WO2007099041A1 - Milieux de travail pour des processus de refroidissement - Google Patents

Milieux de travail pour des processus de refroidissement Download PDF

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Publication number
WO2007099041A1
WO2007099041A1 PCT/EP2007/051508 EP2007051508W WO2007099041A1 WO 2007099041 A1 WO2007099041 A1 WO 2007099041A1 EP 2007051508 W EP2007051508 W EP 2007051508W WO 2007099041 A1 WO2007099041 A1 WO 2007099041A1
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polymer
oligomer
refrigerant
working
working pair
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PCT/EP2007/051508
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German (de)
English (en)
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Matthias Seiler
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Evonik Degussa Gmbh
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    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
    • C09K5/00—Heat-transfer, heat-exchange or heat-storage materials, e.g. refrigerants; Materials for the production of heat or cold by chemical reactions other than by combustion
    • C09K5/02—Materials undergoing a change of physical state when used
    • C09K5/04—Materials undergoing a change of physical state when used the change of state being from liquid to vapour or vice versa
    • C09K5/047—Materials undergoing a change of physical state when used the change of state being from liquid to vapour or vice versa for absorption-type refrigeration systems

Definitions

  • the present invention relates to new pairs of work for refrigeration processes and / or refrigeration machines. More specifically, the invention describes the use of preferably branched, oligomeric or polymeric substances as an additive or sorbent for refrigeration processes. The use of the substances according to the invention as an additive or sorbent leads to improvements in the properties of the working couple. In addition, the invention includes novel process variants for refrigeration processes with advantages over the prior art.
  • a chiller or heat pump based on the circulation of a working medium (also referred to as refrigerant), wherein at different pressure levels heat is added or removed.
  • refrigerant also referred to as refrigerant
  • the basic principle is through a so-called counter-rotating Clausius Rankine process described and thus represents a direct reversal of a heat engine.
  • the refrigerant passes through the steps of (a) compression, (b) condensation, (c) relaxation and (d) evaporation.
  • Warmth is raised from a lower to a higher temperature level.
  • the aim here is to lift a large amount of heat to a higher temperature level and dissipate there with a given amount of mechanical, electrical or thermal energy. In this case, it is possible to realize the change of the temperature or pressure levels by one or more stages.
  • chillers The difference between chillers and heat pumps results from the temperature level used.
  • the heat (usually at the condenser) at a high temperature level is generated, e.g. used for heating purposes, while in a chiller, the heat to be supplied (usually to the evaporator) is used for Kuhl format.
  • Heat pumps can also be designed in the form of high-temperature condensing technology, the
  • Condensation heat of the water vapor contained in flue gases is used above the Rauchgastauorgans.
  • part of the water vapor in the exhaust gas is taken up in an absorber by a hygroscopic wash solution (eg LiBr solution) and then expelled again in a desorber at a higher temperature.
  • a hygroscopic wash solution eg LiBr solution
  • Both from cooling and condensation of the expelled water vapor, as well as from the Cooling the wash solution before returning to the absorber resulting heat can now be used at a high temperature level.
  • Compression chillers characteristically perform the cycle illustrated above using mechanical compressors. These compress the refrigerant, which is at least partially vaporous or supercritical.
  • Steam jet refrigerators have steam jet compressors instead of mechanical compressors and use water as a refrigerant. They evaporate a part of the water at low working pressure and extract the heat of vaporization from the residual water, which can be used as a refrigerant. Steam jet cooling plants can also be designed as open processes.
  • thermal compression alternative compression
  • This consists of the absorption of the vaporous refrigerant in an absorbent, the compression of the resulting liquid mixture and a subsequent supply of heat to expel the refrigerant at a high pressure level.
  • Absorption refrigerating machines are based on the use of a so-called work pair or working substance pair, consisting of a refrigerant and a
  • Sorbent also called absorbent, absorbent or Absorptionskol.
