US1594383A - Power plant - Google Patents

Description

Aug; 3 1926. 1,594,383

J. RUTHS ET AL POWER PLANT 7 Filed July '15, 1922, s Sheets-Sheet 1 Half/75 J. RUTHS ET AL POWER PLANT Filed Ju1y-l5 1922 5 Sheets-Sheet 2 Aug. 3 1926. 4

J. RUTHS ET AL POWER PLANT Filed July 15, 1922 I5 Sheets-Sheet 5 lll-llll 25 50 Patented Aug. 3, 1926.

UNITED STATES PATENT OFFICE.

JOHANNES RUTHS, OF DJ'URSI-IOLM, SWEDEN, AND EMIL JOSSE, 0F BERLIN, QERMANY, ASSIGNORS TO AKTIEBOLAGET VAPORACKUMULATOR, 0F STOCKHOLM, SWEDEN, A

CORPORATION.

POWER PLANT.

Application filed July 15, 1922, Serial No. 575,165, and in Sweden July 22, 19 21.

Our invention relates to power plants and more particularly to power plants equipped with internal combustion motors such as Diesel engines, and with steam consumers, and still more particularly wherein the main load of the plant is taken up by internal combustion motors.

One purpose of our invention is to provide a power plant of high efficiency. A further purpose of our invention is to provide a power plant wherein all the heat contained in the exhaust gases of internal combustion motors can be utilized and wherein variations between power productionand power and heat consumption are equalized.

Our invention comprises a novel method of operating a power plant wherein an internal combustion unit is operated at uniform load, exhaust gases are conducted from the internal combustion unit to a steam generator to heat the same, steam is led from the steam generator to steam consumers or to a steam accumulator or both and steam is taken-from the steam accumulator to take care of peaks in load;

Our invention also comprises a, novel power plant arrangement including an internal combustion engine unit, means to operate said unit at substantially uniform load, a steam generator, means to conduct the exhaust gases from said internal combustion engine unit to said steam generator, a regenerative accumulator, means to conduct steam from said generator to said accumulator, consuming means and means to conduct steam from the accumulator to the consuming means to take care of peak loads.

Further features of the invention will be apparent as the description proceeds.

To illustrate the invention, suppose a motor operates with an efficiency of 24%. To provide one horse-power-hour, which is equal to 2547 British thermal units or 632 kilogram-ca1ories, there would be consumed 1n this motor ;=approximately'i i or I v 2 approximately 2,600 kilogram-calories Of thisdast'value, about 33%, which is 3,500 B. t. 11.."01 860 kilogram-calories, will each horse-power-hour generated by the internal combustion motors there is enough heat remaining in the exhaust gases to generate 0.2 horsepower-hour.

Thus, if the exhaust gases can be entirely utilized it is possible to obtain power therefrom to the extent of 20% of the power produced by the motor. Since the average value of the peak load in a plant usually amounts to this value it is possible to run the motors at uniform load and therefore with the highest possible economy if proper utilization is made of the power in the exhaust gases.

Our invention makes possible the utilization of the entire heat content of the exhaust gases as above outlined and consists in the p method, construction, arrangement and combination of elements hereinafter set forth, pointed out in the claims and illustrated in the accompanying drawings, in which Fig. 1 illustrates a representative chart of steam consumption in a plant such as that dealt with herein and indicates the mode of operation of the plant.

Figures 2, 3 and 4 show various modifications of our invention in which:

Fig. 2 is one embodiment wherein a socalled over-flow valve is used. I

Fig. 3 is an embodiment wherein all the steamgenerated in the boilers is led through a motor before passing to the consumers.

Fig. 4 is an embodiment somewhat similar to Fig. 3 whereina compound motor is used, in the specific illustration shown, an extraction turbine.

Fig. 5 is another load chart of a plan indicating a difi'erent mode of operation.

In Fig. 1 is shown a load diagram of a plant. In this diagram abscissae represent time and the ordinates represent load. Line 0 represents the base load. To this load,

thus the line I) is obtained. The total demand for power is indicated by curve 0. The difference between curve and hue a ma be said to represent the peak load. The di ference between lines 5 and a is substantially the average of the peak load. As the diagram shows, there exist, at certain times, peaks 6 above the line b, which would have tobe covered by over-loading the motors at hand or by obtaining power from another source, were it not for the present invention. At-other times, the demand for energy is below the line I; and, with the present invention, there is then a surplus of energy generated, designated by the shaded surfaces below line b, which energy is accumulated. Were the motors to be operated in conjunction with steam generators heated by exhaust gases, but without the accumulator as set out in the present invention, steam would be generated at such times which could not be used but which would blow off through safety valves.

