DE933C - Process for the preparation of paper pulp from wood by chemical means - Google Patents

Description

1877.

Class 55.

ALBERT UNGERER in PFORZHEIM. Process for the preparation of paper pulp from wood by chemical means.

Patented in the German Empire on July 13, 1877. Longest duration: April 17, 1887.

The invention consists of:

1. In a new and peculiar method of isolating the cells of plants, without harming their integrity, and in order to completely rid them of those substances which are known as incrusting substances, whereby they also become important ones Parts are discolored.

2. In the use of a specially designed apparatus suitable for the purposes mentioned, to make paper stuff out of wood.

Although my method can be applied to the cells of plants in general to isolate it as one needs it for different purposes, so I consider it especially useful to make a stuff for paper production from wood or from plants, which for Nature of wood belong to, and I will therefore describe myself in the following description to the special explanation of a process and apparatus that are used for the preparation of the paper stuff made of wood are suitable.

But it will be seen that the same procedure and a similar apparatus are used for the serves more general purpose, as said above, with such detail changes as any who is practically familiar with such branches of manufacture can easily be found.

Therefore, whenever I use the words wood and stuff in the following, I fall asleep one that also the other plants, whose cells are to be isolated for other purposes, likewise are understood by this.

The main peculiarities of my process are as follows:

I bring the wood after cutting it into small pieces beforehand (I draw propose to chop it up in the form of rasped colored wood, but there is no particular one here Peculiarity of my procedure), in closed containers, in which I put it under a gradually increasing pressure and at a temperature which corresponds to this pressure, treat with caustic soda, which I renew several times and before Use heat.

In the same containers, the fabric is also washed after it has been treated as previously mentioned became.

In this way wood and other vegetable matter are freed from their incrusting substances freed and the connection of the cells broken. My method relies on that Discovery which I have made, namely, that there are some substances contained in wood and which at the beginning of the action at a comparatively low temperature are dissolved at a higher temperature than insoluble matter of humus-like Stock again knock down. This causes me to hit the wood with a previously heated To act at a gradually increased temperature. Through the constant When the lye is changed, those substances that are dissolved are carried away by the lye even before the excretion of humus-like substances can take place, as a result of the increase in temperature; this makes it even on the wood. worked in and partially decolorized, so that it is suitable for the manufacture of the best types of paper. I think that is the wood the more the lye is changed, the more evenly it is dissolved and discolored and bleached, and that's why it is. a special advantage of the apparatus described later is that it has a constant change of lye takes place. The · pressure, the duration of the action and the Concentration of the lye must be according to the particular type of wood and the degree of regulate intended discoloration. For hardwood it is sufficient to only use lye, which 3 to 4 pct. Contains anhydrous caustic sodium hydrate, the pressure is on at least 3 to 4 atmospheres and exposure has to take place for at least 5 to 6 hours.

Softwoods need the same time, a pressure of 6 atmospheres and a lye, which 5 to 6 pCt. Contains anhydrous caustic sodium hydrate. Between certain Limits can be an increase in the pressure or an increase in the duration of the action or higher concentration of the lye represent two of these conditions. The above Numbers therefore do not have to be strictly adhered to when working in practice.

Freshly cut wood is easier to work with than old wood. My procedure will

more understandable through a description of the device I use and which one the condition that a beautiful, uniform piece of paper made of wood with as little display as possible to manufacture, highly enabled.

It consists of a greater or lesser number of closed containers capable of holding the necessary To withstand pressure and chemical effects and therefore best made of iron, which containers communicate with one another in such a way that the fluids from one container to the others pour in, in order to be able to pass the whole row of vessels in this way, either downwards or upwards under controllable temperature conditions or pressure, and to finally be drained. The size and composition of the apparatus depends on the one hand on the quantity and type of wood to be used, on the other hand on the special type of material that you want to represent.

If you take hardwood as a raw material and want to make unbleached fabric from it, so you need fewer containers than to work with softwood on bleached stuff.

A number of nine containers, arranged from A to J, as shown in the accompanying drawing, is sufficient in almost every case.

