JP2016166735A - Heat transfer interface - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heat transfer interface.SOLUTION: An object of an embodiment of the present invention is to provide a system and method for a thermal management system at temperatures within a range of 120-1,300°C. The present system consists of a variety of thermal transfer chambers configured to include a thermal transfer device which is in a spherical or cylindrical shape or other shapes, and absorbs heat within a wide temperature range and returns such heat of certain temperature for an extended period. The thermal management system includes a plurality of heat transfer particles, which each consist of an inside heat transfer medium charged in an outer container, the outer container being inactive to a heat source and enabling fast acquisition of heat of temperature within the range of 120-1,300°C from the heat source and subsequent dissipation of heat of certain temperature for a certain time.SELECTED DRAWING: Figure 8

Description

  The present invention relates to the field of thermal management. In particular, embodiments of the present invention relate to systems and methods for storing heat from a production process and recovering such heat at a constant temperature for an extended period of time.

  Today, many production processes generate large amounts of waste heat that is dissipated in an evaporation tower (ie, cooling tower), transferred to cooling water, converted to steam, or discarded to the surrounding environment. ing. Moreover, many industrial activities are inherently intermittent, so the heat generated in these processes is not continuous and lasts only for a limited time, and the temperature of their heat source is It fluctuates greatly, thus making heat recovery and heat recycling difficult and cumbersome. As a result, large amounts of energy are routinely discarded or simply dissipated in cooling water streams, which are low grade steam, thus making such production processes more energy intensive than necessary.

  Furthermore, many exothermic polymer reactions in the petrochemical industry generally require precise temperature control that is achieved using a double wall reactor with cooling water. However, even when such a reactor utilizes a large amount of cooling water and turbulence in the outer shell, temperature control is generated through the entire volume of the inner reactor and away from the cooling wall. Therefore, it is difficult. In addition, these cooling systems generate large amounts of cooling water at temperatures that are too low for effective heat recovery. As a result, these petrochemical processes incur a substantial cost to the water treatment facility before discarding a significant amount of heat and water and discharging such waste.

  Molten salt systems have been developed to store heat at high temperatures and are primarily used in conjunction with solar concentrators. Such systems typically rely on heat of fusion, much greater than the specific heat per unit mass, and can release that heat continuously upon solidification or freezing. Sodium metal is also used for heat storage at higher temperatures, but in the case of sodium, heat storage occurs primarily by heating liquid sodium to higher temperatures. Conventional molten salt systems and molten sodium systems suffer from two major problems. That is, what to do when the system fails and salt or sodium freezes, and the need to pump the semi-viscous medium at high temperatures.

  Therefore, heat can be absorbed at high temperatures, such heat can be delivered at a constant temperature over a long period of time, requires little or no maintenance, is reliable, and the heat transfer medium is frozen. However, there is a need for an inexpensive heat transfer medium that can be easily operated.

  There are a number of techniques related to energy or heat management or storage using molten salts. However, many of these techniques have little relevance to the present invention because they involve different functionalities. Thus, many are associated with ion exchange resins, some with polymer systems, some with thermoplastics, all known to be susceptible to thermal degradation at relatively medium temperatures. , With organic polymers, and others, with respect to geothermal heat treatment of hydrocarbon deposits and materials, which are rarely encapsulated, or to phase change inks, toner compositions, and imaging systems. Some technologies relate to pharmaceutical or biological systems, while others relate to flame retardants or fire retardants, but they are all little related to thermal management or storage systems that use phase change salts.

  Many technologies employ phase change materials, which are primarily salts, and many employ eutectic compositions of various salts, but they are rarely encapsulated and thus solidify. Share freezing issues according to

  Some technologies employ heat pipes associated with energy storage systems based on phase change materials and connected to such heat storage systems, including heat exchangers. Others employ phase change materials that are compacted into powder form and encapsulated by a rolling process. However, the usual problems encountered with the use of heat exchangers using molten salts are exacerbated and the encapsulation method employed involves expensive manufacturing and is limited to simple shapes.

  Other techniques employ hydrated metal nitrates that minimize density changes between the solid and liquid phases. However, hydrated salts readily lose water of hydration in response to heating, and such chemical changes typically occur when or before the melting point of these materials is reached. As a result, any free water can evaporate, leading to pressure buildup in any enclosure. Thus, an important feature of these technologies is that they are suitable for use in the aforementioned applications.

