US2201623A - Process for producing steam - Google Patents

Description

May 2,1, 194.0. W, D, LA MQNT l 2,201,623 i PRbcEss FOR PRoDUcING STEAM' Original Filed Oct. 5, 1955 2 Sheets-Sheet 1 las l @Non I BY A'rroRNEY 17 INVENTO oa May 21 1940 W. D. LA MONT 2,201,623

:PROCESS FOR PRODUCING STEAM i original Filed oct. 5, 193s 2 sheets-'sheet 2 611ix ,Z9 'I9 INVENTOR.

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Patented May 21, 1940 PATENT OFFICE PROCESS FOB. PRODUCING STEAM Walter Douglas La Mont, North Colebrook, Conn., assignor to W. D. La Mont Inc., Wilmington, Del., a corporation of Delaware Original application October 5, 1933, Serial No.

692,236. Divided and this application December 25, 1934, Serial No. 759,130 f s claims. (ol. 122-235) This invention relates to high speed steam producing methods.

It deals with supercharger steam boilers and high speed, light weight, power plants using such a boiler, especially a boiler burning fluid fuels, in which all fluids; namely, the fuel, the air (for supporting combustion), and the main worling uid in the tubes of the boiler, each flow at extremely high velocities in the performance of their several duties.

It further concerns the coordination at all speeds, of the velocities of all flowing fluids, to insure the maximum and constant evaporation of the main working fluid in a minimum period of time. This application is a divisional of my Serial No. 692,236.

The method of steam generation in accordance with the present invention makes possible semiunidirectionalilow of the main Working fluid in my steam generating elements under conditions of high temperature radiant and convection heat transfer at high rates of heat release.

A main object of my invention is to reduce the size, weight, and cost of high speed steam producing apparatus and high speed steam power plants. I do this by increasing their speed of operation, the detailed means and methods of which are in this oase.

By my improved methods of operating steam boilers, I insure their continued performance under long sustained overload conditions through many years of life up to the limit of the maximum heat load conditions for which they are designed, without destroying the boiler, practically regardless of how rapidly combustion temperatures or load conditions may change, or how fast uids in all my boiler high speed uid streams may liow with my improved methods of supercharging and coordinating their various velocities.

It is vital that the main working fluid especially, flow at least semi-unidirectionally at all times, under al1 steam making loads and speeds. substantially regardless of iirebox temperatures or rates of heat release.

The improved method of steam generation in accordance with the present invention is attainable by virtue of the following features: a positive and controlled supply of water to each of the steam generating tubes or elements conveying working fluid through the water wall surrounding the combustion zone; and through the steam making elements exposed to convection heat to provide steady and continuous circulation of the water through the water passages or tubes of the Water Wall or water wall boiler; and steam generating elements exposed to convection heat to provide for the proper and adequate flow of water through the dilerent parts of the steam generating apparatus and in such relation to the steam generated in said parts or to the condition of the steam generated therein that an adequate flow of Water may be maintained through each part and in suitable relation in one part relative to the other. It is a still, further object of the invention to provide for the positive control of the amount of water delivered to or flowing through the different parts and to control the conditions under which it flows vso as to accomplish the proper delivery to and flow through the different parts of the steam generating apparatus to suit conditions of steam generation in said parts.

A still further object of the present invention,

is to increase the amount of water circulatedand therefore the speed of the circulation of steam and water in the tube with the increase in the rate of heat release, in order to increase the rate of heat transfer from the metal of the tubes to i the Water and the steam by moving the formlng bubbles of steam away from their point of formation faster, thus protecting the water wall tubes especially, and the other tubes of the boiler from the increasing heat to which they are exposed with every increase in the rate of heat release in the combustion chamber.

An important object of this invention is to disclose how so-called full water wall tubes can be operated with positive input of water into each tube in suiiicient quantity to protect each tube regardless of how rapid rates of heat release are obtained in the combustion chamber, up to the maximum heat effects for which it is designed to withstand; and to show and describe how semiunidirectional flow of steam and water within and throughout a portion of the length of the tube can also always be uniformly obtained under any combustion chamber heat releasing condition for which it is designed.

A `prime object of the present invention is to increase the speed of steam generation and power production, thus making my steam generating apparatus and my steam power plant smaller, lighter weight, and less expensive.

This present invention is particularly concerned with the improvement of high speed steam boilers, and power plants embodying the same, and methods of operating said boilers and said power plants. Where my invention, and/or any of its features. applies to flash boilers and to high speed power plants using said flash boilers. such improvements are well within the scope of my invention as herein described.

