JPH07158411A - Power plant - Google Patents

Abstract

(57) [Summary] [Structure] Condensation that combusts hydrogen and oxygen and mixes water vapor, a turbine driven by the water vapor, and exhausted water vapor that is condensed by direct contact with cooling water. Power plant consisting of a reactor, a pump that boosts the pressure of condensed water, and a generator driven by a turbine. [Effect] The pressure ratio of the turbine can be set to a value not so different from that of the current gas turbine, and the difficulty of blade design can be alleviated. Further, since the pressurization is performed with the liquid, the work required for the pressurization is small, and it is possible to obtain the comparatively high-temperature warm wastewater of about 100 ° C. that has a high utility value as the hot wastewater.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power plant that uses hydrogen as a fuel and oxygen as an oxidant to combust, and uses steam generated thereby as a working fluid to drive a turbine to generate electricity.

[0002]

2. Description of the Related Art When hydrogen is completely combusted with oxygen, only steam is generated, and it does not generate carbon dioxide or other harmful substances, which are often talked about as a global environmental problem in recent years. Since hydrogen has a large amount of heat generated per unit weight when burned, it has the characteristic that it can easily generate a high temperature, and is a fuel that should be noted from the viewpoint of improving plant efficiency in a power plant. Techniques relating to turbines using this hydrogen are described in, for example, JP-A-63-32110 and JP-A-4-66703. FIG. 2 is an example of a power plant using hydrogen according to Japanese Patent Laid-Open No. 63-32110, in which hydrogen and oxygen are supplied to a combustor 1 and burned, and steam is mixed into the combustor 1 to keep a predetermined temperature. The steam whose pressure has been adjusted flows into the turbine 2, and the generator 3 is driven. Then, the steam discharged from the turbine flows into the condenser 8 and is condensed, and a part of the water is pressurized through the water supply pump 5 and supplied to the above-described combustor 1 by the water supply injection device 9. Has become. Such a power plant is different from the method of generating steam through a heat transfer tube of a boiler, which is used in a normal thermal power plant, because steam can be directly generated by combustion, so it is easy to obtain high-temperature steam. Therefore, there is a possibility that the thermal efficiency of the plant can be significantly improved.

Further, as disclosed in Japanese Patent Application Laid-Open No. 4-66703, the steam generated by the combustion of hydrogen and oxygen is used as steam and condensed to carry away the heat energy to the cooling water of the condenser. There is a system to eliminate loss and achieve high plant efficiency.

[0004]

In the turbine by hydrogen combustion according to Japanese Patent Laid-Open No. 63-32110, the steam passing through the turbine is finally condensed in the condenser to be water, and therefore the turbine outlet The pressure becomes a vacuum below atmospheric pressure,
The pressure ratio between the turbine inlet and outlet becomes extremely large. Further, since steam has a large specific heat, the number of blade stages when designing a turbine increases even if the pressure ratio is the same as that of other working fluids. Therefore, the turbine blade design becomes extremely complicated.

On the other hand, in the power plant according to Japanese Unexamined Patent Publication No. 4-66703, the steam leaving the turbine is not condensed but is pressurized as it is by the compressor and sent to the combustor.
Compared with the method of applying pressure in the state of water, the method of applying pressure in the state of water vapor has a problem in that the work amount in the case of pressurization is large and it is disadvantageous efficiently.

An object of the present invention is to solve the above problems of the prior art, and it is an object of the present invention to provide a hydrogen combustion power generation plant capable of achieving high efficiency even when the pressure ratio of the turbine is small. .

[0007]

To solve the above-mentioned problems, a power plant according to the present invention is driven by a combustor in which hydrogen and oxygen are burned and steam is mixed, and steam from the combustor. A turbine and a condenser that guides water vapor exhausted from this turbine into water to condense it,
The pump includes a pump that boosts the pressure of the condensed water and a generator that is driven by the turbine. Further, at least one stage heat recovery device for raising the temperature of the condensed water may be provided in the downstream of the turbine, and further oxygen and hydrogen supplied to the combustor may be heated by the heat recovery device.

[0008]

The operation of the present invention will be described below. When normal temperature cooling water is used in a normal condenser, the saturated pressure of steam corresponding to the cooling water temperature in the condenser, for example, from 5 kPa to 1
In contrast to the vacuum of about 0 kPa, it is easy to set the pressure inside the condenser to a value around atmospheric pressure (100 kPa) by using the condenser according to the above means. Since the exhaust pressure of the turbine is almost equal to the pressure in the condenser or the condenser, for example, considering the case where the pressure in the combustor is 2 MPa, the pressure ratio between the inlet and the outlet of the turbine when the condenser is used is 20 which is not so different from a normal gas turbine. However, when a normal condenser is used, this pressure ratio is such that the turbine exhaust pressure is 10
In the case of kPa, it becomes 200, and in the case of 5 kPa, it becomes 400, and the design of the turbine blade is considerably different from that of a normal gas turbine. In the case of a steam turbine, the pressure ratio may be a large value exceeding 4000, but the temperature of steam is less than 600 ° C, and the temperature of steam obtained by burning hydrogen is, for example, 1300 ° C. Considering the above, it is appropriate to consider the gas turbine, which is used at a higher temperature than the steam turbine, as a reference.

