Effects of residence time on the efficiency of desulfurization and denitrification in the bubbling reactor

- Mixed oxidants were analyzed on the removal of SOx and NOx in the bubbling reactor.
- Chemical reaction between gas-liquid phases of bubbling reactor was studied by CFD.
- Spoiler element used in heat transfer area was introduced to the bubbling reactor.
- Spoiler element can both promote the residence time and removal rate of SOx and NOx.

Based on bubbling reactor bottle, experimental study on the absorption of nitric oxide (NO) and sulfur dioxide (SO2) by two mixed liquid oxidants (hydrogen peroxide (H2O2) and sodium persulfate (Na2S2O8)) is performed. Setting the mixed liquid oxidants temperature of 363 K, pH value of 11, mixed gas velocity of 0.3 m3/s, NO and SO2 concentration of 400 ppm, when the liquid level height of the mixed liquid oxidants increasing from 20 mm to 80 mm, the residence time of gas bubble in the bubbling reactor bottle increases from 0.078 s to 0.259 s, with the desulfurization efficiency increasing from 57.31% to 70.15% and the denitrification efficiency increasing from 14.73% to 22.29% respectively. It can be seen that the liquid level height has a decisive effect on the gas residence time, which directly affects the efficiency of desulfurization and denitrification in the bubbling reactor bottle. In order to increase the residence time of gas bubble in the liquid phase under the condition of a certain liquid level height, the spoiler elements (twist tape, helical fin and static mixer) used for heat transfer enhancement in pipe are introduced to the bubbling reactor based on numerical simulation method. The results showed that: different structural parameters of the spoiler elements have a certain role both in promoting the residence time and the efficiency of desulfurization and denitrification in the bubbling reactor.