  • the sorbent must be liquid in continuously operating sorption refrigeration machines, the concentration of the refrigerant in the sorbent
  • Absorption liquid is dependent on the absorption capacity, the pressure and the temperature. Within the pressure and temperature range that refrigerant and sorbent undergo in sorption refrigeration machines, both substances must be miscible, with no
  • the working couple can also be mixed with one or more additives with the aim of improving the absorption capacity, the heat capacity or the heat transfer and the solidification temperature of the Häsparlosung and
  • a beneficial working couple should be chemically and thermally stable, non-toxic, non-flammable, non-environmentally hazardous and non-corrosive.
  • the working medium is understood in the context of this invention, occurring at least at one point of the refrigeration process maximum number of system components.
  • the working medium is thus a mixture consisting of the working pair (that is to say a system of sorption substance and refrigerant) or working pair and, if appropriate, additions of additives.
  • the working pair that is to say a system of sorption substance and refrigerant
  • working pair that is to say a system of sorption substance and refrigerant
  • additions of additives for compression refrigeration systems,
  • Heat pump systems or other cooling processes should be understood in the context of this invention as a working medium or working pair of that mixture in the
  • Compressor is compressed, preferably a mixture consisting of a refrigerant and at least one additive, such. a lubricant for the compressor.
  • additives may be added as described in Kim, J. -S. et al., Applied Thermal Engineering 19 (1999) 217-225 or Glebov, D. and Setterwall, F., International Journal of Refrigeration 25 (2002) 538-545 or Ziegler, F. and Grossman, G., International Journal of Refrigeration 19 (1996) 301-309.
  • WO97 / 49781 discloses a coolant working fluid containing at least one dendritic or hyperbranched polyester macromolecule and at least one chlorofluorocarbon coolant such as difluoroethane, trifluoroethane, tetrafluoroethane or pentafluoroethane.
  • N, N-dimethylformamide typically have significant volatility which, when the concentration of the sorbent is high, leads to contamination of the refrigerant, necessitating the installation of further separation equipment downstream of the extruder.
  • the return of insufficiently concentrated sorption of the expeller back to the absorber is disadvantageous, since the sorbents there can therefore accommodate only correspondingly small amounts of refrigerant and thus undesirable large and energetically adverse recirculation flows arise.
  • the object of the present invention was to find working couples which are suitable for use in refrigeration processes and / or refrigerating machines, in particular in absorption heat pumps, absorption refrigerating machines, steam jet refrigerating machines, compression refrigerating machines and / or heat transformers, and the at least one of the stated disadvantages, preferably as many of the disadvantages mentioned , not show. Furthermore, it was the object to find an absorbent having a sufficiently low vapor pressure in order to avoid problems in the separation of substances as possible, is stable at the expected temperatures, with the refrigerant such. Water,
  • Ammonia or trifluoroethanol as good as possible miscible and can absorb it in a suitable manner.
  • the oligomer or polymer has a solubility in the refrigerant at 50 0 C of at least 1.0 g, based on 100.0 g of refrigerant , and (iv) the solution viscosity of an oligomer refrigerant solution or a polymer refrigerant solution containing 10.0 wt .-% oligomer or polymer, measured according to DIN 53019 at 60 0 C with a shear rate of 50 Hz, less than 700 mPas, preferably less than 500 mPas and more preferably less than 200 mPas, wherein the
  • Solution viscosity is preferably determined using the RheoStress® 100 of the company ThermoHaake, it is not possible to predict a highly efficient working pair in a manner which can not be foreseen without further ado which in particular has an improved absorption behavior in refrigeration processes and / or refrigerating machines, viz. a. in adsorption heat pumps, absorption refrigerating machines, steam jet refrigerating machines, compression refrigerating machines and / or heat transformers,
  • the working group according to the invention contains at least one refrigerant, the refrigerant, based on its total weight, not more than 1.0 wt .-%, particularly preferably at most 0.1 wt .-%, in particular no,
  • Halogen-containing hydrocarbons having a boiling point less than 70 0 C, each measured as a pure substance at 101325 Pa includes.
  • the halogenated hydrocarbons include, inter alia, difluoroethane, trifluoroethane, tetrafluoroethane and pentafluoroethane.
