US4487139A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Exhaust gas treatment method and apparatus
Assignee: Heat Exchanger Industries Inc
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Filing: 1982-08-10
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Granted: 1984-12-11
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Expires: 2002-08-10
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
US
Data Source
google_patents
Last Synchronized
2026-10-29 03:32
CPC Classifications
F; F28; F28D; F28D7/00; F28D7/08; F28D7/082; F28D7/085; B; B01; B01D; B01D53/00; B01D53/002; B01D53/34; B01D53/46; B01D53/48; B01D53/50; B01D53/507; F23; F23J; F23J15/00; F23J15/06; F28D21/00; F28D21/0001; F28D21/0003; F28D21/001; F28D7/16; F28D7/1615; F28D7/1623; F28F; F28F19/00; F28F19/02; F28F19/04; F28F9/00; F28F9/007; F28F9/013; F28F9/0131; Y; Y02; Y02E; Y02E20/00; Y02E20/30; Y10; Y10S; Y10S165/00; Y10S165/905
Claims Analysis
Total Claims: 35
Claim 1
Independent Claim
266 words
The method of recovering heat energy contained in a hot exhaust gas containing water vapor and sulfur trioxide combinable in part to form sulfuric acid, and of simultaneously removing substantial amounts of said sulfur trioxide from the exhaust gas, which comprises the steps of: passing said exhaust gas in heat exchange flow relationship generally perpendicularly to and between generally horizontally extending tubes of a tube nest having a plurality of tube groups; and simultaneously passing a fluid to be heated through successive tubes of said nest in counterflow relationship to said exhaust gas flow, the flow rate of said exhaust gas being established in relation to the input temperature and flow rate of said fluid and the heat exchange surface area of said nest so that the temperature of said fluid within a first group of said tubes remains substantially below the water vapor dewpoint of said exhaust gas, thereby transferring a substantial portion of the latent heat energy in said hot exhaust gas to said fluid and causing continuous substantial condensation of water from said exhaust gas and a continuous fall of water droplets from tubes of said first group through said exhaust gas to the tubes of a lower tube group, whereby said water droplets entrap and dilute sulfuric acid as they fall from said tubes of said first group through said exhaust gas, and said water droplets wash sulfuric acid from said tubes of said lower group, the exterior surfaces of said tubes of said tube nest being covered with coverings which both shield said tubes from sulfuric acid and promote dropwise condensation.
Claim 2
Independent Claim
266 words
The method of recovering heat energy contained in a hot exhaust gas containing water vapor and sulfur trioxide combinable in part to form sulfuric acid, and of simultaneously removing substantial amounts of said sulfur trioxide from the exhaust gas, which comprises the steps of: passing said exhaust gas in heat exchange flow relationship generally perpendicularly to and between generally horizontally extending tubes of a tube nest having a plurality of tube groups; and simultaneously passing a fluid to be heated through successive tubes of said nest in counterflow relationship to said exhaust gas flow, the flow rate of said exhaust gas being established in relation to the input temperature and flow rate of said fluid and the heat exchange surface area of said nest so that the temperature of said fluid within a first group of said tubes remains substantially below the water vapor dewpoint of said exhaust gas, thereby transferring a substantial portion of the latent heat energy in said hot exhaust gas to said fluid and causing continuous substantial condensation of water from said exhaust gas and a continuous fall of water droplets from tubes of said first group through said exhaust gas to the tubes of a lower tube group, whereby said water droplets entrap and dilute sulfuric acid as they fall from said tubes of said first group through said exhaust gas, and said water droplets wash sulfuric acid from said tubes of said lower group, the exterior surfaces of said tubes of said tube nest being covered with coverings which both shield said tubes from sulfuric acid and promote dropwise condensation.
Claim 3
Dependent Claim
23 words
The method of claim 1 wherein said coverings each comprise a layer of fluoroplastic having a thickness within the range of 2-30 mils.
Claim 4
Dependent Claim
27 words
The method of claim 1 wherein the amount of latent heat energy released by condensation exceeds 5 percent of the total heat energy transferred to said fluid.
Claim 5
Dependent Claim
28 words
The method of claim 1 wherein said step of passing said exhaust gas comprises forcing said exhaust gas through said tube nest by use of a blower means.
