EP1351993A1

EP1351993A1 - Device and method for the continuous synthesis of cellulose carbamate

Info

Publication number: EP1351993A1
Application number: EP02718029A
Authority: EP
Inventors: Joachim Seelig; Rudolf KÄMPF; Reinhard Wolf
Original assignee: ZiAG Plant Engineering GmbH
Current assignee: LL Plant Engineering AG
Priority date: 2001-01-18
Filing date: 2002-01-16
Publication date: 2003-10-15
Also published as: WO2002060956A1; DE10102172A1

Abstract

The invention relates to a method for the synthesis of cellulose carbamate and a transport device (1) for transporting a cellulose slurry (4) dissolved in an organic reaction carrier. Until now, series of stirred-tank reactors were used for the synthesis of cellulose carbamate. Said series of stirred-tank reactors are complex and cause irregularities in the quality of the cellulose carbamate due to a wide range of retention time of the cellulose slurry in the series of stirred-tank reactors. According to the invention, a transport device (1) is used as a reactor system to carry out the continuous synthesis of cellulose carbamate or to enable said synthesis to be carried out. To this end, a cellulose slurry (4) suspended in an inert organic reaction carrier is heated in the continuous transport device (1) by means of a heating device (25, 26, 27), and is maintained essentially at the reaction temperature when transported in the transport device (1) along a transport track (5).

Description

Device and method for the continuous synthesis of cellulose carbamate

The invention relates to a conveying device for conveying a cellulose slurry dissolved in an organic reaction carrier, in which a synthesis of cellulose carbamate takes place, and a method for the synthesis of cellulose carbamate.

Cellulose carbamate is currently synthesized from a cellulose slurry in stirred tank cascades in accordance with the process described in DE 42 42 437 C2 and DE 44 17 140 C2.

The currently known processes use the process steps described in DE 42 42 437 C2 and DE 44 17 140 C2 for the conversion of cellulose with urea to cellulose carbamate:

The cellulose delivered in plates is swollen and activated in a dipping press or other device in 10% to 25% sodium hydroxide solution for several hours. After this phase, the excess liquor is pressed off, compressing to a ratio of 2: 1 to 3: 1. This material then gets into a shredder and is broken up into small pieces, on which the molecular chain length is shortened either statically in a traveling grate apparatus or dynamically in a rotary tube in a decomposition process that takes several hours and takes place at elevated temperatures.

After this so-called ripening process, the speed of which depends on the temperature and the alkali concentration, the breakdown products together with the alkali lye are washed out in a multi-stage process. Since not all of the alkali is removed in the pores by physisorption and in the crystal lattice spaces by chemisorption, neutralization follows, which is usually done with acetic acid and less frequently with CO ₂ . This material is washed again to remove any neutralization products still adhering to it. After the residual liquor has been pressed off, the comminuted material is conveyed into a stirred tank in the process of DE 44 17 140 C2, which can also be replaced by a plurality of stirred tanks connected in series. The cellulose is mixed with 50 ° C, aqueous urea solution in a concentration of 40% by mass. The agitated, urea-containing cellulose suspension passes through a screw press, in which the excess urea solution is pressed, into a comminution and loosening apparatus, in which the preheated liquid organic reaction medium is also added. This mixture passes into a first evaporator operated under excess pressure, in which part of the water and part of the organic reaction medium are evaporated off overhead, while the residual water is removed in a second evaporator operating under reduced pressure.

From the last evaporator, the suspension consisting of cellulose and urea in the reaction carrier passes through a heat exchanger, in which it is brought to the reaction temperature, into a cascade of stirred tanks. The reaction takes place at the temperature of the boiling reaction support and at residence times in the individual vessels, which are determined on the one hand by the boiling point of the reaction support and on the other hand by the individual size of the stirred tank volume.

The mixture is drawn off from the last stirring vessel through an outlet line, cooled in a heat exchanger and then reaches a rotary drum pressure filter on which the reaction carrier is filtered off and returns to the reaction circuit.

