Issues regarding the initial boiling point and saturated vapor pressure of alkylated oils
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Our workshop is a newly established alkylation unit that uses the alkylation process package developed by the China Institute of Petroleum. Recently, the workshop required that the initial boiling point of the alkylated oil be no lower than 30, with the saturated vapor pressure to be controlled within the range of 51–59. After more than a week of adjustments, it was found that as the saturated vapor pressure increased in the analysis of the alkylated oil, the initial boiling point became below the required level (below 30); conversely, when the initial boiling point met the requirements, the saturated vapor pressure was outside the specified range (between 40–49). We generally use the low temperature from the n-butane removal tower to control the initial boiling point, and the top pressure to control the saturated vapor pressure. However, it seems that a balance between these two cannot always be achieved (i.e., both criteria cannot be met simultaneously); I hope the experts on this forum can provide some guidance. Thank you! Thank you! Thank you! Thank you! Thank you! Thank you! Thank you! Thank you! Thank you!
What are your specific operational parameters? The bottom temperature and the amount of product collected at the top are inversely proportional to the vapor pressure. With fine adjustments to the parameters, a situation like the one you described should not occur. Also, it’s worth checking whether the vapor pressure measuring instrument used has been adjusted for atmospheric pressure
We ensure that the tower pressure remains constant by using low-temperature control; that’s how we manage it!
Is the vapor pressure measurement done manually or automatically? If it’s automatic, it needs to be calibrated; it’s the type that operates on its own. Attention also needs to be paid to the sampling vessels and the cooling temperature. A small, fully automatic model like the Haier Chao would be better
The specific operating parameters for our n-butane distillation column are: top pressure of 0.36, top temperature of 47.1 degrees, reflux rate of 11 T/H, bottom temperature of 140 degrees, and bottom pressure of 0.38. We haven’t conducted any analyses yet; regarding the instrument issues you mentioned, we’ll go and check them! Thank you, expert!
What is your base temperature? ? What is the pressure? ?
There is no need to keep the temperature so high. Even if the butane removal column operates at full capacity and thus carries some isobutane, the n-butane removal column does not require such high bottom temperatures or pressures; a bottom temperature of around 115 degrees and a top pressure of 3 kilograms are more than sufficient to meet your requirements. Or is it because of the design specifications of your columns?
We control the saturated vapor pressure at 43–49; the initial distillation point is maintained at around 32. The column pressure is 0.34, and the low-temperature level is approximately 132. When the column pressure remains unchanged, only the bottom temperature changes
The saturated vapor pressure is 50-59; the initial boiling point is definitely above 30. How can the initial boiling point be low when the vapor pressure is 40-49? You can try adjusting only the vapor pressure, making adjustments to temperature and pressure as suggested in previous replies
Our n-butane distillation column is designed with 30 trays and a height of 32.6 meters.