Oxygen trimming in coal fired boiler

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Oxygen trimming is a process used in coal-fired boilers to optimize combustion efficiency and reduce emissions. The term "oxygen trimming" refers to the control of the amount of excess oxygen in the combustion process by adjusting the air flow and fuel flow rates.

In a coal-fired boiler, air is typically supplied to the combustion chamber through a series of air registers. The amount of air supplied is typically greater than the amount of oxygen required for complete combustion of the coal. This excess air is referred to as "excess oxygen."

Oxygen trimming involves monitoring the level of oxygen in the flue gas and adjusting the air and fuel flows to maintain the desired level of excess oxygen. By reducing the amount of excess oxygen, combustion efficiency can be improved, which in turn reduces the amount of fuel required to generate a given amount of steam or heat.

In addition to improving combustion efficiency, oxygen trimming can also reduce emissions of nitrogen oxides (NOx), which are formed during high-temperature combustion in the presence of excess oxygen. By reducing the amount of excess oxygen, the peak temperatures in the combustion process are reduced, which can result in lower NOx emissions.

Overall, oxygen trimming is an effective method for optimising combustion efficiency and reducing emissions in coal-fired boilers.

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