EP0226605A1 - Process and device for multiple-phase processing of aqueous liquids - Google Patents

Abstract

A method and apparatus for the multi-phase treatment of an aqueous liquid, in which a pre-cooled aqueous liquid (38 ') (151) is processed into a mill under three-point conditions, for injection into a condensation chamber ( 1) subjected to a partial vacuum; the droplets (7) are supercooled by partial evaporation and are collected in the form of a mill in the manifold (8) of the chamber. The strawberry is processed according to the intended application, such as concentrating fruit juice or chemicals, treating wastewater, or converting the strawberry to blocks of ice or a concentrated, pumpable strawberry mill. (163), containing about 70% ice for cooling, especially in underground mines. The thermal efficiency is also improved by the fact that the low pressure steam (26, 103), after extraction, from the condensation chamber (1), is transformed into high pressure steam (119 ') in a conversion phase of the absorption pressure (104-108) followed by desorption (112) by heating at high pressure, and mechanical compression (115) as well as condensation (113, 111 ').

Description

 METHOD AND DEVICE FOR THE MULTI-PHASE TREATMENT OF AQUEOUS FLUIDS

The present invention relates to a method and a device for the multi-phase treatment of an aqueous liquid and in particular to a method for converting an aqueous liquid into an egg pulp and subsequent treatment of the ice slurry. In a particular respect, the invention relates to a method and a device for the concentration and / or crystallization of aqueous solutions, in particular of those that occur in food technology and chemistry. Examples of this are the concentration of fruit juices, organic and inorganic acids as well as the crisis from waste water from various industrial branches.

In a further respect, the invention relates to the production of an egg pulp and various uses thereof, in particular the conversion into an ice pulp pumpable consistency and its use for artificial purposes, or the conversion of the ice pulp into solid ice blocks or pellets. In this context, too, the invention entails a concentration build-up in the liquid phase of the ice pulp, but not the solids present in the original aqueous liquid.

In a further respect, the invention is efficient on a method and a device for extracting water vapor of low density and temperature with a pressure transformer and subsequent compression with a mechanical compressor to achieve a comparatively high overall efficiency. Known sinα evaporators with which the build-up concentration of the type mentioned is usually carried out. Such systems have the disadvantage that they work at high temperatures (eg 70 to 100 ° C) and thus favor the formation of dirt and incrustations on system parts. Soiling occurs primarily with temperature-sensitive products, e.g. through biological reactions.

So you are often forced to clean the systems after a short period of operation (e.g. every 24 hours). High temperatures also have the disadvantage that more volatile constituents, primarily the flavorings in food products, pass into the vapor phase. These can only be recovered with complex separation equipment, such as rectification columns or the like. Since corrosion rates also increase exponentially with temperature, high temperatures require the use of high-quality materials (stainless steel, nickel, titanium, etc.). Finally, the increase in the boiling point requirement with increasing concentration should be pointed out, which is noticeable by a higher energy requirement during evaporation.

In the present context, a method and a device for the desalination, in particular of sea water, are known, in the literature known as vacuum evaporation vaporization processes, of which a large-scale version is known as a "hydroconverter" (KS Spiegier, Principles of Desalination, page 310 ff., (1966) Academic Press, New York and London). Apparently, this technology was not known for any purposes other than seawater desalination, where the product consists of pure water, melted ice and condensed steam condensates, but not for other applications where ice or ice cream was used as a product, or for Application in crystallization and Concentration processes, such as those used in the fruit juice and chemical industries. Although the possibility of spraying pre-cooled sea water into a vacuum freezer chamber is mentioned, the industrially preferred method in the hydroconverter uses a kind of falling film evaporation, whereby the sea water runs down as a thin film on the walls of the freezer chamber. In both cases, the sump in which the ice pulp collects in the freezer chamber is flat and the vacuum space above the ice pulp, where the evaporation takes place and from which the steam is extracted, is also relatively low. This results in the disadvantage that the brine tends to be carried along with the vapors and sucked out of the vacuum chamber. A pre-separation of the ice pulp in ice and liquid phase in the flat sump part of the device does not take place, and the ice pulp is withdrawn as a whole from the sump.

The use of an ice pulp for ice cream production or for cooling purposes is also not to be found in this prior art, and is also not intended, especially since this prior art does not contain any teaching on how to achieve the efficiency, in particular the energy efficiency, for such an application on an industrial scale to make interesting.

Systems and methods of the type provided according to the invention for producing an ice slurry, by evaporating an aqueous liquid under reduced pressure and re-compressing the extracted vapors, require the use of multi-stage mechanical compressors. It is known that the size, and thus the weight and the mechanical losses, of a mechanical compressor are dependent on the suction volume flow. It is also known that the specific volume of a vapor in the saturated state increases sharply with decreasing pressure. Since the polytropic compression work to be used t only from the mass flow depends on the specified pressure ratio and medium, the energy required for compression in the reversible case is independent of the volume flow. However, the suction volume flow is of corresponding importance for the size of a compressor and thus for the mechanical losses that affect the overall efficiency.

When compressing steam with saturation temperatures between 60 and 100 ºC, compressors achieve overall efficiencies of 75 to 80%. However, if the saturation temperatures are between 0 and 5ºC, only efficiencies of 50% are achieved. This enormous difference results from the fact that the diameter of the impeller for compressing the same mass flow at 0ºC is 5.7 times as large as at 61ºC, and the mechanical losses are considerably greater, not to mention the high cost of such a large device.

A task of the invention is to achieve a gentle concentration or effective crystallization at low temperatures and low energy consumption by creating a method and a device.

In another respect, it is also an object of the invention to provide a method and a device in order to reduce the energy requirement of the thinning in certain situations and thus to increase the overall efficiency.

In one respect, a method is provided according to the invention for converting an aqueous liquid into an egg pulp with subsequent subsequent treatment of the ice slurry, characterized in that the liquid is injected into an evaporator space which is expanded to a pressure. which is the saturation pressure at the corresponding vaporization temperature of the liquid in the Evaporation space at -5 to 10ºC corresponds, so that the liquid partially evaporates due to a phase imbalance caused by a short residence time in the evaporation space and cools down to a low temperature and is then collected with a sufficiently long residence time, so that this occurs due to an Equilibrium forms an ice slurry, the ice slurry is drawn off and subjected to a separation of the liquid phase from the ice slurry, followed by one or more of the following process steps:

a) obtaining a concentrate of the aqueous liquid,

b) obtaining or removing substances dissolved in the aqueous liquid in precipitated or other phase-separated form,

c) Obtaining the ice as concentrated ice pulp or as solid blocks or pellets.

