Experimental Studies On Carbon Dioxide Absorption By DBU Solution

The global warming caused by increasing emission of carbon dioxide is one of the most serious environmental problems.Carbon dioxide emission has become the focus of governments and scientists around the world.The fossil fuel power plan is the main stationary sources of the CO2 emission.Therefore,removal of carbon dioxide from fossil fuel power plant flue gases is a key measure to reduce CO2 emission.This article chooses 1,8-diazabicyclo[5,4,0]undec-7-ene(DBU)as a new type of absorbent,and set up a packed scrubber and a spray-packed scrubber to absorb CO2.The performance was evaluated experimentally under various conditions to reveal effects of process parameters,including concentration of DBU solution,DBU flow rate,gas flow rate,inlet CO2 concentration,gas temperature and packing layer height.We also make a comparison with a spray scrubber used before to explore the regularity of DBU solution absorbing CO2.The experimental results show that in the packed scrubber,the concentration of DBU solution is a key parameter and plays an important role on CO2 removal efficiency.When the concentration of DBU solution increased from 1%to 15%,the CO2 removal efficiency increased from 20%to 98%,the CO2 absorption rate increased 4.2 times,and the total volume mass transfer coefficient(KGav)increased 4.7 times.When the DBU flow rate increased from 20 ml/min to 120 mL/min,the CO2 removal efficiency increased from 33%to 94%,the CO2 absorption rate increased 2.8 times,and the KGav increased 2.2 times with the concentration of DBU significantly.With the increase of gas flow rate and inlet CO2 concentration,the CO2 removal efficiency decreases,the CO2 absorption rate and the total volume mass transfer coefficient increases gradually.For the packed scrubber,the suitable operated temperature should be less than 40?.CO2 absorption capacity can reach a maximum under low concentration of DBU solution and normal temperature.When packing layer height increases,it can improve the removal efficiency of CO2,CO2 absorption,CO2 absorption rate to a certain extent,but not the higher the better.The experimental results show that in the spray-packed scrubber,the pall ring packings can absorb CO2 much better than that of the tubular honeycomb fillers under the same experimental conditions.When the concentration of DBU solution increased from 1%to 15%,for the pall ring packings,the CO2 removal efficiency increased from 19%to 96.6%,the CO2 absorption rate increased 4.3 times,and the KGav increased 4 times,for the tubular honeycomb fillers,the CO2 removal efficiency increased from 18%to 42.86%,the CO2 absorption rate increased 1.6 times,and the KGaV increased 1.5 times.When the DBU flow rate increased from 20 ml/min to 120 mL/min,for the pall ring packings,the CO2 removal efficiency increased from 31.29%to 93%,the CO2 absorption rate increased 1.7 times,and the KGav increased 2.3 times,for the tubular honeycomb fillers,the CO2 removal efficiency increased from 21.53%to 48.97%,the CO2 absorption rate increased 1.3 times,and the KGav increased 1.4 times.For the packed scrubber,the suitable operated temperature should be less than 35?.With the increase of gas flow rate and inlet CO2 concentration,the CO2 removal efficiency decreases,the CO2 absorption rate and the total volume mass transfer coefficient increases gradually.CO2 absorption capacity can reach a maximum under low concentration of DBU solution and normal temperature.Compared with the packed-spray scrubber and spray scrubber,the packed scrubber for CO2 absorption by DBU shows superior performance.