JPH0789739B2 - Combined power generation method including magnetohydrodynamic power generation - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a combined power generation method and a combined power generation system capable of simultaneously driving a closed cycle magnetohydrodynamic power generation device, a gas turbine power generation device, and a steam turbine power generation device.

[Conventional technology]

Magnetohydrodynamic power generation (MHD power generation) is a power generation method in which an electromagnetic gas jet is caused to flow in a magnetic field to generate an electric current.
This electromagnetic gas is high temperature plasma obtained by burning heavy oil or the like, or plasma of a working fluid indirectly heated from a heat source.

Thermodynamic fluid (working fluid) A closed cycle type magnetohydrodynamic power generation system that does not move in and out of a substance but only exchanges heat is generally installed in the magnetohydrodynamic power generator and its upstream side, and operates. It consists of a heater that forms a fluid into a plasma and conduits that circulate them.

A combined power generation system that combines a magnetohydrodynamic power generation cycle, a gas turbine power generation cycle, and / or a steam turbine power generation cycle to effectively utilize heat has been proposed.

[Problems to be solved by the invention]

However, in combined power generation systems that include closed-cycle magnetohydrodynamic power generation that uses fossil fuels such as coal as a heat source to heat the working fluid, it is generally necessary to heat the working fluid to 1500 ° C or higher, and when coal is burned at this temperature, the exhaust gas It contains sulfur oxides, nitrogen oxides, and molten ash, which may damage, damage, or damage downstream equipment and components. Therefore, it is necessary to prevent the corrosion of the combined gas turbine blades and the like, and to carry out gasification desulfurization treatment on the coal in advance in order to protect the environment, and also to install a desulfurization device on the exhaust gas line of the direct combustion exhaust gas of the heat source coal. It has to be installed, requires extra investment and is not economical.

In order to drive this closed cycle magnetohydrodynamic power generation cycle, the exhaust gas burned at high temperature contains nitrogen oxides generated at high temperature, and an expensive high-efficiency denitration device for removing this nitrogen oxides must be installed. I have to.

The present invention has been made based on the above background, and an object of the present invention is to prevent the apparatus from being corroded and to show a high combined power generation efficiency, that is, a combined power generation of a magnetohydrodynamic power generation, a gas turbine and / or a steam turbine power generation. A method and system are provided.

[Means for solving problems]

The above problems can be achieved by the present invention. That is, the combined power generation method including magnetohydrodynamic power generation of the present invention uses the direct combustion exhaust gas of coal as a heat source to heat the first working fluid of the closed cycle magnetohydrodynamic power generation cycle to drive the magnetohydrodynamic power generation cycle to perform the first operation. The coal combustion exhaust gas after heating the fluid is introduced into a fluidized bed boiler containing a desulfurizing fluid medium containing a desulfurizing agent for limestone or / and dolomite, for example, to heat the second working fluid of the steam turbine power generation cycle to generate steam. It is characterized by desulfurizing coal combustion exhaust gas while driving a turbine power generation cycle.

In a preferred embodiment of this invention, the fluidized bed boiler fluid bed temperature is set at about 800 to about 900 ° C.

In a preferred embodiment of the present invention, the coal combustion exhaust gas at the outlet of the fluidized bed boiler is made into a high pressure and high temperature gas, and this high temperature and high pressure exhaust gas is introduced into a gas turbine to drive this turbine.

In another preferred aspect of this invention, the gas pressure in the fluidized bed boiler is substantially equal to the ambient pressure.

In a preferred embodiment of the present invention, a small amount of air is introduced into the fluidized bed boiler to burn unburned carbon content in the exhaust gas,
It is possible to accelerate the absorption of sulfur oxides and the reduction and removal of nitrogen oxides.

[Work]

In the combined power generation method of the present invention, coal is burned at a high temperature, and the coal is directly used to generate the first working fluid of the magnetohydrodynamic power generation cycle.
Heat above 1500 ° C. The heated working fluid circulates to drive and generate electricity in the magnetohydrodynamic power generation cycle.

The coal combustion exhaust gas used for heating the first working fluid has a slightly lowered temperature due to heat exchange, but has a sufficiently high temperature of 800 ° C. or higher. Therefore, the coal combustion exhaust gas entering the fluidized bed boiler operates the fluidized bed boiler at a fluidized bed temperature of about 800 ° C. or higher. At temperatures of about 800-900 ℃,
A desulfurizing agent such as limestone or dolomite in a fluidized medium can fix sulfur oxides in exhaust gas as CaSO ₄ .

Further, at this fluidized bed temperature, if the heat transfer tube of the steam turbine power generation cycle is arranged in the fluidized bed, the second working fluid for steam turbine power generation can be sufficiently heated, and the heated working fluid circulates. To drive and generate a steam turbine power generation cycle.

The coal flue gas used to heat the first working fluid and the second working fluid is also desulfurized and cleaned hot high pressure gas. Therefore, this combustion exhaust gas can be effectively used again and again.