While my invention has been described herein as relating to steam generating apparatus is intended especially for the generation of steam from water, it will be understood that the terms steam and water as uSed in the specifications and claims are intended to include as equivalents, and liquids which might be handled by the novel process and/or apparatus herein described, resulting in the generation of any vapors which might be handled by or be useful in connection with my process and/or apparatus, and it will also be understood that many of the novel {eatures of this invention are applicable in other fields than that for which the apparatus herein specifically illustrated and described is particularly intended.

An important object of this invention is to coordinate the quantity of liquid used in forced circulation with pressure drop devices in the steam generating tubes in order to obtain positive input of water into each tube in suillcient quantity to protect each tube regardless of how rapid rates of heat release are obtained in the combustion chamber, up to the vmaximum heat effects for which said (combustion chamber) is designed to.

withstand; and to show and describe how the flow of steam and water within and throughout.

the length of the tubes can also always be semiunidirectionally uniform under any combustion chamber heat releasing conditions for which they are designed.

- Since this invention is concerned directly with steam making apparatus for producing steam rapidly, and with methods of operating such apparatus using high speed equipment for the production of power, the separate and correlated inter-actingmechanical features and combinations by which all of these above objects are attained, and their close inter-relation and interdependence in securing high speeds in steam generation, and steam power production, (which are among the mainl objects of this invention), are made possible, in certain instances, by the creation of new devices and methods of making and using said devices.

Other objects and features will be particularly pointed outl and disclosed hereinafter in the illustrations, descriptions, specifications and claims of this present patent application.

In the drawings:

Fig. 1 is a complete view of' a power plant operating in accordance with certain modifications of my invention.

Fig. 2 is a section taken along the lines A--A of my high speed steam boiler shown in Fig. 1;

Fig. 3 is one method of placing an orifice or pressure drop device in lmy working fluid heating element;

Fig. 4 is a view partially in elevation and partially in section of one of my preferred forms of one of my working fluid steam generating waterwall elements .attached to its intake manifold and its outlet manifold as shown in Fig. 1 in accordance with my present invention;

Fig. 5 is a diagrammatic view of a down iiow tubular Water wall in a radiant heat releasing firebox or combustion zone made in accordance with my invention and wherein the fuel air mixture and the burned gases travel practically parallel to the Water flowing in the Water wall tubes;

Fig. 6 is similar to Fig. 5 the difference between the two gures being that here the fuel gases.

unburned and burned. travel in counter-current relation to the high velocity flow of themain working uid in the water wall tubes;

Fig. '7 ilustrates a. coil type of water wall diagrammatically the coils leading the water upward, the ilow of unburned and burned gases also being upward; the circulating pump preferably hasa separate wheel for each steam generating tube to discharge water directly and only to the tube connected to it;

Fig. 8 is a similar diagrammatic view of that in Fig. 7 wherein the coils forming a water wall or a liquid wall of working iiuid around the iirebox or combustion chamber lead the water upward while the unburned and burned gases flow countercurrent or downwardly; the circulating pump preferably here again having a. separate wheel (or plunger, if a reciprocating pump is used) for each tube, to discharge directly into and maintain hydraulic pressure inside of each water tube;

Fig. 9 is a complete power plant showing the direction, the various fluids flow in their respective paths through my boiler and the close interrelation between the action of the boiler and my high speed power plant asa whole of which my boiler forms a part;

Fig. 10 is a plan view of one of my fluid heat absorbing elements, with its pressure drop device as shown in position in Fig. 9 at point A.

In Figure 1 of the drawings is shown a power .plant including, as a part thereof, a steam generator adapted to produce steam of high energy content, in accordance with the present invention. The steam generator is designated by I having a plurality of steam generator water wall tubes 34 therein receiving water from the water wall inlet header 33, and discharging water and/or steam to the steam generator outlet water wall collecting header 36. 'I'hese tubes are exposed to a source of radiant heat produced by a flame fed with fuel from burner 2 in the burner throat 3. The combustion of the fuel oil is assisted by a source of air which may be supplied from the super-charger 6, to which air is admitted through inlet Il, feeding air through the discharge lead 4 to the burner throat. The steam generator tubes are shown fltted with pressure drop devices 35. for controlling the input of water into each tube in sufficient quantity to protect the tube and to control the iiow of steam and water in each tube to insure the proper` operation thereof, said pressure drop devices being placed in an intermediate portion of the length of each tube, in accordance with the present invention. These devices are shown in greater detail in Figures 3 and 4.

In accordance with my invention. the placing of pressure drop devices beyond the water inlet end of the tubes, or in that part of the tube exposed to radiant and/or convection heat. is a preferred posi-tion for these pressure drop devices, or orifices, if orifices are used as pressure drop devices. l

Also, in accordance with my invention, the pressure drop devices are placed preferably at any point in the tube beyond the point where steam begins to form, at the designed rate of heat release for' the steam generator, thus insuring under the proper load conditions, the passing through the pressure drop device of atleast some steam with the water.