The filter cake consisting of cellulose carbamate, excess urea and adhering reaction carrier is washed with alcohol and water in the process of DE 44 17 140 C2. An additional step with suspending the filter cake and filtering is mentioned as expedient. The washed, moist cellulose carbamate is removed from the rotary pressure filter and sent for drying or direct processing. The carbamate is largely freed from the heat exchanger by decanting and filtering. The outflowing first washing filter Rat, which consists of reaction support, alcohol and part of the excess urea, is combined with the second washing filtrate and fed to an extraction column into which so much water is fed that a separation in the reaction support phase and into a urea-containing alcoholic aqueous phase takes place.

Low urea water originating from the bottom of an ammonia stripper is preferably fed into the extraction together with fresh water. The urea-containing alcoholic aqueous phase is fed to a rectification column in which the methanol or ethanol is driven off overhead. The alcohol is sent for in-process recycling. The aqueous urea solution flowing off at the bottom of the rectification column returns to the circuit of the urea solution.

The boiling reaction medium in the reaction vessels expels the ammonia formed during the formation of carbamate from the reaction mixture and flows through the condenser together with the vapors. The major part of the reaction carrier vapor is condensed there and the condensate is returned to the first reaction vessel. The vapors passing through the condenser, which essentially consist of ammonia, carbon dioxide and reaction carrier, are washed in a scrubber with a circulated, cooled aqueous solution. The washing liquid removed from the circuit is separated in a separation vessel and the organic reaction carrier is returned directly to the process. In the ammonia stripper, water, ammonia and residual amounts of reaction carrier vapor are stripped off overhead and sent for disposal, while the sump, which is loaded with only little urea, is used in the extraction of the washing filtrates.

In the process of DE 42 42 437 C2, instead of washing with alcohol to remove the reaction support and washing with water to displace and remove the alcohol from the cellulose carbamate matrix, an azeotropic distillation is carried out. There, the cellulose carbamate containing the reaction medium is only pressed out in the rotary drum pressure filter and, with the remaining proportions of urea and reaction medium, remains in a mixing tank in which it is mixed with water is suspended. This suspension then comes into the evaporator. In it, a mixture of reaction carrier vapor and water vapor is drawn off overhead from the suspension until all of the reaction carrier bound in the carbamate has been removed from the mixture.

The vapor mixture is deposited in the condenser and separated into two phases in the separation vessel. The organic, light phase goes back into the reaction medium circuit, while the aqueous condensate is fed into the washing circuit around the scrubber. The outlet from the evaporator consists of cellulose carbamate and urea and goes into a relaxation pot, in which it cools down strongly by evaporative cooling. The water vapor is condensed and used as wash water on a filter. The wet product passes onto a belt filter, in which a concentrated urea solution is drawn off in the first zone and the carbamate is washed free of urea in the subsequent countercurrent washing stages using fresh water. The wash water and the concentrated urea solution are combined and go into the circulation of the urea solution. The moist cellulose carbamate, which is free of urea, leaves the plant and is either dried or directly dissolved for further processing.

The main disadvantage of the stirred kettle cascade, as used in the processes of DE 42 42 437 C2 and DE 44 17 140 C2, is that the cellulose dwell time in the stirred kettle cascade shows considerable variations. The scatter increases with the number of stages in the cascade of stirred tanks.

In the carbamate synthesis, this disadvantage leads to a considerable deterioration in the quality of the cellulose carbamate and also to additional losses due to the fact that unreacted or only partially converted cellulose remains and the formation of cellulose carbamate, which is already beginning to crosslink. After all, the stirred tank cascades are complex, since each stirred tank has to have its own level control and a transfer pump to the next tank.

In view of these disadvantages of the conventional stirred kettle cascade for the synthesis of cellulose carbamate, the object of the present invention is to provide a method and an apparatus with which cellulose carbamate of constant quality can be produced inexpensively without great design effort.

For the conveying device mentioned at the outset, the above-mentioned object is achieved in that the conveying device is designed as a reactor system for the continuous synthesis of cellulose carbamate and with a conveying means by means of which the dissolved cellulose slurry can be conveyed continuously along a conveying path from a feeding area to a dispensing area and with a heating device by means of which the conveyor line can be heated at least in sections.

