RS51511B - THERMAL POWER PLANT - Google Patents

Abstract

Thermal power plant (1), consisting of at least one steam turbine (3) and one heated steam generator (5), characterized in that one combustion device (7) is arranged in the direction (9) of water flow (17) after of the first stage (11) of the turbine, and before the second stage (13) of the steam turbine (3). The application contains 1 more independent and 3 dependent patent claims.

Description

The invention relates to a thermal power plant with at least one steam turbine and one steam generator, which is heated by combustion.

Technical field

In modern thermal power plants, the driving steam for the steam turbine, which is produced most often in a steam generator heated by combustion, where the energy of the hot flue gases is given off in one or more heat exchangers, in which there is water, so that by heating this water, driving steam is created, or they already contain steam, so that the steam is superheated using the said heat exchanger; this kind of superheating of water vapor is carried out in known steam turbines, for example between the high pressure stage and the medium pressure stage of the steam turbine, whereby the water vapor leaving the high pressure stage is superheated in the steam generator by means of a surface intermediate heater located in the steam generator and brought to the medium pressure steam stage of the turbine.

Such intermediate heating of the steam leads, for example, to a high degree of utilization of the steam turbine.

According to the international classification, the invention is marked with MKP F01K 21/04, 7/16.

State of the art

According to the current state of the art in known thermal power plants, the supply of heat energy for the production and/or intermediate superheating of water vapor is achieved by means of heat exchangers through its heating surfaces, which are placed in the steam generator, which is heated by combustion, for example by burning coal, fuel oil or biomass or in general by heating the steam generator with fossil nuclear fuels and where the heating surfaces of the steam generator are brought into contact with hot diiric gases. The very heated surfaces of the heat exchanger give their thermal energy back to water and/or steam, which are conducted inside the body of the heat exchanger formed by the heating surfaces. It means that overheating is achieved by heat transfer from hot flue gases to the surfaces of the heat exchanger and from the surfaces of the heat exchanger to the medium to be heated.

For example, in document US-A-956 937, a thermal power plant has already been presented, which has three steam turbines (13, 14, 17) and one gas generator, which generates working gas with a high proportion of water vapor. With it, for example, a regenerator (93) and/or a gas generator (200) can be combined with one heated steam generator, in order to produce the desired parameters and amount of steam. Further, the document describes the combustion chamber (62,63) between the first and second, that is, the second and third stages of the steam turbine (13, 14, 17), where the flow of water vapor is heated by mixing with the hot gas produced in the combustion chamber.

WO 03/069132 A presents a similar thermal power plant, which has turbines driven by a mixture of water vapor and combustion products.

Technical problem

In the case of known heat exchangers according to the existing state of the art, which are used in the steam generators of known thermal power plants, which transfer the energy of hot flue gases to the medium, which needs to be heated using the materials from which the heating surfaces of the heat exchanger heated by hot flue gases are built, the amount of energy that can be transferred to the medium, which is heated, for example, water and/or steam, is limited by the characteristics of the material of the heating surfaces of the heat exchanger.

For this reason, in known thermal power plants, the permitted steam temperatures are limited, because the surfaces of the heat exchanger, to which the amount of energy is transferred, due to the characteristics of the material and the thermal load limit, which is related to this, cannot be heated more than allowed if desired.

Furthermore, the transfer of heat from the hot flue gases to the medium, which needs to be heated, is burdened with a certain delay, which is caused essentially by the required speed of heating the heating surfaces of the heat exchanger.

Task

The task of the invention is basically to realize a thermal power plant with at least one steam turbine and one steam generator, which can be applied flexibly and which will particularly successfully overcome the indicated defects from the existing state of the art.

Invention presentation

This task according to the invention is solved by a thermal power plant, which consists of at least one steam turbine and one steam generator heated by combustion, where a combustion chamber is placed in the direction of the flow of water vapor after the first stage of the steam turbine and before the second stage of the steam turbine and that the flow of water vapor in the combustion chamber is heated by mixing with the hot flue gas generated in the combustion chamber.

The invention is based on the fact that the heat transfer from the hot flue gas to the heated medium is less limited compared to the existing state of the art, when the heat transfer to the heated medium is performed without the mediation of the heating surfaces of the heat exchanger.

