US2652687A - Gas turbine power plant solid fuel feeding means - Google Patents

Description

GAS TURBN POWER PLANT SOLID FEL FELEDIING MEANS Filed NQv. 30. 1949l j Sept. 22, 1953 l l J. l. YELLo'r'lY :s sneetsfsheet 1 ATTORNEY J. l. YELLoTT 5 Sheets-Sheet 2 ATTORNEY sept. 22 1953 GS TURBINE POWER PLANT SOLID FUEL FEED-ING MEANS Filed NOV. 30, 1949 J. YELLOTT Sept. 22, 1953 GAS TURBINE POWER PLANT SOLID FUEL. FEEDING MEANS Filed Nov.. 30, '1949 3 Sheets-Sheet 3 ATTORNEY Patented Sept. 22', 1953 assis GAS TURBINE POWER PLANT SOLID FUEL f FEEDIN G MEANS John I. Yellow, Baltimore, Ma., assigner m Bituminous Coal Research, Ine., Washington, D. C., a corporation of Delaware` Application November 30, 1949, Serial No. 130,215

17 Claims. (Cl. (l0-39.46)

In the transfer of particulate solids, such as` crushed coal, from a hopper maintained at atmospheric pressure, into a pressurized air stream for delivery through a nozzle pulverizer into a pressurized lcombustor, as disclosed in my application Ser. No. 691,307, filed August 1'7, 1946, for Coal Fired Gas Turbine Power Plants, it has been found necessary to use multiple hoppers with air locks, and to connect the air locks with the pressure delivery line to balance the pressure in the hoppers and prevent blow back of the pressurized fluid into the hoppers. It has also been found necessary to provide specialequipment for controlling the quantity of crushed coal introduced into the pressurized combustor feed line, as Well as other equipment for selectively withdrawing or stripping desired quantities of the fluidized solid particles from the feed line, at will, in order to vary the ratio of solids to carrier fluid and thereby vary the volume of gases generated in the combustor.

It` has now been found that the feeding of crushed coal, or other frangible solids, into a pressurized pneumatic feed line, can be carried out more accurately, expeditiously, and-economically, by the utilization of the improved rotary solids pressurizer of the present invention, in which the features of novelty and advantage include the introduction of the particulate material, in a free falling stream, into peripheral pockets of a feeder wheel, which pockets are configured to presentan axis which is determined as the hypoteluse of a right triangle whose side is the vector of particle velocity of thefree falling particles, and Whose base is the vector of the tip velocityof the pockets.

The fundamental principlev of operation of `this pump is as follows:

The rotor, which is shaped like a large gear wheel or milling cutter, and is provided with teeth on its periphery, within a rigid gasing, but without actual contact between the rotor and the casing. I have found that, if the clearances between the rotor and the casing are made very small, less than 6/1000ths of an inch, the leakage of air and coal through such clearances is reduced to a feasible amount, and the abrasion of the moving part of the pump is kept to a minimum, because no rubbing seals are required to reduce the leakage below the value Which-is obtained by virtue of the small clearances.

In `the operation of the preferred form of the pump as incorporated in a pressurized combustion system, to be described more fully hereinafter, the coal is dropped into the top ofthe pump from a height suflicient to give the coal particles a velocity of about 3 feet per second, and the tip speed of the rotor is also about 3 feet per second. The relative4 velocity of the coal to the rotor is thus about 4 feet per second, and is inclined at an angle of approximately 45 to the peripheral surface of the rotor. The teeth of the rotor are preferably spaced at this angle, to enable the coal to fall smoothly into the pockets. No side plates are provided on the pockets, because the coal is removed from the pockets, after they have rotated from the filling zone to the discharge point, by blowing air transversely across the face of 'the rotor, parallel to the shaft. stream not only picks up the coal from the rotor pockets, but also carries the coal on to'the pulverizer and the combustion system.v

'I'here has thus been provided a simple means for filling the pockets, despite the fact that the rotor is turning at a speed of approximately R. P. M., and for discharging the coal from the rotor into a flowing air stream. In actual tests, the pressure in this air stream was as much as p. s. i. a., and there seemed to be no reason why the pressure could not be at least doubled.

