Adsorption And Desorption Of Gaseous VOCs By Clover-like Activated Carbon

Catalysts with a cross-section in the shape of clover have a certain degree of industrial application,while clover columnar activated carbon is rare in the market,and its application in the field of adsorption and treatment of VOCs is not popular.Taking clover-like activated carbon as the adsorbent and conventional cylindrical activated carbon with different shapes made under the same material and process as the reference,the adsorption and desorption of VOCs by clover-like activated carbon under environmental conditions was explored,which is an industrial change in the shape of the adsorbent.application to lay a solid foundation.Compare the differences between clover-shaped and cylindrical activated carbons from the perspectives of appearance shape,bed pressure drop,bulk density,etc.;using ethanol,ethyl acetate,and n-hexane as adsorbents,they were fixed on a laboratory-made adsorption device Bed dynamic adsorption experiments were carried out to explore the adsorption performance of clover-shaped activated carbon for ethanol,ethyl acetate and n-hexane at different concentrations,and compared with cylindrical activated carbon.Compared with the cylindrical activated carbon,the clover-shaped activated carbon has grooves on the surface and is densely packed.The same volume of absorber can be filled with more quality of the clover-shaped activated carbon,and the pressure drop of the adsorption column bed filled with the clover-shaped activated carbon is greater.Activate carbon against ethanol in two shapes.The adsorption of ethyl acetate and n-hexane showed that the breakthrough time and saturated adsorption capacity increased with the increase of concentration.The saturated adsorption capacity of ethanol,ethyl acetate and n-hexane by clover-like activated carbon increased by 20%on average.The increase in the saturated adsorption capacity is affected by the concentration,and the increase is not obvious under the action of the strong mass transfer driving force in the low concentration and long-term adsorption and the high concentration,and the saturated adsorption capacity increases obviously at the relative intermediate concentration,which shows that the clover-like activated carbon have a strong adsorption capacity.Shape change has certain application value.The desorption of the ethanol-adsorbed clover-like activated carbon was carried out to explore the effects of space velocity,temperature,and air intake mode on the desorption of the clover-like activated carbon.For the heat transfer of activated carbons,at the space velocity of 3535 h^-1,the temperature outside the desorption column was the highest,and the initial value of the desorption rate was the highest,and the desorption rate reached 92%after 120 min of desorption.The desorption gassed temperature increased,and the desorption effect was better at 150℃.By changing the air intake mode,under the pulsed air intake,the concentration increases sharply in stages,and the gas saving increases the average desorption concentration.The experimental results show that when the nitrogen consumption is reduced by 20%,the desorption efficiency increases by 2%.At 150°C and a space velocity of 3535 h^-1,the desorption of three VOCs,ethanol,ethyl acetate and n-hexane,on clover-like activated carbon was compared,and the results showed that ethanol with smaller molecular weight was easier to desorb.The regeneration performance of the clover-like activated carbon was tested for the same desorption conditions and different desorption conditions,and the results showed that the clover-like activated carbon had better recycle performance.Xylene has a high ozone generation potential and is an important pollutant.In this part of the experiment,xylene was used as the target adsorbate.With reference to the correlation,the breakthrough point was set at 90 mg·m^-3,and the breakthrough adsorption capacity of this point was used as the actual effective adsorption capacity.influence the results show that in the experimental concentration range,the saturated adsorption capacity increases in the increase in the concentration,the adsorption capacity at the breakthrough point first increases and then decreases,and the mass transfer height also decreases with the increase of the concentration.At higher concentrations,the mass transfer zone is thinner but the driving force for mass transfer is greater,the breakthrough time is shortened,and therefore the breakthrough adsorption capacity is reduced.When exploring the effects of bulk density and bed height on the adsorption effect,with the increase of bed height,the penetration adsorption capacity of activated carbon with two shapes increased,the penetration adsorption capacity of clover-shaped activated carbon was larger,and the mass transfer area was thinner,has better adsorption performance.The thermal nitrogen desorption of the xylene adsorbed on the two activated carbons was carried out,and the increase in the bed height was more conducive to the enrichment of xylene.