Tail-Gas Warmer

Tail-gas warmer Provide first stage of tail gas preheat. 

The mass flowrate of tail gas is known from the overall mass balance, but the tail-gas preheater balance can only be performed if the inlet temperature of the tail gas is known, This must be calculated from the specified design conditions for the absorber, and from the heat exchange at the primary tail-gas warmer. Tail gas leaves the absorber at 10°C (design specification) and it passes through the primary tail-gas warmer where it exchanges heat with the secondary air (for the product-acid bleaching column). The air enters at 232°C and leaves at 80°C. Assuming the tail gas has approximately the same heat capacity as air (a realistic assumption), then ... 

The second exchange in the primary tail-gas warmer is with boiler-feed water. This water enters at 103°C and leaves at 96°C. 

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