Leakage across the face of the rotor is prevented by means of seals which are set in the casing and are caused to press against the two faces of the rotor. A vent is preferably provided on the sides of the casing, to allow the escape of the air which leaks under these seals. A vent is also providedto discharge the air which is carried around by the rotor pockets from the coal pickup line. It is important that this leakage be discharged before the pockets enter the nlling zone. A vent is' providedin the filling region, in order 4to allow the escape of the air which will leak through the narrow clearances between the rotor and the casing.

The rotor of the pump is driven by any appro- This air priate means. with its rotation rapid enough to minimize pulsations in the coal flow.

In the operation of the pump, an outboard bearing is used to prevent the rotor from beiner displaced because of the air pressure under the rotor.

In summary, the present invention is directed to a power plant of the character described utilizing and incorporating a coal-feeding device which will take a powdered material from atmospheric pressure, carry it into a casing provided with clearances less and M000 inch and deliver it to a flowing air stream. The fundamental principle is the maintaining of small clearances without rubbing seals in the pocket area. Inactual test, with an air pressure of 100 p. s. i. a., and an` airy ilow through the delivery pipe of 1600 lbs. per hour, the leakage of air through the vent system was approximately 60' lbs. per hour. and the leakage of coal was negligible.

It is, therefore, among the features of novelty and advantage of the present invention to provide an improved coal-burning power plant, desirably of the generating electric type in which the generators are powered by a gas turbine utilizing motive fluid derived from the pressurized combustiony of crushed or powdered coal, and characterized by the incorporation of special coal treating and delivery means; other features of novelty and advantage include the use of special rotary transfer pumps for the transfer of particulate coal from atmospheric storage means into pressurized combustive air feed lines of combustors of motive fluid generators: the drying of bunker coal by turbine exhaust gases; the intercooling and aftercooling of combustive air used for the delivery of particulate coal from the solids transfer pump to the pressurized combustor; the use of surge control means and demand control means for the pressurized combustive air feed line.

The above and other features of novelty and advantage of the present invention will be described With reference to a novel power plant incorporating one form of the novel rotary feeder as illustrated in the drawings, and in which Fig. 1 is an exploded view of the feeder with the outboard bearing-plate in section;

Fig. 2 is a vertical axial section of the feeder;

Fig. 3 is a view taken on line 3-3 of Fig. 2 showing the inboard side f the feeder wheel and the mode of filling and discharging the pockets;

Figs. 4 and 5 are sectional details of the bearing rings and mountings Fig. 6 is a vector diagram illustrating the coincidence of the vangle of fall into the feeder pockets with the pocket angle, and

Fig. rI is schematic showing of a coal burning gas turbine power plant incorporating the novel feeder herein.

To facilitate an understanding of the claimed invention, and the special role in the combination entity played by the solids transfer pump, the latter will be described in detail before proceeding with the description of the novel power plant incorporatingthe same.

Referring now to the drawings, and more particularly to the showings of Figs. 1-3, the novel, pressurizer will be seen to comprise the following sections or parts: a body or housing I0; an outboard face and bearing plate 20; a feeder Wheel 30; shaft 40; shaft housing 50, and feed hopper The housing I0 is a cup shaped member having a generally cylindrical body or wall I I, and an integral, inboard face and bearing plate, I2. The housing is provided with a flat upper surface I3. parallel to, a plane of the axis, and a flat outer surface I0 normal to the axis. The interior surface of section Il forms a chamber with the inner surface of inboard face plate I 2, which is axially apertured at I l to receive the shaft 40, and countersunk at Il, to receive the shaft packing I5'. While the inboard face plate I`2 of the pump is shown as integral with the housing wall or body II, it is to be understood that the parts may be separate members, secured in any suitable manner. The face plate I2 is provided further with a ring groove I8, concentric with the shaft, and connected through duct I6' to a pressure fluid source, not shown. The upper edges of the inner surface of pump body Il are chamfered. as indicated at II', with at least one vent I1 formed 4directly below one such chanifered section. A discharge opening I8 is formed in plate I2 inthe vertical plane of, and below the axial aperture I4. The outboard face l0 of the pump housing is tapped and threaded, as indicated generally at I9, to receive machine screws 2I which serve to secure detachable outboard face plate 20 in position against the housing. The upper facev I3, of the pump housing is also tapped and threaded as shown at I3. f

