High temperature air heater and waste treatment equipment

Abstract

In an apparatus for heating high-temperature air for use in recovering, by heat exchange, the heat of an exhaust gas of elevated temperature generated from an apparatus for disposing of wastes, prolonged service life, improved working efficiency, improved efficiency of heat recovery on heat exchange are attainable with least thermal deformation and reduced dust deposition. Solving Means In the apparatus for heating high-temperature air located in a gas atmosphere of elevated temperature, an air to be heated and caused to flow through a heat transfer conduit is heated upon heat exchange with the gas of elevated temperature. The heat transfer coduit is constructed with a heat transfer pipe in which the air to be heated is flowed, and a refractory protective pipe held in coaxially covered relation to the heat transfer pipe with a gapping defined between both pipes. The refractory protective pipe is formed to be angular when seen sectionally, and the heat transfer pipe is disposed in a plural number and secured in face-to-face contact with adjoining heat transfer pipes and one sectionally angular face of the refractory protective pipe.

1 . An apparatus for heating high-temperature air characterized in that the apparatus is located in an atmosphere containing a gas of elevated temperature and has a heat transfer conduit disposed to heat, upon heat exchange with the gas of elevated temperature, an air to be heated and caused to flow through the heat transfer conduit, and the heat transfer conduit comprises a heat transfer pipe, or heat transfer pipes, arranged to flow the air to be heated therethrough, and a refractory protective pipe formed of refractory material and held in coaxially covered relation to the heat transfer pipe with a gapping defined between the heat transfer pipe and the refractory protective pipe.  
     
     
         2 . An apparatus for heating high-temperature air characterized in that the apparatus is located in an atmosphere containing a gas of elevated temperature and has a heat transfer conduit disposed to heat, upon heat exchange with the gas of elevated temperature, an air to be heated and caused to flow through the heat transfer conduit, and the heat transfer conduit comprises an inner heat transfer pipe formed of a metal and opened at its tip end, and an outer heat transfer pipe formed of a refractory material and held in coaxially covered relation to the inner metallic heat transfer pipe with a gap passage defined between the inner heat transfer pipe and the outer heat transfer pipe, and after being caused to flow through the inner heat transfer pipe, the air to be heated is heated with the gas of elevated temperature while the air to be heated is being passed at from the open tip end of the inner heat transfer pipe through the gap passage between the inner heat transfer pipe and the outer heat transfer pipe.  
     
     
         3 . An apparatus for heating high-temperature air according to  claim 1  or  2 , characterized in that the refractory protecting pipe or the outer refractory heat transfer pipe is structure to have an angular face in cross section, and the heat transfer conduit is disposed in a plural number and fixed in face-to-face contact with the adjoining refractory protective pipe or the outer refractory heat transfer pipe at its sectional angular face.  
     
     
         4 . An apparatus for heating high-temperature air according to  claim 1  or  3 , characterized in that the heat transfer pipe of the heat transfer conduit comprises an inner heat transfer pipe formed of a metal, and an outer heat transfer pipe formed of a metal and held in covered relation to the inner metallic heat transfer pipe with a spacing defined between the two pipes, the air to be heated is heated with the gas of elevated temperature while the air to be heated is being passed through the spacing between the inner and outer pipes, and the protective refractory pipe is arranged to cover the outer metallic heat transfer pipe and disposed coaxially of the latter pipe with a gapping defined between the protective pipe and the outer pipe.  
     
     
         5 . An apparatus for heating high-temperature air according to  claim 1  or  3 , characterized in that the heat transfer pipe of the heat transfer conduit comprises an outer heat transfer pipe formed of a metal, and an inner pipe arranged to communicate with one end of the outer pipe with a spacing defined between the outer and inner pipes, and the inner pipe is formed into a thermally insulated structure with lower thermal conductivity than the metal, and the air to be heated is heated with the gas of elevated temperature along an outer wall of the outer metallic heat transfer pipe while the air to be heated is being passed through the spacing between the outer metallic heat transfer pipe and the inner thermally insulating pipe.  
     
     
         6 . An apparatus for heating high-temperature air according to  claim 5 , characterized in that the inner pipe is formed of a thermally insulating material of low thermal conductivity other than a metal.  
     
     
         7 . An apparatus for heating high-temperature air according to  claim 5 , characterized in that the inner pipe is brought into a thermally insulated structure in which the thermally insulating material is sandwiched with metallic tubes.  
     
