METHOD OF AND APPARATUS FOR DRYING PRODUCTS WITH A CLOSED GAS STREAM AND A DESICCANT LIQUID; AND PRODUCTS PREPARED THEREBY

Abstract: A method of and apparatus for drying products with a gas stream passing the product to extract moisture therefrom and a contacting device (43) producing at least one desiccant liquid layer (1) in the vicinity of the product (50) to be dried, which liquid layer removes moisture from the gas. The gas stream is bubbled through a substantially horizontal liquid layer or can pass between liquid film conducting elements (58). The desiccant liquid is continuously regenerated in a regenerator (150). By moans of several partial gas streams and a contacting device having more separated liquid film modules, a counter-current type of drying is possible. The product to be dried can be heated to a predetermined temper­ ature by the desiccant liquid through the drying gas stream.

Description: METHOD OF AND APPARATUS FOR DRYING PRODUCTS WITH A CLOSED GAS STREAM AND A DESICCANT LIQUID; AND PRODUCTS PREPARED THEREBY. This invention relates to a method of and an apparatus for drying products with a closed gas stream and with a desiccant (sorption) liquid reducing the moisture content of the gas stream; and to products prepared by said method or apparatus. A well-known method of drying products consists in that the material to be dried is brought into direct contact with some gas, in most oases with air unsaturated with moisture, this way the material gets drier, the gas more and more saturated with moisture. Drying apparatuses in common use at present - especially the ones serving for drying a relatively big amount of produc ts - usually dry with heated air of small relative humidity, which is released into the atmosphere after the drying haB taken place. This open gas stream drying is accompanied by a significant loss of thermal energy, and it is unsatisfactory also because in some cases the products to be dried are heat-sensitive. It can also be disadvantageous beoause of producing air-pollution. It was precisely the heat-sensitivity of special products (medicines, gelatine, foodstuffs, etc.) which made drying with low e.g. ambient or sub-ambient) temperature gas necessary. The small relative humidity of low temperature gas, which is a prerequisite of effective drying of these kinds of products, oan be achieved through demini-shing the absolute humidity of the gas. Therefore it has been auggested e.g. in U.S. Patent No. 5t257,737 that the drying gas should be contacted with solid adsorbents which extract the moisture content of the gas. It has also been suggested e.g. in Austrian Patent No. 317,857 and in Brutish Patent No. 1 152.440 to use desiocant (hygroscopic) liquids (e.g. aqueous solutions of lithium chloride or ethylene glycol) to remove the moisture from a gas. A continuous regeneration of the drying gas in this manner makes a closed gas stream also applicable. The suggested solutions utilising a desiccant liquid cause the liquid to contact with the gas stream in sprayed or pulverized form, and the liquid particles carried away by gas stream are held back by a drip separator. Such a system from the point of view of energetics is theoretically more favourable than the one working with heated air essentially because thermal loss caused by the releasing of the air into the atmosphere is omitted. Still, up till now, closed gas circulation systems have only been used in case of special drying problems, and whenever it was possible with regard to the characteristics of the products to be dried, the open air stream method with heated air was applied. The reason for this is that the traditional type of closed gas circulating driers requires costly investment, the circulation of large amounts of gas is highly energy-consuming, and the desiccant liquid used for regneration is expensive; these factors result in high operating costs. It is the main object of the invention to provide a closed gas stream drier which as far as costs are concerned, is more favourable than the previous closed gas stream driers and is competitive with the known open air stream driers, even in case of a big amount of products to be dried. The invention is based on the following basic ideas; (1) Contact between the gas stream and the desiccant liquid should not be bought about by spraying or pulverisation of the liquid but with the aid of a gas-liquid contacting device placed in the path of the gas stream which a llowes the separ3tion of drying space and regenerating space as used till now to be eliminated. (2) In a closed air stream circulation system the amount of air to be used for a particular purpose is a multiple of that used in an open system. For this reason, the gas contacting device using desiccant liquid and the product to be dried must be placed close to one another and in such a way that the air stream should suffer the least possible alteration in velocity and in direction in the course of the circulation. (3) Drying must be carried out not with low but with such high tempeluture gas stream as is allowed by the character of the product at all, To do this it is expedient to heat the circulated gas stream by the desiccant liquid. (4) When regenerating the desiccant liquid the evaporation heat of the stearn eliminated from the liquid must be recuperated into the liquid to be regenerated sith regard also to the heating needed during the regeneration. (5) The desiccant liquid gas contacting device must be of a structure that can also be modularly arranged, and permit the application of the per se known principle of counter-currentflow for drying of continually moving products. Hence, in one aspect, the present invention comprises a method of drying products with a closed gas stream and a desiccant liquid wherein the following steps are per- formed: introducing tile product to be dried into a drying compartment; continuously circulating a drying gas stream so as to cause it to pass the product to be dried; contacting the drying gas stream with a desiccant liquid to remove moisture from the eas; and regenerating the desiccant liquid by circulating at least a part of it through regenerating means which remove moisture therefrom. The essence of this method consists in producing at least one layer of the desiccant liquid in the vicinity of the product when in the drying compartment, and contacting the drying gas stream with said at least one desiccant liquid layer. Tile applicstioIi of a liquid layer according to the invention is advantageous in several respects. Firstly, it renders unnecessary the drip separator applied in the known systems, while effectively preventing pollution of the gas stream by the liquid-drops, and thus it diminishes the loss of the desiccant liquid also. Secondly, the coefficient of b4le mass transfer between the liquid and the gas is more favourable here than with liquid particles; this allows compact structure accompajiled by 8 smaller pressure drop of the gas stream. Thirdly, it does not demand a contacting space separated from the drying compartment; te liquid layer can be established quite close to the product to be dried. Another advantage is that bringing shout a liquid layer is less delicate an operation than spraying known from the previous solutions, because the danger of a block up is much less, alld so is the need for maintenance. This latter factor is of particular significance ag the gas stream often transports dust and other pollution beside moisture into the desiccant liquid, which block up the holes in the spray nozzles. An advantageous implernentation of the method according to the invention is to produce a substantially horizontal desiccant liquid layer, and bubbling the gas stream through said horizontal liquid layer. By this it is possible to dry bulk goods, for instance transported on a belt conveyor which is conducted under or above the horizontal liquid layer. It is another extremely advantageous implementation of the method wherein at least one desiccant liquid layer is produced by causing the desiccant liquid to flow on liquid film conducting elements, and said contacting is performed by causing said drying gas stream to pass between said liquid film conducting elements. The liquid film conducting elornents oan be applied to