DE413318C - Process for the production of paper from straw-like raw materials - Google Patents

Description

Process for the production of paper from straw-like raw materials. object the invention forms a method for producing paper, in particular from straw-like raw materials, such as B. corn, wheat, rye, barley, oat, rice, Millet, buckwheat, rapeseed, clover, alfalfa, vetch, sweet clover, bean, pea and lentil straw, the leafy stalks of the reeds, hops, nettles and anything else from all vegetable raw materials that are not woody in structure.

The new procedure. breaks down into a mechanical and a chemical one Treatment of the raw material to break it down by cooking and treating of the digested pulp for paper production. The paper production itself takes place in a known manner.

Processes for paper production from straw-like raw materials are already in place known. These processes have the disadvantage that they have special properties of the straw-like raw material are not so adapted to the economic Production of cheaper types of paper for mass consumption only or almost exclusively to enable straw-like rob fabrics.

The characteristics that make the new process stand out from the familiar differs, consist essentially in the following: The raw material is initially through Pressure, bending and torsional stresses squashed and only then chopped up, that Before the subsequent cooking, the chop is accelerated by the addition of heat Subjected to souring and then first boiled with water, then with lye, that, in both cooking processes, the temperature and when cooking with lye too the concentration of the lye can be increased. The digested pulp will between wood, rubber, horn, leather or the like, soft but elastic and tough material milled grinding tools. To produce inferior Paper types can still contain the wastewater from washing, grinding, sorting and of bleaching the fabric repeatedly for the same operation.

By .this method is compared to the known in time, heat and lye saved, dead grinding of the material avoided and through the return line the wastewater also recovered the inferior cell types for paper stuff.

According to the new process, the raw material is first subjected to pressure, bending and torsional stress squeezed, d. i. mainly split lengthways and only then chopped up, d. i. by cutting or shearing in the transverse direction crushed. By means of the associated sorting process, the chaff is simultaneously from the coarse impurities that are harmful to paper production (pieces of soil, Grains, knots, etc.).

This mechanical preparation of the raw material can be carried out using the methods shown in Fig. r and a shown device are carried out. The raw material gets through first the lath table r fed to a pair of pressure rollers z, 3, its surface is provided with small conical projections. With 4, 5 is the pair of crushing rollers referred to, whose individual, axially ribbed rollers mesh with one another similar to the gears and especially crush the harder parts of the fabric. The next Rollers 6, 7 are provided with helically extending ribs, which cross in the plane of contact in order to produce a turning effect. The one in the longitudinal direction split fabric is now. by pair of rollers 8, 9 and guide roller io of the fixed Knife i i and on the drum i.1 rotating knives 12 existing chopping device fed. For the purpose of sorting the chopped material, the drum 14 can be used as a wind reel be formed.

The material thrown in the direction 15 becomes specific Weight sorted collected at points 16-2o. The segregation of the various Components can e.g. B. can be regulated by adjustable butt plates 21-24. A- more efficient sorting can be achieved through the use of underwind, which is fed by fan 29 to locations 25-28.

The method described is compared to the known method Chaff with a larger surface area for chemical digestion, namely with relatively little work and little damage to the fiber stock obtain. The chaff is also significant, more poundable, which means that the cooker space and Thermal energy is saved.

The cleaned chaff is then closed when it is moist Natural acidification accelerated by the application of heat, d. i. a similar one Fermentation process, like this one that is common in agriculture The beet cuttings, the green fodder, the corn stalks, etc. are acidified and which by the various types of fissure fungi that adhere to the property (the lactic acid, butyric acid, propionic acid, etc. fermentation) is effected. The fermentation process is accelerated in the sense of the invention in such a way that the in the closed space crushed moist chaff immediately at the beginning of the fermentation on that of the fermentation most advantageous temperature (4o to 55 ° C) heated and this temperature during the whole, acidification is maintained until the end.

