Text: Regardless of where the SCR reactor is located, ductwork from the economizer outlet to the SCR reactor and back to the air preheater inlet must be accommodated.
Entailment: Ductwork from the economizer outlet to the SCR reactor and back to the air preheater inlet must be accommodated, it doesn't matter where the SCR reactor is.
Contradiction: The ductwork from the economizer outlet to the SCR reactor and back doesn't need to be accommodated.