CN1842638A - Steam power plant - Google Patents

Abstract

An inventive steam power plant (1) comprises at least one steam turbine (2) and a steam generator (5), whereby a combustion chamber (19), in the direction (9) of the flow of steam (17), is mounted after a first turbine stage (11) and before a second turbine stage (13) of the steam turbine (3), and the flow of steam (9) inside a combustion chamber (19) can be heated by mixing it with a hot gas that can be produced inside said combustion chamber (19).

Description

steam power plant

The invention relates to a steam power plant with at least one steam turbine and a fired steam generator.

In known steam power plants, the working steam for the steam turbine is usually produced in a single-fired steam generator, where the heat contained in the hot gas (heiβgas) is sent to one or more heat exchangers If water is added to these heat exchangers, working steam can be generated by heating the water, or steam can be input to these heat exchangers, and the steam can be superheated by means of a heat exchanger mentioned later; Such superheating takes place in known steam turbines, for example between the high-pressure stage and the medium-pressure stage of the steam turbine, wherein the steam leaving the high-pressure stage is heated by means of an intermediate superheater arranged in the steam generator is overheated and sent to the medium pressure stage.

This resuperheating of the steam contributes, for example, to a higher efficiency of the steam turbine.

In known steam power plants, thermal energy is supplied for generating steam and/or for resuperheating steam by means of heat exchanger surfaces which are arranged in the fired steam generator, for example in a Combustion of coal or oil or biomass or collectively referred to as fossil fuel or nuclear fired steam boilers and in contact with hot gases conducted in steam generators. The heated heat exchanger surfaces in turn transfer their heat energy to the water and/or steam circulating in the heat exchanger body formed by the heat exchanger surfaces. That is, the heating is effected by transferring the heat of the hot gas to the heat exchanger surfaces and from there to the medium to be heated.

Because for the heat exchangers known in the prior art that are installed in the steam generators of known steam power plants, the thermal energy of the hot gas is transferred by means of the material of the heat exchanger surface heated by the hot gas To the medium to be heated, and thus the amount of thermal energy that can be transferred to the medium to be heated, for example water and/or steam, is limited by the material properties of the heat exchanger surfaces.

The permissible steam temperature is therefore limited in known steam power plants, since the heat exchanger surfaces transferring heat cannot be heated to arbitrarily high temperatures due to their material properties and the associated thermal load limits.

In addition, the transfer of the heat of the hot gas to the medium to be heated suffers from a delay, which is mainly caused by the required warm-up time of the heat exchanger surfaces.

Therefore, the technical problem to be solved by the present invention is to provide a steam power plant with at least one steam turbine and an ignition combustion steam generator, which can be used flexibly and overcomes the problems of the prior art. mentioned disadvantages.

The aforementioned technical problem is solved by a steam power plant comprising at least one steam turbine and a fired steam generator, according to the invention following a first turbine stage of said steam turbine in the direction of steam flow and A combustion chamber is arranged upstream of a second turbine stage, and the steam flow can be heated in the combustion chamber by mixing with a hot gas that can be generated in the combustion chamber.

Here, the invention is based on the idea that the transfer of thermal energy from a hot gas to the medium to be heated is comparable to that of the prior art, if no heat exchanger is used to transfer thermal energy to the medium to be heated. are less restricted than .

This is achieved in the invention by direct introduction of the steam stream to be heated into a combustion chamber and mixing there directly with the hot gas.

This internal auxiliary combustion according to the invention can be used for superheating live steam in the steam flow direction after the steam generator and before the steam turbine or for superheating steam which has already transferred part of its energy to a turbine stage and after passing according to The superheated steam of the present invention is transferred to another turbine stage.

Compared with the prior art, with the steam power plant according to the invention higher steam temperatures can be achieved, which contribute to a higher efficiency of the steam power plant.

In the steam power plant according to the invention, if the auxiliary burner realized by means of the combustion chamber is switched off or fails, the steam power plant can still be operated as a known steam power plant.

Hydrogen and/or a hydrocarbon, in particular methane, can advantageously be supplied as fuel to the combustion chamber.

Said fuel especially comprises carbon and/or hydrogen.

The first advantage of using hydrogen as a fuel is that, if hydrogen is produced from a hydrocarbon by fuel reforming or vaporization, as is often the case, the by-product carbon dioxide can be used in the reformation of the hydrocarbon mixture as early as during hydrogen production. The recuperation or vaporization is suppressed with relatively low energy expenditure, so that the formation of acidic steam mixtures within the steam turbine and/or other components of the steam power plant is avoided from the outset.

In order to achieve particularly good combustion in the combustion chamber, an oxygen-containing gas, in particular pure oxygen and/or air, can advantageously be supplied to the ignition combustion device in order to form a combustion atmosphere.

This embodiment of the invention takes into account the requirement that the combustion of a fuel can only be achieved in a suitable combustion atmosphere. A particularly efficient combustion can be achieved with the help of an input of pure oxygen, since pure oxygen contains no other combustion-hindering constituents than air, which sometimes have to be separated before combustion, for example in an air separation plant, in order to create a A suitable combustion atmosphere.

In a further preferred embodiment of the invention, the combustion products produced can be separated off from the steam stream by means of a condenser connected downstream of the steam turbine.

In practically all combustion processes, combustion products are produced which must mostly be discharged, since these can deposit in the combustion chamber or other components and limit their function, especially after a relatively long operating time.

If hydrocarbons are combusted as fuel in a steam power plant according to the invention, for example, in an atmosphere of pure oxygen, the combustion products include at least water and carbon dioxide. These combustion products are carried along with the vapor flow and directed towards the condenser. In known steam power plants most of them are provided with a condenser, so in the present invention it is not absolutely necessary to provide a separate condenser which is suitable for obtaining the combustion products.

