EP3775738A1

EP3775738A1 - Device, system and method for industrial drying of a suspension or solution

Info

Publication number: EP3775738A1
Application number: EP20713194.7A
Authority: EP
Inventors: Mathias Trojosky; Martin Körber; Marcel WETTRING
Original assignee: Allgaier Werke GmbH and Co KG
Current assignee: Allgaier Werke GmbH and Co KG
Priority date: 2019-04-05
Filing date: 2020-03-10
Publication date: 2021-02-17
Also published as: CA3135884A1; DE102019002528A1; JP2022526611A; US20220221222A1; DE102019002528B4; WO2020200663A4; WO2020200663A1

Abstract

A device for industrial drying of a suspension or solution which contains a solid is provided, comprising a rotatably mounted cylinder with electrically conductive properties which has a surface for receiving the suspension or solution, and an inductor which is configured to heat the cylinder inductively. Here, the inductive heating has the effect that the suspension or solution which is received on the surface of the rotatably mounted cylinder dries and the solid remains. Further devices, a system, a device pack and a method for industrial drying of a suspension or solution are also proposed.

Description

DEVICE, SYSTEM AND METHOD FOR INDUSTRIAL DRYING

A SUSPENSION OR SOLUTION

The present invention relates to a device, a device package, and a system and a method for industrial drying of a suspension or solution.

Various devices and methods for drying sludge, moist bulk materials or liquids containing solids are generally known from the prior art. The aim of drying is the (recovery) recovery of the solids contained in the liquids or moist goods in order to further process them or to transport them with reduced weight.

In industrial practice, so-called roller, disk, thin-film or belt dryers are known in particular, which function on the principle of contact drying:

The contact between a heated surface and the moist medium to be dried heats it up and the moisture in the medium evaporates, so that drying takes place. After complete drying, the dry goods are left behind.

Furthermore, known belt dryers are alternatively heated convectively by means of air or by means of thermal radiation. Disk dryers often consist of one or more packages of several circular disks arranged in parallel next to one another and arranged on a supporting shaft. The individual pane serves as a heat exchanger, which transfers thermal energy to the moist medium applied to the pane, whereby the moisture in the medium evaporates. Furthermore, the individual disk is designed as a hollow body, into the cavity of which a heated heat transfer medium flows and the disk wall by means of

Heat conduction heated to the outer surface. This gives the disc the necessary process temperature on its surface. Typical heat transfer media are, for example, thermal oil, hot water or saturated steam. Disc dryers operated with saturated steam generally use steam pressures of 1 bar (abs.) To 7 bar (abs.) With saturated steam temperatures of 100 ° C to 165 ° C. The heated disks are also rotated. This means that moist media can be narrow

Room dried and then removed. Disk dryers are used in particular in the chemical industry, pigment industry, pharmaceutical industry or in the Wastewater treatment their application.

From the patents EP 0 521 221 B1 and US 4640345 and the utility model

Disc dryers operated with saturated steam are known from JP 0G00S6267190 U. With these

In disk dryers, the individual rotating circular disks are continuously exposed to a solid-containing liquid in the lower area of their two circular disk surfaces with the aid of stationary sprayers or feed pipes. The exposed liquid dries before the disk has completed a full rotation. As a result, the surfaces of the panes can be freed from the dry material and again exposed to liquid containing solids. In order to free the disc surfaces from the adhering dry material, knives are provided which are in contact with the surfaces and scrape off the dry material, thereby converting it into a powder or granulate or in a film-like form

The following dry material chute falls. The freed surface is for the

Application of further liquid released.

Another problem with such dryer solutions is the production according to the applicable pressure equipment directives and the requirements for compliance with official acceptance of the components by a certified body such as the TÜV as well as the recurring tests of the components after a certain operating time or number of load changes. In connection with the pipelines, fittings, measuring devices and safety devices necessary for the steam supply and its regulation as well as for the condensate discharge as well as the complex production of the hollow disc body and the hollow support shaft intended for the steam supply and condensate discharge, a very complex and therefore expensive system results in the production. Another disadvantage of the known steam-operated disk dryer is that the use of heating steam as a heat transfer medium and the associated condensation of the saturated steam on the inner wall of the individual hollow disk serving as a heat exchanger achieves a high level of heat output relative to the disk surface corresponding to the state of the art , the temperature of the pane surfaces due to the condensation of saturated steam of a certain pressure is always constant and only depends on the pressure of the

Heating steam is dependent. Undercooling of the condensate in the heat exchanger is forbidden, since this could lead to critical "steam hammer" in the heat exchanger for the individual pane a temperature of the to be heated Disc surfaces can be set below 100 ° C, for example. This means that the use of steam-powered disc dryers for temperature-sensitive goods, for example, is no longer necessary

The food industry is particularly difficult because there is a risk that the dried goods will be exposed to impermissibly high temperatures through contact with the heated pane surfaces and thus be damaged.

In order to achieve surface temperatures below 100 ° C, the heating steam system would have to be operated in negative pressure, i.e. designed for pressures below 1 bar (abs.). Such a configuration would result in the overall system being significantly more complex and massive. Likewise, only a limited high pressure of the can for heating the panes

Heating steam from e.g. up to 7 bar (abs.) can be used, as the design of the panes with flat surfaces limits the design as subject to acceptance

Pressure vessels are set. The use of even higher heating steam pressures to achieve higher dryer capacities would result in a disproportionately more stable execution of the

Disk packages require, as well as the classification in a higher device category of

Pressure vessel directive mean that much more complex and / or massive construction would be required.

In addition to the disk dryers described, the drum dryers already mentioned are also known. In an analogous manner, a liquid to be dried is applied thinly to a roller and dried by indirect heating of the roller surface, in particular the jacket surface. A corresponding release device, e.g. Scraper or knife, removes the produced dry material from the roller surface after a certain roll rotation. In thin-film dryers or thin-film evaporators, on the other hand, the liquid to be dried is applied to the inner surface of a standing or lying cylindrical tube. The cylindrical tube has a double jacket structure. To heat the surface of the cylindrical tube, a heat transfer medium, e.g. Saturated steam, thermal oil or hot water, fed into the space between the double jacket to flow around the inner jacket and heat the inner jacket surface so that the applied liquid dries completely or concentrates. The drying material is detached by one or more rotatable detachment devices within the inner jacket.

