| 摘要 |
In a method for feed water control in waste heat steam generators, in particular drum boilers with a circulating pump (9) and drum boilers with natural circulation employed in combination power plants, wherein, by a three-component control by means of a superordinated level regulator (13) and a flow-through regulator (14) subordinated to the level regulator (13), the set value (Sin) of the flow-through regulator (14) is displaced by the level regulator (13) in such a way that the level in the drum (6) is always regulated to the set value (S), regardless of interfering effects, the flow-through regulator (14) for the feed water flow (+E,dot m+EE s) is guided by the heat amount (+E,dot Q+EE AG) in the exhaust gas flow. The output signal of the flow-through regulator (14) for the feed water flow (ms) is limited, wherein as the function of the heat amount (+E,dot Q+EE AG) in the exhaust gas flow a selection is made between a limit value (+E,dot m+EE 1) for the start-up operation and a limit value (+E,dot m+EE 2) for normal control operation and the switch from (+E,dot m+EE 1) to (+E,dot m+EE 2) takes place via a time function element (16) with an idle time (T).
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