JP2585787B2 - Ammonia treatment unit for power plant - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power plant, and more particularly to an ammonia processing apparatus in a power plant using a simple substance of ammonia or a mixture containing ammonia as a working fluid.

2. Description of the Related Art In a power plant using ammonia alone or a mixture containing ammonia as a working fluid, a condenser is provided at an outlet of a steam turbine, and turbine exhaust steam is condensed by the condenser. The condensate is sent to a boiler or the like by a condensate pump and heated. The steam turbine is driven by the generated high-temperature and high-pressure ammonia / steam, and a generator is operated to obtain electricity.

Thus, in a power plant using such ammonia alone or a mixture containing ammonia as a working fluid, similarly to a power plant using ordinary steam as a working fluid, a non-condensable gas (external system) is provided at a condenser at a turbine outlet. It is indispensable to secure the turbine performance by extracting more mixed gas or partly decomposing the working fluid, thereby preventing the internal pressure of the condenser from rising.

Then, in the extraction of the non-condensable gas, a part of the working fluid is extracted together with the non-condensable gas, but since the ammonia gas in the extracted gas cannot be released to the atmosphere as it is due to pollution, A device that treats ammonia gas without pollution is required. Therefore, conventionally, a dedicated treatment device for making the extracted ammonia gas pollution-free is specially installed.

On the other hand, a denitration device for removing NOx in combustion gas generated by combustion of fossil fuel or the like in a boiler or the like is generally provided in the middle of a flue.

As an example of a denitration apparatus, one using ammonia as a reducing agent is known, and a method as shown in FIG. 2 is conventionally used to supply ammonia to this denitration apparatus.

That is, in FIG. 2, 1 indicates a denitration apparatus for denitrifying the combustion gas 2 using ammonia as a reducing agent,
It comprises an ammonia injection nozzle 3 and a denitration reaction section 4.

Then, the ammonia for denitration is stored in the liquid ammonia tank 5. The liquid ammonia 6 in the tank 5 is led to a vaporizer 7. In the vaporizer 7, the liquid ammonia 6 is heated and vaporized by steam 8 obtained by using a combustion gas generated by the combustion of fossil fuel or the like in a boiler or the like as a heat source, and the ammonia gas produced thereby is supplied to an accumulator 9. Once stored. The ammonia gas 10 stored in the accumulator 9 is then mixed with the dilution air 13 sent through the damper 11 and the fan 12, and then mixed with the NOx-containing combustion gas 2 from the ammonia injection nozzle 3 of the denitration device 1. Is blown into As a result, the combustion gas 2 is denitrified in the denitration reaction section 4 and then discharged from the chimney 14 to the atmosphere.

In FIG. 2, reference numeral 15 denotes a steam control valve, 16 denotes hot water, and 17 denotes an ammonia gas control valve.

Problems to be Solved by the Invention As described above, in a conventional power plant using a working fluid of ammonia alone or a mixture containing ammonia, a non-condensable gas is extracted together with a non-condensable gas from a condenser for condensing turbine exhaust steam. Since a dedicated device for detoxifying ammonia gas is specially installed, the system configuration is complicated and the equipment cost is high.

In the denitration of the combustion gas, the conventional ammonia supply method as shown in FIG. 2, that is, the method of supplying the ammonia gas generated by evaporating the liquid ammonia by the vaporizer, involves the installation of the vaporizer. This raises the cost and lowers the performance of the power plant due to the use of expensive steam produced using fossil fuel or the like as a heat source for heating liquid ammonia.

Means for Solving the Problems In order to solve the problems of the prior art, the present invention provides a method for extracting a turbine exhaust vapor into a condenser in a power plant using a single ammonia or a mixture containing ammonia as a working fluid. A trachea is attached, and a denitration device using ammonia as a reducing agent is connected to the bleed tube via a conduit.

According to such a means, in a power plant using ammonia alone or a mixture containing ammonia as a working fluid, ammonia gas in a working fluid directly heated by a boiler or the like using fossil fuel or the like as a heat source is supplied from a condenser to an uncondensable gas. And the extracted ammonia gas can be effectively used as a reducing agent for a denitration apparatus.

Embodiment An embodiment of the present invention will be described below in detail with reference to FIG. In FIG. 1, the same parts as those shown in FIG. 2 are denoted by the same reference numerals.

Reference numeral 21 denotes a working fluid composed of ammonia alone or a mixture containing ammonia. This working fluid 21 is heated by a boiler or the like (not shown), becomes high-temperature and high-pressure ammonia / steam, flows into a steam turbine 22, and
22 is driven, whereby the generator 23 is operated, and electricity is obtained.