  • refrigerants for the purposes of the present invention are those which absorb heat in a refrigeration system by low temperature, low pressure evaporation and release heat by liquefaction at higher temperature and pressure. They are specified in greater detail in DIN 8962 of August 1968 ("Refrigerants").
  • the refrigerant conveniently has one
  • Evaporation enthalpy ⁇ 300 kJ / kg, particularly preferably> 350 kJ / kg, on.
  • water, methanol, ammonia, trifluoroethanol preferably linear hydrocarbons, in particular ethane and propane, and alkylamines, in particular methylamine, dimethylamine and ethylamine.
  • a refrigerant with a water solubility of at least 1.0 g, preferably at least 5.0 g, more preferably at least 10.0 g, in particular at least 20.0 g, each based on 100.0 g of water, measured at 25 ° C. , and especially proven against all water, trifluoroethanol and / or ammonia.
  • alkanes in particular ethane and / or propane, are used as the refrigerant.
  • the refrigerants can each be used individually or else as a mixture of two or more of the abovementioned components.
  • the working pair according to the invention furthermore contains at least one preferably branched oligomer or polymer.
  • oligomer is understood to mean a molecule having from two to eight identical or similar, preferably identical, repeat units
  • polymer means a macromolecule having more than 8 identical or similar, preferably identical, repeat units.
  • the working pair contains at least one, preferably branched, Polymer.
  • Particularly preferred polymers include hyperbranched polymers and hyperbranched macromolecules with a smaller degree of branching than hyperbranched polymers.
  • dendritic polymers Highly branched, globular polymers are also referred to in the literature as "dendritic polymers.” These dendritic polymers synthesized from multifunctional monomers fall into two distinct categories, the
  • Dendrimers and the “hyperbranched polymers”. Dendrimers have a very regular, radially symmetric generation structure. They represent monodisperse globular polymers, which are produced in multistep syntheses with a high synthetic effort compared to hyperbranched polymers. The structure is characterized by three different areas: - the polyfunctional nucleus, which represents the center of symmetry, - various well-defined radial symmetric layers of one
  • the hyperbranched polymers in contrast to the dendrimers, are polydisperse and irregular in their branching and structure. In addition to the dendritic and terminal units, in hyperbranched polymers, linear units also occur - in contrast to dendrimers. 1 shows in each case an example of a dendrimer (1) and a highly branched polymer (3), constructed from repeating units (2), which each have at least three bonding possibilities.
  • a) Frechet JMJ Tomalia DA "Dendrimers And Other Dendritic Polymers” John Wiley & Sons, Ltd., West
  • the hyperbranched and highly branched polymers described in these publications are also preferred sorbents for the purposes of the present invention.
  • the hyperbranched polymers have at least 3 repeat units per molecule, preferably at least 10 repeat units per molecule, more preferably at least 100 repeat units per molecule, more preferably at least 200 repeat units, and still more preferably at least 400 repeat units, each at least three , preferably at least four bonding options, wherein at least 3 of these repeat units, more preferably at least 10 and more preferably at least 20 each have at least three, preferably at least four bonding options with at least three, preferably at least four further repeat units are linked.
  • the hyperbranched polymers have a maximum of 10,000, preferably a maximum of 5,000 and more preferably a maximum of 2,500 repeat units.
  • the hyperbranched polymer has at least three
  • Repeat units each having at least three possible binding possibilities, wherein at least three of these repeat units have at least two possible binding possibilities.
  • repeating unit is to be understood as meaning an always recurring structure within the hyperbranched molecule.
  • the term “possibility of bonding” is preferably understood as meaning the functional structure within a repeating unit with which a link to another repeating unit is possible. Based on the above examples of a dendrimer or hyperbranched polymer, the repeating unit is a structure with at least three bonding possibilities (X, Y, Z):
  • the linking of the individual bonding units with one another can be achieved by polycondensation, by polyaddition, by radical polymerization, by anionic polymerization, by cationic polymerization
  • Polymerization by group transfer polymerization, by coordinative polymerization or by ring-opening polymerization.
  • the oligomer or polymer has a solubility in the refrigerant at 50 ° C. of at least 1.0 g, preferably at least 5.0 g, more preferably at least 10.0 g and in particular at least 20.0 g, in each case based on 100.0 g refrigerant.
