Causes of bumping during vacuum evaporation concentration
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We concentrate the sugar solution using forced circulation at a vacuum pressure of 0.01 MPa; when the concentration of the solution is high, sudden boiling occurs, and the sugar solution splashes against the walls of the evaporation separator where it crystallizes. We suspect that the circulation circuit becomes smaller, causing the liquid circulating in the heating chamber to overheat; upon entering the evaporation separator, it suddenly flashes – undergoes boiling – and crystals are formed. I would appreciate it if colleagues with experience in evaporation concentration could help analyze the causes of boiling over during vacuum evaporation concentration. Thank you
When the concentration is high, the viscosity increases, and the mixing effect deteriorates; as a result, boiling over occurs under high-heat conditions. I have encountered many such examples. If the original poster has conducted experiments, they will have observed this phenomenon: when there is a lot of sticky liquid in the flask, heating it causes it to explode in small bursts, one after another.
Is the poster using single-effect evaporation concentration? Is 0.01 MPa a vacuum? The specific causes have not been analyzed; I have been working in the glucose and fructose industry for 4 years, during which multi-effect vacuum concentration has been used throughout. If a single-effect system is used, it is recommended to install a foam catcher or an air agitation device in the evaporation chamber.
It’s similar to the principle of boiling over in heavy oil
Reply to 2# hao21100112: So how can this kind of bumping be resolved? ?
The liquid inside is not pure; for example, it contains a large amount of solvent. Controlling the heating rate will solve it
Reply to 5# Mufeng: I don’t think there’s a better solution. You work with sugars, while we deal with chemical products; when we encounter such problems, we resolve them by adding a solvent.
You can try evaporation enhancers or high-salt degumming agents