the by-pass main 60. At this time, valve 63 is also opened so that an inert fiuidsuch as air is drawn into the upper portion of chamber 10 through the pipe connection 62, or this may be permitted by loosening the cover 12 and permitting air to pass in around the loosened cover. The suction pump 51 then draws this air down through the fibrous material within the chamber 10, serving to drive. out excesschlorine gas remaining in the material, the mixed -air and excess chlorine gas passing through the by-pass main into the lower portion of the chamber 11. This mixed gas is then drawn up through the fresh untreated fibrous material within: chamber 11, so that the chlorine gas contained in this gaseous mixture is absorbed by and reacts with the fibrous material therein.

As the reaction of the fibrous material with chlorine gas is very rapid, substantially all of the chlorine in this gaseous mixture is immediatelyl absorbed by and used in reaction with the fibrous material. Thus the excess chlorine gas is effectively removed from the treated fibrous material in chamber 10, and economy is secured by the use o f this gas in treating additional fibrous material in chamber 1:1. The remaining air and otherfiuid passes through the offtake 43 to the suction main 50 and is discharged to atmosphere or suitable main. This washing of the treated previouslv described for chambers 10 and l1.

Y Lenaweev fibrous material in chamber 10 is continued until substantially all the excess chlorinating agent is removed therefrom. The valves 63, 56 and 57 are then closed, and the valve 37 is opened, so that additional chlorine gas is supplied from main 30 to the distribution pipe 40 of chamber 11 until this chamber is supplied with the desired quantity of chlorine gas for the completion of the chlorinating action therein.

Valve 66 is opened in the meantime to permit water or other slashing liquid to be introduced into the lower portion of chamber 10 to dilute the treated stock therein and to slush it out through a discharge opening 70 controlled by a suitable valve 71 in the base of the chamber. Preferably the discharge 70` is also water sealed during operation, which may be conveniently accomplished by the provision of a small water pipe 71 for introducing a small amount of water above the valve 71 prior to the chlorinating operation. The fibrous material of high consistency within the chamber 10 moves downwardl therein by gravity as material at the bottom is slushed out from the chamber. This diluted stock discharges through a suitable chute 72 into an inclined trough 72 which extends longitudinally beneath the several chlorinating chambers. The discharge openings 7() of these several chambers, which are controlled by valve 71 vin the manner 'of chamber 10, also feed through suitable chutes 72 into the trough 73, so that a common discharge conveyor or trough receives the treated material discharged from the severall chambers and leads this material to a suitable stock chest (not shown).

During the emptying of the chamber 10, the chlorination of the fibrous material in chamber 11 proceeds to completion, while chamber 12 is filled with fibrous material or stock to be treated. The valves 37 and 47 having been closed when sufficient chlorine has been introduced into chamber 11, then at the completion of the chlorinating action therein, the valves 57 58 and 48 are opened and also valve 63 of chamber 11. so that air is drawn into and through the fibrous material within chamber 11 to wash out the excess chlorine gas from the fibrous material therein, the mixed air and chlorine gas passing through the by-pass main 60l into the lower portion of chamber 12 in the manner During this time. chamber 13 is being filled with fresh fibrous material, while the emptying' operation of chamber 10 is being completed. This operation is then repeated for chambers 12 and 13, so that the excess Chlorine gas washed out of the fibrous material in chamber 12 is absorbed by and reacts with the fibrous material 'in chamber 13; and then in the next stage of'operations chambers 10 and 13 are connected by the by-pass main 60 so that the excess chlorine gas'i'washed out While a smaller or larger number of chlorinating chambers can 'of course be used, preferably 'at least four such chambers are connected in a unit as shown, so that two of the chambers may be connected through the bypass main for washing action. of the'chlorinating material in one chamber and the absorbing of the excess chlorine gas driven off of that material by the additional fibrous material in the other chamber, the third chamber at this time being emptied of treated fibrous material, and the fourth chamber being filled. A substantially continuous supply of the fibrous material to one of the chambers is thus permitted by the common feeding conveyor 16, and a uniform discharge of treated fibrous material from one of the y chambers is received during operation by the trough 7 3 and supplied to a stock chest for further treatment. vOther suitable gaseous halogenating 0r chlorinating agents can be used in accordance with this invention, such as gaseous bromine, or chlorine gas mixed with other gases. For example. a mixture of chlorine and air may be used to give a less active chlorinating reaction.

