US2195274A - Boiler - Google Patents

Description

March 26, 1940. R. B. FERGUSON 2,195,274

BOILER Filed Dec. 9. 1957 4a) F 9- I 4 5 t Just iji Collector /3 Tl If."

I as INVENTOR f2 5. Ferguson. BY

at? fl M ATTORNEY t a MarIzeI v o I I I I zlgszn ii iiNlTED j: STATES I ATENT "oFFieE to General Chemical Company, New-York,

- N. Y., a corporation-of New York Application'December 9, 1937, Serial n65 178,895

' 5 Claims. (c1.122- 7) This invention relates to boilers and more tween the tubes and shell and consequent failparticularlywaste heat boilers for extraction of we of the boiler parts. The refrac ory n n heat from hot gases formed in industrial proc- I and the tubes restrict the path of flow of the esses. 1 v hot, dusty, corrosive gases so that thegases 5 It is an object of the invention to provide a sweep at relatively high'velocity over the tubes ,5 waste'heat boiler for the efficient extraction of and minimize collection on the tube surfaces of heat from corrosive, dust laden hot gases, in dust layers which would interfere with efficient which hot gases sweep at relatively high velocity transfer of heat from thegases to the liquid in over heat transfer surfaces substantially parallel the tubes. The linin a s protects the c e 10 to the direction of flow of the gases, thereby S O be w e u e d qu r ms, the 10 minimizing collection on the surfaces of dust P s the 501161 most Subject to Corrosion, layers preventing efficient and rapid transfer r m e rec fl cw 0 t e 'h t corrosive e of heat from the gases to the boil r, thus diminishing the tendency of the connec- It is a further object of 'the inventio'n to protions to corrode. I I vide a waste heat boiler for the efiicient extracn t e accompanying drawing, where there is 15 I tion of heat from corrosive, dust laden gases so Shown for purposes of exemplification a preconstructed and designed that in operation a ferred embodiment of theinvention,

minimum of corrosion of the boiler surfaces 1' is a de v i n depicting S w a takes place. diagrammatically the boiler of the invention and v It is a further object of the invention to proapparatus in connection with which it may 'lzo vide a boiler which ,requiresa minimum of floor p oyed,

space, is of rugged construction and economical Fig; 2 is avertical sectional View through the to maintain, and which is not subject to failure boiler, parts being shown in elevation, and due to unequal expansion" of the boiler parts. Fig 3is a partial sectional view along line 3-3; 2 Other objects and advantages will appear-here o ig. 2- I inafter, 1 1 i In the drawing, l designates apparatus for In accordance with the invention, I have proproducing hot, corrosive, dust ladengases, which videdoa waste heat boiler of the liquid tube type may be, for'example, a'shaft furnace for roasting. involvingva refractory lined shell surrounding a .finely divided sulfides, e. g., iron pyrites, copper passageway for flow therethrough of hot, corpyrites, pyrrhotite, zinc blend and flotation con- 3 rosive, dust laden gases, e. g., sulfur dioxide concentrates of the same, while suspended in an oxitaining gases produced by the suspension roastdizing gas, for the production of sulfur dioxide ing in a shaft furnace of finely'divided sulfides, for use in the manufacture of sulfuric acid, the such as iron pyrites, pyrrhotite, flotation con;- paper making industry or other purposes. The

centrates, etc, and equipped in theneighborhot, corrosive, dust laden, sulfur dioxide con-.' hood of its-opposite ends-with liquid drums surtaining gases produced in shaft furnace I may be rounding the passageway and an expansion joint passed through pipe2 downwardly through the located between the drums. The drums are waste heat boiler of this invention designated connected by tubes located'within thelcassagegenerally by reference character 3 where the way and providing heat transfer surfaces for the gases are cooled and steam is generated andthen extraction of heat from the gasesthe major passed through conduit 4 to dust collector 5 or portions of the tubes extending substantially other apparatus. I parallel to the longitudinal axis of the shell, 1. e. Referring more particularly to Figs. 2 and 3, parallel to the direction of flow of gases through the boiler 3 involves a hollow vertical boiler shell the passageway, and theflopposite ends of the Esurrounding gas passageway l andequipped in I tubes being benttoWard-the shell and communithe neighborhood of its upper and lower ends 1 catingwith the liquid drums. The connections with annular water drums 9 and I0 respectively, between thetubes and the drums thus occurs which may be referred to collectively as a liquid outside the main flow of gases through the paschamber. The shell is provided intermediate the sageway. A steam drum is connected to the drums 9 and II! with an expansion joint H. 5

liquid drums by upcomers and downcomers. Drums 9 and I0 communicate with eachother This construction and location of the tubes by means of a series of water tubes I2, the major and the expansion joint compensate for unequal portions of which lie within the passageway 1 expansion and contraction of the waste heat parallel to the directionof flow of gases there- I boiler parts, preventing injurious strains bethrough, i. e. parallel to the longitudinal axis of 55 5 preciated that the connections 13 by downcomers contraction of the tubes and shell and prevent would damage the boiler,

injurious strains which e. g. break the connections betweenthe tubes and the shell, with consequent failure of the boiler.