  • the oligomer or polymer is soluble in water, the water solubility at 70 ° C. suitably being at least 1.0 g, preferably at least 5.0 g, more preferably at least 10.0 g and in particular at least 20.0 g, in each case based on 100.0 g of water.
  • the oligomer or polymer is soluble in trifluoroethanol, wherein the solubility in trifluoroethanol at 50 0 C expediently at least 1.0 g, preferably at least 5.0 g and more preferably at least 10.0 g , in each case based on 100.0 g of trifluoroethanol.
  • the substance solids must be pulverized
  • the solution is cooled and held at the test temperature. The solution is stirred until the equilibrium is reached. Alternatively, the measurement can be performed immediately at the test temperature, if it is ensured by appropriate sampling that the saturation equilibrium is reached. Then the concentration of the test substance in the solution, which must not contain any undissolved substance particles, is determined by a suitable analytical method.
  • the working pair contains at least one hyperbranched oligomer or polymer comprising polyether, polyetheramide, polyetherimide, polyethersulfone, polyester, polyesteramide, polyesterimide, polyamide, polyamidoamine, polyimideamine , Polyurethane, polyurea, polyureaurethane, polyglycerol,
  • the oligomer or polymer expediently contains 2 to 10,000, preferably 2 to 5,000 and particularly preferably 2 to 3,000 of these units.
  • the oligomer or polymer has a core-shell structure, wherein the core and the shell are each made up of different repeating units.
  • polymers having a core comprising polyethyleneimine units and a shell comprising polyether units have proven particularly useful.
  • the working pair contains at least one polyamide graft copolymer which preferably contains units of the following monomers: a) 0.5 to 25% by weight, based on the graft copolymer, of a polyamine having at least 11 nitrogen atoms and a number average molecular weight Mn of at least 500 g / mol; b) polyamide-forming monomers selected from di-, tri- and / or oligoamines, lactams and ⁇ -aminocarboxylic acids and / or di-, tri- and / or oligocarboxylic acids and mixtures of said compounds.
  • the working pair comprises at least one polyether graft copolymer which preferably contains units of the following monomers: a) 0.5 to 25% by weight, based on the graft copolymer, of a polyamine having at least 11 nitrogen atoms and a number average molecular weight Mn of at least 500 g / mol; b) a combination of ethylene oxide and propylene oxide as polyether-forming monomers, wherein the proportion of ethylene oxide between 0 and 100.0 wt .-%, based on the polyether structure, may vary.
  • the oligomer or polymer according to the invention has a weight average molecular weight M w in the range of 300 g / mol to 50,000 g / mol, favorably in the range of 300 g / mol to 45,000 g / mol, particularly preferably in the range of 300 g / mol 40,000 g / mol, in particular in the range of 300 g / mol to 20,000 g / mol.
  • the determination of the molecular weight in particular the determination of the weight average molecular weight M w and the number average molecular weight, can in known manner, for. B. be measured by gel permeation chromatography (GPC), wherein the measurement is preferably carried out in DMF and polyethylene glycols are preferably used as a reference (see, inter alia Burgath et al in Macromol Chem, Phys., 201 (2000) 782-791). In this case, a calibration curve is advantageously used, which was obtained in a favorable manner using polystyrene standards. These quantities therefore represent apparent measured values.
  • GPC gel permeation chromatography
  • the number average molecular weight can also be determined by steam or membrane osmosis, the z. In K.F. Arndt; G. Müller; Polymer characterization; Hanser Verlag 1996
  • the polydispersity M w / M n of preferred oligomers or polymers is preferably in the range of 1-10, favorably in the range of 1-8, in particular in the range of 1-6.
  • the viscosity of the oligomers or polymers to be used according to the invention is less than 1,000 Pas, preferably less than 800 Pas, more preferably less than 700 Pas, even more preferably less than 500 Pas, in particular less than 300 Pas, and is favorably in the range from 50 mPas to 700 Pas, especially preferably in the range of 70 mPas to 300 Pas, in particular in
  • Range from 100 mPas to 300 pas. It is preferably measured at 30 ° C. and a shear rate of 30 Hz between two 20 mm plates.
