BOILER CONTROL PROVIDING IMPROVED OPERATION WITH FUELS HAVING VARIABLE HEATING VALUES

摘要

BOILER CONTROL PROVIDING IMPROVEDOPERATION WITH FUELS HAVINGVARIABLE HEATING VALUESABSTRACT OF THE DISCLOSUREA boiler control regulates the input fuel and airto satisfy load demand. Simultaneously, the air flow isadjusted by an air flow control to correct for changes infuel heating value by means of a circuit which operates inresponse to outlet steam flow and input mass fuel flow todetermine the difference in presumed heat input and actualheat output and, by inference from the heat imbalance orerror, a change in fuel heating value. The heat error isused to adjust the air flow demand to the air flow control.In another embodiment, boiler heat pickup is derived toremove from the heat imbalance any heat input changes otherthan fuel heating value changes.