WO2004051166A2 - Combined dewatering, drying and control of particle size of solids - Google Patents

Abstract

The aim of the invention is to obtain larger granules with reduced residual moisture during the drying of sticky sludge that is difficult to dewater, with low expenditure in terms of equipment and energy. To achieve this, a centrifuge is integrated into a dryer housing of a combined dewatering and drying device, in such a way that at least the solid dropping zone of the centrifuge lies directly in the dryer housing and after multiple deflections, the moist particles of the centrifuged solid spray-mist from the centrifuge, which are spatially well distributed, collide directly with the dry particles of the surrounding circulating fluidised bed. The residence time in the spray zone of the particles that are enlarged by agglomeration granulation and are simultaneously dried is adjusted by the speed of the heating gas. The flow of the heating gas is influenced in a targeted manner by guide and impact elements that are installed in the dryer chamber, in order to cause a uniform distribution of solids and gas, to prevent dead space and to guarantee an intensive contact between the heating gas and the moist, continuously enlarging solid particles. According to the invention the mechanically pre-dewatered and finely dispersed, moist sludge particles are uniformly distributed in a continuous process in the drying gas containing solids and are thus prevented from making premature contact with the dryer walls, the fine dry particles are enlarged by agglomeration granulation and the centrifuge dryer remains free of incrustation even in the presence of sticky products, without back-mixing or pre-treating the sludge.

Description

 Combined dehumidification, drying and grain size control of solids

description

The invention relates to a method and an apparatus for producing a dried, granular or powdery material from a suspension or slurry, for. B. industrial sludges such as gypsum, fine coal, mineral sludge, organic fermenter broths, paint sludge, sewage sludge or the like, in which the continuously added suspension first in a continuously operating centrifuge such. B. solid-bowl screw centrifuge or screen screw centrifuge is mechanically dewatered, at the same time the constantly dewatered thick matter immediately and without intermediate storage and dosing and without leaving the apparatus at least one further treatment such as B. a short-term drying and / or build-up granulation of only a few seconds, then pneumatically transported to the separator and continuously discharged there. Furthermore, the invention relates to a device for carrying out such a short-term method with a solid-bowl screw centrifuge or sieve screw centrifuge for mechanical drainage inside, a dryer housing which at least partially surrounds the centrifuge, the rotating solid discharge of the centrifuge simultaneously as a metering device and atomizing machine for the pre-dewatered solid in the enveloping The dryer acts, with means for deflecting the particle trajectory in the axial direction of the centrifuge, with at least one hot gas inlet and at least one outlet for the dried solid particles and the drying gas, a pneumatic delivery line, post-drying, a separator with a discharge element for the dried material, and a blower for the promotion of gases, a gas heater, a gas cleaning station and an outlet for the exhaust gas.

A method and a device of this type are known from EP 0.591 299 and from DE 196 31 605. 7 - 09 and DE 44-07536 A 1 known.

In this known dehumidifier, the thick matter particles emerging from the centrifuge at high speed are removed by suitable means, e.g. B. deflected by baffles or by suitable gas flow in the axial direction of the centrifuge. The sprayed, pre-dewatered solid particles are washed around by the drying gas at a high relative speed and dried very quickly. The drying room is, for example, a stepped concentric annular space. It is made from the outer dryer housing, the rotating drum barrel inside the centrifuge or an inner, formed the rotating drum of the centrifuge surrounding non-rotating housing and the two housing end walls.

DE PS 12 17 983 describes a method and the device for this purpose for the heat treatment of a granular or powdery material, in which the already granular, moist material is introduced in a hot air stream, dried in a fluidized bed, ground in a fluidized bed or in a beater mill, sifted and the dried fine material is discharged, the coarser particles advantageously staying longer in the system. DE PS 39 15 082 describes a method and a system for dewatering and drying sewage sludge which consists of many individual devices connected in series with different assigned functions.

DE OS 2628 948 describes a method for dehydrating and drying fine, granular products from a suspension, which consists of a mechanical filter and a downstream rotating contact dryer.

In DE OS 33 40636 a method is shown with device for batchwise combined dewatering and drying in a plurality of series-connected apparatuses, the product must be treated in a long-term but dryer and thereby adversely verändem ^'can.

There are also a number of proposals for combined dehumidification and drying, such as, for example, in DE PS 36 30 920 or DE PS 948 497, in which a dryer is directly connected to a pusher centrifuge.

In OS DE 1 432 864 a device for the production of dry solids from solid-liquid mixtures is known which, after mechanical dewatering, the moist solid, e.g. B. sodium bisulfite, crushed with a rotating splitter before the downstream, operated with hot nitrogen current dryer. US Pat. No. 1,936,866 describes a combination of a screen centrifuge with a centrifugal dryer for dehumidifying and chemically modifying ammonium sulfate crystals. , -

DE OS 24 55 312 describes a solid-bowl screw centrifuge with a downstream device for dewatering and washing calcium sulfate hemihydrate, which is produced as a waste product with harmful impurities built into the gypsum and can therefore not be processed in conventional drying processes without a reduction in quality. In order to remove the impurities contained in waste plaster, the plaster is recrystallized from calcium sulfate-alfa hemihydrate immediately after leaving the decanter.

In the processes and devices listed, only very coarse-grained solids can be centrifuged in the sieve centrifuges mentioned and then dried become, or the number of individual apparatuses and conveyors necessary for the intended treatment is very large.

Solid-bowl screw centrifuges are successfully used to separate the liquid from fine-grained industrial products with a large specific surface area. However, the separated solid cake binds relatively large amounts of liquid from the mother liquor, which can only be removed with great effort in downstream washing and drying devices in order to obtain the solid in pure form. The separated fine-grained solid contains a high residual moisture and usually has a sticky, pasty consistency, which often leads to blockages in the downstream transport equipment and apparatus.

Due to the long periods of stay during the subsequent treatment such. B. Drying, certain substances are damaged by chemical side reactions, or the yield of desired ingredients is reduced by progressive disintegration during the long processing time, such as. B. in the extraction of active ingredients from biotechnological fermentation broths. For particularly high-quality products, such as B. certain chemical products or pharmaceuticals, the risk of contamination and product contamination is very large due to: the large number of apparatuses and conveyors used. For these extremely sensitive products, processing from start to finish in a closed, combined multifunctional device with very short treatment times and very small quantities of products that are simultaneously in the device is very advantageous in a continuous process.

These requirements, which are necessary in the case of sensitive, industrially produced fine-grained suspensions, such as the shortest treatment time, low hold-up in solids, high active substance yield rate, no contamination, encapsulation against the environment, multiple functions in a single, continuously operating apparatus, low investment costs, are currently becoming obsolete the technology is insufficiently and unsatisfactorily fulfilled.

When dehumidifying viscous lamb-like solid-liquid mixtures by mechanical dewatering in the centrifuge to a moist thick material and then drying in the outer drying room to form granules, a minimum degree of mechanical pre-dewatering in the centrifuge must be achieved so that it does not lead to undesirable incrustation of the housing in certain sludges comes. As has been shown in practice, deposits and incrustations on the deflection surfaces, in the dryer housing or in the subsequent apparatus are possible, in particular in the case of very poor mechanical preliminary dewatering through the centrifuges or in the case of very sticky and moist thick materials. This creates disruptions and business interruptions in the continuous drying operation, associated with great economic disadvantages. So far, attempts have been made to remove such difficult to drain sludges such. B. favorable by adding additives in their moisture and adhesive behavior. However, the cost of this is considerable.

Another disadvantage of fine-grained suspensions is the small size of the dried particles and their particle size distribution. The small particles with a very large specific surface area produced by the process of particle formation at the solids discharge of the centrifuge allow very short drying times, but larger granules are sometimes required for the storage and further processing of the dried product. Especially with very low residual moisture, single-grain dried sludges tend to generate dust when loading or transporting.

