KR100197741B1 - Method and plant for the generation of steam having a supercritical steam parameter in a continuous-flow steam generator - Google Patents

Abstract

A combustion chamber with an airtight closed-wall pipe, a fossil fuel burner, at least one convection chamber having a convection heating surface downstream of the flue gas side combustion chamber, and at least one intermediate superheating surface, The working medium flows through the enclosed tube wall and has a supercritical steam parameter in a continuous flow steam generator with at least one gas flue that is led through the steam separator at the transition from the evaporator section to the superheater section of the closed tube wall. In the steam generating method, the working medium is derived from the inlet pipe wall 3 of the gas flue 2 at the separation point 15 and at least one part of its thermal energy comes out of the steam turbine 19 by indirect heat exchange. The intermediate superheater of the heat transfer from the heating surface (8) to the heating stone operating medium, and after heat exchange is led back to the inlet pipe wall (3) at the separation point (15), Port 10 temperature was added the required temperature to the temperature of the operating medium in the appropriate places in the plant for carrying out the method the steam generation which is kept below the temperature of the waste material allows the admission wall 3 and a method.

Description

Steam generation method and plant with supercritical steam parameters in continuous stream steam generator

The present invention relates to a combustion chamber having an airtight closed-wall pipe, a combustion chamber having a fossil fuel burner, at least one convection heating surface downstream of a flue gas side combustion chamber, and at least one intermediate superheating surface. Supercritical steam designed in a continuous flow steam generator with at least one gaseous flue, which is designed and flows through the wall of the inlet tube and is introduced through the steam separator at the transition from the evaporator section to the superheater section of the wall. A method and plant for steam generation with parameters.

Continuous steam generators of this type are known from the publication The Steam Generators of the 800-MW Units in the Schwarze Pumpe Power Station-BWK volume 46 (1994) No. 1/2.

In order to reduce CO ₂ emissions and, on the other hand, to achieve a low unit investment cost due to high unit output, an increasing demand for operating a common type of continuous stream steam generator with improved process efficiency, inter alia, is a steam parameter. Is going to increase. In this case, the steam temperature and steam pressure upstream of the turbine in the steam process are increased.

However, there are disadvantages in the practice of increasing the process efficiency, and in addition to the temperature at which the required temperature is added to the elevated steam temperature at a suitable place at the time of outflow of the working medium from the wall of the continuous flow steam generator, the waste inlet pipe can be used. It becomes above the allowable material temperature of the pipe material of the wall.

The development of new materials with higher allowable material temperatures for the enclosed pipe walls has already been considered. However, this presupposes a time-consuming development phase due to the subsequent testing and accreditation procedures for the application of new tubular materials to the continuous-flow steam generator, and therefore is not yet available for immediate or near term needs.

It is an object of the present invention to provide a steam generating method and a plant having a supercritical steam parameter in a continuous flow steam generator, thereby avoiding the disadvantages mentioned above and improving process parameters by improving steam parameters.

1 is a schematic longitudinal cross-sectional view of a continuous flow steam generator according to the prior art.

2 is a schematic longitudinal cross-sectional view of a continuous flow steam generator according to the present invention.

3 is a schematic longitudinal sectional view as in FIG. 2 with another heat exchanger.

4 is a schematic longitudinal sectional view as in FIG. 2 designed as another example.

* Explanation of symbols for main parts of the drawings

1: Continuous flow steam generator 2: Gas flue

3: closed pipe wall 4: combustion chamber or heat dissipation chamber

5,6: Convection room 7: Convection heating surface

8: middle superheater surface 9: inlet of closed wall

10: outlet of closed wall

11: transition opening from the evaporator section to the superheater section of the closed wall

12: transition part outlet conduit 13: transition part inlet conduit

14: steam separator 15: separation point of the inlet pipe wall

16: Separation point outlet port conduit of closed wall

17: Separation point introduction conduit of closed wall

18: 2-flow heat exchanger 19: steam turbine

20: 3-flow heat exchanger 21: flue gas outlet orifice

22: base of gas flue 23: ECO heating surface

24: operation medium collecting means 25: operation medium distribution means

This object is achieved by the features of claims 1 and 9.

The dependent claims relate to more advantageous embodiments of the invention.

The solution according to the present invention provides the following advantages.