     
         8 . An apparatus for heating high-temperature air according to  claim 5 , characterized in that the inner pipe is brought into a thermally insulated structure in which the inner pipe is formed of a metal and in a double-piped vacuum-drawn arrangement.  
     
     
         9 . An apparatus for heating high-temperature air according to  claim 6  or  7 , characterized in that the thermally insulating material is ceramics.  
     
     
         10 . An apparatus for heating high-temperature air according to any one of claim  4 - 9 , characterized in that the air to be heated is caused to flow in a direction reverse to that of the gas of elevated temperature through the spacing between the inner pipe and the outer pipe, both of which are arranged to constitute the heat transfer conduit.  
     
     
         11 . An apparatus for heating high-temperature air according to any one of  claim 1 ,  3 - 9 , characterized in that a plurality of support materials are fixedly placed outwardly of the heat transfer pipe to thereby support the refractory protective pipe.  
     
     
         12 . An apparatus for heating high-temperature air according to any one of claims  4 - 11 , characterized in that the gapping is defined to communicate with a passage for the flow of the air to be heated with a through hole made in a wall of the outer metallic heat transfer pipe.  
     
     
         13 . An apparatus for heating high-temperature air according to any one of claims  1 - 12 , characterized in that a partitioned space is defined at a region where a tip end of the heat transfer pipe is opposed to a tip end of the refractive protective pipe or the refractory heat transfer pipe, and the air to be heated is introduced into the space partitioned at the tip ends of the two pipes.  
     
     
         14 . An apparatus for heating high-temperature air according to any one of claims  4 - 11 , characterized in that means is disposed for introducing an extraneous air into the spacing between the refractory protective pipe and the outer metallic heat transfer pipe.  
     
     
         15 . An apparatus for heating high-temperature air according to  claim 14 , characterized in that a partitioned space is defined at a region where a tip end of the outer metallic heat transfer pipe is opposed to a tip end of the refractory protective pipe, and the extraneous air is introduced into the space partitioned at the tip ends of the two pipes.  
     
     
         16 . An apparatus for heating high-temperature air according to any one of claims  1 - 15 , characterized in that the tip end of the refractory protective pipe or the outer refractory heat transfer pipe is formed in a convex shape so as to be less resistant to the flow of the gas of elevated temperature.  
     
     
         17 . An apparatus for heating high-temperature air according to  claim 16 , characterized in that the convex shape is of a semispherical shape.  
     
     
         18 . An apparatus for heating high-temperature air according to  claim 16 , characterized in that the convex shape is of a conical shape.  
     
     
         19 . An apparatus for heating high-temperature air according to  claim 16 , characterized in that the convex shape is of a polyherral convex shape.  
     
     
         20 . An apparatus for heating high-temperature air according to  claim 16 , characterized in that the convex shape is of a polyheral convex shape is of a convexity shaped by a planar face and either one or both curved faces.  
     
     
         21 . An apparatus for heating high-temperature air according to any one of claim  16 - 20 , characterized in that the refractory protective pipe or the outer refractory heat transfer pipe of the heat transfer conduit is shaped like a circular pillar when seen sectionally, and either of the pipes is formed to be smoothly extensive from its convex tip end to its base end.  
     
     
         22 . An apparatus for heating high-temperature air according to any one of claim  16 - 20 , characterized in that the refractory protective pipe or the outer refractory heat transfer pipe of the heat transfer conduit is shaped like a tetraherdal pillar when seen sectionally, and either of the pipes is formed to be smoothly extensive from its convex tip end to its base end.  
     
     
         23 . An apparatus for heating high-temperature air according to any one of claim  1 - 15 , characterized in that the tip end of the refractory protective pipe or the outer refractory heat transfer pipe is formed as a refractory removable cap.  
     
     
         24 . An apparatus for heating high-temperature air according to any one of claim  1 - 15 , characterized in that the cap is formed in a convex shape so as to be less resistant to the flow of the gas of elevated temperature.  
     
     
         25 . An apparatus for heating high-temperature air according to any one of claim  1 - 15 , characterized in that the cap is screwed to the tip end of the heat transfer pipe with a space defined at an opposed tip end, the screwing is effected with a partial gap, and the heat transfer pipe is provided at its tip end with a through hole for the air to be caused to pass therethrough to be partly flowed into the space.  
     
     
         26 . An apparatus for heating high-temperature air according to any one of claim  23 - 25 , characterized in that the refractory protective pipe or the outer refractory heat transfer pipe of the heat transfer conduit is shaped like a circular pillar when seen sectionally, and the cap and either of the pipes are connected to each other in an externally smoothly coextensive manner.  
     