The detachable outboard face plate 20 is conformed to housing I0, and is secured thereto by machine screws 2l. Its inner face 22 is at, and is provided with a ring groove 23 connected, through duct 23', to a common fluid source with duct I6. The outer face 24 of plate 20 is countersunk about axial shaft hole or bearing 25 to receive packing 26. The upper, flat surface 21 of the plate 20, is coplanar with face I3 of the pump housing I0, and is tapped and threaded, as indicated at 21'. Upstream air inlet 29 is in axial alignment with discharge outlet I8, and in vertical alignment with shaft bearing 25.V

The feeder wheel 30, as shown, is a solid cylinder having parallel flat faces 3l, 32, respectively perpendicular to the axis of central shaft aperture 33. Face 32 is countersunk to provide a coaxial socket 34, and a surface depression 35. A series of peripheral pockets 36 are separated by vanes 31 having peripheral faces 38. The vanes 31, as shown, are inclined at an angle of approximately 45 to the diameters passing through diametrically opposite vane tips.' The identical ring grooves I6, 23, seat identical ring gaskets or sealing members 39 which are biased in self-seating, non-galling, bearing engagement against the faces of the rotor 30, and inwardly of the pockets, all as will be described more in detail hereinafter. The pockets 36, in the preferred form of the invention herein shown, are 16 in number, and it is found desirable to have a large number of small pockets, rather than a few large pockets. With a constant speed of the rotor, the number of pockets should be great of the rotor canbe appreciably reduced,| the performance of the pump greatly improved, and operating diiliculties reduced in proportion.

40. This shaft has a main body portion 4I having bearing engagement in the inboard face plate I2 and inboard bearing 50, secured to the face plate or formed integral therewith. The outboard section of the shaft is stepped down, as indicated at 42, to provide a rotor engaging section, the outboard portion of the section 4'2 being threaded, as indicated at 43, to receive lock nut 44, which is turned up on the thread to have locking bearing engagement against the base.of socket 34. The outboard end of the shaft is further reduced in diameter, as indicated at 45, and bearing support in the axis 25 of outboard face plate 20. The shaft is suitably packed in the packing 26 and its tip end extends beyond face 24 of the face plate. The tipend 46 is covered by a cap 41, which issecured to the face plate in any suitable manner, as by screws 48.

The inboard bearing vmember 58 is of generally cylindrical construction,and .is provided with a body portion 5I centrally apertured at 52 tofreceive main section 4I of shaft 48. The member 50 is flanged at its outboard end, as indicated at 53, and'is secured to the face plate I2 in any suitable manner. The inboard end of the lshaft bearing 53 also is flanged, as indicated at 54, and provides a bearing for hollow cap 55, which is suitably packed to provide lubrication for the inboard end of section 4| of the shaft. The cap 55 is secured to flange -54 by machine screws 56, as shown in li'ig. 1, and serves as a thrust bearing for the shaft. The inboard end ofthe shaft is reduced, as shown at 41 (Fig. 3), to receive gear wheel 48 in a drive or keyed t. The gear is locked in position by nut 41' which engages the threaded end 41" of the shaft. A pinion gear 49, mounted on shaft 49', meshes with and serves to drive the gear wheel 48.

The feed hopper 60' comprises a generally rectangulan'box-like body portion 6I with converging bottoml portions 62 integra-l with bottom flange'plate 63. The plate 63 is apertured at the corners, as indicated at 64. The apertures 64 are severally aligned with the tapped holes I3', 21' in the inboard and outboard face plates respectively. The flangev plate 63 is secured on and over the fiat topsurface of the assembled pump by machine screw 63. The top of the rectangular body section 6I of the hopper is flanged, as shown at 65, to provide -a bearing surface for cover plate of the feed mechanism. At one side, the body section 6I of the hopper is aper- I pipe 1I and a vent pipe 12. 'On the under .sur-

face of the plate 1B and below the inlet to pipe 12 is mounted a baffle plate 13, desirably welded or otherwise secured to the plate. The feed line 1I is preferably arranged at one end of plate 10 so that its axis is in substantial alignment with the opening of a pocket 36 of the feed wheel 38, with the trailing edge of the pocket opening coinciding with lthe bottom edge of the rear chamfer II' of the pump casing.

