Study On Hydromechanics Of Multitube Distillation Column

Biomass pyrolysis oil is an important new energy, its separation research is under the spotlight by domestic and foreign. This article comparision and analysis the separation method of Biomass pyrolysis oil at present, introduced the research progress of multitube separation equipment, put forward the multitube steam distillation column is an effective method for the separation of Biomass pyrolysis oil. However, a few people have studied this device, especially the property of hydromechanics. This paper study the hydromechanics of the multitube distillation column and obtain the following correlationa formulas and conclusions:(1) The25B,20B,15B type liquid distributors by homemade is very good for liquid distributor, and measure the upper and lower limit operation of liquid flow.(2) The calculation formula of liquid film average thickness is the variable form of Nusselt when flow is layer and laminar; The calculation formula of liquid film average thickness is when flow is turbulent:and measured the coefficient of different flow pattern in various diameter.(3) With the increase of Re,, the liquid volatility gradually increase, the average liquid film thickness gradually thicken as waveform along the tube length. The relationship between liquid film thickness and liquid reynold number is δ=a-bcRel'on a certain site, the coefficient is different in various tube site.(4) The flooding point of tube can use Wallis formula in Gas-Liquid two-phase flow, the state point is depend on diameter,flow rate and fluid property, we obtain the coefficient and fitting formula of different state by experiment correlation. The complete carry up point and flow reversal point have less contact with fluid property, but have much contact with diameter. The amount of inlet air increase when the diameter is increase.(5) The liquid pressure drop almost down to zero in ring film zone; In roll forming region, pressure drop amplitude variation is big, and achieve maximum peak until the intersection point of liquid roll zone; The pressure drop decline slowly in liquid roll zone and stagnation zone, and the pressure drop is increase instead of decrease in all carry up point. The gas flow reduce in air single-phase zone, and the pressure differential curve is similar with the state of increase gas, they have a mutation because of large pressure drop made by initial reverse flow at the critical point of air single-phase flow zone into liquid roll zone.The experimental study in this paper reveal the hypermechanics of multitube distillation column of biomass pyrolysis oil, and provide a reference for future industrial development.