The Impact Of Mass Transfer Effects On The State Of Flow In The Iron Filings Fluidized Bed

Along with the rapid industrial development, China's water resources are vast areas ofpolluted, therefore, an urgent wastewater treatment (particularlly difficult to biodegradate),andnew technologies are needed. Scholars depend on the large number of studies show that thetreatment of iron filings micro-electrolysis method have lower costs, better treatment effect, so,iron filings treatment has been applied. But after operation in a period of time, filler (Iron)surface passive and reduce the number of Fe-C-cell, so that the state of mass transfer becomeworse and the efficiency of treatment is markedly lower.The technology of treatment on Iron filings fluidized bed can solve the problems onoperation, amend the passivation on filler surface, optimize the state of water flow, so that theequipment can be sustained and stable operation.First,through the experiment ,we identified the residence time with air(without air),andthen, study the relationship between the flow of water and the mass transfer effects. Last, wehave the following conclusions:(1)unchanged in the flow velocity, the best reaction time of 14 min with air;(2)unchanged in the flow velocity, the dissolution of iron(total iron concentration)can be quickly reached saturation point;(3)change the flow velocity, mass transfer change depend on flow velocity, the bestvelocity is 0.04cm/s. In laminar flow conditions, with the increased flow velocity, theresistance of mass transfer boundary layer will reduces, so, the greater the flow rate, the better the state of mass transfer. In the turbulent flow,the concentration in a short period of time cancome to balance. With the flow increased, the residence time will shorter, the probability ofwastewater fully access to iron will decrease, dissolution of Fe(total iron concentration)willdecline, so the flux of Fe will decline, and the state of mass transfer will become worse.According fluent simulation, we compare the flux in the experiment and the simulation.Through error analysis , we prove the hypothesis in simulation is rational.