The invention is therefore based on the object to avoid these disadvantages and to provide a combined dehumidifier of the type mentioned, in which even with poorly dewatered thick matter, or even with very sticky sludges, no deposits and incrustations can occur in the dryer room, the effort and the costs for the entire treatment, such as mechanical dehumidification, washing, chemical conversion, expulsion of volatile components, drying, avoidance of undesirable side reactions, sanitization, increasing the yield, by means of the short-term treatment in a continuously working multifunction apparatus, and significantly reducing the size of the dried solid particles can be controlled during the drying process.

This object is achieved according to the invention with the measures of the characterizing part of claims 1, 43, 2 to 70.

Advantageous embodiments of the invention are specified in the subclaims.

The invention provides for the fine dispersion of the pre-dewatered thick matter in the spray zone of the centrifuge to be uniformly enforced with a high concentration of already dried particles and for these dispersed thick matter particles to be well distributed in the drying gas. The mass of the sprayed damp small particles in the dryer room should be applied evenly to the surface of the drier particles located in and around the spray zone. The dwell time in the spray zone of the particles, which increase in size due to build-up granulation and at the same time dry, can be adjusted by the speed of the hot gas. The relative velocity of the hot gas compared to the constantly moistened surface particles should be as large as possible to ensure that the moist, enlarging solid particles in the fluidized bed and during the subsequent pneumatic transport dry very quickly.

In a variant of the combined dehumidifying device according to the invention, the active chamber walls in the dryer are designed, for example, outside the rotating centrifuge drum in such a way that a dense fluidized bed is formed around the spray zone and no ejected moist particles hit the dryer walls directly. The fine, moist and sticky particles dispersed by the centrifuge should accumulate on the surface of the constantly moving particles present in the fluidized bed and enlarge them. The flow of the hot gas is specifically influenced by guide and guide plates installed in the dryer room in order to achieve an even distribution of solids and gas, to avoid dead spaces and to ensure intensive contact of the hot gas with the moist, constantly increasing solid particles.

Perforated walls through which gas flows are also suitable for preventing wall encrustation in the combined dehumidifying device due to moist, sticky, thick matter particles if the inflowing hot gas keeps the sticky particles away from the walls until the particles on the surface have dried sufficiently and then at a lower moisture content lose their tendency to adhere. Particularly in the case of organic sludges with a pronounced glue phase, the tendency to adhesion is particularly high in certain moisture ranges and, according to the invention, can be overcome in the fluidized bed by granulation in the case of this drying device.

The drying room can be divided into zones with different gas velocities in order to specifically influence the particle concentration and the particle sizes in the individual areas of the drying room.

The gas distribution and velocity required for the production of the fluidized bed can be designed differently by the inflow surface.

The average particle size and the particle size distribution of the dry product can be controlled in a targeted manner by blowing smaller solid particles that have already dried into the spray zone of the centrifuge. The radially outward spray of pre-dewatered fine solid particles continuously generated by the centrifuge hits the large number of surfaces of the blown solid particles in the surrounding fluidized bed. The grain shape can also be influenced in a targeted manner. Smaller dry matter particles from the selective The fluidized bed or sieved fractions of the dry product can be recycled to the vicinity of the spray zone for granulation or introduced with the hot gas.

The larger particles formed by the build-up granulation have a higher swarm sink rate and sink downward within the fluidized bed or are preferably in zones with a higher gas upward speed. The larger particles that have sunk into the lower area can preferably be transported out of the dryer room by means of conveying devices in the gas distribution floor.

The geometrical design of the zone in the spray area of the centrifuge can ensure that there are primarily smaller particles with a lower swarm sink rate, the diameter of which should be increased.

The temperature distribution in the individual fluidized bed areas can also be controlled by introduced hot gases, by heating the wall surfaces or by heating pipes in the fluidized bed.

Due to the build-up granulation in the solid spray zone of a centrifuge, preferably a solid-bowl screw centrifuge or a centrifuge with a sieve part, in the surrounding fluidized bed and the described measures, a dry product with large granules can be produced in a targeted manner, without the advantageous combined dewatering and drying in a single machine with very high heat transfer rates and large volume-related evaporation rates.

In another variant of the combined dehumidifying device according to the invention, elements protruding from the outside of the rotating centrifuge drum into the dryer space are attached, which light up the gas flow and ensure a strong counterflow and turbulence in the vicinity of the spray zone of the centrifuge solids discharge.

In order to reduce the high ejection speed of the fine solid particles sprayed from the dewatering centrifuge and to limit their flight path, fixed or moving baffles with rigid or elastic active surfaces can be installed in the spray zone, which completely or only partially surround the centrifuge discharge zone so as not to obstruct the hot gas flow ,

In the case of single or ring-shaped baffles rotating with the centrifuge, multiple deflection bowls or cones are recommended, since the braking effect on the solid particles is not as strong as with non-rotating baffles. A multiple deflection distributes the sprayed solid better in the circumferential direction and in the width in Gas flow. A better distribution in the gas flow is also achieved by a number of oppositely displacing the solids discharge openings in the axial direction.

The baffles built into the spray zone can also completely or partially direct the damp fine solid particles sprayed out into other gas-flow zones in order to preferably build up even smaller solid particles or to better distribute the solids in the gas stream. Drum parts of the dewatering centrifuge that are covered by the gas flow, as required, for example, with full-screen centrifuges, can be supplied with solid spray mist by targeted particle deflection and a hot gas flow can be passed through them.

Extended drying rooms located immediately before, in and above the spray zone of the centrifuge allow selective drying of the larger solid particles by the formation of a circulating fluidized bed.

The degree of drying of the solid granules can be further increased by downstream convective flight dryers integrated in the pneumatic conveying line before the separator or long-term transport dryer after the separator. The residence time of the solid and the relative speed to the drying hot gas can be greatly increased by impact surfaces and deflection surfaces in the after-dryer due to the braking effects.

The advantages that can be achieved with the invention are, in particular, that instead of a large number of devices and apparatuses for the treatment of fine-grained, industrially produced suspensions and products, a single, compactly constructed multifunctional apparatus is present in a continuous manner of operation and with a high throughput, which is several at the same time be able to carry out ongoing work steps in one apparatus, control the granulate size, increase product quality, prevent incrustation and reduce investment and operating costs.

The high heat transfer rates result in a number of advantages, such as low energy consumption, small compact design, small RoJ diameter and apparatus, as well as low investment and operating costs.

By arranging the dryer space around and above the spray zone of the pre-dewatered solid, the possible dryer volume can be made relatively large despite the small centrifuge, since the dryer housing according to the invention is independent of the total length of the inner dewatering centrifuge. The evaporation capacity is adapted to the high product throughput of the centrifuge. Due to the cross flow of the solids discharge of the centrifuge, the performance and size of the dryer can also be adapted to the requirements regardless of the size of the dewatering centrifuge.

With less mechanical pre-dehumidification by the centrifuge, an even greater water evaporation capacity is required. The required drying gas quantities for, for example, 51 / h water evaporation capacity per machine require very large flow cross sections. The centrifuge with its solid spray zone is now only a product entry device and atomizer for the pre-dewatered thick matter.

According to the invention, the entire evaporation capacity of the drying system is no longer provided by the combination machine alone. The downstream post-dryer and the pneumatic transport using hot gas in the lines also provide part of the dryer performance of the system.

It is important for the overall function that the pre-dewatered product is converted into a pneumatically transportable degree of dryness by the multifunction machine.

In addition to these advantages of the invention, the avoidance of incrustations and caking should also be mentioned in the case of sludges which are difficult to dewater. As a result, the area of application and application of the combined dewatering and drying machine is also extended to products which, after mechanical dewatering, give thick materials which are very sticky or have a very high moisture content and cause great problems in other dryers. Interruptions in operation due to mechanical pre-dewatering in the centrifuge that is too moist and the associated costs are also avoided.