Known belt dryers have a conveyor belt on which the goods to be dried are arranged. The conveyor belt is guided on rollers, for example, and is along its largest Extension direction movable. In such belt dryers, the conveyor belts with the moist material located thereon are usually acted upon by a stream of warm air or by a heat radiator, whereby heat is transferred to the material and it dries. The invention is therefore based on the object of providing a device and a method for the industrial drying of liquids containing solids, with the aid of which the disadvantages of the prior art are overcome.

This object is achieved by the device according to the invention according to claims 1 ′, 19 and 20, by the system according to claim 18, by the device package according to claim 21 and by the method according to claim 22. Advantageous embodiments of the present invention are specified in subclaims 2 to 17, 23 to 25.

The device according to the invention for industrial drying of a suspension or solution containing a solid comprises a rotatably mounted cylinder with electrically conductive

Properties, which has a surface for receiving the suspension or solution, and an inductor which is designed to inductively heat the cylinder. The inductive heating causes the suspension or solution taken up on the surface of the rotatably mounted cylinder to dry and the solid remains.

In the present invention, drying is to be understood as meaning that from one

Mixture of substances, for example a suspension or solution liquid, for example in the form of water, is removed by heating and evaporation or evaporation. Drying is a time-sensitive process, i. E. the drying or drying takes place over a certain period of time and can be ended at any point in time. In the case of complete drying, the moisture contained in the substance or mixture of substances is reduced until it is essentially completely removed from the substance or mixture of substances, so that only a dry solid remains. The drying comprises at least one phase from a plurality of drying phases, which leads to the complete drying of the substance or mixture of substances. The drying phases relate, for example, to a warming phase of the substance or mixture of substances, a further phase of the substance or mixture of substances, in which the moisture contained therein also evaporates or evaporates, and a dried phase of the substance or mixture of substances, in which the moisture essentially corresponds to the substance or mixture of substances is completely withdrawn. In other words: the drying of a suspension or solution that contains a solid includes increasing the solid concentration by evaporation and / or evaporation of the Moisture in the suspension or solution, as a result of which the solid remains with a residual moisture or dissolved in the remaining liquid as a concentrated solution or suspension. In the borderline case of the complete drying of a suspension or solution that contains a solid, essentially the solid remains without residual moisture or only with a very low residual moisture. If in the following the term drying or drying. is used, it describes not only the moisture content of the end product as "dry" but also the preceding phases of concentration in which a substantial proportion of

There is moisture in the substance or mixture of substances. The suspensions and solutions provided for drying can be very diverse

be solid-containing liquids that are used, for example, in the chemical industry, the basic and production goods industry or the food industry. For example, suspended ceramics, pigments or polymers, mineral sludges such as bentonite sludge, industrial wastewater or even salt solutions or fermentation concentrates are suitable for drying by the device according to the invention.

The electrically conductive properties of the rotatably mounted cylinder make it possible to induce an electrical voltage in the body of the cylinder under the influence of a magnetic field that changes over time. The induced voltage leads to a closed current flow, which is known as "eddy current". According to Jöule's law, this causes heating in the body of the cylinder. The heating resulting from an eddy current is called inductive heating. The heated cylinder ultimately leads to this that a suspension or solution absorbed on the surface dries by heat transfer according to the principle of contact drying. After complete evaporation of the

Moisture contained in suspension or solution, the dried solid remains as dry material on the cylinder surface. If drying is ended earlier, a concentrated substance or mixture of substances remains. The entry of the eddy current into the body of the cylinder is caused by the generated magnetic field of an inductor, which changes over time. In order to generate the magnetic field, an alternating voltage can be applied to the inductor, for example. The applied alternating voltage - determined by its frequency, amplitude, etc. - influences the generated magnetic field and thus the induced inductive heating. Furthermore, the eddy current induced in the cylinder body is determined by the electrical conductivity and the magnetic permeability of the cylinder body. A higher electrical conductivity and / or magnetic permeability and / or a higher frequency of the alternating voltage applied to the inductor result in a lower penetration depth of the induced eddy currents in the cylinder body, so that the inductive heating is effected on the surface or on the surface facing the inductor.

Compared to steam heating, inductive heating has the advantage that a less massive and therefore thinner and more weight-reduced design of the dryer can be used with the same heat output. This is because it is neither a cavity nor special

Requirements regarding the tightness or pressure resistance to the

Cylinder components must be provided. Due to the heating in the cylinder body and in particular in the surface itself, a higher effective power and improved temperature control can also be achieved, since the heat energy required for drying is neither transferred from the outside via the surface of the component, e.g. Radiation or convective, i.e.

Heat flow and transfer, or conductive heat input, i.e. Heat conduction, still has to be transferred from the inside by means of a heat transfer medium. The device according to the invention can also offer the possibility of special

Take product properties of temperature-sensitive products into consideration. So are

Surface temperatures of the cylinders below 100 ° C can be achieved, which means that the

solution according to the invention also and in particular for e.g. Products from the food industry, temperature sensitive organic pigments, alginates, yeasts, resins etc. can be used. can. The device according to the invention can also open up the possibility of achieving significantly higher surface temperatures or thermal outputs on which the

solid-containing liquids dry than currently through the use of steam-driven dryer solutions due to the limitation of the pressure due to the strength limits of the

Pressure vessel component is possible.

The rotatably mounted cylinder is particularly preferably designed as a rotatably mounted disc. A disk is a geometric body in the shape of a cylinder with a radius greater than its height. This has the advantage that, in comparison to a rotatably mounted cylinder, a more compact dryer solution is made possible with the same surface intended for receiving the liquid to be dried.

In a further preferred embodiment of the present invention, the rotatably mounted cylinder is arranged horizontally in the direction of its greatest extent. Its base and / or top surface point essentially in the horizontal direction. For the particularly preferred case that the rotatably mounted cylinder is a rotatably mounted disc, the Disc arranged vertically in the direction of its greatest extent. Their extended side surfaces point essentially in the horizontal direction. This allows excess liquid, ie the solid-containing suspension or solution, to drip off the surface, so that a substantially uniformly thin film of the liquid can form on the surface of the rotatably mounted cylinder. Both the rotatably mounted cylinder and the rotatably mounted disk can also have a different orientation.

