A cryogenic insulation multilayer system and a method for obtaining the rigid polyurethane foam composite for the cryogenic insulation multilayer system

Abstract

Invention refers to a cryogenic insulation multilayer system comprising a base layer and a rigid foam composite layer, wherein the base layer is a metal plate, and wherein the rigid foam composite layer is made of a rigid polyurethane foam and a phase change material in an amount of 2.5 to 7.5 weight %, preferably about 5 weight %, of total mass of the rigid foam composite layer, and wherein the rigid foam composite layer is sprayed on the metal plate so that the adhesion strength is in a range of 0.2 to 0.4 MPa. Inventions is also a method for obtaining the rigid foam composite layer of the cryogenic insulation multilayer system.

Description

[0001] A CRYOGENIC INSULATION MULTILAYER SYSTEM AND A METHOD FOR OBTAINING THE RIGID POLYURETHANE FOAM COMPOSITE FOR THE CRYOGENIC INSULATION MULTILAYER SYSTEM

[0002] Technical field

[0003]

[0001] Method applies for obtaining rigid polyurethane foam composite which is intended to be used in cryogenic insulation.

[0004] Background

[0005]

[0002] Rigid polyurethane foam (PUR) is used as thermal insulation material in houses, automotive industry and in domestic appliances such as refrigerators and freezers. Due to its low density and high mechanical performance PUR can also be used as insulation in low temperatures (below - 30 °C), including in cryo-temperatures (below -120 °C). Such low temperatures are being used in storage and exploitation of liquefied gases (natural gas, nitrogen, oxygen, hydrogen, etc.). Liquefied oxygen and hydrogen are being used as effective fuel in aviation and space industry, meanwhile liquefied natural gas can be used in on-ground applications. Therefore, considering exploitation conditions, insulation of PUR has to withstand mechanical forces and high temperature difference.

[0006]

[0003] Meanwhile polyisocyanate used for PUR production is obtained from petrochemical resources, polyols can also be obtained from renewable resources, for example, plant oils. Tall oil which is obtained as by-product in pulp production, can also be used as an alternative for polyol synthesis. Therefore, using polyols from renewable resources, sustainability of PUR material increases, but at the meantime characteristics of the materials does not deteriorate.

[0007]

[0004] Phase change materials (PCM) have a high thermal energy storage which ensures minimal loss of heat. PCMs are being used in low temperature storage systems due to their ability to balance heat charging-discharging phenomena, by absorbing heat in their molecules. In combination with PUR composite with high energy efficiency and mechanical characteristics is obtained.

[0008]

[0005] Several researches about PUR-PCM composites have been studied. PUR-PCM composites have been studied in decreased temperature storage system for food storage

[0001] , as binder in asphalt blend and its characteristics in low temperatures [2], PUR composited reinforced with PCM have produced reduced cell size which decreases thermal conductivity (for silicon dioxide tanks) [3],

[0006] Method for producing and storing thermal energy has been studied [4], This material contains at least one fatty acid or fatty acids derivative, paraffin or equivalent, and also polyol or equivalent. Optionally, the coating or encapsulation of the known material-containing particles includes a coating or encapsulating material - polyurethane.

[0009] Summary of the invention

[0010]

[0007] The aim of the invention was reached by a design a cryogenic insulation multilayer system comprising a base layer and a rigid foam composite layer. The base layer is a metal plate. The rigid foam composite layer is made of a rigid polyurethane foam and a phase change material in an amount of 2.5 to 7.5 weight %, preferably about 5 weight %, of total mass of the rigid foam composite layer. The rigid foam composite layer is sprayed on the metal plate so that the adhesion strength is in a range of 0.2 to 0.4 MPa. The rigid polyurethane foam is combination of isocyanate and bio-based polyol.

[0011]

[0008] The phase change material may be selected from a group comprising paraffins, salt hydrates, fatty acids and eutectics. Preferably, the phase change material is an encapsulated phase change material Crodatherm ME 29P — PW — (MW) made by CRODA NORDIC A AB, Limhamn, Sweden.

[0012]

[0009] The invention was also a method for obtaining the rigid foam composite layer of the cryogenic insulation multilayer system. The method includes the following steps: a) obtaining of a polyurethane matrix by combining isocyanate and bio-based polyol; b) addition of a physical blowing agent to the polyurethane matrix to obtain foam structure; c) addition of a phase change material to the polyurethane matrix, which was obtained in step b), in amount of 2.5 - 7.5 weight %, preferably about 5 weight %, of total mass of the rigid foam composite; and d) curing of the composite to obtain a rigid foam composite layer.

