JPS6022167B2 - two-fluid power station - Google Patents

Description

[Detailed Description of the Invention] This invention provides an auxiliary power unit using expansion gas in addition to the main power unit in order to improve the thermal efficiency of a power station that uses liquefied gas such as LPG as fuel in a steam power station or the like. The present invention relates to a two-fluid power station designed to operate, and in particular, to a two-fluid power station designed to utilize waste heat energy of the main driving part to promote improvement in the thermal efficiency of the entire power station.

BACKGROUND ART In the past, liquefied gas has been used as fuel in power stations such as power plants having steam turbine engines in order to deal with resource problems and pollution problems such as air pollution.

- However, in the evaporation of the liquefied gas and in the combustion path, firstly, heat is inevitably lost by the cooled fluid in the evaporator, and from the combustion and post-combustion exhaust processes. There is considerable heat loss due to heat dissipated in the exhaust gas, and this has the inherent drawback that the power plant has extremely poor thermal efficiency.

On the other hand, conventionally, liquefied gas as a fuel is generally passed through a passage through an evaporator, etc., and is evaporated by exchanging heat with natural heat therebetween, and then combusted in a furnace as a gas fuel.

As described above, conventional power plants have disadvantages in that the evaporation equipment is installed separately from the power plant, which makes the plant complex, makes maintenance difficult, and increases equipment and operating costs.

Furthermore, the high exhaust gas temperature raises the atmospheric temperature near the plant, causing changes in the local weather and causing pollution problems such as deterioration of the living environment. The purpose of the present invention is to solve the problems of the power station based on the prior art described above, and to utilize the heat loss of the conventional power station by passing the liquefied gas through a passage that is directly interposed in the prime mover. It is an object of the present invention to provide an excellent two-fluid power station in which the thermal efficiency of the entire power station is improved by operating an auxiliary drive unit in a coordinated manner with respect to the main drive unit which performs vaporization and operates constantly.

The structure of the present invention in accordance with the above object is to supply liquefied gas to a closed cycle driving part, to exchange heat in the condenser of the closed cycle driving part, or in the condenser and exhaust part to gasify the gas, and to convert the gas into an open cycle. In order to improve the actual thermal efficiency of the prime mover, the gas is constantly combusted next to the closed cycle prime mover, allowing the main prime mover to operate at all times and deliver output, and in some cases, some of the gasified liquefied gas is Alternatively, the entire gasified liquefied gas is fed as a working fluid to the pond-installed open cycle driving section, the auxiliary driving section is operated, and the latter is combusted in the closed cycle driving section. If the heat absorbed by the condenser of the cycle drive unit is insufficient, the adjustment mechanism installed in the detour passage closes the gas route to the open cycle drive unit and operates only the closed cycle drive unit, reducing heat loss in the entire drive station. The main idea is to reduce this as much as possible to enable efficient operation.

Next, embodiments of the present invention will be described below based on the drawings.

1 is a liquefied gas tank for liquefied fuel such as LPG, LNG, etc., and the liquefied gas tank 1 is connected to a liquid supply pump 3 through a liquid supply pipe 2, and the liquid supply pump 3 is connected to the next liquid supply pipe 4 through a liquid supply pipe 4. They are connected through a condenser 6 of a closed cycle drive unit 5 as the main drive unit.

The closed cycle driving unit 5 has a boiler 9 facing a furnace 8 having an exhaust gas chimney 7, and a steam turbine 10 is connected to a generator 11. The class 6 condenser is connected to the water supply pump 12 by a closed passage pipe 13 connected in series. The liquid supply pipe 4 connected to the condenser 6 is connected to the condenser 6 and then connected as a gasification pipe 14 to a gas boiler 15 installed inside the chimney 7. The return gas supply pipe 16 communicates with the burner 9 facing into the furnace 8 via a valve 17 and a pressure regulating valve 18.

