Abstract: A technique of controlling a boiler system such as that used in a power generation plant includes using manipulated variables associated with or control inputs to a reheater section of the boiler system to control the operation of the furnace, and in particular to control the fuel/air mixture provided to the furnace or the fuel to feedwater ratio used in the furnace or boiler. In the case of a once-through boiler type of boiler system, using the burner tilt position, damper position or reheater spray amount to control the fuel/air mixture or the fuel to feedwater flow ratio of the system provides better unit operational efficiency.

Abstract: A method of controlling a power generating unit or other process equipment with a slow reaction time includes creating a feedforward control signal to selectively include a fast response rate component or a slow response rate component based on the average rate at which a load demand set point signal has changed during a particular previous period of time. The method then uses the developed feedforward control signal to control the power generating equipment or other slowly reacting process equipment. In particular, a control method switches between introducing a fast or a slow response component within a feedforward control signal based on whether the change in the load demand set point over a particular period of time in the past (e.g., an average rate of change of the load demand set point signal) is greater than or less than a predetermined threshold. This method is capable of providing a relatively fast control action even if the expected load demand set point change is in a small range.

Abstract: The disclosure is directed to a saturated water spraying system configured to rapidly respond to rapid load changes by implementing a single integrated DCS control block. The integrate DCS control block may include a plurality of process control routines that are necessary to control the operation of the spraying system. For example, upstream and downstream PID control routines may determine and output control variables, and other control routines may be provided as necessary to handle disturbances within a boiler affecting the outlet and spray steam temperatures, and to ensure that the steam temperatures do not fall into the saturation region during operation of the boiler. Because the routines are part of the same control block, the common storage for the control block may be accessed by each of the routines without the necessity of establishing additional communication links for transferring the information as is required when using cascaded function blocks.

Abstract: A method of controlling a power generating unit or other process equipment with a slow reaction time includes creating a feedforward control signal to selectively include a fast response rate component or a slow response rate component based on the average rate at which a load demand set point signal has changed during a particular previous period of time. The method then uses the developed feedforward control signal to control the power generating equipment or other slowly reacting process equipment. In particular, a control method switches between introducing a fast or a slow response component within a feedforward control signal based on whether the change in the load demand set point over a particular period of time in the past (e.g., an average rate of change of the load demand set point signal) is greater than or less than a predetermined threshold. This method is capable of providing a relatively fast control action even if the expected load demand set point change is in a small range.

Abstract: A technique of controlling a boiler system such as that used in a power generation plant includes using manipulated variables associated with or control inputs to a reheater section of the boiler system to control the operation of the furnace, and in particular to control the fuel/air mixture provided to the furnace or the fuel to feedwater ratio used in the furnace or boiler. In the case of a once-through boiler type of boiler system, using the burner tilt position, damper position or reheater spray amount to control the fuel/air mixture or the fuel to feedwater flow ratio of the system provides better unit operational efficiency.