Classifications

• • 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
  • C09K5/06—Materials undergoing a change of physical state when used the change of state being from liquid to solid or vice versa
  • C09K5/063—Materials absorbing or liberating heat during crystallisation; Heat storage materials
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J13/00—Colloid chemistry, e.g. the production of colloidal materials or their solutions, not otherwise provided for; Making microcapsules or microballoons
  • B01J13/0052—Preparation of gels
  • B01J13/0065—Preparation of gels containing an organic phase
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
  • C08J3/00—Processes of treating or compounding macromolecular substances
  • C08J3/02—Making solutions, dispersions, lattices or gels by other methods than by solution, emulsion or suspension polymerisation techniques
  • C08J3/09—Making solutions, dispersions, lattices or gels by other methods than by solution, emulsion or suspension polymerisation techniques in organic liquids
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16L—PIPES; JOINTS OR FITTINGS FOR PIPES; SUPPORTS FOR PIPES, CABLES OR PROTECTIVE TUBING; MEANS FOR THERMAL INSULATION IN GENERAL
  • F16L59/00—Thermal insulation in general
  • F16L59/14—Arrangements for the insulation of pipes or pipe systems

Definitions

• the present invention relates to a process for manufacturing a material based on phase change materials (PCM), quasi-incompressible and having a low thermal conductivity, as well as the product obtained by the process and applications.
• the material has the characteristic of being able to be fluidized under shear, then to gel at rest.
• the material according to the invention can be used as thermal insulator in many fields, in particular for the thermal insulation of conduits or pipes where fluids which are susceptible to significant changes of state under the influence of temperature circulate: crystallization of paraffins, deposits hydrates, ice creams, etc.
• the thermal insulation can be carried out by various methods. On land or in low immersion, porous cellular or woolly solid materials are used blocking the convection of gases with low thermal conductivity. The compressibility of these porous materials prohibits the use of this technique at a relatively high depth.
• Another known technique consists in wrapping the pipe with a first layer of a porous material soaked in paraffin for example, the coefficient of thermal insulation of which is lower than those obtained with the gas trapping technique mentioned above, and a second layer of refractory material enhancing the effect of the first layer.
• a solution cannot be used in water.
• syntactic materials consisting of hollow balls containing a gas and resistant to external pressure, embedded in binders such as concrete, epoxy resin, etc., whose conductivity is lower than that of compact materials but which are significantly more expensive.
• an external pipe resistant to hydrostatic pressure.
• Phase change materials behave like heat accumulators. They restore this energy during their solidification (crystallization) or absorb this energy during their fusion and this, in a reversible manner. These materials can therefore make it possible to increase the duration of production stoppages without risking clogging of the pipes by premature cooling of their contents.
• phase change materials mention may be made of chemical compounds of the family of alkanes C n H 2n + 2] such as for example n-paraffins (C 12 to C 60 ), which exhibit a good compromise thermal and thermodynamic properties (melting temperature, latent heat of fusion, thermal conductivity, heat capacity) and cost. These compounds are thermally stable in the range of envisaged use temperatures and they are compatible with use in a marine environment because of their insolubility in water and their very low level of toxicity, they are therefore for example well suited to thermal insulation of deep sea pipes.
• phase change materials The temperature of change of state of these phase change materials is linked to the number of carbon in the hydrocarbon chain and is therefore adaptable to a particular application.
• a phase change around 30 ° C. it is possible for example to use a mixture of paraffins predominantly in 8 such as Linpar 18-20 sold by the company CONDEA Augusta S. p. AT..
• phase change materials are in the liquid phase and their viscosity is low.
• a thickening agent such as silica to solidify them and prevent leaks.
• Phase change materials also have the disadvantage that their liquid state promotes thermal losses by convection.
• the method according to the invention makes it possible to manufacture a material or product based on quasi-incompressible phase change materials (PCM) having a low thermal conductivity at a temperature above their melting temperature Tf and fluidized under shear.
• PCM quasi-incompressible phase change materials
• It comprises the combination, with a phase change material, of a texturing agent chosen to very greatly reduce thermal convection at a temperature higher than the melting temperature of the phase change material.
• the texturing agent is dissolved in the PCM in question so as to give the phase change material a gel consistency once the material is at rest.
• the texturing agent is chosen so that it has the function of fluidification under shear. Thus, the flow of material in a tank, or a pipe can be done more easily, in particular by pumping or pouring. Once in place, the texturing agent gels the material in the place where its primary function as thermal insulator is sought.