A preferred embodiment of the present invention can expediently comprise further rotatably mounted cylinders with electrically conductive properties, each having a surface for receiving the suspension or solution, and / or inductors, the plurality of inductors being configured to the rotatably mounted cylinder or the plurality to inductively heat rotatably mounted cylinders. One or more inductors are particularly preferably assigned for the inductive heating of a rotatably mounted cylinder. Particularly preferably, the inductive heating also has the effect that the rotatably mounted cylinder is heated at least on the surface. It is also expedient if the inductive heating further has the effect that the rotatably mounted cylinder is heated essentially over the surface. The advantage of heating the rotatably mounted disk at least or even substantially and thus deliberately superficially lies in the fact that the thermal power introduced into the disk reaches the contact surface of the suspension or solution that has been taken up and, in the case of an im

Substantial surface heating is not hindered by the thermal resistances characteristic of each material. This can ensure that a

Heat transfer into the heated pane takes place directly at the location of the applied suspension or solution, so that this in turn occurs on the pane surface according to the principle of

Contact drying dries.

The inductor is advantageously arranged at a distance from the surface of the rotatably mounted cylinder. As a result, the cylinder surface is released for receiving the suspension or solution and is not covered by the inductor. The drying capacity of the cylinder can thus be maximized. In addition, the inductor is expediently arranged in a stationary manner relative to the rotatably mounted cylinder, so that the inductor does not move with a rotating cylinder. This is advantageous in that a larger area of the cylinder body is heated than for an inductor that is arranged on the cylinder and therefore rotates with it. This enables a compact design that is essentially limited to the expansion of the cylinder. The rotatably mounted cylinder particularly preferably has an axis of rotation on which it is rotatably mounted. The inductor is designed to surround the cylinder on two opposite sides of the surface along and / or orthogonally to the axis of rotation. The advantage is that the suspension or solution received on the surface of the rotatably mounted cylinder dries on the two opposite sides of the surface along and / or orthogonally to the axis of rotation. This makes it possible to use a single inductor to heat the outer surface and the side surfaces of the cylinder along the axis of rotation and thus to dry the solid-containing liquid on these surfaces in an energy-efficient and material-saving manner.

The method of inductive cross-field heating is preferably chosen. However, other methods such as inductive longitudinal field heating are also possible.

The rotatably mounted cylinder particularly preferably has an axis of rotation, the inductor being arranged coaxially to the axis of rotation. This has the advantage that after a corresponding rotation of the cylinder, its surface is heated in the form of an annular surface on which the

absorbed suspension or solution dries. With a single inductor, a larger area of the cylinder surface can be heated than for an inductor that is arranged axially. The rotatably mounted cylinder expediently has a heterogeneous electrical conductivity and / or magnetic permeability such that the rotatably mounted cylinder is heated to a greater extent inductively on the surface. In contrast to a body with a homogeneous electrical conductivity and magnetic permeability, this has the advantage that a larger proportion of the thermal energy is induced in the peripheral area of the cylinder surface and thus closer to the contact surface that absorbs the suspension or solution. This enables more energy-efficient drying to be achieved.

Preferably, instead of a single material, the rotatably mounted cylinder can also be constructed, for example in the form of a "sandwich" construction, from several layers of different materials, for example normal steel / structural steel, ferritic stainless steel, copper, graphite or others, in such a way that both the concerns of the best possible efficiency of the inductive heat input, as well as the concerns of optimal heat conduction and heat storage, a simpler construction and also the concerns of a possible corrosive or abrasive effect of the substances to be dried are taken into account. Particularly preferably, the device according to the invention further comprises a voltage source which is designed to apply an electrical alternating voltage to the inductor in a controllable manner in order to constantly heat the rotatably mounted cylinder. A constant drying process is achieved by constant heating, so that the suspension or solution is always dried within the same time or, in the case of a cylinder rotating at constant rotational speed, after the same cylinder rotation.

Depending on the requirements of the drying process and its possibly required regulation, as well as depending on the requirements of the product according to its possible temperature sensitivity, several inductors can be distributed along the circumference of the cylinder for a specially graded heat input in each area of the rotatably mounted cylinder. Special inductor formats can be used so that the cylinder surface is optimally covered. The rotatably mounted cylinder expediently has a side surface which is formed along the direction of the greatest extent of the rotatably mounted cylinder, the inductor comprising an elongated electrical conductor which is wound along the direction of the greatest extent of the rotatably mounted cylinder such that the coiled elongated electrical conductor covers at least half of the side surface. This allows a large part of the side surface of the rotatably mounted cylinder to be heated inductively, whereby the

The drying process is accelerated.

The device according to the invention particularly preferably comprises further inductors which are designed to inductively heat the cylinder, the one and the further inductors being wound in a circular, spiral or triangular shape, and the one and the further inductors along the cylinder circumference and the Direction of the greatest extent of the rotatably mounted cylinder are arranged distributed. Depending on the requirements of the drying process, an arrangement of inductors distributed along the circumference of the cylinder enables a particularly finely graduated heat input to be implemented in each area of the cylinder.

The inductor expediently comprises an elongated electrical conductor which, in this way, along the direction of the greatest extent of the rotatably mounted cylinder and the

Is wound cylinder circumference that the wound elongated electrical conductor along the cylinder circumference has a varying winding density. The winding of the inductor is preferably designed in such a way that the elongated electrical conductor is adjacent to one another Has sections. As a result, a differentiated or graduated heat input along the cylinder circumference can be induced into the rotatably mounted cylinder with the aid of an inductor, which is adapted to the respective drying task. In addition, one-piece designs of the inductor or inductors enable simpler designs of the electrical devices for supplying the inductor or inductors (resonant circuits, generators).

The regulation and monitoring of the temperature of the rotatably mounted cylinder is advantageously carried out by measuring the surface temperature of the cylinder, e.g. by a non-contact infrared probe. The signal obtained is used in the drying process to influence the heat input through electrical power control of the device / system: In addition, the inductive heat input can be controlled by measuring the resulting product temperature and / or the dry material moisture.