〔Example〕

Hereinafter, the present invention will be described more specifically by way of examples, but the present invention is not limited to the following examples as long as the gist thereof is not exceeded.

FIG. 1 shows a flow chart of an example system that can be used in the power generation method of the present invention.

In the apparatus of this aspect, the coal combustion furnace 1, the heater 2 for the first working fluid provided on the upstream side of the exhaust gas emitted from the coal combustion furnace, and the closed cycle electromagnetic system in which the working fluid is heated by the heater 2 A fluid power generator 3, a fluidized bed boiler 5 provided downstream of the exhaust gas of the heater 2 and filled with a desulfurizing fluid medium 4, and a heat transfer tube 6 provided in the fluidized bed boiler 5.
And a steam turbine power generator 7 in which the second working fluid is heated via the.

The system of this aspect operates as follows.

Air and coal are supplied to the combustion furnace 1 and burned, and the generated high-temperature exhaust gas is introduced into the heater 2. Since it is a closed cycle, only heat exchange is performed in this heater, and the working fluid for magnetohydrodynamic power generation heats a rare gas such as argon or helium to 1500 ° C. or higher to drive the magnetohydrodynamic power generation cycle. The exhaust gas emitted from the heater 2 has a temperature of 800 ° C. or higher, and the gas is introduced into the fluidized-bed boiler 5 from the lower part thereof. The fluidized medium 4 is heated to a fluidized bed temperature of 800 to 900 ° C. which is optimum for desulfurization to fix the sulfur oxides in the exhaust gas to CaSO ₄ , and the second operation of the steam turbine power generation cycle 7 via the heat transfer pipe 6. The fluid is heated to drive this power generation cycle. The coal combustion exhaust gas emitted from the fluidized bed boiler 5 has been cleaned, so that it is released as it is or by a simple process to the outside, and when it can be used as a working fluid for a turbine or the like, this exhaust gas is used for various purposes. Can be used for

FIG. 2 shows a flow chart of another example of the system that can be used in the power generation method of the present invention.

In the system according to this aspect, the coal combustion furnace 1, the heater 2 for the first working fluid provided on the upstream side of the exhaust gas emitted from the coal combustion furnace, and the closed-cycle electromagnetic system in which the working fluid is heated by the heater 2 The fluid power generator 3, the fluidized-bed boiler 5 provided downstream of the exhaust gas of the heater 2 and filled with the desulfurizing fluid medium 4, and the heat transfer pipe 6 provided in the fluidized-bed boiler 5 to form the second working fluid. , A steam turbine power generator 7 for heating the gas turbine, a gas turbine 8 downstream of the exhaust gas of the fluidized bed boiler 5, and an exhaust stack 9 further downstream.
And a compressor 10 that is linked with the gas turbine 8 to compress and supply the air for coal combustion.

The system of this aspect operates as follows.

Coal is burned in a combustion furnace 1 to which compressed air is supplied from a compressor 10, and high-temperature exhaust gas generated is introduced into a heater 2. Since it is a closed cycle, only heat exchange is performed in this heater, and the working fluid for magnetohydrodynamic power generation, for example, a rare gas such as argon or helium is 1500 ° C.
The magnetohydrodynamic power generator 11 is driven by heating above. Heater 2
The exhaust gas emitted from the bottom of the fluidized bed boiler 5 is introduced into it. The fluidized medium 4 is heated to the optimum fluidized bed temperature for desulfurization to fix the sulfur oxides in the exhaust gas to CaSO ₄ , and the second working fluid of the steam turbine power generation cycle 7 is heated via the heat transfer pipe 6. This power generation cycle is driven.
In this mode, since the coal combustion exhaust gas emitted from the fluidized bed boiler 5 has a high pressure of 4 to 20 atm and a high temperature of 400 to 900 ° C., for example, it is introduced into the gas turbine 8 to drive the compressor 10 operating in conjunction with it. To do. Since this exhaust gas has been cleaned, it is discharged from the chimney 9 to the outside as it is.

FIG. 3 shows a flow chart of still another system that can be used in the power generation method of the present invention.

In the apparatus of this aspect, the coal combustion furnace 1, the heater 2 for the first working fluid provided on the upstream side of the exhaust gas emitted from the coal combustion furnace, and the working fluid heated by the heater 2 are driven. Via the system 3 including the magneto-hydrodynamic generator 11, the fluidized bed boiler 5 provided downstream of the exhaust gas of the heater and filled with the desulfurizing fluid medium 4, and the heat transfer tube 6 provided in the fluidized bed boiler 5. A steam turbine power generator 7 for heating the second working fluid, a gas turbine 8 downstream of the exhaust gas of the fluidized bed boiler 5, an economizer 12 and a chimney 9 for exhaust gas further downstream, and a gas turbine 8 A compressor 10 is provided which is linked to and compresses and supplies the air for coal combustion. In this aspect, in addition to these, a heat exchanger for exchanging heat with another steam turbine device 13 downstream of the magnetohydrodynamic generator.
A high temperature gas dust remover 15 is provided between the gas turbine 8 and the outlet of the fluidized bed boiler 5.