This is achieved in the invention by the fact that the water vapor to be heated is introduced directly into the combustion chamber and that it mixes there directly with the hot methane gas.

This internal additional combustion according to the invention can be applied after the steam generator and before the steam turbine, in the direction of the water vapor flow, so already for superheating of fresh steam or also for superheating of steam, which has already released a part of its energy in one stage of the steam turbine and which, after being superheated according to the invention, is fed to another stage of the steam turbine.

Using the thermal power plant according to the invention, higher water vapor temperatures can be achieved compared to the temperatures according to the existing state of the art, which can then contribute

increasing the degree of usefulness of the thermal power plant.

If the thermal power plant, in which additional combustion is achieved using the combustion chamber according to the invention, is switched off or the combustion chamber fails, then the thermal power plant can continue to work like known thermal power plants.

It is advantageous to feed hydrogen and/or hydrocarbon, especially methane, as fuel into the combustion chamber.

It is especially recommended that the fuel contains carbon and/or hydrogen.

Thanks to the application of hydrogen as a fuel, the first advantage is that — in the case that the hydrogen is produced as usual by reforming or gasification of one hydrocarbon — the aggressive carbon dioxide obtained is retained already during the production of hydrogen by reforming or gasification of one hydrocarbon with a small need for energy, and that the formation of an acidic mixture inside the steam turbine and/or other components of the thermal power plant is prevented in advance.

In order to achieve a particularly good combustion inside the combustion chamber, it is useful to supply gas containing oxygen, especially pure oxygen and/or air, to the combustion device to create a suitable atmosphere for combustion.

This method of carrying out the invention requires taking into account that the combustion of one fuel is possible only in one favorable atmosphere for combustion. A particularly efficient combustion can be achieved by using pure oxygen, because compared to air, oxygen does not contain other non-combustible ingredients, which can create an atmosphere suitable for combustion only on the condition that they are separated from the air before combustion, for example in an air decomposition device.

In another convenient way of carrying out the invention, the produced aggressive combustion products are separated from the water vapor stream by means of a condenser, which is installed behind

steam turbines.

In practically all combustion processes, combustion products are produced, which are usually drained away, because they can be separated and deposited in the combustion chamber or on other components, and thus limit their function, especially in the case of a long working time.

If, for example, one hydrocarbon is burned as fuel in the thermal power plant according to the invention in an atmosphere consisting of pure oxygen, then at least water and carbon dioxide are produced as combustion products. These combustion products are carried along with water vapor and introduced into the condenser. In known thermal power plants, there is already one built-in condenser, so that, in connection with the design according to the invention, it is not necessary to provide a separate condenser for the removal of combustion products.

When cooling water vapor, which contains combustion products in the form of a mixture of water and carbon dioxide, part of the water from the water vapor is abundantly condensed and almost pure, gaseous carbon dioxide remains as an excess, which is removed from the condenser and can, for example, be stored in a suitable way.

As already mentioned, when using hydrogen as a fuel, which is produced by reforming or gasification of a hydrocarbon, the formed aggressive carbon dioxide can already be removed before introducing the fuel into the combustion chamber, so that in this case practically no carbon dioxide is produced as a combustion product.

By means of the combustion chamber of the thermal power plant according to the invention, the internal additional combustion realized can be very easily made available during the operation of the steam turbine. It only requires the ignition of the fuel that is introduced into the combustion chamber; this eliminates the time required for heating the heating surfaces of known heat exchangers.

Furthermore, the thermal power plant according to the invention achieves the advantage that the combustion products and/or flue gases do not have to be removed from the combustion chamber by means of a special device for their removal, because they are carried along with the flow of water vapor and can be turned off at another point in the circular cycle of water vapor, for example, in the aforementioned condenser. In addition, with the help of the invention, a higher water vapor temperature is achieved, without the need to insert another steam generator.

The thermal power plant according to the invention can be turned on especially for the supply of energy at peak loads or for supporting the network frequency of a power supply network; the thermal power plant according to the invention offers the possibility of quick power regulation and is used very flexibly.

Short description of the image

In the following part, an example of the embodiment according to the invention will be shown in more detail with a picture. She shows:

Figure 1 shows a schematic view of the thermal power plant according to the invention.