- in each pocket is blown out of the poc the particulate solids 80 are dropped through feed line 1I into the hopper 60. Because of the\arrangement of the parte the solids fall freely-into the first empty pocket 36 of rotor 3l) which is clearing the pump casing II in its rotation. -Asy the rotor turns, the pockets, severally charged with uniform charges of loose material, travel around the inside of the pump casing until they are lseverally and consecutively brought into 28. At this point the charge of solid particles into the solids discharge line I8 as a streaming entrainment of solid particles in a pressurized gaseous fluid. As the rotor continues to rotate the empty pockets successively move into alignment with vent aperture I 1 of the pump casing, and the pressure air contained in each pocket is vented through conduit 61, and opening 66 into the feed hopper 60, thence to the atmosphere through vent line 12.

In the operation of the improved solids transfer lpump herein, best results are obtained when vthe rotor of the pumpis operated at a uniform speed, and the quantity of solids transferred is varied by varying the rate of feed -or quantity of solids introduced into the pump in the solids stream 80. capacity of the pockets 36 to receive a maximum unit quantity, it is-possible to vary the amount of solids transferred by the pump solely by vary- 'ing the rate of feed of the solids contained in solids stream 80. Thus the pump may be operated with the amount of solids transported, per pocket, per rotation of the wheel, varying from zero to a maximum. Because of the number of pockets, the successive pulsating discharges of solids from pockets 38 into the line I8 will be so rapid that the pulsations will overlap, and an essentially uniformly dispersed stream of solids will be transported and delivered by the pressure line I 8. This, particularly in view of the fact that it is found that, even with pulsating charges of solids introduced into a pressure stream of constant velocity and uniform pressure, there is substantially immediate and uniform dispersion of the solids immediately beyond the point of introduction into the pipe I8.

The determination of the proper pocket size and angle of inclination of the pocket walls 31, as noted hereinabove, is relatively simple and can be determined using the vector diagram of forces shown in Fig. 6. Thus, with the vector of the coal velocity serving as a vertical component, and the vector of the tip speed of the walls of the pockets at right angles to the coal velocity vector, the relative velocity of the freefalling coal particles is determined as the hypotenuse of the vector triangle formed. With the angular relation between the coal velocity and the relative velocity established, the axis of the pockets will bear the same relation to the tips of the walls 31 as the hypotenuse of the ,vector triangle does to the base of the triangle. As indicated above, the improved performance of the solids transfer pump in transferring solids from one pressure level to another, and without blow-back or appreciable leakage fromthe high pressure side to the low pressure side, is made possible by the special structural features of the device. Of these features. of prime importance is the fabrication and assemblage of the parts in such a manner that the gap or clearance between the tips of the pocket walls, or the periph- In operation, and as shown in detail in Fig. 3, '15 ery of the rotor, and they inner surface of the alignment with the opening of the air feed pipe Y By calibrating the pocket size or t' pump chamber should be not more than onehalf the diameter of the average size of the particles it is proposed to handle. Secondly, the provision of self-adjusting and self-seating, nonseizing, self-lubricating, annular sealing members in the inner faces of x'he pump casing, biased into positive, constant sealing engagement against the faces of'the rotorwheel, and immediately below the roots of the pocket walls,

insures that the solid particles will be prevented from being driven inwardly of the feeder wheel to the shaftsection and into the shaft bearings. This condition is insured by applying a positive pneumatic fluid pressure to the shaft housings with discharge radially to the pump chamber from the axis of the rotor across its faces to the sealing members 39. In this manner a positive outward pressure is applied to the pump chamber radially of the rotor shaft and any tendency for particulate material to ow back into the shaft section under the inuence of the pneumatic pressure in the pump chamber will be essentially overcome.v