form a curtain -like arrangement which seamy for example bound the drying oompartment. Another aspect of the invention consists in a method of drying product wherein the following steps are performed: introducing the product to be dried into a drying @ompartment: continuo@sly circulating a drying gas stream so as to cause it to pass the product to be dried; contacti@g the drying gas stream with a desiocant liquid to ramove moisture from the gas; and regenerating the desiccant liquid by circulating at least a part of it through regenerating means which remove moisture therefrom. The essence of this method consists in bringing about a heat exchange between the desiccant liquid and the product to be dried 90 that the heat is transmitted by the drying gas stream between the desiccant liquid and the product to be dried. It is practical to raise the temperature of the desiccant liquid during regeneration to such a degree that while contacting the desiccant liquid with the drying gas stream the temperature of the gas is raised to a predetermined temperature, preferably over 4O0C, for heating up the product to the degree required, This method provides for the possibility of diminishing the quantity and velocity of the gas o be circulated bec-asa at a higher temperature the quantity of moisture estractable with 1 kg air is increasing, and allows an efficient recuperation of the evaporation heat of the steam evaporat@@ from the desiocant liquid during the regeneration into the desiccant liquid to be regenerated0 A further advantage is the omission of cooling applied in the previous gas-liquid contactors; this results in a simpler construction of the gas-liquid contacting device. According to a particular execution of this method the desiccant liquid is a desiccant solution said regenerating is performed by evaporating the desiccant solution@ and the steam evaporated from the d@siccant @@lution is at least partly condensed by the desiccant solution to be regenerated. This permits highly economic regeneration during which the energy requirement of regeneration can be reduced toa great extent by applying a multi-effect boiling or a multi-stage flash evaporation, Compared to the previous solutions where the evaporation heat of the evaporated steam is used for heating the air which is to predry the product It is an advantage that the steam condensation with a liquid requires a smaller and cheaper device than that working with air, It is practical to boil the desiccant solution to be regenerated with the steam evaporated from the solution during regeneration. Energy requiretnent can be reduced through concentrating the desiccant solution by multi- -effect boiling, and using the incoming solution to be evaporated for condensing nt least partly the steam evaporated during the first or during the last boiling process of the regeneration. Regeneration can be executed by heating the desiccant solution to be regenerated without causingit to boil, with tre steam evaporated from the solution. In this case it is particularly advantageous to regenerate the desiccant solution with a multi-stage flash evaporator. according to a very advantageous implementation of the method of the invention the desiccant solution is to be cooled before regeneration as a function of the tooling own of the desiccant solution during the drying process 0 that the desiccant solution to be regenerated is of a predetermined temperature. The cooling suggested here is vital for tie control of the cycle of tile desiccant solution, and is meant to complement the cooling down which occurs in the desiccant solution on contact with the drying gas stream. The degree of cooling must be a altered for instance according to the season. The ccoling is pieferably done during regeneration. According, to another advantageous implementation of the method,the continuous cilculation of the drying gas stream is performed by conducting the drying gas stream in a path section between the product to be dried and the desiccant liquid so t1iat in said path section the ratio of the laximum and minimum velocity of the drying gas stream is sr!aller than five to one and the alteration of the direction of the drying gas stream is less tiian 30 degree This measure results in a relatively small demand for ventilation power; this is an important point in the econorny of the whole dry procedure, The ventilation power can be further diminished if the drying gas stream is conducted between the product to be dried and the desiccant liquid substantially without any alteration of velocity and direction. It is practical to use air as drying gas and an aqueous solution of calcium chloride as a desiccant solution. The calcium chloride solution is particularly favourable owing to it cheapness. The method according to the invention is applicable not only for eliminating the moisture of water but also @or d@ying materials which contain a different kind of moisture by using an appropriate desiccant liquid. It is possible, for instance, to apply the present method for drying materials containing alcoholic moisture using closed air stream and petrol as desiccant liquid According to a further implementation of the method the drying gas stream consists of at least two parallel partial gas streams: the product to be dried is moved across said partial gas strearns; and each of said partial gas streaks is contacted with a desiccant lielid of specific noncentration and temperature0 In this way the drying program for the product to be dried can be extremely varied. For instance, according to a highly expedient wnplementation of the method, each of said partial gas streams is contacted with a more concentrated desiccant liquid than the desiccant liquid contacting the previous partial gas stream with aspect to the direction of movement of the product to be dried. This results in a counter-current between the product to be dried and the desiccant liquid. The .method according to the invention can be implemented also by producing at least two separated groups of desiccant liquid films of different concentrations placing said @ groups of desiccant liquid films side by side in the way of satu partial gas streams so that each of said gas streams is contacted with its own at least one group of desiccant liquid films. It is an advantageous implementation wherein each of said groups of desiccant liquid films is provided with own lipid circulation; the liquid circulation of the last group with respect to the direction of movement of the product to be dried is fed with the regenerated desiccant liquid coming from said regenerating means the circulation of each preceding group is fed with the overflow of the circulation of the subsequent group; and the overflow of the circulation of the first group is conducted into said regenerating means. In this way counter-current is attained between the desiccant liquid and the product to be dried. It is also possible to move the product to be dried across the partial gas streams and alter the temperature of the product in a prescribed manner through controlling the temperature of the desiccant liquid separately in each individual group of desiccant liquid films. In this manner the drying temperature also in case of continuous drying can easily be programmed for each phase of drying. A further aspect of the invention consists in apparatus for drying products with a closed gas stream and desiccant liquid wherein the apparatus comprises at least one drying compartment for the product to be dried; at least one contacting device for contacting g drying gas stream with a desiccant liquid to remove moisture from the gas gas conducting means for conducting the drying gas stream in a substantially closed path through said drying compartment and said contacting device gas circulating means to cause the drying gas stream to circulate along said closed path regenerating means for removing moisture from the desiccant liquid and liquid circulating means for circulating at least a part of the desiccant liquid through said regenerating means and said contacting device. The apparatus is characterized in that said contacting device includes means for producing at least one layer of the desiccant liquid to be contacted with the drying gas stream; said at least one