• the product may optionally include antioxidants or antibacterial agents, corrosion inhibitors or an insoluble filler intended to adjust its density or thermal conductivity, additives intended to improve its stability or a solvent intended to control viscosity.
• the product according to the invention finds applications for thermal insulation in general. It can be applied in particular for the thermal insulation of hydrocarbon transport pipes, where it is used as a direct or interposed (injected) coating between the pipes and an external protective envelope.
• thermal insulation in general. It can be applied in particular for the thermal insulation of hydrocarbon transport pipes, where it is used as a direct or interposed (injected) coating between the pipes and an external protective envelope.
• the manufacturing process as we have seen, consists in dissolving, in a phase change material (hereinafter PCM), a texturing agent chosen to increase the viscosity of the PCM and decrease the thermal convection of the PCM to 1 liquid state, so as to form an insulating substance with blocked convection having a gelled consistency at rest, and fluidized under shear.
• PCM phase change material
• the liquid component constituting the continuous phase, can be a mixture of chemical compounds of the family of alkanes C n H 2n + 2 such as for example paraffins (C 12 to C 6 o) or waxes, normal paraffins, very weakly branched long chain isoparaffins (C 0 - C 0 (1 or 2 branches), branched long chain alkylcycloalkanes or branched long chain alkylaromatics, fatty alcohols or fatty acids.
• the liquid component represents from 60% to 99.99% of the mass of the product, the complement being the texturing agent.
• the texturing agent is:
• high-mass polymer molecular weight by weight of the order of 25,000 to 2 million g / mole: hydrocarbon polymers, polymers of esters or ethers or mixed polymers;
• the ionomer polymers are macromolecules with a molecular mass of between 1000 and 5 million, preferably between 20,000 and 1 million g / mole, which contain a small percentage of ionic groups (between 0.005% and 10% by mole, preferably between 0.01 % and 5% and more preferably between 0.2% and 3%) chemically bonded and distributed along the nonionic polymer chains. These polymers are obtained:
• a monomer functionalized with a hydrophobic monomer such as an olefin. (for example: acrylic or methacrylic acid with ethylene).
• Block copolymers are thermoplastic elastomers in which the polymer chains have a di-block, tri-block, or multi-block configuration.
• the tri-block copolymers have polystyrene (S) segments at the ends of the molecule (preferably close to 30% by mass) and an elastomer segment in its center.
• S polystyrene
• the di-block molecule simply has a polystyrene segment attached to an elastomer segment.
• the configuration and the molecular mass vary with the grade of the copolymer (the molecular mass of the polystyrene will preferably be between 5000 and 30,000 g / mol and that of the elastomer will be approximately 5000 g / mol).
• the strong interactions between the high-mass polymer and the PCM allow penetration of the PCM molecules into the polymer macromolecules. These having very large dimensions in solution, they intermingle by slowing the flow of the PCM layers to which they belong, which produces an increase in the viscosity of the composition.
• the ionic groups distributed along the chains form, by association of pairs of intermolecular ions, aggregates rich in ions.
• the aggregates formed have the consequence of increasing, in a semi-diluted regime, the viscosity of the solution compared to the same uncharged polymer of equivalent molar mass.
• the block copolymer is dissolved in the PCM by softening the polystyrene segments under the effect of temperature. The molecules are then free to move when a shear is applied. Polystyrene and elastomeric blocks are thermodynamically incompatible. Thus, the polystyrene segments at the end of the chain combine to form polystyrene domains. The elastomeric segments form separate domains. Above a critical copolymer concentration, tri-block rubbers form PCM gels with elastic behavior (cohesive gels), while di-block rubbers tend to form "greases".
• PCM-CB blocked convection phase change material
• the rate of charged groups eg for anionic: carboxylate, sulfonate, phenate, salicylate, phosphonate
• type of counterion eg for anionic: cations: amine, metal, monovalent, multivalent, ...
• compositions The PCMs with blocked convection can be formed by dissolution: la) of hydrocarbon polymers (apolar) such as polyisobutylenes or polyisobutenes (PIB); polymers of ethylene, propylene or higher carbons; copolymers of ethylene, propylene or higher carbons and their derivatives; linear, tri-block (e.g. styrene-etylene-butadiene-styrene) copolymers based on conjugated dienes (hydrogenated polybutadiene, copolymers of hydrogenated butadiene-hydrogenated styrene, hydrogenated ethylene-butadiene and hydrogenated isoprene-styrene) from home
• hydrocarbon polymers apolar
• PIB polyisobutenes
• ester polymers such as polyalkyl acrylates; polymethyl alkyl methacrylates; maleates and fumarates; itaconates; le) of mixed ester-hydrocarbon polymers such as olefin copolymers combined with esters (OCP-esters); alkyl acrylate or methacrylate - styrene polymers; alkyl acrylate or methacrylate copolymers - ⁇ olefins or polyolefins.
• ester polymers polar
• OCP-esters mixed ester-hydrocarbon polymers
• alkyl acrylate or methacrylate - styrene polymers alkyl acrylate or methacrylate copolymers - ⁇ olefins or polyolefins.