Desirably the non-seizing, self-seating, sealing rings or gaskets 39, are made of self-lubricating bearing metals, or like compositions, such as copper-lead or copper-graphite material. By supplying air, under pressure, to the ducts I6', the groove I6 in which the sealing rings 39, are seated, the rings can be caused to have any desired sealing engagement against the rotor faces. With the air fed into the grooves i6, 23, at a pressure above that obtaining in the line 28, any leakage of air past the sealing rings will have to flow radially outward, to the outside 8 air stream and pulverization of the entrained coal to flour iineness, whereby a pressurized, combustive. aeriform stream of air-borne pulverized coal is continuously generated and discharged to coal burners H2 of combustors H3. The products of combustion plus heated compressed air (secondary air) from regenerator IH, mounted in the stack of turbine H5, are mixed to form a high temperature, pressurized motive fluid for the turbine. This motive uid is passed through ash separator H6, wherein the ash is separated and removed through ash discharge ||1, the cleaned motive uid then passing 'through line I 8 to the turbine H5, wherein it is expanded, doing work. The expanded gases discharge through the stack,in heat exchanging relation with the compressed air from main, low pressure compressor H0, which, as noted, discharges through the regenerator into the combustor, as secondary air, to mix with the products of combustion of the flames and form the motive iluid for the turbine. The primary air or pressure uid of line I I0 comprises compressed air taken from the discharge duct of compressor H9, and then passed through intercooler |20, booster compressor l2|, and line |22, to the rotary coal transfer pump I0. 'I'he high pressure line |22 is in heat-exchanging relation with a surge control means comprising an after-cooler |23, having the usual coolant entrant, and a coolant discharge line |24, controlled by valve |25. .'Ihe after-cooler coolant system may be operated with a yrecirculated coolant which is passed through an air or water cooledV `combustive air line |22 discharges a constant in a pneumatic line to form a uidized solid y stream of combustible particles which are fed to a combustor and burned, under pressure, to provide motive fluid for gas turbines.

In Fig. 7 I have illustrated a power plant of the turbine-driven, generating electric type, in which bunker coal is preliminarily coarse ground and fed to an atmospheric storage tank, from which it is discharged, through a solids feeder or pump, to a pressurized air stream in which it is reduced to flour nneness and burned in a combustor to supply motive gases for a gas turbine.

In the system there shown, bunker coal is stored in a coal bunker |0| having a Stoker feed |02 driven by a stokei` driver or air motor I 03. Desirably, drying air is taken from the turbine exhaust through line |044 and delivered into the discharge end of the stoker.

may be vented to the atmosphere as illustrated.

-Dry coal is fed into a crusher |05, incorporating a magnetic separator |06, and discharged thence, through coal conveyor 01, to a atmospheric storage tank |08. On demand, the coal is fed through coal feeder 60 vand :.,otary coal transfer pump I0, to primary combustive air feed line |0, the resulting air-borne dispersion of crushed coal particles passing through nozzle pulverizer III, with simultaneous reduction in pressure of the After traversing the length of 'the stoker and drying the coal, it

volume of primary air through the rotary coal transfer pump i0, air-solids feed line ||0, and convergent nozzle pulverizer III,y to the coal burners H2, any variation in the quantity of motive fluid generated is controlled by and is a function of the varying oi.' the ratio of solids to primary, combustive air in the combustor feed line. With the -novel rotary solids feeder herein, functioning as a coal transfer pump, any desired ratio of coal solids to combustion air can be obtained readily by simply varying the amount of solids in the solids stream 00 fed to the rotary coal transfer pump I0.

While a coal burning gas turbine power plant has been shown and described as a preferred system in which the novel solids pressurizer may be incorporated to distinct advantage, it is to be `understood that the rotary solids transfer pump the turbine including a rst low pressure secondary air compressor, a second, high pressure,

combustive air compressor, a coal bunker, a coal crusher fed from the bunker and discharging crushed coal to a crushed coal storage means, and a combustor; and solids feed means from the coal storage means to the combustor incorporating a variable delivery, crushed solids feeder, a constant speed rotary transfer pump, and a pneumatic solids feed line connecting the high pressure compressor and the combustor, said"- feeder discharging' into the said feed line through said pump. and a secondary air feed line connecting the first said compressor to the combustor, whereby the products of combustion of the coal and combustive air are diluted and reduced to optimum turbine operating temperature.

2. Generating electric power plant according to claim 1, characterized by the fact that the crushed coal storage means is maintained substantially at atmospheric pressure.

