CZ2014666A3 - Device to generate electric power by making use of steam-gas mixture - Google Patents

Abstract

In the circuit of the combustion chamber (1), gas turbine (7) mixer (10) and steam-gas heater (6), a steam turbine (14) is connected to the steam line (11) with a second electric generator (15). by entering the combustion chamber (1) and the outlet towards the mixer (10). Preferably, at least one steam superheater (17) located inside the combustion chamber (1) is connected upstream of the steam turbine (14). Optionally, a sampling line (16) is led between the combustion chamber (1) and the mixer (10) from the steam line (11).

Description

Technical field

The invention relates to the field of power engineering. A device for generating electricity from solid fuels using a steam-gas mixture is proposed, comprising a gas turbine circuit and a upstream steam turbine.

BACKGROUND OF THE INVENTION

Various devices for producing electricity from solid fuels are known. In the case where the device comprises a gas turbine, the working medium of the gas turbine is usually a steam-gas mixture. These devices use a combined steam-gas cycle, and therefore a suitable circuit, such as a Rankin steam cycle circuit, is connected downstream of the gas turbine.

A specific type of such a device is described in CZ PV 2007-340 and CZ U 26344. The basic element of these devices is a combustion chamber for the combustion of solid fuels of the cooled type, i.e. with water-cooled walls. The apparatus according to both documents also includes a gas turbine equipped with an electric generator and coupled to a compressor, a mixer, a steam-gas heater and the necessary interconnecting piping. The combustion chamber, which is suitable, for example, for the combustion of coal, has a water supply for water cooling. The combustion chamber is led out of the flue gas duct, which is further led out of the device through a steam-gas heater, and on the other hand a steam duct for evacuating the cooled steam. The steam line is led from the combustion chamber to the mixer. The air duct from the compressor is also connected to the mixer. In the mixer, the supplied steam is mixed with air from the compressor to form a steam-gas mixture, which is the working medium for the gas turbine. Thus, a steam-gas pipeline is connected from the mixer to which a gas turbine is connected. A steam-gas heater is connected to the steam-gas piping between the mixer and the gas turbine. A Rankin steam cycle circuit is connected downstream of the gas turbine. This includes a waste heat steam generator with steam-gas piping, led to the steam-gas exhaust for discharging the steam-gas mixture from the steam-gas mixture. And further comprising at least one steam turbine, a condenser and a storage tank for replenishing feed water. After the steam-gas heater, an air heater is connected on the flue gas duct for heating the combustion air. In this case, an air preheater for preheating the combustion air is connected downstream of the waste heat steam generator, and an air conduit is introduced into the steam-gas conduit, which is then routed through the air heater to the air inlet of the combustion chamber. Condensate piping for condensate discharge from the steam-gas mixture is also led out of the air preheater. Before entering the steam-gas heater, in the case of a multi-part steam-gas heater before entering the at least one part thereof, an injection cooler with a connected water pipe is connected to the steam-gas pipe.

A disadvantage of existing plants of the above-mentioned type is that by cooling the combustion chamber, saturated steam is produced whose pressure is equal to that of the air supplied by the compressor and therefore cannot be utilized energetically. A further disadvantage is that it is difficult to find a possible use for low pressure saturated steam, so that all the amount of steam produced in this way has to be used for the production of the steam-gas mixture and thus the water vapor content of the steam-gas mixture cannot be controlled.

SUMMARY OF THE INVENTION

The above disadvantages substantially limit the invention. The proposed apparatus for generating a steam-gas mixture comprises at least one refrigerated type combustion chamber, at least one gas turbine provided with a first electric generator and compressor, at least one mixer, and at least one steam-gas heater. From the combustion chamber there is a flue gas duct, which is led out of the device through the steam-gas heater, and a steam duct. This steam pipe has an end connected to the mixer. The mixer also has an air duct that leads to it from the compressor. A gas turbine is led out of the mixer via a steam-gas heater, on which a gas turbine is further connected, considered in the direction of the medium flow. The essence of the new solution is that between the combustion chamber and the mixer, there is a: · · · · · · · · · · · · · · · · · · · · · · · · · At least one steam turbine equipped with a second electric generator is connected to the steam piping. The steam turbine is connected by its inlet to the steam line section leading from the combustion chamber and by its outlet to the steam line section leading to the mixer, all considered in the direction of flow of the medium.

Preferably, at least one steam superheater is connected to the steam line. According to the invention, the steam superheater is located in the combustion chamber and is connected to a section of the steam line upstream of the steam turbine.

For both the superheater circuit and the superheater variant, a sampling line for the removal of excess steam, for example for energy recovery, can advantageously be led from the steam line, namely between the combustion chamber and the mixer.