This invention thus provides a convenient means of treating shredded or cooked lignified fibrous material, or pulped material, with a gaseous halogenating agent to effect further pulping, or bleaching, or both pulping and bleaching. The use of a non-halogenating agent such as air in order to displace the excess gaseous halogenating agent such as lgaseous chlorine. is found an effective means of washing the pulp without the necessity of liquid washing. or the employment of apparatus other than tbe chlorinating chamber which can be satisfactorily lined or made of acid-proof material to resist corrosion.

Such air washing very efciently removes excess chlorinating agent, leaving at most only a. very small Quantity which is absorbed bv the pulp in a short reaction time. Any small residual ouantity of free chlorine left in the pulp can be neutralized bv the addition of a small amount of some suitable anti-Chlor in the well known manner. In this manner, itis possible to insure that no free chlorine remains in the pulp adlnixed with the reaction products of the chlorination. which` reaction productsfcontain a large percentage of hydrochloric acid. Such mixture of reaction products with free chlorine produces a very f.

objectionable free chlorine is effectively`elimiuated from the pulp and reaction products prior to removal from the chlorination chamber. thus rendering the subsequent treatment free from corrosion ('lifficulties. The preliminary treatment of lignified fibrous material with chlorine gas substantially diluted with air has the advantagl;l of providing for control of the chlorination reaction,` avoiding objectionable local overheating with consequent iniury of the cellulose.l fibers. After the preliminary incomplete chlorination in this manner. the fibrous material can then be treated with more concentrated or substantially pure chlorine gas Without objectionable results'. providing for the completion of the chlorinating reaction in an effective manner. The process provides for the use of an excess of chlorine for the final chlorinating step. and at the same time provides for economical utilization of this excess of the chlorinating agent without necessitating an elaborate recovery system.

lVhile the method herein described, and the form of apparatus for carrying this method into effect. constitute preferred embodiments of the invention, it is to be understood that the in-yention is not limited to this precise method andform of apparatus. and that changes may be made in either Without departing from the scope of the invention which is defined in the appended claims.

lVhat is claimed is:

l. In the manufacture of pulp, the method which comprises subiecting fibrous material to treatment with a halogen, then-passing a fiuid through the treated fibrous material to drive out excess halogen, and passing the mixed fluid and halogen discharging from said fibrous material through additional fibrous materi alto thereby use the excess halogen in treating the additional fibrous material.

2. In the manufacture of pulp, the method which comprises subjecting fibrous material to treatment with a gaseous halogen. then passing a fluid through the treated fibrous material to drive out-excess halogen, passing the mixed fiuid and halogen discharging from said fibrous material through additional fibrous material to thereby use the excess halogen in treating the additional fibrousV tional fibrous material tothereby use the excess halogen in treating the additional fibrous material` continuing thc passing of the `fiuid until the first mentioned fibrous material is substantially free of excess halogen, then introducing a liquid into the first mentioned fibrous material to dilute this material and to slush it out of the treating zone, and subjecting the additional fibrous material to further treatment with a gaseous halogen.

4. In the manufacture of pulp, the method which comprises subjecting fibrous material at a high'consistency such as to be readily permeable to gas to treatment with chlorine gas, then passing air through the treated fibrous material to drive out excess chlorine gas therefrom. and passing the mixed air and excess chlorine gas discharged from the treated fibrous material through additional fibrous material to thereby use the excess chlorine gas in the treatment of the additional fibrous material.

5. In the manufacture of pulp, the method which comprises subjecting fibrous material at a high consistency such as to be readil;1 permeable to gas to treatment with chlorine gas, then passing air through the treated fibrous material to drive out excess chlorine gas therefrom, and passing the mixed air and excess chlorine gas discharged from the treated fibrous material through additional fibrous material to thereby use the excess chlorine gas in the treatment of the additional fibrous material` continuing the passing of the. air until the first mentioned fibrous material is substantially free of excess chlorine gas. then removing the first mentioned treated material. and subiecting the. additional fibrous material to further treatment with chlorine gas.

