The L1 project at the Leerdam site maintains a typical end-fired arrangement of furnace including flue gas piping and a downcorner with the flue gas damper. As indicated in the illustrative drawing below, the flue gas recirculation piping is positioned under the port necks.

In between the downcorner and the furnace a cooled refractory damper is used to close the flue gas opening during the OPTIMELT operation when all flue gas passes through the regenerator.

The flue gas exits the furnace through the regenerator which is in heating mode. A small high temperature fan is used to move the majority of the flue gas to the downcorner where it is diluted with air to reach a temperature which is suitable for the downstream flue gas treatment system where a main fan after a baghouse moves the flue gas to the stack.

Once through the OPTIMELT high temperature fan, a small amount of flue gas then recirculates to the opposite regenerator, where it is mixed for reforming with natural gas at the entrance to the regenerator. This mixture is then transformed into syngas and directed through the port neck into the furnace where jets, underneath the port, provide oxygen for combustion.

During this TCR operation the hot flue gas damper inside the downcomer is closed and all flue gas is directed through the TCR system. See the illustration below:

Should the TCR system be unavailable or experience a shutdown, the flue gas damper between the furnace and downcomer is opened and the operation can proceed with the oxy-fuel burners.

A significant part of the OPTIMELT technology development was a comprehensive approach to process and system design safety.

Consequently, by monitoring and controlling the combustion ratio between oxygen and natural gas in the furnace and by continuously measuring the oxygen concentration in the recirculated flue gas, the formation of flammable gas mixture can be prevented. Automatic SIL rated safety shutdowns if necessary.

First Syngas flame (OPTIMELT flame) heated furnace L1 a few days ago!!

Big step forward!!