  • the degree of branching of the oligomer or polymer is suitably in the range of> 0.0% to 75.0%, preferably in the range of> 0.0% to 70.0%, in particular in the range of> 0.0% to 65.0 %. According to a particularly preferred embodiment, the degree of branching of the oligomer or polymer is greater than 10.0%, preferably greater than 20.0%, in particular greater than 25.0%.
  • the degree of branching can be determined according to Frey or Frechet. A detailed description of this
  • the oligomer or polymer preferably determined by means of DSC glass transition temperature of less than 150 0 C, preferably less than 125 ° C, especially less than 100 0 C, to.
  • the determined by means of DSC Melting temperature of the oligomer or polymer is suitably less than 300 0 C, preferably less than 250 0 C, in particular less than 200 ° C.
  • the vapor pressure of the oligomer or polymer is comparatively low and preferably less than 0.1 bar, preferably less than 0.07 bar, in particular less than 0.02 bar, in each case measured at 20 ° C.
  • the oligomer or polymer has one or more ionic structures, wherein the polymer comprises one or more groups with positive or negative partial charge, which are optionally neutralized by corresponding counterions.
  • Particularly suitable ionic structures in this context include quaternary ammonium salts, oxonium salts, sulfonium salts, imidazolium salts, and phosphonium salts, where the cation is preferably covalently bonded to the oligomer or polymer.
  • Particularly useful counterions include halides, especially chloride, bromide, hydroxide, sulfate, nitrate, acetate, methylsulfate, ethylsulfate, methylsulfonate, and carbonate.
  • the oligomer or polymer has no ionic structures.
  • inventively employable oligomers or polymers are already commercially available under the brand Boltorn ® from Perstorp AB hyperbranched polyester, as Polymin® ®, Lupasol ® and / or PEI ® from BASF AG available hyperbranched polyethyleneimines and also the brand under the Hybrane ® available from DSM BV, Netherlands hyperbranched polyester particularly favorable.
  • hyperbranched polyglycerols of the company Hyperpolymers with 800 g / mol ⁇ M w ⁇ 40,000 g / mol and polyethyleneimines with the type designation PEI-5 and PEI-25 as well as polyglycerols eg with the type designation PG-2, PG-5 and PG-6 of the company Hyperpolymers GmbH.
  • Another example of a particularly suitable hyperbranched polymer are Epomin® brand polyimines from Nippon Shokubai Co., Ltd.
  • the working pair contains at least one hyperbranched polyester which preferably contains units of the following monomers: a) preferred hydroxyl components: ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, glycerol, propylene glycol, dipropylene glycol, polypropylene glycol, bisphenol A, ditrimethylolpropane , Ditrimethylolethane,
  • Working pair at least one linear polyether, which preferably contains ethylene oxide, propylene oxide and / or butylene oxide units.
  • the proportion of polyether-forming ethylene oxide is preferably between 0 and 100% by weight, based on the linear polyether.
  • it advantageously has at least one butyl ether or allyl ether end group.
  • the working pair according to the invention may optionally contain further additives, such as.
  • corrosion and wear inhibitors in particular H 2 N (CH 2 ) 2 OH, HO (CH 2 ) 3 OH and / or (HOCH 2 CH 2 ) 2 NH.
  • another sorbent ie a substance that absorbs the refrigerant, such.
  • Water for the refrigerant ammonia or lithium bromide for the refrigerant water may be useful.
  • the proportion of the further sorbent is preferably less than 40.0 wt .-%, more preferably less than 30.0 wt .-%, in particular less than 20.0 wt .-%, each based on the total weight of the oligomer or polymer ,
  • the refrigerant contains no further sorbent.
  • composition of the work pair according to the invention can in principle be chosen freely and tailored to the needs of each individual case.
  • working couples have proven to be particularly useful, depending on their total weight, from A) 0.01 to 99.99 wt .-%, preferably 0.1 to 99.9 wt .-% and particularly preferably 0.1 to 99.5 wt .-% refrigerant
  • the production of the working pair according to the invention can be carried out in a manner known per se by mixing the components.
