US1769457A

US1769457A - Steam-power plant

Info

Publication number: US1769457A
Application number: US362887A
Authority: US
Inventors: James A Powell
Original assignee: Foster Wheeler Inc
Current assignee: Foster Wheeler Inc
Priority date: 1929-05-14
Filing date: 1929-05-14
Publication date: 1930-07-01
Anticipated expiration: 1947-07-01

Description

y 1, 1930. J. A. POWELL 1,769,457

' STEAM POWER PLANT Filed May 14, 1 929 CONDENSER Y LR WIRE/IVE;

ATTORNEY NVENTO2 Patented July I 1930 UNITED sTATEs ejp ATENT OFFICE JAMES POWELL, OF INTERVILLA, PENNSYLVANIA, ASSIGNOR TO FOSTER WHEELER CORPORATION, 'OF NEW YORK, N. A CORPORATION, OF NEW YORK pressure prime movers.

to superheat the steam passing fromlalhigh STEAM-POWER PLANT Application filed May 14, 1929. Serial no, 362,887.

3 My invention relates to steam power plants and particularly to steam power plants having a plurality of prime movers operating within different-ranges of steam pressure. i

For high efficiency, it is desirable that steam of high superheat be supplied to high It is also desirable pressure prime mover to a low pressure prime mover. Th1s is often done by passing the inter-stage steam through reheaters,

for example a steam heated reheater and a flue gas heated reheater. arranged 1n serles.

If a high pressure prime mover is bypassed so that steam passes direct'to a low 7 pressure prime mover, the superheated steam may be too hot for the flue gas reheater.

' Not alone is suchsteam of the superheat of the source but the necessary throttling inthe by -pass adds heat of superheat. Consequently it is advisable to desuperheat the by-passed steam before. its passage through the flue gas heated reheater. The 'fluegas heated reheater cannot or should not be bypassed because it is likely to burn out.

In steam'power plants ofthis type, feed water isusually heated by steam. This is accomplished in' the final stage before the flue gas feed' heater by a closed heater, as distinguished from a thoroughfare heater; A thoroughfare heater is one in 1 which steam as steam passesthrough the heater while a closed heater is P one in which the heating steam is condensed.

I proposeto give such closed heater a double function byusing it merely asa feed heater during'normal operation and using it as a desuperheater when the high pressure- W prime mover. is .by-rpassedrbyipassingl the..by-'

- passed steam through it on its way to the reheaters and thus cooling the by-passed steamsufliciently to prevent excessively high temperature 1n the gas reheater. By this means- I obtain the desired and necessary conditions for the steam with a minimum of steam plant equipment.

The invention is illustrated by means of the accompanying drawing showing a steam power plant embodying the invention.

the waterin the boiler proper.

what is known as On' the drawing, reference character 10 designates 'a boilerwhich'inay' be of any of various types, suitablylheated and having a superheater 11 for superheating the steam after the disengagement of the steam from A flue 12 leads from the boiler and encloses a flue gas heated reheater or gas reheater 13 and a feed pumped through feed line- -16 into the feed water heater and from the feed water heater 'into the boiler through connection'17.

. Boiler steam passes through conduit 18 to 'a high'pressure prime mover, illustrated as erators 20and 30 maybe connected to the sameelectric circuit. Instead oftwo sepwater heater 14. Boiler feed water is r arate turbines, the high and low pressure prime movers may be different sections of a single turbine or other motor. connected to drive a single electric generator or other power consumer. Steam flow through the turbines may be controlled in a number of ways; One way is by a centrifugal gov-' 'ernor operated from the shaft of either turbine and arranged to control a supply valve 31 for the high pressure turbine.

Conduits '23 and 24 connect with the steam chamber 32 ofa feed water-heater 33. Feed.

lsvaterhimsuppliedito. the. feed-water heater by pump 34 and through conduit 35. The

water circulates through tubes Y 37 within the feed water heater'and is heated by the. steam. Thence the feed water passes through conduit 38 and through pump 15 into conduit 16. Condensate is withdrawn from, the feed water heater by pump 39 and forced into conduit 38.

