Converters Based on Periodic Reversal of the Flow Direction

Development of this type of periodic operation has proceeded primarily at the Russian Academy of Science s Institute of Catalysis in Novosibirsk (Boreskov and Matros, 1984 Matros, 1985,1989). Application to acid production has been discussed many times by Russian authors (see Matros, 1989). 

When ATad 30°C, heat recuperation is important. The outlet switching temperature will be low so the reaction contribution of the inlet and outlet regions is small. In this situation, inert packing with high heat capacity and low porosity can be used in place of catalyst. The variant is shown in Fig. 7. 

Flow reversal performance is controlled weakly by the period t. 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 t/2 for a cycle period t 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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III. S02 Converters Based on Periodic Reversal of the Flow Direction... 

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