| 摘要 |
A waste gas containing sulfur oxides (SOx) and/or nitrogen oxides (NOx) is purified by leading the waste gas to a radiation irradiation zone, adding ammonia (NH3) to the waste gas before, during or after the irradiation, collecting the resulting by-product (ammonium sulfate and/or ammonium nitrate) by means of a dust collector, and releasing the purified waste gas to the atmosphere. The amount of NH3 to be added is selected so as to be smaller than an amount calculated from target desulfurization and denitrification efficiencies so that it is possible to reduce the leakage of ammonia despite variations in the composition of the waste gas. Further, an alkaline substance exclusive of ammonia is added to the waste gas within the dust collector or at the upstream side thereof so that the pH of the collected by-product is adjusted to 6 or more, preferably 7 or more, thereby suppressing the adverse effects of sulfamic acid impurities.
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