The inductor is particularly preferably tubular in order to be able to pass through it

Receive coolant, thereby cooling the inductor. This is particularly advantageous because it allows the inductor to operate even for high power levels

AC voltage or for high ambient temperatures is guaranteed.

The device according to the invention expediently comprises a cooling system which is designed to supply and discharge the coolant to the inductor. By supplying and discharging the coolant, it can be ensured that the heat generated during the operation of the inductor is transferred to the supplied coolant and is then discharged. This gives the inductor a stable operating temperature and prevents operational failures due to overheating.

In order to allow the heat generated in the inductor to be cooled, the inductors are made of tubular metal, e.g. made of copper. For cooling, water from e.g. 20 ° C flow temperature. The water in the inductor is thereby caused to e.g. 30 ° C and then cooled again in a recooler to the flow temperature of 20 ° C.

For the construction of the inductor, copper pipes with an outside diameter of, for example, 10 mm and a wall thickness of, for example, 1 mm are preferably used. The pipelines can also have other cross-sections, for example square, for good processability and, for example, to achieve high rigidity. Significantly higher amounts are particularly preferred for dissipating the heat from the inductor

Temperatures of e.g. 80 ° C to 95 ° C provided. This can either be achieved by using significantly smaller amounts of water for cooling, or a cooling water circuit with a high water flow at a higher overall temperature level with a cooling water inlet temperature of approx. 80 ° C and a cooling water return temperature of approx. 95 ° C is used. The resulting cooling water of elevated temperature is e.g. by means of

Pipelines passed through a liquid reservoir for the liquid to be dried, which is arranged in front of the supply of the liquid to the dryer device according to the invention. The pipeline in the liquid reservoir, through which the heated cooling water flows, is designed as a heat exchanger with the largest possible surface area, so that the cooling water is able to transfer its heat to the liquid to be dried in the liquid reservoir. The heat dissipated by the cooling water from the inductors is thus recovered and used to preheat the liquid to be dried. The device according to the invention particularly preferably comprises an application device which is designed to apply the suspension or solution to the surface of the rotatably mounted cylinder, in particular to the side surface (s) along the greatest direction of extent. The application device enables the process of application to be automated due to its ability to apply the liquid to be dried mechanically to the surface of the cylinder. It also contributes to the fact that roughly the same amount of liquid is applied to the rotatably mounted cylinder over time, so that there is a high level of process reliability during drying.

The device according to the invention expediently comprises a detachment device which is designed to detach the remaining solid material from the surface of the rotatably mounted cylinder, in particular from the side surface (s) along the greatest extension direction. As a result, the cylinder surface is released again after the absorbed suspension or solution has dried, so that the released surface can absorb further liquid containing solids. Thus, the drying process is able to

continuously produce dry goods. That according to the invention is particularly preferred

Removal device a knife, which scrapes the dry material from the surface of the rotatably mounted cylinder.

Since the rotatably mounted cylinder (s) have a heat storage capacity corresponding to the materials used, the area of the cylinder immediately in front of the position of the detaching device for detaching the dried solids from the Cylinder surface form a decaying temperature profile, which depends on the residual moisture of the solid. The invention thus proves to be advantageous in particular for temperature-sensitive goods compared to the previously known heating by saturated steam, in which the roller or disk temperature is particularly in the areas of decreasing solid moisture. still rises and approaches the saturated steam temperature of the heating steam.

In order to avoid contamination of the electrically conductive parts of the inductors or to protect the electrically conductive parts, the inductors are preferred in a

Embodiment provided with a non-conductive and non-magnetic coating or introduced into a housing made of a non-conductive material, which allows the electromagnetic waves to pass through unhindered and which also does not heat itself during operation. Glass or a suitable plastic can be used as materials for such housings. The use of a resin, e.g. a synthetic resin is possible, which offers the advantage that the inductors can be cast firmly into the synthetic resin during the manufacturing process. Synthetic resins that can be used are known from the manufacture of transformers, in which the windings of the coils are often also cast in. This achieves a particularly tight and permanent sealing of the inductors.

In a further preferred embodiment of the present invention, the inductor, preferably also further inductors, is arranged integrated within the rotatably mounted cylinder. The inductor or inductors are arranged, for example, in a cavity of the rotatably mounted cylinder and enclosed by the cylinder. In this embodiment, the inductor or inductors are also set in rotation with the cylinder via a common shaft. The electrical supply to the inductor (s) is provided via a hub,

for example via a brush system that is able to transmit the required voltage. Such an arrangement is advantageous in order to protect the inductor from corrosion, wear or contamination by the solid-containing liquid. From e.g. For reasons of hygiene, such an arrangement is also advantageous in order to keep the liquid to be dried free of contamination. An integrated arrangement of the inductor also makes it easier to homogeneously heat the body of the cylinder inductively. So the inductor can e.g. fill the entire cavity along the direction of extension of the cylinder to heat the surface along the direction of extension of the cylinder.

The rotatably mounted cylinder particularly preferably has a shaft, the shaft being drivable via a direct coupling. Compared to steam-heated roller or Disk dryer, a much simpler method of driving the rotation of the roller or disk can be used because the steam heating is required

Steam connections and steam supply pipes are not required. For the device according to the invention can gear motors with modern

Direct couplings so-called slip-on geared motors are used.

Slip-on geared motors are particularly robust and easy to change in the event of damage thanks to the direct coupling. This results in a reduced maintenance and

Maintenance effort than for gear motors that are coupled to the support shaft of steam-powered dryer solutions.

The device according to the invention particularly preferably has a total of four, six, eight, ten or twelve or even more rotatably mounted cylinders or disks. The rotatably mounted cylinders or disks can e.g. be arranged centrally on an axis of rotation or support shaft or several axes of rotation or support shafts distributed at a distance.