The turbine exhaust steam 24 from the steam turbine 22
Flows into the condenser 25 provided at the turbine outlet,
In the heat transfer section 26, the water is cooled by cooling water (seawater) 27 and condensed. This condensate 28 is then drained into the sump 29 of the condenser 25
Thereafter, the condensate is sent to a boiler (not shown) by the condensate pump 30 and is heated again.

Thus, according to the present invention, the bleed pipe 31 is attached to the space between the heat transfer section 26 and the liquid reservoir 29 in the condenser 25 for condensing the turbine exhaust steam 24, and the bleed pipe 31 is attached to the denitration device 1 Is connected via a conduit 32 to the ammonia injection nozzle 3. An extraction gas control valve 33 is provided in the middle of the conduit 32.

 Next, the operation will be described.

Turbine exhaust steam 24 from steam turbine 22 is supplied to condenser 25
The non-condensable gas (ie, hydrogen and nitrogen gas generated by decomposition of ammonia in a high-temperature portion such as a boiler) and the ammonia gas
The fuel gas is extracted from the condenser 25 and then mixed with the dilution air 13 sent through the damper 11 and the fan 12 on the way of flowing through the conduit 32, and then the combustion gas 2 containing NOx is supplied from the ammonia injection nozzle 3 of the denitration device 1. It is blown in. As a result, the combustion gas 2 is denitrated in the denitration reaction section 4 and thereafter discharged from the chimney 14 to the atmosphere.

The control valve 33 provided in the middle of the conduit 32 controls the amount of extracted gas, thereby controlling the amount of ammonia gas for denitration.

Effect of the Invention As described above, according to the present invention, in a power plant using ammonia alone or a mixture containing ammonia as a working fluid, ammonia extracted together with a non-condensable gas from a condenser for condensing turbine exhaust steam is used. Since the gas is used as a reducing agent in the denitration equipment, there is no need to install equipment for the decontamination treatment required when the ammonia gas extracted from the condenser is directly released to the atmosphere. Become.

In addition, when a part of the extracted ammonia gas is used as a reducing agent of a denitration device, it is necessary to install a device for detoxifying other ammonia gas. Can be smaller.

According to the present invention, it is not necessary to install a vaporizer for generating ammonia gas from liquid ammonia,
Therefore, a heat source such as steam in the vaporizer is not required.

[Brief description of the drawings]

FIG. 1 is a system diagram showing an example of an ammonia treatment device of a power plant according to the present invention, and FIG. 2 is a system diagram showing a conventional method for supplying ammonia to a denitration device. DESCRIPTION OF SYMBOLS 1 ... Denitration apparatus, 2 ... Combustion gas, 3 ... Ammonia injection nozzle, 4 ... Denitration reaction section, 5 ... Liquid ammonia tank, 6 ... Liquid ammonia, 7 ... Vaporizer, 8 ... Heating Steam, 9 accumulator, 10 ammonia gas for denitration, 11 damper, 12 fan, 13 air for dilution, 14 chimney, 15 steam control valve, 16 hot water, 17 …… Ammonia gas control valve, 21 …… Working fluid, 22
... steam turbine, 23 ... generator, 24 ... turbine exhaust steam, 25 ... condenser, 26 ... heat transfer section, 27 ... cooling water, 28
... condensate, 29 ... liquid reservoir, 30 ... condensate pump, 31 ... bleed pipe, 32 ... conduit, 33 ... extraction gas control valve.

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Masatoshi Kurume 2-5-1 Marunouchi, Chiyoda-ku, Tokyo Inside Mitsubishi Heavy Industries, Ltd. (72) Inventor Isamu 2-5-1 Marunouchi, Chiyoda-ku, Tokyo Mitsubishi Heavy Industries (72) Inventor Masahiro Soda 1-1, Akunoura-cho, Nagasaki City, Nagasaki Prefecture Mitsubishi Heavy Industries, Ltd. Inside Nagasaki Research Laboratory (72) Inventor Yasushi Mori 1-1, Akunoura-cho, Nagasaki City, Nagasaki Prefecture Mitsubishi Heavy Industries, Ltd. Inside Nagasaki Research Institute (72) Inventor Sanae Kawazoe 1-1, Akunouramachi, Nagasaki City, Nagasaki Prefecture Mitsubishi Heavy Industries, Ltd. Nagasaki Research Institute Co., Ltd. (56) References JP-A-60-150404 (JP, A) JP-A-59-2770 (JP, B1)

Claims (1)

(57) [Claims] In a power plant that uses ammonia alone or a mixture containing ammonia as a working fluid, a bleed pipe is attached to a condenser for condensing turbine exhaust steam, and a denitration device using ammonia as a reducing agent is connected to the bleed pipe by a conduit. An ammonia treatment device for a power plant, wherein the ammonia treatment device is connected via a power source.