  • Particularly suitable application areas include ventilation or air conditioning technology, such as building technology, vehicle technology, ship technology, aerospace and container technology, cold stores or refrigerated trucks, such as reefers or refrigerated trucks, for the transport of food, gases, chemicals and / or animals as well as the process technology for air drying, preferably according to the condensation principle, for the absorption of gases, central or mobile systems for heat recovery, such as cogeneration plants or solar-powered systems, refrigerators, freezers and air conditioners.
  • ventilation or air conditioning technology such as building technology, vehicle technology, ship technology, aerospace and container technology, cold stores or refrigerated trucks, such as reefers or refrigerated trucks, for the transport of food, gases, chemicals and / or animals as well as the process technology for air drying, preferably according to the condensation principle, for the absorption of gases, central or mobile systems for heat recovery, such as cogeneration plants or solar-powered systems, refrigerators, freezers and air conditioners.
  • At least one component of the working pair undergoes a cyclic process with the supply or removal of heat or mechanical energy.
  • the oligomer or polymer advantageously acts as a sorbent for the absorption of at least one vapor or gaseous refrigerant.
  • the separation of the refrigerant and the oligomer is preferably carried out in an expeller and subsequent condensation of the refrigerant in a return cooler.
  • absorption refrigeration plant can be replaced by at least one apparatus in which a liquid-liquid phase separation takes place and the two liquid phases are withdrawn separately.
  • an absorbent-containing liquid phase having an absorbent concentration of at least 20% by weight and a refrigerant-containing liquid phase having a refrigerant concentration of at least 20% by weight are advantageously formed.
  • the present invention furthermore relates to refrigerating machines, in particular absorption heat pumps, absorption refrigerating machines, steam jet refrigerating machines or compression refrigerating machines which contain a condenser, an expansion element, a heat exchanger and / or an absorber and the working pair according to the invention.
  • the Chillers, in particular absorption heat pumps, absorption chillers, steam jet chillers or compression chillers preferably comprise a mixer-settler for liquid-liquid separation of the working material pair.
  • the improved property profile of the sorption substances and additives according to the invention can easily be checked on the basis of experimentally ascertainable absorption isotherms.
  • Absorption isotherms result from the amount of a volatile component (here the refrigerant), which at a given temperature and at pressures which are generally smaller than the pure vapor pressure of the refrigerant, in a very high-boiling or non-volatile liquid (here Absorbens) in an equilibrium state.
  • a volatile component here the refrigerant
  • a very high-boiling or non-volatile liquid here Absorbens
  • a sorbent should absorb the refrigerant after its expansion and evaporation at a low pressure.
  • An advantageous sorption substance absorbs as much refrigerant as possible at a given pressure, whereupon the volume and the masses of the circulatory streams are minimized. This leads to the fact that the system achieves a greater efficiency and of Their dimensions and the amount of absorber may be advantageous.
  • Example system I ammonia (NH 3 ) as refrigerant
  • water according to the prior art represents the currently most advantageous sorbent.
  • the limitation of the working temperature of the absorber to 0 ° C., based on the freezing point of water, can be lowered by more than 10 K by using the oligomers or polymers according to the invention.
  • Such a temperature reduction is particularly advantageous in multi-stage cryogenic plants (which can be well realized with this refrigerant due to the vapor pressure curve and the melting point of ammonia), since a lower absorber temperature via the reduction of the refrigerant vapor pressure always leads to an improved absorption behavior.
  • Example system II Water as refrigerant
  • the lithium bromide is one of the most advantageous sorption agents.
  • Lithium bromide has one
  • the inventive working fluid of water and an oligomer or Polymer are also less corrosive than aqueous solutions of lithium bromide.
  • Example System III 2, 2, 2-trifluoroethanol as a refrigerant
  • liquid organic salts are 1-butyl
  • 3-methylimidazolium tetrafluoroborate and 1-butyl-3-methylimidazolium bromide are suitable as sorbents for 2, 2, 2-trifluoroethanol. This is by K. -S. Kim et al. in
  • novel oligomers and polymers in particular the
  • Graft copolymers having a polyethylenimine core and polyether chains having a polyethylenimine core and polyamide chains, the hyperbranched polyesters and the linear polyethers, a significantly improved absorbency over the prior art.