In particular, an aqueous solution, for example a solution to be concentrated, is relaxed after pre-cooling through a nozzle system to a low pressure which corresponds to the saturation pressure of the corresponding evaporation temperature of -5 to 10 ° C, such that the solution is adjusted by setting an imbalance partially evaporated, cooling to a low temperature. The imbalance is achieved in that the nozzle system creates fine drops that have a very short residence time in the steam room. The drops are then collected and then, with a sufficiently long dwell time in the swamp, form an ice pulp which is passed into a separator and freed of ice. The product is drawn off from the separator, while after washing off the attached product, the ice is melted and used to pre-cool the fresh solution. The steam created by imbalance is suctioned off with the aid of a compressor and fed to a condenser in which the washed-out egg is melted and then used to pre-cool the incoming solution.

The process just described has the following advantages: The low temperature means that more volatile constituents (e.g. flavorings) are retained in the product. The rate of corrosion is very low, and it. cheap materials can be used. Biological and other chemical reactions are also strongly inhibited. This allows long periods of operation between cleaning periods. The low energy consumption of the system is also of particular advantage.

According to a preferred development of the invention, the spraying into the evaporator chamber takes place reasonably close to the surface of the ice pulp collected in the room and at a short distance from the top of the evaporator chamber, where the vapors, after extensive separation of the droplets, and preferably after a passage through a defogger. Compared to falling film evaporation, the selection of a liquid injection according to the invention offers the advantage of particularly effective presentation of the liquid surface in order to achieve rapid evaporation and under-cooling of the droplets. This also avoids the tendency towards ice accumulation in the name of the water inlet, as reported in the literature regarding the hydroconverter's falling film method, at the top of the vessel. The supercooled droplets settle relatively evenly over the entire surface of the ice pulp that collects in the lower part of the evaporator chamber, and the relatively large height of the room above the injection points and the relatively low flow velocity of the vapors in the room ensure this , that a comparatively complete separation of the droplets from the vapors takes place before the vapors are suctioned off, preferably after a further defogging process by means of conventional droplet separating devices.

In a further aspect, preferably combined with the above-described inventive concept, a method is provided for converting low-pressure steam into steam of higher pressure by means of a pressure transformer stage in which the low-pressure steam is mixed in an absorber with absorbent and is absorbed by it, wherein the heat of absorption of coolant, in particular is dissipated by cooling water, and in which the resulting absorption medium, enriched with the liquid supplied by the steam, in particular water, after a pressure reduction by a pump is first heated by heat exchange, and then passed into an expander , in which a steam at higher pressure is generated by the supply of heat.

A steam absorption method can also be found in connection with sea water desalination in the above-mentioned literature (KS Spiegier), but without the vapors extracted from the steam expeller part of the absorber system being under pressure and being fed to a further mechanical compression, be it for Purpose of condensing the vapors, and optimizing energy efficiency or for other purposes. On the contrary, the vapors are suctioned off under vacuum.

The invention also relates to devices and systems for carrying out and using this method.

In particular, the invention provides that the steam generated in the expeller compresses higher pressure with the aid of a compressor and the boiler room of the expeller as a heating medium is fed in, which condenses after the condensation heat has been given off and then leaves the expeller. According to preferred embodiments, the solution depleted in the expeller with regard to the absorbed steam, in particular water, is used in a heat exchanger for heating the steam-enriched solution arriving from the absorber and then fed to the absorber via a throttle valve.

The inert gases released in the absorber are preferably collected and drawn off by a vacuum pump.

In summary, the invention teaches in the above-mentioned respect that between the place where the low-pressure steam is extracted and the mechanical compressor, a pressure transformer is switched, which effects a pre-compression of the steam to be extracted, whereby the specific volume is considerably reduced, and the mechanical compressor Compression of the same mass flow, built correspondingly smaller, and so can be operated with a higher overall efficiency. The

Precompression is achieved by first mixing the low pressure steam in an absorber with an absorbent, from which the steam is absorbed. At the same time, the heat of absorption released is dissipated by cooling water. The solution enriched with steam (water-rich solution) is then sucked out of the absorber with a solvent pump and pumped to the evaporation pressure.

The rich solution is then heated in a heat exchanger and then flows into the steam expeller. The low-pressure steam previously absorbed in the absorber evaporates at the selected higher pressure level. The high pressure steam generated in this way is compressed with a mechanical compressor, its pressure and temperature increase. The steam then penetrates into the expeller's boiler room, condenses there and thereby supplies the heat required for evaporation. The heat contained in the condensate can continue to be used in the process. The solution (poor solution) which is depleted of steam (water) in the expeller is fed into the previously heated heat exchanger, where it cools down and supplies the energy required to heat the rich solution. The poor solution then flows through a throttle valve, undergoes relaxation to the lower absorber pressure, and enters the absorber, which closes the circuit.

LiBr, NaOH, Ca (OH) ₂ , MgCl ₂ , CH ₂ NH ₂ or CaCl ₂ can be used as absorbents.

The principles of the invention that apply in this regard can also be advantageously applied to the condensation of vapors from the vacuum and from the vapor. out

Use the freeze-drying process.

In particular, the invention also relates to a method and a device for concentrating or crystallizing aqueous solutions, in particular fruit juices, organic and inorganic acids and salts, as waste water, characterized in that the solution to be concentrated or crystallized is via a nozzle system Evaporation is supplied at which the solution is depressurized to a pressure corresponding to the evaporation temperature of -5 to + 10 ° C, which corresponds to the saturation pressure, so that the solution partially evaporates due to an imbalance caused by a short residence time, and thereby evaporates cools to a low temperature, and is then collected after a sufficiently long dwell time, so that it forms an ice pulp due to an established equilibrium with the other Characterize that the vapors formed under low pressure during evaporation are converted into high pressure vapor by means of a pressure transformer stage of the type described above.