[0013]

[0010] In accordance with one of method’s indication, bio-based polyol can be chosen epoxidized tall oil-diethanolamine polyol, epoxidized tall oil-fiethyleneglycol polyol or other epoxidized plant oil derivative (for example, castor oil-diethanolamine polyol, soy bean oil-diethanolamine polyol, sunflower oil-diethanolamine polyol, corn oil-diethanolamine polyol, linseed oil-diethanolamine polyol). In accordance with other method’s indication as bio-based polyol can be chosen mixture of epoxidized tall oil-diethanolamine polyol and epoxidized tall oil-diethylene glycol polyol in mass ratio 1.5:1.

[0014]

[0011] In accordance with other method’s indication as physical blowing agent can be chosen trans- l-chloro-3,3,3-trifluoropropene with chemical structure: or cis- 1,1, 1,4, 4, 4-hexafluoro-2-buthene with structure:

[0015] Brief description of the drawings

[0016]

[0012] Structure and characteristics of the rigid foam composite layer of the cryogenic insulation multilayer system and proposed method for obtaining rigid polyurethane foam composite for cryogenic insulation is depicted as diagrams in Fig. 1 to 6.

[0017] Fig. 1 are depicted diagrams which present the coefficient of thermal conductivity, density, closed cell content and safety coefficient of composite obtained with proposed method.

[0018] Fig. 2 is depicted diagram which presents compressive strength of composite obtained with proposed method.

[0019] Fig. 3 is depicted diagram which presents adhesion strength of composite obtained with proposed methods.

[0020] Fig. 4 are depicted diagrams which present the coefficient of thermal conductivity, density, closed cell content and safety coefficient of composite obtained with proposed method.

[0021] Fig. 5 is depicted diagram which presents compressive strength of composite obtained with proposed method.

[0022] Fig. 6 is depicted diagram which presents adhesion strength of the rigid foam composite layer. Detailed description

[0023]

[0013] 1stexample of obtaining the rigid foam composite layer:

[0024] The rigid foam composite layer (proposed name CryoPuRlO) was obtained using two bio-based polyols (epoxidized tall oil-diethanolamine polyol and epoxidized tall oil-diethylene glycol polyol at mass ratio 1.5: 1) and / ra».s- l -chloro-3,3,3-trifluoropropene with chemical structure: as physical blowing agent. PCM was added at the following concentrations - 2.5, 5, 7.5 and 10 weight % from total PUR-PCM composite mass. The addition of PCM encouraged the increase of the coefficient of thermal conductivity X and density p. Also, the increase of closed cell content and safety coefficient can be depicted by increasing the concentration of PCM in composite. From these results (presented in Fig. 1) it can be observed that 5 % of PCM is the optimum amount that can be added to PUR for composite to maintain its properties.

[0025]

[0014] Compressive properties of obtained composites were also measured. From obtained results it was concluded that addition of PCM increases compression strength at liquefied nitrogen temperature of composite at least twice comparing with compression strength at room temperature of the same composite (Fig. 2).

[0026]

[0015] After performing adhesion test it was observed that the addition of 5, 7.5 and 10 % of PCM to composite increases adhesion strength against metal surface after cryo-shock (Figure 3), which can be considered unique and important enough characteristic taking into account that material is intended as cryogenic insulation. Cryo-shock is performed by keeping material in liquefied nitrogen (-196 °C) for one hour.

[0027]

[0016] 2ndexample of obtaining the rigid foam composite layer:

[0028] Obtaining of composite CryoPuR20 was completed by using two bio-based polyols (epoxidized tall oil-diethanolamine polyol and epoxidized tall oil-diethylene glycol polyol at mass ration 1.5: 1) and cis- 1,1, 1,4, 4, 4, -hexafhioro-2-buthene with chemical structure: as physical blowing agent. PCM was added at the following concentrations - 2.5, 5, 7.5 and 10 weight % from total composite mass.

[0029]

[0017] Similarly to CryoPuRlO composite in this case also increase of the coefficient of thermal conductivity, density, closed cell content and safety coefficient.

