US2856906A - Boiler - Google Patents

Description

Oct. 21, 19 w. H. ARMACOST 2,855,905

' BOILER Filed Nov. 15, 1954 4 Sheets-Sheet 1 g I INVENTOR.

Wilbur H. Armucost A TTORNE 1 cfi. 23, W5 w. H. ARMACOST 2,856,906

BOILER Filed Nov. 15, 1954 4 Sheets-Sheet 2 Wilbur H. Armucost [NI E NTO R.

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B1, ['M A! JTTORNEY w. H. ARMAcoST BOILER 4 Sheets-Sheet 3 Filed Nov. 15, 1954 INVENTOR.

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51 (an A! {W ATTORNEY BOILER Wilbur H. Armacost, Scarsdale, N; Y., assignor to Combustion Engineering, Inc., New York, N. Y., a corporation of Delaware Application November 15, 1954, Serial No. 468,826

3 Claims. (Cl. 122-478) This invention relates :to high capacity steam generators or boilers of the utility type and particularlyto such boilers wherein steam temperature is controlled by varying the zone of combustion longitudinally within the water walled furnace.

The invention, in general, comprises a steam generating unit made up of two identical boilers positioned in side by side relation and having a common steam and water drum as well as a common stack with the unit being arranged in a compact and highly efficient manner to provide for efficient operation at a minimum of cost. Each of the boilers is itself compact y arranged so as to reduce cost to a minimum and provide a boiler having a low center of gravity as compared with the present day high capacity utility type boilers making the same particularly well adapted for hurricane and earthquake areas. These boilers include an upright elongated furnace having its sole exit for combustion gases adjacent-the bottom and fired by suitable burners mounted in the ,upper portion of the furnace walls but spaced from .the top thereof and adjustable in such a manner that the zone of combustion may be varied longitudinally of the furnace. The walls of the furnace as well as .the roof are lined with vertically disposed steam generating tubes with adjacent tubes being welded together throughout their length to form a rigid substantially fluid tight wall structure. The steam and water drum of the boilers-is positioned substantially intermediate the upperand lowerends of thefurnacc and is in communication with the inlet and outlet .of the steam generating tubes in the usual manner with pumps being provided to establish a forced circulation of the boiler water from this drum through the steam generating tubes. Extending from the combustion gas exit of the furnace is a generally horizontal gas pass which houses reheater elements and which leads to a vertical gas pass extending upwardly therefrom and which houses the superheater elements of the boiler. Positioned'directly over the horizontal gas pass and intermediate the furnace and the vertical gas pass is the airheater .of the boiler which is of such a size relative to the length of the horizontal gas pass that it occupies substantially the entire space intermediate the vertical gas pass and the furnace. Each of the boilers is supported by means of a structural steel framework the uppermost portion of which lies substantially below the upper end of the furnace but above the center of gravity of the furnace. At this elevation-the furnace is interconnected with the support structure in such-ama-nner that the furnace is suspended therefrom.

It is the object of this invention to provide an efficient and economical steam generating unit wherein the boilers are extremely compact and have alow center of gravity and wherein an increase in the control effect obtained by varying the combustion zone longitudinally within the water walled furnace of the boiler is achieved.

"Other and further objects of the invention will become apparent to those skilled in theart as the description proceeds.

' 2,856,906 Patented on. 21, 1958 With the aforementioned objects in view, the invention comprisesan arrangement, construction andcombin'a'tion of the elementsofthe boiler in :such a manner as to attain the results desired as hereinafter more particularly set forth in the following detailed description of an illustrative embodiment, said embodiment being shown by the accompanying drawing wherein:

Figure 'l is a vertical section of the steam generating unit of the present invention taken generally along line 1*1 of Fig. v2 and showing the two boilers in side by side relation;

'Figure '2 is a vertical section of this generating unit taken along line 2-4. of Fig. land showing the layout of each boiler;

Figure 3 is a horizontal sectional view of the steam generating unit taken generally along line 3--'3-of Fig. '2;

Figure 4 is a horizontal sectional View through one of the furnaces of the steam generating unit at thelocation of the burners, taken generally along line 4+4 of Fig. 2, and showing the disposition of the burners in the furnace;

Figure 5 is a longitudinal sectional view through one of the burner units taken generally along line 5--5 of Fig. 4;

Figure 6 is a fragmentary detailed view of the water wall which forms the inner surface of the furnace;

Figure 7 is a transverse sectional view taken along line 7-7 of Fig. 6.

