atmospheric distillation
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The reflux pump of the atmospheric pressure distillation column stopped for 2 minutes, resulting in an increase in both the temperature and pressure at the bottom and top of the column. The temperature at the top was 82 degrees, with a pressure of 0.027 MPA. This situation persisted for 3 or 4 hours, yet the analysis of the pure methanol remained satisfactory. What’s going on?
OP, will it be qualified in three or four hours? If there is no reflux for a short period of time, it is still possible to meet the standards; but over an extended period, mass and heat transfer in distillation cease to occur – how can it then meet the standards? When the pressure at the top of the tower is 0.027 MPa, the temperature is 82 degrees; it is estimated that moisture has already reached the top of the tower, and in significant amounts!
I think it’s impossible to meet the standards under normal circumstances. Normally, when production is in progress, a large amount of qualified methanol is stored; the substandard products produced over 3-4 hours get mixed in with the qualified products. Besides, testing should not reveal any problems, right?
Yeah, we all thought it was impossible to pass; the tests showed 3 variations, and even the director gave in and told us to check online.
Check whether the total moisture content is decreasing; it’s impossible for this to still meet the standards
After the pump was started, how long did the backflow last?
A 2-minute shutdown of the reflux pump is not a long time; in previous years, our facility often experienced pump failures, and when the valves used to extract pure methanol from the trays were closed, the reflux pump had to stay shut for even longer periods. During normal production, the temperature and pressure in the reflow pump will increase, but it takes time for the heavier components in the distillation section to move upward; therefore, the product obtained by starting the reflow pump in a short period of time is of satisfactory quality.