When using several individual inductors per cylinder, these can be controlled individually and their supply voltages can be regulated with regard to frequency, etc. so that individual areas of the cylinder on which the liquid to be dried or the dried solid with a certain residual moisture is located experience gradual, different heat input and thus obtain different temperatures in a targeted manner. In particular, in the areas in which the material to be dried is still present on the cylinder as a liquid, a significantly higher heat input can occur because moist goods are cooled by the evaporation of the water or solvent and the risk of overheating both the cylinder and the cylinder of the goods during drying is thus low. In the areas of the rotating cylinder, e.g. shortly before the area of the detachment device for detaching the dried solids, in which the material is already largely dry and only a small amount of residual moisture needs to be removed until the target humidity is reached, the individual regulation of the output of individual inductors can be achieved with significantly less

Heat input and thus work with lower temperatures, which prevents temperature-sensitive goods from overheating, caking and being damaged during drying. In order to have good corrosion resistance against the to To achieve drying liquid and abrasion resistance against mechanical wear, the cylinders can be provided with a coating that is resistant to corrosion and wear. These coatings can be of a metallic nature, for example made of alloys

Hard metals, as well as non-metallic nature, e.g. Ceramic, be. Non-metallic

Coatings have the effect that the heat generated by induction is carried deeper into the component or cylinder, whereas with electrically conductive materials the

Coatings a significant proportion of the heat is already induced in the coatings.

In a further embodiment of the present invention, the cylinder is designed as a roller (i.e. also in the form of an open tube), the outer surface of the cylinder being larger than the two (possibly existing) side surfaces combined. With such a ratio of the surfaces of the cylinder, the drying process is implemented on the outer surface. In this embodiment of the present invention, it makes sense that the inductor or inductors are provided or are arranged in the interior of the cylinder. Due to the electrical conductivity of the outer surface of the cylinder, it is useful to make it from a solid

Manufacture material, The other properties can essentially be adopted from the other embodiments as described above.

In a further embodiment of the present invention, the roller is not formed from an essentially rigid and non-deformable cylinder or tube, but from a flexible band material with electrically conductive properties, which is an endless band or

Conveyor belt can be designed, which is deflected via rollers arranged at the ends of the circulating belt. This arrangement according to the invention allows the inductors to be arranged essentially flat under or above the belt material and thus to heat a flat surface evenly.

According to a further aspect, the invention relates to a device for the industrial drying of a suspension or solution which contains a solid, comprising: a cylindrical tube with electrically conductive properties, which has an inner jacket surface for receiving the suspension or solution; an inductor which is designed to inductively heat the cylindrical tube, the inductive heating causing the suspension or solution received on the inner circumferential surface of the cylindrical tube to dry and the solids to remain.

In a preferred embodiment of the present invention, the cylindrical tube is in Direction of its greatest extent arranged vertically. Its openings on the end faces essentially point in the vertical direction. As a result, excess liquid, ie the suspension or solution containing solids, can run off the inner jacket surface, so that an essentially uniformly thin film of the liquid can form on the inner jacket surface of the cylindrical tube. The cylindrical tube can also have a different orientation.

The inductor, which is designed to inductively heat the cylindrical tube, is preferably arranged outside the cylindrical tube. The method of inductive longitudinal field heating is preferably used. The inductor or inductors can be arranged so that they surround the tube from the outside.

According to a further aspect, the invention relates to a device for industrial drying of a suspension or solution that contains a solid, comprising: a conveyor belt with electrically conductive properties that has a surface for receiving the suspension or

Has solution; an inductor which is designed to inductively heat the surface, the inductive heating causing the suspension or solution received on the surface of the conveyor belt to dry and the solid to remain. The conveyor belt is preferably arranged horizontally in the direction of its greatest extent. The conveyor belt is also preferably inclined about its greatest direction of extent in the vertical direction. This allows excess liquid, i. the solid-containing suspension or solution, run off the surface, so that a substantially uniformly thin film of the liquid can form on the surface of the conveyor belt. The conveyor belt can also have a different orientation.

According to a further aspect, the invention relates to a device package for the industrial drying of a suspension or solution which contains a solid. The device package according to the invention comprises a plurality of rotatably mounted disks with electrically conductive properties, each rotatably mounted disk having a surface for receiving the suspension or solution, the rotatably mounted disks being arranged spaced apart from one another along an axis of rotation. In addition, this includes

inventive device package inductors that are designed to give them

to inductively heat associated rotatably mounted disks, the inductors being arranged between the plurality of rotatably mounted Sqheiben. This causes the inductive Heating that received on the surfaces of the rotatably mounted discs

The suspension or solution dries and the solid remains.

The plurality of rotatably mounted disks is preferably arranged in such a way that the rotatably mounted disks are each aligned vertically in the direction of their greatest extent. Their extended side surfaces each point essentially horizontally

Direction.

According to a further aspect, the invention relates to a system for the industrial drying of a suspension or solution which contains a solid. The system according to the invention comprises the device according to the invention, wherein the inductor is tubular in order to receive a coolant through it, whereby the inductor is cooled, and wherein the device comprises a cooling system which is designed to supply and remove the coolant from the inductor . The system also includes a heat exchanger, wherein the cooling system is connected to the heat exchanger to cool the coolant and the

To heat suspension or solution. Particularly preferably, the stream of the suspension or solution to be dried is fed into the heat exchanger before it is fed to the device according to the invention for drying, the coolant being conducted in a separate circuit as countercurrent and preheating the suspension or solution to be dried by heat transfer. The use of the heat exchanger reduces the heat loss of the system and increases the overall drying efficiency.

Advantages of the devices according to the invention or the system and its embodiments as well as further useful embodiments can be found in the first-mentioned device according to the invention, as described above.

According to a further aspect, the invention relates to a method for industrial drying of a suspension or solution, which is described below.

The method according to the invention for the industrial drying of a suspension or solution which contains a solid comprises the following method steps:

- Taking up the suspension or solution on a surface of a rotatably mounted cylinder with electrically conductive properties;

and - Inductive heating of the rotatably mounted cylinder in order to dry the suspension or solution taken up so that the solid remains.

Particularly preferably, the inductive heating takes place at least over the surface in the rotatably mounted cylinder.

The method according to the invention expediently further comprises the following steps:

- Application of the suspension or solution to the surface of the rotatably mounted

Cylinder; and

Detachment of the remaining solid.

Advantages of the method according to the invention and its embodiments as well as further useful embodiments are the device according to the invention, as above

described, to be taken accordingly.