The souring of the chaff can, for. B. happen in vertical shafts according to Fig.3 to 5. The shaft 30, which is double-walled for the purpose of good thermal insulation, is filled from above through the opening which can be closed with a double cover 33, 34. The bottom of the shaft is formed by a grate surface 3, through which on the one hand any liquid that may seep down from the chaff can drip through and be collected in a pan 38, and on the other hand the water vapors rising from this pan, which is filled with water and heated from below, into the chaff can penetrate. Pan 38 can be filled with water through a pipe or valve 41. 42 is the overflow pipe, 43 is the drain pipe of the pan. Radiator systems 39 and 4o are attached below the pan, to which the hot water or steam used for heating is fed through pipes or valves 44 and 45, while the waste water is led away through pipes 46 and 47. In order to be able to observe the temperature prevailing in the shaft during acidification, thermometers are inserted through the openings 48 and 49 into the chop in such a way that the openings are also tightly sealed. On the upper double cover of the shaft ventilation valves 5o, 51 are arranged, which open when there is excess pressure. If several shafts are used, they can be assembled like batteries according to the dots in Fig. 4 and 5.

The operation of the device described is as follows: First the pan 38 is filled with N water and only then is the crushing of the chaff began. At the same time, heating up with the radiator systems is started. It is controlled by valves 44 and 45 so that simultaneously with the termination after filling or shortly afterwards, the chopped up chopped up to the required temperature (about 40 ° C) is warmed up. The temperature is in the fully filled shaft during the acidification constantly maintained, between 4o to 55 ° C, which Temperatures on the two thermometers 48 and 49 can be monitored.

The water in the pan 38 is used to replace and maintain the wetness of the crushed chaff up to the end of the acidification. To good Success. To achieve this, the water content of the chop should be 6o to 75 percent (resp. calculated on dry matter i 5o to 3oo percent). Should be air dry Chops (13 to i 8 percent water content) are processed, so it will be before Artificially moisten the pulping.

Moist chaff containing 70 to 12 kg of dry matter can be pulped into 1 cbm of shaft space. A shaft with a capacity of 2o to 40 cbm can be placed in; 3 to 5 hours filled with crushed moist chaff and heated at the same time. The acidification that follows takes between 30 and 50 hours. In general, one becomes with thick and hard-stemmed types of straw or with better ones. Paper types approximate the longer, with thinnest straw types the shorter acidification time.

For the purposes of the invention, waste heat can also be used during acidification by using exhaust steam or the heat of the condensed water to heat the shaft of the company is used.

By acidifying the chop before cooking, on the one hand, the Fiber already opened up to a certain extent by this, on the other hand the. Tampability of the chaff further increased. As a result, you need to unlock it once and for all with the next boiling, smaller stove space, shorter time and less Heat and amount of lye.

The acidified chaff is in a closed cooking room temperature exceeding ioo 'C, i.e. i Atm. excessive pressure, first with water, then after the solution created by boiling with water from the food . Removed, with excess lye until the pulp was broken down cooked. In the context of the invention, the temperature and, as a result, the pressure as well in the cooking area for both cooking processes and also when cooking with lye The concentration of the lye increased during the entire cooking process.

The increase in pressure and concentration is shown in Fig. 6. The time is plotted as the abscissa, the pressure (overpressure in atmospheres) in the cooking chamber and the lye concentration as the ordinate, so that curves P1 and P ° show the increase in pressure in the cooking chamber and curve N. that show the lye concentration during cooking. On average, curve P1 shows the pressure profile for thick and hard-stemmed ones, curve P2 those for thin-stemmed ones, and curve N the increase in concentration for both Str:) hard ones. Sections A, B, C and D represent the following four main working periods of the cooking process: A the preparation period for boiling, B that of boiling with water, C that of boiling with lye and D that of emptying the cooker.