  Some techniques involve the use of crystallization inhibitors to lower the temperature of solidification of the phase change material, while others employ similar systems that use a separate crystal nucleation agent.

  Other techniques relate to methods of storing heat within a wide temperature range by using various phase change salt materials and porous support structures. However, a common difficulty in all such phase change systems is the lack of fluidity, ie the fact that the flow stops as the phase change material freezes.

  Still other techniques employ anhydrous sodium sulfate and similar phase change salts in conjunction with heat exchangers that are configured to provide uniform heat distribution throughout the phase change material. However, a common deficiency of such systems is the same as before, i.e. the fact that in response to freezing, such materials completely lose their fluidity.

  Other methods employ a heat pipe and a mechanism for scraping the eutectic mixture of salt from the pipe, while the molten salt provides heat to boil the water. However, eutectic compositions pose the problem that such salt mixtures tend to be more soluble in materials encapsulating phase change salts.

Embodiments of the present invention provide fast capture heat of heat at temperatures in the range of 120 ° C. to 1,300 ° C. from various heat sources and subsequent release of such heat at a constant temperature over time. And provide an improved method for thermal management. The system can be cylindrical, spherical, or other shape, and can include an inner heat transfer medium enclosed in an outer container that is inert to the heat source. The heat transfer medium can include a salt, metal, or ceramic composition and can remove heat by absorbing heat of fusion from a heat source. The enclosure may include a metal, plastic, or ceramic composition that is non-reactive to a heat source and non-reactive to a heat transfer medium. In system embodiments, the size and shape of the enclosure is determined by the nature and chemical characteristics of the heat source and by heat transfer requirements in terms of heat removal or release per unit volume and per unit time.
For example, the present invention provides the following items.
(Item 1)
A heat management system including a plurality of heat transfer particles, each of the plurality of heat transfer particles comprising an inner heat transfer medium enclosed in an outer container, the outer container being inert to a heat source. A system that allows fast capture of heat at a temperature in the range of 120 ° C. to 1,300 ° C. from a heat source and subsequent release of heat at a constant temperature over a period of time.
(Item 2)
Item 1. The heat transfer medium includes a material selected from the group consisting of a salt, a metal, and a ceramic composition, and is capable of removing heat from the environment by absorbing heat of fusion from the heat source. System.
(Item 3)
The container includes a material selected from the group consisting of a metal, plastic, or ceramic composition that is non-reactive to the heat source and non-reactive to the heat transfer medium. The system according to 1.
(Item 4)
Item 3. The system of item 2, wherein the heat transfer medium has a melting temperature in the range of 120C to 1,300C.
(Item 5)
The heat transfer medium is chloride, acid chloride, fluoride, sulfate, sulfite, carbonate, bicarbonate, borate, arsenate, aluminate, bromide, chromate, hydride, Item 3. comprising a material selected from the group consisting of manganate, silicate, sulfide, titanate, telluride, selenide, oxide, hydroxide, metal, and mixtures thereof. System.
(Item 6)
Item 3. The system of item 2, wherein the heat transfer medium comprises a material having a boiling point or decomposition temperature that is at least 100 ° C above its melting temperature.
(Item 7)
Item 3. The system of item 2, wherein the heat transfer medium comprises a material having a very low vapor pressure at its melting temperature.
(Item 8)
Item 3. The system of item 2, wherein the heat transfer medium includes two or more substances that chemically react at a given temperature and thereby absorb the heat of reaction.
(Item 9)
9. The system of item 8, wherein the heat transfer medium decomposes at a given temperature, thereby releasing reaction heat to the environment.
(Item 10)
The container consists of copper, aluminum, chromium, iron, lead, magnesium, nickel, metal alloys, high temperature plastics such as fluorocarbons or chlorofluorocarbons, and ceramics such as silicates, alumina, and similar poorly soluble compositions. 4. The system of item 3, comprising a material selected from the group.
(Item 11)
4. The system of item 3, wherein an inner surface of the container is coated with a material that is non-reactive with the heat transfer medium.
(Item 12)
4. The system of item 3, wherein the outer surface of the container is coated with a material that is non-reactive with the heat source.
(Item 13)
10. The container coating of item 9, wherein the container coating comprises a material selected from the group consisting of carbides, oxides, silicates, polymers, metals, or similar non-reactive compositions to the heat transfer medium. System.
(Item 14)
11. The system of item 10, wherein the container coating comprises a material selected from the group consisting of carbides, oxides, silicates, polymers, metals, or similar non-reactive compositions to the heat source. .
(Item 15)
The thermal management system of claim 1, wherein the heat transfer particles comprise a plurality of phase change materials suitable for a range of temperatures such that the system recovers heat from the particles at various constant temperatures. .
(Item 16)
14. The system of item 13, wherein the heat source comprises waste heat from a chemical reactor that processes an exothermic reaction.
(Item 17)
14. A system according to item 13, wherein the heat source includes waste heat from a steelmaking furnace.
(Item 18)
14. The system of item 13, wherein the heat source comprises waste heat from an industrial boiler.