Referring now to the drawings wherein like reference characters are used throughout to designate like elements the steam generating unit depicted therein comprises two identical boilers 10 and 12' positioned in closely spaced side. by side relation. Each of these boilers includes an elongated upright furnace 14 tangentially fired by means of burner units-16 and having its sole exit for combustion gases, identified as 18, located-in the-lower portion thereof. The walls of furnace 14 are lined with vertically extending steam generating tubes 20 which are positioned in tubes 20 that line the remaining two walls of the furnace are also interconnected with header 24 which is in turn connected with steam and water drum 26 through conduits 25, this drum being a common drum for both boilers of the steam generating unit and being positioned substantially midway between the vertical extremities of the furnaces of these boilers. Depending from steam and water drum-26are downcomers 28 connected to the inlet of pumps 30 which are effective to force boiler water through conduits 32 and into orifice drum 34 from which it is distributed to steam generating tubes 20 which have their lower or inlet ends connected into drum 34.

In order that the flow through each of the tubes 20 will be regulated so as to obtain maximum efficiency each of these tubes is provided at its inlet with a flow'restrictor (not shown) of preselected size as is well known in-the controlled circulation type of boiler. As the boiler water is forced upward through tubes 20 a portion of this water is converted to steam with the thus producedsteafm and water mixture entering header 24 and then passing;

Extending laterally from furnace exit 18 is horizontal gas pass 36 which leads. to and is interconnected withupwardly extending gas pass 38 Within these gas/passes are positioned the steam heating elements of the boiler with gas pass 36 having reheater 40 disposed therein which receives steam through conduit 42 after a portion of its energy has been utilized and reheats the same to a desired temperature and pressure while gas pass 38 has superheater 44 positioned therein and interconnected with steam and water drum 26 by conduit 46 so as to receive saturated steam therefrom, which, after passing 1 is positioned a substantial distance below the upper end of furnace 14 and directly above horizontal gas pass 36 which is of such a length as to permit the airheater to be snugly positioned between gas pass 38 and furnace 14.

Intermediate the airheaters of the two boilers is a common stack 54 which is interconnected with each of the airheaters by means of suitable ducts to receive the I,

combustion gases as they pass therethrough and convey these spent gases to waste.

The entire steam generating unit is supported from a structural steel framework made up of I beams 56 arranged and interconnected in the usual manner to form a sturdy supporting structure. This supporting framework extends only slightly above steam and water drum 26 to an elevation which is above the center of gravity of furnace 14 but well below the upper end of the furnace and at which elevation the furnace is interconnected with the supporting framework in such a manner as to be hung therefrom so that the portion of the furnace located below this elevation expands downwardly while the portion located above this elevation expands upwardly as the temperature of the water walls increase.

The furnace 14 is tangentially fired and for this purpose burner units 16 are mounted in the furnace walls at the four corners of the furnace. Fuel, which may be of any desired kind such as pulverized coal, oil, or the like, is supplied to these burner units through conduits 58 with combustion supported air being forced through air heater 50 by blower 60 and introduced into the burner units from wind box 62 to which it is conveyed by means of duct 64.

Each of the burner units comprises a number of vertically arranged nozzles 66, three such nozzles being shown (Fig. 5), with these nozzles being pivotally mounted around horizontal axes and suitable operating mechanism such as linkages 68 being provided to control the pivotal movements of these nozzles and thereby vertically adjust or regulate the disposition ofthe zone of combustion in the furnace for the purpose of controlling superheat or reheat temperature in a well known manner.

