EP0063195A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Exhaust gas treatment method and apparatus
Assignee: Heat Exchanger Industries Inc
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Filing: 1981-10-15
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Granted: —
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Expires: 2001-10-15
Abstract
Abstract Exhaust gas treatment method and apparatus extract heat from an exhaust gas by operating in a water-condensing mode which allows more heat to be recovered, removes particulate matter and condensed acid from the exhaust gas, and washes heat exchange surfaces to keep them clean and wet to improve heat transfer. Systems for heating water, air, and both water and air are disclosed. Methods of constructing and assembling improved heat exchangers are disclosed.
Inventors
- 👤 Donald F. Warner
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-30 17:13
CPC Classifications
B; B01; B01D; B01D53/00; B01D53/34; B01D53/46; B01D53/48; B01D53/50; B01D53/507; B01D53/002; B01D53/005; F; F23; F23J; F23J15/00; F23J15/06; F28; F28D; F28D21/00; F28D21/0001; F28D21/0003; F28D21/001; F28D7/00; F28D7/08; F28D7/082; F28D7/085; F28D7/16; F28D7/1615; F28D7/1623; F28F; F28F19/00; F28F19/02; F28F19/04; F28F9/00; F28F9/007; F28F9/013; F28F9/0131; F28F9/02; F28F9/04; F28F9/06; F28F9/14; F28F9/26; Y; Y02; Y02E; Y02E20/00; Y02E20/30; Y10; Y10S; Y10S165/00; Y10S165/905; Y10S165/909
Claims Analysis
Total Claims: 43
Claim 1
Independent Claim
230 words
A method of recovering heat energy contained in a hot exhaust gas which contains water vapor, sulfur trioxide and particulate matter, and of simultaneously removing substantial amounts of said particulate matter and sulfur trioxide from the exhaust gas which comprises the steps of: passing said exhaust gas in heat exchange relationship upwardly between tubes of a tube nest; and simultaneously passing a fluid downwardly through tubes of said nest, the temperature and flow rate of said fluid being selected in relation to the input temperature and flow rate of said exhaust gas and the heat exchange surface of said nest so that the temperature of said fluid within an upper group of said tubes remains below 120°F, thereby causing continuous substantial condensation of water from said exhaust gas as said gas passes said upper group of tubes and a continuous fall of condensate from said upper group of tubes to wash lower tubes of said nest, whereby a substantial portion of the latent heat energy in said hot exhaust gas is transferred to said fluid, the wetting of said tubes from condensation causes portions of said particulate matter to temporarily stick to tubes of said tube nest, and the continuous fall of condensation entraps portions of particulate matter, washes particulate matter and sulfuric acid from tubes, and dilutes sulfuric acid formed by condensation at lower portions of said tube nest.
Claim 2
Independent Claim
230 words
A method of recovering heat energy contained in a hot exhaust gas which contains water vapor, sulfur trioxide and particulate matter, and of simultaneously removing substantial amounts of said particulate matter and sulfur trioxide from the exhaust gas which comprises the steps of: passing said exhaust gas in heat exchange relationship upwardly between tubes of a tube nest; and simultaneously passing a fluid downwardly through tubes of said nest, the temperature and flow rate of said fluid being selected in relation to the input temperature and flow rate of said exhaust gas and the heat exchange surface of said nest so that the temperature of said fluid within an upper group of said tubes remains below 120°F, thereby causing continuous substantial condensation of water from said exhaust gas as said gas passes said upper group of tubes and a continuous fall of condensate from said upper group of tubes to wash lower tubes of said nest, whereby a substantial portion of the latent heat energy in said hot exhaust gas is transferred to said fluid, the wetting of said tubes from condensation causes portions of said particulate matter to temporarily stick to tubes of said tube nest, and the continuous fall of condensation entraps portions of particulate matter, washes particulate matter and sulfuric acid from tubes, and dilutes sulfuric acid formed by condensation at lower portions of said tube nest.
Claim 3
Dependent Claim
32 words
2, A method as claimed in claim 1, wherein said exhaust gas is directed upwardly through said tube nest at a velocity within the range of 30 to 60 feet per second.
Claim 4
Dependent Claim
44 words
A method as claimed in claim 1 wherein said exhaust gas is passed upwardly through a housing containing said nest of tubes, with a pressure drop within the range of 1 to 3 inches of water occurring in said exhaust gas within said housing.
Claim 5
Dependent Claim
27 words
A method as claimed in claim 1 wherein said tubes of said tube nests are staggered, so that condensate dropping from upper tubes splashes on lower tubes.