()ne embodiment of the invention is shown in Fig. 2. In this figure, A represents the internal combustion unit compris ing one or more internal combustion engines in which hydrocarbon fuel is burned in well known manner and from which the burned gases pass through conduits B to the steam generator composed of one or more boilers (3. Means to supply fuel to the internal combustion engines and control thesame is shown diagrammatically by conduits 1'3 and valves 14. From the boilers the steam flows through the conduits D to the conduit E to which an accumulator F, consisting of a tank containing water in which steam con denses, causing the pressure therein to rise, and from which steam may be withdrawn, causing the pressure ,to drop, is connected in parallel. A turbine K is also supplied with steam from conduit E. The turbine drives an electric generator Nand exhausts into a condenser L. Conduit O is connected to conduit E by means of a reducing valve M actuated by the pressure in conduit 0. Steam consumers P take steam from conduit O.

The motors A operate at constant load and consequently deliver a substantially constant quantity of exhaust gases to boilers C. Consequently the steam flow from these boilers through conduits D is practicall constant.

As the steam consumption of the steam consumers connected to conduits E and O is variable there is sometimes a surplus of steam whlch passes to the accumulator, which is then charged.- When the steam consumption is greater than the steam supply, the accumulator vF discharges steam into conduit E. The purpose of reducing valve M is to maintain a constant pressure in conduit O, the valve opening more or less on menace decrease of pressure in conduit 0 and closing more or less on rise of pressure in condult O.

In the arrangement as above described, without any regulating means in the conduits conducting steam from the boilers to the accumulator, the pressure in the boilers will vary in accordance with variations of pressure in the accumulator. Consequently the accumulator must be constructed for the same pressure as exists in the boilers. How ever, as this is often undesirable both because of strength and cost of materials, it is preferable to maintain a constant pressure in the boilers and allow pressure variations only in the accumulator. This is obtained,

as indicated, by inserting a so-called overflow valve H in the connecting conduit between conduit E and boilers C. This valve is so governed by the pressure before the same, which in the instant case is the boiler pressure, that if this pressure rises, the valve opens a corresponding amount, and if the pressure decreases the valve closes a corresponding amount.

Fig. 3 shows an arrangement in which steam generated in the boilers passes through a baclr pressure or non-condensing turbine R to generate power before it passes to the accumulator conduit E. As in the previous modification, a reducing valve M, governed by the pressure in conduit 0, is inserted between accumulator conduit E and conduit U. Steam consumers P take steam from conduit 0. The rate of flow of steam from the boilers C through turbine E is constant. If this rate of flow is equal to the rate of demand, balance is at hand. If more steam is generated than is needed in conduit 0, the ressure rises somewhat in this conduit, causing the reducing valve M to close somewhat and the excess of steam passes to the accumulator to be stored. If, on the other hand, the demand for steam is greater than the supply alforded by generators C, the pressure in conduit 0 drops somewhat and reducin valve M opens somewhat and steam t en flows from the accumulator.

The arrangement shown in Fig. 4 corresponds with that of Fig. 3 except that the turbine 11; this case is an extraction turbine with a high pressure stage R and a low pressure stage S, the latter being directly connected to condenser L. As in the previous modifications, the turbine drives an electric generator N from which power is taken. 1

In this case variations in power load can be equalized by the accumulator. For example, if more power is, needed than what is generated by the steam supplied by boilers C on its passage through high pressure stage R, the speed of the turbine decreases somewhat and speed regulator '1 permits steam to flow from the accumulator to the low pressure section S. If, on the other hand, the speed of the turbine increases because of a decrease in power demand, the regulator T decreases the fiow of steam to 5 the loW pressure stage and the surplus of steam passes to the accumulator line E. Variations in the low pressure line are .equalized by the accumulator in the same manner as explalned with reference to m Fig. 2.