desiccant liquid layer being located in the vicinity of the product disposed in said drying compartment. In an emzbodiment of the apparatus according to the invention the contacting device comprises a vessel for producing a substantially horizontal desiccant liquid layer, said vessel having on its wall bubbling caps for bubbling the drying gas stream through said liquid layer, said vessel being connected to said liquid circulating means so as to cause the desiccant liquid to flow along said vessel, and said drying compartment is located above or below said vessel, Preferably the drying compartment comprises a device for transporting the product to be dried through said drying compartment, said transporting device having openings for letting through the drying gas stream but not letting the product to be dried drop. Advantageously the transporting device is an endless belt conveyor, and said (blowers) gas circulating means are ventilators/placed side by side along said belt conveyor, According to another embodiment of the apparatus the contacting device comprises liquid film conducting elements being placed so that the drying gas stream is passing between said liquid film conducting elements. A high degree of operational safety and simple structure can be achieved if the contacting device further comprises a receptacle for receiving and holding the incoming desiccant liquid} at least one pile lock to guide in film form the liquid out of said receptacle, liquid distributing means having at least one distributing surface connected to said at least one pile lock and facing downwards, and liquid outlet means, wherein said film conducting elements are connected between said liquid distributing surface and said liquid outlet meaits so that they conduct liquid films from said surface into said outlet means. This embodiment is not very sensitive to the pollution which might get into the desiccant liquid from the drying gas stream. It is practical to arrange the liquid film conducting elements - preferably strips or fibres - into at least one substantially vertical plane. There is an excellent heatand mass-transfer between the desiccant liquid films created on the thin fibres and the drying gas stream. The strips or fibres can be made of a metal resistant to the desiccant liquid or of a plastic material which tolerates the highest possible temperatuie of the desiccant liquid. One possible embodiment of the drying apparatus according to the invention is applicable for products as wood. This embodiment comprises a basement, a shell-roof, and a false roof provided with openings for letting through the drying gas stream an@ Jocated between said basement and said shell-roof, wherein said diving compartment is located between said basement and paid false roof, said (blowers) gas circulating means are ventilators/ placed between said false roof and said shell-roof, and E,J) sail contacting device is placed at said drying compartment so that said at least one vertical plane forced by said 'iJILId film conducting elements in substantially perpendicular to the drying gas stream and extends between said basement and said false roof. In such an errangement the liquid film gas contacting device is placed at a b@@@dary surface or a cross-section of the drying compartment, said surface or cross-section being substantially perpend@cular to the direction of the gas stream. This arrangement ensures only a small pressure dro@ for the gas stream which results in a low energy consumption due to the ventilation. A very advantageous embodiment of the apparatus according tc) the invention is wherein the contacting device consists of at least two liquid film modules placed side by side, sach liquid film module has its own liquid film conducting elements and own liquid circulating device providing a liquid circulrjtion to for; the liquid films on said own conducting elements, and said liquid film modules are provided with a common liquid channel inter connecti@g said liquid circulation devices, said common liquid cha@@@@ being connected to said liquid circulating means. Thus the apparatus has one single regenerating means belonging to it, still each liquid film module gets a desiccant liquid whose activity is different from that of the others. According to a further embodiment the ratio of any two flow sections of said gas conducting means between said drying compartment and said contacting device is between 0.2 and 5; and said contacting device is located at said drying compartment so that the drying gas stream flows between the product to be dried and said contacting device with a directional change of less than 30 degrees. It is very advantageous if said flow cross section ratio is between 0.5 and 2, and said directional change is substantially zero degree, and the distance between said drying compartment and said contacting device is less than the hydraulic diameter of said gas-conducting means between them. According to a highly advantageous embodiment of the apparatus the desiccant solution regenerating means contain a multiweffect evaporator or a multi-stage flash evaporator. it is the latter which is more stpedient with regard to its simple operation. This embodiment guarantees very economical regeneration also from the point of view of energy consumption. A further aspect of this invention consists in, as an article of manufacture, the product prepared according to the present method. Further details of the invention sill be described by taking reference to the accompanying drawings which show, by way of example, embodiments of the apparatus according to the inventions and in which: Fig. 1 is a schematic illustration of a first embodiment of a drying apparatus according to the invention; Fig. 2 is a sectional view of a second embodiment of the drying apparatus, taken along the line B-B of Pig. 4; Fig. 3 is another sectional view of the second embodiment, taken among the line A-A of Fig. 4; Fig. 4 is a top view of the second embodiment of the drying apparatus shown in Figs. 2 and 3; Fig. 5 is a sectional rerspective view of a third enibodiment of the drying apparatus; Fig. 6 is a sectional top view of the third embodiment,. taken along @ the line C-C of Fig. 5; Fig. 7 is a circuit diagram of the desiccant liquid regenerator of the second embodiment as shown in Figs. 2 to 4; Figs. 8 and 9 are circuit diagrams of two other desiccant liquid regenerators applicable in the drying apparatus according to the invention; Fig. 10 is a circuit diagram of a multi-stage flash evaporator applicable as a desiccant liquid regenerator in the drying apparatus according to the invention. Same reference characters refer to same or similar elements throughout the drawings. In Figure 1 aEcasing 42 of a drying apparatus is shown schemati;cally. In the apparatus a, gas stream e.g. an air stream which dries product 50 e.g. bulk goods as shown in the figure, circulates in a closed circle in the direction of arrow 64. Circulation is forced by a fan or ventilator 66 which is driven by an electric motor 46 placed above a false roof 54 shown schematically, without its holding means in the figure. The false roof 54 has openings 47 in it which the air stream can get through. The product 50 is situated in a drying compartment 40 under the false roof 54. After flowing through the product 50the now wet air stream gets into a contacting device 43 which causes the air stream to contact with liquid films 41 of a desiccant liquid. The desiccant liquid is forced by a pump 141 into a regenerator 150. The active and hot desiccant liquid comes into the contacting device 43 from a pipeline 44 above, it gets into a pot-shape receptacle 55, from there over a pile lock 56 to a liquid distributing surface 57 facing downwards. From the liquid distributing surface 57 it gets onto downward directed liquid film conducting elements 58, e.g. fibres, said elements conduct it to a liquid outlet channel 62, from there it departs through a pipeline 45. The desiccant liquid diluted and cooled by the contact with the air stream gets into the regenerator 150 through the pipeline 45. The regenerator 150 displayed in the drawing as an example contains a multi-stage flash evaporator 151, the liquid circulating pump 141, a pump 142 for removing the distillate of