The invention enables the direct use of electrical energy and its use for heating the cylinder for drying a solid-containing liquid with high

Efficiency, which means that the provision of heating steam from a complex steam network and the complex piping and fittings can be dispensed with. Furthermore, instead of the rollers or disks designed as hollow pressure vessels with the need to prove the compressive strength and imperative tightness of the entire components, including the necessary testing and acceptance by an officially certified body, a simple solid design of the roller or disk made of a conductive metallic material can be selected which significantly simplifies the production of a single roller or disk or a corresponding package. The use of fossil fuels to generate heating steam with the well-known, sometimes low levels of efficiency due to waste heat losses will also become unnecessary, which will be of increasing importance, especially in the future, the more sustainably generated electrical energy from renewable energy sources (solar, hydropower, wind) is available becomes. The invention can thus make a contribution to the avoidance or reduction of C0 ₂ emissions.

Preferred embodiments of the present inventions are explained in more detail with reference to the following drawings. It shows:

Fig. 1 is a perspective view of a first embodiment of the invention

Contraption;

2 shows a side view of a first embodiment of the device according to the invention;

3 shows a top view of a first embodiment of the device according to the invention; 4 is a front view of a first embodiment of the invention

Fixture package;

Fig. 5 is a frontal view of a second embodiment of the invention

Device packages;

6 is a front view of a third embodiment of the invention

Device packages;

7 is a side view of a second embodiment of FIG _. device according to the invention;

8 shows a side view of a third embodiment of the device according to the invention;

9 shows a side view of a fourth embodiment of the device according to the invention; 10 is a side view of a fifth embodiment of the device according to the invention;

1 1 is a schematic view of an embodiment of the system according to the invention;

Figures 1 to 3 show different views of a first embodiment of the

Device 100 according to the invention for the industrial drying of a suspension or solution. Device 100 has a rotatably mounted disk 110 with electrically conductive properties, the disk 110 being circular, and an inductor 120. The disc 110 is provided with a centrally arranged opening in order to push it onto a shaft and fasten it. The disk preferably contains 110 steel, ferritic stainless steel, copper and / or graphite. However, other electrically conductive materials are also conceivable. The diameter the disk 1 10 is preferably 500 to 1500 mm. It is particularly preferred that

Disc thickness 5 to 15 mm. The inductor 120 comprises an elongated conductor, e.g. a wire. In order to prevent contamination of the electrically conductive parts of the inductor 120, a non-conductive and non-magnetic coating can be applied. A housing (not shown) made of a non-conductive or magnetizable material that surrounds the inductor 120 is also conceivable. Suitable materials for protecting the inductor 120 are

for example glass, plastics or synthetic resins. Furthermore, the inductor 120 is arranged to be wound around the disk 110. The wound arrangement can surround the pane surface, preferably half the pane surface. In the embodiment of Figure 1, the winding of the inductor 120 begins at the level of the horizontal disk diameter and leads to the upper edge of the disk 110. The contactable end sections of the inductor are spaced on one end face of the disk 110. The distance between the individual

wound conductor layers of the inductor 120 can be between 10 and 50 mm. In order to keep the central opening of the disk 110 free, the elongated conductor is circular

Sections which are concentrically arranged over the opening. The radii of the circular sections increase with increasing distance from the central opening of the disk 110.

There is a gap between the disk surface and the elongated conductor, so that the rotatably mounted disk .1 10 is freely movable and can be rotated. The smallest possible distance between the inductor 120 and the rotatably mounted disk 110 is advantageous, since this determines the efficiency of the induced heat input. The distance between inductor 120 and disk 110 is preferably 3 to 10 mm. The arrangement of the inductor 120 wound around the disk 110 is selected so that when an alternating voltage is applied to the inductor 120, an eddy current is induced in the body of the disk 110. The magnetic field generated by inductor 120 is essentially in the direction of the disk surface. aligned. Because of the Joule heat generated as a result of the induced eddy current, the pane 110 is heated. A solid-containing liquid applied to the surface of the pane 110 would thus dry according to the principle of contact drying. The disk 1 10 also has a certain heat capacity, which is determined by the selected material or the composite materials. That area of the disk 110 that is wrapped by the inductor 120 is directly inductively heated by the inductor 120 and thereby receives the necessary operating temperature around that on the surface of the disk 110

to dry absorbed solid-containing liquid. The remaining area of the disk 110, however, has a lower temperature. How the temperature profile is set in the stretch area of the pane 110 that is directly inductively heated and in the area of the pane 110 that is not directly inductively heated depends on the material and its heat capacity and / or Thermal conductivity and the speed of rotation of the disk 1 10.

Figures 4 to 6 show different embodiments of the device package 200 for industrial drying of a suspension or solution in a front view. In the

In embodiments, the device packages 200 according to the invention consist of four disks 210 which are fastened centrally on a common support shaft and are arranged parallel to one another. The individual disks 210 are designed, for example, as in the embodiment of FIGS. 1 to 3. FIG. 4 shows an embodiment in which two inductors 220 are assigned to each disk 210. The inductors 220 are also arranged such that they can each inductively heat an individual disk 210 in the area of one of their side surfaces. The side surfaces lie along the direction of extension of the disks 210. FIG. 5 shows one

Embodiment in which an inductor 221 is arranged between two disks 210. The inductors 221 inductively heat the side surfaces of the disks 210, which are arranged adjacent to the inductors 221. The disks 210 located on the outside in this device package according to the invention are also inductively heated on their outer side surfaces with an inductor 220. Figure 6 shows a further embodiment of the

Device package according to the invention. One inductor 222 is assigned to each disk 210. The inductors 222 are such that they inductively heat the disk 210 assigned to them on the opposite side surfaces along the axis of rotation or support shaft 230. The inductors 222 can be e.g. each extend from one side surface, over the edge of the pane and up to the opposite side surface.

