DE2018878A1 - Process for making various sulphate cooking solutions - Google Patents

Description

Applicant; Stuttgart, April 18, 1970

YrjB Sivola, Ph.D, ^{P 22} ? ° ¹ ^

Dipl.-Ing. Cygnaeuksenkatu 2 B Helsinki 10 / Pinnland

Representative:

Patent attorney Dipl.-Ing, Max Bunke 7 Stuttgart Schloßstrnße 73 B

009847/1090

Process for making various sulphate cooking solutions.

This invention relates to a process for the preparation of a polysulphide-containing sulphate cooking solution by removing H _{2 S released by CO 2} from the Eestlösung obtained when the polysulphide-containing sulphate cooking solution and other sulfur-containing gases obtained from the various phases of the process as well as by burning the _{Na 9} CO ^ and Na ₉ S obtained with CO ₂ -treated residual solution.

The invention also relates to a method for the production of H ₂ S, which is used in the H ₂ S-SuIf atver. Reservation of chips is required and sulphate _{boiling solution, by removing HpS released by CO 2} from the residual solution that arises from sulphate coagulation as well as. _{Na 2} COt and Na ^ S formed by burning the _{residual CO 2} -treated solution are used.

The use of cooking solution containing polysulphide in 2Seluloseteochen has been known for quite a long time. The Zellia * - loose yield of equal strength _? ICappaaiamaer, cooked is about 5-10 fo higher than with Eoehea desselisea wood with sulphate cooli * solution, 3e after the gelialt of polysulphide in -der ICoohlöstffig «iDrots der" beeseifessWepteB, Bteigeruag öLgss yield is dag salfatkoöheii; ICeehlösvtmg · aiölrö in ia ~, Masstate oiarcfegeftllirt was © a _s because ziw Herstollstig

IsqIzl © pi? Aktiseliua iincl -ifirl-iGli ^ tlicJr Metliodeia vo ^ lageBo Yerssws & iQ with Polys'dlfiö, en ^ suA-üt: -: .. z- r: "c- ^r Ll ^; 3-»

iaiige

00884 ^ / 1030

BADORIÄAL

or sulfur added directly to the kettle while boiling cellulose. Here, polysulphide was formed as follows:

6 NaOH + 4 S = 2 Na _£ S + Na ₃ S ₂ O ₃ + 3-HgO Na ₀ S + η S = Na ₀ S

As a by-product, Na ₂ S ₂ O ^ is created, which does not take part in cooking but only increases the number of inactive chemicals. Sulfur cannot be added continuously because the result is an increase in the sulfur content in the green liquor, which causes the release of various sulfur-containing gases during burning, which pollute the surrounding air with the escaping smoke gases. The recovery of the sulfur remains low, the increase in the cellulose yield cannot compensate for the costs caused by the use of the additional sulfur. Another recommended method for preparing polysulphide is by air oxidation of the polysulphide-containing residual solution; and its use as a cooking solution together with the white liquor. Using a cooking solution prepared in this way also increases the sulphurization of the green liquor after the residual solution has been burned, which has the same disadvantages as the method indicated above. The Swedish Patent 160 736 illustrates a method _t after the polysulfide cooking-containing solution is made, but this method also "has the stated drawbacks and the economic benefits are small.

The so-called H ₂ S sulphate process has recently been tried out successfully. In this, the chips or the lignin-containing cellulose material at elevated temperature and below. Pressure with H ₂ S and a buffer solution, which is produced by buffering water ν or from an _{aqueous solution or mixture with Na 2} CO, green liquor or CACO ₃ , pretreated in the boiler or another device, e.g. as a continuous process.

009847/1090

BATH

After the pretreatment is unreacted H S _p and away from the chips is not absorbed buffer solution from the boiler or other device, either fully or partially follows whereupon the sulfate pulping process'. If one compares the H ₂ S sulphate method with the usual sulphate method, one notices considerable advantages through the former method. The cellulose yield is higher, less active alkali such as NaOH or Na _p S are required when cooking, the mass becomes lighter and easier to grind, the starch values, with the exception of the tear value, are higher. In the practical implementation of the process, however, there is a difficulty in the production of the HpS required for the pretreatment. With the help of the process described below, the technical and economical production of H _p S and sulphate cooking solution is guaranteed.

In this context, sulfuriness means the ratio of Na _p S to Na ₂ S + Na _p C (X in the green liquor is calculated as Na _p 0.