• polymers can be used alone or as a mixture (mixture of polyisobutene and hydrogenated diene-styrene, olefin polymers or copolymers, hydrogenated dienes-styrene with ester polymers or copolymers, etc.) and can be functionalized with polar patterns such as imides, succimides, vinylpyrolidone, etc.
• the blocked convection PCMs can also be formed by dissolving ionomeric polymers such as (generally the ionic polymer is neutralized by a metallic or arganometallic counterion):
• the ionic groups can be anionic (carboxylate, sulfonate, phosphonate, thioglyconate group), cationic (ammonium or pyridium salts, alkaline (Na, K) or alkaline-ferrous (Mg, Ca, Ba)), or amphoteric, or zwitterioniques (example: carboxylbétaine).
• the main known industrial ionomers are those comprising carboxylate or sulfonate groups.
• the following list is not exhaustive: - Carboxylated Ionomers: Copolymer of ethylene and methacrylic acid;
• Carboxylated elastomers polymers composed of monomers containing a carboxylic acid (generally acrylic or methacrylic acid) and monomers used to form elastomers. These are, for example, polymers of styrene-butadiene-acrylic acid, butadiene-acrylonitrile-acrylic acid, butadiene-acrylic acid, etc.; Perfluorocarboxylated Ionomers; - Sulfonated Ionomers:
• sulphonated EPDM ethylene-propylene-diene terpolymers
• a preferred diene is 5-ethylidene-2-norbornene (ENB);
• - Sulfonated elastomers polymers composed of sulfonated monomers
• the sulfonated elastomers are derived from the elastomeric polymers chosen from the group consisting of copolymers of isoprene and sulfonated styrene, copolymers of chloroprene and sulfonated styrene, copolymers of isoprene and butadiene, copolymers of styrene and sulfonated styrene, butadiene and sulfonated styrene copolymers, butadiene and styrene copolymers, isoprene, styrene and sulfonated styrene terpolymers, butadiene, styrene and sulfonated styrene terpolymers, butyl rubber, partially hydrogen
• the ionomeric polymer can be added to the PCM at concentrations varying between 0.01 to 10%, and preferably from 0.1 to 3% by mass relative to the total mass.
• Antioxidant additives can be added either during processing if the temperature is high (eg Irganox 1010 from Ciba), or when the product (PCM with blocked convection) is subjected to a temperature rise in service.
• the most frequently encountered are phenolic derivatives (dibutylparacresol, etc.), phenolic derivatives containing sulfur and aromatic amines (phenyl ⁇ or ⁇ naphthylamine or alkylated amino diphenyls).
• c) corrosion inhibitors cl) soluble in liquid PCM, consist of chemical compounds of a polar nature which are easily adsorbed on the metal surface forming a hydrophobic film (amines or fatty amides and derivatives, alkali sulfonates- earthy, etc.); c2) soluble in water and acting by passivation of the water phase (sodium nitrite for example).
• Insoluble fillers such as hollow glass microbeads, fly ash, macrobeads, hollow fibers, clay compounds, etc., will advantageously be added to the PCM-CB to adjust its density and / or its thermal conductivity.
• hydrocarbons of petroleum origin such as hydrocarbon solvents, distillation cups, predominantly aromatic, naphthenic or paraffmic oils obtained by solvent extraction processes or by processes of deep hydrotreating, solvents or sections obtained by the hydroisomerization process of paraffinic extracts of petroleum origin or of synthesis of Fischer Tropsch type, solvents and compounds obtained by synthesis, such as for example oxygenated compounds of ester type, synthetic hydrocarbons such as hydrogenated polyolefins, etc.
• a PCM co-solvent can also be used to control and adjust the influence of temperature on viscosity.
• PCM blocked convection material typically consists of 60 to 99.99% liquid PCM and a texturing agent in addition. Additives ( ⁇ 10%), fillers (5 to 60%) and solvents (0.2 to 20%) may be added.
• PCM materials with blocked convection which have been described can be used for example for the thermal insulation of subsea pipes.
• the device comprises an outer coating composed of an almost incompressible liquid / solid phase change (PCM) material having an intermediate melting temperature between the temperature of the effluents flowing in the pipe (s) and the temperature of the outside medium, and an absorbent matrix surrounding as close as possible to the pipe (s).
• PCM liquid / solid phase change
• the external coating made up of the matrix impregnated with PCM described in the previous document can here be advantageously replaced by one of the PCMs with blocked convection which have just been described, with as a result an improvement in the thermal insulation of the pipes. and a simplification of the positioning operations around the pipe or pipes, for example by pumping at a temperature above the melting temperature Tf, very appreciable when the assembly of pipes to be isolated is complex. Pumping is facilitated in that under shear, the viscosity of the material decreases.

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• 2002
  • 2002-02-04 EP EP02701389A patent/EP1360259A1/de not_active Withdrawn
  • 2002-02-04 MX MXPA03007041A patent/MXPA03007041A/es unknown
  • 2002-02-04 WO PCT/FR2002/000405 patent/WO2002062918A1/fr not_active Application Discontinuation
  • 2002-02-04 BR BR0207031-6A patent/BR0207031A/pt not_active IP Right Cessation
  • 2002-02-04 OA OA1200300196A patent/OA13297A/fr unknown
  • 2002-02-04 CN CNA028046595A patent/CN1491270A/zh active Pending
  • 2002-02-04 US US10/466,930 patent/US7320770B2/en not_active Expired - Fee Related

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