For the method mentioned at the outset, the above-mentioned object is achieved according to the invention in that the synthesis of cellulose carbamate takes place continuously, in that a cellulose slurry suspended in an inert organic reaction medium is first heated in a continuously conveying conveying device and during conveying in the conveying device along a conveying path to im Main reaction temperature is maintained.

The process parameters and the starting materials and additives for the production of cellulose carbamate can be found in the skilled worker in DE 42 42 437 C2 and DE 44 17 140 C2, the conveying device according to the invention being used instead of the stirred cascades.

This improvement according to the invention of the conventional stirred kettle cascades and of the process for the synthesis of cellulose carbamate leads to a constant residence time of the cellulose due to the continuously conveying conveying device. loose slurries in the conveyor so that a constant quality of the cellulose carbamate is achieved. By designing the reaction system as a conveying device, the elaborate stirred kettles and their associated peripheral devices can be dispensed with, since the synthesis of cellulose carbamate now takes place while the cellulose slurry is being conveyed.

The solution according to the invention is thus structurally simpler and overall less expensive than the conventional stirred tank cascades.

In order to enable the synthesis of cellulose carbamate during transport through the conveyor, the conveyor is provided with a heating device according to the invention, so that while the dissolved cellulose slurry is conveyed along the conveyor line, the cellulose slurry is kept at the reaction temperature or at the boil and the cellulose carrbamate can be synthesized ,

In a particularly advantageous further development of the method or of the reaction system designed as a conveyor, the reaction carrier remains permanently in the conveyor. This can happen, for example, in that excess reaction carriers are derived from the conveyor device or from the conveyor section, processed again and fed back to the conveyor device. This principle makes it possible to save heating energy, since the reaction carrier can always be kept at almost the same temperature and does not have to be constantly re-heated.

A further advantage of this principle is that only a small part of the reaction carrier remaining in the conveying device has to be discharged for processing, in particular for cleaning, since practically only intercalated cellulose is introduced and cellulose carbamate is discharged.

In order to shorten the heating section in the conveying device or the reactor system and thus to reduce the dwell time of the cellulose slurry in the conveying device, it can be provided in a further advantageous embodiment that the reaction carrier heated at the beginning of the conveying section, its temperature is at least in the range of the reaction temperature to which cellulose slurry is fed. A particularly efficient heating is possible if, in a further advantageous embodiment, the reaction carrier fed in at the beginning of the conveyor line is blown into the conveyor line in vapor form. The reaction carrier can also be slightly overheated. With this configuration, very rapid heating to the reaction temperature is possible. For blowing in the steam, at least one corresponding nozzle can be provided in the conveying path of the conveying device, preferably at the bottom of the conveying path.

The heating and evaporation of the reaction carrier can be carried out in a particularly energy-saving manner if, in a further advantageous embodiment, the reaction carrier fed in at the beginning of the conveying path was previously derived from the conveying device or from the conveying path in accordance with the principle set out above. In this case, only a slight reheating of the reaction carrier is necessary.

In a further advantageous embodiment it can be provided that the conveying device can be rinsed with a detergent. Cellulose or cellulose carbamate remaining in the conveying device or in the conveying section is to be rinsed off by the detergent. The rinsing with the detergent can take place intermittently in a further embodiment. Reaction carrier which has previously been derived from the conveyor, for example, can be used as the detergent.

In normal operation, the conveyor line will not be completely filled with reaction carriers and cellulose slurry, but will have an adjustable fill level. In the following, the area of the conveyor line filled with suspended cellulose slurry is referred to as the reaction space. In this reaction space, cellulose slurry can be continuously rinsed from the conveyor by the rinsing agent during operation of the conveyor.

A so-called vapor space is formed above the reaction space, in which vapor vapor collects. In a further advantageous embodiment, this vapor can be discharged from the conveying device and a vapor condenser gate be forwarded. In order to allow the process for the synthesis of cellulose carbamate to run in an energy-efficient, closed system as possible, the vapor condensate generated from the vapor vapor in the vapor condenser can be mixed with reaction carrier, in particular with reaction carrier derived from the conveying device, and fed back to the method for cellulose carbamate synthesis.

The principle of a closed reactor and conveyor system, in which the reaction carrier circulates with as little loss as possible and with only a few temperature differences, is improved in that, in a further advantageous embodiment, the cellulose slurry enters the conveyor device or the reactor system essentially without reaction carriers and - in another Design - can be removed from the conveyor essentially without reaction carriers.

