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.

Abstract: A process control system simulation technique performs real-time simulation of an actual process control network as that network is running within a process plant in a manner that is synchronized with the operation of the actual process control network. This real-time, synchronized simulation system includes a simulation process control network and a process model which are automatically updated periodically during the operation of the actual process control network to reflect changes made to the process control network, as well as to account for changes in the plant itself, i.e., changes which require an updated process model. The disclosed simulation system provides for more readily accessible and usable simulation activities, as the process control network and the process models used within the simulation system are synchronized with and up-to-date with respect to the current process operating conditions.

Abstract: A system for analyzing the impact of operating soot blowers in a heat transfer section of a power plant determines a steam temperature influencing sequence and calculates a feed-forward signal to be applied to a steam temperature control system of the heat transfer section. The system operates a group of soot blowers for a number of times and collects quantitative data related to the steam temperature during and after each soot blowing operation. A computer program used by the system analyzes the quantitative data, generates a number of statistical parameters for evaluating the impact of operating the soot blowers according to a given sequence on the steam temperature, and determines whether the given sequence is a steam temperature influencing sequence.

Abstract: A logic controller includes a memory for storing representations of boolean logic. The boolean logic includes AND and OR boolean logic functions having target values and a plurality of inputs. The processor of the logic controller has input/output circuitry and communications circuitry which provide a plurality of input/output digital logic signals. The processor employs the digital logic signals and solves the boolean logic representations. A firmware routine solves each boolean logic function when the value of any of its inputs is equal to its target value.