Forced once-through steam generator

US5529021A · kind A · utility

Assignee

• Siemens Aktiengesellschaft · DE

Inventors

• Axel Butterlin · Bayreuth, DE
• Hermann Dorr · Mülheim an der Ruhr, DE
• Joachim Franke · Koblenzer Straße, DE

Key dates

• Filing date: Nov 4, 1994
• Grant date: Jun 25, 1996
• Expiry date: Nov 4, 2014

Classification

• Technology area (CPC F): Mechanical Engineering; Lighting; Heating
• CPC primary: F22B35/10
• WIPO field: Thermal processes and apparatus
• WIPO sector: Mechanical engineering

Abstract

A forced once-through steam generator with an evaporator heating surface has a control device for a furnace which is controlled by a setpoint value L assigned to the steam generator power and a control device for a feed-water mass flow M into the evaporator heating surface. In order to avoid an overshoot of a specific enthalpy at an outlet of the evaporator heating surface, a device is superimposed on the feedwater control device which serves to derive a variable Q(L1)/,[h.sub.sA (L2)-h.sub.iE) as a setpoint value M.sub.s for the feed-water mass flow. In this case h.sub.iE is the specific enthalpy at an inlet of the evaporator heating surface, Q(L1) is a value derived by a first power value L1 from a function generator for a heat flow into the evaporator heating surface and h.sub.sA (L2) is a setpoint value derived by a second power value L2 from the function generator for the specific enthalpy at the outlet of the evaporator heating surface. L1 is a first power value which is delayed with respect to the setpoint value L assigned to the steam generator power, and L2 is a second power value which is delayed with respect to the first power value L1.