It has proven to be particularly advantageous if the ice pulp is already experiencing a partial visual force separation of the liquid from the ice in the evaporator space and the ice pulp thus concentrated is drawn off in the area of the top of the ice pulp in the evaporation space, where the ice-to-liquid ratio is highest. This separation is promoted by the considerable depth of the swamp.

The ice slurry is preferably skimmed mechanically from the top region in an enriched form.

This has the advantage that the ice pulp extracted from the evaporation space requires less additional concentration than would otherwise have been the case if the ice pulp were removed in a conventional manner from the bottom of a flaky swamp. Another advantage is that the ice floating on the top of the ice pulp in the evaporator chamber is washed by the settling liquid droplets in which the content of dissolved. Substances is less than in the liquid nose of the ice pulp.

Another important preferred characteristic is that the evaporation into the evaporator chamber is directed upwards from below the surface of the collecting ice slurry.

This characteristic is intended to counteract the tendency of the glands to freeze.

The invention also offers devices for Implementation of various aspects of the invention are suitable. And in one respect such a device is characterized by an evaporator required for the production of ice slurry with a container which has a nozzle system in about half, contains a collecting container in the lower part, and is provided with demister in the upper part, and in has its lower part of an ice sludge extraction and conveyor, in particular a screw pump, and facilities for further treatment of the ice slurry are switched.

A special version provides a separating device, consisting of a container with an upper and lower tube sheet, into which a bundle of tubes is embedded, which consist of a pure material, such as membrane or mesh, and the lower tube sheet an inlet chamber with an inlet for Recording of the ice pulp and its forwarding is assigned to the Ronroündel, while there is a receiving chamber for the ice-enriched treated ice pulp above the upper tube sheet.

The freeze evaporator preferably has a device for removing the ice slurry in a region of the evaporator in the vicinity of the surface of the ice slurry in the evaporator. The removal device preferably has a mechanical skimming or wiping device. The hone of the removal device can preferably be adapted to the level of the ice slurry in the evaporator device. For this purpose, the removal device can be set up to drive on the porridge surface. It is a preferred feature that the nozzle device has upwardly directed nozzles below the normal ice level.

In a further respect, and preferably combined with the characteristics described above, it is provided that between the vapor extraction area and a mechanical To dilute the vapors removed from the vaporizer, a pressure transformer is attached, which pre-compresses the vapors drawn off, thereby reducing the specific volume of the vapors.

In particular, the device is of such a type that the pressure transformer has an absorber in which the low-pressure vapors are mixed with and absorbed by an absorbent, a heat exchanger device for dissipating the heat of absorption, a pump device for taking vapor-enriched absorbent solution from the absorber and forwarding it to a heat exchanger a higher pressure and in a steam expeller to expel the steam under higher pressure from the absorbent.

Further details of the invention emerge from the subclaims.

In the following, the method and the device according to the invention are different. Applications in examples further explained with reference to the drawings. In it represent:

FIG. 1 shows a graphic representation of the principles according to the invention,

FIG. 2, a process diagram for juice thickening,

Figure 3, a detail of Figure 2 (labeled "X"),

FIG. 4, a process diagram for the concentration of saline water,

Figure 5, a process diagram for the production of block and ice mash, FIG. 6 shows a process diagram of a pressure transformer, as can be used for example in the thickening of fruit juice or chemicals dissolved in water under triple point conditions, or for the production of ice or ice pulp, for example for cooling purposes.

FIG. 7, a process diagram for a complete plant for the production of an ice pulp for cooling purposes, including some of the characteristics described in connection with FIG. 5 and in combination with FIG. 6.

Reference is first made to Figure 1, which shows some of the principles of the invention in a graphical representation. The ordinate P represents the pressure and the Abzissae SV the specific volume.

In the graphic representation, the curve a, b never represents the van der Waalsche status line, consisting of the settling line a of the aqueous liquid, which rises to a maximum, represented by the critical point e, beyond which it becomes the dew line b. Another curve shows the states which are passed through by the aqueous liquid during the process, including point f, namely the state of the solution before entering the spray nozzles, from which the aqueous solution is injected into the evaporator, while part c of the curve shows the Represents the state of the droplets inside the evaporator. The dashed horizontal line represents the triple point pressure.

FIGS. 2 and 3 show a diagram of the process principles for the thickening of juice in a process according to the invention. In Figure 2, 1 represents the evaporator, in the form of a cylindrical container under reduced pressure. About halfway between the top and bottom of the Evaporator 1 is the injection system 2, which is supplied with the juice to be concentrated through a line 3 by means of the juice pump 4. The fresh juice is cooled in a juice cooler 5 in countercurrent to the melted ice and vapor condensate in a manner to be described below, and pressed through the nozzle system 2 by the pump 4. The nozzles 6 of the nozzle system 2 convert the juice into fine drops 7, which enter the evaporator at high speed. A reduced pressure is set in the evaporator, which theoretically corresponds to the triple point pressure of the solution to be thickened. Due to the short residence time of the drops, however, the equilibrium state of the triple point in the liquid jets 7 is not reached. Rather, there is a lively evaporation of the drops with strong hypothermia, which initially does not result in ice formation. For the formation of the disease, critical illnesses are necessary, which cannot be achieved due to the short dwell time (a few hundredths of a second). The state change during the flight time of the droplets never takes place along the van der Waals state line without reaching equilibrium, as shown in FIG. 1.

The nozzle system 2 is located in a manner far below the top of the vessel 1, where the vapors are suctioned off, preferably at least 1.5 m below the droplet separator 29 and even better 1.8 to 3 m. By comparison, the nozzles are quite close to the surface of the ice pulp, e.g. not more than about 2 m, in order to nevertheless provide a sufficient residence time for the evaporation. This distance can be significantly reduced, e.g. to less than 1.5 m if the nozzles are designed in such a way that wide-angle spraying takes place.