This can be achieved, for example, by the cellulose slurry being transported to a feed area by means of a screen belt. When transported on the sieve belt, the cellulose slurry is essentially freed from the reaction carrier.

Regardless of this, in a further embodiment, the cellulose slurry in a delivery area of the conveying device can be removed from the conveying device by means of a discharge device in such a way that the reaction medium remains essentially in the delivery area during transport with the discharge device.

To set the filling level within the conveyor, an overflow can be provided at one or both ends of the conveyor line. The reaction carrier flowing out of the overflow can be returned to the conveyor device or the conveyor line in accordance with the above principle.

In particular, the conveying device can be designed as a screw conveyor and the conveying means can be essentially helical, for example as a conveying screw. To ensure the best possible heating or temperature stability within the To reach the conveyor line, it is advantageous if the largest possible surface that comes into contact with the cellulose slurry is heated in the conveyor line.

The measures on which the invention is based are not limited to screw conveyors. Instead of a screw conveyor, trough or scraper chain conveyors can also be used. On the one hand, it is important that the conveyor is closed, so that the reaction carrier can circulate with as little loss as possible.

On the other hand, it is important to keep the edge as small as possible, which allows only a slight backmixing. In this way, a uniform residence time of the cellulose slurry in the conveyor can be achieved.

This can happen, for example, in that the conveying means itself is heated, or in that a jacket surrounding the conveying path, at least in sections, is heated.

The invention is explained in more detail below on the basis of exemplary embodiments with reference to the drawings.

Show it:

Figure 1 shows a first embodiment of a conveyor device according to the invention, by which a method for the continuous synthesis of cellulose carbamate can be carried out.

Fig. 2 is a section along the line II-II of Fig. 1;

3 shows a second exemplary embodiment of a conveyor device according to the invention, by means of which a method for the continuous synthesis of cellulose carbamate can be carried out;

4 shows a section along the line IV-IV of FIG. 3rd In Fig. 1, the structure of a reactor system for the synthesis of cellulose carbamate formed conveyor 1 is shown schematically. The conveyor 1 is a continuous conveyor and has a conveyor 2, which is designed as a screw in the embodiment of FIG. 1. The screw 2 is driven in rotation by a motor 3 and, when rotating, conveys a cellulose slurry 4 slurried in an organic reaction carrier continuously along a conveyor path 5.

It should be noted that in the following only a helical conveyor 2 will be discussed as an example. As the person skilled in the art recognizes, a scraper chain conveyor or a trough conveyor can also be used instead of the screw 2. The rest of the conveyor can remain largely unchanged.

The conveyor section 5 extends from a feed area 6 at the beginning of the conveyor section, where the cellulose slurry is introduced into the conveyor device 1 designed as a reactor system, to a discharge area 7 at the end of the conveyor section 5, from where the cellulose slurry or the cellulose carbamate is discharged from the conveyor device 1 becomes.

In the exemplary embodiment in FIG. 1, the cellulose slurry can be supplied to the application area 6 essentially free of reaction carriers or together with reaction carriers via a feed line 8. The feed area 6 is equipped with an adjustable overflow weir 9, by means of which the fill level 10 of the dissolved cellulose slurry in the conveying device 1 can be adjusted. The reaction carrier 9a running over the front weir 9 enters an overflow chamber 11, from where it is discharged via a discharge line 12 from the conveying path 5 or the conveying device.

In the discharge or discharge area 7 there is also an overflow weir 13 from which excess reaction carrier 13a flows into a rear overflow chamber 14. From the overflow chamber 14, the reaction carrier is derived from the conveyor section 5 by means of a discharge line 15. The two weirs 9, 13 are preferably always set to the same height. In the exemplary embodiment of FIG. 1, the excess reaction carrier from the front overflow chamber 9 and the rear overflow chamber 13, which was in each case derived via the discharge lines 12 and 15, is brought together in a collecting line 16 and by means of a filter and a pump, not shown in FIG. 1 17 distributed over a line 18 of a heating device 19, via a line 20 to a rinsing system 21 and via a line 22 to a cooling vessel, not shown.

