Periodic operation recuperator beds

Flow reversal performance is controlled weakly by the period r. Flow reversal is an autothermal operation and as such exhibits parametric sensitivity. Greater stability can be ensured by the conventional expedient of providing cooling in the catalyst bed. It can also be done through bypassing part of the reactor effluent gas around the recuperator section. 

A flow direction switch occurs at r/2 for a cycle period r set by the plant operator, or it may be initiated by the reactor or recuperator outlet temperature. Startup of the flow-reversal system requires a heating device to bring the catalyst bed or at least the frontal portion up to ignition temperature. This temperature is about 350°C for S02 oxidation using conventional catalysts. 

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