the multi-stage flash evaporator 151 through a pipe end 149, and a heat-exchanger 143 which is fed with cooling water through pipe ends 144. Cooling in the heat-exchanger 143 is essential for the appropriate operation of tlie multi-stage flash evaporator 151. The active liquid leaving regenerator 150 warms up while going through condenser 145, then gets back to the contacting device 43. The condenser 145 gets the heating steam through a pipe end 146, and the condensate is carried away by a pump 147 through a pipe end 148. Elements of the regenerator 150 and the heating after the regeneration are well-known in themselves, so their detailed description is unnecessary. The embodiment according to Fig. 1 is particularly advantageous when drying products with hi:h heat tolerance e.g. bricks, as in this arrangement the temperature of the desiccant liquid ich has returned from the contacting device 43 ad has been "cooled" there is still enough for eliminating the moisture dried; the flashing process. The application of the multi-stage flash evaporator 151 shown in Fig. 1 is particularly advantageous in tho apparatus accordion. to the invention because it is froi the points of view of control, operation and reliability more favourable thec other multi-effect evaporators of the same energetic efficiency. Here the evaporation dot not take place along heat transfer surfaces, so it is less sensitive to encrustation and corrosion, and its the construction does not become complictod ever if @n@ @@ergetie effici@@cy 4 11(?d. naturally, an evaporator of different arrangement or construction per so known can equally be applied for the regeneration. Similarly, to use the contacting device 43 as shown ill Pig. I in the apparatus according to the invention in very favourable. This construction is not sensitive to the pollution getting into the liquid from the air stream, and ensures thatthe contact between the liquid and the air stream has a good heat- and mass-transfer coefficient. In.the apparatus according to the invention the drying compartment can be constructed and the product 50 to be dried can be placed in many ways (suspended, fluid -bedded, geyser, chamber, tunnel or anything else). The product can be moved during the drying process and the drying gas can equally meat the products in counter-, cross- or direct-current. Fig. 2, 3 and 4 show an embodiment of the drying apparatus according to the invention which operates with a substantially horizontally moving liquid layer 1 and with a horizontally moving product 2 above the passes liquid layer. The product 2 e.g. soybean,/through a throat 3 gets onto a transporting device, in the drawing a belt conveyor. The belt 4 has air transmitting openings 5 in it which let the air through but prevent the product 2 from falling off. he belt 4 is entrained around two pulleys 6 which are constructed to be capable of stretching and driving the belt, for this purpose e.g. they can be indented. or rubberised. One of the sprockets 6 is driven by an electric motor 8 through a driving gear 7. The loaded belt 4 of the belt conveyor transports the product 2 from the throat 3 through the drying compartment 25 which iz situated in the casing 9 of the drying apparatus, then through gate 10 transports it to a collector 11 from where the dried product is transported to the place of storing or utilization by a belt- conveyor or a pulley not shown in the figure. The empty run of the belt conveyor passes under the casing 9. In the bottom part of the casing 9, under the loaded run of the belt conveyor there is a lower air collecting space 12, and above this but under the loaded run of the belt conveyor there is a liquid vessel 13. In the liquid vessel 13 a desiccant liquid flows in the dirction of arrow 14, opposite to the product 2 which moves in the direction of arrow 15. Above the loaded run of the belt conveyor, in the tipper part of the casing 9 there is an upper air collecting space 16. Four blowers 17A, 17B, 17C and 17D driven by electric motors 23A, 23B, 23C and 23D, respectively, suck the air from the upper air collecting space 16 through respective suction ports 22A, 22B, 22C and 22D, and force it through pressure tubes 18A, 18B, 18C and 18D and through openings 19A, 19B, 19C and 19D respectively. to the lower air collecting space 12@/ From here the air @@bbl@s through bubbling c@ps 20 situ@ted in the wall of the liquid vessel 13 - one of the caps 20 is shown in a magnified form in Fig. 2 - into the desiccant liquid layer I in the direction of arrow 21, then, leaving the liquid layer 1 through the Openings 5 of the belt gets into the layer formed by the product 2 to be dried, and after going through it the air gets back to the upper air collecting space 16, thus the air circuit is closed. The liquid vessel 13 which is provided with bubbling caps 20, in this embodiment functions as a contacting device 43 which brings about contact between the air. stream and the desiccant liquid. The four blowers 17E, 17B, 17C and 171) bring about for closedly circulating partial air streams. The first partial air stream goes through suotion port 23 and meets the arriving wet product 2. The second one goes through suction port 2QC, the third through suction port 22B and the fourth through suction port 22A, and this lastone extracts from product 2 the last part of moisture to be extracted. The desiccant liquid gets into the liquid vessel 13 through pipe coupling 26 and departs through pipe coupling 27. The arriving hot and active liquid is bubbled through by the air of the last partial air streams and the departing, cooled and diluted liquid ia bubbled through by the first partial air stream. Using several partial air streams brought about by several blowers 17A, 17B, 17C and 17D is not only advantageous with respect to flow conditions bat also @cau@ @@ e@@@@@@ counter-current drying with the product 2 and the desiccant liquid 1 slowing opposite to one e another It is obvious that if there were only one single air stream circulated by one blower, there would be no counter-current drying in spite of the product 2 and the desiccant liquid 1 moving in opposite directions. The counter-curre it effect would have an optimum efficiency if there were an endless number of partial air streams circulating side by side. In this respect it is expedient to use as many partial air streams as possible in drying according to the invention. the It can be seen in Figs. 2 to 4 that/drying compartment 25 and the contacting device 43 are placed immediately above one another, forming two "floors" of the casing 9, in effect. Another embodiment of the same type of arrangement, different from the embodiment shown in Figs. 2 to 4, is that the liquid vessel 13 is placed above the loaded run of the belt conveyor. This is advantageous when the product 2 contains particles small enough to fall into the liquid vessel 13 through openings 5 of the b-elt 4, and so to pollute the desiccant liquid to an unfavourable degree, In such an embodiment the air stream entering through openings 19E, 19B, 19C and 19D would first go through the product 2, then through the liquid layer 1* Another advantage of this embodiment is that particles of tne product 2 fallen through openings 5 of the belt 4 can be collected at @he bottor of the casing 9 and from there can be transported away as dried product from time to time or continuously. It is also advantageous that liquid drops which might have been carried away from the liquid layer 1 by the air stream1 do not get to product 2 but having gone through the blowers 17A, 17B, 17C and 17D can be collected in pots or in channels formed in the bottom of tubes 18A, 183, 18C and 18D, and from there can be fed back to the liquid circuit In the embodiment displayed in Figs. 2 to 4 the pollutantswhich passed into the liquid layer 1 e.g. from the product 2 through openings 5 can be eliminated with the help of a separating tank,well-known in itself which is inserted into the desiccant liquid circuit preferably after the pipe coupling 27 in such a way, for example, that the liquid pouring into the separating tank can only depart through openings placed at half-way to the full he of the liquid level In the tank. Naturally, the tank must be cleaned appropriately9 tha fluid faust be