Cooking can be carried out using the device according to Fig. 7 within the four working periods listed above as follows: Period A: Cooker 52 is charged with crushed food to about 9/10 parts, then closed. Valves 53 and 5 [are then opened and the air is expelled from the cooker through pipeline 57 through pipeline 55, 56 supplied with steam. Thereafter, valve 53 is blocked and the supply of steam through pipeline 55-56 is continued until a pressure (overpressure) of 0.3 to 0.5 atm in the cooker. arises. Now valve 54 is also blocked, but valve 58 is opened at the same time and the food to be cooked is fed through pipe 59-6o and shower 61 with so much hot water (ioo to io5'C) that all of the items in the cooker and pipes 59 and 6o are then fed The amount of water (cooking liquid) weighs approximately seven to eight times the dry substance of the food.

Period B: After closing valve 58, valve 62 is opened, the cooking liquid (water) is circulated with steam jet pump 63 through pipeline 56, 6o, shower 51 and the food to be cooked, and this is done for about 13 / -t to 2 hours cooked, after which the circulation is stopped by closing the valve 62 and the weakly acidic solution of extractive substances resulting from the boiling is removed from the cooker under pressure through opening valves 58 and 64 through pipeline 65 such that the liquid flowing away from below is simultaneously removed from above through pipeline 59-6o hot water supplied to the cooker (i27 to 132 ° C) is displaced.

Period C: After closing valves 6 ¢ and 58, valve 62 is opened, the new cooking liquid, as stated above, put into circulation and at the same time Time by opening the valve 66 the supply of highly concentrated sodium hydroxide solution started from container 67. With circulation of the liquid and with simultaneous Lye supply will stop after about 31/2 to ¢ hours by closing the boil Valves 66, 68 and 62 set.

Period D: Valves 58 and 6 ¢ are opened by boiling Caustic solution of extractive substances formed with lye is mixed with plenty of water through pipe 59-6o, and thereby with rinsing and cooling of the food in Connection removed from the cooker by pipe 65. Meanwhile, the steam blown off through pipe 57 and then finished after closing the valves cooked good, d. H. the digested pulp from the digester through the lower one opening of the same removed in the usual way.

Because during the P @ eriod - nB and C the heat necessary for cooking through that supplied to the cooker by the steam jet pump 63 Steam is delivered. so will the rise in pressure (temperature) in the cooking space 6 achieved by regulating the steam supply with valve 68. The increase in the alkali concentration according to Fig. 6 is similar the corresponding regulation of the lye supply with the valve 66 is effected.

The cooker is to be provided with a sieve bottom in the usual way so that from the cooker filled with food to be cooked the pipes 56 and 65 are only pure liquid can flow out.

Boiling with water doesn't just add a sizeable portion the extractive substances, but also the acidity of the food before cooking removed with lye, so the finished cooking of the food can be done with smaller lye concentrations and accordingly can be done with less lye consumption than with the usual procedures.

By increasing the pressure and the alkali concentration during cooking according to Fig. 6 achieves that each of the at different temperatures and alkaline concentrations of soluble extractive substances (intercellular substances and incrustations) dissolves at the appropriate temperature and alkali concentration, whereby : a further saving of heat and lye is achieved.

A third advantage is that the hydration of the inferior Cell types at the relatively low mean cooking temperature (pressure and Caustic concentration is so low that, even if these cell types are in significant Amount can be brought into the paper, the same is not parchment-like becomes transparent.

In a further embodiment of the invention, the described cooking made in several cookers, the cookers being connected to one another in such a way that that the cooking liquid from one cooker to be cooked in any other cooker or can be passed on to the chaff filling. Cooking happens in the sense of the countercurrent principle in such a way that the still unused pure water or the same lye: on one that has already been cooked several times with the same liquid Food left to be cooked, then from here into a food containing once less cooked food other cooker is directed us, # v., until finally the one released from the food Aqueous (acidic) or caustic solution containing ever larger amounts of substance Food that has not been boiled with water or lye comes and from here to what is done Cooking is drained. This process, known per se, is within the meaning of the invention designed so that the liquid used for cooking in the specified Sequence-even during the cooking: en flows through the cooker, whereby this flow the liquid is partly maintained by the fact that in the flow direction Maintain gradually lower pressure in successive individual digesters will.