The advantages that can be achieved with the invention are, in particular, that the multifunction machine generally handles the difficult drying sections of the glue phase. overcome without backmixing of additional substances.

The post-drying is thus relieved in the moisture evaporation. Another advantage is that existing sludge centrifuges for only dewatering can be retrofitted in the usual design of full-shell centrifuges or screen screw centrifuges in the manner according to the invention to multifunction machines in which mechanical dewatering, drying and granulation can be carried out.

For the first time, the invention nuances the advantageous dispersing properties of continuously charged and spraying centrifuges (which include solid bowl screw centrifuges, solid bowl nozzle centrifuges, sieve screw centrifuges or nozzle separators). are) as an atomizing machine, so that, according to the invention, a sludge centrifuge is now assigned two main functions instead of the previous, sole separation function: firstly, the mechanical separation of thick matter from the suspension, and secondly the dispersion and atomization of the separated thick matter into the smallest particles and their distribution and drying by a stream of drying gas. This second function, namely the advantageous use of the fine dispersing properties of the thick material discharge of a sludge centrifuge in the construction z. B. a full jacket centrifuge, has not been used technically for the purpose of spray drying.

Further details, advantages and features of the invention are explained in more detail with the exemplary embodiments with reference to drawings.

Show it:

1 shows the longitudinal section of a combined centrifuge dryer with a solid-bowl screw centrifuge as an atomizing machine, with a solid fluidized bed around the entire centrifuge drum.

2 shows the combined centrifuge dryer from FIG. 1 in cross section

3 shows a combined centrifuge dryer with all additional system parts and peripheral devices.

4 shows a combination of a solid bowl centrifuge with a flow-through dryer with solid enrichment only around the spray zone of the decanter.

5 shows a combined centrifuge dryer with a vertically arranged decanter as a spraying machine in the fluidized bed with an overflow weir for the solid.

• Fig. 6 shows a cross section of a combined centrifugal dryer bodeπ as a combination of solid shedding a solid bowl screw centrifuge with a circulating fluidized bed dryer without perforated plate ^'and solid baffles.

7 shows an aniagram for self-inerting cycle gas operation with a centrifuge dryer and pretreatment of the suspension by external dry material backmixing.

8 shows a combined centrifuge dryer with a rotating fluidized bed and internal solids return

9 shows the cross section to FIG. 8 10 shows a schematic longitudinal section of a combined centrifuge dryer as a combination of the solid discharge of a screen screw centrifuge with two different filtrate outlets and a combination of different impingement cones.

11 shows a longitudinal detail view for the thermal expansion-appropriate mounting of the combined centrifuge dryer on the centrifuge frame and for sealing the dryer housing against the rotating centrifuge components.

12 shows a longitudinal section through the spray zone of the combined centrifuge dryer as a multifunction machine with a dispersing aid through a fan wheel with pin mill and rear-ventilated baffle cone.

13 is a view of the completed system of a combined centrifuge dryer with a circulating fluidized bed dryer, with a second after-dryer before and a granulating device for the product after the cyclone separator.

The combined centrifuge dryer shown in longitudinal section in FIG. 1 and in cross section in FIG. 2 is a dewatering and drying machine and has a solid-bowl screw centrifuge 1 of a known type. In addition to the mechanical dewatering, the solid-bowl screw centrifuge also serves as an atomizing machine for the pre-dewatered solid and is surrounded by a solid fluidized bed around the entire centrifuge drum 1. The outside is cleaned automatically by centrifugal force. Instead of the solid-shell screw centrifuge 1 shown, other centrifuges suitable for dewatering, for example sieve-shell screw centrifuges, solid-shell nozzle centrifuges, 3-phase separation centrifuges or separators, in which the separated solid phase is then to be dried, can be used. The solid-bowl screw centrifuge 1, which is referred to below as an example of a dewatering centrifuge, has a rotating drum shell 2 which is rotatably supported at its axial ends on roller bearings 3. The drum shell 2 tapers conically at one of the two ends and is at a ^" fine tapered end with discharge openings. 4, which forms the discharge zone 5 for the pre-dewatered thick matter 6. The liquid sludge 8 fed into the interior of the centrifuge 1 through a sludge pipe 7 is separated into a thick matter 6 and a clarified liquid 9 in the centrifuge 1 due to the centrifugal force ^. which at the other end of the drum jacket 2 is sprayed out of the centrifuge 1 into a separate housing, the centrate chute 10. The dryer directly surrounding the centrifuge 1 is through an outer dryer housing

11 and an inner housing, not shown, surrounding the rotating drum 2

12 or also formed by the drum 2 itself, and by the two end walls 13 and 14. The drying gas 15 is through hot gas lines 16 from below under the Fluidized bed 17 initiated. The fluidized bed 17 consists of a perforated sheet with round or slot-like holes through which the hot gas 18 flows. The pressure drop occurring when flowing through should be so great that the hot gas 18 enters the dryer chamber 19 evenly in the longitudinal and transverse directions. The free hole-area ratio of the fluidized bed 17 is normally chosen so that there is a pressure drop which corresponds approximately to the pressure loss of the fluidized bed itself. The evenly entering hot gas 18 flows around and penetrates the thick matter 6 dispersed in the form of fine particles through the entire circumference through the decanter solid discharge openings 4. A bubbling gas-solid fluidized bed forms in the entire dryer space 19, which flows over the rotating solid bowl centrifuge 1 from the outside and encloses it. So that the radially emerging solid spray 6, consisting of pre-dewatered moist particles, does not wet the dryer wall 13 and also to pre-dry the sticky particles, an impeller 20 is attached to the rotating drum jacket 2 next to the discharge zone 5, which hot gas in the direction of the solid Spray 6 blows and deflects it in the axial direction. The solid spray mist 6 dispersed into the fluidized bed is deposited on the already dried particles of the fluidized bed in motion and increases these particles. The hot gas 18 dries the externally moistened particles very quickly, since a large specific surface area of the solid particles 6 is available for heat and material exchange. The gas 21 emerging at the upper edge of the bubbling fluidized bed and cooled by the drying is collected in the upper region of the dryer housing 11 and suctioned off at the suction pipe 22. The lighter, smaller particles and the dust are discharged with the gas 21. The larger particles 23 formed by the build-up granulation sink within the fluidized bed down to the fluidized bed bottom 17 and are continuously discharged by the screw conveyor 24. The hot gas 15 introduced at 16 from below is distributed through the inclined fluidized bed floors 17 according to their free hole cross section and flows into the dryer chamber 19 at different gas velocities 8. Sinking larger particles automatically pass through the inclined position of the perforated fluidized bed floors 17 into the transport screw 24 which is not or only slightly flowed through by the gas and is discharged. The upward velocity 47 of the gas in the fluidized bed can be designed by the angle of inclination and the perforation of the two fluidized bed bottoms 17 such that large, dried, large particles that reach the conveyor screw 24 only through built-up granulation.

Due to the inclination of the fluidized bed bottom 17 towards the screw conveyor 24, all of the larger particles that have sunk are conveyed towards the center and discharged. The size the sinking particles 23 can be controlled via the speed of the gas 18. The denser the solids concentration in the dryer room 19, the more dried particles are discharged with the exhaust gas 21 due to the lower swarm sink rate. Due to the design of the dryer housing 11, the free area ratio of the fluidized bed 17, the speed of the screw 24 and the amount of hot gas 15, the separation cut of the grains can be determined, which are discharged at 22 or below at 24. The dryer housing 11 can be extended upwards in a manner not shown instead of the vertical walls. A side opening with an adjustable overflow weir can also be provided in the end wall 14 as an additional solids outlet. Standing, moving or rotating impact surfaces or deflection surfaces 25 can also be installed around the discharge zone 5.

