Study On The Effect Rules Of Solid Particles On Gas Dissolution Effect

Gas-liquid-solid multiphase reaction system widely exists in petroleum processing,fine chemical industry and other production processes.The effect of gas-liquid mass transfer on the global reaction rate of multiphase reaction is significant.Studies have shown that after adding particles to a liquid,the gas dissolving effect(dissolved amount and mass transfer coefficient)will change.The effect of particles on the gas dissolving effect is of great significance to global reaction kinetics research,catalyst development,and solvent selection.However,there are few reports about the research methods and effect rules of particles on gas dissolution.In this paper,the research method of gas dissolution effect in the presence of solid particles was established,and the effects of activated carbon,MWCNT,hydrophilic silica and hydrophobic silica particles on the dissolved amount of hydrogen in water and methanol and the volumetric liquid-side mass transfer coefficient were investigated.A three-dimensional unsteady heterogeneous mass transfer model was established based on shuttle effect and permeation theory.The conclusion are as follows:(1)Research method of gas dissolution effect in the presence of solid particles.A measuring device for gas dissolved amount and the volumetric liquid-side mass transfer coefficient was built,and a calculation method for gas dissolved amount and the volumetric liquid-side mass transfer coefficient was established.(2)The effect rules of solid particles on gas dissolution.After adding activated carbon particles in water,with the increase of the content of activated carbon particles in water,the volumetric liquid-side mass transfer coefficient of hydrogen increases rapidly at first and then tends to level,activated carbon particles can increase the volumetric liquid-side mass transfer coefficient by three times,and the equilibrium time can be shortened from 10000 s to 4000 s.When MWCNT particles are added to water,the volumetric liquid-side mass transfer coefficient of hydrogen increases first and then decreases with the increase of MWCNT particle content,the maximum increment of MWCNT to the volumetric liquid-side mass transfer coefficient is 11%,and the equilibrium time is shortened from 10000 s to 8000 s.At the same time,it was found that hydrophilic silica and hydrophobic silica particles had little effect on the volumetric liquid-side mass transfer coefficient of hydrogen-water system;activated carbon,MWCNT,hydrophilic silica and hydrophobic silica particles had little effect on the volumetric liquid-side mass transfer coefficient of hydrogen-methanol system;activated carbon,MWCNT,hydrophilic silica and hydrophobic silica particles have little effect on the dissolved amount of hydrogen in water and methanol.(3)Study on the gas-liquid mass transfer model in the presence of solid particles.Based on the shuttle effect and permeation theory,a three-dimensional unsteady heterogeneous mass transfer model was established,the effects of the distance between the particle and the gas-liquid interface L,the partition coefficient m,the concentration ms and the residence time ? on the enhancement factor E were analyzed.It is found that the enhancement factor decreases with the increase of the distance between the particle and the gas-liquid interface,when the distance between the particle and the gas-liquid interface is more than 2 times of the particle diameter,the enhancement factor is close to 1,and the particle can not enhance the gas-liquid mass transfer coefficient;the enhancement factor increases with the increase of the partition coefficient,and when the partition coefficient is less than 10,the enhancement of the particle to the mass transfer coefficient can be ignored;the enhancement factor increases as the particle concentration increases;the enhancement factor increases first and then decreases as the residence time increases.Compared with the experimental results,the maximum error between the calculated results and the experimental results is 9%,which is in good agreement.