This invention relates to a process for preparing HgS and cooking solution according to claims 1 and 2. The accompanying drawing 1 and the following description show a process for preparing polysulphide-containing cooking solution by burning only concentrated residual solution obtained from polysulphide boiling. In this case, the fiber-free residual solution 1 produced by the sulphate boiling of polysulphide-containing cooking solution, which is evaporated to a certain extent in the evaporator 2, and from which residual solution soap or pine needle oil is preferably removed, is pumped through line 3 into the reactor 5, where H _p S is released from the residual solution. The device is designed so that the partial pressure of H _p S in the liquid phase remains higher than the partial pressure of H _p S in the gas phase surrounding the liquid phase, so that the removal of H ₀ S is as complete as possible.

009847/1090 ORlQfNAL

In the reactor 5 is also passed through lines 7 and 8 SCU-free smoke or lime furnace gas. Here C0 ₂ reacts with and / or NaHS in the residual solution _| and dilute hydrogen sulfide is released _{. When the gas containing dilute H 2} S leaves the reactor 5, it is sent to the ZmH ₂ S concentration reactor. Here, H ₂ S is relubricated with a suitable chemical so that HpS can be liberated from the reaction product obtained by heat in the HgS dispensing device _9, after which the H ₂ S-free solution is returned to the reactor 9. The released concentrated H ₂ S, the possibly contains some CO ₂ is discharged for further use in the various phases of the process through line 22. The chemical used _{to bind the H 2} S, from which H ₂ S is released, is returned to the reactor 9. For binding of H ₂ S you can use, for example, according to the following R _e action ":

K ₃ PQ ₄ + H ₂ S ^ K ₂ HPO ₄ + KHS

The CO ₂ leaving the reactor 9 and possibly containing some HpS can partly through lines 11-12 to the mentioned residual solution release reactor 5, and the remainder or all of the gas from the HpS concentration reactor 9 through line 11 zftipHpS absorption _Λ

I devices 14, where HgS is practically completely absorbed by the green liquor brought into contact with it from line 13. and in the upper part of which said green liquor d.iarch line 13 is pumped, the Na, -3 and 3EOiSHXX Na ₂ COn of which react with the HgS and form NaHS, ifaHCO-. The exhaust gases from the tower 14 are not discharged as such into the outside air but are treated beforehand in ^ oeii.ater Υ / ε-iue in order to veri ^ tidor pollution dex * air: », / onn nil; Hilie from CO ₀ tiMi. ιΛΛ .--- .. c Sciw-x '& l -ils HnS

is removed from the residual solution, the alkali and sulfur losses from sulphate production can be replaced by RapSO4. The residual solution from line 4 treated with COg is then returned to the evaporator 2. The concentrated residual solution that flows off through line 6 is burned, the resulting melt _{product, which essentially contains so-called active alkalis, Na 2} CCk and Na ₂ S, is dissolved, clarified and results in the so-called fermentation liquor, which enters through line 13 and which is partially or completely causticized, the so-called white liquor being produced in the causticizing agent 16. When cooking with cooking solution containing polysulphide, 10-20 $ more active alkalis than Na ₂ O, calculated on the weight of the wood, are required than in ordinary sulphate cooking. _{The Na 2} S-containing solution from line 39 required for the production of polysulphide is produced; by passing concentrated H ₂ S through the lines 22,, 23 to the device 19 in order to increase the NagS content ", in which device 19 green liquor through lines 15" 17 and white liquor through line 18, or white liquor alone, is directed.

Excess H ₂ S is returned along lines 24, 22, 25 either to the H ₂ S + S furnace 27 or to the H ₂ S and SOg-Miseli-device. 32 along lines 24-22-31 Mn Seil äes strong H ₉ S yard through lines 22-31 sum HgS uad SOg-M selige advises 32 and through lines 22-25 to the H ₂ S + S furnace 27 _a where E ₂ B is burned with air oxygen from SOr _5. , The torch line 30 zvm, H ₀ S and SOp-Mixing device 32 passed Täi ^; c! ₃ Se gleioiiQE H ₂ S -J- S furnace .. 27 if necessary Beliwef el sms'! Ioät-mg 28 Ys ^ Draaat mm from lichfeär-29 oil Hiicl Ga @ © _s die holm ICgöIigüs Püffesrij Ye & (i? J ~ : i ~.: £ en gdoiisg ■: ■ ;; ■ /; diii-üii Besipf voei EöndQasa'sati i ^ iiigöisets-t siricl, cnCi c, u.Co ', y ^ ualiWG-! ■,. • Hi ^ l't-ige gases g «s