In Fig. 3, a combined centrifuge dryer completed with other plant parts and peripheral devices is shown as an example. Of course, other apparatuses, paths, circuits, links can also be arranged around the combined centrifuge fluidized bed dryer, for example for one-time gas continuous operation or recycle gas operation. The centrifuge dryer consists of the centrifuge rotor 1, which is partly built into the dryer, with an outlet 10 for the mechanically separated centrate liquid 9 and a solids discharge zone 5 at the other end. The dryer housing 11 is divided into four sections in the axial direction. The first section 26 in the vicinity of the solid spray zone 5 serves to introduce dried solid particles mixed with carrier gas, which are constantly wetted externally by the moist solid spray 6 of the centrifuge 1. The introduced dry matter granules ensure that the spray mist 6 is constantly surrounded by absorbent dry, free particles of the fluidized bed. The moist spray mist 6, which is enveloped by particles, cannot be sprayed directly onto the dryer walls, it is shielded by the fluidized bed. The second section 27 of the dryer housing 11 is used to introduce hot gas 18 into the fluidized bed, which is made uniform in its entry speed by the perforated fluidized bed floor 17. In the third section 28, hot gas 18 is also introduced, the temperature or empty pipe speed of which may, however, be different. In the fourth section 29, cooled gas 21, mixed with dried solid particles 30, is drawn off from the fluidized bed space 19. The circulating gas blower 31 on the one hand ensures the solids circulation of dried grains 30 in the centrifuge dryer from 29 to 26, and on the other hand also for the transport of at least some of the dried solids grains to the separator 32, which is shown as an example as a cyclone. The freed from the solid air 33 is supplied to the scrubber 35 to a smaller extent by the fan 34. The larger proportion of the dust ten exhaust gas 36 is mixed with hot flame gases 37 again sucked in by the blower 38 and pressed again into the centrifuge dryer 11. The hot flame gases 37 are generated in the gas heater 39 by a burner 40 which burns the fuel 41 with a low excess of pollutants. Part of the scrubbed exhaust gas 43 is reintroduced as a low-oxygen cooling gas 44 around the burner 40 to the gas heater 39 and thus returns to the gas cycle. The excess gas portion 45 is blown off the system through the chimney as dedusted and washed exhaust gas 46. The water evaporated in the centrifuge dryer 11 is condensed in the washer 35 by cooling and discharged with the washing water 48 and removed from the dryer circuit.

As described in more detail in EP 0591 299, the constant supply of oxygen-poor flame gases 37 and the removal of moist exhaust gases 45 from the drying system result in a circulating gas atmosphere 33 which is greatly depleted in the oxygen content by CO ₂ self-inerting. This prevents dust explosions and spontaneous combustion of dry products at risk of fire. The dry product 30 separated in the separator 32 is discharged, for example, via a cellular wheel sluice 50. The larger granules 23 formed in the dryer chamber 19 sink to the fluidized bed 17 and are discharged from the dryer by the conveyor screw 24 and the discharge lock 51. The two Tock ^products' coarse pellets 52 and 53 smaller pellets can be mixed together, or further processed separately for different purposes. In this combined centrifuge dryer according to the invention, the pellet sizes can be specifically controlled by the possible setting parameters and produced in the desired grain sizes.

Fig. 4 shows schematically in longitudinal section a combination of a solid bowl centrifuge 1 with a centrifuge dryer, in which only the solids discharge and spray zone 5 of the centrifuge 1 is integrated into the surrounding centrifuge dryer 11. In this embodiment, a hot gas stream 15 is directed from below the solid spray 6 radially ejected by the centrifuge 1 in order to brake the solid particles rapidly downwards. On the drum shell of the centrifuge on both sides of the solids discharge zone 5 open, rotating self-cleaning impellers 20 are attached to the outside, which constantly suck the gas sideways at the solids discharge openings 4 and generate a strong negative pressure at the discharge zone 5. The negative pressure 55 in relation to the surroundings of the dryer chamber 19 causes gas laden with particles to flow rapidly from the fluidized bed in the discharge zone 5 radially from the outside inwards, which is directed in the opposite direction from the sprayed solid spray 6 with its moist and sticky particles. By countercurrent from gas and fine dry particles. the moist solid particles are braked very quickly, coated and dried in a very short time. Due to the very high relative speed that occurs, extremely high heat and mass transfer rates are achieved. As a result, the specific water evaporation capacity and volume-related dryer capacity are greatly increased. These transmission powers cannot be achieved in a normal fluid bed dryer. The relative speed between hot gas and moist particles in a normal fluidized bed dryer according to the prior art is approximately 1-2 m / s, whereas relative speeds of 30 to 60 m / s are achieved in this arrangement according to the invention. Due to the geometrical design and the corresponding gas velocity, the centrifuge dryer can be operated in continuous operation with a single gas passage, but it can also be operated with a side gas and product outlet in cycle gas operation. If the gas-permeable perforated plate 17 is omitted in order to equalize the speed of the incoming drying gas 15 as in FIG. 6, the opening angle 54 of the dryer housing 11 above the hot gas line 16 must be reduced and the centrifuge dryer builds higher.

5 shows a centrifuge dryer with a vertically arranged solid bowl screw centrifuge 1 as a solid spraying machine in the fluidized bed. Instead of the solid bowl screw centrifuge 1, a nozzle decanter or a nozzle separator with a vertical axis could also be installed. The solid bowl screw centrifuge 1 is supported by the two roller bearings 3 below and above. The frame 66 for the upper bearing 3 is guided as an axis cross through the solid fluidized bed. The solid-bowl screw centrifuge 1 is supplied with the liquid sludge 8 via an insulated line 7. The separated liquid 9 flows out at the bottom via a center chute 10, the pre-dewatered solid is flung out of the solid discharge openings 4 as a solid spray 6 at the top of the fluidized bed. The fluidized bed dryer shields the walls 11 from the wet spray ^'6 by the many moving particles. The hot gas 15 is pressed in from below through insertion shafts 16 under the fluidized bed 17 and enters the fluidized bed 19 at a uniform rate at 18. Heat is again supplied to the hot gas, which cools due to water evaporation, through heating pipes 55 located in the fluidized bed, and heat is also transferred through the heating pipes 55 to the contacting solid particles. This measure significantly increases the volume-related evaporation rate. The smaller, dried solid particles 53 are discharged via a height-adjustable overflow weir 56. The dust-containing exhaust gas 21 leaves the centrifuge dryer through the suction pipe 22. Coarser particles 52 that have sunk into the fluidized bed can be removed by a slit weir directly above the fluidized bed bottom 17. The height of the fluidized bed 58 is highest near the spray zone 6, in the direction of flow towards the dryer outlet 56 ne 6 highest, in the direction of flow towards the dryer outlet 56, the layer 58 becomes somewhat lower due to a slope.

6 shows in cross section a combined centrifuge dryer as a combination of the solid discharge of a solid bowl screw centrifuge 1 with a circulating fluidized bed dryer 11 without perforated plate bottom.

The centrifuge dryer shown is constructed similarly to that in Fig. 4, however, the circulating fluidized bed 59 which is formed is mainly above the centrifuge rotor 1. In the lower half 57 around the centrifuge rotor 1, the velocity of the hot gas 15 entering at 62 is so high that all follow pre-dewatered solid particles 6 thrown off at the bottom are immediately carried upwards by the hot gas 15. The dryer housing 61 around the solids discharge zone 5 is constructed like the diffuser part of a gas venturi nozzle and is open at the top. The narrowest point in the Venturi nozzle 62 for the hot gas 15 replaces the perforated plate base 17 for the fluidized bed. A circulating fluidized bed 59 is formed in the upper conically expanded dryer section 63. The larger or even wetter and thus heavier solid particles 52 in the upper dryer part 63 reverse their upward direction of movement due to the greatly slowed gas speed and they fall down again into the dryer part 61 with a higher upward speed. This statistically running circulation movement for heavier particles 52 continues until the particles 53 are sufficiently dried, lighter or decayed and are also discharged upwards at 22 and are pneumatically transported in the subsequent pipeline 64. The part of the dryer housing 61 built around the centrifuge rotor 1 is separated from the other parts of the dryer housing 63, 16 by the two elastic compensators 65 in order to allow thermal expansion and to transmit no vibrations from the centrifuge 1 into the adjacent system parts.