On the other hand, an open cycle driving unit 20 as an auxiliary driving unit is interposed in the gas supply pipe 16, and a generator 22 is connected to the gas expansion turbine 21.
The branch pipe 23 of the gas passage 1 is inserted and connected to the front part of the valve 17 and the pressure regulating valve 18 of the gas supply pipe 16 of the open cycle driving section 5, and a valve 24 is connected to the inlet of the gas expansion turbine 21. It is provided. In the above configuration, after an appropriate initial operating state, one of the valves 17 and 24 is fully closed and the other is fully open, or each is opened to an appropriate opening degree, and the pressure regulating valve 18 is adjusted to a predetermined pressure. Then, when the burner 9 is ignited and the liquid supply pump 3 is operated, LPG and LN are discharged from the liquefied gas tank.
The liquefied gas of G enters the condenser 6 of the closed cycle driving unit 5 from the liquid supply pipe 4 by the liquid supply pump 3, and exchanges heat with the steam from the steam turbine 10 in the condenser 6, so that at least a portion of the gas is The gas is vaporized and gasified, and passes through the gasification pipe 14 to the gas boiler 15 in the chimney 7, where it is again heat exchanged with the heat of the exhaust gas, completely gasified, and enthalpy is increased, and then sent to the gas supply pipe 16. Then, it flows directly into the burner 19 side or the gas expansion turbine 21 side via the valve 17 or 24, or flows directly into the burner 19 or gas expansion turbine 21 side with an appropriate flow rate distribution, and finally either. The flow rate also passes through the pressure regulating valve 18 and is ignited by the burner 19, combusts in the furnace 8, and heats the boiler 9.

Thus, the steam heated and generated by the boiler 9 is passed through the closed passage pipe 13.
The steam turbine 10 is operated to constantly operate the generator 11, and as before, the condenser 6 exchanges heat with the liquefied gas, and the gas is heated and the exhaust gas is converted to condensed water. It returns to the boiler 9, operates in a closed cycle, and maintains the operation of the main driving unit 5.

On the other hand, the gas flowing from the gas supply pipe 16 through the valve 24 enters the expansion turbine 21 as a working fluid, drives it, operates the generator 22, operates the open cycle driving section 20, and after the operation is completed, Gas is supplied from the branch gas pipe 23 to the gas supply pipe 1
6 and is connected to the burner 9 from the pressure regulating valve 18 as described above.
It is ignited and burned in the furnace 8.

In the above operation, if the load on the closed cycle driving section 5 is small, the amount of heat absorbed by the (liquefied) gas in the condenser 6 and the gas boiler 15 will be small, and in such a state, Then, the valve 17 is fully opened, and the valve 24 is fully closed to stop the open cycle driving unit 20, and only the closed cycle driving unit 5 is operated centrally to vaporize the gas and operate the steam turbine 10 and generator 11. The improvement in heat rate is shown in the figure.

On the other hand, if the amount of heat absorbed by the (liquefied) gas is large, the gas supply pump 21 is driven at high output as much as possible, and furthermore, if necessary, some parts are driven to the gas expansion turbine 21 side and some parts to the burner 19 side. It is also possible to divide the flow into two sides.

In the embodiment shown in FIG. 1, the liquefied gas gasification heat exchange section is a series type in which the gas boiler 15 is installed in the condenser 6 and the exhaust section 7 at the subsequent stage, but the equipment arrangement is designed to be in the reverse order. Of course, this can be done in accordance with the system design.

In addition, for a power station designed to generate very little heat from the exhaust gas from the furnace 8, the gas boiler 15 in the exhaust section 7 is omitted as shown in Figure 2, and the entire amount of gas is vaporized only by the condenser 6. I'll do it like that.