skimmed@ deposits must be remove, The diluted desiccant liquid, in this embodiment@ the a desiccant solution, gets into the regenerator, -ir/cass- of the embodiment shown in Figs. 3 and 4,into a soluti@n- -condenser, which consists of a liquid circulating pump 28, a vapour condenser 29 which is cooled by the arriving diluted solution, a pump 30 for removing the distillato, a steam-heated evaporator 31 and a pump 36. The pump 28 p@mps the diluted solution through condenser 29 as a medium from there the solution gets into the avaporator 31 through pipeline 32. The evaporator 31 is heated by steam through pipe-joint 33 and the condensate of the heaiig steam departs through pipe-joint 34. The steam evaporated from the solution gets to the condenser 29 from the evaporator 31 through a pipeline 35, there it gets condensed and the distillate is removed by the pump 30. The system of the pump 30 is such that together with the distillate it is capable of removing the non-condensabla gases, too. From the evaporator 31 the condensed, a@tive solution is pumped by a pump 36 through a pipeline 24 to the pipe-joint 26 through which it gets back to the liquid vessel 13. This desiccant solution regenerator is way of a also shown by/circuit diagram on Fig. 7, for the sake of better understanding. In the interest of lucidity Figs. 2 to 4 show the simplest possible evaporator, which uses only the arriving solution to be regenerated as cooling medium for condensing the steam evaporated from the solution urine the regeneration. However, according to the invention, it is more practical to use instead a multi-effect evaporator, whose energetic efficiency is higher, for example as shown in Figs. 8 or 9 or a multi-stage flash evaporator, for example as shown in Figs. 1 or 10. Naturally in place of the belt conveyor some other @ransporting device ce equally be used, and the product can be taken through the drying compartment 25 not only horizontally but also obliquely. The cross-section of the liquid vessel 13 is much rigger than that of pipe-joints 26 and 27, for this reason it is practical for ensuring uniform flow conditions to let the desiccant solution stream in and out of the liquid vessel 13 not only through respective a/ single incoming and outgoing pipe coupling but through many couplings along the width of the vessel 13. Figs. 5 and 6 show another embodiment which works a with/horizontally moving product 50 and a contacting device 43 placed beside the product 50, bringing about a vertical liquid film 41 of a desiccant liquid. The product 50, sawn wood in the drawing, is p@t in carriages 51 with wheels supported in bearings on axle 52, and moves very slowly forward on floor 49 in the direction of arrow 53. Above the top of the product 50 the drying compartment 40 is closed by a false roof 54@ The whole to drying apparatus is closed from above by a shell-roof 65 which the false roof 54 is connected by suspending columns 65A. The shell-roof 65 is closed @n two sides by walls 77 and 38 respectively; the wall liave gates 39 in them for the product 50. The air stream circulates in the direction of arrows 6A under the effect of blowers 66 and 66' driven by electric motors46 srid 469 respectively. built into a separation wall 69, From the blowers 66 and 66' the air stream proc@cds between the shell-roof 65 and the false roof 54, them @hrough an opening 47 of the false roof 54 it goes ove. @@to the drying compartment 40 between the floor the false roof 54, from there it gets to liquid films 41 of the contacting device 43, then through another opening 47A between'the shell-roof 65 arid the false roof 54 back to the . blowers 66 and 662. As in the embodiment shown there are two blowers 66 and 66s, two parallel partial air streams come about. The contacting device 43 in this embodiment, as shown in Figs. 5 and 6 consists of three liquid film modules 48L, 48B and 48C placed directly side by side. Each module has an individual liquid circulation and all modules have a common lower liquid outlet channel 62 through which they are connected to a regenerator, not shown here with pipe-joints 67 and 68, The active hot desiccant liquid coming from the regenerator enters through the pipe-joint 6?, then gets more and more diluted bg circulation in liquid film modules 48A9 48B and 48C as it passes the channel 62 in the direction of arrow 63, then through the pipe-joint 68 it gets into the regenerator. The regenerator can be like the ones shown in Fig 1 or Fig. 4 but multi-effect evaporators shown in figures 8 and 9 are also suitable, and so is multi-stage flash evaporator of Fig. 10. The liquid film modules 48A, 48B and 48C are similarly constructed for this reason we describe the liquid film module 48A, only. An upper receptacle 55A is placed under false roof Sr and is bounded by a pile lock 56A. To the pile lock 56A a downwardly directed liquid distributing surface 57A is connected. From the liquid distr@buting surface 57A there are liquid film conducting elements 58A, e.g. fibres as shown in the drawing, going down. Along the periphery of each of the elements 58Q a liquid film comes about, all the elements 58A belonging to the liquid film module 48t together make up a liquid film group whose characteristic feature is that all the elements in the group conduct desiccant liquid of the same concentration. The elements 58A reach down to the lower collecting channel 62 placed beneath. A suction pipe 59A starts from the bottom of the channel 62 thus conducts the desiccant liquid to a liquid circulating pump 60A. The pump 60k circulates the liquid through a tube GlA into the upper receptacle 55A, from there thro@gh the pile lock 56A it gets to the liquid distributing surface 57A, and then, along the elements 58A into tho lower collecting channel 62. The upper receptacle 55A is separated from the upper receptacle of the neighbouring liquid film module 48B, but the common lower channel 62 makes it possible for the liquid ccu1ating circuits belonging to tubes 61A, 61B and 61C pass liquid to one another through it Sections o w lower channel 62 which belong to Liquid film modules 48A, 483 and 48C, respectively are separated from one another by separating elements 162 pro with openings, so that the liquid stream is always flowing in the direction of arrow 63, without a mixing effect backward. Starting in the direction of arrow 63 the f,trst liquid circulating circuitbelonging to the first liquid film module 48C gets the hot and active liquid from the regenerator. This is diluted by the air stream coming from the drying compartment 40, so the liquid delivered to the second liquid circulating circuitbelonging to the liquid flow module 48B In the form of overflow of the first licud circulating circle is somewhat diluted. It is the overflow of the last - in the drawing the thIrd liquid circulating circuit which gets back as diluted and cold desiccant liquid to the regenerator, said liquid containing all the moisturo which had been extracted from the product 50 by the air stream. The two blowers 66 and 66' bring about two parallel partial air streams. The velocity of each of such the partial air streams should be of a value / that: the liquid films along the conducting elements 58A, 58B and 58C are not disturbed by the air stream, i.e. the air stream does not carry off liquid particles from the film. A velocity of 1 to 5 m/sec is suitable. The embodiment shown in Digs. 5 eua 6 - similarly to that shown in Figs. 2 to 4 - carries out counter-current drying, as the product 50 moving slowly in the direction of arrow 3 while going through the drying compartment; 40 meets air streams which hat been contacted with more and more active desiccant liquid. A prerequisite of said counter -current drying here, too,is to have at least two partial air streams. It is expedient to have one partial air stream belonging to each liquid film module 48A, 48B and 48C that is, the number of blowers should be equal to that of the liquid film modules. The concentration of the desiccant liquids circulated in tha liquid film modules 48A, 48B and 48C can be increased in a sequence different from that of the modules in space. The sequence can be arranged as seems best with appropriate joining of individual sections of the channel 62 belonging to individual