A detailed front view of the combined centrifuge dryer for the thermal expansion-appropriate mounting of the dryer housing 61 of the combined centrifuge dryer on the centrifuge frame 66 is shown. The conically expanded dryer housing 61 expands greatly when the dryer heats up compared to the components 1 and 66 of the dewatering centrifuge which remain cold. The dryer housing 61, consisting of the conical walls 61 and the two side walls 13 and 14, which are sealed against the rotating components of the centrifuge, should move in its central position relative to the axis of rotation 67 and along little along despite all-sided expansion. It is therefore connected to the cold, rigid frame 66 of the centrifuge by laterally flexible support elements 68. When the dryer housing is enlarged, the spring elements 68 cause lateral restoring forces which the dryer housing 61 despite keep stretch in its original center position to the turning center. Wound steel springs, rubber springs, vertical bending bolts, or vertical or inclined leaf springs can serve as laterally resilient support elements 68. The natural frequencies of the housing support 68 must be coordinated in terms of vibration so that resonance vibrations and movements cannot occur when the centrifuge 1 is started, operated and switched off. In the zones 70 with the smallest distance of the solid discharge zone 6 from the

Dryer walls 61, in addition to the elements described in FIG. 11, can be installed in the discharge zone 5, rigidly supported rigid baffles 60, or elastic, resilient or oscillating baffles 69, which clean themselves from solid encrustations. The flat or curved baffles 60, 69 can also be installed at an angle to the spray level of the solid discharge or, like the encrusted dryer walls 61, 16, 63, 13, 14, can be set in a cleaning vibration by a drive 71. To keep the housing walls 61 close to the rotor 1 free, these can be flowed behind and perforated, vibrate, guided gas flows or targeted gas jets can also be used.

FIG. 7 shows a system diagram for self-inerting cycle gas operation with a centrifuge dryer 49 with a circulating fluidized bed according to FIG. 6 and a pretreatment of the suspension 8 by external dry material backmixing 73 into the liquid sludge. The centrifuge dryer 49 consists of the dewatering centrifuge 1 or 87 and is supplied with hot gas from below by the hot gas generator 39 with burner 40 via the tube 16. The dried product is transported through the suction pipe 22 to the cyclone separator 32, where it is discharged from the gas cycle. The dedusted exhaust gas 33 is conveyed from the circulating gas blower 31 into an exhaust gas component 43 to the scrubber 35 and into a circulating gas component 36 again to the hot gas generator 39 and mixed with the flame gas 37 from the combustion to form the drying gas 15. If the dried product 30 fails, the fine fraction 75 and dust of the product 30 are sucked off by cross air 76 and transported to a separator 77, which is shown as an example of a cyclone, but also z. B. operated a dust filter or a scrubber with liquid sewage sludge can be. The continuously occurring fine fraction 75 separated in the separator 77 is continuously mixed into the suspension 8 through the discharge lock 51. If necessary, the suspension enriched with the granular dry substance which promotes drainage can also be added with precipitation or flocculation aids 78 in the centrifuge 1, 87 for better clarification by wet mechanics. The dedusted exhaust air 79 is also fed to the scrubber 35 for final cleaning. The exhaust fan 34 sucks the entire Exhaust gas quantity 45 to the chimney 80. The suitable proportions of exhaust gas quantity can be controlled via control flaps 81. The CO ₂ self-inerting and condensation of the moisture takes place in a manner similar to that described in FIG. 3.

A combined centrifuge dryer with a rotating fluidized bed and internal continuous material return is shown in longitudinal section in FIG. 8 and in the associated cross section in FIG. 9. The hot gas 15 enters in several longitudinal sections 27, 28 through tangentially arranged insertion shafts 16 between the dryer housing 11 and the cylindrical or frustoconical perforated fluidized bed cylinder 83. Due to the tangential inflow process and the type of perforation of the screen cylinder 83, in the form of slots, beads, Conidurblechen or, for example, Gridboden- shaped inlet openings, the tangential inflow of the hot gas 18 and its rotation is forced inside. The pre-dewatered solid is sprayed through the discharge openings 4 of the rotating drum 2 at one end of the drying room. In order to keep the moist spray 6 away from the end wall 13, a conical or bowl-shaped baffle plate ring 84 is on the end wall 13 or on the drum. 2 attached, which deflects the spray in the axial direction. A rotating gas-solid fluidized bed 85 is formed within the cylindrical perforated plate 83 and is carried by the inflowing rotating hot gas 18. The layer thickness 86 of the rotating solid fluidized bed 85 which forms depends on the grain sizes, the centrifugal field strength, the gas entry speed, the transport speeds in the axial and tangential directions and the centrifugal swarm density. The solid spray 6 is sprayed onto the rotating fluidized bed 85 from the inside and enlarges the already rotating solid particles. Since the radial flow velocity of the particles can be greatly increased by the centrifugal field without the particles being entrained immediately, the heat and mass exchange rates achieved in the rotating fluidized bed 85 are much higher than in a fluidized bed in the earth's gravitational field. The fluidized, rotating fluidized bed 85 migrates in the axial direction through the dryer to the suction pipe 22 at the end of the dryer. In order to increase the particle concentration and the layer thickness of the rotating fluidized bed 85 in the vicinity of the discharge zone 5, dry particles are drawn off at 29 and returned to the fluidized bed at 26. The trigger 29 and the introduction 26 can also take place in the tangential direction. The solid blower 31 takes over the return transport of the gas-solid mixture. The perforated inner cylinder 83 can also partially consist of solid sheet metal rings or be interrupted by these. The directions of rotation of the centrifuge drum 2 and the rotating fluidized bed 85 can be the same or opposite. FIG. 10 shows a schematic longitudinal section of a combined centrifuge dryer 49 as a combination of the solid discharge of a sieve screw centrifuge 87 with two different filtrate outlets. The screen centrifuge dryer 49 consists of the centrifuge rotor s 91 projecting into the dryer with its solids discharge 4, with an outlet 10 for the mechanically separated clarifying centrate liquid 9, the conically shaped housing 93 for the sieve filtrate 92 and a solids discharge zone 5 at the end of the sieving zone 91. The housing 11 of the centrifuge dryer 49 is divided in the axial direction into several sections for hot gas introduction 16, product outlet 61, sieve filtrate housing 93, centrate chute 10. The suspension 8, if necessary mixed with precipitant 78, is added to the sieve screw centrifuge 87 through an inlet pipe 7 and enters the rotating separation space at 88. In the solid jacket part 2 of the centrifuge, the solid sediments on the drum jacket 2, the clarifying filtrate 9 is injected into the centrifuge chute 10 via direct-flow centrifuges 87 in the case of direct-current centrifuges, and via counter-flow centrifuges directly through the end wall openings. The pre-dewatered solid transported from the screw 89 on the cone inwards to the sieve part 90 of the centrifuge drains 91 further residual liquid on the rotating sieve. This so-called sieve filtrate 92 is thrown out through the sieve 91 into the sieve filtrate housing 93 and flows off at 92. The screen screw centrifuge 87 is able to mechanically dehumidify very large solid mass flows, provided the fine-grained solids can be retained by the rotating screen 91. The solid tasted through the sieve 91 is thrown out at the solid discharge 4, agglomerates are crushed at the armored rotating impact cone 103, distributed in the circumferential direction and somewhat deflected and comes into contact with the inflowing hot gas 15 at 107 in the discharge zone 5. The baffle cone 84 which is flowed behind is exemplified here as a combination of a rotating baffle cone 103 for the distribution in the circumferential direction and an outer, non-rotating deflection cone 84. All sprayed solid particles 6 are carried upwards into the dryer 19 and the speed in the upper dryer diffuser part 63 is slowed down, similar to that in FIG. 6. The rotating sieve 91 can be designed as a cylindrical or slightly conical sieve basket. It can be designed as a welding gap sieve, loop sieve or as a laser finely perforated sheet and consist of wear-resistant stainless steel, ceramic or hard metal. The slope of the screw conveyor 89 can be less in the sieve part 90 of the centrifuge than in the solid casing part 2. Washing liquid or superheated steam 82 or hot gas can be introduced inside the screen basket 91 in order to improve the mechanical dehumidification in the screen part 91 and to preheat the solid 6 for the subsequent drying. The screen screw centrifuge, which is mostly used in processing technology, is capable of mechanically mechanically adjusting very high solids mass flows of approx. 50 1 / h and more to high TR - Values of e.g. B. with coal to dehumidify approx. 82% TR, provided that the fine-grained solids can be retained by the sieve. A non-illustrated race track with a tangential solid outlet upwards or with partial shielding on the sides or downwards according to the prior art can also be attached to the solids discharge 4 in a targeted manner. The particles 6 come into contact with the inflowing hot gas 15 at a high relative speed of 50-80 m / s in the discharge zone 5 and dry off the surface very quickly in milliseconds. All sprayed solid particles 6 are carried upwards into the dryer 19 and then greatly slowed down to approx. 5-15 m / s. The applicable temperatures of the entering hot gas 15 are very high up to 500 ° C., since the rotating centrifuge rotor is thermally very well shielded by the diffuser-dryer housing 61 and the conical screen filtrate housing 93. The hot dryer housing 61 is mechanically completely decoupled from the dryer components durch by the elastic expansion compensators 65 and is shielded by the heat insulation 95. The hot dryer housing 61, 94 is also thermally separated from the cold screen filtrate housing 93. In order to prevent the rotating screen basket 91 from becoming blocked by the screen filtrate 92 loaded with solids, a washing nozzle device 96 is fitted inside the screen filtrate housing 93.