     
         27 . An apparatus for heating high-temperature air according to any one of claim  23 - 25 , characterized in that the refractory protective pipe or the outer refractory heat transfer pipe of the heat transfer conduit is shaped like a tetrahedral pillar when seen sectionally, and the cap and either of the pipes are connected to each other in an externally smoothly coextensive manner.  
     
     
         28 . An apparatus for heating high-temperature air according to any one of claim  1 - 27 , characterized in that the apparatus comprises a first air heater positioned upstream of a passage for the flow of the gas of elevated temperature, and a second air heater positioned downstream of the flow passage, the air to be heated is supplied to and heated in the second air heater, and the resultant air is then transported to and in the first air heater.  
     
     
         29 . An apparatus for heating high-temperature air according to any one of claim  1 - 27 , characterized in that the apparatus comprises a first air heater positioned upstream of a passage for the flow of the gas of elevated temperature, and a second air heater positioned downstream of the flow passage, the air to be heated is supplied to and heated in the first and second air heaters, respectively, and two sorts of the air heated are combined together and then taken outside.  
     
     
         30 . An apparatus for heating high-temperature air according to  claim 29 , characterized in that the air to be heated is partly supplied through either one of the first air heater-constituting heat transfer pipe or the outer pipe and the inner pipe, and the remaining portion of the the air to be heated is supplied through either one of the second air heater-constituting heat transfer pipe or the outer pipe and the inner pipe to and heated in either the inner pipe or the outer pipe.  
     
     
         31 . A partition wall for use in a heat exchanger in which the partition wall is disposed to separate an air passage from an exhaust gas passage, characterized in that the partition wall comprises a metallic wall placed in contact on one side with the gas passage, a first spacing is defined between the outer side of the metallic wall and the other side of the refractory wall and made to communicate with a through hole made in the metallic wall, thereby flowing a burnt exhaust gas containing corrosive components and dust into the exhaust gas passage, and a plurality of support materials are securely attached to the other side of the metallic wall so as to support the refractory wall.  
     
     
         32 . A partition wall for use in a heat exchanger according to  claim 31 , characterized in that a second spacing is defined between the support materials and the refractory wall and made to communicate with the first spacing.  
     
     
         33 . A process for producing a partition wall for use in a heat exchanger in which the partition wall is disposed to separate an air passage from an exhaust gas passage, the partition wall comprising a metallic wall placed in contact on one side with the air passage, and a refractory wall placed in contact on side with the gas passage, a first spacing is defined between the other side of the metallic wall and the other side of the refractory wall and made to communicate with a through hole made in the metallic wall, thereby flowing a burnt exhaust gas containing corrosive components and dust into the exhaust gas passage, and a plurality of support materials are securely attached to the other side of the metallic wall so as to support the refractory wall, characterized in that the process comprises the steps of disposing an interlaminar material over the other side of the metallic wall by covering vinyl sheet or paper tape thereover, or by coating tar or paint thereover, coating or spraying over the interlaminar material a water-containing castable material to dry and calcine the same to thereby form the refractory wall and to remove the interlaminar material therefrom, and subsequently defining the first spacing on the refractory wall where the interlaminar has been removed.  
     
     
         34 . A process for producing a partition wall for use in a heat exchange in which a second spacing is defined between the support materials and the refractory wall and made to communicate with the first spacing, characterized in the process comprises the steps of disposing an interlaminar material over the support materials, prior to or after welding of the support materials to the metallic wall, by winding insulating tape made of polyvinyl chloride thereover, by covering vinyl hose cut short thereover, by coating or spraying over the interlaminar material a water-containing castable material to dry and calcine the same to thereby form the refractory wall and to remove the interlaminar material therefrom, and susequently defining the second spacing on the support materials where the interlaminar material has been removed.  
     
     
         35 . An apparatus for disposing of wastes which is provided with a thermally decomposition reactor in which wastes are thermally decomposed to generate a thermally decomposed gas and a thermally decomposed residue, a separator in which the thermally decomposed residue is separated into combustible components and incombustible components, a burning melting furnace in which the thermally decomposed gas and the combustble components are burnt at a temperature at which to melt ash to thereby discharge incombustible matter as molten slug, and an apparatus for heating high-temperature air in which the heat of gas of elevated temperature is recovered by heat exchange with air, characterized in that the apparatus for heating high-temperature air is set forth in any one of claims  1 - 30 .