modules. For instance, from the section oi ths channel 62 belonging to liquid film module 48C the desiccant liquid can get into the section belonging to liquid film module 48A instead of the one belonging to liquid filni module 48B through the separating element 162, and from there into the section belonging to liquid film module@48B. In such a way the apparatus according to the invention can be programmed with regard to the drying requirements 3 the product 50 going through the drying compartment 40. In the embodiment shown the contacting device 43 borders the drying compartment 40 on the left hand side, ,as it were, forming/a "liquid curtain". As the liquid film 4@ brought about according to the invention is essentially dropless, the contacting device 43 can also be placed on the right hand side of the drying compartment 4O, more- over it can be placed in such a way that it divides the drying compartment 40 into two parts, e.g. between the two stacks of wood shown in Fig. 5. According to tile invention time only important thing is that the closed should air stream/go through the contacting device 4@ @@@@@@ recirculation, and the contscting device 43 and the drying @@mpartment 40 are arrang@d and placed in such a way that the air stream suffers the le@st possible alteration of velocity and direction when going from one to the other. It is obvious that these conditions are fulfilled in all the embodiments mentioned. The type of the contacting device 43 shown in Fig. 5 is the same as that shown in Fig. 1, but it can also be made in a different way. Several contacting devices applicable in the apparatus according to the invention are described in U.S. Patents No. 3,857,911@ and 4,009,229, in Hungarian Patent No. 168,451 and in British patent No. 1,363,523. In the apparatus according to the inventIon it is highly advantageous to apply an aqueous solution of calcium chloride in the concentration o@ 40 to 50 % as a desiccant liquid. The pollution getting into the desiccant solution can be eliminated with a tank in he same way as described in connection to the embodiments shown in Figs 2 to 4. In Figs, 5 and 6 we do not show a regenerator as it can be the same as that in any of Figs. 1, 4, 8, 9 any 10. With the appropriate sslection of regenerator it is also possible to ensure for the active solution arriving through pipe-joint 67 to be as hot as is needed so that It can heat the air stream and through it the product50. @ith the help of liquid film modules 48A, 48B and 48C it is possible to set -a temperature program lor the product 50 going through the orying compartment 40. Figs. 7, 8, 9 and 10 show various embodiments for the regenerator. Having considered that the regenerator comes about from different connecting of devices per so known, the variou regenerators to be applied in the invention are shown in Figs. 7, 8, 9 and 10 only with circuit diagrams. For the sake of clarity we marked each operation with a separate schematic sign in the circuit diagrams but the invention can be realised also in such a way that, for instance, more than one advice is placed into one casing. Fig. 7 represents the circuit diagram of the regenerator shown in Figs. 2 to 4 and described in relation to these Figures in deatil. Fig. 8 represents a regenerator which uses the steam evaporated from the desiccant liquid for making to boil the liquid to be regenerated, and the steam coming of the departing active liquid heats the incoming diluted liquid. This regenerator is a multi-effect evaporator. The dilated liquid is pumped by a pump 70 into a condenser 71, there it serves as cooling medium for the condenser 71s then while cooling the liquid evaporating in heat exchangers 72 and 73 it gets warmed further, finally it gets lnto an eva.porat6r 75 through a pipeline 74. This evaporator 75 is heated from the outside with heat taken in. or instance, according to the embodiment shown steam is taken In through a pipe-joint 76, this gets condensed and the condensate departs through a pipeline 77. Of course, flue gas, radiant heat, solar @@ergy or something el@e can @lso be used for heating. From here through a heat exchanger 75 and a throttl@ 78 the liquid gets into an evaporator 79, where it is further boiled by the steam produced in the evaporator 75. Form here a pump 83 pumps the liquid through the heat exchanger 72 to a pipe-joint 80 which is connected to a pipe-joint conducting the active liquid in the dryer body itself, erg to the pipe-joint 67 in Fig. 6. The steam produced in the evaporator 79 through a pipeline 84 and the condensate of the steam heating the evaporator 79 through a throttle 81 get in the condenser 71 and both heat there the diluted, incoming desiccant liquid. The condensed d'istillate and the non-condensable gases are removed by @ pump 82. ig. 9 shows the circuit diagram of an embodiment of the regenerator which is also a multi-effect evaporator and uses the stearn evaporated from the diluted liquid for heating the incoming diluted liquid to be regenerated. The diluted liquid is pumped to a condenser 91 by a pump qO as cooling medium, there it warms up, then cooling the depart already condensed liquid in the heat exchanger 92 it goes on warming and gets into an evaporator 93. From here a pump 94 takes it through a heat exchanger 95, where cooling the active liquid it gets warmed, further to an evaporator 96. Here it is evaporated with heat taken in from outside, for example with steam taken in through a pipe-joint 97. The condensate of the steam departs through a pipe-joint 98. The steam which had @ome a@@@@ in the evaporator 96 boils the diluted liquid in the evaporator 93. The condense@, @@tive liquid through a pipeline 99 gets into the heat exchanger 95, then into the heat exchanger 92, and departs' through a pipe-joint 100 towards the dyer body e.g. to the pipe-joint- 67 in Fig. 6. The steam produced in the evaporator 93 gets into the condenser 91 through a pipeline 101, the condensate of the steam heating the evaporator 93 gets into the same place through a throttle 102, there it heats the diluted liquid then the disttllate produced by condensation and the non gases condensable/are carried away by a pump 103. Fig. 10 shows the circuit diagram of a further embodiment of the @egenerstor in which the heat released during condensing the steam evaporated from the liquid by flash only warms the liquid to be regenerated but does not evaporate it. This regenerator is a multi-stage flash evaporator. The diluted liquid is driven through condensers 112, 113 and 114 by a pump 111. On leaving the condenser 114 the liquid goes through a throttle 115. The pump 111 and the throttle 115 are arranged in such a way that the rressure of the liquid when going through condensers 112, 113 and 114 is bigger than the saturation pressure all the way thro@@h,so vaporization does not occur any@here. The temperature of the diluted liquid serving as cooling liquid in condensers 112, 113 and 114 is increasing. After the throttle 115 in an evaporator 116 steam is released from the liquid without heat transfer. This steam gets condensed in the condenser 113. The liquid goes on to an evaporator 117 where more steam s released from it which gets condensed in the condenser 112. The condensed active liquid that is leftis carried back to the drying body by a pump 118, e,g. in Fig. 6 to the pipe-joint 67. The distillate condensed in the condenser 113 rough a pipe line 119 gets to the condenser 112, where it flashes. The distillate and the non-condensable gases are pumped away by a pump 120. In the condenser 114 the diluted liquid to be regenerated should be heated by heat taken in from out- side, for example with steam taken in through a pipe-joint 121, the condensate ol the stean departs through a pipe -joint 122. With respect to the control of equipments of the regenerator it is expedient to alter the embodiments described above in such a way that only a part of the diluted desiccant liquid gets concentrated and the other part is mixed with the concentrated part. It is this mixture which has to be used as active desiccant liquid in the drying body. For the sake of simpler description in the embodiment above we showed two evaporators i.e. two stages only, but of course it is possible and advisable in the interest