Various embodiments include a method for regulating a burner appliance comprising a combustion chamber, an air supply duct with an actuator to adjust the air supply, and a fuel supply duct with a fuel actuator to adjust the fuel supply. The method comprises: determining the value of the air supply V L; determining the value of an air ratio λ; providing an individual scalar fuel parameter h; calculating the power output P_ist of the appliance based on the air supply V L, the air ratio λ, and the individual scalar fuel parameter h using P_ist=h/λ.Math.V L; and regulating the burner appliance with the fuel actuator and the air actuator until the actual value reaches the target value.

Systems and methods for determining operating discrepancy a process heater. The discrepancy may be identified by solving a fired-systems model of the heater. The fired-systems model is then compared to current operating data. If the sensed current operating data is outside of the expected value(s), as defined by the fired-systems model, the systems and methods may take a remediation action to resolve the discrepancy. The discrepancy may include convection fouling identification and identification of tramp-air leaks within the process heater that are otherwise not easily detected by a human operator.

Systems and methods iteratively solve a fired-systems model of the process heater based on fuel information, a target heat release of the plurality of burners, ambient air information, and available airflow at each of the plurality of burners to identify optimized burner air register settings to achieve a target global excess oxygen level to be sensed by the oxygen sensor. The optimized burner air register settings may be output to a heater controller of the process heater for control of the process heater.

A direct reduction plant is disclosed. The direct reduction plant includes an oxygen injection system, a reformer, and a shaft furnace. The oxygen injection system includes an oxygen injection reactor and a main oxygen burner. The oxygen injection reactor is adapted to receive a gas mixture. The main oxygen burner is adapted to increase a temperature of the gas mixture by burning a mixture of fuel and oxygen fed to the main oxygen burner. The reformer is adapted to reform the gas mixture with the increased temperature. The shaft furnace is adapted to reduce iron ore using the reformed gas mixture.

In a gas hot water heater, changes of the signal output of an A/F sensor are calibrated in the atmosphere, in which the A/F sensor detects an oxygen concentration in a combustion tube. The gas supplied via a gas supply pipe is injected, together with in-taken air, into a combustion tube, which is incorporated in a hot water supply tank, via an injection unit. A proportional valve controls a combustion state in the combustion tube based on the detected oxygen concentration to thereby heat water supplied in the hot water supply tank. A purging process is performed to supply air into the combustion tube, at a timing between an extinguishment operation first performed after the ignition the gas mixture in the combustion tube and a re-ignition operation. Changes of signal output characteristics of the A/F sensor are subject to the calibration after the purging process.

An in-situ averaging combustion analyzer includes a housing and a probe coupled to the housing at a proximal end. The probe has a distal end configured to extend into a flue and contains a zirconia-based oxygen sensing cell proximate the distal end. Electronics are disposed in the housing and are coupled to the zirconia-based oxygen sensing cell. The electronics are configured to measure an electrical characteristic of the zirconia-based oxygen sensing cell and calculate an oxygen concentration value. An averaging conduit is disposed about the probe and has a plurality of inlets spaced at different distances from the distal end of the probe. The averaging conduit has at least one outlet positioned between the distal end and the proximal end of the probe. The electronics are configured to provide an average oxygen concentration output based on the calculated oxygen concentration value.

A burner appliance is disclosed. The burner appliance includes a byproduct sensor in an exhaust flue and/or a barometric pressure sensor to detect an environmental pressure at the burner appliance. By calculating concentrations of combustion byproducts in the exhaust with the byproduct sensor, a controller can adjust blower speed and/or fuel rate to modify combustion efficiency. By calculating the environmental pressure at the burner with the barometric pressure sensor, the controller can adjust blower speed and/or fuel rate to modify combustion efficiency. The barometric-pressure data can also be used to adjust blower speed control bands, thereby calibrating the control bands based on environmental pressure. The environmental pressure can be indicative of altitude and/or weather conditions. Methods of operating said burner appliance are also disclosed.

A method for combustion tuning, comprises collecting exhaust parameters indicating combustion status of a boiler by a sensor array; determining whether the exhaust parameters of the boiler match a preset optimization target; and optimizing combustion, if the exhaust parameters do not match the preset optimization target by selecting a model from a model repository based on a current boiler condition, wherein the model corresponds to a relationship between model input variables and the exhaust parameters; determining at least one optimized model input variable of the boiler for realizing the optimization target, based on the selected model; and adjusting actuators of the boiler according to the optimized model input variable.

The invention is in the field of boiler control and relates to a control method for the operation of a combustion boiler, comprising providing a predetermined upper limit (VF,max) for the flue gas velocity in at least one location of the boiler; monitoring the flue gas velocity (VF) during the combustion of fuel in said at least one location of the boiler; comparing the flue gas velocity (VF) with the predetermined upper limit (VF,max); decreasing the thermal load of the boiler if the flue gas velocity exceeds the predetermined upper limit (VF,max). The invention also relates to a control system configured to execute the control method.

Methods and systems for programming and controlling a control system of a gas valve assembly. The methods and systems include programming a control system in an automated manner to establish an air-fuel ratio based at least in part on a burner firing rate. The established air-fuel ratio may be configured to facilitate meeting a combustion constituent set point of combustion constituents in the combustion exhaust. The methods and systems include controlling operation of a combustion appliance based on closed-loop control techniques and utilizing feedback from a sensor measuring combustion constituents in exhaust from a combustion chamber in the combustion appliance. The combustion constituents on which control of the combustion appliance may be determined include oxygen and/or carbon dioxide.