The drops 7 are collected in the evaporator sump. There will be the strong one through a sufficient stay Hypothermia is reduced by the formation of ice. The ice slurry produced in this way enters the separating apparatus 10 via a screw pump 9, which removes a bundle of perforated or porous tubes or plates 12. The tubes can also consist of wound screen mesh or supported separation membranes. Through the pores or openings of the ring 12, the diameter of the openings being adapted to the particle size of the ice crystals of the pulp 11, the thickened product (juice) 13 migrates into the outer space of the separating apparatus 10, formed by a jacket 14, and is there at 15 deducted. The ice content in the flow direction increases in the tubes, and then the ice reaches an equalization space 15, formed by a tube sheet 17 above the tubes 12, for the purpose of speed compensation. The ice is then washed in a washing column, which works in a similar way to the separating apparatus 10, in countercurrent to the melt water formed by the melting of the ice in the upper part of the device. The washing column has perforated or porous tubes 19, similar to the tubes 12 of the separating apparatus 10. This melt water serves as washing water and, with a low product content, passes through perforated tubes 19 of the washing column 18 into the outer space 20 of the washing column, filtered by the jacket 21, and wi rd then added through the outlet 22 and at the pipe connection 23 to the pre-cooled fresh juice before entering the pump 4.

Still moving upward, the ice enters the impermeable tubes 24 of the melting condenser 25, which is located in the material flow with and on the washing column 18, and liquefies by absorbing heat from the steam 26, which previously came from the evaporator 1 via a droplet separator or Demi ster 29 with the help of a compressor 27 to reduce the pressure within the evaporator 1 and to compress the vapors 26 to a higher pressure of the evaporated steam 28, which in the Melting condenser 25 enters through the nozzle 30, has been compressed. The condensate 31 of this steam is withdrawn from the melting condenser 25 through a nozzle 32, and conveyed by a pump 33 and added to the melted ice in the mixing chamber or mixing chamber 34. This mixing chamber 34 is constructed above and in the material flow of the melting condenser 25 and separates it from the juice artist above the mixing chamber 34. The condensate is used in the juice cooler 5 to cool the fresh juice. The washing device, ie the washing column 18, is separated from the melting condenser 25 by a tube plate 35 common to the tubes 19 and 24. The detail X in FIG. 2, which shows the relationship between the melting condenser and the washing column and the principle of action of the washing column, is shown in FIG. 3. The melt water serving as washing liquid is schematically represented by the meandering lines and arrows 36.

The juice cooler 5 has a casing 37 with inlet and outlet ports 38 and 39 for the fresh juice delivered by the feed pump 40. The cooler also has a bundle of vertical cooling tubes 41, through which the contents of the mixing chamber 34, which in the meantime have largely melted, migrate upward into a collecting chamber 42. This represents the top part of the device, of which the separator 10 forms the bottom part. Now that most of the cold has been released into the fresh juice, the water 43 is discharged through the water outlet 44.

The following example is intended to give you an impression of the size of the operator in the case of apple juice thickening.

Fresh juice entry temperature 20 ° C

Fresh juice concentration 8.3 Bx

Product outlet temperature 1 ºC Product concentration 48 Bx

Leaving water temperature 16 ° C

Concentration factor 5.8

Evaporator pressure 500 N / m ²

Pressure in the melting condenser 810 N / m ²

Energy requirement based on the amount of water expelled 13.6 kJ / kg

The very low energy requirement of 13.6 kJ / kg water is only 27% of a comparable evaporator system with vapor compressions that would work at 70 ° C.

With minor modifications, the described method can also be applied to other tasks. FIG. 4 shows a performance example for the concentration S a l z h a l t i g e r W a w s e r w i e A w a w s e r a u s flue gas desulfurization plants, mine water or cooling tower blowdown water. The same reference numbers are used to designate the same or essentially the same parts as those according to FIGS. 2 and 3.

In the present case, the nozzle 38 becomes an inlet for raw water, the juice cooler 37 becomes a raw water cooler and the line 3 for fresh juice now conveys pre-cooled water. The ice pulp 11 'in the present case differs from the ice pulp 11 which accumulates in the collecting space 8 of FIG. 2 in that it also contains salt crystals.

The ice pulp 11 "from the evaporator 1 is conveyed in the case of FIG. 4 by the screw pump 9 into a hydrocyclone 50. There, the precipitated solids are drawn off at 51 with the concentrate. Instead of a hydrocyclone, a centrifuge can advantageously be used, in particular The brine 15 'separated in the separating apparatus 10 is returned together with the washing water 36 into the area 8 of the evaporator 1. The other process steps remain as shown in FIG. 2 and described with reference to it.

Another application is the production of ice pulp and block eggs for cooling or egg production. The corresponding process scheme is shown in FIG. 5. Again, the same reference numerals apply to the designation of parts that are identical or essentially identical to those in FIGS. 2 and 3. The raw water 38 'is mixed with make-up water 38 "(see later) and passes through the nozzle system 2 into the evaporator 1, which works according to the same principle as shown in FIGS. 2 and 3. In this case, however, the steam produced can no longer be obtained from the egg The steam 26 is drawn in and earned by a multi-stage compressor 27 'via the droplet separator (demister) 29. Between the stages of the multi-stage compressor 27', cooling water 52 is injected into the steam stream, to reduce the specific volume and thereby to achieve a lower workload. A part 28 'of the compressed steam 28 is re-condensed in the condenser 53 and after softening at 54 is used again as injection water 52. The larger part 28 "of the steam is experienced by a Steam jet pump 55, driven by working steam 56, and is injected at 57 into a spray condenser 58 . The final pressure is selected so that the steam in the subsequent spray condenser 58 can condense on cooling water 59, which is supplied by a cooling tower 60. The inert gases 61 (non-condensable) leave the condenser 58 via a vacuum pump 62, which is followed by a smaller condenser 63 for the condensation of the residual steam.

The ice pulp 11 removed from the evaporator 1 via the screw pump 9 is freed of the brine 15 ″ in the separating apparatus 10 and produces the egg pulp for the eventuality The brine 15 "from the separating apparatus is partly sent back to the evaporator 1 at 64 and partly used for cooling the condensers 53, 63 for generating injection water 52 and residual steam condensation from the inert gases 61. If block ice is desired, the ice pulp runs through The pelletizer 66 and the pressed block ice 67 fall onto a conveyor belt 68 for transport for further use The residual water, (press water) 69 is used in this case for the cooling of the condensers 53, 63 for injection water and inert gases (dashed line) Brine 15 "emerging from the separator is then entirely returned to the evaporator 1 at 64. The additional water 38 "is required for the case if the raw water 38 'absorbs salts in upstream systems. The energy requirement of the system according to FIG. 5 was calculated to be about 60 kJ / kg, ie only 25% of the value of conventional systems for ice cream production lung.