The heating device 19 is designed as an evaporator or superheater and heats up the filtered reaction carrier derived from the conveyor section. From the heating device 19, the overheated reaction carrier is conducted via a line 23, preferably in vapor form, to a plurality of nozzles 25 attached to the bottom 24 of the conveying device 1. The nozzles 25 are all arranged in a front section of the conveyor section 5 facing the task area. The superheated steam is blown into the dissolved cellulose slurry through the nozzles 25 in the inlet region of the conveying section, so that it is quickly heated to the reaction temperature. The cellulose slurry is usually introduced into the feed area at a temperature of 60 ° C. to 90 ° C. and then heated by means of the steam nozzles 25 to the reaction temperature of 120 ° C. to approx. 170 ° C. via the inlet area and preferably brought to the boil , After heating, the dissolved cellulose slurry 4 is kept essentially at this reaction temperature during the transport along the conveyor path 5. The residence time of the dissolved cellulose slurry in the conveyor is approximately 40 to 120 minutes. During this time, the cellulose slurry is conveyed from the delivery area to the discharge area.

After heating, the reaction temperature of the cellulose slurry 4 is maintained by a plurality of heating devices: on the one hand, the jacket 26, which at least in sections surrounds the conveying section 5 — preferably in the region of the reaction space 4 — is essentially tubular. For this purpose, the jacket 26 can be flowed through by a heating fluid or else have electrical or otherwise operated heating elements. In addition, the conveying means, in the exemplary embodiment of FIG. 1, the screw 2 can be heated via a heating device 27. Here, too, a heating medium can flow through the screw for heating, or it can be electrically heated.

At the end of the conveyor line, the synthesized cellulose carbamate is conveyed out of the discharge area 7 by means of a discharge device 28.

The size of the reaction space 4 of the conveyor 1, in which the cellulose carbamate is synthesized, is essentially determined by the fill level 10. The filling level 10 is in turn set by the position of the overflow weirs 9 and 13 at the two ends of the conveyor. An essentially cellulose-free vapor space is formed above the reaction space, in which the vapor vapor is collected and fed to an vapor condenser 31 via vapor lines 30. In the exemplary embodiment in FIG. 1, heat is drawn from the vapor vapor in the vapor condenser 31 via a cooling line 32 and the vapor condensate is mixed with the reaction medium 18 from the overflow chambers 11 and 14 via a line 33 in the evaporator or superheater and supplied to the heating device 25. Exhaust air purification can take place via a line 34.

In the vapor space 29, the flushing device 21 is arranged, which is provided with a multiplicity of flushing nozzles 35, through which filtered reaction carriers are directed from the line 20 onto the conveying means 2. When the rinsing device 21 is in operation, cellulose slurry or cellulose carbamate, which adheres to the conveyor 2, is rinsed back into the reaction space from the upper, cellulose-free area. The flushing device 21 is preferably operated intermittently. In this way, the conveyor 2 is cleaned during the operation of the conveyor and while carbamate synthesis is in progress.

In Fig. 2 a section along the line II-II of Fig. 1 is shown schematically.

It can be seen in FIG. 2 that the heating jacket 26 essentially only surrounds the reaction space 4. The vapor space 29 has a vapor dome 36 which forms a bulge upward in relation to the casing 37 of the conveying path. This In the exemplary embodiment in FIG. 2, bulging is produced in that a tubular segment 38 is placed on the tubular jacket 37, which at least partially surrounds the conveyor section 5, the jacket of the tube 37 being omitted in the region of the tubular segment 38. The vapor lines 30 end in the vapor dome 36 and derive the vapor accumulating there from the vapor dome 36.

It can also be seen in FIG. 2 that the spray nozzles 35 are sunk in the conversion of the conveying path. The spray nozzles 35 can be arranged in the vapor dome 36 or in the vicinity of its lower edge. An arrangement in the upper part of the conveying device is preferred, so that the conveying means can be flushed out well.

FIG. 3 shows a further exemplary embodiment of the conveyor device according to the invention, which is designed as a reactor system. The embodiment of FIG. 3 has a large number of correspondences with the embodiment of FIG.