  • BMIM Br l-butyl-3-methylimidazolium bromide
  • the glass transition temperature or the pure substance melting point of the sorbent can be lowered by an amount of from 20 K to more than 100 K using the oligomers and polymers of the invention which are superior to the absorption capacity as sorbents.
  • the sorption substance in the expeller can now be concentrated more vigorously without having to worry about crystallization of the sorption substance. Residues of refrigerant to prevent crystallization are - depending on the temperature in the sorbent - not necessary or may be much lower than in the prior art. This minimizes useless cycle flows and increases the efficiency of a cold process.
  • oligomers or preferably branched polymers having comparatively small molecular weights are to be preferred for these applications, since these generally have a higher mass-related absorption capacity.
  • the working pair is guided to the absorber (4) by means of a pump (5) in at least one heat exchanger (6a) in which it absorbs heat Q or write. Due to the absorption of heat or heat dissipation, the working solution which is liquid at point (4) and which, in addition to the sorption substance and the refrigerant, may also contain additives, is present in a liquid-liquid solution. Miscibility gap, which is characterized by an upper or lower critical solution temperature.
  • the Settier (7) in which the working solution in two liquid phases, a
  • Sorbent-rich and a refrigerant-rich phase segregated.
  • the settler may contain coalescence and sedimentation internals.
  • the refrigerant-rich phase is then passed through at least one heat exchanger (6b) and a throttle (8a).
  • the largely liquid refrigerant absorbs heat Q to and is thereby at least partially transferred in the vaporous state of aggregation.
  • a new heat transfer in a heat exchanger (6b) take place before the refrigerant-rich phase introduced into the absorber, absorbed by a sorbent and thereby the heat of absorption Q ab is discharged.
  • the absorbent-rich phase can be conveyed again through a heat exchanger (6a) before it is then expanded to absorber pressure in a throttle (8b) and fed to the absorber (4).
  • the settler (7) is a temperature of -50 0 C ⁇ T ⁇ 250 0 C, preferably from -20 0 C ⁇ T ⁇ 200 0 C and particularly preferably from -10 0 C ⁇ T ⁇ 180 ° C at a settler settler system pressure between 0.01 bar ⁇ P ⁇ 200 to choose bar, in the absorber (4) a temperature of -70 0 C ⁇ T ⁇ 200 ° C, preferably from -50 0 C ⁇ T ⁇ 150 0 C and particularly preferably from -30 0 C ⁇ T ⁇ 100 0 C at an absorber system pressure between 0.01 bar ⁇ P ⁇ 60 to choose bar and in the Heat exchangers (6a) and (6b) each have a heat transfer area of 0.1 m 2 ⁇ A ⁇ 300 m 2 , preferably from 0.2 m ⁇ A ⁇ 200 m and more preferably from 0.3 m 2 ⁇ A ⁇ 150
  • the sorption substances or additives according to the invention can also be used in at least one stage of a single-stage or multi-stage absorption refrigeration system with at least one heated expeller and subsequent refrigerant condenser - as exemplified in Vauck, WRA and Müller, HA, Basic Operations of Chemical Process Engineering, 10th edition, page 527, für 1994, ISBN 3-342-00629-3 described - are used.
  • Examples 1 to 5 illustrate the invention for working couples of water as a refrigerant and one of the oligomers or polymers A to E as a sorbent.
  • Polymer A is a hyperbranched polyesteramide (polymer of 2,5-dihydrofurandione with 1,1'-imino bis [2-propanol]) having an average molecular weight of 1200 g / mol and an average of 8 OH groups per
  • Polymer B is a 16 OH endblocked polyamidoamine dendrimer having a molecular weight of 3256 g / mol, available from Dendritech Inc. (Michigan, USA) under the product name PAMAM-OH.
  • Polymer C is a hyperbranched polyglycerol having an average molecular weight of 1400 g / mol, an average of 20 OH groups per molecule and a polydispersity of 1.5.