1. By increasing the steam parameters, the process efficiency of the steam generator is further increased.

2. Maintain the allowable material temperature of the incoming wall material which can be used now and the plant specific final temperature of the combustion chamber.

Next, embodiments of the present invention will be described in detail with reference to the drawings.

1 to 4, the continuous flow steam generator 1 has one vertical gas flue 2 as an example. However, they can also be designed as two vertical gas flues connected to each other by horizontal gas flues.

The vertical gas flue 2 has a funnel-shaped base 22 like a conventional steam generator using coal at the bottom. However, the base 22 can also be of vertical design, such as a conventional steam generator using gas or oil. 1 to 4, the flue gas discharge orifice 21 is located above the continuous stream steam generator 1 having the vertical gas flue 2. The vertical gas flue 2, essentially having a quadrilateral cross section, is convection downstream of the hermetic closed wall 3, the combustion chamber or heat dissipation chamber 4 with a fossil fuel burner, and downstream of the flue gas side combustion chamber 4; It is designed as a convection chamber 5 having a heating surface 7 and at least one intermediate superheating heating surface 8. In the continuous flow steam generator 1 having two vertical gas flues, the heating surfaces 7 and 8 described above can be partially or completely positioned in the second vertical gas flue and the connecting horizontal gas flue.

The working medium is heated by the heat released during combustion of the fossil fuel in the combustion chamber 4 and flows from the inlet 9 to the outlet 10 through the pipe of the closed inlet pipe wall 3. In this case, according to FIG. 1 showing a known state of the art, the working medium first flows through the evaporator portion of the closed tube wall 3 and then transitions from the evaporator portion of the closed tube wall 3 to the superheater portion. In the section 11, the superheated steam which is led through the steam separator 14 and separated in the steam separator is led to the superheater portion of the inlet pipe wall 3. The evaporator portion of the closed pipe wall 3 has a pipe of inclined surface, but may also have a pipe of vertical surface in the same manner as the superheater portion. In addition, the superheater portion of the closed tube wall 3 may also have a coiled tubing downstream of the separating point 11. The working medium passes from outlet 10 through conduit (not shown) to one or more convective heating surfaces 7 and then through steam turbine 19. The low pressure expanded working medium becomes hot at one or more intermediate superheated surfaces 8 and is supplied to a steam turbine (not shown). The ECO heating surface 23 is located upstream of the evaporator portion of the closed tube wall 3 with respect to the flow direction of the working medium.

Depending on the tube diameter and the calculated pressure, a high temperature material such as, for example, 13 CrMo 44 having an allowable material temperature of up to about 530 ° C. is used as the material for forming the tube of the closed wall 3.

The temperature necessary for the temperature of the superheated steam at a suitable place at the outlet 10 of the closed inlet pipe wall 3 when the steam parameter of the continuous flow steam generator 1 according to FIG. 1 is increased to achieve high efficiency of the process. The temperature at which is added exceeds the maximum allowable material temperature of the inlet pipe wall 3, while at the same time the allowable temperature of the plant specific flue gas is maintained at the end of the combustion chamber.

In order to achieve an increase in the steam parameters, at the same time to maintain the allowable temperature of the plant-specific flue gas at the end of the combustion chamber, and at the same time to adopt the material of the waste pipe wall currently used, as shown in Figs. In the continuous stream steam generator 1 according to the present invention, heat transfer from the closed wall 3 to the intermediate superheated heating surface 8 occurs. This can allow the temperature of the superheated steam below the allowable material temperature to be led through the outlet 10 of the closed wall 3.

Next, as shown in FIGS. 2 to 4, the working medium from the continuous-flow steam generator 1 according to the present invention is subjected to the closed inlet pipe wall 3 of the gas flue 2 at any separation point 15. From the steam turbine 19 (not shown) and transferred to the working medium to be heated on the intermediate superheater surface 8 by indirect heat exchange, and after separation, the separation point 15 Is led back to the closed wall 3.

At a separation point 15 which is located essentially at the horizontal plane in at least a partial region of the wall, preferably essentially horizontal to the entire wall of the enclosed duct wall 3, the working medium flowing from the bottom to the top, for example, may be one or more headers. It is mixed and collected in the working medium collecting means 24 and supplied to at least one heat exchanger, which may be an external two-flow heat exchanger 18 according to FIG. 2, through at least one separation point outlet conduit 16. . After the heat exchange takes place, the working medium is then evenly distributed via at least one separation point inlet conduit 17 and one or more working medium distribution means 25, which may be, for example, a distributor so that it is heated again. Is introduced into the closed wall 3.