3. A generating electric power plant including a coal fired gas turbine, a generator driven by the turbine. a source of heated motive gases for the turbine including a first low pressure secondary air compressor driven by the turbine, a second, high pressure primary, combustive air compressor, a coal bunker, a coal crusher fed from the bunker and delivering crushed coal to a'storage means, a combustor, a crushed coal.

feed line from the coal storage means to the combustor incorporating a variable delivery, crushed solids feeder and a vconstant speed rotary transfer pump, said feeder discharging into the said feed line through said pump, pneumatic conduit means delivering high pressure air from the second compressor to the crushed coal feed line, pneumatic conduit means delivering low pressure air from the first compressor to the combustor,and means delivering heated motive gases from the combustor to the turbine and incorporating ash separating means.

4. A generating electric power plant including a coal ilred gas turbine, a lgenerator driven by the turbine, a source of heated motive gases for the turbine including a first low pressure secondary air compressor driven by the turbine, a second, high pressure primary, combustive air compressor, a coal bunker, a coal crusher fed from the bunker and delivering crushed coal toa storage means, 4a combustor, a crushed coal feed line from the coal storage means to the combustor incorporating' a variable delivery, crushed solids feeder and a constant speed rotary transfer pump, said feeder discharging into the said feed line through said pump, pneumatic conduit-means delivering high pressure air from the second compressor to the crushed coal feed line, pneumatic conduit means delivering low pressure air from the first compressor to the combustor, means delivering heated motive gases from the combustor to the turbine and incorporating ash separating means, and means for regenerativeiy heating the low pressure air delivered from the rst compressor to the combustor.

' 5. A generating electric power plant including a 'coal ired gas turbine, a generator driven by the turbine, a source of heated motive gases for the turbine including a first low pressure secondary air compressor driven bythe turbine, a second, high'pressure primary, .combustive air coinpressor, a coal bunker, a coal crusher fed from the bunker and delivering crushed coal to a storage means. a combustor, a crushed coal feed line from'the coal storage means to the combustor incorporating a variable delivery, crushed 10 solids feeder and a constant speed rotary transfer pump, said feeder discharging into the said feed line through said pump, pneumatic conduit means delivering high pressure air from the second compressor to the crushed coal feed line, pneumatic conduit means delivering low pres` sure air from the rst compressor to the combustor, means delivering heated motive gases Qfrom the combustor to the turbine and incorporating'ash separating means, means for delivering turbine exhaust gases to the coal bunker whereby to dry coal fed to the coal crusher, and means for regeneratively heating the low pressure air deliveredv from the first compressor to the combustor.

6. A generating electric power plant including a gas turbine, a generator and a low pressure secondary air compressor driven by the turbine, a source of heated motive gases for the turbine, including said low pressure compressor. a second high pressure primary, combustive air compressor, a coal bunker, a coal crusher fed from the bunker, and delivering crushedvcoal to a storage means, a combustor, means for delivering crushed coal from the said storage means to a pneumatic conduit feed line, comprising a gravity feeder discharging into a rotary pump, said rotary pump having discharge means registering with and in said pneumatic conduit, means delivering high pressure air from the second compressor to said pneumatic conduit, whereby to form a streaming entrainment of air-borne fluidized coal particles in a combustive air stream, and means for separately delivering secondary air and said combustive air-borne coal to the combustor.

7. A generating electric power plant including a gas turbine, a generator` and a low pressure secondary air compressor driven by the turbine, a source of heated motive gases for the turbine, including said low pressure compressor, a second high pressure primary, combustive air compressor, a coal bunker, a coal crusher fed from the bunker and delivering crushed coal to a storage means, a combustor, means for delivering crushed lcoal from the said storage means to a pneumatic conduit freed line, comprising a gravity feeder discharging into a rotary pump, said rotary pump having discharge means registering with and in said pneumatic conduit, means delivering high pressure air from the second compressor to said pneumatic conduit, whereby to form a streaming entrainment of air-borne iluidized coal particles in a combustive air stream, means for delivering said combustive air-borne coal particles to the combustor, regenerative air heating means delivering low pressure air from the first compress or to the combustor, and means delivering heated motive gases from the combustor to the turbine and including ash separating means.

8. A generating electric power plant including a gas turbine, a generator and a low pressure secondary air compressor driven by the turbine,

' a source of-heated motive gases for the turbine,

delivering high pressure air from the second compressor to said pneumatic conduit, whereby to form a streaming entrainment of air-borne uidized coal particles in a combustive air stream, means for delivering said combustive air-borne coal particles to the combustor, regenerative air heating means delivering low pressure air from the first compressor to the combustor, means delivering heated motive gases from the combustor to the turbine and including ash separatingmeans, and means for delivering air from the first compressor to the second compressor including an intercooler.