FIGS. 7 to 10 show further embodiments of the device 300, 301, 302, 303 according to the invention in a side view. Different configurations for the arrangement of the inductor or inductors are shown. Depending on the requirements placed on the drying process, a plurality of inductors can be distributed along the circumference of the disk 310 for a gradual introduction of heat into each area of an individual disk 310. In FIG. 7, inductor 320 is arranged adjacent to and at a distance from a side surface of disk 310. In addition, the inductor 320 comprises an elongated conductor which is wound along the direction of extent of the disk 310 in such a way that the inductor 320 wound along the direction of extent of the disk 310 covers one side surface of the disk 310.

Preferably, the inductor 320 has two circular sections coaxial about the

Rotation axis of the disc 310 are arranged. The radius of the outer circular section is preferably approximately the same size as the radius of the disk 310. This embodiment of the invention also has a detachment device 340 and an application device 350. The Application device 350 is designed to apply the solid-containing liquid to disk 310. The detachment device 340, on the other hand, is designed to detach the dry material from the surface of the disc 310, for example by means of a knife resting on the surface. The application device 350 and the detachment device 340 are arranged, for example, in that area adjacent to the disk 310 which is not covered by the inductor 320. In FIGS. 8 and 9, arrangements with several, for example four, individual inductors 321 are shown. When using several individual inductors 321, these can be individually controlled. Both the supply voltage of the inductors and their frequency can be regulated so that the individual areas of the window on which the to be dried

Liquid containing solids, or even the dried-on solid with a certain residual moisture, experience a graduated, different heat input and thus receive different temperatures in a targeted manner. FIG. 8 shows an embodiment of the device 301 according to the invention, the inductors 321 each being wound from an elongated conductor in a triangular manner along the direction of extension of the slide 310. The inductors 321 are arranged coaxially along the circumference. The inductors 321 can also be aligned such that a corner of the triangular winding of each inductor 321 points to the axis of rotation or the support shaft. The inductors 321 on one of the side surfaces of the disk 310 can be located within the disk radius or protrude beyond it. FIG. 9 shows a similar arrangement of inductors 322 as in FIG

Embodiment of Figure 8. In the embodiment of Figure 9, inductors 322 are circularly or spirally wound from an elongated conductor. FIG. 10 shows an embodiment of the device 303 according to the invention, in which the inductor 323 is wound from an elongated conductor and has a varying winding density along the circumference of the disk. The winding density can be determined by the distance between adjacent sections of the elongated conductor. A higher winding density means a smaller distance between the adjacent sections of the elongated conductor and vice versa. The winding density can be different in zones. For example, it can be highest in the area of the application device and lowest in the area of the detachment device. Such a configuration is advantageous because the moisture content of the applied solid-containing liquid is highest immediately after it is applied to the surface of the disk 310 and a large amount of moisture can evaporate. In the area of the detachment device, the moisture content of the solid-containing liquid is significantly lower, so that a reduced heat input into this area of the pane 310 is sufficient to cause the residual moisture to evaporate. For the temperature-sensitive solids, it can also be important that they do not exceed a certain temperature in order not to be damaged. Figure 11 shows a schematic view of an embodiment of the system according to the invention. The system shown here comprises a rotatably mounted disk 310, an inductor 323, a detachment device 340 and an application device 350. These components of the system have already been explained in more detail above. Furthermore, the system comprises a liquid feed which opens into a liquid tank 370 in which the liquid containing solids intended for drying collects. The application device 350 is connected to the liquid tank 370 in order to convey the solid-containing liquid from the tank onto the surface of the disk 310 and apply it. Excess liquid drips off the surface of the pane and runs back into the liquid tank. Furthermore, the inductor 323 is coupled to a cooling circuit. Coolant is supplied to the inductor 323, which is, for example, tubular, to the

To receive coolant through it. Under normal operating conditions, the inductor 323 heats up, the supplied coolant carries out the heat from the inductor 323

Heat transfer to the coolant. The heated coolant can then be fed into the heat exchanger 360, the liquid feed being preheated as a countercurrent through the heated coolant before it reaches the liquid tank 370.

As a result, heat from the coolant, which it previously removed from the inductor 323, can be recovered by preheating the liquid to be dried. The converter 380 and the resonant circuit 385 serve to regulate the alternating voltage applied to the inductor 323. Furthermore, the resonant circuit 385 is used within the system to supply power to the

Inductor 323. The vapors in the form of the moisture evaporated from the liquid to be dried are discharged with the aid of the vent 390.

With the described embodiments of the device according to the invention, in

Drying process a water evaporation rate of approx. 350 kg / h can be realized. The liquid to be dried is, for example, a mineral suspension with a solids content of 50% dry matter. The required heating power is provided by inductive heating with an output of 240 kW. The inductors are supplied by a generator with an output of 280 kW. The process produces a product quantity of 437 kg / h with a residual moisture of 10% water. The product takes on a temperature of approx. 60 ° C as it dries. List of reference symbols

100, 300, 301, 302, 303 Device for industrial drying

a suspension or solution

110, 210, 310 cylinder / disc

120, 220, 221, 222, inductor

320, 321, 322, 323

200, 201, 202 Device package for industrial drying of a suspension or solution

230 support shaft

340 release device

350 orders scheduling

360 heat exchangers

370 liquid tank

380 converters

385 resonant circuit

390 deduction

1000 system for industrial drying

a suspension or solution.

Claims

PATENT CLAIMS

1 . Device (100, 300, 301, 302, 303) for industrial drying of a suspension or solution containing a solid, comprising:

- A rotatably mounted cylinder (1 10, 310) with electrically conductive properties, which has a surface for receiving the suspension or solution;

an inductor (120, 320, 321, 322, 323) which is designed to inductively heat the cylinder (1 10, 310),

wherein the inductive heating causes the suspension or solution received on the surface of the rotatably mounted cylinder (1 10, 31 0) to dry and the solid remains.

2. Device (100, 300, 301, 302, 303) with the features according to claim 1, wherein the rotatably mounted cylinder (1 10, 310) is designed as a rotatably mounted disc.

3. Device (100, 300, 301, 302, 303) with the features according to claim 1 or 2, wherein the inductive heating further causes the rotatably mounted cylinder (1 10, 310) to be heated at least on the surface.

4. Device (100, 300, 301, 302, 303) with the features according to one of the preceding claims, wherein the inductor (120, 320, 321, 322, 323) spaced from the surface of the rotatably mounted cylinder (1 10, 310) is arranged.