This immediately gives, the advantage of a larger area for steam and water passage through the pressure drop device for a given pressure drop. and a given quantity of water. than would be possible if water alone were passed through the pressure drop device.

This new position of my pressure drop device is also of immediate advantage to reduce the possibility of clogging, whether the steam generator is used, as in my present invention, operating a pa rt of the steam generating tube With a so-called full tube condition, or if the heat release permits, and it is desirable to operate a part of the steam generator under conditions of my previous inventions using less than enough water than is normally required to fill the tube.

However, the most desirable position of my pressure drop device is at that position of the length of the tube which at the maximum rates of heat release for which it is designed will insure a sufficient length of the tube to give unidirectional flow of the working uid so that the steam generator operating as a whole will not have serious steam and water surging conditions caused by that part of the tube in which unidirectional flow is not insured.

By advancing the orifice toward the outlet end of the tube, as in the present invention, the proportion of the length of the tube behind the orifice which has a compact column of steam and water, increases; and the proportion of length past the orifice toward the outlet end, which is subject lto the surging action, decreases; reducing the degree of interference to proper steam making operation from back and forth flow or surging ow. The tube under this condition has an assured unidirectional ow for that part of its length between the orifice vand the inlet end, while the part of the length from the orice to the outlet end may have some degree of surging or non-unidirectional flow. This results in the tubeas a whole giving what is termed semi-unidirectional flOW:

As the rate of heat release increases, the need of advancing the orice along the tube, toward the outlet end of the tube, likewise increases, until the exit end of the tube is finally reached. This is further discussed in my co-pending application Serial No. 686,268.

The selection of the point along the length of the tube where the orice can best be usedl is a matter of the general duty for whichy the apparatus is designed and for which it is to be put in use. The main factors to be considered are- 1. The rate of heat release in the combustion zone.

2. The degree of fluid compactness required to prevent surging in the hydraulic column from behind the orifice to the inlet end of the steam generating tube.

3. The degree of fluid compactness required to prevent surging in the hydraulic column from immediately beyond the orifice to the outlet end of the steam generating tube, in which some surging can be permitted Without interfering with the proper steam making operation of the boiler.

4. The amount of water most desirable for circulation.

5. The degree of pressure drop required to insure one path ow and/or semi-unidirectional flow of the working uid.

Vand pipe I3 is the outlet pipe therefor.

In one of its aspects my invention is a high speed steam generator whose water walls in the radiant heat releasing and receiving area, namely the combustion zone, and whole steam generating tubes exposed to convection heat transfer in the convection heat zone, will not give an undue amount of surging of steam and water travelling back and forth in the tubes but will have positive semi-unidirectional flow of water in each wall tube, at all times, regardless of combustion conditions in the rebox or the size or movement of large steam bubbles shifting from side to side in individual water wall tubes, or group of water Wall tubes, up tothe maximum rate of combustion at which the steam boiler is designed to operate.

In the further aspect, my invention seeks to take this steam made at high speeds, then by means of a high speed steam engine, (preferably a steam turbine operating under high tempera- STO tures and pressures), convert this steam into power in a rapidly operating steam power plant where all auxiliaries are functioning at maximum speeds, and are closely coordinated and controlled to produce power in large quantities With the minimum in size, weight and cost of power producing equipment.

The steam and water collected in header 35 discharges by way of conduits 3`I (Figure 2) into Water level cylinder 8 for maintaining a water level in the System, furnishing reserve power, and insuring water supply to the circulating pumps. The steam is separated from the water in the cylinder 8, and passes through the main high pressure steam line 9, having main control valve 6I therein for controlling the steam to the main turbine I8. Furthermore, a pipe line 1 extends from the upper end of cylinder 8 to auxiliary steam turbine 6 having control valve 42 therein for controlling the drive of auxiliary turbine 6, which drives the air super-charger fan 5, fuel oil pump 21, boiler feed pump I'I and boiler circulat ing pump 26.l

The main exhaust lead I8ik from the main turbine extends from the latter to the main condenser II. Pipe I2 represents the inlet for circulating cooling water to the main condenser II, Pipe I4 is the condensate water discharge from the main condenser II to the main feed tank I5 having feed water inlet 46 and control valve 43 therefor. Vent 41 is associated with the feed water tank, and suction lead 29 extends from the latter to the condensate pump I6 or feed pump I1. I8 is a discharge pipe connecting feed pump I 1 with the water level cylinder 8; I9A is a by pass line for bypassing feed water around the feed pump I1 through water level regulator valve I 9, for controlling the water level in the system; and 20 is a feed stop and check valve on the feed pump discharge lead I8 for stopping and checking the feed of water into the system,

Associated with the cylinder 8 is a safety valve 2I for the boiler at the top of the cylinder, and a blow-orf valve 22 at the bottom thereof. I'he cylinder has a gauge glass 23, and an automatic wate level regulator 24A from which extends a pipe 25 to the control valve I9.