2 on. Only the differences from the exemplary embodiment in FIG. 1 are discussed below. For the same or similar elements in Figs. 1, 2 and

3 uses the same reference numerals.

A difference to the exemplary embodiment in FIG. 2 lies in a differently designed dispensing device 40: in the exemplary embodiment in FIG. 3, the feeding device 40 is designed as a screen belt 41. The cellulose slurry 42 coming from the stripping is transported on the sieve belt 41 into the feed area 6 of the conveying device 1. The cellulose slurry is separated from most of the reaction carrier during transport on the screen belt. The separated reaction carrier is passed through a line 43 for mashing.

The conveying, heating of the cellulose slurry dissolved in the reaction carrier and the reprocessing of the reaction carrier in the conveying device 1 take place in the embodiment of FIG. 3 in the same way as in the embodiment of FIG. 2. Another difference from the embodiment of FIG. 2 in the embodiment of FIG. 3 lies in the different configuration of the discharge device 28. In contrast to the embodiment of FIG. 2, the discharge device is not designed as a screw pump, but rather is designed so that it only contains the cellulose carbamate promotes the discharge area 7 and thereby leaves most of the reaction carrier in the discharge area except for the part adhering to the cellulose carbamate.

Thus, in the exemplary embodiment in FIG. 3, a more efficient recirculation of the reaction carrier in the conveyor device or the reactor system 1 is possible. This leads to an improved energy saving, since the stripped and intercalated cellulose has to be brought from the stripping temperature alone, i.e. from a temperature between 60 ° C and 90 ° C, to the reaction temperature, i.e. to a temperature between 120 ° C and 170 ° C , The hot reaction carrier remains in the reactor, so that only a small part of the stream has to be removed for cleaning, filtered, reprocessed and reheated.

The cellulose carbamate is fed from the discharge device 28 to a next process step for further processing.

4 schematically shows a section along the line IV-IV. The cross section of the exemplary embodiment of FIG. 3 largely corresponds to the cross section of the exemplary embodiment of FIG. 1 as shown in FIG. 2. Therefore, only the differences are discussed below.

In contrast to the exemplary embodiment in FIG. 2, in the exemplary embodiment in FIG. 4 no tube segment is attached, but the cross section is elliptical or oval. The arrangement of the conveying means 2 in the lower region of the conveying path 5 leaves sufficient vapor space in this configuration in the upper region of the conveying path 5. The flushing device 21 is attached in the upper part of the conveyor line. If the dimensions are large enough, the conveyor line can also be designed as a normal pipe. Only the fill level 10 has to be dimensioned such that sufficient vapor space 29 is available. In this case, the conveyor 2 can protrude into the vapor space 29. Then the nozzles 21 - like the nozzles 25 - are to be designed so that they do not collide with the conveying means. Likewise, the mouth of the vapor line 30 is then to be recessed.

The conveying device according to the invention, designed as a reaction system, conveys the cellulose slurry arriving in the feed area 6 evenly without scattering the dwell times through the conveying path 5, so that a uniform quality of the cellulose slurry is achieved. Another positive effect is achieved by the constant recirculation of part of the reaction carrier. The recirculation of the reaction carrier saves energy and material. Further devices, such as the rinsing device and a device 25 for quickly heating the cellulose slurry at the entry area of the conveyor line, represent further advantageous configurations of the conveyor device, as does the possibility of heating the conveyor means 2 and casing 26 of the conveyor line 5, at least in the area of the reaction space 4.

Claims

claims

1. Conveying device (1) for conveying a cellulose slurry dissolved in an organic reaction carrier, characterized in that the conveying device (1) is designed as a reactor system for the continuous synthesis of cellulose carbamate and with a conveying means (2) through which the dissolved cellulose slurry along a conveying path ( 5) can be conveyed continuously from a feed area (6) to a delivery area (7), and is provided with at least one heating device, by means of which the conveyor line (5) can be heated at least in sections.

2. Conveying device (1) according to claim 1, characterized in that the conveying means comprises a heating device (26, 27) which acts at least in sections on a surface of the conveying means (2) coming into contact with the suspended cellulose slurry.

3. Conveying device (1) according to claim 1 or 2, characterized in that the conveying device (1) is designed as a screw conveyor and the conveying means (2) is essentially helical.

