Siemens: Lambda Control As An Early Intervention Method Reduces NOx Emission From Regenerative Glass Tank Furnaces And Saves Energy

In a high degree it decides about energy efficiency and NOx emission and requires advanced control solution.



Keeping NOx-emission below required 500 to 800 mg/Nm³is impossible to reach without continues control about remaining oxygen content in flue gas. It helps to avoid energy losses from uncontrolled air input at the same time. Therefore the side effect of energy saving pays for the Lambda Control and NOx-reduction. Furnace operation with a very low but reliably controlled excess airis a real key point for efficient and low-pollution combustion in the glass tank furnace.



The better the accuracy and stability of Lambda measurement, the closer the operation may be kept to optimum situation. STG Zircon dioxide sensors for high temperature use are installed at the top of regenerator, just downstream of combustion chamber, monitoring in Simatic PCS 7 control system the Oxygen content in flue gas, the real excess air and the amount of inspiration ai. Knowing the fuel composition, the system will give complete flue gas analysis.

After years of development service life of sensors is in a range of 4 to 7 years now, making it possible to get a reliable and accurate measurement, good for automatic control.



Based on reliable sensors, Lambda Controlmeans:

-Minimise inspiration air, which is undesired and causes losses any way

-Compensate any remaining inspiration air, in order to guarantee stable and optimum conditions for combustion



combustionDoing this for regenerative glass tank furnaces in a stable way, requires an intelligent combination of analysis, combustion calculation, feedback oriented and predictive control. There are software blocks for Simatic PCS 7 well proved available, for gas and oil as well as for end port or cross fired furnaces.



The scope of solution includes:

-zircon dioxide lambda sensors

-PCS 7 control system

-Programming and commissioning