'Ihe main stream generator circulating pump The fuel oil tank is represented at 38 with itsl suction line 39, vent 50, filling line 48, and control valve therefor, 49, and burner by-pass return oil discharge lead GIA. Opening into the fuel line into the burner is a pipe having a control valve therein SID for introducing starting oil into the burner, and GIE is a valve for shutting off the oil normally used in the operation of the plant, while using the starting fuel oil. Pipe 28, constituting the exhaust lead from the auxiliary turbine 6, opens into the vmain turbine exhaust lead |0^.

Figures 5 and 6 show schematically arrangements similar to that shown in Figure 1. In Figure 5, the fuel air mixture and burned gases travel substantially parallel to the flow of Water in the steam generator tubes fitted with pressure drop devices at intermediate points of the length thereof, in accordance with the present invention. In Figure 6, the gases travel in a counter current direction to the direction of the flow of water.

Figures 7 and 8 show spiral sets of water wall generator tubes fitted with pressure drop devices 35 with each set having an individual circulating pump 26A, 26B, and 26C.

In Figure 9 is shown a complete high speed power plant embodying a highly eflicient boiler for use therewith. The circulating system for water, steam and fuel resembles that illustrated in Figure 1, and a detailed description of the duplicated parts will not be set forth below.

The central combustion chamber |06, as shown, has steam generator tubes 34 therein through which water is circulated from inlet header 33 to outlet header 36. The steam and water produced in accordance with the present invention, is discharged into the tubes 31 at the end of the boiler opposite the burner, and thence to the water level cylinder 8. Pipe 5| connects from the upper end of the cylinder 3 to deliver saturated steam therefrom to the super-heater tubes around the interior of the combustion chambers which are shielded by the steam generator tubes 34.

The combustion gases travel upwardly to the top end of the chamber, and then pass through passage |01 downwardly to the passage |08 con, taining spiralled economizer tubes. The gases pass therefrom through passages |09A to the air pre-heater passages ||0. The air in the present modification is introduced tangentially at the upper end of the burner through passage |00^ and passes into heat-exchanging relation to the spent combustion gases in its downward course to the burner chamber whereat it is admitted through the passages |03.

The spent combustion gases are exhausted from `the boiler to the' stack outlet 2|5.

The details of the boiler structure, described generally above, form the subject-matter of claims in others of my copendirg applications, and need not be described in greater detail in the present application which relates to the eilicient method of producing steam fully described above.

I claim:

1. The method of generating a vapor of high fluid in each of said fluid paths at a portion intermediate the ends thereof, combining the outputs of liquid and vapor from the several fluid paths in a space free from a liquid head, and separating the vapor for utilization for purposes of energy conversion from the liquid.

2. The ,method of generating steam which comprises circulating water in a plurality of fluid paths in heat exchanging relation to a source of heat to produce steam under pressure, restricting the flow of fluid in each of said fluid paths at a portion intermediate the ends there of, combining the outputs of water and steam from the several fluid paths in a space free from a liquid head, and separating the steam for utilization from the water for recirculation through said plurality of fluid paths.

3. The method of generating steam which comprises positively circulating a liquid in a plurality of fluid paths in heat exchanging relation to a source of heat to produce a vapor under pressure, restricting the flow of fluid in each of said fluid paths at a point other than the respective sources thereof, combining the outputs of liquid and vapor from the several fluid paths in a. space free froml a liquid head, and separating the vapor for utilization from the liquid for recirculation through said plurality of fluid paths.

4. The method of generating steam which comprises positively circulating a liquid in a plurality of fluid paths in heat exchanging relation to a source of heat to produce a vapor under pressure, restricting the flow of fluid in each of said fluid paths at a portion intermediate the ends thereof, combining the outputs of liquid and vapor from the several fluid paths, and separating the vapor for utilization from the liquid for recirculation through said plurality of fluid paths.

5. The method of generating steam vvhich comprisesorcibly circulating water in a plurality of fluid paths in heat exchanging relation to a source of heat and in a quantity greater than is evaporated in said fluid paths to produce steam, restricting the flow of fluid in each of said fluid paths at a portion intermediate the inlets and outlets thereof, combining the outputs of water and steam from the several fluid paths. separating the steam from the water, superlieating the steam for purposes of utilization, and

WALTER DOUGLAS LA MONT.

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