The system of this aspect operates similarly to the previous aspects.

Coal is burned in the combustion furnace 1 supplied with compressed air from the compressor 10, and the generated high-temperature exhaust gas is introduced into the heater 2. Working fluid for magneto-hydrodynamic power generation (eg rare gas) 15
The magnetohydrodynamic power generation cycle is driven by heating to over 00 ° C.
The exhaust gas emitted from the heater 2 is introduced into the fluidized-bed boiler 5 from the lower part thereof. The fluid medium 4 is heated to the optimum fluidized bed temperature for desulfurization to remove the sulfur oxides in the exhaust gas from Ca.
The second working fluid of the steam turbine power generation cycle 7 is heated via the heat transfer tube 6 while being fixed to SO ₄ , and this power generation cycle is driven. The coal combustion exhaust gas discharged from the fluidized bed boiler 5 is dedusted by the high temperature gas dedusting device 15, drives the gas turbine 8 and the compressor 10, and is an economizer.
Via 12 to the chimney 9.

In the present invention, various modifications are possible without being limited to the above embodiment. For example, when introducing the exhaust gas after driving the magnetohydrodynamic power generation cycle into the fluidized bed boiler, by adding a small amount of combustion air, combustion of unburned carbon content in the exhaust gas in the fluidized bed, sulfur oxides Absorption of nitrogen oxides and reduction and removal of nitrogen oxides can be promoted. As a result, plant efficiency can be improved by improving combustion efficiency, and denitration equipment can be reduced, thus improving economic efficiency.

〔The invention's effect〕

The present invention having the above configuration and operation has the following effects.

(B) Since the fluidized bed boiler simultaneously recovers heat from the coal combustion exhaust gas after driving the MHD power generation cycle and treats smoke, high combined power generation efficiency can be obtained, and the combined power generation system can be simplified and the equipment can be made compact. Can be realized.

(B) Since the coal combustion exhaust gas from the fluidized bed boiler outlet is the desulfurized cleaning gas, the gas does not cause corrosion or damage to the gas turbine blades. The fluidized bed boiler is a pressurized fluidized bed boiler with a gas pressure of 4 to 20 atm, the exhaust gas at the boiler outlet temperature of 400 to 900 ° C. is introduced into the gas turbine, and the gas turbine compresses and supplies air for coal combustion. Can be driven, and the power consumption of the plant can be reduced. On the other hand, when the exhaust gas temperature is relatively high at 800 to 900 ° C., the gas turbine can be further connected to a generator to generate power, and the plant efficiency is improved.

[Brief description of drawings]

FIG. 1 is a flow diagram of an example combined power generation system that can be used in the method of the present invention, FIG. 2 is a flow diagram of another example combined power generation system, and FIG. 3 is a further example of combined power generation system. FIG. 1 ... Coal combustion furnace, 2 ... Heater, 3 ... Closed magnetohydrodynamic power generation cycle, 4 ... Fluid medium, 5 ... Fluidized bed boiler, 6 ... Heat transfer tube, 7 ... Steam turbine power generation cycle, 8 ...... Gas turbine, 9 ...... Chimney, 10 ...... Compressor, 11 ...... Magnetic fluid generator, 12 ...... Ecomizer,
13 …… Steam turbine cycle, 14 …… Heat exchanger, 15 ……
High temperature gas dust remover.

Claims (6)

[Claims] 1. A direct combustion exhaust gas of coal is used as a heat source to heat a first working fluid of a closed cycle magnetohydrodynamic power generation cycle to drive the magnetohydrodynamic power generation cycle, and the exhaust gas after heating of the first working fluid is heated. , A composite power generation characterized by being introduced into a fluidized bed boiler containing a desulfurizing fluid medium to heat a second working fluid of a steam turbine power generation cycle to drive the steam turbine power generation cycle and desulfurize the exhaust gas. Method. 2. The combined power generation method according to claim 1, wherein the fluid medium contains a desulfurizing agent for limestone and / or dolomite. 3. A fluidized bed boiler having a fluidized bed temperature of 800 to 900 ° C.
The combined power generation method according to claim 1 or 2. 4. The fluidized-bed boiler outlet exhaust gas is high-pressure high-temperature gas, and the high-temperature high-pressure exhaust gas is introduced into a gas turbine to drive the turbine.
The combined power generation method according to item. 5. The combined power generation method according to claim 1, wherein the gas pressure in the fluidized bed boiler is substantially equal to the atmospheric pressure. 6. A small amount of air is introduced into the fluidized bed boiler,
7. The combined power generation method according to any one of items 1 to 5, which promotes combustion of unburned carbon content in exhaust gas, absorption of sulfur oxides, and reduction and removal of nitrogen oxides.