4. Conveyor device (1) according to one of the above claims, characterized in that the conveyor section (5) is at least partially surrounded by a jacket (26) heated by a heating device.

5. Conveyor device (1) according to one of the above claims, characterized in that the conveyor section (5) is tubular at least in sections.

6. Conveying device (1) according to claim 5, characterized in that the cross section of the conveyor section (5) is at least in sections elliptical or oval.

7. Conveying device (1) according to any one of the above claims, characterized in that in the upper region of the conveyor section (5) arranged counter to the direction of gravity, there is at least one flushing device (21) through which a flushing agent for cleaning the conveying means (2) can be introduced into the conveyor line (5).

8. Conveying device (1) according to claim 7, characterized in that the flushing device has at least one spray nozzle (21) through which the flushing agent is directed towards the conveying means.

9. Conveying device (1) according to one of the above claims, characterized in that a level adjusting device (9, 13) is arranged at at least one end in the conveying direction, through which the fill level (10) of the loosened cellulose slurry at least within the conveying path (5 ) is adjustable.

10. Conveying device (1) according to claim 9, characterized in that the level adjustment device (9, 13) is designed as an overflow chamber with an adjustable overflow weir.

11. Conveying device (1) according to one of the above claims, characterized in that a heating device with at least one outlet opening (25) is arranged on the front region of the conveying path (5) in the conveying direction, through which heated reaction carriers into the conveying path (5) can be introduced.

12. Conveyor device (1) according to one of the above claims, characterized in that the conveyor device (1) is designed as a scraper chain conveyor.

13. Conveying device (1) according to one of the above claims, characterized in that the conveying device (1) is designed as a trough conveyor.

14. A process for the synthesis of cellulose carbamate, characterized in that the synthesis of cellulose carbamate is carried out continuously by first heating a cellulose slurry suspended in an inert organic reaction medium in a continuously conveying conveyor (1) and during conveying in the conveyor (1). is maintained at a substantially reaction temperature along a conveyor line (5).

15. The method according to claim 14, characterized in that the filling level of the suspended cellulose slurries conveyed in the conveying device (1) is controlled.

16. The method according to claim 14 or 15, characterized in that excess reaction carrier is derived from the conveyor (1), processed and fed back to the conveyor (1).

17. The method according to any one of claims 14 to 16, characterized in that at the beginning of the conveyor section (5) heated reaction carrier, the temperature of which is at least in the region of the reaction temperature, is fed to the cellulose slurry.

18. The method according to claim 17, characterized in that the reaction carrier supplied at the beginning of the conveyor section (5) is blown into the conveyor section (5) in vapor form.

19. The method according to any one of claims 16 to 18, characterized in that the reaction carrier, which is supplied at the beginning of the conveyor section (5), contains reaction carriers which have been derived from the conveyor device (1).

20. The method according to any one of claims 14 to 19, characterized in that the conveyor (1) is rinsed by a detergent.

21. The method according to claim 20, characterized in that reaction carrier is used as rinsing agent.

22. The method according to claim 21, characterized in that excess reaction carrier derived from the conveying device (1) is used as the rinsing agent.

23. The method according to any one of claims 14 to 22, characterized in that the cellulose slurry is removed in a delivery area (7) by means of a discharge device (28) from the conveying device (1), the reaction carrier in the transport device with the discharge device (28) remains essentially in the delivery area (7).

24. The method according to any one of claims 14 to 23, characterized in that vapor vapor is derived from the conveyor section (5) and fed to a vapor condenser (31).

25. The method according to claim 24, characterized in that the vapor condensate generated in the vapor condenser (31) is mixed with reaction carrier.

26. The method according to claim 25, characterized in that the reaction carrier derived from the conveyor section (5) is filtered and mixed with vapor condensate.

27. The method according to any one of claims 14 to 26, characterized in that the cellulose slurry in a feed area (6) of the conveyor (1) is supplied essentially free of reaction carriers.

28. The method according to claim 27, characterized in that the cellulose slurry is transported to the feed area (6) by means of a screen belt (41), wherein it is substantially freed from the reaction carrier during transport on the screen belt.