In the boilers of the present invention this type of superheat and/ or reheat control is of increased effectiveness in contrast with that which has heretofore been obtained. This increased effectiveness is due to incorporating this type of control in a furnace which has a completely water cooled roof and is fired adjacent its upper end with the sole exit for combustion gases being at its lower end. With this novel combination the roof tubes, which correspond to the floor tubes in the organizations heretofore having this control, will remain free of falling ash deposits and other foreign matter and therefore they will have a much higher heat exchange rate than the corresponding floor tubes in prior art organization which will become coated with this matter which will of course act as a heat insulatorto a great degree.

This effect will of course be most pronounced with pulverized coalfiring where ash and foreign matter accumulation will be the greatest and when, employing this fuel the bottom of the furnace of the illustrative organi zation will be constructed for and provided with means to remove slag therefrom. When the nozzles 66 are tilted to the extreme position where the zone of combustion is at its most remote position from exit 18 the combustion zone will be located immediately below the roof tubes which remain clean and in excellent heat absorbing condition. The result of this is to substantially increase the heat absorption in the furnace over that heretofore obtained when the burner nozzles are so tilted thereby correspondingly further reducing the temperature of the gases exiting from the furnace and thereby further lowering the steam temperature. This improved operational elfect is not obtained with prior art organizations which either have the combustion gas exit at the top or do not employ roof tubes with this type of super heat control. In these boiler organizations which have the combustion gas exit at the upper end ash and other matter fall to the bottom of the furnace and collect so as to form a layer over the tubes which line the floor thereby greatly decreasing the heat transfer effectiveness of these tubes whereby the control effect obtained by tilting the burners to move the zone of combustion to its most remote position from the furnace outlet is substantially impaired.

With the controlled circulation boilers of this invention wherein the entire supporting structure as well as the steam and water drum are located a substantial distance below the upper end of the furnace and where the gas passes are located relatively close to the ground the center of gravity of the entire boiler is extremely low making such a boiler highly desirable in locations where hurricanes and/or earthquakes are prevalent. Moreover this low center of gravity together with the extremely compact arrangement of the boilers and the entire unit results in a substantial reduction in cost. By means of the welded water wall construction the furnace is extremely rigid enabling it to be suspended from a point intermediate its extremities with a substantial portion of the furnace projecting above this point of support without any substantial additional support being required for this upwardly extending portion.

While I have illustrated and described a preferred embodiment of my novel boiler organization it is to be understood that such is merely illustrative and not restrictive and that variations and modifications may be made therein without departing from the spirit and scope of the invention. I therefore do not wish to be limited to the precise details set forth but desire to avail myself of such changes as fall within the purview of my invention.

What I claim is:

l. A controlled circulation boiler comprising an upright elongated furnace fired in its upper region at a location spaced somewhat below the roof of the furnace and having its sole exit for combustion gases at its lower end, a steam generating circuit including longitudinally extending tubes lining the furnace walls and roof, pump means for establishing a forced circulation therethrough and a steam and water drum supported a substantial distance below' the furnaces upper end, burner means at said location for injecting fuel into said furnace, said burner means being mounted for pivotal movement about a generally horizontal axis, means controllab-ly directing said burner means to vertically adjust the zone of combustion within the furnace to control within limits the temperature of the gases leaving the furnace, a generally horizontal gas pass extending laterally from said combustion gas exit and having steam heating heat exchange elements disposed therein operatively connected to receive and heat the steam generated in said circuit, a support framework for supporting said boiler and disposed about said furnace, said framework terminating at a height adjacent said drum and substantially below the upper end of said furnace and being effective to directly support said drum, said support framework being interconnected with the furnace walls at said height and in a manner so that the furnace is suspended therefrom.