If the ice pulp is intended as a final product for cooling purposes, in order to be pumpable, such a pulp must have an ice to liquid phase content of more than 50:50, in particular between 50:50 and 80:20, preferably about 70: Own 30. The slurry enriched in this way can be pumped to where cooling is required, e.g. for environmental cooling in underground mining. Compared to the conventional use of cold water, this method offers the advantage that the volume of the ice cream concentrate that has to be pumped in to a given location for a required cooling capacity corresponds to only a small fraction of the volume of cooling water that one can use for the same Purpose should have pumped.

Figure 6 shows the principle of the use of a pressure transformer according to the invention for converting low-pressure steam into steam at higher pressure, in particular for the purpose of reducing the size and thus improving the energy efficiency of compressor systems 27, 27 'as used in the examples in FIGS. 1 to 5.

Referring to FIG. 6, the vapor space 101 of a triple point evaporator (for example an evaporator as described with reference to FIGS. 1 to 5) and which serves as a freezing system 102 is connected to the absorption space 104 via a pipeline 103. This is a falling film absorber in a tube bundle design. From the mo bere n R o nr b ode n 105, the poor absorbent solution (with low water content) flows, delivered via a line 121 through distribution caps, not shown, which ensure uniform wetting, on the inside of the tubes 106 of the absorber (104 to 108) down. The resulting large surface area at high flow velocity absorbs the steam inside the absorber, so that a negative pressure is created and additional steam is thereby sucked out of the freezer 101. The heat released during absorption is removed by cooling water which flows through the jacket space of the absorber 104 (arrows 107). The, water-rich, absorbent solution flows from the lower opening of the tubes 106 into the sump 108 and is sucked off there by a pump 109. If there are inert gases that are not absorbed by the absorbent, they can be sucked off by a vacuum pump 110. The of the

Solution pump 109 sucked rich solution is pumped to the desired evaporation pressure and then heated in a tube bundle heat exchanger 111. It then flows into the steam expeller 112, which is designed as a film evaporator in a tube bundle design with tubes 113. The rich solution flows downwards on the inside of the tubes 113 in a falling film, as a result of which water from the medium water enriched on the inside of the Ronre 113 Absorbent solution partially evaporated and this water is withdrawn at 114 as steam of higher pressure. This vapor of higher pressure is passed through a vapor compressor 115 and is fed at 116 to the top of the casing space around the ring 113 so that the previously vaporized and compressed vapors condense on the outside of the tubes 113. Due to this construction and operating mode, it is possible to work with very low temperature differences and high heat transfer coefficients.

The condensate of the compressed steam collects on the lower tube plate 117 in the jacket space and is drawn off at 118. His remaining energy can be used elsewhere in the process. The poor solution which has flowed into the sump 119 of the steam expeller on the inside of the pipes 113 flows further into the previously mentioned tube bundle was a heat exchanger 111, where it is cooled by the water-rich solution. It then continues to flow through a throttle valve 122 into the upper part of the absorber 104.

The following example is intended to give an impression of the process sizes for the use of lithium bromide / water as an absorbent:

Amount of steam absorbed 0.41 kg / s

Specific volume of the steam 224 m ² / kg

Concentration of the rich solution 0.487 kg H ₂ O / kg solution

Temperature of the rich solution in the

Absorber sump 23.5 ° C

Pressure in the expeller sump 0.2 bar

Specific volume of steam in front of the compressor 7.5 m ² / kg

Pressure after mechanical compression 0.84 bar

Concentration of poor solution 0.47

Poor solution temperature at Absorber entry 24 ºC mass flow of poor solution 12.48 kg / s

In FIG. 6, area I on the left side of the dash-dotted line A represents the pressure transformer stage according to the invention. Area II on the right side of line A represents the part of the system with the mechanical compressor 15, the size of which to improve the overall thermal efficiency of the process intended for area II.

In the present method, the area II includes a precaution, since the switch to the triple point evaporator 102, e.g. the evaporator 1 in Figure 5, which is supplied by a Ronwasserpump 123 with raw water via a line 124. If necessary, this Ronwasser can be supplemented with additional water (not shown). The water is injected through nozzles of a spray system 125 into the interior of the evaporator 102, which is kept under low pressure by the negative pressure formed in the region I, as a result of which partial evaporation of the droplets formed in the spray system 125 occurs. The low pressure nozzles formed represent the vapors which are withdrawn from the vapor space 101 through the line 103. The evaporation causes hypothermia of the droplets below the freezing aperture, and partial freezing takes place in the sump 126 of the evaporator 102. This creates an ice pulp, the liquid phase of which contains all the solids contained in the raw water (e.g. fruit juice, waste water, cooling tower drain water) in a concentrated form. This ice slurry in the aqueous concentrate is drawn off at 127 for further use and processing, e.g. in a further detail for FIGS. 1 to 5 described.

As for Figure 7, there are those of Figures 2 to 5 corresponding parts with the same reference numerals as in these figures, while the parts corresponding to the parts according to Figure 6 are correspondingly provided with the reference numerals as in Figure 6.

According to FIG. 7, water for the production of an ice pulp for cooling purposes is withdrawn from a water reservoir 150 and first pumped through a pre-cooling tower 151 and pressed from there by means of a pump 152 and via a down pipe 153 into the spray system 2, which has spray nozzles 6 directed upwards, to avoid pressure losses which are attached just below the top of the ice slurry 11 contained in the sump of the freeze evaporator 1. Since the pump 152 is designed to supply the pipe water 38 'with a constant delivery rate, which often exceeds the supply consumption of the spray system 2, a bypass pipe 154 is also provided, whereby the menranfall of water is returned to the reservoir 150. In the evaporator there is an ice scooping device 156, which floats on the surface of the ice pulp, and the hone of which is thus in a fixed ratio to the ice brewing level in the device, this level being monitored by a control device 157.