  • the polymer can be obtained under the name PGl from the German company Hyperpolymers GmbH.
  • Polymer D is a hyperbranched polyglycerol with an average molecular weight of 6000 g / mol, an average of 80 OH groups per molecule and a polydispersity of 2.4.
  • the polymer may be under the
  • Designation PG3 be purchased from the German company Hyperpolymers GmbH.
  • Oligomer E is a polyethylene glycol having an average molecular weight of 600 g / mol, which is available from Conlac GmbH under the name PEG 600.

Abstract

L'invention concerne une paire de travail pour des processus de refroidissement et/ou des réfrigérateurs, contenant A) au moins un réfrigérant et B) au moins un oligomère ou polymère. (i) le réfrigérant comprend 1% en poids maximum d'hydrocarbures contenant halogène, dont le point d'ébullition est situé en-dessous de 70°C mesuré comme une substance pure par 101325 Pa, le pourcentage en poids étant relatif au poids total du réfrigérant. (ii) L'oligomère et le polymère présentent un poids moléculaire moyen compris entre 300 g/mol to 50,000 g/mol, mesuré par chromatographie sur gel. (iii) L'oligomère ou le polymère présente une solubilité minimale de 1g par rapport à 100g d'agent refroidissant dans l'agent refroidissant à 50°C. Et (iv) la viscosité de la solution d'une solution d'agent de refroidissement- oligomère ou une solution agent de refroidissement- polymère contenant 10% en poids d'oligomère ou de polymère est inférieurà 700 mPas mesurés en fonction de la norme DIN 53019 à 60°C et une vitesse de cisaillement de 50 Hz.
PCT/EP2007/051508 2006-02-28 2007-02-16 Milieux de travail pour des processus de refroidissement WO2007099041A1 (fr)

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US9840473B1 (en) 2016-06-14 2017-12-12 Evonik Degussa Gmbh Method of preparing a high purity imidazolium salt
US9878285B2 (en) 2012-01-23 2018-01-30 Evonik Degussa Gmbh Method and absorption medium for absorbing CO2 from a gas mixture
US10105644B2 (en) 2016-06-14 2018-10-23 Evonik Degussa Gmbh Process and absorbent for dehumidifying moist gas mixtures
US10138209B2 (en) 2016-06-14 2018-11-27 Evonik Degussa Gmbh Process for purifying an ionic liquid
US10493400B2 (en) 2016-06-14 2019-12-03 Evonik Degussa Gmbh Process for dehumidifying moist gas mixtures
US10500540B2 (en) 2015-07-08 2019-12-10 Evonik Degussa Gmbh Method for dehumidifying humid gas mixtures using ionic liquids
US10512881B2 (en) 2016-06-14 2019-12-24 Evonik Degussa Gmbh Process for dehumidifying moist gas mixtures
US10512883B2 (en) 2016-06-14 2019-12-24 Evonik Degussa Gmbh Process for dehumidifying moist gas mixtures

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Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US9878285B2 (en) 2012-01-23 2018-01-30 Evonik Degussa Gmbh Method and absorption medium for absorbing CO2 from a gas mixture
US10500540B2 (en) 2015-07-08 2019-12-10 Evonik Degussa Gmbh Method for dehumidifying humid gas mixtures using ionic liquids
US9840473B1 (en) 2016-06-14 2017-12-12 Evonik Degussa Gmbh Method of preparing a high purity imidazolium salt
US10105644B2 (en) 2016-06-14 2018-10-23 Evonik Degussa Gmbh Process and absorbent for dehumidifying moist gas mixtures
US10138209B2 (en) 2016-06-14 2018-11-27 Evonik Degussa Gmbh Process for purifying an ionic liquid
US10493400B2 (en) 2016-06-14 2019-12-03 Evonik Degussa Gmbh Process for dehumidifying moist gas mixtures
US10512881B2 (en) 2016-06-14 2019-12-24 Evonik Degussa Gmbh Process for dehumidifying moist gas mixtures
US10512883B2 (en) 2016-06-14 2019-12-24 Evonik Degussa Gmbh Process for dehumidifying moist gas mixtures

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