BAD ORtGINAi,

From the gas mixer 32, the gas mixture becomes the water containing. Basreactor 37 passed "at a temperature of 50-8O ⁰ C, where sulfur is produced according to the formula below 2 H ₂ S + SO ₂ = 3 S + 2 H ₂ O

An equivalent excess amount of HpS is used in the reaction to avoid the formation of by-products. The excess HpS leaving reactor 37 and inert gases are passed to the water separator 36, of which some of the HpS-containing gas is released in the separator by conduit en3 4-3 5-31 is fed to the gas mixer 32, and the rest of the gas mentioned is led through line 34 to the concentration reactor 9. The sulfur and water released in the sulfur reactor 37 are fed to the sulfur tank 38, from which they are fed to the Polysulfide reactor 40 are passed, where the aforementioned HapS solution is passed from the device 19 along line 39 _o The mixture is mixed and heated, a polysulfide-containing solution is created in the reactor 40, which is removed through line 41 and which together with the white liquor Line 21 is used as SuIfutkochlösung ". The S Sulfur can also be added to the polysulfide reactor 40.

If the polysulfide cooking liquor containing used in connection with the Sulfatfahrikation, even halhzellulose and / or Bisulfitmasse is produced, and when the home sulfate Cooking residual solution and the remaining solution obtained from Halhzelloluse- and / or Bisulfitkocheη be fired together, the cooking liquors are ^v as follows according to i'ig. 1 manufactured.

The remaining solution, which is obtained "when oulfate cooking solution containing polysulfide is also consumed, is _{treated with CO 2} " in order to

2018876

to release the HoS from the residual solution, in accordance with Fig.l, as indicated above, whereupon it was burned together with the reagent solution from the half-cellulose and / or bisulfate cooker ο The melt obtained during the firing, the mainly Na ₂ COp and Na ₂ S contains, is dissolved, whereby Grttnlauge is produced, which comes through line 13, of which a rope or all of which is led to the H ₂ S absorption device 14. Part of the G-riinlauge leaving the device 14 is passed through line 48 to the carbon dioxide device 49, where the solution is subjected to a treatment by C © ₂ , which is contained in the S0 ₂ -free raueh or lime furnace gas. In the carbon dioxide device 49, weak HpS is released, which comes through line 50 and is passed along line 34 to the HpS concentration reactor 9. The carbon dioxide treatment produces NaHC (K, which is conducted to container 51 and then to NaHCO ^ decomposer 52, where it is _{decomposed by heat to Na 2} CO ^, which is passed through lines 55 and 57 »and to COp, which is passed through lines _{54, 55. Ea 2} CO- is passed from decomposer 52 partly or entirely through line 55 to bisulfite reactor 46, where it is allowed to react with bisulfite from line 44, so that Na ₂ SO- ^ is formed and CO ₂ passes through Line 53 is released. Some of the Na ₂ SO- formed in this way can be used as the cooking solution required when boiling half-cellulose by adding Na ₂ COo from line 55. The remainder of the Na ₂ SO- mentioned above, from line 45 is returned to the bisulfate maker 43, where it is allowed to _{react with SO 2} , which comes through lines 30-52 from the H ₂ S + S furnace 27, producing the bisulfite flowing in line 44. A part of the solution from line 44 is used as bisulfite cooking solution and the rest or all will become bisulfite reactor 46, which

009847/109 0
BATH ORIGINAL

2013878

Procedure is described above. The gas released in the NaHCO. Decomposer 52 and in the bisulfite reactor, flowing through lines 54 and 53, is passed along line 56 to the carbon diomide device 49. If all NapCO-, is not used by the NaHCO (X decomposition in Bifulfitreaktor 46 and the hemicellulose cooking liquor, the remainder Na _p CCL along line 57 is i ⁿ the 16 Kaustifikatör recycled.

The losses of chemicals in the production of semi-chemical or bisulfite celluloses can be _{compensated for by Na p} CCU, for example from direction 47 and by sulfur from direction 28.