Claim 6
Dependent Claim
39 words
The method of claim 1 wherein said exhaust gas also initially contains particulate matter, whereby said water droplets entrap a portion of said particulate matter as they fall from said tubes of said first group through said exhaust gas.
Claim 7
Dependent Claim
29 words
The method of claim 1 which includes the step of introducing a scrubbing liquor into said exhaust gas prior to passage of said exhaust gas through said tube nest.
Claim 8
Dependent Claim
41 words
The method of claim 1 which includes the step of varying the amount of said exhaust gas being passed between said tubes of said tube nest to maintain the temperature of gas exiting from said tube nest at a predetermined value.
Claim 9
Dependent Claim
64 words
The method of claim 1 wherein said exhaust gas is passed generally downwardly through said tube nest, and said fluid being heated is passed through successively upward tubes of said nest, whereby said tubes of said first group contain warmer fluid than the tubes of said lower group, and the fall of said water droplets transfers heat to said tubes of said lower group.
Claim 10
Dependent Claim
31 words
The method of claim 1 wherein said exhaust gas is passed generally upwardly through said tube nest, and said fluid being heated is passed through successively downward tubes of said nest.
Claim 11
Dependent Claim
17 words
The method of claim 1 wherein said exhaust gas is forced generally horizontally through said tube nest.
Claim 12
Dependent Claim
37 words
The method of claim 1 which includes the step of substantially altering the direction of flow of said exhaust gas upon exit of said gas from said tube nest, thereby to separate condensation from the exhaust gas.
Claim 13
Dependent Claim
28 words
The method of claim 1 wherein said exhaust gas is directed through said tube nest at a velocity within the range of 10 to 60 feet per second.
Claim 14
Dependent Claim
41 words
The method of claim 1 wherein said exhaust gas is passed through a housing containing said nest of tubes, with a pressure drop within the range of 0.2 to 5 inches of water occurring in said exhaust gas within said housing.
Claim 15
Dependent Claim
38 words
The method of 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 16
Dependent Claim
48 words
The method of claim 1 which includes the steps of sensing the outlet temperature of said fluid, and varying the amount of exhaust gas being passed between said tubes of said nest to maintain the temperature of the fluid exiting from said tube nest at a predetermined value.
Claim 17
Dependent Claim
45 words
The method of claim 1 wherein said fluid passed through said 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 18
Dependent Claim
23 words
The method of claim 1 which includes the step of continuously removing water and sulfuric acid which has fallen below said tube nest.
Claim 19
Dependent Claim
20 words
The method of claim 1 which includes the step of directing a spray of liquid onto said nest of tubes.
Claim 20
Dependent Claim
45 words
The method of claim 1 wherein said step of passing said exhaust gas comprises forcing said exhaust gas through a housing in which said tube nest is located, the inside of said housing being covered with a covering to shield said housing from sulfuric acid.
Claim 21
Dependent Claim
60 words
The method of claim 2 which includes the step of passing said exhaust gas through a heat exchanger before passing said exhaust gas to said tube nest, to lower the temperature of said exhaust gas to a temperature which is below the deformation temperature of said coverings on said tubes but above the temperature at which sulfuric acid may condense.
Claim 22
Dependent Claim
37 words
The method of claim 8 which includes the step of directing said exhaust gas in a generally horizontal direction upon exit of said exhaust gas from said tube nest, thereby to separate condensation from said exhaust gas.
Claim 23
Dependent Claim
37 words
The method of claim 10 which includes the step of directing said exhaust gas in a generally vertical direction upon exit of said exhaust gas from said tube nest, thereby to separate condensation from said exhaust gas.
Claim 24
Independent Claim
225 words
The method of recovering heat energy from a hot exhaust gas which initially contains water vapor condensable at a water vapor dewpoint and a corrosive constituent condensable at a temperature above said water vapor dewpoint, and of recovering latent heat while preventing corrosion from condensation of said corrosive constituent, comprising the steps of: passing said exhaust gas in a flow generally perpendicularly to and between tubes of a tube nest having upper and lower groups of tubes; and simultaneously passing a fluid to be heated through successive tubes of said tube nest in counterflow relationship to said gas flow, the amount of said exhaust gas being passed through said tube nest being established in relation to the heat exchange surface area of said tube nest and the input temperature and flow rate of said fluid, and the initial temperature of said fluid being sufficiently below said water vapor dewpoint so that substantial condensation of water vapor continuously occurs, the exterior surfaces of said tube nest being covered with coverings which both shield said tubes from condensed corrosive constituent and provide dropwise condensation of water droplets, so that said droplets may drop from tubes of said upper group through said exhaust gas to tubes of said lower group to wash condensed corrosive constituent from tubes of said lower group, and to dilute the condensed corrosive constituent.
