Lambda Control based on Oxygen sensors

Taking control about ingressed air

Parasitic air which is not needed for combustion causes energy loss due to an increased waste gas flow and reduces energy efficiency.


O₂ value of STG sensors as basis for Lambda control application		Screenshot Lambda Control in PCS7

STG Oxygen sensors today are representing a wide spread standard in German and European glass industry. Already several melting furnaces are operating more energy efficient with lowered air pollution, using Lambda-Control based on STG sensors.

While ratio control of air and fuel controls only the input, but uncontrolled input of Parasitic air as about 5…10% of total air really decides about efficiency and NOx emission. Only Lambda control may provide you real control of optimum combustion, taking in account the feedback of combustion products.

In response to requirements of NOx reduction, of CO₂ reduction and energy saving, melting furnaces are forced to operate today using greatly reduced amounts of combustion air, even below stochiometric ratio of air and fuel or even using excess reburn gases. STG lambda sensors and STG signal processing are taking in account such trends, making it possible for reliable measurement and control of Parasitic air factor Lambda even for extended low stochiometric operations.

Lambda control – that means:

1 . Measuring flue gas composition downstream just after furnace chamber and monitoring the actual figure of uncontrolled parasitic air infiltration

2. Based on that to minimize air infiltration, which is always reason of energy losses and extended NO formation

3. To compensate changing parasitic air infiltration by modified combustion air input. This has to be done in the way of predictive control due to long response time of such a control loop.