The portions of the interior between the water drums 9 andglfl are lined with refractory material Hi. This refractory lining forms recesses in the passageway 'l within which are located connections l3 and confines the direct path of flow of the hot, dusty, corrosive gases so that the connections lie without the direct path of gas flow. It will be apbetween tubes l2 and drums 3, lil, if subjected to the direct flow of corrosive gases such as sulfur dioxide containing gases, would deteriorate more rapidly due to corrosion than the tube surfaces. The refractory lining not only protects the interior of the boiler shell against corrosion by the gases, but owing to the location of the connections [3 within recessesformed by the lining, protects these connections from the direct flow of the gases thereby minimizing corrosion of the connections.

Refractory limng i5 and tubes I? restrict the portion of passageway I in which the parallel portions of the tubes are located so that the hot gases sweep over these portions of the tubes at a ,higher velocity than through the remainder of the passageway. The high velocity of the gases and the parallel relation of the tubes to the direction of flow of the gases minimizes collection on the heat transfer surfaces of thetubes of dust layers which would impede transfer of heat from the hot gases to the liquid in the boiler and impair the eiiiciency of the boiler. The boiler shell may be provided with hand holes H to permit access to the interior of the drums'Q, iB'for purposes such as cleaning tubes- I2. The exterior surface of the shell is covered with heat insulation 2!. Valved outlets i9, 20

may also be provided for draining the drums and removing sediment therefrom.-

Steam drum '22 is connected to water drum Ill 2 1 and to water drum 9 by upcomers 26. comers and tubes l2 provide a circuit for flow of water through the steam drum, water drums and tubes. Reference numeral 3i] designates a connection between the top of water drum 9 and the steam drum to prevent steam from accumulating in the upper portion of water drum 9 and reference numeral 32 designates a water gauge on the steam drum. The steam drum is equipped with. a steam outlet 34.

The lower end of the boiler shell forms dust collecting chamber 38 into which dust settles from the gases passing through the boiler to outlet in. Reference numeral M designates a closure for the dust collecting chamber which may be opened periodically for removal of dust.

The cooled gases passing from the boiler through outlet 40 may be conducted to a dust collector} for removal of the remainder of the of the boiler shell, adjacent the point of entry of the hot gases and The steam drum, upcomers, downr dust and thereafter utilized for any desired purpose, e. g. sulfur dioxide containing gases may be employed in the manufacture of sulfuric acid or paper. Due to the reduction of the temperature of the gases in the boiler below that at which sulfur dioxide corrodes ordinary sheet iron or steel, with consequent reduction of the volume of the gases, the dust collector 5 may be of relatively inexpensive metal construction and small size as compared with the large, refractory dust chambers employed where the sulfur dioxide containing gases are passed directly from the shaft furnace into the dust collecting chamber.

Accordingly, it will be seen the boiler of this invention is economical. to maintain and is not subject to failure due to unequal expansion of the boiler parts. The portions of the boiler most subject to deterioration by the corrosive action of gases, such as hot sulfur dioxide containing gases from a shaft furnace, are protected from the direct flow of the gases, thereby minimizing corrosionof the'boiler parts. Thetubes forming the heat transfer. surfaces of the boiler are parallel to the flow of gases and the gas passage in which the tubes are located is restricted so the gases flow through the remainder of the boiler, thereby minimizing collection of dust on the tubes and promoting continuously efficient extraction of heat from the gases.

Since certain changes may be made in the above construction'without departing from the scope of the invention,'e. g. the hot gases may be passed upwardly instead of downwardly through the boiler, it is intended the above description shall be interpreted as illustrative and not in a limiting sense.

What is claimed is:

l. A waste heat boiler comprising in combination a boiler shell providing a passage for flow of hot gases therethrough and spaced liquid chambers, a plurality of tubes within said passageway, portions'of said tubes intermediate the ends thereof being substantially parallel to the direction of gas flow-through said passageway, the end portions ,of said tubes being bent outwardly and communicating with said liquid chambers, a refractory lining covering the portion of said shell between said chambers but not the portions of'said chambers with which said tubes are connected so that hot gasespassing through said shell contact said chambers and the entireexterior surfaces of said tubes, said lining restricting the portion of said'passageway within which the parallel portions of said tubes are located whereby said restricted portion is of smaller cross sectional area than the unlined portions of said shell and hot gases pass over the parallel portions of saidtubes atgreater velocity than through the unlined portions of said boiler.