9. A generating electric power plant including a gas turbine, a generator and a low pressure secondary air compressor driven by the turbine, a

source of heated motive gases for the turbine, including said low pressure compressor, a second high pressure primary, combustive air compressor, a coal bunker, a coal crusher fed from the bunker and delivering crushed coal to a storage means, a combustor, means for delivering crushed coal from the said storage means to a pneumatic conduit feed line, comprising a gravity feeder discharging into a rotary pump, said rotary pump having discharge means registering with and in said pneumatic conduit, 4means delivering high pressure air from the second compressor to said pneumatic conduit, whereby to form a streaming entrainment of air-borne fluidized coal particles in a combustive air stream, means for delivering said combustive air-borne coal particles to the combustor, regenerative air heating means delivering low pressure air from the first compressor to the combustor, means delivering heated motive gases from the combustor to the turbine and including ash separating means, means for delivering air from the first compressor to the second compressor including an intercooler and a demand pressure regulator mounted across the second compressor.

10. A generating electric power plant including a gas turbine, a generator and a low pressure secondary air compressor driven by the turbine, a source of heated motive gases for the turbine, including said low pressure compressor, a second high pressure primary, combustive air compressor, a coal bunker, a coal crusher fed from the bunker and delivering crushed coal 'to a storage means, a combustor, means for delivering crushed coal from the said storage means to a pneumatic conduit feed line, comprising a gravity feeder discharging into a rotary pump, said rotary pump having discharge means registering with and in said pneumatic conduit, means delivering high pressure air from the second compressor to said pneumatic conduit, whereby to form a streaming entrainment of air-borne fluidized coal particles in a combustive air stream, means for delivering said combustive air-borne coal particles to the combustor, regenerative air heating means delivering low pressure air from the rst compressor to the combustor, means delivering heated motive gases from the combustor to the turbine and including ash separating means,

' means foi` delivering air from the ilrst compressor to the second compressor including an intercooler and a demand pressure regulator mounted across the second compressor, and surge control means in said high pressure air line.

1l. A generating electric power plant including a gas turbine, a generator and a low pressure secondary air compressor driven by the turbine, a source of heated motive gases for the turbine, including said low pressure compressor, a second high pressure primary, combustive air compressor, a coal bunker, a coal crusher kfrom the bunker and delivering crushed coal to a storage means, a combustor, means for delivering crushed 'l coal from the said storage means to a pneumatic conduit feed line, comprisingv a gravity feeder discharging into a rotary pump, said rotary pump having discharge means registering with and in said pneumatic conduit, means delivering high pressure air from the `second compressor to said pneumatic conduit, whereby to form a streaming entrainment of air-borne fluidized coal particles across the second compressor, and surge control means in said high pressure air line.

12. A generating electric power plant particularly adapted for use in coal burning locomotives. including a coal red gas turbine, a generator driven by the turbine, a source of heated motive gases for the turbine including a rst low pressure secondary air source, a second higher pressure primary, combustive air source, a coal bunker, a coal crusher fed from the bunker and delivering crushed coal to a storage means, a combustive unit, a crushed coal feed line from the coal storage means to the combustive unit, pneumatic conduit means delivering high pressure air from the second said air source to 'the crushed coal feed line, pneumatic conduit means delivering compressed air from the rst said air source to the combustive unit, means delivering heated motive gases from the combustive unit to the turbine and incorporating ash separating means in advance of the turbine, said crushed coal feed line including a rotary coal transfer pump, whereby crushed coal is transferred from the crushed coal storage means to the combustive unit as a combustible streaming entrainment of`combustive air-borne uidized coal particles in a pressurized air stream.

