Abstract: A proportional plus integral plus differential (PID) controller containing an algorithm option is disclosed. The option allows the selection of a classical interacting type of controller or a non-interacting type of controller. The classical interacting type of controller is characterized by the property that tuning any one of the proportional, integral or derivative terms changes the effective value of the other terms. In contrast, the non-interacting type of controller is characterized by the property that tuning any one of the proportional, integral or derivative terms has no effect on the other terms.

Abstract: A system for controlling steam temperature in a boiler using a time delay feedback controller known as a Smith Predictor to provide control tuning of true boiler parameters which change with load.

Abstract: A method of optimizing the scheduling time between sootblowing operations in a boiler having a plurality of heat traps, comprises measuring the instantaneous efficiency for each heat trap of the boiler, using a filter constant and the amount of load under which the heat trap is placed to calculate an average slope for the loss of efficiency between sootblowing operations and calculating an optimum scheduling period between sootblowing operations as a function of a cost factor reflecting the cost of a sootblowing operation, the duration of the sootblowing operation and the slope.

Abstract: A load control for a system comprised of a plurality of energy converters wherein a System Control Signal proportional to system load is developed and utilized to simultaneously adjust the rate of energy conversion of each of the converters in parallel in accordance with changes in system load. The rate of energy conversion for each converter, while operating under stead-state conditions for a predetermined period of time, is readjusted until its actual incremental cost of production is equal to a desired incremental cost.

Abstract: A method and apparatus for breakpoint chlorination is disclosed which utilizes a control dosing of chlorine as well as a base substance and sulfur dioxide to remove ammonia, disinfect and thereafter dechlorinate waste waters. The chlorine dosage is controlled according to a derivative of residual chlorine with respect to chlorine dosage to provide an accurate control of chlorine to insure oxidation of ammonia in the waste water.