Abstract:
A heating system and method for heating fluids are provided. The heating system includes an enclosure with an inlet and outlet for fluid flow, an induction coil, thermal transmitters placed in the enclosure, and a power source for the induction coil. In one preferred embodiment, the fuel processing system includes a heating system that is at least partially filled with thermal transmitters which receive electromagnetic energy and generate heat within the heating system.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS  
       [0001]     This application claims the benefit of prior U.S. provisional application Ser. No. 60/779247 filed on Mar. 2, 2006 which is hereby incorporated by reference in its entirety. 
     
    
     BACKGROUND  
       [0002]     The present invention relates to a method and apparatus for heating fluids, particularly to a method and apparatus for heating fluids by way of induction heating.  
         [0003]     Various types of fluid heating systems are employed in the domestic, commercial, and industrial heating of fluids. There are batch heated systems (i.e. Fluid-tank heaters) and there are continuous heated systems (i.e. tankless fluid heaters). Both of these heating systems may be electrically heated and/or they may be gas-fired heated. However, these fluid heating systems can be inefficient, costly, and may not produce an effective residence time when heating the fluid.  
         [0004]     Information relevant to attempts to address these problems can be found in U.S. Pat. Nos. 6,175,689; 6,240,250; and 6,574,426. However, each one of these suffers from the fact that they all utilize electrical resistance as the heating means. Electrical resistance heating may be inefficient, costly, and may have a longer residence time compared to induction heating.  
         [0005]     In view of the foregoing, it is apparent that a need still exists for an improved process for heating fluids.  
       SUMMARY  
       [0006]     The present invention is directed to a system and method for heating fluids in which induction heating is employed in an efficient manner to heat a fluid. The heating of fluids by way of induction heating can result in the effective and rapid heating of fluids which can be very advantageous for many fluid heating applications. The induction fluid heating system comprises:  
         [0007]     (a) an enclosure having an inlet for receiving fluid and an outlet for fluid to exit said enclosure;  
         [0008]     (b) at least one induction coil at least partially surrounding said enclosure;  
         [0009]     (c) at least one thermal transmitter placed within said enclosure wherein said at least one thermal transmitter receives electromagnetic energy from said at least one least one induction coil; and  
         [0010]     (d) at least one power supply for supplying current to said at least one induction coil to heat said thermal transmitter wherein said heating system is used for heating fluids.  
         [0011]     The features of this invention will be apparent from the following description. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0012]      FIG. 1  is a schematic diagram of a preferred embodiment of the present invention. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0013]     As noted above, the present invention relates to a system and method for heating fluids in which induction heating is employed in an efficient manner to provide for an effective fluid heater.  
         [0014]     “Fluid” is herein defined as one or more substances, as a liquid or gas, that is capable of flowing and that changes its shape at a steady rate when acted upon by a force tending to change its shape.  
         [0015]      FIG. 1  illustrates a preferred embodiment of the present invention. In this preferred embodiment, inductively heated system  50  is used for heating fluids to a desired temperature. The desired temperature will be dependent on the type of operation is which the heating system is used. In addition, the design of the heating system can be modified to be used in almost any system in which fluids are heated.  
         [0016]     The preferred embodiment of the heating system  50  depicted in  FIG. 1  shows an enclosure  51 , thermal transmitters  52 , induction coil  53 , and filter  55 . The filter on this heating system is optional.  
         [0017]     The fields of use of the design depicted in  FIG. 1  can include any uses or operations wherein it is desired to heat a fluid stream to a desired temperature. For example, this technology can be utilized in such applications that include but are not limited to, an on-demand hot water heater for personal or industrial use, a steam generator, a pre-heater, a heat exchanger, a scrubber or absorption unit, a reactor or any like device wherein it is desired to efficiently and quickly heat a fluid.  
         [0018]     In this embodiment, enclosure  51  would be made of a substantially non-electrically conductive material. Preferably enclosure  51  is substantially made of a ceramic material or a composite thereof. Enclosure  51  is preferably at least partially surrounded by at least one induction coil  53  whereby induction heating is employed to heat a fluid to a desired temperature. The desired material used to build the enclosure will be substantially invisible to the electromagnetic energy generated by the induction coil  53  so that the electromagnetic energy may penetrate the enclosure to heat the thermal transmitters  52  discussed below in more detail.  