The stoves are either in a circle or in two opposite each other Rows (Fig. To) set up and connected to each other around in such a way that Cooking, no matter with which the cooker is started, then all around progressively can be continued uninterrupted.

As an example of the execution, the execution scheme is shown in Fig such a cooking process with eight cookers and with caustic soda is mentioned. Even here the time in hours is shown in the horizontal direction (on axis Z-Z), and accordingly below the axis Z-Z is the mass flow of the individual digesters and above the axis Z = Z the change in pressure and alkali concentration placed in the individual cookers during the process.

The double lines I, II to VIII designate the eight cookers on the left, while the various arrow lines after the designations on the right-hand side of the drawing mean the following: the cooker is being charged with food by iben; steam supplied below; Let the air leave the top of the cooker: Hz the cooker is fed with hot water from above; The weakly acidic solution of extractive substances produced by boiling with water is drained from the cooker; HNz the stove is charged with fresh, hot caustic soda; N / A. by boiling with caustic soda, the caustic solution of extractive substances is removed from the bottom of the cooker; For the purpose of rinsing and cooling the finished cooked food, cold water is added to the boil from above; Aa the weakly liquefied waste water resulting from the rinsing of the finished cooked goods is drained from the cooker; Ftc the finished cooked product is removed from the cooker; The weakly acidic solution of extractive substances produced by boiling with water flows from one digester into the other; The caustic solution of extractive substances produced by boiling with caustic soda flows from one cooker into the other.

The brackets belonging to the individual arrow lines mean that the process indicated by the arrow line during those corresponding to the bracket is in progress for the entire duration.

Above the axis ZZ, PI, PII ... PVIII show the increase in pressure and curves NI, NII ... NVIII show the alkali concentration in the individual digesters during the cake, similar to that in Fig.6. individual cookers in the same four periods as when cooking in a single cooker (see A, B, C, D in Fig. 6). In Fig. 8 these periods are marked for cookers I and V (AI, BI, CI, Dl and AV, BV, CV, DV).

Fig.9 shows the equipment of the individual cookers and the pipe connections between two cookers I and II of the cooker row.

The cookers are connected to one another by pipeline 7 i in such a way that, if valves 75 and 7 6 are open and all other valves are closed, the cooking liquid from cooker I flows over into cooker II through pipelines 69-74 (arrow lines Ss and Ns in Fig. 8 ). The pressure difference between the two digesters according to fig.8 or is maintained during this Ström @ ens according to need by either appropriately selected throttling of the pressure through valves 75 and 76 through corresponding controlled steam supply through steam ejector 77th

Through pipeline 7 8 hot and cold water is supplied to the individual cookers supplied (arrow lines Hz and Wz in Fig. 8). Also the supply of unused hotter Sodium hydroxide solution (HNz in Fig. 8) is produced in such a way that the pipeline 78 incoming hot water from tank 79 through pipe 8o highly concentrated Sodium hydroxide solution is added.

Both during this supply of fresh sodium hydroxide solution and during the flow of caustic solution of extractive substances from one digester into the other the increase in the lye concentration in the individual digesters according to Fig. 8 ' by. Appropriate regulation of the lye supply from the container belonging to the cooker 79 caused by valves 8 t.

The air is passed through valves prior to the start of cooking # (in period A) 82 from the cookers already loaded with high quality by means of the pipeline 83 supplied steam expelled, while pipes 85 here only for blowing off of steam after completion of the cake in period D serve. The latter can go through a collecting pipe 86 and an intermediate expansion tank with pipes 83 are connected, so that in this way for venting and heating the with fresh Stoves that have been loaded and that use the exhaust steam from emptying stoves can be.

Drain pipe 87 serves to remove the solutions of extractive substances and the caustic waste water from the rinsing (arrow lines Sa, Na and Aa in Fig. 8).

Valves 88 remain under normal circumstances throughout the cake closed.

Fig. 10 shows the arrangement of eight giggles 1, 11 ... VIII in two rows. As can be seen, connecting pipeline 71 (section 9) is designed as a ring line in such a way that regardless of which cooker, the operation can be switched off by shutting off the associated drainage and supply valves 75 and 76 and opening the likewise associated intermediate valve 89, without this thereby affecting operation would have to be disturbed.