1a and 1b are elevational views of two embodiments of an encapsulated heat transfer device. Figures 2a and 2b are embodiments of a heat transfer device with an inner coating. Figures 3a and 3B are elevational views of a heat transfer device with inner and outer coatings. Figures 4a and 4b show two possible heat transfer device embodiments inside different heat transfer reactor configurations. FIG. 5a is a schematic view of a double wall petrochemical reactor chamber. FIG. 5b is a simplified petrochemical reactor with a heat transfer device that is randomly distributed. FIG. 6 is a schematic diagram of a steel basic oxygen converter with a heat recovery chamber. FIG. 7 is a schematic diagram of a reciprocating boiler system with a heat recovery chamber. 8a and 8b are elevation and plan views of a coaxial heat recovery dual chamber with a heat transfer device.

  Embodiments of the invention are disclosed herein, in certain cases, in an exemplary form, or by reference to one or more figures. However, any such disclosure of specific embodiments is exemplary only and does not represent the full scope of the invention.

  Embodiments of the present invention include systems, methods, and apparatus for thermal management, recovery, and recycling from various production processes. The preferred embodiment operates within a temperature range of 120 ° C to 1,300 ° C and is fully automatic at temperatures similar to that range for hours, days, or months without user intervention. An extensive heat absorption chamber is provided that provides heat recovery. For example, the system disclosed herein can operate without user control or intervention for 2, 4, 6, 8 or more months. In a preferred embodiment, the system can operate automatically for 1, 2, 3, 4, 5, 6, 7, 8 years or more.

  Embodiments of the present invention provide encapsulated heat transfer devices of various shapes and sizes for entering and exiting a heat transfer chamber at a rate proportional to the amount of waste heat available and its temperature. Thus, encapsulating a heat transfer device within a rigid, impermeable enclosure would result in such a mechanical system, regardless of the state of the encapsulated material, typically a salt or a mixture of salts. Allows flow driven by gravity and thus provides fluidity. When heat is available, it is first encapsulated that heats until the melting point is reached, and then continues to absorb the heat of fusion until all of the encapsulated material is in a molten state It is easily absorbed by the phase change material. When heat is needed, the encapsulated material is transferred to another heat transfer chamber and the melt phase change material begins to solidify, thus releasing the same heat of fusion previously absorbed.

  The heat transfer chamber can be of any shape and size that can accommodate the amount of heat available, the length of time such heat is available, and the temperature. Those three variables are used so that they have a residence time in the transfer chamber equal to that of the available heat and that the mass of the phase change material is appropriate for the amount of heat and temperature available. Determine the size and shape of the heat transfer device.

  An important property of the heat transfer chamber is to allow movement of the heat transfer device from inside and outside such chamber, such as by gravity flow, but other forms of mechanical transport may be employed.