6. Apparatus of the character described adapted for the treatment of fibrous material in the manufacture of pulp, comprising a plurality of chambers. means for supplying fibrous material thereto. means for supplying a halogenating agent to one of said chambers. means for supplying a Washing fluid to said chamber to drive off excess halogenating agent from the fibrous material therein, an oft'take for the mixed Washing fluid and excess halogenating agent driven ofi' from saidchamber, and a connection communicating with said offtake for introducing said mixed Washing fiuid and said halogenating agent into aseoond chamber into contact with fibrous material therein.

7. Apparatus of the character described adapted for the treatment of fibrous material in the manufacture of pulp, comprising a plurality of chambers, means for supplying fibrous material thereto, means for supplying a gaseous halogenating agent to one of said chambers, means for supplying a washing fiuid to said chamber to drive off;` excess halogenating agent from the fibrous material therein, anpotake for the mixed washing fluid and excess halogenating agent driven ofi from said chamber, a connection communicatin with said offtake for introducing said mixed washing iiuid and said halogenating a ent into a second chamber into contact with firous material therein, means for the removal of treated fibrous material from said first mentioned chamber, and means for supplying additional gaseous halogenating agent to said second chamber.

8. Apparatus of the character described adapted for the treatment of fibrous material in the manufacture of pulp, comprising a plurality of chambers, means for supplying fibrous material thereto, means for introducing a halogenating agent to one of said chambers, means for supplying an inert gas to said chamber to drive off excess halogenating agent from the fibrous material therein, an otake for the mixed inert gas and excess halogenating agent driven o from said chamber, a connection communicating with said offtake for introducing said mixed inert gas and excess halogenating agent into a second chamber into contact with fibrous material therein, means for introducing'a liquid into said first mentioned chamber to slush out treated material therefrom, and means for supplying additional halogenating agent to said second chamber.

9. Apparatus of the character described adapted for the treatment of fibrous material in Vthe manufacture of pulp, comprising a plurality of chambers, means for introducing brous material into each of said chambers, valve controlled inlets for the introduction of chlorine gas into each of said chambers, valve controlled offtakes for each of said chambers, suction means connected to said offtakes, means for introducing air into one of said chambers, and a connection between said iirst chamber and a second chamber, whereby said suction means is adapted to draw air into said first chamber and through the treated fibrous material therein to wash out excess chlorine gas from said fibrous material, the mixed air and excess chlorine gas then being drawn through said connection into said second chamber and into Contact with fibrous material therein, the remaining fluid passing through the ofi'take of said second chamber to said suction means.

l0. Apparatus of the character described adapted for the treatment of fibrous material in the manufacture of pulp, comprising a plurality of chambers,.means for introducing brous material into each of said chambers, valve controlled inlets for the introduction of chlorine gas into each of said chambers, valve controlled oitakes communicating with the upper portions of each of said chambers, suction means connected to said -oii'takes, means for introducing air adjacent the upper portion of one of said chambers,

and a connection between the lower portion of said one chamber and the lower portion of a second chamber, whereby said 'suction means is adapted -to draw air into said first chamber `and through the treated fibrous material therein to wash out excessl chlorine gas from said fibrous material, the mixed air and excess chlorine gas then being drawn through said connection into said second chamber and into contact with fibrous material therein, the remaining fluid passing through the offtake of' said second chamber to said suction means.

11. Apparatusof the character described adapted for the treatment of fibrous material in the manufacture of pulp, comprising a plurality of chambers, a common supplying meansfor fibrous material, means for selectivelycontrolling the feeding of fibrous material from said common supplying means to each of said chambers, a common maln for halogenating agent, and means for selectively controlling the supplying of halogenating agent from said main to each of said chamers.

