Method for starting a steam generator comprising a heating gas channel that can be traversed in an approximately horizontal heating gas direction and a steam generator
View Patent ↗The invention relates to a steam generator comprising a heating gas channel, which can be traversed in an approximately horizontal heating gas direction and in which at least one continuous heating surface is located, configured from a number of approximately vertical evaporator tubes, connected in parallel to allow the passage of a flow medium. The aim of the invention is to provide a method for starting a generator, which guarantees a high degree of operational safety, even for a steam generator with a particularly simple construction. According to the invention, to achieve this, at least several evaporator tubes are partially filled to a predeterminable desired level with unevaporated flow medium, prior to the impingement of the heating gas channel by a heating gas.
1. A method for starting a steam generator, comprising:
traversing a heating gas channel with a heating gas in an approximately horizontal heating gas direction;
locating at least one continuous heating surface, configured from a number of approximately vertical evaporator tubes connected in parallel to allow the passage of a flow medium;
partially filling at least several evaporator tubes to a predeterminable desired level with an unevaporated flow medium; and
impinging the heating gas channel by the heating gas,
wherein during a supply of the evaporator tubes with the flow medium, a particular mass flow density is set so that an evaporator tube heated more than a different evaporator tube of the same continuous heating surface has a higher throughput of flow medium than the different evaporator tube.
2. The method in accordance with claim 1 , wherein the level of the unevaporated flow medium in the particular evaporator tubes is determined by a differential pressure measurement between the lower tube inlet and upper tube outlet.
3. The method in accordance with claim 2 , wherein the desired level is specified relative to design starting heating characteristics.
4. The method in accordance with claim 3 , wherein the starting heating characteristics are determined on the basis of characteristic values for the boiler geometry and/or the time characteristics of the heat supply by the heating gas.
5. The method in accordance with claim 4 , wherein a measured value characteristic of a pressure of the flow medium is measured when the heating gas channel is impinged by heating gas, whereby if the measured value exceeds a predeterminable limit, a continuous impingement of the evaporator tubes by unevaporated flow medium takes place.
6. The method in accordance with claim 5 , wherein the supply of flow medium to the evaporator tubes takes place after the onset of steam formation in the evaporator tubes.
7. The method in accordance with claim 6 , wherein the supply of flow medium to the evaporator tubes is controlled in such a way that superheated steam emerges at the upper tube outlet of the one or every evaporator tube.