  An important characteristic of heat transfer devices is that they are durable, can be processed inexpensively, and are thermally effective. Durability requires that there be no chemical interaction between the encapsulant material of the device and the inner phase change material. Inexpensive manufacture requires that the encapsulated phase change material be encapsulated in an impermeable container that is easy to process, such as a crimped metal cylinder, metal or ceramic sphere. Thermal effectiveness requires that the encapsulant material thickness be small and thermally conductive and not chemically react to either the external environment providing heat or the internal environment of the phase change material. And

  In preferred embodiments, such as those shown in FIGS. 1A and 1B, the heat transfer device (1) comprises an encapsulant (2) filled with a phase change material (3), which can be an inorganic salt or a mixture of salts. It comprises a cylinder or sphere, or a similar shape. The cylinder or sphere is made from a metal such as copper or aluminum, or a similar inexpensive metal. In other embodiments, the encapsulating material (2) may be a thin ceramic or polymeric material that is made thermally conductive by incorporating metal powder or sawdust. In a preferred embodiment, the encapsulating material (2) consists of a crimped aluminum, copper, or similar metal tube, a welded tube, or a tube or similar shape that is fitted with a screw cap.

  2a and 2b show a heat transfer device (in which the inner surface of the encapsulating material is coated with an inert material (21) that is chemically non-reactive with the encapsulating material (2) or the phase change material (3)). 1 illustrates an alternative embodiment of 1). As used herein, “non-reactive” means a material for a heat transfer device that reacts chemically with a material that is completely non-reactive, but the reaction is very slow or slight. Or both materials that do not appreciably affect the chemical properties of the structure. Suitable coatings include electrodeposited metals and alloys, paints, ceramic compositions, or polymers. Examples of inexpensive coatings on copper, aluminum, and similar materials include carbides, nitrides and oxides. Examples of coating methods include chemical vapor deposition, electrostatic vapor deposition, anodizing, electrolysis, and coating. Useful information regarding corrosion and coating is provided in Handbook of Corrosion Engineering and is hereby incorporated by reference in its entirety.

  Figures 3a and 3b show that both the inner and outer surfaces of the encapsulant (2) are chemically non-existent with either the encapsulant (2), the phase change material (3) or the external environment in which the heat transfer device operates. 3 illustrates an alternative embodiment of a heat transfer device (1) that is coated with inert materials (21) and (31) that are reactive. Suitable coatings include electrodeposited metals and alloys, paints, ceramic compositions, or polymers. Examples of inexpensive coatings on copper, aluminum, and similar materials include carbides, nitrides and oxides. Examples of coating methods include chemical vapor deposition, electrostatic vapor deposition, anodizing, electrolysis, and coating.

  FIG. 4a consists of a cylindrical configuration containing a plurality of heat transfer devices (1) arranged randomly so as to provide a sufficient porosity for the flow of a fluid medium containing heat. Illustrates one possible embodiment of the heat transfer chamber (4). FIG. 4b consists of a rectangular configuration containing a plurality of heat transfer devices (1) arranged randomly to provide sufficient porosity for the flow of a fluid medium containing heat. 4 illustrates another embodiment of a heat transfer chamber (4). Other geometries used to contain the heat transfer device are also possible. Those skilled in the art will recognize that a cylindrical or rectangular shape is merely exemplary and that other shapes may be utilized in different industrial applications to meet the space limitations imposed by the type of heat source. I will.

  FIG. 5a is a simplified schematic diagram of a double wall petrochemical reactor typical of a catalytic process with an exothermic reaction. In FIG. 5a, the reactor (6) has cooling water flowing through port (62) and port (63) to provide cooling for the heat generated in the reactor volume (61). ) Through two concentric cylindrical tanks. Such reactors are widely used in the chemical industry to control reaction temperatures and are known to require large amounts of cooling water and pumps. FIG. 5b illustrates a simplified reactor configuration consisting of a reactor (6) with a single tank and multiple heat transfer devices (1) that provides more efficient cooling of the exothermic reaction.

FIG. 6 illustrates heat recovery from a basic oxygen converter (7) in a steel plant. Typically, these converters are lined with special sparingly soluble materials (71) and initially serve to cool the molten iron (72) from the blast furnace, some solvents, and the molten iron, Filled with some steel scrap (73). When the converter is full, an oxygen lance (74) blows oxygen into the molten iron to oxidize excess amounts of carbon in the molten iron and produce steel. The reaction of oxygen and carbon dissolved in the molten iron is a super-exothermic reaction that raises the temperature of the melt-fill and produces a large amount of ultra-high temperature gas, usually above 1500 ° C. Hot gas, consisting mostly of CO ₂ , exits from the top of the converter and is collected in the hood (75). The hot gas is largely due to the heat transfer device (1) flowing inside the heat transfer chamber (5) so that the residence time inside the chamber precisely balances the amount of heat produced by the hot gas. It carries a large amount of heat that is captured.