The process for making the required for the HpS sulfate process HpS and the sulphate cooking solution according to claim 2 is in the accompanying drawing 2 and the following description. This procedure is the same as that for Pig above. I. The method described and the symbols used in FIGS. 1 and 2 are for the corresponding points are the same and are not explained further here. Only where the Pig method. 2 of the method according to Pig. I deviates, will noted the following differences:

Strong HpS containing some COp is generated by the HgS pricing device 10 passed through line 22 into the container 58, of which

H ₉ S through line 60 for pressure and heat pretreatment of the '™

Chips is brought. The green liquor used for buffering is obtained through line 63. After the HpS pretreatment of the chips, the H ^ S-containing gas from the cellulose boiler or other standard device is partly returned through lines 61, 62 to the HpS concentration reactor 9 and the rest to the H ₂ S-container 58. After removing the HgS, the pre-treatment solution not absorbed by the boiling chips is removed from the chip pre-treatment into a suitable container, from where the chip pre-treatment can be used again.

- v

e.g. after adding new green liquor "

In a continuous chip pretreatment device, preferably with indirect heating, and constructed in such a way that the pretreated chips do not contain any other solution than that absorbed before the sulphate _{boiling phase, strong H 2} S, which contains some COp, is conducted from container 58 and in larger quantities Amount than is consumed during pretreatment of the chips. At the same time, some gas is removed from the chip pre-treatment device, the amount of which corresponds to the excess gas that was introduced into the H ₂ S concentration _{reactor 9 through lines 61, 62 in order to prevent CO 2} accumulation in the chip pre-treatment phase _e The amount of buffer solution that is introduced into the chip pretreatment device corresponds to the amount of solution that goes to the sulphate boil together with the chips.

The sulphuriness of the grain length that is obtained when burning the residual solution in the H ₀ S sulfate process is lower than the sulphuridity of the green liquor obtained when burning residual solution during normal sulphate boiling, which means the almost complete removal of. To admit H ₂ S from the sest solution by means of CO ₂ , “Therefore, the sulphur- ity of the white liquor from the pipe must be in the ig. X can be increased »If HpS is released from the residual solution of the HgS-SuIfatverfuhrens to such an extent that the volatility of the & rcinla, uge _? which "is obtained during the firing of the Eestlösv.ng ₅ the sword Ii ability of the cooking solution corresponds to that in the HgS-SuIfat ^ learned © & isrkj, and since the leather production of the H ₃ S from Eochea ₉ buffers, Terdampfaii. Condensates and other phases, des SrosessQC v; irksfi: £ i; 3t _s fesnaiit the sulphurousness of the hawker slamga Im (lt.i? ät 19 aipJ'-ΐ F ^ ¹ UUeIs strong; H ₀ S arhugt zu v @ r & en _o

. 2013878

In the event that the through. COp released H ₂ S from the residual solution of the EL · S process for pretreatment: the chips and for

not enough. The increase in sulfur content in the cooking solution / is as follows Procedure applicable:

Before burning, the. For example, from line 6 coming residual solution sulfur is added in elemental form or in a suitable manner in the Brennkesseit the residual liquor. This gives the green liquor higher sulfur content. Depending on the amount of sulfur added and the increase in the sulfur content in the green liquor, there is no need to promote increasing the sulfur content in the white liquor by means of strong H ₂ S in the device 19. - {

Geuäss Pig. 2 the sulphate cooking solution is made by adding white liquor is passed through line 21 to the KocL solution tank 59, in which a part of the solution comes through line 20, the sulfuric content of which has been increased in device 19.

When the cellulose is cooked with both sulfide-containing as well as with ordinary sulphate cooking liquor in a fab Schwefligkeit the erhlaltenen by boiling of the residual solution remaining solution is lower than the Schwefligkeit by firing g

resji ™

green liquor obtained from ordinary sulphate solution. The sulphurization of the sulphurous carbon solution can be increased in the manner often described in connection with the H ₂ S sulphate process.

Recently, attempts have been made to oxidize the sulphate residue solution with atmospheric oxygen in order to convert the sulfur compounds into stable form, Na ₂ SO ^, Na ₂ S ₂ 0-> etc., thereby reducing the amount of sulphurous gases produced by Burns have occurred and pollute the bypass air. In the preparation of polysulphide-containing solution according to this invention, there is no need for oxidation

009847/1090

the remaining solution by atmospheric oxygen, since HpS and other sulphurous gases that spread bad smells and pollute the air are removed from the remaining solution. Furthermore, gases released by boiling, buffering and evaporation and condensates released by steam, as well as other sulphurous gases are emitted Line 26 burned in HpS + S furnace 27 to SO ₂ , which flows into line 30. This significantly reduces the sulphurous gases that pollute the surrounding air, while at the same time improving the recovery of sulfur.