[0030]

[0018] Even though increase of density and the coefficient of thermal conductivity is not a desirable characteristic if material is intended as cryogenic insulation, the increase was rather insignificant and does not affect overall composite’s characteristics (Fig. 4).

[0031]

[0019] Compressive properties were also performed for CryoPuR20 composites. It was observed that the difference of compression strength in Z and X direction in liquefied nitrogen temperature is less diverse than CryoPurl 0 composite (Fig. 5); this was observed in composites with 2.5 and 5 % concentration of PCM. Even though compression strength decreases with growing PCM content in composite, the decline is rather insignificant.

[0032]

[0020] Adhesion tests showed increase of adhesion strength in composites with higher PCM content (up to 5 %) in both samples with and without cryo-shock. Composites with 7.5 and 10 % concentration of PCM showed higher adhesion strength after cryo-shock (Fig. 6).

[0033]

[0021] Even though the addition of PCM to PUR does not improves all characteristics (improvement was observed for safety coefficient), it increases the amount of sustainable material in composite. Composites with PCM concentration up to 5 % show the most optimum characteristics. These characteristics indicated that composites can be used as cryogenic insulation in both domestic and industrial technologies.

[0034]

[0022] Results of research and performed experiments showed that proposed method provides higher adhesion strength to cryogenic tank metal surface after cryo-shock which is significant if PUR is being used as cryogenic insulation material. References

[0035] 1. Sarkar, S., et. al. Developments in phase change material (PCM) doped energy efficient polyurethane (PU) foam for perishable food cold-storage applications: A review, doi:

[0036] 10.1016 / j.est.2O22.104620.

[0037] 2. Wang, X., et. al. Thermal storage properties of polyurethane solid-solid phase change material with low phase-change temperature and its effects on performance of asphalt binders, doi: 10.1016 / j.est.2022.105686.

[0038] 3. Goitandia, A. M., et. al. Invigorating Polyurethane Foams With Phase Change Materials Supported in Inorganic Containers, doi: 10.1002 / pc.24082.

[0039] 4. WO 2019014215 Al.

Claims

CLAIMS1. A cryogenic insulation multilayer system comprising a base layer and a rigid foam composite layer, wherein the base layer is a metal layer, and wherein the rigid foam composite layer is made of a rigid polyurethane foam and a phase change material in an amount of 2.5 to 7.5 weight %, preferably about 5 weight %, of total mass of the rigid foam composite layer, and wherein the rigid foam composite layer is sprayed on the metal plate so that the adhesion strength is in a range of 0.2 to 0.4 MPa.

2. The cryogenic insulation multilayer system according to claim 1, wherein the rigid polyurethane foam is combination of isocyanate and bio-based polyol.

3. The cryogenic insulation multilayer system according to claim 1 or 2, wherein the phase change material is selected from a group comprising paraffins, salt hydrates, fatty acids and eutectics.

4. The cryogenic insulation multilayer system according to any of claim 1 to 3, wherein the phase change material is an encapsulated phase change material Crodatherm ME 29P — PW — (MW) made by CRODA NORDICA AB, Limhamn, Sweden.

5. A method for obtaining the rigid foam composite layer of the cryogenic insulation multilayer system according to any of claims 1 to 4, wherein the method includes the following steps: a) obtaining of a polyurethane matrix by combining isocyanate and bio-based polyol; b) addition of a physical blowing agent to the polyurethane matrix to obtain foam structure; c) addition of a phase change material to the polyurethane matrix, which was obtained in step b), in amount of 2.5 - 7.5 weight %, preferably about 5 weight %, of total mass of the rigid foam composite; and d) curing of the composite to obtain a rigid foam composite layer.

6. The method according to claim 5, wherein the bio-based polyols are mix of epoxidized tall oil-di ethanolamine polyol and epoxidized tall oil-diethyleneglycol polyol in 1.5: 1 mass ratio.

7. The method according to claim 5 or 6, wherein the physical blowing agent is trans- -chloro- 3, 3, 3 -trifluoropropene with chemical structure:or cis- 1 , 1 , 1 ,4,4,4-hexafhioro-2-buthene with chemical structure:

8. The method according to any of claims 5 to 7, wherein the phase change material is selected from a group comprising paraffins, salt hydrates, fatty acids and eutectics.

9. The method according to any of claims 5 to 8, wherein the phase change material is an encapsulated phase change material Crodatherm ME 29P — PW — (MW) made by CRODA NORDICA AB, Limhamn, Sweden.

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