2. A controlled circulation boiler comprising an upright elongated furnace fired in its upper region at a location spaced somewhat below the roof of the furnace and having its sole exit for combustion gases at its lower end, a steam generating circuit including longitudinally extending tubes lining the furnace walls and roof and disposed in side by side relation with adjacent tubes being welded together throughout their length, pump means for establishing a forced circulation therethrough and a steam and water drum supported a substantial distance below the furnaces upper end, burner means at said location for injecting fuel into said furnace, said burner means being mounted for pivotal movement about a generally horizontal axis, means controllably directing said burner means to vertically adjust the zone of combustion within the furnace to control within limits the temperature of the gases leaving the furnace, a generally horizontal gas pass extending laterally from said combustion gas exit and having steam heating heat exchange elements disposed therein operatively connected to receive and heat the steam generated in said circuit, a vertical gas pass extending upwardly from the exit and of said horizontal gas pass to an elevation substantially below that of the upper end of the furnace and also having heat exchange elements disposed therein including steam heating elements operatively connected to receive and heat steam generated in said circuit, a rotary regenerative air heater means disposed immediately over said horizontal gas pass and intermediate said vertical gas pass and said furnace and located a substantial distance below the upper end of the furnace, said air heater being connected with the outlet of said vertical gas pass to receive combustion gases therefrom and connected with said furnace to supply preheated air thereto, the length of said horizontal gas pass being such as to permit said airheater to be compactly positioned between said vertical gas pass and said furnace, a support framework for supporting said boiler and disposed about said furnace, said framework terminating at a height adjacent said drum and sub stantially below the upper end of said furnace and being effective to directly support said drum, said support framework being interconnected with said boiler at said height and in a manner so that the furnace is suspended therefrom.

3. A steam generating installation of the controlled circulation type comprising two parallel side by side slightly spaced upright furnaces fired in their upper region at a location spaced somewhat below their roofs and having their sole exit for combustion gases adjacent their lower end, each of' said furnaces being of rectangular transverse section and having longitudinally extending steam generating tubes lining their walls and roofs, a

6 common steam and water drum with which said tubes communicate and which is disposed a substantial distance below the furnaces upper end at approximately the midpoint of the furnace, pump means communicating with said drum and said tubes and effective to force boiler water through said tubes, burner means mounted in the vertical walls of each furnace at said location for injecting fuel into said furnaces, said burner means being mounted for pivotal movement about a generally horizontal axis, means controllably directing said burner means to vertically adjust the zone of combustion within the furnaces to control within limits the temperature of the gases leaving the furnaces, a supporting framework disposed about said furnaces to a height above the center of gravity thereof but substantially below the upper end thereof and interconnected with the furnace thereat and in a manner so that the furnace is suspended therefrom, means supporting said drum directly from said support framework, two parallel generally horizontal gas passes one extending from the exit of each furnace, two generally vertical parallel gas passes one extending upwardly from the exit end of each of the horizontal gas passes to a height substantially below the top of the furnace, heat exchange elements disposed in these gas passes operative to receive and heat the steam generated in said steam generating tubes, a rotary regenerative air heater means positioned directly over one of the horizontal gas passes at an elevation substantially below the top of the furnace and communicating with the outlet of the vertical gas pass associated with said one horizontal gas pass, a second rotary regenerative air heater means positioned directly over the other horizontal gas pass at an elevation substantially below the top of the furnace and communicating with the outlet of the vertical gas pass, the length of each horizontal gas pass being but slightly greater than that of the horizontal dimension of the air heater means disposed thereabove, and a stack intermediate said air heaters and in communication therewith to receive combustion gases therefrom.

References Cited in the file of this patent UNITED STATES PATENTS 1,860,364 LaMont May 31, 1932 2,003,419 Artsay June 4, 1935 2,312,375 Whitney, Jr. Mar. 2, 1943 2,320,911 Cooper June 1, 1943 2,325,384 Emmet July 27, 1943 2,418,815 Baver Apr. 15, 1947 2,583,599 Schoessow Jan. 29, 1952 2,697,420 Lloyd Dec. 21, I954 FOREIGN PATENTS 682,121 Great Britain Nov. 5, 1952 693,029 Great Britain June 17, 1953

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