Solar Turbines Inc.

Alan H Campbell

Thomas E Duffy

John P Archibald

O Leon Lindsey

Control systems (or controllers) for once through, unfired steam generators (or boilers) which control a single parameter--the feedwater flow to the boiler--in accord with an energy or enthalpy balance between the hot gases supplied to the boiler and the steam generated in it. These control systems have a predictive mode of feedwater control and, optionally, an operator selectable, feedback mode to compensate for drifts in the predictive mode. Other corrections may also be made, and predictive and corrective flow splits can be provided to obtain maximum efficiency when the control system is utilized to regulate the operation of a dual pressure boiler.

Steam generator control systems

A compact, unfired, staggered tube, once-through steam generator or boiler of simple construction intended primarily for combined cycle power plants in which the thermal energy utilized to generate steam is obtained from the exhaust gases of a gas turbine engine. The boiler provides steam at two different pressure levels, which maximizes recovery of thermal energy; and all wettable components in the steam/water loop are fabricated of corrosion resistant materials. This eliminates the need for controlling the pH of the feedwater and the need for chemically controlling its dissolved oxygen content, thereby reducing maintenance and operating costs and making automatic, unattended, remotely controlled operation of the boiler practical as well as eliminating the need for blowing down the boiler and minimizing requirements for make-up water. The boiler can be operated dry to remove gas side fouling; and feedwater flow rates can be directly controlled. Orifice-generated pressure drops at the inlets of the boiler tubes which are relatively large compared to the pressure drop in the rest of each tube eliminate the flow instability that is characteristic of once-through boilers.

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Encinitas, CA, United States of America

Alan H Campbell