Claim 6
Dependent Claim
26 words
A method as claimed in claim 1 which includes the step of continuously removing condensate mixed with particulate matter which has fallen below said tube nest.
Claim 7
Dependent Claim
40 words
A method as claimed in claim 1 which includes the steps of monitoring said input temperature of said exhaust gas and mixing a cooler gas with said hot exhaust gas to prevent said input temperature from exceeding a predetermined value.
Claim 8
Dependent Claim
29 words
A method as claimed in claim 1 which includes the step of periodically directing a spray of liquid onto said nest of tubes from above said nest of tubes.
Claim 9
Dependent Claim
46 words
A method as claimed in claim 1 wherein said fluid passed through tubes comprises water, and said method includes the step of supplying water to said tubes from a hot water storage means and the step of supplying water from said tubes to said storage means.
Claim 10
Dependent Claim
43 words
A method as claimed in claim 1 which includes the step of varying the amount of said exhaust gas being passed between said tubes of said nest to maintain the temperature of gas exiting upwardly above said tube nest at a predetermined value.
Claim 11
Dependent Claim
47 words
A method as claimed in claim 1 which includes the steps of sensing the outlet temperature of said fluid, and varying the amount of said exhaust gas being passed between said tubes of said nest to maintain said outlet temperature of said fluid at a predetermined value.
Claim 12
Dependent Claim
146 words
Apparatus for recovering heat energy from an exhaust gas which contains water vapor and sulfur-trioxide, comprising in combination: means defining a gas passage housing; a plurality of tubes extending generally horizontally through said gas passage housing at a plurality of different levels, the inside of said gas passage and the exterior surfaces of said tubes within said gas passage housing carrying corrosion-protecting coverings; means for applying said exhaust gas to said gas passage housing for upward flow of said exhaust gas between said tubes and through said housing; and means for passing a fluid which is cooler than 90OF downwardly through successive ones of said tubes, thereby causing continuous condensation of water vapor after condensation of sulfuric acid as said exhaust gas travels upwardly through said housing and a continuous washing of lower tubes in said housing by condensate falling from upper levels within said housing.
Claim 13
Dependent Claim
146 words
Apparatus for recovering heat energy from an exhaust gas which contains water vapor and sulfur-trioxide, comprising in combination: means defining a gas passage housing; a plurality of tubes extending generally horizontally through said gas passage housing at a plurality of different levels, the inside of said gas passage and the exterior surfaces of said tubes within said gas passage housing carrying corrosion-protecting coverings; means for applying said exhaust gas to said gas passage housing for upward flow of said exhaust gas between said tubes and through said housing; and means for passing a fluid which is cooler than 90OF downwardly through successive ones of said tubes, thereby causing continuous condensation of water vapor after condensation of sulfuric acid as said exhaust gas travels upwardly through said housing and a continuous washing of lower tubes in said housing by condensate falling from upper levels within said housing.
Claim 14
Dependent Claim
50 words
Apparatus as claimed in claim 11 which includes a stack, and upper housing means situated above said gas passage housing to convey said exhaust gas from the upper end of said gas passage housing to said stack, said upper housing means and said stack being formed of acid-resistant reinforced fiberglass.
Claim 15
Dependent Claim
51 words
Apparatus as claimed in claim 11 which includes lower housing means situated below said gas passage housing to collect condensate and to convey said exhaust gas into the lower end of said gas passage housing, said lower housing means including drain means for draining said condensate from said lower housing means.
Claim 16
Dependent Claim
44 words
Apparatus as claimed in claim 11 wherein said means for applying said exhaust gas to said gas passage housing includes a blower to provide a flow velocity of said exhaust gas inside said housing within the range of 30 to 60 feet per second.
Claim 17
Dependent Claim
55 words
Apparatus as claimed in claim 11 which includes means for mixing air with said exhaust gas prior to application of said exhaust gas to said gas passage housing to limit the temperature of gas passed into said gas passage housing to a temperature below a predetermined material limit temperature of one of said corrosion-protecting coverings.
Claim 18
Dependent Claim
34 words
16, Apparatus as claimed in claim 11 which includes means for automatically terminating application of said exhaust gas to said gas passage housing if the temperature of said exhaust gas exceeds a predetermined value.
Claim 19
Dependent Claim
26 words
Apparatus as claimed in claim 11 which includes means for decreasing flue gas flow if the temperature of said fluid begins to exceed a predetermined value.
Claim 20
Dependent Claim
27 words
Apparatus as claimed in claim 11 wherein said tubes comprise copper tubes each having their exterior surface carrying a layer of Teflon less than 30 mils thick.