When cooling the steam containing the combustion products in the form of a mixture of water and carbon dioxide, the water component is essentially condensed and almost pure carbon dioxide remains in gaseous form, which can be taken from the condenser and stored, for example.

As already mentioned, when hydrogen produced by means of reforming or vaporizing hydrocarbons is used as fuel, the by-product carbon dioxide is already extracted before the fuel is fed into the combustion chamber, so in this case In fact, no carbon dioxide is produced as a product of combustion during combustion.

The internal auxiliary burner realized by means of the combustion chamber of the steam power plant according to the invention can be quickly put into use during the operation of the steam turbine. For this, it is only necessary to ignite the fuel fed into the combustion chamber; this in particular eliminates the known preheating times of the heat exchanger surfaces.

In addition, a steam power plant according to the invention has the advantage that it is not necessary to discharge the combustion products and/or exhaust gases from the combustion chamber by means of a separate discharge device, because the combustion products can be carried by the steam flow and It is separated off elsewhere in the steam cycle, for example at the mentioned condenser. Furthermore, a higher steam temperature can be achieved by means of the invention without having to change the design of the steam generator.

Especially can adopt a steam power plant according to the present invention to provide electric energy or be used to support the grid frequency of a power supply network in the peak hour of power consumption; Apply flexibly.

An embodiment of the present invention is described in detail below.

Figure 1 shows a steam power plant according to the invention.

The drawing shows a steam power plant according to the invention comprising a steam turbine 3 connected to a generator 21 and a combustion steam generator 5 .

The steam turbine 3 is of three-stage construction and has a first turbine stage 11 , a second turbine stage 13 and a third turbine stage 15 , which are respectively designed as high-pressure, medium-pressure and low-pressure stages.

In the embodiment shown in the figures, the steam generator 5 is a coal-fired boiler 27 to which combustion air 29 is fed to keep the coal burning.

A heating surface 37 is arranged in the region of the hot end of the steam generator 5 and a reheater heating surface 35 is arranged in a lower temperature region.

The heating surface 37 serves to heat the supply water 24 from a water supply container 23 in the steam generator 5 in such a way that operating steam can be directed to the first turbine stage 11 .

After partial expansion work in the first turbine stage 11 , the steam is resuperheated by means of the reheater heating surface 35 . The steam flow 17 exits the reheater heating surface 35 in direction 9 and is directed to an ignition burner. Here, the steam flow 17 is heated in a combustion chamber 19 by means of a fuel 33 and the addition of oxygen 31. At this time, the steam flow 17 is generated in the combustion chamber 19 and the combustion of the fuel 33 in the combustion chamber 19. hot gas mixture.

Thus, the heat transfer from the hot gas to the steam flow 17 takes place directly by mixing, without the use of a material, for example a heat exchanger surface, for the heat conduction.

Instead of oxygen 31 , air can also be used to form a suitable combustion atmosphere, wherein the air is optionally separated into oxygen and residual gases by means of an air separation device before being introduced into the combustion chamber.

For example, hydrocarbons, in particular methane or hydrogen, can be used as fuel 33 .

The steam flow 17 heated by means of the combustion chamber 19 is directed to the second turbine stage 13 , where the steam flow 17 converts at least part of the energy contained in it into mechanical work. The work-expanded steam then leaves the second turbine stage 13 and is guided to the third turbine stage 15 , where the energy still remaining in the steam is converted into mechanical energy as well as possible.

The expanded steam leaves the third turbine stage 15 in the form of a water-steam mixture and is directed to a condenser 25 in which the still present steam components are condensed to form water.

This water collected in the condenser 25 is delivered to the water supply container 23 as condensate 26 .

Combustion products 39 produced during combustion in the combustion chamber 19 can be withdrawn from the condenser 25 .

Since the combustion in the combustion chamber 19 takes place inside the steam flow 17, the combustion products 39 are carried by the steam flow 17 into the steam cycle and subsequently withdrawn from the condenser 25 according to an embodiment of the invention.

If, for example, a hydrocarbon is combusted as fuel 33 together with oxygen 31 , the combustion products 39 include water and carbon dioxide. This water-carbon dioxide mixture is carried along with said steam stream 17 and can be extracted from the condenser 25, because when the water-carbon dioxide mixture is cooled, the water content therein is largely condensed and almost pure The carbon dioxide in gaseous form remains as a gas, which can then be discharged and, for example, stored.

Claims (4)

1. a steam power station (1), it comprises the steam generator (5) of at least one steam turbine (3) and an ignition, it is characterized by: one first turbine stage (11) that a firing chamber (7) are placed in described steam turbine (3) along the direction (9) of vapor stream (17) afterwards and at one second turbine stage (13) before, and described vapor stream (17) can be by being heated with a kind of hot combustion gas mixing that can produce in this firing chamber (19) in this firing chamber (19).

2. according to the described steam power station of claim 1 (1), it is characterized by: can carry hydrogen and/or a kind of hydrocarbon, especially methane act as a fuel (33) to described ignition device (7).

3. according to claim 1 or 2 described steam power stations (1), it is characterized by:, can carry a kind of oxygen containing gas, especially purity oxygen (31) and/or air to described ignition device (7) in order in described firing chamber (19), to form a kind of combustion atmosphere.

4. according to each described steam power station (1) in the claim 1 to 3, it is characterized by: be connected described steam turbine (3) condenser (25) afterwards by means of one and from described vapor stream (9), obtain the products of combustion (39) that is produced.

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