This embodiment of the invention can achieve a further reduction the heat and lye consumption can be achieved by on the one hand the water requirement of the cake is significantly smaller than that of the cake in a single cooker, on the other hand, both the drained caustic solution and the caustic waste water of the Rinsing only a little free, d. H. Contains unused lye. Another advantage consists in that: the discharged two kinds of solutions of extractive substances solutions of the greatest concentration attainable by boiling with water and then with lye without interrupting the cooking and pressing the food Winding or a similar operation would have to be subjected to the extractive substances by sealing these of their solutions in the form of artificial fodder, vegetable glue etc. as a by-product of paper production.

The digested pulp removed from the digester becomes with Water washed further in the usual way.

Both the grave and the fine grinding of the digested pulp happens by means of wood, rubber (rubber eIasticum), horn, leather o. The like. softer, but tough and elastic material made by grinding tools whose application is achieved that cla, i stuff, its valuable elements the mostly relatively thin bast fibers (librifirm cells) are, even between tightly set grinding tools, with effective grinding is not ground to death. Under. Milling tools are the roller and basic mill knives the Dutchman, as well as the grooved work surfaces or those on the work surfaces attached knife of the common disc, cylinder or cone mills (grinding passages, Understanding refiner.

In order to prevent the unnecessary loss of substance, the must in the course Drainage and draining operations to be used when processing the material into paper and so also when scooping the paper generally denser (higher numbered) Sieve cloths and draining pads than when producing paper from rag or wood be used.

In the context of the invention, a further reduction in the loss of substance can be achieved be achieved by the fact that it still contains significant amounts of usable pulp Waste water from washing, milling, catching sand, knots and cats, and bleaching and draining used repeatedly for the same operation on fresh fabric in such a way that, as a result of repeated use in the water, it becomes chemically detectable accumulated alkali or acid before the new application in a for the Quality of the paper to be produced is neutralized harmlessly. This repeated Application of the wastewater can only be continued until it is in the water low-quality waste that accumulates and that resulting from neutralization Salts do not adversely affect the quality of the paper to be produced.

In accordance with this principle, the caustic waste water from the first wash is also used and coarse grinding to make the lye for the rest of the processing the digested pulp to paper by known methods and with the used to cook new chopped wood. facilities.

Claims (5)

PATENT CLAIMS: i. A process for the production of paper from strohar, strength materials, characterized in that the squashed to be processed strohar_ige raw material first by pressure, bending and torsional stress then is crushed into chaff, whereupon the chaff in the moist state by application of heat to an accelerated natural pickling subjected, then the acidified chaff is boiled in a closed room at a temperature exceeding 100 ° C first with water and then with excess lye in such a way that the temperature (pressure) in the cooking space in both cooking processes and the concentration of the lye during the cooking with lye whole boiling is increased, then the pulp thus digested between wood, rubber, horn or similar soft, but tough and elastic - material made grinding tools ground (shredded) and from the material obtained in this way paper is produced in a known manner. 2. Method according to claim i, characterized in that the caloric acceleration of the acidification Waste heat from the exhaust steam or condensation water from the company is used. 3. Procedure according to claim i, characterized in that the acidified chop at the same time is cooked in several communicating cookers in such a way that the for Cooking liquid used during cooking through the chained row of cookers or flows through the food to be cooked in the same, where in the: in the flow direction successive individual cookers gradually lower pressure (temperature) is maintained. 4 .. Method according to claims i to 3, characterized in that that in the course of the processing of the digested pulp into paper the wastewater washing, grinding, sorting and bleaching the fabric repeatedly The same operation is needed on a new material, with the repeated several times in the course of the operation During use, the alkali or acid that has accumulated in the water is temporarily neutralized. 5. The method according to claims i to ¢, characterized in that the. Lye-containing wastewater from the first washing and grinding for the preparation of the lye is used for cooking new chaff.