A gas includes a main pipe, a bypass pipe, a gas sensor and a cooler. The main pipe, as an exhaust pipe, discharges exhaust gas generated at combustion of gas fuel. The bypass pipe branches from the main pipe and is set to be smaller in flow rate of the exhaust gas than the main pipe. The gas sensor is arranged in the bypass pipe to detect a gas contained in the exhaust gas. The cooler cools the bypass pipe.

A system and method for heating process air is disclosed. Low NOx burners are provided with low temperature combustion air, e.g., less than about 0° C., and fuel at varying amounts to maintain a desired balance between low NO.sub.2 and low CO emissions. The amount of combustion air and the amount of fuel may be adjusted to achieve desired low NO.sub.2 and low CO via a feedback control system.

Combustion heater control systems and methods that include dynamic safety settings. Current operating parameters of the combustion heater are sensed at a plurality of time intervals and converted into a time-varying signal. The time-varying signal is compared to a burner stability envelope indicating when a burner is likely to enter an unstable state. The unstable state may include huffing, flashback, and/or liftoff. When the burner is likely to enter an unstable state, the combustion heater is controlled to prevent the unstable state.

Systems and methods operate to infer a fuel composition in a combustion system. The fuel composition may be inferred by receiving measured operating parameters including one or more of fuel data defining fuel characteristics used in combustion within a heater of the combustion system, emissions data defining emission gasses exiting the heater, airflow data defining ambient air being supplied to the heater and airflow rate of the air within the heater. One or more relationships within the measured operating parameters may be identified that result in a list of potential fuel compositions. One of the potential fuel compositions from the list may be selected having sufficient likelihood of resulting in the measured operating parameters as an inferred fuel composition. The output the inferred fuel composition to a heater controller of the combustion system and used for automatic control thereof.

Emissions of NO.sub.X and/or CO are reduced at the stack by systems and methods wherein a primary fuel is thoroughly mixed with a specific range of excess combustion air. The primary fuel-air mixture is then discharged and anchored within a combustion chamber of a burner. Further, the systems and methods provide for dynamically controlling NO.sub.X content in emissions from a furnace by adjusting the flow of primary fuel and of a secondary stage fuel, and in some cases controlling the amount or placement of combustion air into the furnace.

A combustion device includes an ammonia supply unit supplying primary reduction ammonia as a nitrogen oxide reducing agent into a combustor and mixing secondary reduction ammonia with combustion exhaust gas discharged from the combustor to reduce nitrogen oxide contained in the combustion exhaust gas and a controller configured to control at least one of the amount of supply of the primary reduction ammonia and the amount of mixing of the secondary reduction ammonia with the combustion exhaust gas in accordance with concentrations of residual nitrogen oxide and residual ammonia contained in the combustion exhaust gas after being discharged from the combustor.

A boiler coal saving control method includes a linear relation model creating step, an optimization target determination step, and a machine learning step. The linear relation model creating step includes creating a multi-grade model grading mechanism and creating linear relation models accordingly so as to fill an empty set in a data set. The multi-grade model grading mechanism includes performing primary grading based on boiler load, coal quality, and ambient temperature, and secondary grading based on boiler load. The optimization target determination step includes determining a boiler optimization target that includes boiler combustion efficiency and a nitrate concentration control value for flue gas. The machine learning step performs machine learning according to a data source and includes a model numbering sub-step, an ontology determination sub-step, and a target optimization sub-step. The control method uses machine learning to provide an operation recommendation for improving boiler combustion efficiency and thereby saving coal.

Systems and methods for reducing NO.sub.x and CO emissions in a natural draft heater are disclosed. For example, the disclosure provides embodiments of systems and methods for controlling a draft value within a heater shell to deliver an amount of excess air to a burner to thereby maintain at least one of NO.sub.x emissions not exceeding 0.025 lb/MMBtu (HHV) and CO emissions not exceeding 0.01 lb/MMBtu (HHV) in a natural draft heater.

The present invention relates to a method of optimization for continuous combustion systems, which reduces fuel consumption, exhaust emissions and particulate matter. The operating principle is based on the introduction of small amounts of hydrogen in the fuel intake duct of the system, or preferably along the continuous burning chamber, with the aim of optimizing the burning of traditional fuels, improving the parameters of the combustion reaction, the effect of the process in question will increase the temperature of the walls of the chamber, ensuring re-ignition and a more complete combustion and consequently reducing the required fuel flow feed. This optimized combustion will increase the combustion efficiency and reduce its environmental impact.

A method for operating a combustion chamber is provided. The method includes obtaining a carbon monoxide reading at an exit of the combustion chamber via a carbon monoxide sensor, and deriving an oxygen set point trim based at least in part on the carbon monoxide reading and a carbon monoxide set point via a controller. The method further includes determining a stability status of the combustion chamber via a combustion stability sensor, and adjusting an oxygen set point of the combustion chamber with the oxygen set point trim based at least in part on the stability status via the controller. The oxygen set point defines a desired oxygen level at the exit of the combustion chamber.