Patent US 5,280,756

A method and system for controlling and providing guidance in reducing the level of NO.sub.x emissions based on controllable combustion parameters and model calculations while maintaining satisfactory plant performance and not causing other harmful consequences to the furnace. To implement such a system, boiler control values of flow, pressure, temperature, valve and damper positions in addition to emission sensors for data associated with the production of NO.sub.x, O.sub.2, CO, unburned carbon and fuel. This information is received from standard sensors located throughout a boiler which are connected either to a distributed control system (DCS), or another data acquisition system which is time coordinated with the DCS. The DCS passes this information to a computing device which then processes the information by model based optimization simulation programs, also referred to as the NO.sub.x Emissions Advisor. The presentation of recommendations to the operator consists of a series of graphic displays hierarchically arranged to present the operator with a simple summary that has available more detail support displays at lower levels. The NO.sub.x emissions automation system transmits the recommended positions to the controlling devices including furnace air dampers and coal feeders.