Each container is surrounded by a poor conductor of heat, e.g. B. ash or sawdust, or is provided some other means of maintaining its contents at the correct temperature. Even it is provided with a separate grate to prevent accidental cooling. Further are a manhole, safety valves, steam gauges, water level gauges and other common ones Mounted equipment, as well as a special pipe system for the introduction of water and Lye in each container individually and from one container to the other.

Another important part of the apparatus is a boiler, hereinafter referred to as the caustic boiler denotes, which is provided with a furnace to heat the soda lye and to bring them to the necessary pressure, as well as a feed pump with an air chamber to to fill the containers with the necessary cold water. I give a description below about the way in which the apparatus mentioned above is used. It is of course allowed, the manipulation according to special circumstances in matters of minor Change importance.

First all containers are filled with chopped wood, then the communication between the caustic pot and the first container in A is opened, and the latter is filled with hot caustic, as well as the five following ones with caustic, which from one to the other, one after the other through the tubes which are attached for this purpose. Naturally, the pressure in each subsequent container will be lower; the-Ib. should be regulated in such a way that the liquor flows into the first container at a pressure of 6 atmospheres, but is only under a pressure of _{1/2 to 1/2} atmospheres in the sixth container. When all six containers A to F are filled with lye, the drain cock in F is opened and as much lye is drained off again as would fill one container; it goes to a recovery apparatus, where it is evaporated to dryness, calcined, and made into caustic sodium hydrate again will.

At the same time the liquid contents of the first five containers are pushed forward by cold water from the air chamber of the pump, which air chamber communicates with each of the containers A to J through pipes and taps. The pressure in this air chamber is strong enough to force the cold water into container A , and to push the liquid forward, so that at last A is filled with water and B to F with lye; each container now contains the liquor that was in the previous one. If one now asleep from the cold water, as is the connection between A and B, and presses fresh liquor in the container B, while at the same time slept the Auslafshahn of F and opens the connection between F and G. The liquid is naturally pushed forward again, and when G is filled, the inflow of fresh lye to B is prevented.

In this way, container A is now filled with water and B to G with lye.

Now the connection between A and B is opened, cold water is pressed into A , and the drain tap in G is opened until a container full of lye is drained.

A is now filled with fresh water, B with the water that passed through kettle A , C with the lye that was in B just before, etc.

Now the drain cock of G and the connection between B and C is closed, but the one between G and H is opened and fresh lye is pressed to B , which pushes the liquid contents of the next container forward until H is also filled. You now open the tap between B and C _1, a container full of lye is drained from H and cold water is pressed into A for the third time at the same time.

A, B and C are now full of water, D and H full of lye. You now sleep between C and D and the outlets at H. H and J are connected, fresh lye is pressed into D until J is full. The liquid part of A, which now had water three times, is drained off (this can be accelerated by suction or pressure), and the solid content, namely the wood, which has been thoroughly opened up and washed, is taken out. A is now filled with fresh wood and is lined up as a container to J by connecting the tubes, as the drawing explains in more detail.

The water in C, which is now through three

The container is passed, is no longer used for washing and is not pushed from C to D , but drained while fresh water is pushed to B.

The liquid that runs off from C is weak alkali and can be reused to make fresh alkali or in other ways. When C is filled with the cold water from B and B with fresh water, C and D are connected, more cold water is pressed to B and a container of lye is drained to J , so that B, C and D are now full of water, E. until J full of lye. Now, fresh liquor E is completed between D and E, established between J and the now filled with fresh wood A compound pressed until E, F, G, H, J and A are full. The fabric in B, which has been freshly watered three times, is ready, it is taken out (after the water has been drained) and B is filled with wood again.

It continues in this way without interruption. There are five to six containers inside full of lye, two or three full of water, one either occasionally emptied or with fresh wood filled. If the operation is in the right course, it will be seen that every container is always in use full of chopped up wood receives five containers full of lye which has already passed through wood and a container full of fresh suds, and then three containers full of water, the first two of which have been used for washing beforehand. The pressure is always increasing in every container, if you count backwards from the last filled container, and you get its highest grade in the container first filled with lye, at the moment when fresh lye is removed from the Caustic pot is pressed in.

