Sugar liquid evaporator with sharp expansion and accelerated flow converging-diverging tubes inserted with twisted leaves

Abstract

The invention relates to a sugar liquid evaporator with sharp expansion and accelerated flow converging-diverging tubes inserted with twisted leaves. The sugar liquid evaporator is characterized in that: the sugar liquid evaporator comprises a cylindrical shell, and an upper steam chamber, an upper tube plate, sharp expansion and accelerated flow converging-diverging tubes inserted with twisted leaves, a central downcomer, a lower tube plate and a lower head which are sequentially arranged in the cylindrical shell, wherein the axis of the central downcomer is coincident with the axis of the cylindrical shell; and the bottom of the lower head is provided with a tube side sugar liquid outlet and a tube side sugar liquid inlet, the top of the upper steam chamber is provided with a tube side secondary steam outlet, and a shell side primary steam inlet and a shell side condensed water outlet are arranged on the cylindrical shell between the upper tube plate and the lower tube plate. By utilizing the local intelligent repeated displacement and the disturbance of periodic converging-diverging rib surfaces and the inserted twisted leaves of the converging-diverging tubes to main flows in the tubes and fluids close to walls of the tubes in the sugar liquid evaporator, the sugar liquid evaporator allows the concentration and the viscosity of the sugar liquid which is on a channel section and is obtained by the flow boiling evaporation under natural convection conditions to be uniformly distributed, the convective heat transfer coefficient and the convective diffusion capability of the fluids in the tubes to be substantially improved, a phenomenon that concentration distributions and concentration distributions of the sugar liquid at central fluid parts and at places close to the walls are not uniform to be improved, and the wall area scale of the sugar liquid to be reduced.

Description

technical field [0001] The invention relates to an evaporator for enhanced heat transfer, in particular to a sugar liquid evaporator using a swirl sheet inserted into a rapidly expanding, accelerating-flow zooming tube. Background technique [0002] There are many kinds of evaporator technologies, such as shell-and-tube evaporators, plate evaporators, evaporators using natural convection or forced convection flow boiling, and evaporators using falling film evaporation. The vast majority of evaporators are traditional smooth tube shell-and-tube evaporators, and the heat transfer method is natural convection or forced convection flow boiling evaporation. The advantages of this evaporator are good mechanical sealing and pressure bearing capacity. High, the seal between the cold and hot sides of the tube side and the shell side is only the welding or expansion joint seal between the tubes at both ends of the tube bundle and the tube sheet, so it can be used in high temperature a...

AI Technical Summary

Problems solved by technology

However, due to the high viscosity of the sugar liquid, the natural convection or forced convection flow boiling evaporation heat transfer operation in the smooth tube evaporator has a very low Reynolds number, and is in the flow state of laminar flow or transition flow. The fluid in the fluid area is difficult to replace each other, and the transfer efficiency of the fluid relying on its own molecular diffusion and heat conduction is very low, resulting in a large difference in the concentration and viscosity distribution of the sugar solution in the central area of ​​the fluid and the near-wall area, which will not only cause the fluid near the wall The flow rate is slow, the heat transfer coefficient is low, and the concentration of the sugar solution near the wall is too high, resulting in serious scaling on the wall.

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