All of the above directions and connections, such as behind, before, and the like, are to be understood according to the direction of flow of the medium in the operating state of the device.

The solution according to the invention is suitable for use as a power source or as a cogeneration power source with solid-fuel combustion. The device according to the invention may burn fossil fuels, such as coal, or alternative fuels, such as pellets, or possibly waste. The invention can optimally be used for the apparatus according to CZ PV 2007-340 and CZ U 26344. The advantage of the apparatus according to the invention is that it enables to utilize the steam generated by water cooling of the combustion chamber. Another important advantage of this device is that, in the operation of the plant, it is possible to control the water vapor content of the steam-gas mixture, and it is possible to divert excess amounts of steam produced for further use, e.g.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is illustrated by the drawings in which: FIG. 1 shows an exemplary device according to a first exemplary embodiment, FIG. 2 shows an exemplary device as in the previous figure and in addition with a sampling line, FIG. 3 shows an exemplary embodiment with an superheater, according to a second embodiment, and FIG. 4 shows an exemplary embodiment as in the previous figure and additionally with a sampling line.

··· ···· · ··································································

DETAILED DESCRIPTION OF THE INVENTION

Example 1

An illustrative embodiment of the proposed technical solution is a device for generating electricity using a steam-gas mixture according to FIG. 1 and FIG. 2.

The basic element of the device according to FIG. 1 is a combustion chamber 1 of the cooled type, i.e. with water-cooled walls supplied by a water pipe

2. The combustion chamber 1 may be with any fireplace used to burn fossil and alternative fuels. It has a fuel supply line 3 for supplying fuel and an air supply line 4 for supplying combustion air. From the internal space of the combustion chamber 1, a flue gas duct 5 is provided, which serves for the removal of the flue gases resulting from the combustion of the fuel. A flue gas heater 6 is connected to the flue gas duct 5, from which the flue gas is then discharged for further utilization of residual heat, for example for heating combustion air or for producing hot or hot water serving as a medium for heating a hot water system of buildings. It comprises a gas turbine 7 provided with a first electric generator 8 and a compressor 9 and a mixer 10. From the combustion chamber 1 a steam line 11 is led out of the combustion chamber 1, the end of which is connected to a mixer 10. A gas turbine 7 is discharged from the mixer 10 from the mixer 10, this is led through the gas-fired heater 6 and a gas turbine 7 is connected to the gas-fired pipeline 13 in the circuit after the gas-fired heater 6. a steam turbine 14 provided with a second electric The connection of the steam turbine 14 in the circuit is as follows. The steam turbine 14 is connected with its inlet to a section of steam line 11 leading from the combustion chamber 1 and its outlet is connected to a section of steam line 11 continuing from there to the mixer 10.

In operation of the plant, the cooling water supplied by the water line 2 evaporates in the walls of the combustion chamber 1 by the effect of the heat from the combusted fuel, and the resulting steam with the steam line 11 passes through the steam turbine 14 to the mixer 10. In the mixer 10, the steam is mixed with the air supplied by the compressor 9 through the air duct 12 to form a steam-gas mixture. The produced steam-gas mixture is discharged from the mixer 10 through the steam-gas line 13 through the steam-gas

9 9 9 9 9

9 9 9 9 9 9 9 9 99

9 9 9 99 99 heater 6, where it is heated to the working temperature of the gas turbine 7, whereupon in such a heated state the steam-gas mixture from the steam-gas heater 6 is fed to the gas turbine 7. After expansion in the gas turbine 7, the steam-gas mixture is diverted for further use, for example, to generate electricity in a connected Rankin steam cycle circuit (not shown in Fig. 1) and / or to a hot-water heat supply system.

In this apparatus, the combustion gases produced by the combustion of fossil fuel-type fuel, such as coal and / or alternative fuel, are cooled in the cooled combustion chamber 1 to the exhaust gas outlet temperature in the flue gas duct 5 always lower than the ash melting temperature. For example, the flue gas can be cooled to 1,100 ° C. Cooling water is supplied via water line 2 to the combustion chamber 1 at a pressure higher than the pressure of the air exiting the compressor 9. The supply water may have a pressure of 4 MPa, for example 1.2 MPa. The heat of cooling of the flue gas evaporates this cooling water and the resulting saturated steam, for example at a pressure of 4 MPa, expands in a steam turbine 14, in this embodiment preferably in a backpressure steam turbine 14, to air pressure as in mixer 10, e.g. , 2 MPa. The pressure of the steam produced in the wall-cooling system of the cooled combustion chamber 1, thus the pressure of the steam at the inlet to the back-pressure steam turbine 14, is always adjusted depending on the air pressure supplied by the compressor 9. Also, the steam turbine 14 operates at a so-called sliding pressure. By cooling the combustion chamber 1, not only steam is produced to produce the steam-gas mixture in the mixer 10, but also electricity is produced as a result of its higher pressure. This additional electricity is produced during the steam expansion in the steam turbine 14 in the connected second electric generator 15. This embodiment variant has the disadvantage that the saturated steam pressure upstream of the steam turbine 14 and hence the amount of electricity produced in the second electric generator 15 is limited. permissible humidity of steam exiting the steam turbine 14.