However, the operating medium induced at the separation point 15 can also transfer some of its thermal energy in at least one intermediate superheater surface 8 designed as a three-flow heat exchanger 20 according to FIG. 3.

However, the separation point 15 of the closed tube wall 3 is in the region of the combustion chamber 4 of the transition portion 11 from the evaporator portion of the closed tube wall 3 to the superheater portion with respect to the flow direction of the working medium. It is preferable to design downstream, but the separation point 15 may also be designed upstream of the transition portion 11, and may also be the same place as the transition portion 11, as shown in FIG. In this case, the working medium is led to the steam separator 14 through at least one outlet conduit 12, wherein the separated superheated steam is at least one external two-flow heat exchanger 18 and at least one inlet diagram. It is led back through the pipe 13 to the closed pipe wall 3, where a part of the thermal energy of the superheated steam is released from the steam turbine 19 (not shown) by indirect heat exchange and the intermediate superheated heating surface 8 Is transmitted to the operating medium to be heated. The heat exchange can also take place in at least one intermediate superheater heating face 8 designed as a three-flow heat exchanger 20, instead of the external two-flow heat exchanger 18.

The heat absorption of the working medium in the inlet pipe wall 3 including the heat transfer according to the invention from the separation point 15 to the intermediate superheated heating surface 8 is carried out at the outlet 10 of the inlet pipe wall 3. It is preferably designed in such a way that the temperature at which the required temperature is added to the temperature of the operating medium at the appropriate place is kept below the allowable material temperature of the closed tube wall 3, preferably 0 to 50K. In this case, the temperature at which the temperature required for the temperature of the working medium is added at an appropriate place at the outlet 16 of the separation point 15 may be a preferable temperature range below the allowable material temperature of the inlet pipe wall 3.

However, as described above, the heat absorption of the working medium in the closed wall 3 including heat transfer according to the present invention is also performed by the outlet 16 and the closed wall 3 of the separation point 15. It can be designed in such a way that the temperature at which the required temperature is applied to the temperature of the operating medium at a suitable place at the outlet 10 is kept below the allowable material temperature of the inlet pipe wall 3, preferably 0 to 50K. In the case of tubing materials currently available, for example 13 CrMO 44, the temperature of the working medium at the outlets 16 and 10 should preferably be about 445-495 ° C. However, if the outlet 16 is not located primarily in the convective heat transfer zone, and the heat exchange is located in the zone where the heat is mainly caused by heat dissipation, the temperature of the operating medium should preferably be about 430-480 ° C. when the above-described materials are used. do.

The addition of temperature, which can be considered at appropriate locations for the calculation of steam generator pipe walls, is generally governed by national regulations such as TRD, ANSI or ASME. For example, according to the TRD for the design of the heating surface through which steam passes, the temperature addition of 35K is essentially required in the convection region, and the addition of 50K is essentially required in the heat dissipation region.

Claims (17)