Detailed description of the invention

At SLI, a thermal power plant 1 according to the invention is presented, which consists of a steam turbine 3 connected to a current generator 21, as well as a steam generator 5 heated by combustion.

Steam turbine 3 is designed as a three-stage turbine, which has a first stage 11 turbine, a second stage 13 turbine and a third stage 15 turbine, which are designed as a high-pressure stage, a medium-pressure stage, or low pressure level.

In the case of steam generator 5, the method of execution of which is shown in the picture, a boiler heated by coal 27 is used, to which combustion air 29 is supplied for coal combustion.

In the steam generator 5, a heating surface 37 is placed in the area of its hot end, as well as in the area of lower temperatures, the heating surface of the intermediate superheater 35.

The heating surface 37 serves to heat the feed water 24 from the feed water tank 23 in the steam generator 5 so that the steam can be fed to the first stage 11 of the steam turbine.

After partial phasing in the first stage 11 of the steam turbine, the steam is heated using the heating surfaces of the intermediate heater 35. The stream of steam 17 exits the intermediate heater 35 in the direction 9 and is introduced into a heating device (7). At the same time, the water vapor 17 is additionally heated in a combustion chamber 19 by means of a fuel 33 and with the addition of oxygen 31, whereby the water vapor 17 in the combustion chamber 19 is mixed with hot carbon dioxide gases, which are produced in the combustion chamber 19 during the combustion of fuel 33.

The transfer of heat from the hot flue gases to the stream of water vapor 17 is achieved by direct mixing, without the mediation of any heat transfer material, for example, the heating surfaces of the heat exchanger.

Instead of oxygen 31, it is possible to use air to create an atmosphere suitable for combustion, whereby the air, in this case before entering the combustion chamber, is decomposed using a device for decomposition of air into oxygen and remaining gas.

As fuel 33, for example, some hydrocarbon can be used, especially methane or hydrogen.

The water vapor 17 heated by the combustion chamber 19 is supplied to the second stage 13 of the steam turbine, where the turbine then converts at least one part of the energy contained in it into mechanical work. The water vapor relieved in this way leaves the second stage 13 of the steam turbine and is brought to the third stage 15 of the steam turbine, where the remaining energy in the steam can be easily converted into mechanical work.

The expanded and relieved steam leaves the third stage 15 of the steam turbine in the form of a water-steam mixture and is led to the condenser 25, where the remaining steam part of the mixture will condense into water.

This water, which collects in the condenser 25, is supplied as condensate 26 to the feed water tank 23.

Combustion products 39 can be removed from the condenser 25, which are produced during combustion in the combustion chamber 19.

As the combustion process in the combustion chamber 19 takes place within the stream of water vapor 17, the combustion products 39 are carried along with the water vapor 17 in a circular cycle of water vapor and according to this method of carrying out the invention, they are taken out of the condenser 25.

If, for example, a hydrocarbon is burned with oxygen 31 as fuel 33, then the combustion products 3-9 contain water and carbon dioxide. This mixture of water and carbon dioxide is carried along with the stream of water vapor and can be withdrawn from the condenser 25, because when cooling the mixture of water and carbon dioxide, the water part condenses almost completely, so that afterwards completely pure carbon dioxide remains as a gas, which is then removed and, for example, can be stored.

Claims (4)

1. Thermal power plant 1, which consists of at least one panre turbine 3 and one heated steam generator 5, indicated by the fact that one combustion device (7) is placed in the direction (9) of the water vapor flow (17) after the first stage (11) of the turbine, and before the second stage (13) of the steam turbine (3). 2. Thermoelectric power plant 1, according to Claim 1, characterized by the fact that the combustion device (7) is connected to the water for the supply of fuel for hydrogen and/or hydrocarbons, in particular, gas. 3. Thermal power plant 1, according to one of Claims 1 or 2, characterized by the fact that the combustion device (7) is connected to the water for the supply of the oxidizing agent for the supply of gas containing oxygen, especially pure oxygen (31) and/or air, in order to create a favorable atmosphere in the combustion chamber (19). 4. Thermal power plant 1, according to one of Claims 1 to 3, characterized by the fact that waste aggressive combustion products (39) are removed from water vapor (17) by means of a condenser (25) connected after the steam turbine (3).