The sulphurous gases released and changed in connection with the HpS sulphate process by boiling, buffering, evaporation and steaming of condensates are conducted through line to reactor 9 or can be incinerated in a suitable device to SOp, which reacts with the alkali of the residual solution ^ NaOH, Ra ₂ CO, or NaHCO-jy and various sulfur and sodium-containing compounds, which are returned to the residual solution incineration.

Instead of S0 ₂ -free smoke or lime kiln gases can konzenriertes CO ₂ use, which is made in previously known type of SOP-free smoke or lime kiln gas.

From the residual solution obtained from the cellulose washing, dilute H ₂ S can be separated in the reactor 5 by introducing SO ₂ -free smoke or lime-kiln gas there. Unevaporated residual solution can also be treated with strong CO ₂ .

According to Aufiraa of the foreign
Representative unchanged wcitergelsitet.

Patent attorney Burtke

98V7 / T090

Claims (1)

* 3 ■ 2013878 Patent claims: Process for the preparation of polysulphide-containing sulphate cellulose cooking solution, characterized in that the fiber-free residual solution obtained after cooking with polysulphide-containing sulphate cooking solution, which is partially evaporated and from which the soap is removed as desired, is pumped into the HpS release device for residual solution, and that S6 ₂ -free smoke or lime furnace gas is passed to the H ₂ S release device, the sulfur from Na «S and / or FaHS being released as dilute H2S from the residual solution, and the CO ₂ -treated residual solution danaeBo. is concentrated and burned, and the melt obtained by burning, which contains mainly Na ₂ CCU and Ha ₂ S, is dissolved, clarified and partially or completely causticized, and that said dilute H ₂ S in the H ₂ S concentration reactor with a suitable chemical compound reacts, from which reaction product the H ₂ S is released in concentrated form with some CO ₂ "at heat in the H ₂ S release reactor and restored, and that the _{gas leaving the H 2} S concentration reactor is passed to the H ₂ SA" absorption device , and that part of the strong H ₂ S is absorbed either in a mixture of green and white liquor or in part of the white liquor in order to increase the sulfurousness of these solutions, and that part of the strong H ₂ S mentioned is absorbed by oxygen in the H ₀ S + S furnace is burned to SOo, and that this SO «and an equivalent excess amount of said strong H ₂ S are mixed, and that this gas mowing in the sulfur reactor containing water, and that / the sulfur formed in the sulfur reactor and the water are conducted to the sulfur tank, and that a 3Jßi! of the H ₂ S containing and the sulfur BADORIGINAt / 009847 / 10S0 excess gas leaving the reactor to the above-mentioned H _? S and SO ₂ gas mixture is returned _f and that the residual gas; is passed to the HrjS concentration reactor, and that the solution with the increased content of Na ₂ S is passed to the polysulphide reactor, as well as the above-mentioned sulfur, and that a polysulphide degenerating solution is formed in the polysulphide reactor, which together with the white liquor as a cooking solution in is used in sulphate cellulose production, 2. A process for the production of hydrogen sulfide and sulfate _{cooking solution, which are required in the H 2} S sulfate process, characterized in that the _{fiber-free residual solution obtained in the H 2} S sulfate cooking, which is partially evaporated and degreased from the soap as desired, in the residual solution HpS free settlement reactor is pumped, where also SÖ ₉ -f: teies Rauchaus / or lime furnace gas, with / Τη of the residual solution Na ₂ S and / or NaHS, the sulfur is released as dilute HpS and the residual solution treated with COp is then concentrated, fired and the enamel obtained during firing, mainly NiI ₂ CO-, and Na ₂ S contains, dissolved _{s is} clarified and partially or completely causticized, and that the above-mentioned diluted H ₂ S is allowed to react with a suitable chemical compound in the HgS concentration _{reactor s} from which reaction product the HpS is allowed to react with steam in the air l'oita /
