Factors affecting the abnormal discharge temperature at the final stage of the two-effect evaporator
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Our company uses a two-effect evaporator to treat alcohol-water mixtures, and there are specific requirements regarding the temperature of the output from the final effect. Recently, the temperature of this output has started to drop and is having difficulty rising. We would like to ask experienced colleagues: what are the factors that can affect the temperature of the output from the final effect?
It is primarily used to separate alcohol from water and other substances. The temperature in the first stage is around 90–95 degrees, with a vacuum level of -0.04. The exit temperature in the second stage is 75 degrees, with a vacuum level of -0.075. The vapor of alcohol and water serves as the heat source for the second stage, allowing for the recovery of another substance； At the moment, the discharge temperature of the second effect is low, and it is difficult for it to increase ； It should be the composition of the feed that changes; it’s not clear which component suddenly increases or decreases
The secondary steam system should be equipped with a non-condensable gas outlet, as non-condensable gases lead to poor heat exchange efficiency!
Does \"non-condensable gas\" refer to air? The impact under negative pressure conditions shouldn’t be that great, right? Seeking guidance from Senior Qi
Analyze the feed material and the components from the first-stage output; it seems that there have been changes in these components
It is necessary to check whether there is a malfunction in the steam nozzles of the first stage, which could cause pressure imbalances and an increased pressure difference between the first and second stages; this in turn leads to a higher temperature in the first stage and a lower temperature in the second stage. Additionally, the temperature can be controlled by adjusting the vacuum level in the second stage
It was likely a change in the material composition; things returned to normal after a few days of operation
The feed composition has changed; there seems to be less alcohol now
Increasing the alcohol content in this case had no effect