The condenser considered in the present invention is of a type in which water vapor is introduced into water to be directly condensed, the thermal resistance at the time of condensation is small, and latent heat associated with the condensation is released in the condenser. Maintaining the water temperature in the condenser above 100 ° C. is not so difficult. Since the entire large volume in the condenser has a substantially uniform temperature, even if cooling water at room temperature is flowed into this condenser, it is immediately averaged,
For example, it can be maintained at a predetermined temperature such as 100 ° C. The temperature in the condenser is determined by the heat balance between the inflow and outflow flow rates of cooling water and steam, and the water temperature in the condenser can be set arbitrarily by adjusting the cooling water flow rate. In order to set the pressure ratio of the turbine to a value that is not so different from that of a normal gas turbine, it is important that the temperature inside the condenser can be set to a value exceeding 100 ° C., and the condenser considered in the present invention is Is possible.

When considering a closed cycle using a turbine, the fluid expanded in the turbine needs to be boosted somewhere. In the present invention, this pressurization is performed in the state of water. Compared to gas such as water vapor, water can be regarded as almost incompressible fluid, the pressurizing work expressed as the product of pressure and volume change is small, and pressurizing in the state of water is energy efficient. Is excellent in principle. However, on the other hand, it is necessary to condense the vapor once in order to handle it as a liquid, and the condensation latent heat is discarded to the cooling water side during the condensation, resulting in heat loss. Is the disadvantage of doing. In the present invention, pressurization is performed in the state of water, and the press work is reduced to improve the plant efficiency. Note that the thermal energy carried away by the cooling water during condensation is the saturation temperature of water at atmospheric pressure (100
The temperature is set to a value around ℃) and set to a temperature that is easy to use when using this cooling water as heat. Alternatively, this cooling water can be used for power generation as a heat source on the high temperature side.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be described below with reference to FIG. The combustor 1 is supplied with hydrogen supplied from the hydrogen supply device 11 and a mixture of oxygen and water vapor and burns,
The temperature and pressure are adjusted by the mixing amount of this steam. The steam generated in the combustor 1 is introduced into the turbine 2 and drives the generator 3 to generate electricity. Then, the steam discharged from the turbine 2 is guided to the condenser 4 and condensed in the water in the condenser. The temperature in the condenser at this time can be set to a temperature of 100 ° C. to 110 ° C., for example, and the exhaust pressure of the turbine becomes substantially equal to the saturated vapor pressure at this temperature. The water goes via the condenser to the pump 5, where it is pressurized. The water whose pressure has been increased by the pump 5 is heated by the heat exchanger 7 and becomes steam. Oxygen supplied from the oxygen-steam mixing device 12 is mixed with this steam, and the mixed gas of steam and oxygen is superheated while passing through the superheater 6 to reach a high temperature and supplied to the combustor 1. In the condenser 4,
Cooling water at a flow rate necessary to condense the steam generated by combustion is injected from the cooling water inlet 41, and the sum of the inflowing cooling water amount and the condensed vapor amount flows out from the cooling water outlet 42. The temperature at this time can be set to a relatively high value of 100 ° C. to 110 ° C., for example.

A second embodiment of the present invention is shown in FIG. Figure 1
The difference from the above embodiment is that oxygen is directly supplied to the combustor without being mixed with steam, and steam is supplied to the combustor separately from them.

A third embodiment of the present invention is shown in FIG. Figure 1
The difference from the embodiment described above is that the high-temperature cooling water flowing out from the cooling-water outlet 42 of the condenser 4 is not used as heat but is used as heat energy for power generation.
Via turbine 2, generator 3, condenser 8, pump 5
This is the point that constitutes a loop consisting of.

[0014]

According to the present invention, in a turbine plant that burns hydrogen and oxygen, the pressure of steam discharged from the turbine can be freely set before and after the atmospheric pressure, and the pressure ratio of the turbine is the same as that of the current gas turbine. The values can be set to be not so different, and the difficulty of turbine blade design can be alleviated. Further, since the pressurization is performed in the liquid state, the work required for the pressurization is small, and it is possible to obtain the comparatively high-temperature hot wastewater of about 100 ° C. that has a high utility value as the hot wastewater.

[Brief description of drawings]

FIG. 1 is a system diagram of an embodiment of the present invention.

FIG. 2 is a system diagram of a conventional example of a hydrogen combustion type turbine power plant.

FIG. 3 is a system diagram of a second embodiment of the present invention.

FIG. 4 is a system diagram of a third embodiment of the present invention.

[Explanation of symbols]

1 ... Combustor, 2 ... Turbine, 3 ... Generator, 4 ... Condenser,
5 ... Booster pump, 11 ... Hydrogen supply device, 12 ... Oxygen-steam mixing device, 41 ... Cooling water inlet, 42 ... Cooling water outlet.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Harumi Wakana 7-2-1 Omika-cho, Hitachi-shi, Ibaraki Hitachi Ltd. Energy Research Laboratory

Claims (3)

[Claims] 1. A combustor in which hydrogen and oxygen are burned to mix water vapor, a turbine driven by the water vapor from the combustor, and a condenser for guiding the water vapor exhausted from the turbine into water to condense it. And a pump for increasing the pressure of condensed water, and a generator driven by the turbine. 2. A power generation plant according to claim 1, comprising at least one stage heat recovery device for raising the temperature of at least one kind of fluid of condensed water, oxygen and hydrogen in the wake of the turbine. 3. The power plant according to claim 1 or 2, wherein oxygen is mixed with steam and supplied to the combustor.