As described above, according to the present invention, in a power station that uses liquefied gas as fuel, the closed cycle driving section is used as the normally operating main driving section,
By providing the liquefied gas vaporization heat exchange mechanism to the condenser and exhaust section of the closed cycle driving section, or only to the condenser,
The system's scarlet heat can be used effectively, and the plant as a whole can achieve an extremely high power plant thermal efficiency.As the steam power plant cools the condenser with low-temperature gas, it has the effect of improving the actual thermal efficiency. By making heat exchange equal to heat exchanger, the efficiency of the heat transfer surface can be improved by collecting the heat contained in the exhaust gas, and since a separate evaporator is not required, gas can be evaporated immediately, and the equipment, There are advantages in terms of costs.

In particular, a main gas passage opening/closing valve and an auxiliary prime mover gas passage opening/closing valve are installed at the branch point between the main gas passage and the gas passage of the auxiliary driving unit, so each valve can be opened or closed according to changes in the load of the closed cycle driving unit. Adjustments can be made to change the gas flow distribution. Therefore, when the output of the open cycle drive section is low, the bypass to the open cycle drive section is stopped and only the main drive section is operated efficiently.Also, when the output of the closed cycle drive section is sufficiently high, the open cycle drive section By bypassing the gas to the auxiliary generator, power can be recovered by the auxiliary generator, and efficient operation can be achieved in this case as well. By switching the valve, the output of the generator can be kept at the highest efficiency at all times.

Furthermore, even if the auxiliary drive unit needs to be stopped for inspection or the like, the main drive unit can continue to operate, which has an extremely large operational advantage.

[Brief explanation of the drawing]

The drawings show an embodiment of the invention, and FIG.
FIG. 2 is an explanatory diagram of another embodiment. 10...Steam turbine, 5...'Closed cycle driving unit, 21...Gas expansion turbine, 20
...... Open cycle driving part, 1... Liquefied gas tank, 4, 14, 16... Main gas passage, 6.
...Condenser, 9...Boiler, 19...
... Burner, 23... Gas passage of auxiliary drive unit, 17... Main gas passage on-off valve, 24... Auxiliary drive unit gas circuit on-off valve, 7... Exhaust Department. Figure 1 Figure 2

Claims (1)

[Claims] 1. A steam turbine that operates a main generator, a boiler, and a feed water pump are connected by a closed passage pipe to form a closed cycle driving part, and a tank for liquefied gas used as fuel is A connected and extending liquid supply pipe is connected to a burner that heats the boiler as a gas supply pipe through a heat exchange section with the closed passage pipe of the closed cycle driving unit, and the supply gas pipe In a two-fluid power plant in which a gas expansion turbine for operating an auxiliary generator is installed in a stage before being connected to a burner, the gas supply pipe is directly connected to the burner via a valve, and the valve is connected to the burner. A bypass valve is provided at the front stage of the closed cycle driving section to recover the output by bypassing the high enthalpy gas to the gas expansion turbine when the output of the closed cycle driving section is large. A two-fluid power station characterized in that the two-fluid power station is combined with a gas supply pipe directly connected to a valve and connected to a burner to form an open cycle driving unit. 2 The steam turbine that operates the main generator, the boiler, and the feed water pump are connected by a closed passage pipe to form a closed cycle driving section, which is connected to and extends to a tank for liquefied gas used as fuel. The liquid supply pipe is connected to the burner that heats the boiler as a gas supply pipe through a heat exchange part with the closed passage pipe of the closed cycle driving part and a heat exchange part of the boiler exhaust part, and is connected to the burner that heats the boiler as a gas supply pipe. In a two-fluid power plant that has a gas expansion turbine that operates an auxiliary generator interposed before the gas supply pipe is connected to the burner, the gas supply pipe is directly connected to the burner via a valve. In addition, a bypass valve is provided upstream of the valve to recover the output by bypassing the high enthalpy gas to the gas expansion turbine when the output of the closed cycle driving section is large. A two-fluid power station characterized in that a branched gas from the valve is connected to a gas supply pipe directly piped from the valve and connected to a burner to form an open cycle driving unit.