Claim 21
Dependent Claim
27 words
Apparatus as claimed in claim 11 wherein said tubes comprise aluminum tubes each having their exterior surface carrying a layer of Teflon less than 30 mils thick.
Claim 22
Dependent Claim
47 words
Apparatus as claimed in claim 11 which includes a heat exchanger connected to conduct said exhaust gas to said gas passage housing, and means for controlling flow of a fluid through said heat exchanger to control the temperature of the exhaust gas conducted to said gas passage.
Claim 23
Independent Claim
245 words
The method of recovering heat energy from an exhaust gas by heating a fluid wherein said exhaust gas includes water vapor condensable at and below a water vapor condensation temperature and a corrosive constituent condensable at and below a corrosive condensation temperature, which is higher than said water vapor condensation temperature, said method comprising the steps of passing said exhaust gas successively through a first heat exchanger and a second heat exchanger, said second heat exchanger containing corrosion-potection material having a material limit operating temperature exceeding said corrosive condensation temperature, the flow rates and temperatures of said exhaust gas and said fluid being arranged so that passage of said exhaust gas through said first heat exchanger cools said exhaust gas from a first temperature to a second temperature which is below said material limit operating temperature but above said corrosive condensation temperature, passage of said exhaust gas through said second heat exchange cools said exhaust gas from a temperature above said corrosive condensation temperature to a third temperature below said water vapor condensation temperature, and passage of said fluid through said second heat exchanger heats said fluid from a temperature below said water vapor condensation temperature to a fourth temperature which is above said corrosive condensation temperature but below said material limit operating temperature, whereby condensation of both water vapor and said corrosive constituent continuously occur within said second heat exchanger and neither water vapor nor said corrosive constituent condense within said first heat exchanger.
Claim 24
Independent Claim
245 words
The method of recovering heat energy from an exhaust gas by heating a fluid wherein said exhaust gas includes water vapor condensable at and below a water vapor condensation temperature and a corrosive constituent condensable at and below a corrosive condensation temperature, which is higher than said water vapor condensation temperature, said method comprising the steps of passing said exhaust gas successively through a first heat exchanger and a second heat exchanger, said second heat exchanger containing corrosion-potection material having a material limit operating temperature exceeding said corrosive condensation temperature, the flow rates and temperatures of said exhaust gas and said fluid being arranged so that passage of said exhaust gas through said first heat exchanger cools said exhaust gas from a first temperature to a second temperature which is below said material limit operating temperature but above said corrosive condensation temperature, passage of said exhaust gas through said second heat exchange cools said exhaust gas from a temperature above said corrosive condensation temperature to a third temperature below said water vapor condensation temperature, and passage of said fluid through said second heat exchanger heats said fluid from a temperature below said water vapor condensation temperature to a fourth temperature which is above said corrosive condensation temperature but below said material limit operating temperature, whereby condensation of both water vapor and said corrosive constituent continuously occur within said second heat exchanger and neither water vapor nor said corrosive constituent condense within said first heat exchanger.
Claim 25
Dependent Claim
15 words
The method of claim 21 wherein said first temperature exceeds said material limit operating temperature.
Claim 26
Dependent Claim
29 words
The method of claim 21 wherein passage of said fluid through said first heat exchanger heats said fluid to a temperature which is above said material limit operating temperature.
Claim 27
Dependent Claim
53 words
The method of claim 21 wherein said fluid is air and which method includes the step of applying said exhaust gas to said first heat exchanger from a fuel-burning means which produces said exhaust gas, and the step of applying air heated by first heat exchanger as combustion air to said fuel-burning means.
Claim 28
Dependent Claim
58 words
The method of claim 21 which includes passing said fluid upwardly through said second heat exchanger, whereby condensation of water vapor occurs at a higher level within said second heat exchanger than condensation of said corrosive constituent and gravitational fall of condensed water vapor washes condensed corrosive constituent from lower heat exchange surfaces in said second heat exchanger.
Claim 29
Dependent Claim
19 words
A method as claimed in claim 21 which includes the step of draining condensation from said second heat exchanger.