Fig. 11 shows a longitudinal detail view from a construction drawing similar to Fig. 4, 6, 10, for thermal expansion-appropriate support of the combined centrifuge dryer 49 on the centrifuge frame, for sealing the hot housing walls .13 and 14 of the combined centrifuge dryer 49 against the rotating centrifuge components and Distribution of the solid spray 6 over the entire dryer cross section.

The housing end walls 13 and 14, which are slightly displaceable by thermal expansion, are tightly connected to the rigid labyrinth supports 99 via elastically deformable, heat-resistant, multi-layer fabric compensators 97. The labyrinth carriers 99 are screwed rigidly to the centrifuge frame 66 and carry the non-contact labyrinth seals 100 which are set against the rotor parts with a narrow gap. The labyrinth supports 99, like the roller bearing housings 3, are rigidly connected to the supporting centrifuge frame 66, as a result of which the narrow, contact-free labyrinth gaps 101 do not change even during thermal expansions or movements of the dryer housing 13, 14, 61, 94 or the rotating rotor surfaces of the centrifuge 1, 87 can touch. The hot, expanding dryer housing 13, 14, 61, 94 is fastened to the cold centrifuge frame 66 by means of, for example, 4 laterally resilient bolts 02, so that despite thermal expansion of the hot dryer housing similar to that described in FIG. 6, the narrow labyrinth gaps 101 remain constant. In order to better distribute the solid particles 6 thrown out by the centrifuge solid discharge 4 over the entire dryer cross-section and to avoid incrustations of the dryer housing 61, 94 near the rotor 1, 4, a two- or multiple-action rotating impact device 103 is arranged above the individual solid waste Throw holes 4 attached. Due to the multiple impact and deflection of the trajectory of the solid particles 6 after leaving the discharge openings 4 on impact surfaces 103 connected in series, larger clumps of solid are more easily comminuted and the spray mist is better distributed in the circumferential direction.

The impact and deflection device 103 can be arranged concentrically one above the other on the entire circumference in the radial direction, or a single impact and deflection plate 104 with different directions and angles 105 is attached above each discharge opening 4 of the centrifuge rotor 1. The various discharge openings 4 can be distributed not only on the circumference, but also in the axial direction over the flow cross section of the dryer.

As a result, the pre-dewatered ejected solid particles 6 are distributed more evenly and with a locally lower surface concentration over the entire width of the dryer housing and in the hot gas 15 flowing in from below, for example. The impact and deflection device 103, 104 can be a combination of a plurality of deflection elements, which all rotate or consist of a combination with alternating rotating and non-rotating impact elements.

The deflection angle 105 of the individual impact elements 104 can be designed differently for each impact element 104 in order to improve the spatial distribution of the solid mist sprayed from the centrifuge drum at 4.

The deflection surfaces can also be aligned in the axial direction, rotated to this, in or opposite to the direction of rotation, in order to achieve the best possible spatial volume distribution of the sprayed solid mist in the hot gas flowing through. Each individual discharge opening 4 for the solid 6 can be operated by at least one impact element for directional deflection.

The impact surfaces 104 may have applied wear protection in the form of attached hard material plates or welded-on layers.

If the centrifuge dryer is designed as shown in FIGS. 1-10 described above, the solid spray 6 can be carried along well distributed in the drying room by the drying gas 15 and can be dried further above the rotor 1, 87.

Fig. 12 shows a longitudinal section through the spray zone 5 of the combined centrifuge dryer 49 according to FIGS. 4, 6, 7, 10, 11, as a multifunction machine with an additional dispersing aid through an impeller 20 with pin mill 106 and impact cone 84 and second hot gas inlet 18 through the downward, non-rotating baffle cone 84. For particularly sticky products 6 that have been mechanically dewatered by the centrifuge 1, additional comminution of the ejected solid particles 6 is advantageous. The subsequent comminution of the solid particles 6, which is superimposed on the drying process, constantly creates a new surface which is exposed to the inflowing hot gas and leads to rapid drying of even very poorly dewatered products.

Due to the blower blades 20 located on the rotor 2 of the centrifuge 1, large amounts of hot gas are continuously fed into the discharge zone 5 and through the comminution tools 106. The baffle cone 84, which is open at the bottom, additionally guides a portion of the drying gas 15 flowing in from below through the annular gap 107 into the discharge and comminution zone 5. The ratios of the two drying gas quantities 15, 18 flowing in from below can be varied. It can also be, for example, the partial stream 18 a hot gas stream loaded with solid dust 75, the solid of which is used for coating and enveloping the sticky solid particles 6 in order to change their adhesive properties.

A pin mill 106 with two fixed pins and one row of pins rotating with the fan blades 20 is shown here as an example of the comminution unit. Of course, several rows of pins can also be arranged. In special cases, the comminution unit 106 can also be omitted and the rotating fan blades 20 with the opposite conveying direction increase the suction through the annular gap 107 and, in an extended form, themselves act as a comminution and scraping tool for the incrustations on the impact cone surface 84.

13 shows a view of the completed system with a very high throughput of a combined centrifuge dryer 49 with a circulating fluidized bed dryer 63, with a second after-dryer 108 before - and a press granulating device 109 after the double cyclone separator 32.