5. Device (100, 300, 301, 302, 303) with the features according to one of the preceding claims, wherein the rotatably mounted cylinder (1 1 0, 310) has an axis of rotation on which it is rotatably mounted, and wherein the inductor (120, 320, 321, 322, 323) is designed to surround the cylinder (1 10, 310) on two opposite sides of the surface along and / or orthogonally to the axis of rotation.

6. Device (100, 300, 301, 302, 303) with the features according to one of the preceding claims, wherein the rotatably mounted cylinder (1 10, 310) has an axis of rotation, and wherein the inductor (120, 320, 321, 322 , 323) is arranged coaxially to the axis of rotation.

7. Device (100, 300, 301, 302, 303) with the features according to one of the preceding claims, wherein the rotatably mounted cylinder (1 10, 310) has a heterogeneous electrical conductivity and / or magnetic permeability such that the rotatably mounted Cylinder (1 10, 310) is superficially heated more inductively.

8. The device (100, 300, 301, 302, 303) with the features according to one of the preceding claims, further comprising a voltage source, which to this. is designed to apply an electrical alternating voltage to the inductor (120, 320, 321, 322, 323) in a controllable manner in order to constantly heat the rotatably mounted cylinder (110, 310).

9. Device (100, 300, 301, 302, 303) having the features according to one of the preceding claims, wherein the inductor (120, 320, 321, 322, 323) is tubular in order to receive a coolant through it, whereby the inductor (120, 320, 321, 322, 323) is cooled.

10. Device (100, 300, 301, 302, 303) with the features according to claims 1 to 9, wherein the rotatably mounted cylinder (1 10, 310) has a side surface which extends along the direction of the greatest extent of the rotatably mounted Cylinder (110, 310), and wherein the inductor (120, 320, 321, 322, 323) comprises an elongated electrical conductor which is wound along the direction of the greatest extent of the rotatably mounted cylinder (110, 310), that the wound elongated electrical conductor covers at least half of the side surface.

1 1. Device (100, 300, 301, 302, 303) having the features according to claims 1 to 9, further comprising further inductors which are designed to inductively heat the rotatably mounted cylinder (1 10, 310), wherein the one and the further inductors are wound circular, spiral or triangular, and wherein the one and the further inductors are arranged distributed along the cylinder circumference and the direction of the greatest extension of the rotatably mounted cylinder (1 10, 310).

12. Device (100, 300, 301, 302, 303) having the features according to claims 1 to 9, wherein the inductor (120, 320, 321, 322, 323) comprises an elongated electrical conductor, which along the direction of the largest extension of the rotatably mounted cylinder (1 10, 310) and the cylinder circumference is wound, that the wound elongated electrical conductor has a varying winding density along the cylinder circumference.

13. Device (100, 300, 301, 302, 303) with the features according to one of the preceding claims, wherein the inductor (120, 320, 321, 322, 323) is arranged integrated within the rotatably mounted cylinder (1 10, 310) is.

14. Device (100, 300, 301, 302, 303) with the features according to one of the preceding claims, wherein the rotatably mounted cylinder (1 10, 310) has a shaft, and wherein the shaft can be driven via a direct coupling.

15. Device (100, 300, 301, 302, 303) with the features according to one of the preceding

Claims, further comprising an application device (350) which is designed to apply the suspension or solution to the surface of the rotatably mounted cylinder (1 10, 310).

1 6. Device (100, 300, 301, 302, 303) with the features according to one of the preceding

Claims, further comprising a detachment device (340) which is designed to detach the remaining solid material from the surface of the rotatably mounted cylinder (1 10, 310).

1 7. Device (100, 300, 301, 302; 303) having the features according to claim 9, further comprising a cooling system which is configured to supply the coolant to the inductor (120, 320, 321, 322, 323) and discharge.

1 8. System (1000) for industrial drying of a suspension or solution containing a solid, comprising:

a device having the features according to claim 1 7; and a heat exchanger (360),

wherein the cooling system is connected to the heat exchanger (360) to cool the coolant and to heat the suspension or solution.

19. Apparatus for industrial drying of a suspension or solution containing a solid, comprising:

- A cylindrical tube with electrically conductive properties, which has an inner jacket surface for receiving the suspension or solution; an inductor that is designed to inductively heat the cylindrical tube,

wherein the inductive heating has the effect that the suspension or solution received on the inner surface of the cylindrical tube dries and the solid remains.

20. Apparatus for industrial drying of a suspension or solution containing a solid, comprising:

a conveyor belt with electrically conductive properties, which has a surface for receiving the suspension or solution;

an inductor which is designed to inductively heat the surface zp, the inductive heating having the effect that the suspension or solution received on the surface of the conveyor belt dries and the solid remains.

21. Device package (200, 201, 202) for industrial drying of a suspension or solution containing a solid, comprising:

- A plurality of rotatably mounted disks (210) with electrically conductive properties, each rotatably mounted disk having a surface for receiving the suspension or solution, and wherein the rotatably mounted disks (210) are arranged at a distance from one another along an axis of rotation;

Inductors (220, 221, 222) which are designed to inductively heat the rotatably mounted disks (210) assigned to them,

wherein the inductors (220, 221, 222) are arranged between the plurality of rotatably mounted disks (210), and

wherein the inductive heating has the effect that the suspension or solution received on the surfaces of the rotatably mounted disk dries and the solid remains.

22. A process for the industrial drying of a suspension or solution containing a solid, comprising the following process steps:

- Taking up the suspension or solution on a surface of a rotatably mounted cylinder (1 1 0, 310) with electrically conductive properties;

and

- Inductive heating of the rotatably mounted cylinder (1 10, 310) in order to dry the suspension or solution taken up so that the solid remains.

23. The method with the features according to the preceding claim, wherein the inductive heating takes place at least on the surface in the rotatably mounted cylinder (1 10, 310).

24. The method having the features according to claim 22 or 23, which further comprises the following method steps:

Application of the suspension or solution to the surface of the rotatable

Cylinder (1 10, 310);

and

Removal of the remaining solid.

25. The method with the features according to claims 22 to 24, wherein the rotatably mounted cylinder (1 10, 310) is a rotatably mounted disc.