13. A generating electric power plant particularly adapted for use in coa-l burning locomotives including a coal fired gas turbine, a generator driven by lthe turbine, a source of heated motive gases for the turbine including a rst low pressure secondary air source, a second higher pressure primary, combustive air source, a coal bunker, a coal crusher fed from the bunker and delivering crushed coal to a storage means, a combustive unit, a crushed coal feed line from the coal storage means to the combustive unit, pneumatic conduit means delivering high pressureair from the second said air source to the crushed coal feed line, pneumatic conduit means delivering compressed air from the rst said air source to the combustive unit, means delivering heated motive gases from the combustive unit to the turbine and incorporating ash separating means in advance of the turbine, means for delivering turbine exhaustgases to the coal bunkerv .whereby to dry coal fed to the coal crusher, said crushed coal feed vline including a rotary coal transfer pump, whereby crushed coal is transferred from-the crushed coal storage means to' the combustive unit as a combustible streaming 13 entrainment of air-borne uidized coal particles in a pressurized air stream.

14. A generating electric power plant particularly adapted for use in coal burning locomotives including a coal fired gas turbine, a generator driven by the turbine, a source of'heated motive gases for the turbine including a rst low pressure secondary air source, a second higher pressure primary, combustive air source, a coal bunker, ak coal crusher fed from the vbunker and delivering crushed coal to a storage means, a combustive unit, a crushed coal feed line from the coal storage means to the combustive unit, said feed line incorporating a pulverizer, pneumatic conduit means delivering high pressureI air from the second said air source to the crushed coal feed line, pneumatic conduit means delivering compressed air from the rst said air source to the combustive unit, means delivering heated motive gases from the combustive unit to the turbine and incorporating ash separating means v in advance of the turbine, and means for delivering turbine exhaust gases to the coal bunker whereby to dry coal fed to the coal crusher, said crushed coal feed line including a rotary coal transfer pump, whereby crushed coal is transferred from the crushed coal storage means to the combustive unit as a combustible streaming entrainment of .combustive air-borne uidized coal particles in a pressurized air stream.

15. Generating electric power plant according to claim 14, characterized by the fact that the pulverizer in the feed line incorporates a nozzle.

16. A gas turbine power plant, including a coal fired gas turbine, mechanical power take-off rneans driven by the turbine. a source of heated motive gases for the turbine including a rst low pressure secondary air source, a second higher pressure primary, combustive air source, a coal bunker, a coal crusher fed Afrom the bunker and delivering crushed coal to a storage means, a combustive unit, a crushed coal feed line from the coal storage means to the combustive unit, pneumatic conduit means delivering high pressure air from the second said air source to the crushed coal feed line, pneumatic conduit means delivering compressed air from the first said air source gas turbine, mechanical power take-off means driven by the turbine, a source of heated motive gases for the turbine including a first low pressure secondary air source, a second higher pressure primary, combustive airA source, a coal bunker, a coal crusher fed from the bunker and delivering crushed coal to a storage means, a combustive unit, a crushed coal feed line from the coal storage means to the combustive unit, said feed line incorporating a pulverizer, pneumatic conduit means delivering high pressure air from the second said air source to the crushed coal feed line, pneumatic conduit means delivering compressed air from the first said air source to the combustive unit, means delivering heated motive gases from the combustive unit to the turbine and incorporating ash separating means in advance of the turbine, and means for delivering turbine exhaust gases to the coal bunker whereby to dry coal fed to the coal crusher, said crushed coal feed line including a rotary coal transfer pump, whereby crushed coal is transferred from the crushed coal storage means to the combustive unit as a combustible streaming entrainment of air-borne fiuidized coal particles in a pressurized air stream.

JoHN I. YELLo'r'r.

References Cited in the ille of this patent UNITED STATES PATENTS Number Name Date 730,782 Morrison June 9, 1903 738,133 Weaver Sept. 1, 1903 810,989 Steinert Jan. 30, 1906 941,024 Mantius Nov. 23, 1909 1,279,804 Welcker Sept. 24, 1918 1,321,262` Townsend Nov. 11, 1919 1,882,861 Moore Oct. 18, 1932 1,901,203 Thompson Mar. 14, 1933 2,244,050 Cassiere June 3, 1941 2,259,967 Vogel-Jorgensen Oct. 2l, 1941 2,280,765 Anxionnaz et al. Apr. '21, 1942 2,310,552 Schaaf Feb. 9, 1943 2,413,293 Colburn Dec. 31, 1946 2,573,949 Blizzard Nov. 6, 1951 FOREIGN PATENTS Number Country Date Great Britain May 3, 1938

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