If the very low residual moisture content of the end product is required or if the mass flow is very large, it may be necessary to ensure an extended residence and contact time of the solid 6 with the hot drying gas -15 until it is separated in the cyclone 32. A prolonged contact time of the solid particles 6 sprayed from the dewatering centrifuge 1, 87 with the drying gas 15 heated by the gas heater 39 and introduced from below through the pipeline 16 into the centrifuge dryer 49 is given in the fluidized bed dryer 63 with the circulating fluidized bed 59 placed over the centrifuge dryer 49 , as explained in more detail in FIGS. 6, 7, 11. The drying gas 21 then conveys the dried product to a further after-dryer 108 in which the residence time of the product is artificially extended. In the Zig-Zag after-dryer 108 shown, the product-laden gas stream 21 is deflected several times. For reasons of inertia, the solid particles 6 with a mass density thousands of times greater than the gas follow the deflection movements only in part. They hit the wall on the outer channel surfaces 110 and are braked sharply. They reflect there again and cross the hot gas flow 21 at a high relative speed before each new impact. Due to the high relative speed of the particles 6 to the drying gas 21 of approximately 20 m / s, the drying speed of the solid particles 6 is more than tenfold compared to the subsequent drying in a pneumatic delivery pipe - Dryer according to the state of the art. The residence time of the solid 6 in the post-dryer 108 shown is increased drastically. During the deceleration and re-acceleration phases at each channel bend 110, the drying is particularly intensive. The particle distribution in the drying gas 21 over the preferably rectangular channel cross section is improved. The formation of highly concentrated product strands in round pipe cross sections, which has been very damaging to the drying speed up to now, is prevented according to the invention even with large pipe dimensions. For washing and cleaning purposes, a cleaning flap 72 is provided on the lowest elbow after the downward part. After the upward part of the apparatus 108, the pneumatic delivery pipe is again at the level of the cyclone inlet. This Zig-Zag night dryer 108 is very effective, because of the simply bent sheet metal walls 1.10 very inexpensive to manufacture and easy to integrate into the system.

The subsequently dried product 30 is then separated off in the double cyclone 32 shown and discharged from the gas cycle through the rotary valve 50. The powder 30 is transferred directly from the cellular wheel sluice 50 to a press granulator 109, which forms cylindrical pressings 52 from the powder, which are transported away by the transport screw 24. The dedusted drying gas 36, as described in FIGS. 3, 7, is again largely supplied to the hot gas generator 39 by the circulating gas blower 31. A small part is fed to the scrubber (not shown) as exhaust gas 43 and then released into the environment as chimney gas 45. Reference symbol list

1. Solid bowl screw centrifuge

2. Centrifuge drum jacket

3. Rolling bearings

4. Solid discharge openings

5. Discharge zone for the solid

6. Pre-dewatered thick matter

7. Sludge pipe for the suspension feed

8. Suspension, liquid sludge ι

9. separated, clarified liquid

10. Central chute

11. Outer dryer housing

12. Inner housing

13. bulkhead

14. Front wall

15. Drying gas

16. Hot gas line

17. gas permeable perforated sheet, fluidized bed

18. Hot gas

19. Dryer room

20.Fan wheel

21. cooled drying gas

22.Exhaust pipe

23. Larger solid particles

24. Transport screw

25. Impact areas

Section 26 in the dryer housing

Section 27 in the dryer housing

28th section in the dryer housing

Section 29 in the dryer housing

30. dried solid particles

31. Circulation gas blower

32. Separator for solids

33. Solids-free exhaust air

34. Blower

35. Washer

36. Exhaust dust removed

37. Flame gas from combustion

38. blower

39. Gas heater

40.Burner

41. Fuel

42. dropped

43. Exhaust

44. Cooling gas

45. Fireplaces

46. Exhaust

47. Drying gas upward speed

48. Wash water

49. Total centrifuge dryer

50th rotary valve

51. discharge lock

52. Coarser pellets

53. Smaller pellets

54. Diffuser opening angle 55. Heating pipes for drying gas and fluidized bed

56. Raid weir

57. Lower half of the fluidized bed

58. Height of the fluidized bed

59. Circulating fluidized bed

60. Baffles vibratingly supported

61. Dry housing diffuser part

62. Dryer housing narrowest point

63. Upper dryer section

64. Pipeline

65. Vibration compensators

66. Centrifuge frame

67. axis of rotation of the centrifuge

68. Support elements laterally compliant

69. baffles resilient in themselves

70th zone with the narrowest flow cross-section

71. Cleaning drive

72. Cleaning flap

73. Dry material backmixing

74. Cross flow classifier and cooler

75. Fine fraction of the product

76. Cross and cooling air

77. Dust collector

78. Flocculants

79. Exhaust air

80th fireplace

81. Control flaps

82. Superheated steam

83. Screen cylinder with tangential openings

84. Baffle plate not rotating

85. Rotating fluidized bed

86th layer thickness

87. Screen screw centrifuge

88. Inlet chamber

89. centrifuge screw

90. Sieve part of the centrifuge

91.Screen basket

92. Sieve filtrate

93. Sieve filtrate housing

94. conical dryer wall

95. Thermal insulation

96. Washer nozzles

97. Tissue compensator

98. dropped

99. Maze bearer

100th labyrinth seal

101. Maze column

102. resilient support bolts

103. Impact device

104. Impact and baffle

105. Angle of inclination of the baffle

106. Crushing unit

107. Annular gap

108. Zig-Zag night dryer

109. Press Granulator

110. Service areas

Claims

claims

1.Procedure for the combined dewatering and drying of suspensions, for example industrial or sewage sludge, fermentation broth or slurries, using a centrifuge, for example a continuous solid bowl screw centrifuge or sieve solid bowl centrifuge, at the entrance zone of which the suspension is applied as a pumpable mass and at the same Solids discharge zone, the pre-dewatered, sticky thick matter mass with a high residual moisture content is thrown off in the form of dispersed particles, and with a drying device for convective drying of the thrown off solid particles, the drying device forming a structural unit with the centrifuge and the dryer housing at least partially enclosing the centrifuge, and that the solids discharge zone of the centrifuge is used as an atomizing machine and as a direct entry element into the dryer, characterized in that the solid particles from the centrifuge in a ve broader zone are thrown off, deflected in their flight direction and distributed in the drying room, the solids discharge zone of the centrifuge is at least partially surrounded by a high particle concentration in the drying room, and the moist particles thrown off by the centrifuge meet partially already dried recirculated solid particles of the moving surrounding fluidized bed.

2. The method according to claim 1, characterized in that the solid particles are deflected in different directions after leaving the centrifuge for better distribution in the surrounding dryer room.

3. The method according to claim 1, characterized in that the speed of the drying gas is reduced after flowing around the dewatering centrifuge.

4. The method according to claim 1, characterized in that above the spray zone of the centrifuge is followed by a circulating fluidized bed with extended residence time for the larger particles for drying.

5. The method according to claim 1, characterized in that the deflection of the solid particles takes place in the dryer room by gas flow.

6. The method according to claim 1, characterized in that the deflection of the solid particles in the dryer room by impact on resting baffles.

7. The method according to claim 1, characterized in that the deflection of the solid particles in the dryer room is effected by impact on at least temporarily moving baffles.

8. The method according to claim 1, characterized in that the deflection of the solid particles in the dryer room is carried out by multiple impacts on stationary and moving baffles.

9. The method according to claim 1, characterized in that the solid particles are also subjected to a comminution process by the multiple deflection.

10. The method according to claim 1, characterized in that the spray zone is at least partially within a fluidized bed of whirled solid particles.

11. The method according to claim 1, characterized in that the solid spray of the centrifuge is sprayed onto the particle surfaces of the surrounding fluidized bed.

12. The method according to claim 1, characterized in that the solid spray of the centrifuge is sprayed from above onto the surface of the moving fluidized bed ''.

13. The method according to claim 1, characterized in that a build-up granulation of the particles in the fluidized bed takes place in or near the spray zone.