In addition, the apparatus may be provided with a sampling line 16 for removing excess steam, as shown in Figure 2.

The sampling line 16 is discharged from the steam line 11 from its section between the combustion chamber 1 and the mixer 10. In the example shown, the sampling line 16 is connected between the back pressure steam turbine 14 and the mixer. ··· · · · · · · · · · · · · ·

10. Alternatively, it may be connected between the combustion chamber 1 and the steam turbine 14. If more steam is produced by cooling the combustion chamber 1 than is necessary to produce the steam-gas mixture in the mixer 10, then excess steam is discharged via sampling line 16 outside the mixer 10 and subsequently. is used, for example, for the supply of heat, or as process steam, etc. In this case, a sufficient amount of cooling water is supplied through the water line 2 to ensure a safe cooling of the combustion chamber 1. If the amount of steam so produced is greater than the amount of steam required to produce the steam-gas mixture in the mixer 10, then the excess amount of steam is taken off the mixer 10.

Example 2

3 and FIG. 4.

FIG. 3 differs from the embodiment shown in FIG. 1 in that a steam superheater 17 is additionally included. This is connected to the steam line 11 and is located inside the combustion chamber 7. The steam superheater 17 is connected to a section of the steam line 11 located upstream of the steam turbine 14, considered in the direction of flow of the medium. In the so placed and connected steam superheater 17, the saturated steam produced by cooling the walls of the combustion chamber 1 is superheated to a higher temperature and the thus slightly superheated steam is then fed to the backpressure steam turbine 14. If as in the previous example, i.e. the stated 1,100 ° C, the amount of heat transferred to produce saturated steam and to overheat the saturated steam to a higher temperature remains the same. The steam superheater 17 must therefore be selected in such an embodiment as to ensure the desired slight overheating of all the saturated steam produced by the cooling of the combustion chamber 1. The advantage of this alternative device is that it allows to increase the steam pressure upstream of the steam turbine 14 a second electric generator 15.

In this embodiment variant, the sampling line 16 can also be led out of the steam line 11, as shown in FIG.

Also in the case of the variant of the device according to FIG. 4, the sampling line is discharged from the steam line 11 between the combustion chamber 1 and the mixer 10.

In the example shown, the sampling line 16 is also connected between the two of them. Again in this case, it can alternatively be connected between the combustion chamber 1 and the steam turbine 14. If more steam is produced by cooling the combustion chamber 1 than is necessary to produce the steam-gas mixture in the steam-gas mixture. mixer 10, then the excess amount of steam is discharged via sampling line 16 outside mixer 10 and subsequently used, for example, for heat supply, or as process steam, etc. Water line 2 supplies enough cooling water to ensure safe combustion chamber 1 cooling. . If the amount of steam so produced is greater than the amount of steam required to produce the steam-gas mixture in the mixer W, then the excess amount of steam is removed outside the mixer 10.

Claims (3)

PATENT CLAIMS An apparatus for generating a steam-gas mixture comprising at least one refrigerated type combustion chamber (1), at least one gas turbine (7) provided with a first electric generator (8) and a compressor (9), at least one mixer (10) and at least one a steam-gas heater (6) wherein the combustion chamber (1) is led out of the flue gas duct (5), which in turn passes through the steam-gas heater (6) out of the device, and steam duct (11), the end of which is connected to the mixer (10), and the air duct (12) is also introduced into the mixer (10), which is supplied from the compressor (9), and the steam-gas duct (13) is discharged from the mixer (10). a steam-gas heater (6) followed by a gas turbine (7) connected to the steam-gas pipe (13), characterized in that a steam-gas pipe is located between the combustion chamber (1) and the mixer (10) (11) connected at least one steam turbine (14) provided with a second electric generator (15), said steam turbine (14) being connected by its inlet to a section of steam line (11) extending from the combustion chamber (1) and outlet to a section of steam line (11) leading to the mixer (10). The steam-gas generating plant according to claim 1, characterized in that at least one steam superheater (17) is connected to the steam line (11), the steam superheater (17) being located in the combustion chamber (1). and is connected to a section of the steam line (11) upstream of the steam turbine (14). The steam-gas mixture generating plant according to claims 1 and 2, characterized in that a sampling line (16) for the removal of excess steam is led from the steam line (11) between the combustion chamber (1) and the mixer (10), for example for energy use.