Furnace control method
AssigneeSterling Drug Inc.
InventorFrederick M. Lewis
Life of this patent
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Abstract
A method for controlling two-stage combustion furnaces having a first stage operated with sub-stoichiometric airflow and a second stage operated with excess air, whereby the first stage airflow is controlled such that the ratio of first stage airflow to total airflow is maintained less than ##EQU1## where N lies between zero and unity.
Claims5
In an incineration process in a two-stage starved air combustion furnace wherein combustible material to be processed is partially combusted with primary air at substoichiometric rates in a first stage to produce gases which are combusted with a controlled superstoichiometric rate of secondary air in a second stage and discharged as flue gases, the improvement comprising the steps of:
- a. determining the rates of primary airflow to said first stage and secondary airflow to said second stage;
- b. measuring the oxygen concentration in said flue gases from said second stage;
- c. determining the Percent Excess Air to Furnace from said measured oxygen concentration;
- and
- d. controlling said rate of said primary airflow in response to said determined rates of primary and secondary airflow and said Percent Excess Air to Furnace, to maintain the ratio of primary airflow to total airflow rate less than a predetermined value of ##EQU6## where N is a number between 0.2 and 0.95 to maintain said primary airflow at a substoichinmetric rate.
Dependencies are inferred from the claim text.