Steam generator with a catalytic flue gas treatment during the operation of the steam generator and method

摘要

Two bypass lines (12, 14) are provided between the feed-water inlet line (5) into the economiser (6) of the steam generator and the outlet line (8) from the economiser. The line (12) more remote from the economiser contains a valve (13), preferably a modulating valve, while the bypass line (14) connected closer to the economiser contains a circulation pump (15). If the steam generator is operated in an upper load range from full load down to, for example, 70%, the valve (13) remains closed and the pump (15) is stationary. At lower loads, the pump (15) is allowed to deliver heated feed water from the outlet line (8) to the inlet line (15) and the valve (13) is kept more or less open. In this way, the load-dependent variation of the flue-gas temperature after the economiser is reduced and the operating conditions for a unit, fitted at this location, for catalytic flue-gas treatment are improved. IMAGE