Claim 30
Dependent Claim
217 words
Apparatus for recovering heat energy from an exhaust gas by heating a fluid, wherein said exhaust gas includes water vapor condensable at and below a water vapor condensation temperature and a corrosive constituent condensable at and below a corrosive constituent condensation temperature which is higher than said water vapor condensation temperature, comprising in combination: a first heat exchanger having a gas passage lined with corrosion-resistant material having a deformation temperature which is less than the initial temperature of said exhaust gas but greater than said corrosive constituent condensation temperature, and a fluid passage in heat exchange relationship with said gas passage; a second heat exchanger susceptible to damage by the condensed corrosive constituent, said second heat exchanger being connected to receive said exhaust gas at said initial temperature, to cool said gas to a second temperature which is below said deformation temperature but above said corrosive constituent condensation temperature, and to supply said exhaust gas to said gas passage of said first heat exchanger; and means for establishing the flow rates of said exhaust gas through said first and second heat exchangers and the flow rate of said fluid through said first heat exchanger so that condensation of water vapor occurs continuously in said first heat exchanger and condensation does not occur in said second heat exchanger.
Claim 31
Dependent Claim
217 words
Apparatus for recovering heat energy from an exhaust gas by heating a fluid, wherein said exhaust gas includes water vapor condensable at and below a water vapor condensation temperature and a corrosive constituent condensable at and below a corrosive constituent condensation temperature which is higher than said water vapor condensation temperature, comprising in combination: a first heat exchanger having a gas passage lined with corrosion-resistant material having a deformation temperature which is less than the initial temperature of said exhaust gas but greater than said corrosive constituent condensation temperature, and a fluid passage in heat exchange relationship with said gas passage; a second heat exchanger susceptible to damage by the condensed corrosive constituent, said second heat exchanger being connected to receive said exhaust gas at said initial temperature, to cool said gas to a second temperature which is below said deformation temperature but above said corrosive constituent condensation temperature, and to supply said exhaust gas to said gas passage of said first heat exchanger; and means for establishing the flow rates of said exhaust gas through said first and second heat exchangers and the flow rate of said fluid through said first heat exchanger so that condensation of water vapor occurs continuously in said first heat exchanger and condensation does not occur in said second heat exchanger.
Claim 32
Dependent Claim
84 words
Apparatus as claimed in claim 27 wherein said second heat exchanger includes a fluid passage and a gas passage in heat exchange relationship thereto, said apparatus including means for applying said fluid from said first heat exchanger to the fluid passage of said second heat exchanger, said first heat exchanger being operable to heat said fluid from a temperature which is below said water vapor condensation temperature to a third temperature which is above said corrosive constituent condensation temperature but below said deformation temperature.
Claim 33
Dependent Claim
24 words
Apparatus as claimed in claim 28 wherein said second heat exchanger is operative to heat said fluid to a temperature exceeding said deformation temperature.
Claim 34
Dependent Claim
38 words
Apparatus as claimed in claim 28 which includes a combustion source which bums combustion air to provide said exhaust gas, and means for conducting said fluid to said combustion source to supply combustion air to said combustion source.
Claim 35
Dependent Claim
163 words
Apparatus for extracting heat energy from a hot exhaust gas containing water vapor to heat air and water comprising, in combination: means defining a gas passage housing; means for passing said exhaust gas upwardly through said gas passage housing; a first plurality of tubes extending through a lower portion of said gas passage housing; a second plurality of tubes extending through an upper portion of said gas passage housing, the interior of said housing and the exterior surfaces of said tubes within said housing carrying plastic corrosion-protection coverings; means for passing air to be heated through said first plurality of tubes; and means for passing water to be heated through said second plurality of tubes, the temperature of said water in a group of said tubes of said second plurality being maintained below the condensation temperature of said water vapor, whereby condensation occurring on tubes of said second plurality continuously falls within gas passage housing to wet the tubes of said first plurality.
Claim 36
Dependent Claim
163 words
Apparatus for extracting heat energy from a hot exhaust gas containing water vapor to heat air and water comprising, in combination: means defining a gas passage housing; means for passing said exhaust gas upwardly through said gas passage housing; a first plurality of tubes extending through a lower portion of said gas passage housing; a second plurality of tubes extending through an upper portion of said gas passage housing, the interior of said housing and the exterior surfaces of said tubes within said housing carrying plastic corrosion-protection coverings; means for passing air to be heated through said first plurality of tubes; and means for passing water to be heated through said second plurality of tubes, the temperature of said water in a group of said tubes of said second plurality being maintained below the condensation temperature of said water vapor, whereby condensation occurring on tubes of said second plurality continuously falls within gas passage housing to wet the tubes of said first plurality.
Claim 37
Dependent Claim
130 words
Heat exchanger apparatus, comprising, in combination: a pair of side members and a pair of metal tube sheets defining a generally rectangular housing, each of said tube sheets having a plurality of holes; a pair of plastic sheets covering the inside surfaces of respective ones of said tube sheets with portions of said plastic sheets extending through each of said holes in said tube sheets to the outside of the tube sheets; and a plurality of metal tubes having plastic exterior coverings, each of said metal tubes extending through respective holes in both of said tube sheets and being mechanically fixed in place by the gripping of its exterior plastic covering by the portions of the plastic sheets which extend through the tube sheet holes which the metal tube extends.
