| 摘要 |
PURPOSE:To reduce considerably the consumption of catalysts and to enable the economical operation of a device by exchanging successively the older catalyst layers with fresh catalysts according to the degree of deterioration over the entire part. CONSTITUTION:If the performance of catalysts as a whole deteriorates, a spare catalyst layer 5b is replenished to restore the catalyst performance. Waste gas 3 is passed through catalyst layers 4a, 4b, 4c, 5a, 5b and is thus treated. After the spare catalyst layers 5a, 5b are fully replenished, a prescribed number among the catalyst layers of the longest period of use, for example, the layer 4a, is exchanged with fresh catalysts at every deterioration of the catalyst performance as a whole down to a required lower limit to restore the catalyst performance, then the waste gas 3 is treated in all the catalyst layers 4a, 4b, 4c, 5a, 5b. Thereafter, the catalyst layers are successively exchanged with fresh catalysts in order of 4b, 4c, 5a, 5b, 4a, 4b... so that the discarding of the catalysts from the ones which are used for the longest time and are thoroughly consumed of catalytic activity is made possible. |