Ice pulp 11, which accumulates in the bottom part of the evaporator, is subject during its dwell time to a partial separation of gravity into ice particles which float upwards and the liquid phase which sinks under gravity and which, together with suspended and precipitated solids, accumulates in the liquid phase in the downpipe 158, the bottom End has a drain valve 159 through which solid precipitates can be removed as sludge at intervals. Concentrated egg pulp is skimmed off by mechanical stripping devices as part of the skimming device 156 from the surface of the egg pulp into the hopper of the skimming device 156 and arrives from there through a flexible line 160 and the tube 161 into the centrifugal ice concentrator 50 'from where a concentrated ice slurry is drawn off through line 122 to the screw pump 9 and is conveyed from there in the direction of arrow 163 to any location where cooling is to be carried out, for example in the sam mena ng mit t u terta ge be r gba u. D ieim

Centrifugal ice separator liquid phase is withdrawn through a pipe 164 by means of a pump 165 and fed to a further nozzle system 2 ', which is also equipped with upwardly directed spray nozzles below the surface of the ice slurry in the evaporator. The nozzles of the spray systems 2 and 2 'thus spray an upward sprinkling of water and brine into the evaporator chamber 1. The nozzles are about 10 to 100 mm below the surface. The arrangement of the nozzles below the surface of the ice slurry counteracts the tendency of the nozzles to freeze, and the upward spraying also somewhat extends the floating time of the droplets in the vacuum space. The falling, cooled droplets have a lower solute content than that of the liquid pnase in the ice pulp and thus partially prewash the ice concentrate.

Redirection devices 167 serve to bypass the cyclone or the centrifuge in the start-up phase of the system before ice has formed, or to redirect the liquid phase into the bottom of the evaporator without being passed through the spray system 2 '.

The vapors that have to be withdrawn from the evaporator room 1, you give to the next case if a new pack 29 'is provided for the time being

Teardrop cutting, but this can be dispensed with if the vaporizer space above the nozzles is of sufficient height, for example 2 to 5 m, in particular about 3 m, before the vapors through the trough cutting device 29 and in the vapor line 26, and from there into the upper end of the absorber 104-108. Coolant lines 107, which lead from a condenser tower 107 'and back again, are used to cool the pipes 106 of the absorber. From the sump 108 of the absorber, the water-enriched absorption medium solution is fed by a pump 109 to a first heat exchanger 111 ', where it is heated by hot, low-water absorption medium solution, which is extracted from the sump 119 of the steam expeller 112 via a line 110. It absorbs further heat in a second heat exchanger 111 ″, supplied by the compressed vapors and the condensate, which are passed through the jacket surrounding the steam discharge pipes 113. This condensate, with a low content of total dissolved solids, is added partial release of its heat content in the heat exchanger 111 "through the line 121 'is returned to the water reservoir 150 for reuse in the process.

The steam chamber 108 'of the sump 108 of the absorber at 171 removed water vapor passes into a cold trap 110', which is evacuated via a venting element 110 "by a liquid vacuum pump 110. The heat exchange tubes of the cold trap 110 are cooled by cold liquid phase which was withdrawn from the downpipe 153 of the evaporator via the pump 172 and a line 173 and, after passing through the cooling trap at 174, enters a heat exchanger 175 and from there through line 176 of a conductivity tsmessgerät 178 and a signal transmitter 179 monitored three-way control elements 177. Until the conductivity of the solids content of the liquid phase extracted from the downpipe 158 reaches a predetermined upper limit, the liquid is returned to the bottom of the evaporator via a nozzle 180 directed downwards a mixture in the egg pulp and washes solid Precipitation from the inclined sump wall down and down into the downpipe 158, where it is finally drawn off through the valve 159. As soon as the predefined solids content is exceeded, a signal emitted by the device 178, 179 causes the liquid to be discharged via the three-way valve 177 via a waste water line 181 for disposal. The wastewater volume derived at 181 represents only a very small percentage of the total amount used of the aqueous liquid extracted from the reservoir 150.

In order to come back to the liquid ring vacuum pump 110, this is used to extract non-condensable gases through the defog element 110 "

Cooling liquid for the pump 110 is circulated by a pump 182.

In order to come back to the steam expeller 112 again, the vapors expelled by heating from the absorbent solution in the runners 113 collect in the steam space 119 'above the liquid level kept constant in the sump 119 by means of the circulation line 120' and the monitoring devices 120 ", which level is thereby maintained is that, as required, liquid is returned from line 120, which draws water-free absorbent solution from sump 119 via pump 183 and passes back through heat exchanger 111 "via line 121 into the absorber. The vapors in the space 119 'of the sump 119 enter the suction side 184 of a multi-stage compressor 115 through a defogger element 119 ". Cooling water, which is removed from the sump of the cold trap 110" via a condensate pump 185, is controlled to a controlled extent by means of the spray devices 52 the stages of the multi-stage compressor injected. The extent of the injection can optionally be controlled by a control element 186 controlled by a guide plate, and excess cooling water is returned via line 187 to cold trap 110 '. Part of the cooling water is injected at 188 for injection into the labyrinth seal on the top of the compressor, below the gear 189 to improve the seal.

The following claims are to be considered an integral part of the present disclosure. Reference signs (referring to the drawings) that appear in the claims serve to facilitate the comprehensibility of the claims, but are not intended to limit the meaning of the claims to the content of the drawings unless the opposite is clear from the context.

Claims

EXPECTATIONS

1. A process for converting an aqueous liquid into an egg pulp with subsequent subsequent treatment of the ice slurry, characterized in that the liquid is injected into an evaporator chamber, which is expanded to a pressure which corresponds to the saturation pressure at the corresponds to the corresponding evaporation temperature of the liquid in the evaporation chamber at -5 to + 10 ° C, so that the liquid partially evaporates due to a phase imbalance caused by a short residence time in the evaporation room and thereby cools down to a low temperature and is then collected with a sufficiently long residence time , so that due to an equilibrium which is established, an ice pulp forms, the ice pulp is drawn off and is subjected to a separation of the liquid phase from the ice pulp, followed by one or more of the following process steps:

a) obtaining a concentrate of the aqueous liquid,

o) obtaining or removing substances dissolved in the aqueous liquid in precipitated or other phase-separated form,

c) Obtaining the ice as concentrated ice pulp or as solid blocks or pellets.