reactor in concentrated / together with something GO ₀ fxm ^ ssew! " 3E ± 32ä and restored wiränu clasa das den ύ ^ ό * ~ & 0Μϊ * Θΐ \ τ? Ϊ́ΐ ° • fiiotisreaktor irorlasseade Ctes siaa H ^ S-Absorpidene ^ Kit ^ elett ill a mistake; '■: ■■ .- ■: Qx \ l>: ^ vsiä 3-) lr- = 0m <' ^ ϋ · \ ^ ΐ: '. ^ TühiOii-:; -: i, ^v -: ■ -sl BATH ORIGINAL The sulfur content in the sulphate cellulose cooking solution can be used, and that the rest of the strong H ₂ S can be used for the serial pretreatment of chips or other lignin-containing material in a kettle or other suitable device in a slightly buffering alkaline water solution before the sulphate boiling under pressure and at elevated temperature is used, and that after the serial HpS pretreatment mentioned, the EUS-containing gas is passed partly to the Hr> S concentration reactor and partly to the HpS container, and that the "alkaline" buffer solution used during absorption after the H ₂ S - Before "treatment" and before the sulphate quenching, it is removed from the boiler (or the pretreatment device and used again as a pretreatment solution by adding new buffer solution., And that in the continuous H ₂ S-Bi; treatment of the chips under pressure and "with increased Temperature of the strong HpS, which contains a little ^ (! ^, Is poured continuously in excess into the spine pre-handling device isitet, and at the same time an amount of gas is removed from this device, which corresponds to the introduced excess amount in order to prevent the growth of COrj in the chip pretreatment phase, and that the ^ buffer solution is introduced into the chip pretreatment device together with the chips in an amount that the The amount of buffer solution that goes into the sulphate cellulose kettle. 3. Process according to claims 1 and 2, characterized in that strong CO _{2 is used in the Hest solution H 2} S decomposition reactor. 4. The method according to claims 1 and 2, thereby ■ marked that the obtained from the cellulose washing Eest solution in the EpS release oil reactor with SOg-free breath BATH ORIGINAL ¹ ° ° ^{9 8} or lime furnace gas is treated. 5. The method according to claims 1 and 2, characterized in that the residual solution obtained from the cellulose washing is treated _{in the EUS release reactor ultra strong CO 2.} 6. The method according to claims 1 -, characterized in that that the sulphurousness of the "white liquor used in normal sulphate cellulose cooking is due to kjuseiien a solution is regulated by absorption of a part strengthen/
of the restored / iLpS is obtained either in a mixture of green and white liquor or in part of the white liquor. 7. The method according to claim 1, characterized in that that the gases released by boiling, buffering, evaporation and by steam of condensates as well as other sulphurous ones Gases are directed into the HpS + S furnace where they are for use in the production of sulfur, they can be burned to SO ,, with atmospheric oxygen. 8. The method according to claim 2, characterized in that that the gases released by boiling, buffering, evaporation and by steam of condensates as well as other sulphurous gases Gases are passed into the HgS concentration reactor. 'j. Method according to patent claim 2, characterized in that the gases released by boiling, airing, evaporation and those released by steam from condensates as well as other sulfur-containing ones .; Gases in a suitable lig ^ -Verbren-. · Be directed nungsgerllt, where they are burned with Luftsauerutoff to, you daο .nit the alkali in the itest- "- ^ .v-- · '-" ■. ■ -.- 009847/1090 BATH ORIGINAL solution, NaOH, Na ₂ CO. or NaHCO ₃ , reacts to form various compounds containing sodium and sulfur, which are returned to the residual solution burner. 1Oo method according to claim 2, characterized in that to obtain the additional hydrogen sulfide necessary for the pretreatment of the chips, which also regulates the sulfur content in the sulfate boiling solution, elemental sulfur is added to the residual solution combustion _o 11 _pounds ; Method according to claim 2, characterized in that. the production of half- cellulose and / or bisulphite cooking solution ( with green liquor, which is made by the combined burning of residual liquor containing polysulphide and half-cellulose and / arises /
or bisulfite cooking solution '^ by treating part of the green liquor in the carbon dioxide device with _{gas containing CO 2} , whereby dilute H ₂ S is released, which is sent to the H ₂ S concentration reactor and may be burned to SO ₂ in concentrated form, and that Bicarbonate is produced in the carbon dioxide device, which is decomposed by heat, producing Na ₂ CO ₃ and free CO ₂ , which is produced during the oxidation of the green liquor | is moistened, and that from Na ₃ CO ₃ and the aforementioned SO _2, the half-cellulose, or bisulfite cooking solution is produced. According to the order of the foreign Representative forwarded unchanged. Potent Attorney Bunfce