Claim 25
Independent Claim
225 words
The method of recovering heat energy from a hot exhaust gas which initially contains water vapor condensable at a water vapor dewpoint and a corrosive constituent condensable at a temperature above said water vapor dewpoint, and of recovering latent heat while preventing corrosion from condensation of said corrosive constituent, comprising the steps of: passing said exhaust gas in a flow generally perpendicularly to and between tubes of a tube nest having upper and lower groups of tubes; and simultaneously passing a fluid to be heated through successive tubes of said tube nest in counterflow relationship to said gas flow, the amount of said exhaust gas being passed through said tube nest being established in relation to the heat exchange surface area of said tube nest and the input temperature and flow rate of said fluid, and the initial temperature of said fluid being sufficiently below said water vapor dewpoint so that substantial condensation of water vapor continuously occurs, the exterior surfaces of said tube nest being covered with coverings which both shield said tubes from condensed corrosive constituent and provide dropwise condensation of water droplets, so that said droplets may drop from tubes of said upper group through said exhaust gas to tubes of said lower group to wash condensed corrosive constituent from tubes of said lower group, and to dilute the condensed corrosive constituent.
Claim 26
Dependent Claim
42 words
The method of claim 23 wherein said hot exhaust gas initially also contains substantial particulate matter, whereby said droplets of water may entrap portions of said particulate matter as they drop through said exhaust gas to said lower ones of said tubes.
Claim 27
Dependent Claim
35 words
The method of claim 23 wherein said coverings which shield said tubes and provide dropwise condensation of said droplets comprise fluoroplastic coverings having a deformation temperature exceeding the initial temperature of said hot exhaust gas.
Claim 28
Dependent Claim
61 words
The method of claim 23 which includes the step of passing said exhaust gas through a heat exchanger before passing said exhaust gas to said tube nest, to lower the temperature of said exhaust gas to a temperature which is below the deformation temperature of said coverings on said tubes but above the temperature at which said corrosive constituent will condense.
Claim 29
Dependent Claim
12 words
The method of claim 23 wherein said corrosive constituent comprises sulfur trioxide.
Claim 30
Dependent Claim
37 words
The method of claim 23 wherein said exhaust gas comprises the flue gas derived from the combustion of a fuel selected from the group consisting of #2 fuel oil, #4 fuel oil, #6 fuel oil and coal.
Claim 31
Dependent Claim
28 words
The method of claim 23 which includes the step of introducing a scrubbing liquor into said exhaust gas prior to passing said exhaust gas through said tube nest.
Claim 32
Dependent Claim
50 words
The method of claim 23 which includes the steps of monitoring the initial temperature of said exhaust gas, and mixing a cooler gas with said hot exhaust gas to prevent the temperature of the gas passed through the tube nest from reaching or exceeding the deformation temperature of said coverings.
Claim 33
Dependent Claim
84 words
The method of claim 23 wherein said step of passing said exhaust gas comprises forcing said gas substantially downwardly through said tube nest and said step of passing said fluid comprises passing said fluid through upwardly successive tubes of said nest, whereby the fluid in said various of said tubes is warmer than the fluid in said lower ones of said tubes and the fall of said droplets may transfer heat from said various of said tubes to said lower ones of said tubes.
Claim 34
Dependent Claim
38 words
The method of claim 23 which includes the step of varying the amount of said exhaust gas being passed through said tube nest to maintain the temperature of gas exiting from said tube nest at a predetermined value.
Claim 35
Dependent Claim
28 words
The method of claim 23 wherein sufficient condensation occurs that the latent heat of the condensed water vapor exceeds 5% of the total heat transferred to said fluid.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1987-12-11 | 1988-06-11 | 1988-12-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-12-11 | 1992-06-11 | 1992-12-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-12-11 | 1996-06-11 | 1996-12-11 | $7700.00 | Window Closed / Lapsed |