2. The method according to claim 1, characterized in that the liquid spray into the evaporator chamber takes place relatively close to the surface of the ice slurry collected in the room and in a considerable amount Distance to the top of the evaporator chamber, where the vapors are suctioned off after the droplets have been largely separated.

3. The method according to claim 1 or 2, characterized in that the vapors are sucked off after one pass through a denoiling direction.

4. The method according to any one of claims 1 to 3, characterized in that substances which are contained or dissolved in the aqueous liquid, in particular fruit juices, organic or inorganic acids, chemicals, waste water, in concentrated form in or out of the liquid part of the Ice porridge can be obtained.

5. The method according to claim 4, characterized in that the ice pulp is separated into a concentrated solution and a mixture of ice and solution.

6. The method according to claim 4, characterized in that the ice cream is concentrated and a brine is removed.

7. The method according to any one of claims 1 to 6, characterized in that the ice pulp is subjected to a partial gravity separation of the liquid from the egg sim evaporator space and the ice pulp is removed from the area of the top of the pulp in the space where the ice to liquid ratio is closest.

8. Verkanren according to claim 7, characterized in that the ice pulp is skimmed mechanically in concentrated form from the surface area.

9. The method according to any one of claims 1 to 8, characterized in that the liquid injection in the Evaporator space takes place in the upward direction from below the surface of the ice slurry accumulating in the space.

10. The method according to any one of claims 1 to 9, characterized in that the aqueous liquid is pre-cooled before being introduced into the spray system.

11. The method according to claim 10, characterized in that the pre-cooling takes place in countercurrent to the coolant.

12. The method according to claims 10 or 11, characterized in that melted ice from the ice pulp is used as the coolant.

13. The method according to one or more of claims 1 to 12, characterized in that the ice pulp is separated into ice and residual liquid and part of the ice is melted and used for washing the remaining ice and the washing liquid is returned to the evaporator space.

14. The method according to one or more of claims 1 to 13, characterized in that the vapors formed during the evaporation are compressed.

15. The method according to any one of claims 1 to 14, characterized in that vapors of the liquid evacuated and compressed from the evaporator space and the compressed vapors are continued so that they give off heat to the ice cream coming from the ice cream, thereby melting the ice bring, and condense itself.

16. The method according to claim 15, characterized in that the ice is washed before the heat is transferred from the vapors.

17. Verkanren according to claim 15 or 16, characterized characterized in that the vapor condensate is brought together with the melted ice and is thus used together for the pre-cooling of the solution to be concentrated.

18. The method according to claim 17, characterized in that the vapors are compressed in several stages and a coolant is injected after each stage.

19. The method according to claim 18, characterized in that part of the compressed vapors are used as the coolant, which were condensed before the injection and removed from a softening treatment.

20. The method according to claim 18 or 19, characterized in that the residual vapors by means of a steam jet device further compressed and fed to a condensation stage.

21. The method according to claim 20, characterized in that the condensate withdrawn from the spray condensation is returned to the spray condensation stage via a coolant.

22. The method according to claim 18 and 19, characterized in that a part of the brine removed from the separation apparatus is used for the condensation of the vapors intended for the injection.

23. The method according to claim 6, characterized in that part of the brine removed from the separating apparatus is added to the ice pulp formed.

24. The method according to claim 6, characterized in that the concentrated ice pulp is pelleted and the residual water formed is returned.

25. The method according to one of the preceding claims, characterized in that the ice pulp is used for cooling purposes.

26. The method according to any one of claims 1 to 3, characterized in that the ice pulp removed from the evaporator chamber is first thickened before it is used as a coolant.

27. The method according to claim 26, characterized in that the ice pulp is thickened to a pumpable ratio of ice to the liquid phase and pumped to a location where cooling is to take place.

28. The method according to claim 27, characterized in that the ratio of ice to the liquid phase is from 50:50 to 80:20, in particular about 70:30.

29. The method according to any one of claims 25 to 28, characterized in that the ice pulp is used for cooling in underground mining.

30. The method according to any one of claims 1 to 29, wherein the vapors sucked out of the evaporator chamber are converted into vapor at higher pressure before mechanical dilution, characterized in that the low pressure mixes with an absorbent in an absorber and is absorbed thereby wi rd, whereby the heat of absorption is removed by a coolant, in particular cooling water, and the absorbent solution enriched with liquid from the steam, in particular water, is first heated by heat exchange after a pressure increase by pump action and then passed through a steam expeller , where as a result of the heat absorption a vapor of higher pressure is formed.

31. A method for converting a low-pressure steam into a steam at a higher pressure by means of a pressure transformer stage, characterized in that the low-pressure steam is mixed in an absorber with an absorbent and is absorbed by it, the heat of absorption by means of a cooling means, in particular cooling water, is discharged and the absorbent solution enriched with liquid removed from the steam, in particular water, is first heated by heat exchange after an increase in pressure by pump action and then passed into a steam expeller, where a steam of higher pressure is formed.

32. The method according to claim 30 or 31, characterized in that the steam formed in the steam expeller of higher pressure is earned by means of a compressor and fed to a boiler room of the steam expeller, where it serves as a heating medium, which condenses sound heat after its condensate has been released , and then I leave the steam expeller.

33. The method according to any one of claims 30 to 32, characterized in that the absorbed solution of absorbed steam, in particular water, in the steam expeller is used in a heat exchanger for heating the steam-enriched solution from the absorber and then via a throttle valve is fed to the absorber.

34. The method according to any one of claims 30 to 33, characterized in that the inert gases released in the absorber are collected and sucked off via a vacuum pump.

35. Device for performing a method according to one of the preceding claims and with inclusion the characterizing part of claim 1, characterized by a vaporizer, for ice-cream formation with a vessel which has a nozzle system (2) approximately between middle and top and a nozzle system (2) in the lower area and a seed sump (8) and also beimo Ren B e rei ch vapor suction devices (26, 27) and in its lower part (8) an ice sludge removal and conveying device (9, 156), connected in series with devices (50 ', 10, 13) for further treatment of the ice slurry (11) .

36. Device according to claim 35, characterized in that the nozzle system (2, 2 ') is reasonably close to the ice mash surface in the evaporator (1), and the upper end of the evaporator is located high above the nozzles to enable the droplets to largely precipitate (7) from the steam to be extracted.