12. Apparatus of the character described adapted for the treatment of fibrous material in the manufacture of pulp, comprising a plurality of chambers, means for sup lying fibrous material to each of said chambers, a common chlorine gas main, means for selectively controlling the supplying of chlorine gas from said main to'ea-ch of said chambers, a common suction main, a suction means therein, and means for selectively controlling communication of each of said chambers with'said common suction main.

13. Apparatus of the character described adapted for the treatment of brous material in the manufacture Ofpulp, comprising a plurality of chambers, means for supplying fibrous material to each of said chambers, a common chlorine gas main, means for selectively controlling the supplying of chlorine gas from said main to .each of said chambers,

a common suction main, a suction means therein, means for selectively controlling communication of each of said chambers with said common suction main, means for selectively introducing air into each of said chambers, 'and means for the passage of gaseous products from one of said chambers to another.

14. Apparatus of the character described adapted for the treatment of fibrous material in the manufacture of pulp, comprising a plurality of chambers, means for supplying fibrous material to each of said chambers, a common chlorine gas main, means for selectively controlling the supplying of chlorine gas from said main to each of said chambers, a common suction main, a suction means therein, means for selectively controlling communication of each of said chamberswith said common suction main, means for selectively introducing air into each of said chambers, a common by-pass main, and valve controlled connections between each ofv said chambers and said by-pass main,

15. Apparatus of the character described adapted for the treatment of fibrous material in the manufacture of pulp, comprising a plurality of chambers, a common supplying means for fibrous material, means for selectively controlling the feeding of fibrous mateP rial from said common supplying means to each of said chambers, a common chlorine gas main, means for selectively controllingthe supplying of chlorine gas from said main to each of sald chambers, a common suction main, a suction means therein, means for selectively controlling communication of each of said chambers with said common suction main, means for selectively introducing air into each'of said chambers, a common bypass main, valve controlled connections between each of said chambers and said b -pass main, and means for removing treated brous material from each of said chambers.

16. Apparatus of the character described ada ted for the treatment-ofiibrous material in t e manufacture-of pulp, comprising at least vfour chambers, means for suppl ing fibrous material to each of said cham ers, means for selectively supplying gaseous chlorine to said chambers, means for selectively introducing air into said chambers, means for passing gaseous products from one of said chambersto another, and means for removing treated fibrous material from each of said chambers, the arrangement be' such that two of said chambers areadapte to be placed in communication so that air and excess chlorine gas ma be passed from the treated fibrous materia in one chamber into the untreated fibrous material in another the 'treating the said l ,excess of moreconcentrated chlorine gas to -the removed excess of chlorine 1n with a chlorine gas admixed with a substani `tial proportion of air as a diluent, and subsequently treating the fibrous material with a substantially more concentrated'chlorine as. 20. In the manufacture of ulp, the met 10d which comprises treating Ebrous material with an excess of a gaseous halogenating agent, so that at the completion of the halogenating reaction a substantial amount of the aseous halogenating agent remains in brous ,material, removm such excess halogenating a nt in gaseous orm from the p fibrous materia and passing removed gaseous halo natin agent'into reaction contact with ad tional brous materiah 21. Inthe manufacture of pul the meth which com rises first treatin brous material with c orine as dilute with air, then brous material with an complete ythe chlorinat'ing reaction, removing the excess chlorine 1n gaseous form from the chlorinated fibrous material, and passing form into lcontact with additional fibrous material.

In testimony whereof I hereto aiiix my signature. Y

Y HAROLD T. RUFF.

chamber, while a, third chamber is bein sup- .i

gulp, the method which comprises treating brous material with a gaseous halogenatingagent'admixed with a substantial proportion of a non-halogenating aseous diluent, and subsequently treating t e fibrous material with a more concentrated gaseous halogenating agent. 18. In the manufacture of 1plulp, the method which' comprises treating brous material with a gaseous halogenating agent admixed with a substantial proportion'of a non-halogenating gaseous diluent, the quantity of gaseous halogenating agent used in this treatment being insufficient to effect complete halogenation of the librous material, and` subsequently completing the halogenating of the fibrous material by treatment with an excess of a more concentrated gaseous halogenating agent.

19. In the manufacture of pulp, the method i `which comprises treating fibrous material gaseous Ifil-

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