The Excess Force In The Treatment Of High Concentration Of Nitrogen Oxides

The necessity of technology treatment improvement of high concentration nitrogen oxides was pointed out based on summarized control methods of nitrogen oxides, and operating principle, eminent characteristics and applications at home and abroad of high gravity technology was briefly introduced in this paper. Based on development absorption machine, the rotating packed bed(RPB) was put forward. RPB can be used to increase the efficiency of the absorbent treatment of nitrogen oxides, reduce the costs of treatment and reach the state discharging standards due to its advanced characteristics.A series of experiments were carried out using RPB as absorbing equipment and high concentration nitrogen oxides tail gas as gas source.Mass-transfer process of nitrogen oxides was detail analyzed. Taking packing elementary volume as the research object, the nitrogen oxides mass-transfer model of cross-flow rotating packed bed was deduced according to the suitable assumption. The average absolute error was 8.96%. The mass transfer coefficient of this RPB was more than 480 of the sieve tray tower which used in factory.Based on analyzed absorbing mechanisms of nitrogen oxides, the treatment situation and the effects of gas flow, liquid gas ratio, high gravity factors on absorptivity were investigated. The results show that absorptivity of single stage could amount to 63.7% at a gas flow rate of 2 m3·h-1, liquid gas ratio of 20 L·m-3, high gravity factors of 90, equally 95.6% to theoretical absorptivity. By analyzing absorption mechanism of nitrogen oxides, it showed that RPB was adopt to treatment high concentration nitrogen oxides. After treated by double stages and increased oxidation device, it could reached higher absorptivity.After initial experiment, NaOH solution and (NH2)2CO/ additives were used as intensification absorbent; the effects of gas flow, liquid gas ratio, high gravity factors and concentration of absorbent were investigated. The absorptivity could amount to 80% and 85% at the best operation parameters. The average absorptivity increased about 25% compare with water as absorbent. (NH2)2CO/ additives was used as absorbent on pilot test. After continual operation for 30d and 8h/d by two stages, the average absorptivity higher than 96% and the system operated stably.