37. Device according to claim 35 or 36, characterized in that a droplet separator device (29) is connected upstream of the vapor suction device.

38. Device gei.iäss one of claims 35 to 37, characterized in that the ice pulp extraction device has a screw pump (9).

39. Device according to one of claims 35 to 33, characterized in that the devices for treating the ice slurry contain a separating device (50, 50 ', 10) for separating the liquid phase of the slurry from the egg.

40. Device according to claim 39, characterized in that the separating device (10) has a vessel with an upper and lower tube bottom, into which a tube bundle (12) made of porous material such as membrane or wire mesh is inserted and the bottom tube plate an entrance chamber with an entrance for receiving the ice slurry to be conveyed into the tube bundle is assigned, while a chamber (16) is provided above the upper tube sheet for receiving the treated slurry (11) enriched with ice.

41. Device according to one of claims 35 to 40, characterized in that it is set up for the production of an ice-enriched ice pulp with pumpable consistency, suitable as a coolant.

42. Device according to one of claims 38 to 41, characterized by means for increasing the ratio of ice to liquid in the ice pulp with a hydrocyclone (50).

43. Device according to one of claims 38 to 40, characterized in that a hydrocyclone is connected upstream of a separation device (10) according to claim 34.

44. Device according to one of claims 35 to 40, characterized in that the device for treating the ice slurry (11) includes a washing device (18) which is designed to wash out components of the aqueous liquid from the ice particles of the ice slurry.

45. Device according to claim 44, characterized by devices (22, 23) for combining the washing liquid extracted from the washing device (18) with the aqueous liquid introduced into the evaporator (1).

46. Apparatus according to claim 44 or 45, characterized in that the washing device (18) is tubular, with rings (19) made of porous material through which the ice pulp (11) is passed, surrounded by one Jacket (21).

47. Device according to claim 46, characterized in that the washing device (18) has a central intermediate groove (35) which, together with an upper and a lower base, forms an upper and a lower chamber, the tubes (19) of the lower chamber consist of porous material such as membrane or mesh, surrounded by a casing (21) with an outlet connection (22) for washing liquid, whereas the upper chamber in a similar way comprises the casing with an inlet connection (30) and an outlet nozzle (32).

48. Device according to claim 47, characterized in that the tubes (24) of the upper chamber are liquid-impermeable, and the upper chamber (25) constitutes a cooling condenser for compressed steam (28) from the evaporator (1), causing partial melting of the egg in the ring (24) for supplying the washing liquid for washing the ice particles in the washing column (18).

49. Device according to one of claims 44 to 48, characterized by a heat exchanger (37) which is connected downstream of the washing device (18) in the conveying direction of the ice slurry and is used for pre-cooling the aqueous liquid supplied to the evaporator.

50. Device according to one of claims 47 to 48 and claim 49, characterized in that the heat exchanger (37) is located on the washing device (18).

51. Device according to claim 47, 48 and 50, characterized in that the upper chamber acts as a cooling condenser (25), with a downstream mixing chamber (34) between the cooling condenser (25) and the heat exchanger (37). and is connected to the outlet port (32) of the upper chamber (25) for the introduction of compressed steam condensate into the mixing chamber (34).

52. Device according to claim 40, characterized in that the chamber (16) above the upper tube sheet is followed by the washing device (18), and the further devices according to claims 44 to 51.

53. Device according to one of claims 35 to 52, characterized in that between the steam extraction point (101, 103) and a mechanical compressor (115) for compressing the vapor extracted from the evaporator (102), a pressure transformer (I) is switched on a pre-thinning of the extracted steam causes, which reduces the specific volume of the steam.

54. Device according to claim 53, characterized in that the pressure transformer (I) has an absorber (104-108), whereby the low pressure steam (103) is mixed with and absorbed by absorbent (122), heat exchanger devices (106 , 107) for extracting heat of absorption, pump devices (109) for removing vapor-laden absorbent solution from the absorber and introducing them into a heat exchanger (111) at higher pressure and into a steam expeller (112) for releasing steam at higher pressure, at (114) from the absorbent.

55. Device for converting low-pressure steam into higher-pressure vapors, characterized by an absorber (104-108), in which the low-pressure steam (103) is mixed with an absorption medium (122) and is absorbed thereby, heat exchange devices (106, 107) for removing heat of absorption , Pump devices (109) for removing the vapor-laden absorbent solution from the absorber and its return into a heat exchanger (111) at higher pressure, and into a steam expeller (112) for

Release of steam (115) from the absorbent under higher pressure.

56. Device according to claim 54 or 55, for converting water vapor of low pressure into water vapor at higher pressure, characterized in that LiBr, NaOH, Ca (OH) ₂ , MgCl ₂ , CH ₂ NH ₂ or CaCl _{2 is} used as the absorbent.

57. Device according to one of claims 54 to 56, characterized by a compressor (115) for compressing the vapors supplied by the steam expeller (112), higher pressure, and a heating chamber (117) of the steam expeller, which absorbs the vapors (116) thus compressed mmt, which condense and give off condensation heat to the loaded absorbent.

58. Device according to one of claims 51 to 54, characterized by a heat exchanger (111) which is arranged to ensure that the absorbent solution (120) which is emaciated in the steam expeller (112) with regard to the absorbed steam absorbs the one coming from the absorber steam-enriched solution is heated, and then returns to the absorber (121, 122).

59. Device according to Claim 58, characterized by a throttle valve (122) through which the absorbent is returned to the aosorber (104).

60. Device according to one of claims 35 to 54, characterized by removal devices (156) for ice mash (11) in a region of the evaporator (1) in the area of the ice mash surface (11) in the evaporator.

61. Device according to claim 60, characterized in that the removal device (156) has a mechanical skimmer.

62. Device according to Ansrucn 60 or 61, characterized in that the level of the removal device (156) adapts to the ice level in the evaporator.

63. Device according to claim 62, characterized in that the removal device (156) is designed to float on the ice pulp.

64. Device according to one of claims 35 to 54 or 60 to 63, characterized in that the nozzle system (2, 2 ') has upwardly directed nozzles (6) below the normal surface of the ice slurry (11).