In conduit '22 is a valve .40. In conduit 23 is a valve 41. In conduit 24 is a valve heater 26, throug and the condensate passes 42. Between conduit 18 and conduit 21 extends a by-pass conduit 43 in which is a' nection with conduit 21 of by-pass conduit 43 therewith. Thischeck valve is such as to prevent steam from passing through conduit 43 and back through conduit 21 into the high ressure turbine exhaust opening.

Steam or heater 26 is taken from the boiler, passes through conduit 49 and into a part 50 of the reheater. The steam is'condensed y v y through conduit 51 back to the boiler.

During normal operation, the main path of flow of steam is through superheater 11, through conduit 18, through high pressure rime mover 19, through conduit 21, through conduit 22, throu h conduit 25, through reconduit 27, through reheater 13, through conduit 28 and through low pressure prime mover 29 into the condenser. Condensate from the condenser asses back to the boiler as feed water. The eed water is heated in feed water heater 33 by steam which is tapped or bled from the main ath of steam' flow through conduit 45. This steam passes through conduit 23 into space 32 of the feed water heater where it is condensed as it heats the feed water in tubes 37 The amount of this steam.

for heating the feed water in heater 33 is small compared to the amount of steam passing in the main path of flow. Consequently conduit 45 can beof small size compared to the diameter of the conduits formmg the main path of flow. The condensed steam is returned by pump 39 to the boiler. When the high pressure prime mover is by-passed, the main path of flow is from superheater 11, through conduit 18, by-pass conduit 43, through the part of conduit 21- between conduit 43 and conduit 23, through conduit 23, through space 32 of heater 33, through conduit 24, through conduit 25 and thence on to the low pressure prime mover as in the case of normal operation. By-pass conduit 43 is of a size totake the amount 'of steam flow of the main path. The feed water is heated by the main path flowin this case and the. main path steam is desuperheated by the feed water. By this means the steam, which is .highly superheated as a result of the original superheating and the throttling through the valve or valves in the by-pass43 is reduced in tem perature so as not to permit excessive temperature in the flue gas heated reheater 13.

In a plant in which the high pressure prime mover is by-passed at times of decrease of load as in a plant using a steam accumulator connected in parallel with the high pressure prime mover which is charged for power or other purposes during heavy "fj" load, it may be desirable to control valves 40, 41, 42, 44 and 46 automatically. Valve 44 may be connected to the centrifugal governor for the turbine or turbines so that it opens when the speed exceeds a given value and mechanismmay be provided. whereby, when valve 44 is opened, valves 40 and 46 are automatically closed and valves 41and 42 automatically opened. For thispur'pose servo-motors for the various valves can be connected to a common relay controlled by thespeed of the turbine, or such an arrangement may be controlled from pressure 1n the steam supply line. In case ofmanual regulation, mechanism may be provided mter-connectingthe valves to operate to change the steam flow as abpve described when by-pass valve 44 is opened.

While I have shown a separate connection 45 for bleeding steam to be condensed in I the feed heater, this connection may be dispensed within which case valve 41 takes over the function of valve 44.

The heater may be provided with a vent for initiating circulation of steam therethrough and other supplemental devices customary to plant equipment of this type.

It will be understoodthat wide variations of plant layout are possible within the scope of the invention.

What I claim is:

1. That improvement in the operation of steam plants including a high pressure prime mover, a low pressure prime mover and a feed water heater and having a main path of steam flow including the high pressure and low pressure prime movers and a by-pass path of flow around the high pressure .prime mover which comprises withdrawing steam from said main path of flow to heat feed water in the feed water heater and 'thereby condensing the withdrawn steam and desuperheating the by-passed steam in the feed water heater by the cooling effect of feed water without condensing .low pressure motor and. for conducting steam from the high pressure motor into the feed. water heater and means to withdraw condensed steam from the feed water heater.

conducting feed water through the feed water heater, a conduit for conducting steam heater.

. JAMES A. POWELL.