of increasing the energeti@ efficiency to apply more stages. In Fig. 10 it is shown that when the surplus heat produced by the regenerator cannot be utilized in the drying bodg or when the heat loss of the drying body is little (e.g. in summer) the desiccant liquid regenerating system should be balanced. In Fig. 10 there are two expedient solutions applicable separately but also together. As to the first solution the condenser 112 must be provided with cooling medium from the outside e.g. cooling water and coolable subsidiary surface e.g. coil pipe This latter can be placed in a se arate casing, in such a case the steam spaces must be c@nnected with pipe lines. Cooling water can for example enter the beat exchanger through a pipe-joint 123 and leave it through a pipe-joint 124. According to the second solution on the diluted liquid entering the condenser 112 is pre-cooled in a heat exchanger 127 which is cooled back a medium e.g. water entering through a pipe-joint 125 and leavir&num; through a pipe-joint 126. In the embodiments according to Figs. 7, 8 and 9 these two solutions are also applicable. In this respect an equivalent of the condenser 112 cooled additionally in Fig. 10 is she condanser 29 in Fig. 7, the condenser 71 in Fig. 8 and the condenser 91 in Fig. 9. The beat exchanger 127 shown in Fig. 10 must be inserted between the condensers 29, 71 and 91 and the pumpe 28, 70 and 90 of Figs. 7, 8 and @, respectively situated before said condensers As various changes might 6e made in the embodiments herein disclosed without departing from the scope of the invention,, it is understood that all matter herein shown or described should be deemed illustrative and not by way of limitation. Reference numbers in drawings Figs. 2, 3, 4 and 7 1 liquid layer 2 product 3 throat 4 belt 5 openings 6 wheel 7 driving, gear 8 electric motor 9 casing 10 gate 11 collector' 32 lower air collecting space 13 vessel 14 arrow 15 arrow 16 upper air collecting space 17A,B,C,D ventilator 18B tube 19A,B,C,D opening 20 bubbling caps 21 arrow 22A,B,C,D suction port 23A,B,C,D electric motor 24 pipeline 25 drying compartment 26 pipe-joint 27 pipe-joint 28 pump 29 condenser 30 pump 31 evaporator 32 pipeline 33 pipe-joint 34 pipe-joint 35 pipeline 36 pump Figs. 1, 5 and 6 37 wall 38 wall 39 gates 40 drying compartment 41 liquid film 42 casing 43 contacting device 44 pipeline 45 pipeline 46, 465 electric motor 47, 47A opening 48A,B,C liquid film module 49 basement or floor 141 pump 142 pump 143 heat-exchanger 144 pipe ends 145 condenser L46 pipe end 147 pump 148 pipe end 149 pipe end 150 regenerator 151 multi-stage flash evaporator 50 product 51 carriage 52 axle 53 arrow 54 false roof 55, 55A receptacle 56, 56A pile lock 57, 57A liquid distributing surface 58, 58A,B,C, liquid film conducting elements 59A suction pipe 60A pump 61A,B,C tube 62 channel 69 arrow 64 arrows 65 shell-roof 65A suspending column 66, 66' ventilator 67 pipe-joint 68 pipe-joint 69 separation wall 162 separating element Fig. 8 70 pump 71 condenser 72 heat exchanger 73 heat exchanger 74 pipeline 75 evaporator 76 pipe-joint 77 pipsline 78 throttle 79 evaporator 80 pipe-joint 81 throttle 82 pump 83 pump 84 pipeline Fig. 9 90 pump 91 condenser 92 @est exchanger 93 evaporator 94 pump 95 heat exchanger 96 evaporator 97 pipe-joint 98 pipe-joint 99 pipeline 100 pipe-joint 101 pipeline 102 throttle 103 pump Fig. 10 111 pump 112 condenser 113 condenser 114 condenser 115 throttle 116 evaporator 117 evaporator 118 pump 119 pipeline 120 pump 121 pipe-joint 122 pipe-joint 123 pipe-joint 124 pipe-joint 125 pipe-joint 126 pipe-joint 127 heat exchanger

Claims: CLAIMS 1. A method of drying products comprising the steps of introd@@ing the product to be dried into a drying compartment; continuously past circulatdng a drying gas stream so as to pause it to pass/ the product to be dried; contacting the drying gas stream with a desiccant liquid to remove moisture from the gas; and regenerating the desiccant liquid by circulating at least a part of it through regenerating means which remove moisture therefrom characterized by producing at least one layer of the desiccant liquid in the vIcinity of the product being in the drying compartment , and contcting the drying gas stream with said at least one desiccant liquid layer. 2, The method according to claim k characterized in that said at least one desiccant liquid after is a substantially horizontal liquid layer, and said drying gas stream is bubbled through said substantially horizontal liquid layer. 3. The method according to claim 1, characterized in that said at least one desiccant liquid layer is produced by causing the desiccant liquid to flow on liquid film conducting elements, and 'said contacting is pergorme by casing said drying gas stream to pass between said liquid fI'm conducting elements, 4. B method of drying products <RTI ID=40.42> comprising the steps of introducing the product to be dried into a drying compartment; comt@@uously past circulating a drying gas stream so as to cause it to pass/the product to be dried; contacting the drying gas stream with a desiccant liquid to remove moisture from the gas; and regenerating the desiccant liquid by circulating at least a part of it through regenerating means which removes moisture therefrom, characterized by bringing about a heat exchange between the desiccant liquid and the product to be dried so that the heat is transmitted by the drying gas stream between the desiccant liquid and the product to be dried. 5. The method according to claim 4, characterized in that said heat exchange is performed by heating the desiccant liquid in the course of said regeneron so that the drying gas will be heated to a predete@@ined temperature by contacting the desiccant liquid during said gas circulation. 6. The method according to claim 5, characterized in that said predetermined temperature of the drying ga@ is at least 40 C. 7. The method according to any o@ claime 1 to 6, @haracterized ii shat said desiccant liquid is a desiccant solution; said regenerating is performed by evaporating the desiccant solution; and the steam evaporated from the desiccant solution is at least partly condensed by the desiccant solution to be regenerated. 8. The method according to claim 7, characte@@@@é by that said evaporation is performed by multi-effect evaporation; and the steam evaporated during the first @oiling @f the desiccant solution is at least partly @ondensed by the incoming desiccant solution to be regenerated. 9. The method according to claim 7, characterized in that said evaporation is performed by a multi-effect evaporation; and the steam evaporated during the last boiling of the desiccant solution is at least partly condensed by the incoming desiccant solution to be regenerated. 10. The method recording to claim 7, characterized in that said evaporation is performed by multi-stage flashing. 11. The method according to any of claims 7 to 10, characterized by furthe@ comprising the step of cooling the desiccant solution after said contacting and before said regenerating in dependence on the cooling of the desiccant solution during said contact so that the incoming desiccant pollution to be regenerated is of a predetermined temperature. 12. The method according to any of claims 4 to 6, characterized by further comprising the step of producing at least one layer o@ the desiccant liquid in the vicinity of the product being in tne drying compartment, and contacting said gas stream with said at least one desiccant liquid layer. 13. The method according to any of claims 1 to 12, characterized in b-hi;,t said continuous circulation of the drying gas stream is performed by conducting the drying gas stream In a path section between the product to be dri@ and the desiccant liquid so that in said path section the ratio of the maximum and minimum velocity of the drying gas stream is smaller than five to one and the change of direction of flow of the drying gas stream is less than 30 degrees. 14. The method according to claim 13, characterized in that said drying ,as stream is conducted between the product to be dried and the desiccant l@quid substantially without any alteration of velocity and direction. 