Claim 38
Dependent Claim
130 words
Heat exchanger apparatus, comprising, in combination: a pair of side members and a pair of metal tube sheets defining a generally rectangular housing, each of said tube sheets having a plurality of holes; a pair of plastic sheets covering the inside surfaces of respective ones of said tube sheets with portions of said plastic sheets extending through each of said holes in said tube sheets to the outside of the tube sheets; and a plurality of metal tubes having plastic exterior coverings, each of said metal tubes extending through respective holes in both of said tube sheets and being mechanically fixed in place by the gripping of its exterior plastic covering by the portions of the plastic sheets which extend through the tube sheet holes which the metal tube extends.
Claim 39
Dependent Claim
97 words
Apparatus as claimed in claim 32 having a pair of plastic sheets covering the inside surfaces of respective ones of said side members and wherein said tube sheets include a pair of flanges, each of said plastic sheets covering the inside surface of one of said tube sheets being formed to extend from said inside surface to cover at least a portion of each flange, said side members and said tube sheets being fastened together so that portions of the plastic sheets covering said side members are seated against portions of the plastic sheets covering said flanges.
Claim 40
Independent Claim
128 words
A method of conserving heat energy and removing particulate matter from exhaust gas produced by a direct-fired dryer apparatus which is operative to produce heated air from combustion of fuel with input air and operative to apply said heated air in a drying process, thereby providing an exhaust gas carrying particles and sulfur trioxide, said method comprising the steps of passing said exhaust gas upwardly between tubes of a nest of tubes in a heat exchanger, and passing ambient air into and through said tubes to provide input makeup air for said direct-fired dryer apparatus, thereby causing condensation of sulfurio acid and entrapment of particles at one elevational level within said heat exchanger, and continuous condensation of water vapor at a higher elevational level within said heat exchanger.
Claim 41
Independent Claim
128 words
A method of conserving heat energy and removing particulate matter from exhaust gas produced by a direct-fired dryer apparatus which is operative to produce heated air from combustion of fuel with input air and operative to apply said heated air in a drying process, thereby providing an exhaust gas carrying particles and sulfur trioxide, said method comprising the steps of passing said exhaust gas upwardly between tubes of a nest of tubes in a heat exchanger, and passing ambient air into and through said tubes to provide input makeup air for said direct-fired dryer apparatus, thereby causing condensation of sulfurio acid and entrapment of particles at one elevational level within said heat exchanger, and continuous condensation of water vapor at a higher elevational level within said heat exchanger.
Claim 42
Independent Claim
158 words
A method. of fabricating a heat exchanger which comprises the steps of: heat-forming edge portions of holes in a plastic sheet having a plurality of holes to extend through. and line holes in an adjacent metal sheet having holes which concentrically register with respective holes in said plastic sheet, thereby to form a plastic-lined metal sheet assembly; inserting plug means in each hole before the plastic lining has cooled to limit diametrical reduction of the plastic-lined holes; spacing a pair of said plastic-lined metal sheet assemblies fixedly apart and parallel to each other; and entering an end of a plastic-covered tube successively through a plastic-lined hole in each of said plastic-lined metal sheet assemblies sufficiently shortly after removal of the plug means from said holes that the progressive diametrical reduction of said plastic-lined holes allows said end to be entered thraugh said plastic-lined holes but then causes said plastic-lined holes to grip and fixedly locate said plastic-covered tube.
Claim 43
Independent Claim
158 words
A method. of fabricating a heat exchanger which comprises the steps of: heat-forming edge portions of holes in a plastic sheet having a plurality of holes to extend through. and line holes in an adjacent metal sheet having holes which concentrically register with respective holes in said plastic sheet, thereby to form a plastic-lined metal sheet assembly; inserting plug means in each hole before the plastic lining has cooled to limit diametrical reduction of the plastic-lined holes; spacing a pair of said plastic-lined metal sheet assemblies fixedly apart and parallel to each other; and entering an end of a plastic-covered tube successively through a plastic-lined hole in each of said plastic-lined metal sheet assemblies sufficiently shortly after removal of the plug means from said holes that the progressive diametrical reduction of said plastic-lined holes allows said end to be entered thraugh said plastic-lined holes but then causes said plastic-lined holes to grip and fixedly locate said plastic-covered tube.
References Cited (Backward Citations)
No citation records indexed.
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