| 摘要 |
<p>PURPOSE:To cause gas-liquid contact reaction and improve the removing efficiency of furfural by causing counter-current contacting of a furfural exhaust gas with an aqueous sodium bisulfite of the specific pH. CONSTITUTION:An exhuast gas contg. furfural is led into a washing tower 2 via a duct 1. On the other hand, an aqueous sodium bisulfite soln. of 4.5-6.5 pH value range stored in a circulating liquid tank 5 is sprayed from nozzles 4 through a pump 6 and a conduit 7, whereby it is caused to make countercurrent contact with the exhaust gas. The aqueous soln. is then returned into the circulating tank and is replenished with sodium bisulfite, after which it is again force-circulated by the pump 6. If necessary, the treated gas is treated in the secondary washing towar of the similar system via a duct 3 and the slightly remaining furfural is passed through an adsorption tower packed with active carbon, whereby it is completely removed. The pollution-free exhaust gas is released into the air. The reason for specifying pH is: At above the upper limit, the absorption efficiency decreases and below the lower limit, a large amount of SO2 gas will be produced.</p> |
