DE19507335C2 - Steam generator - Google Patents

Description

The invention relates to a lignite-fired once-through steam generator in one train construction, in which the combustion chamber tube walls flowed through with working fluid and the Flue gas duct surround pipe walls for the secondary heating surfaces above the burner Chamber are formed in a welded tube-web-tube version, the steam generator openings for the connection of return suction shafts for the removal of a Have a subset of flue gas with an interior through which working fluid flows wall pipes are provided.

Such a steam generator (Boxberg IV) is published by the magazine BWK, Vol. 45 (1993), No. 7/8 - July / August, pages 325-331. This well-known steam generator was designed for high steam parameters, i.e. H. the temperatures and pressures on the HP / Zü side are 545 ° C / 563 ° C or approx. 261 bar and approx. 54 bar. The Rauchgastem temperature at the end of the combustion chamber is approx. 950 ° C. The openings for the connection return shafts are usually located in the upper area of the combustion chamber but also within the flue gas flue surrounding pipe walls for the secondary heating be arranged surface.

It is disadvantageous when specifying such high steam parameters and a low combustion comb end temperatures that cause the medium temperature in the steam generator gerrohrwand very high and the limit of use of the conventional material, such as e.g. B. 13 CrMo 44.

The object of the invention is to provide a steam generator of the type described above create at which the medium temperature in the pipe wall below the application limit of the pipe wall material.

This object is ge according to the characterizing features of claim 1 solves.

Further advantageous embodiments of the invention can be found in the subclaims men.  

Through the measures according to the invention and depending on the size of the flue gas Rear suction shafts arranged heating surfaces (inner wall tubing) can be an Absen the temperature of the working medium at the outlet of the flue gas duct surrounding pipe walls for the secondary heating surfaces through this switching option in which the sucked Flue gas is cooled by 60 K to be achieved by approx. 7 K. In principle, depending on Size of the heating surface in the flue gas return shafts also larger reductions of the working fluid temperature at the outlet of the flue pipe surrounding pipe walls will.

Through the measures according to the invention, the steam parameters of such steam The generator can be increased even further or there is the possibility of changing the medium temperature and below the operating limit of the pipe material used to contribute to further increasing the safety and service life of the system.

The invention is explained in more detail with reference to the description and the drawings.

Show it:

Fig. 1 Schematic representation of a once-through steam generator, the What serabscheider at the upper end of the combustion chamber wall is arranged on the working side

Fig. 2 Schematic representation as Fig. 1, are arranged on the working side in the convection top heater heating surfaces between the flue gas surround pipe wall for the secondary heating surfaces and the inner wall bore of the flue gas return shafts.

Fig. 1 The working fluid enters the combustion chamber walls 1 and flows through the pipe wall heating surface switched as a steamer from the bottom up.

At the end of the evaporator, the working fluid is fed through the connecting line 7 to the water separator 5 , where water and steam are separated from one another depending on the load. The steam is supplied to the flue gas flue walls 2 connected as superheaters for the secondary heating surfaces through the connecting line 8 which is flowed through from bottom to top. Thereafter, the working fluid (steam) is 3 supplied to the unillustrated flue gas return eye pits and supplied from these non-represented by lines 10 superheater stages or a steam turbine, not shown, through the connection lines 9 wandberohrung the switched as a superheater interior.

Fig. 2 differs from Fig. 1 in that the convection superheater stage 6 on the working fluid side through the lines 11 and 12 between the outlet of the flue gas-surrounding pipe walls 2 for the secondary heating surfaces and the entry of the inner wall pipe 3 of the flue gas return ducts, not shown Connection lines are switched.

Reference list

1 combustion chamber tube walls
2 flue gas duct surround pipe walls for the secondary heating surfaces
3 Inner wall tubing for the flue gas return ducts
5 water separators
6 convection superheater stage / support tubes (bulkhead superheater)
7 connecting lines
8 connecting lines
9 connecting lines
10 connecting lines
11 connecting lines
12 connecting lines

Claims (2)

1. lignite-fired once-through steam generator in a built-in design, in which the combustion chamber tube walls flowed through with working fluid and the flue gas draft surrounding tube walls for the secondary heating surfaces are formed above the combustion chamber in a tube-web-tube version, the steam generator tube walls being openings for the connection of return suction shafts for removing a partial quantity of flue gas, which are provided with an internal wall flow through the working medium, characterized in that in the working medium flow direction the combustion chamber tube walls ( 1 ), water separator ( 5 ), the flue gas surrounding pipe walls ( 2 ) and the inner wall tubes ( 3 ) of the individual flue gas return shafts ( 4 ) are arranged one behind the other on the tool side. 2. lignite-fired once-through steam generator according to claim 1, characterized in that one or more consecutively arranged convection superheater stages ( 6 ) between the flue gas duct pipe walls ( 2 ) and the inner wall tube ( 3 ) of the individual flue gas return shafts ( 4 ) arranged behind one another on the working side are.