14. The method according to claim 1, characterized in that the fluidized bed moves at an angle to the axis of rotation of the centrifuge between 0 ° and 180 °.

15. The method according to claim 1, characterized in that the dryer walls are shielded from the spray of the centrifuge by the fluidized bed particles.

16. The method according to claim 1, characterized in that already dried particles are blown or sprinkled together with hot gas in the spray zone of the centrifuge.

17. The method according to claim 1, characterized in that the moving fluidized bed is filled with dry solid particles by recycling dry product and gas in the vicinity of the spray zone.

18. The method according to claim 1, characterized in that the fluidized bed is divided into several zones with different gassing and flow rates.

19. The method according to claim 1, characterized in that the fluidized bed is divided into several temperature zones.

20. The method according to claim 1, characterized in that at least parts of the dryer walls and or deflection surfaces are perforated and permeable to gas.

21. The method according to claim 1, characterized in that at least a portion of the wall surfaces coming into contact with the dispersed solid particles are cleaned mechanically or by blowing with gas.

22. The method according to claim 1, characterized in that the solid to be dried is preheated within the centrifuge.

23. The method according to claim 1, characterized in that the dried solid is led out of the dryer space at least in two places.

24. The method according to claim 1, characterized in that the surface moist particles from the centrifuge are coated with dry dust in the drying room.

25. The method according to claim 1, characterized in that at least one of the solid phases are treated in three- or multi-phase centrifuges.

26. The method according to claim 1, characterized in that coarse material agglomerates are recirculated because of the longer drying time.

27. The method according to claim 1, characterized in that a sifter for coarse material is added downstream of the spray zone to extend the residence time.

28. The method according to claim 1, characterized in that the selection is carried out by size in the drying room.

29. The method according to claim 1, characterized in that the spray zone near the centrifuge rotor is additionally traversed by hot gas transversely in the axial direction.

30. The method according to claim 1, characterized in that hot gas is supplied before or between a plurality of deflection devices for the solid.

31. The method according to claim 1, characterized in that the solid is still washed in the centrifuge with hot water from the exhaust air scrubber.

32. The method according to claim 1, characterized in that superheated steam is mixed into the suspension before or in the centrifuge.

33. The method according to claim 1, characterized in that before the centrifuge in the suspension drainage-promoting substances are mixed.

34. The method according to claim 1, characterized in that fine dust of the dried product is mixed into the suspension.

35. The method according to claim 1, characterized in that after the centrifuge dryer there is at least one further hot gas supply into the dryer line.

36. The method according to claim 1, characterized in that the centrifuge dryer is equipped with a diffuser dryer part.

37. The method according to claim 1, characterized in that after the centrifuge dryer, a further post-dryer with an extended residence time for the solid is connected.

38. The method according to claim 1, characterized in that a partial stream of the hot gas to the centrifugal dryer passed ^', and is fed only in the drying before the product separator.

39. The method according to claim 1, characterized in that the dewatered and dried solid is used as fuel for energy generation and subsequent use of the hot exhaust gases for drying.

40. The method according to claim 1, characterized in that the dewatered and dried solid is pelleted.

41. The method according to claim 1, characterized in that the dewatered and dried solid is then gasified.

42. The method according to claim 1, characterized in that the separation of the dried solid takes place selectively to save fuel with the use of the let through fine dust for energy generation in the hot gas generator for drying and for removing fine dust.

43. Device for performing the method according to one of claims 1 to 42, with a dewatering device for dewatering and drying suspensions with a centrifuge, preferably a solid bowl screw centrifuge or sieve solid bowl screw centrifuge for mechanical separation of a suspension, with an inlet for the supply of the sludge and with at least one outlet each for the separated liquid and the dewatered thick matter, the die-dropping zone of the centrifuge forming the dispersing and introducing element in the centrifuge dryer, with means for maintaining a high concentration of the thrown off thick matter particles and prolonged exposure, characterized in that the rotating Centrifuge drum is installed at least with its solids discharge part within the centrifuge dryer, the solid feeder forms and forms a structural unit with the dryer.

44. Apparatus according to claim 43, characterized in that the centrifuge is installed in its axial direction at an angle to the horizontal between 0 ° and 180 °.

45. Apparatus according to claim 43, characterized in that the drying space built around the centrifuge is provided with at least one gas inlet at one end of the centrifuge axis and at least one gas outlet at the opposite end of the centrifuge axis.

46. Apparatus according to claim 43, characterized in that the gas inlet and the gas outlet are only on the solid discharge side of the Zeπtrifugenachse.

47. Apparatus according to claim 43, characterized in that parts of the rotating centrifuge drum are covered, for example, by a partial protective jacket with respect to the surrounding fluidized bed.

48. Apparatus according to claim 43, characterized in that the dryer housing is sealed against the rotating surfaces of the centrifuge by stretchable movable and non-contact seals.

49. Apparatus according to claim 43, characterized in that the dryer housing is supported by elastic spring elements on the centrifuge frame.

50. Apparatus according to claim 43, characterized in that the dryer housing is provided with a joint for rotor assembly.

51. Apparatus according to claim 43, characterized in that, for example, a conical second filtrate housing is installed, in particular in the case of screen screw centrifuges.

52. Apparatus according to claim 43, characterized in that the dryer housing is partially heated from the outside.

53. Apparatus according to claim 43, characterized in that heating elements are installed within the dryer.

54. Apparatus according to claim 43, characterized in that a perforated bottom is installed at the gas inlet in the centrifuge dryer, which is divided into individual sections.

55. Apparatus according to claim 43, characterized in that a transport member with an outlet for the coarse material is installed in the perforated bottom.

56. Apparatus according to claim 43, characterized in that openings of the fluidized bed for the gas passage are circular, square, slit-like, bead-like or grid-bottom-shaped and that the free opening ratio is varied in the individual areas.

57. Apparatus according to claim 43, characterized in that at least one fan wheel suitable for introducing dry solid particles is attached to the centrifuge rotor in addition to the solids discharge openings.

58. Apparatus according to claim 43, characterized in that rotating disks, turbulence blades or comminution beaters are attached to the centrifuge rotor.

59. Apparatus according to claim 43, characterized in that at least one co-rotating, wear-protected, two-part baffle cone or directional individual baffle elements with different deflection angles are fastened on the centrifuge rotor near the solids discharge openings.

60. Apparatus according to claim 43, characterized in that there is a shredding unit consisting of rotating and non-rotating elements on the centrifuge rotor near the solids discharge openings.

61. Apparatus according to claim 43, characterized in that armored crushing and deflection plates with different deflection angles are attached to the centrifuge ^' n rotor above the individual solids discharge openings of the rotor.

62. Apparatus according to claim 43, characterized in that a standing racetrack with rotating fluidized clearing elements and directed exit is attached to the centrifuge rotor in addition to the solids discharge openings.

63. Apparatus according to claim 43, characterized in that several solids discharge openings on the centrifuge rotor are offset from one another in the axial direction.

64. Apparatus according to claim 43, characterized in that moving or vibrating baffle elements are attached to the Trόcknerwän-.

65. Apparatus according to claim 43, characterized in that the dryer walls partially consist of gas-permeable elements through which flow flows from behind.

66. Apparatus according to claim 43, characterized in that mechanical or pneumatic cleaning elements are installed in individual zones of the dryer walls.

67. Apparatus according to claim 43, characterized in that the dryer housing is connected to the gas lines by vibration compensators.

68. Apparatus according to claim 43, characterized in that the dryer housing has the narrowest flow cross section at the gas inlet.

69. Apparatus according to claim 43, characterized in that at least one after-dryer with cross-sectional widenings for the dry product before the solids separator. gen, kinks, impact zones for the solid particles is connected downstream of the centrifuge dryer.

70. Apparatus according to claim 43, characterized in that the after-dryer is designed in two-pass.