         [0019]     In a preferred embodiment, enclosure  51  is filled with thermal transmitters  52  which include, but are not limited to, geometric structures substantially made of a material that has a high electrical resistivity, a high melting point, and a thermal conductivity. Thermal transmitters  52  receive electromagnetic energy from induction coil  53  which preferably surrounds each individual enclosure  51 . Preferably, the induced electromagnetic energy is transmitted at an effective frequency that allows the energy to substantially penetrate enclosure  51  wherein the induction energy transmits substantially throughout the volume of thermal transmitters  52  so that the temperature of the thermal transmitters  52  may be as uniform as possible. As thermal transmitters  52  absorb the induced electromagnetic energy, thermal transmitters  52  are heated to an effective temperature that is sufficient to heat the fluid. The operating temperatures of the thermal transmitters  52  will depend entirely on the desired temperature of the outlet temperature of the fluid. The heating properties of the thermal transmitters  52  are attributable to their specific electrical conductivity and resistivity characteristics.  
         [0020]     Thermal transmitters  52  can be any suitable shape and size that will fit enclosure  51 . It is preferred that the thermal transmitters  52  be of a cork screw shape about one inch in diameter and about three inches in length. It is also preferred that the thermal transmitters will be placed into the heating system  50  in random order. Other shapes of thermal transmitters  52  that my be utilized in the heating system may include but are not limited to: (a) rasching rings; (b) Pall rings; (c) Berl saddles; and (d) Intalox saddles, which are all conventional shapes for tower packings.  
         [0021]     In another preferred embodiment, thermal transmitters  52  may be of a structured packing design wherein the structured packing will be comprised of an ordered geometry rather than a random packing configuration. This embodiment will also include a combination of structured and random packing configuration as it would be obvious to one skilled in the art to combine these two configurations.  
         [0022]     Preferably, the thermal transmitters  52  will have an electrical resistance higher than about 100 μohm-cm at 1800° F. and a thermal conductivity higher than about 195 BTU-in/ft 2  -hr-° F. at 1800° F. The melting point of thermal transmitters  52  is preferably higher than the operating temperature of inductively heated system  50  and most preferably about 50° F. higher than the operating temperature of inductively heated system  50 . In addition, the preferred melting point of thermal transmitters  52  is higher than about 1000° F., the more preferred is higher than about 1500° F., and the most preferred is higher than about 2000° F.  
         [0023]     The preferred material for thermal transmitters  52  is silicone carbide or a composite thereof. In addition, it is preferred that the material for thermal transmitters  52  be comprised of a substantially non-magnetizable material. It should be understood, however, that any other materials that meet the above referenced melting point, thermal conductivity, and electrical resistivity can be used for constructing thermal transmitters  52 . Thermal transmitters  52  may be of sufficient quantity and shape to disturb the flowing fluids sufficiently to knock out any entrained solid particles carried by the fluid stream thus acting as a particulate scrubber.  
         [0024]     In another preferred embodiment, heating system  50  can be operated in parallel with at least one additional heating system. In addition, although not shown in any of the figures, heating system  50  can be operated with at least one additional heating system placed in series with heating system  50 .  
         [0025]     In a preferred embodiment, a filter  55  is installed at about the outlet of the enclosure  5   1 . This filter is purely optional and the heating system can be operated without the filter  55 . This filter  55  is preferably made of materials which are compatible with or the same as thermal transmitters  52  wherein filter  55  will have an electrical resistance higher than about 100 μohm-cm at 1800° F. and a thermal conductivity higher than about 195 BTU-in/ft 2  -hr-° F. at 1800° F. The melting point of filter  55  is preferably higher than the operating temperature of inductively heated system  50  and most preferably about 50° F. higher than the operating temperature of induction heating system. Filter  55  will also preferably be comprised of a honeycomb structure capable of screening out at least a portion of any particulates that may have passed through induction heating system. Filter  55  may also be comprised of any effective structure that is suitable for screening out such particulates.  
         [0026]     In another preferred embodiment of the present invention, thermal transmitters  52  could be coated or impregnated with a catalyst to help drive various chemical reactions, including but not limited to an endothermic steam reforming reaction. In a reactive environment, it would be preferable to place a filter  55  in the heating system to capture any particulate. The inductively heated filter  55  could provide enough heat to cause the particulate to further react and exit the system. The filter would prevent particulates from entering a downstream process.  
         [0027]     Insofar as the description above and the accompanying drawings disclose any additional subject matter that is not within the scope of the claims below, the inventions are not dedicated to the public and the right to file one or more applications to claim such additional inventions is reserved.  
         [0028]     There are of course other alternate embodiments which are obvious from the foregoing descriptions of the invention, which are intended to be included within the scope of the invention, as defined by the following claims.