Abstract
The problem of stand-by operation, although not new on the Pacific coast, is a comparatively new experience for large units operating at pressures above 400 lb and temperatures above 700 F. With combination gas and fuel-oil installations, there are more difficulties to overcome with fuel oil than with gas. The paper describes problems in the control of flame angle when burning fuel oil and developments in high-speed automatic combustion control which make possible the acceptance of emergency loads from 5 to 90 per cent of turbogenerator capacity as fast as the turbine governors can open the control valves. Various operating procedures which have been developed as a necessary routine to meet stand-by conditions are also described. The essential requirements for stand-by and base-load operation are compared. Descriptions are given of actual load-pickup tests on a 1400-lb, 750-F reheat plant and a 425-lb, 750-F plant, and the actual events which take place in the first few seconds of an emergency load pickup are analyzed from the standpoint of what should be provided for in the design of boiler storage capacity, and speed of combustion control. Statistics relating to these features are given for four plants on the Pacific Coast.