Fig. shows a load chart for a plant in which, for a certain period, there is a given average load and for another period, the average has a' different value. There may be, for example, a certain average value for one day and a different average value for another day. In this figure, abscissa rep resent time and ordinates represent load as was the case in Fig. 1. Variations in load may be divided, in the case represented by Fig. 5, into a main variation, designated by f and into a superposed set of variations of rapid frequency and great amplitude, designated by g. In cases such as this, it is preferable to vary the fuel supply to the internal combustion engines so that they take up a base load, designated by it, while steam motors take up the variations in load according to the curve g. To facilitate this mode of operation, a pressure gage 10 (see Fig. 2)

or other instrument such as a temperature responsive device, indicated at 11, is mounted at the engineers place, designated by 12,

to indicate the state of charge of the accumulator, the engineer then regulating the fuel supply and consequently the power output of the internal combustion engines in accordance with such indicating means. For example, if the load on the plant should decrease as ,indicated at 70, inFig. 5, the accumulator would be'charged and when the state of charge becomes high, that is to say,

when an upper limit of'charge is reached, the engineer either reduces the power output of the internal combustion engines or cuts one or more of them out of service so that they will take up the base load while the steam motors take care of the peak loads. If, on the other hand, the condition of charge of the accumulator approaches a lower limit value, for instance at the moment 7' in Fig. 5, that is to say, if the average load on the plant increases, the engineer must increase the power output of the internal combustion engines or connect more of them into service. In operating the plant in this manner, the internal combustion engines always follow the slow variations, whereas the steam motors tuating curve 9. Since the variations within the curve f take place at intervals comprising days, it will be understood that the load on the internal combustion engines may be considered constant.

6 By this method of operation the accumuoperate in accordance with the rapidly fluc when the pressure in the exhaust gases from the internal combustion unit to a steam generator, leading steam from the steam generator partly to a suitable motor and partly toja steam accumulator,

operating the motor to take care of the varia tions in load above what is taken care of by the internal combustion unit and equalizing the momentary consumption and generation of steam by means of the accumulator.

2. The method of operating a power plant including one or more internal combustion engines, a steam generator comprising one or more boilers, a steam motor unit and a steam accumulator, which consists in converting the energy of combustion of hydrocarbon fuel into mechanical energy in the internal combustion engines, utilizing the heat remaining in the burned gases to gen' erate steam in the steam generator, converting the heat of steam into mechanical energy in the motor unit, leading any surplus of steam generated over the steam consumption of the motor to the accumulator, storing steam in the accumulator, leading steam from the accumulator to the motor unit' when necessary, varying the energy supplied by the internal combustion engines 111 accordance with the upper and lower limits of charge of the accumulator and varying the energy supplied by the motor unit to take care of the remaining load variations on the internal combustion engines and motor unit.

3. The method of operating a power plant including an internal combustion engine a boil r, a steam motor and an accumulator which consists in converting the energy of combustion of hydrocarbon fuel into mechanical energy in the internal combustion engine, utilizing the heat'remainmg in the burned fuel to generate steam, converting the heat of steam into mechanical energy 4. The method of producing power which consists inconverting the energy of a fluid fuel into mechanical energy by combustion, ut lizing the heat remaining in the burned fuel to generate steam, converting heat of the team into mechanical energy, storing steam and varying the COIIVBI'SIOII of the energy of fluid fuel into mechanical energy in accordance with the condition of the stored steam.

5. In a steam plant, an internal combustion engine unit, means to operate said engine unit at substantially uniform load, a boiler, a steam motor unit, an accumulator,

" means to lead exhaust gases from the internal combustion engine unit to the boiler, means to lead steam from the boiler to the accumulator, means to lead steam from the boiler and from the accumulator to the m0- tor unit in momentary quantities serving in addition to the momentary power supply from the internal combustion engine unit to supply the whole plant power load, and

means situated in the vicinity of the internal combustion engine unit to indicate the con dition of charge of the accumulator Whereby the internal combustion engine unit may be controlled.

\ 6. In a steam plant, an internal combustion engine unit, means to operate said unit at substantially uniform load, a steam generator, means to conduct exhaust gases from said internal combustion engine unit to said steam generator, a regenerative accumulator,

means to conduct steam from said generator to said accumulator, consuming means an means to conduct steam from the accumulator to the consuming means to take care of peak loads.

In testimony whereof We afiix our signatures.

JOHANNES auras. nMiL JOSSE.

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