If you first fill a container filled with fresh wood with lye, it should flow in from below to prevent wrong ways, but if the container is full and closed, you have to turn the tap the other way and the later fillings have to come from above go down. The waste and tributary stream is so regulated, is a quantity DAF liquor used for each container full of wood, which just covered the timber which corresponds approximately to the 2 '/ ₂ to 3 times the weight of the wood. The wood should be exposed to the lye for a total of six to seven hours; an exact time cannot be specified, as the treatment depends on the nature of the wood. The lye, which has passed through five or six containers, is boiled down, the residue is calcined, dissolved in water, and used to prepare caustic sodium hydrate. The water which has passed through three containers can be used as a weak liquor, either for bleaching or for the preparation of fresh liquor.

The caustic kettle, in which the caustic soda lye is kept ready, and which is indicated in the drawing, is constantly fed with fresh lye, and its contents are heated under the necessary pressure and directed into the containers under its own pressure. The water for washing is not heated, but is pressed cold in an air chamber and from there into the containers A to /. As it passes through two vessels before it comes into contact with hot lye, it is heated beforehand to a certain degree; at the same time the stuff is also cooled, which is of great importance because it speeds up the whole procedure.

When the third water has run off from the mass, it becomes one with water Dutch brought and beaten in it to separate the fibers of the wood, which however almost fall apart by itself, and it's the mass that way in proper wooden stuff transformed. Very little force is needed for this operation, because the mass is not ground, but only needs to be beaten and ground up.

The wood is now discolored to a considerable degree, and can be used for many purposes be used without bleaching, but if you want it to be completely white, you have to remove the last remnants of the paint. This can be done by ordinary bleaching process; most of these are applicable to my woodwork, as well as paperwork, which prepared in a different way and from different materials. But the method which I have found the economist is the following:

The stuff is treated with a solution of bleach powder or with bleach liquid, whichever three to four parts by weight of commercial bleaching powder (a little more or less) per hundred Contains parts by weight of dry stuff.

This can be done in vats or containers of ordinary construction, or in my displacement apparatus, where the bleaching liquid is pushed or pumped to and from Container to container runs.

These containers are open at the top and are best built from bricks with cement or made of wood that has been soaked with paraffin.

The purpose of this operation is less to bleach the fabric directly than to the dye by oxidation to make it soluble, after which it can be easily removed by treatment with hot caustic lye or removed even by dissolution of carbonate of sodium hydrate and subsequent leaching will.

For this purpose there is only a weak lye and a very short treatment time necessary so that this operation is very simple and not an individual discussion needs.

When working with large masses, it would be advisable to use an apparatus which is roughly constructed like that described for the first treatment and the one from

fewer containers, but in most cases this is not necessary.

After this treatment one can still bleach completely white, just as with rags, _1/2 to 1/2 pct. Bleaching powder on one hundred parts of dry stuff is in most cases sufficient for the final operation.

I lay claim to complete novelty of the method and apparatus described above, to cook, leach and wash fibrous materials continuously, especially suitable for converting wood into partially discolored wood pulp.

It is well known to me that paper stock has already been made of wood by chemical means was, but this was presented in a very costly way; one always only worked with a kettle and a lye, with a high temperature and pressure, the latter was a great obstacle to the safety of work. The consequence of this was that some substances which had dissolved at a lower temperature, reappeared at a higher temperature than Separate humus-like substances of brown color, so that the product can only be obtained by a large one Expenditure of chemicals could be bleached.

This harmful circumstance is indicated by "my Process avoided entirely as I am working with a number of containers, each of which exposed to different alkalis, the temperature of which is constantly increasing, and where each alkaline is removes with it those substances which it has dissolved before a higher temperature increases them transformed into humus-like substances.

Another recommendation of my apparatus is that it should be used to add large quantities of wood uninterrupted work in the smallest space and with the least possible effort of Can process chemicals,

My process and apparatus can also be used for the preparation of paper stock from wood, for ■ dismantling of all vegetable matter are needed in their individual cells, and by one Modifications necessary for each case, adapted to the nature of the plant, can be introduced Obtained staple fibers, which since then have not been used with advantage for this purpose especially because in my procedure the cells got their natural size and Maintained shape and changed neither chemically nor in any other way, but completely be freed from their incrustations. .

For this purpose I sheet drawings.