A combustion chamber with an airtight closed-wall pipe, a fossil fuel burner, at least one convection chamber having a convection heating surface downstream of the flue gas side combustion chamber, and at least one intermediate superheating surface, The working medium flows through the enclosed tube wall and has a supercritical steam parameter in a continuous flow steam generator with at least one gas flue that is led through the steam separator at the transition from the evaporator section to the superheater section of the closed tube wall. In the steam generating method, the working medium is derived from the inlet pipe wall 3 of the gas flue 2 at the separation point 15 and at least one part of its thermal energy comes out of the steam turbine 19 by indirect heat exchange. Is transferred to the working medium to be heated on the heating surface (8), and after heat exchange, is led back to the inlet pipe wall (3) at the separation point (15), and the vessel of the inlet pipe wall (3) Port 10 temperature was added the required temperature to the temperature of the operating medium in the appropriate place in the vapor generating method characterized in that the material temperature remains below allow for the admission of the closed wall (3). 2. The steam according to claim 1, wherein the temperature at which the separation point 15 is applied to the temperature of the operating medium at a suitable place at the outlet 16 is maintained below the allowable material temperature of the inlet pipe wall 3. How it occurs. The temperature according to claim 1 or 2, wherein the temperature to which the temperature of the working medium is applied at a suitable place at the outlets 10 and 16 is maintained at 0 to 50 K which is less than or equal to the allowable material temperature of the inlet pipe wall 3. Steam generation method. Separation point (15) according to any one of the preceding claims, characterized in that the separation point (15) is located downstream of the transition (11) from the evaporator section of the closing wall (3) to the superheater section with respect to the flow direction of the working medium. Steam generation method. Separation point (15) according to any one of the preceding claims, characterized in that the separation point (15) is located upstream of the transition portion (11) from the evaporator portion of the closing wall (3) to the superheater portion with respect to the flow direction of the working medium. Steam generation method. The working medium is a closed pipe of gas flue (2) according to any one of claims 1 to 3, wherein the operating medium is at the separation point (15) which is the same place as the transition portion (11) from the evaporator portion to the superheater portion of the closed tube wall (3). After operating from the wall (3) and through the steam separator (14), a part of its thermal energy is discharged from the steam turbine (19) by indirect heat exchange to be heated in the intermediate superheater (8). Steam generation, characterized in that it is guided back to the inlet pipe wall (3) at the separation point (15) after heat exchange. The steam generating method according to claim 1, wherein the heat exchange takes place in at least one external two-flow heat exchanger. The steam generating method according to claim 1, wherein the heat exchange takes place in at least one intermediate superheater surface (8) designed as a three-flow heat exchanger (20). Combustion chamber with airtight closed tube wall, fossil fuel burner, at least one convection chamber having a convection heating surface downstream of the flue gas side combustion chamber, and at least one intermediate superheater heating surface, the operating medium being closed The vapor of any one of claims 1 to 8 in a continuous flow steam generator having at least one gas flue that flows through the inlet wall and is led through a vapor separator at the transition from the evaporator section to the superheater section of the closed wall. In a plant for carrying out the generating method, at the point of separation 15 of the enclosed conduit wall 3 of the gas flue 2, the working medium comprises at least one means for indirect heat exchange through at least one outlet conduit 16. And then transfer a portion of its thermal energy from the steam turbine (19) to the operating medium to be heated on at least one intermediate superheater (8) and at least A single inlet conduit (17) is introduced from the separation point (15) to the closing wall (3) and the temperature required for the temperature of the operating medium at an appropriate location at the outlet (10) of the closing wall (3). A plant for executing a steam generating method, characterized in that the applied temperature is kept below the allowable material temperature of the closed pipe wall (3). 10. The plant according to claim 9, wherein the temperature at which the separation point 15 is applied to the temperature of the operating medium at a suitable place at the outlet 16 is maintained below the allowable material temperature of the inlet pipe wall 3. . 10. The plant according to claim 9, characterized in that the separation point (15) is located downstream of the transition (11) from the evaporator section of the closing tube wall (3) to the superheater section with respect to the flow direction of the working medium. 10. The plant according to claim 9, characterized in that the separation point (15) is located upstream of the transition (11) from the evaporator section of the closing tube wall (3) to the superheater section with respect to the flow direction of the working medium. 10. The separation point (15) according to claim 9, wherein the separation point (15) is the same as the transition (11) from the evaporator portion to the superheater portion of the closed inlet pipe wall (3) and the working medium is vaporized through at least one outlet plate (12). The steam supplied to the separator 14 and also derived from the steam separator is supplied to at least one indirect heat exchange means, where part of its thermal energy comes from the steam turbine 19 and at least one intermediate superheater is heated. And (8) a transfer to the working medium to be heated, which is led to the closing wall (3) at the separation point (15) via at least one inlet conduit (13). The plant according to claim 9, wherein at least one external two-flow heat exchanger is used as the heat exchange means. 14. Plant according to one of the claims 9 to 13, characterized in that at least one three-flow heat exchanger (20) is designed as an intermediate superheating surface (8) and used as a heat exchange means. The plant as claimed in claim 9, characterized in that the separating point (15), essentially located in the horizontal plane, is excreted in at least part of the area of the one closed wall. 17. The apparatus according to any one of claims 9 to 16, wherein at least one working medium collecting means (24) is located upstream of the outlet conduits (12, 16) with respect to the flow direction of the working medium, 25) which is located downstream of the inlet conduits (13, 17).