2. A waste heat boiler for extracting heat from hot dusty gases from industrial processes comprising in combination an. upright boiler shell of substantially uniform cross sectional area providing a passageway for flow of hot gases therethrough in one direction only and spaced liquid drums surrounding said passageway, a plurality of tubes having portionsintermediate the ends thereof extending substantially parallel to the direction of gas flow through said passageway, the end portions of said tubes being bent outwardly and connected with said liquid drums, the parallel portions of said tubes being spaced from eachother and from saidshell, a

refractory lining covering the portion of the entire exterior surfaces of said tubes, said refractory lining restricting the portion of said esses comprising in combination a vertical boilviding a passageway for flow passageway in which the hot gases 7 parallel portions of said tubes so that thegases sweep over the parallel portions or the tubes at greater velocity than through the unlined portions of the shell, said lining protecting the connections between said tubes and said liquid drums from the direct flow of hot gases, a steam drum, and upcomers and downcomers locatedexteriorlylof said shell and connecting saidsteam drum to said liquid drums. T

3. A waste heat boiler for hot, dusty, corrosive gases from industrial procer shell of substantially uniform cross sectional area providing, a top inlet, a bottom side outlet and a passageway for flow of hot gases only in the downward direction therethrough, spaced water drums surrounding said shell, aplurality of tubes within said passageway, portions of said tubes intermediate the ends thereof being substantially parallel to the direction of gas flow throughsaid passageway, the end portions of said tubes being bent outwar ly and communicating with said water drums, a refractory lining covering the portion of said shell between said water drums'whereby the por--' tion of said passageway in which the parallel portions of said tubes are located is of smaller cross sectional area than the portions of the passageway above and below said lining so that hot gases flow over the parallel portions of said tubes at greater velocity than through the portionslof said shell above and below said lining and deposition of dust from said gasesonto said tubes is minimized,said dust chamber catching dust settling from said gases owing to the reduction of velocity and change of direction thereof in'the lower portion of said boiler shell, a steam drum and upcomers and downcomers located exteriorly of said shellconnecting said steam drum to said water drums.

4. A waste heat boiler for extracting heat from hot dusty gases from industrial processes comprising in combination a'hollow boiler shell proof hot gases in only .one direction therethlrough, drums surrounding said shell at locations spaced longitudinally thereof and cooperating with the shell to form water spaces,a plurality of spaced water tubes within said passageway, the intermediate major portions of said tubes being substantially. parallel to the direction of thegas flow through said passageway, the end portions of said tubes being bent outwardly, and communicating through said shell with said water said drums connected to contact the extracting heat from passageway, a, 'dust chamber located at ,the lower end of said and below over the parallel portions of said tubes at great- ,'between the upper ends spacespa refractory lining of substantial thickness covering the portion of the interior of said shell in' which the parallel portions of said tubes are locatedwhereby the portion of said passageing circumferentially therearound at a location between said drums, said expansion joint and the bent construction of said tubes compensating for unequal expansion of said shell and tubes owing to temperature changes.

5. A waste heat boiler forextracting heat from hot, dusty, corrosive gases from industrial processes comprising in combination a vertical cylindrical boiler portions of the passageway shell of substantially uniform cross'sectional area providing a top inlet, a bot-- tom side outlet and a passageway for flow of hot gases only in the downward direction therethrough, cylindrical drums surrounding xfsaid shell and forming therewith; water spaces extending circumferentially around the shell, a

plurality of spaced water tubes Within said passageway, thema'jor portions of said tubes intermediate the ends thereof being substantially parallel to the direction of gas flow passageway, the end portions of said tubes being bent outwardly and communicatingthrough said shell with said water. spaces, a refractory lining coveringthez'portion of said shell between said through saidwater,spaceswherebythe portion of said pas- V sagewayin which the parallel portions of said tubes are area than a said lining so that the hot gases flow er velocity than through the portions of said shell above and below saidlining and deposition of dust from said gases onto said tubes is inhibited, a refractory lining covering the upper end portion of the'interior of .said shell, said linings providing a recess within which the connections of said tubes and said shell are located thereby protecting said con nections from the direct flow of the hot corrosivev gases without preventingheat'exchange between the gases and liquid in shell, a dust chamber in shell, an expansion joint extending circumferentiallyaround said shell intermediate said drums, the bent ends of said-tubes and said expansion joint compensating for unequal expansion and contraction of said boiler longitudinally of said shell, asteamfldruin, and upcome rs and downcomers located exteriorly of said shell connecting said steam drum to said water spaces.

said drums through "the ROBERT BRUEN FERGUSON.

the lower portion of thev located is of smaller cross sectional the portions of the passageway'above'

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