  FIG. 7 illustrates heat recovery from an industrial boiler (8). Typically, the burner (81) provides the necessary heat by burning fuel in the firebox. The hot combustion gas initially transfers heat to the plurality of high pressure steam tubes (82), followed by the plurality of water boiling tubes (83), and the preheating chamber (84), and exits the chimney (85). A heat transfer chamber (5), connected to the chimney (85), moves through the chamber (5) at a rate proportional to the residence time required to capture the heat contained in the flue gas. The heat contained in the high-temperature combustion exhaust gas is recovered by transferring heat to the plurality of heat transfer devices (1).

  Figures 8a and 8b illustrate elevation and plan views of the system (9) for recovering useful heat from the heat transfer device (1). In FIG. 8a, the two concentric chambers (91) and (92) have a lower temperature heat transfer so that the high temperature heat transfer device (11) at ultra high temperature extends the time of heat recovery at the lower temperature. Allows heat to be transferred to the device (12). Thus, although at a very high temperature, but for a limited time, the trapped heat is available on a continuous basis at a lower temperature. As will be appreciated by those skilled in the art, different configurations can be used to transfer heat from high temperature to low temperature, and other shapes other than cylindrical or rectangular chambers may be used.

  The heat transfer device can be made from any suitable material. Exemplary materials for encapsulating the phase change medium include, but are not limited to, metals, glass, composites, ceramics, plastics, stones, cellulosic materials, fiber materials, and the like. If desired, a mixture of materials can be used. One skilled in the art will be able to determine suitable materials for each specific purpose. The selected material is preferably capable of withstanding high temperature use for extended periods of time without significant rupture, destruction, other damage, or leaching of toxic materials into the environment. If desired, different sized devices can be made from different materials. For example, an enclosure for a high temperature heat transfer device can be made from a metal such as steel, titanium, or various alloys, and the phase change medium can be composed of a salt having a high melting point. The selected material may preferably be resistant to fracture, rust, or burst by a heating process. Table 1 lists several metals, along with their melting points and their heats of fusion, to facilitate the selection of suitable inclusion body materials.

Table 2 lists several salts and provides melting points arranged in ascending order as well as corresponding heats of fusion. The information in Table 2 serves to select suitable phase change media for different industrial applications and heat recovery at various temperatures.

In addition to phase change materials, chemical reactions involving reduction / oxidation (redox) can also provide heat storage and controlled heat release and can therefore be used as a medium for heat transfer applications. . For example, carbonate / bicarbonate reactions typically involve chemical changes that can be reversed in response to minute changes in temperature. Thus, ammonium bicarbonate decomposes into ammonium carbonate when the temperature changes several degrees, and the heat of reaction is absorbed or released, thereby providing functionality similar to that of phase change materials. .

  As used herein, redox reactions include those in which one or more electrons are exchanged and thus encompass a wider group of chemical reactions than those that simply involve oxygen as an oxidant.

  Typically, the chemical reaction of interest in the present application includes one in which the reactant is an organic material. Such chemical reactions are characterized by the heat of reaction, which depends greatly on the temperature of the system.

  Those skilled in the art will appreciate that these methods and devices are and can be adapted to achieve the goals and obtain the aforementioned objectives and advantages as well as various other advantages and effects. The methods, procedures, and devices described herein are presently representative of preferred embodiments, are exemplary, and are not intended as limitations on the scope of the invention. Modifications and other uses of the present specification will occur to those skilled in the art that are encompassed within the spirit of the invention and are defined by the scope of the disclosure.

  The invention described herein by way of example is preferably practiced without any element or elements, limitations or restrictions, not specifically disclosed herein. it can. The terms and expressions employed are used for purposes of explanation, not limitation, and the use of such terms and expressions is not intended to indicate an equivalent or illustrated exclusion of features illustrated and described. It should be recognized that various modifications are possible within the scope of the disclosed invention. Thus, although the present invention has been specifically disclosed by means of preferred embodiments and optional features, modifications and variations of the concepts disclosed herein may be reclassified by those of ordinary skill in the art. It should be understood that all such modifications and variations are considered within the scope of the invention as defined by this disclosure.

Claims (1)

Invention described in the specification.