15. The method according to any of claims 1 to 14, characterized in that said desiccant solution is an aqueous solution of calcium chloride, and the drying gas is air. lo. The method according to any of clamis l to 15, characterized by that said drying gas stream consists of at least two parallel partial gas streams; the product to be dried is moved across said partial gas streams; and each of said partial gas streams is contacted with a desiccant liquid of specific concentration and temperatur 17. The method according to claim 16, characterized in that each of said partial gas streams is contacted with a more concentrated desiccant liquid than the desiccant liquid contacting the previous partial gas stream with respect to the direction of movement of the product to be dried. 18. The m@ thod according to claim 16 or 17 cheracterized by further comprising the steps of producing at least two separated groups of desiccant liquid films of different concentration; placing said grups of desiccant liquid films side by side in the- We of said partial gas streams so that each of said partial gas streams is contacted with its own at least one group of desiccant liquid films. 19. The method according to claim 18, characterized in that each of said groups of desiccant liquid films is provided with its own liquid circulation or flow circuit; the liquid circulation or circuit of the last group with respect to the direction of movement of the product to be dried is fed with the regenerated desiccant liquid coming from said regenerating means; the circulation or circuit of each preceding group is fed with the overflow of the circulation'or circuit of the subsequent group, and the overflow of the circulation or circuit of the first group is conducted into said regenerating means. 20. An apparatus for drying products comprising at least one drying compact rut (25, 40) for the product (50) to be dried; at least one contacting device (43) for contacting a drying gas stream (64) with 2 desiccant liquid (413 to remove moisture from the gas; gas conducting means (58) for conducting the drying gas stream In a substantially closed path through said drying compartment (25, 40) and the or each said contacting device i43); gas circulating means (66;17A;17B;17C;17D) to cause the drying gas stream to circulate along said closed path; regenerating means (150) for removing moisture from the desiccant liquid; and liquid circulating means (36,141) for circulating at least a part of the desiccant liquid through said regenerating means (150) and the or each said contacting device (4-3) characterized in that the or each said contacting device '43) includes means (13,58) for producing at least one layer (1,41) of the desiccant liquid to be- contacted with the drying gas stream; said at least one desiccant liquid layer (1, 41) being located in the vicinity of the product (2, 50) being said drying compartment (25,40). 21. The apparatus according to claim 20, characterised in that the or each said contacting device comprises a vessel (13) for producing a substantially horizontal des iccant liquid layer (1), said vessel (13) having on its wall bubbling caps (20) for bubbling the drying gas stream through said liquid layer (1), said vessel (13) being connected to said liquid circulating means (36) so as to cause the desiccant liquid to flow along said vessel, and said drying compartment (25) being located above or below said vessel (13). 22. The apparatus according to claim 21, characterised in that said drying compartment (25) comprises a device (4) for transporting the product (2) to be dried through said drying compartment, said transporting device (4) having openings (5) for letting through .the drying gas stream, but not letting the product (2) to be dried drop. 23. The apparatus according to claim 22, characterised in that said transporting device is an endless belt conveyor (4) and said gas circulating means are ventilators or blowers ( 17A, 17B, 17C, 17D) placed side by side along said belt conveyor (4). 24. The apparatus according to claim 20, characterised in that the or each said contacting device (43) comprises liquid film conducting elements (58) places so that the drying gas stream is passing between said liquid film conducting elements (58). 25. The apparatus according to claim 24, characterised in that the or each said contacting device (43) further comprises a receptacle (55) for receiving and holding the incoming desiccant liquid, at least one pile lock (56) to guide in film form the liquid out of said receptacle (55), liquid distributing means having at least one distributing surface (57) connected to said at least one pile lock (56) and facing downwards, and liquid outlet means (62), wherein said film conducting elements (56) are connected between said liquid distributing surface (57) and said liquid outlet means (62) so that they conduct liquid films (41) from said surface (57) into said outlet means (62). 26. The apparatus according to claim 24 or 25, characterised in that said liquid film conducting elements (58) are arranged in at least one substantially vertical plane which is substantially perpendicular to the direction of the drying gas stream. 27. The apparatus according to claim 26, characterised by further comprising a basement or floor (49), a shellroof (65), and a false roof (54) provided with openings (47,47A) for letting through the drying gas stream and located between said basement or floor (49) and said shellroof (65), wherein said drying compartment (40) is located between said basement or floor (49) and said false roof (54), said gas circulating means are ventilators or blowers (66,66') placed between said false roof (54) and said shell-roof (65), the or each said contacting device (43) is placed at said drying compartment (40) so that said at least one vertical plane formed by said liquid film conducting elements (58A,58B,58C) is substantially perpendicular to the drying gas stream and extends between said basement.or floor (49) and said false roof (54). 28. The apparatus according to any of claims 24 to 27, characterised in that the or each said contacting device (43) consists of at least two liquid film modules (48A,48B,48C) placed side by side, each liquid film module (e.g. 48A) has its own liquid film conducting elements (e.g.58A) and own liquid circulating device (e.g.6OA,61A) providing a liquid flow circuit to form the liquid films on said own conducting elements, and said liquid film modules (48A,48B,48C) are provided with a common liquid channel (62) interconnecting said liquid circulating devices, said common liquid channel (62) being connected to said liouid circulating means (e.g.36). 29. The apparatus according to any of claims 20 to 28, characterised in that the ratio of any two flow cross-sections of said gas conducting means (37,38,49, 54) between said drying compartment (40) and a said contacting device (43) is between 0.2 and 5; and the or each said contacting device (43) is located at said drying comnartment (40) so that the drying gas stream is flowing between the product (50) to be dried and said contacting device (43) with a directional change of less than 30 degrees. 30. The apparatus according to claim 29, characterised in that said flow cross-section ratio is between 0.5 and 2, and said directional change is substantially zero degree. 31. The apparatus according to any of claims 29 or 30, characterised in that the distance between said drying compartment (40) and the or each said contacting device (43) is less than the hydraulic diameter of said gas conducting means (37,38,49,54) between them. 32. The apparatus according to any of claims 20 to 31, characterised by that said regenerating means (iso) comprises a multi-effect evaporator (e.g.70 to 84). 33. The apparatus according to any of claims 20 to 31, characterised by that said regenerating means (150) comprises a multi-stage flash evaporator (151). 34. As an article of manufacture, a product prepared according to the method of any or claims 1 to 19, or by the apparatus of claims 20 to 33.

Inventors: HORVATH, ANDRAS, SIGMOND, EMOD, SZUCS, LASZLO, WAERMER, GYORGY, Horváth, András, Sigmond, Emöd, Szücs, Lászlo, Waermer, György
Applicants: ENERGIAGAZDALKODASI INTEZET
Application year: 1979
Main classification: F26B21
IPC codes: F26B5, F26B21, F24F3, F26B3, B01D1