Problems with vacuum distillation process
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The last edit to this post was made by A window that won’t close_KEIQ on 2018-8-9 at 17:13. Regarding the issues related to the vacuum distillation process, as shown in the diagram, the negative pressure at the top is set at 47 KPa and the temperature is 80°C; after being cooled by the cooler to 45°C, the liquid enters the reflux tank. The other end of the reflux tank is connected to a vacuum pump. Under these conditions, can the steam at the top pass smoothly through the cooler and into the reflux tank? Are there any requirements regarding the design of the cooler? Can the pressure difference required for the plate exchanger be satisfied?
Forgot to upload it; I’ve edited it again. Thanks for the reminder
I’ve never seen a design of this kind; usually, a cooler has two outlets – the liquid-phase outlet leads into the tank, while the gas-phase outlet leads to the vacuum pump. Moreover, there is definitely a height difference between the tank and the top of the tower; if this difference is greater than 10 meters, gravity alone is usually sufficient for flow to occur.
If I look closely, I can’t figure it out: what is the state of the fluid inside the tube side of this condenser? Is it half liquid and half gas, or is it a piston flow? In the case of pressure reduction, if steam flows through the tube side, the condensation effect isn’t very good, right? Why doesn’t the steam flow through the shell side?
Where is the project location? What is the local atmospheric pressure? For ordinary vacuum pumps, the maximum vacuum level in coastal areas is around -100 kPa, with a normal value of -70 to -80 kPa. To maintain a vacuum level of -47 kPa at the top of the tower, the losses in the heat exchange equipment and pipes need to be kept below 35 kPa. The pressure drop in shell-and-tube heat exchangers is typically 20 to 30 kPa. Plate heat exchangers and plate-fin heat exchangers have higher heat transfer coefficients, usually 3 to 5 times that of shell-and-tube heat exchangers; they also exhibit greater turbulence, which results in a higher pressure drop, typically around 50 kPa
How can I stamp on posts like you do? I want to be able to stamp too! Please reply