【Q&A Question 056】February 25, 2017
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This post was last edited by 955559 on 2017-7-21 22:00 [Q&A Question No. 056] 2017.02.25: What are the factors that affect the dry point of heavy naphtha? The reference answers will be visible after responding; points are awarded by identifying the key points. (Unless otherwise specified, all questions and answers are based on hydrogenation units.) ) The air weight stone extraction volume is unreasonable ； The amount of material dispensed from the tower top is either too high or too low ； The properties of the feed become lighter or heavier ； Fluctuations in the outlet temperature of the reboiler ； Reboiler core leak ； Fluctuation of the liquid level at the bottom of the tower ； Tower pressure fluctuations ； Changes in reaction conversion rate. 2017 Q&A Summary Thread (updates have begun) http://bbs.hcbbs.com/thread-1657793-1-1.html 2017 Daily Question Summary Thread (updates have begun) http://bbs.hcbbs.com/thread-1657794-1-1.html 2016 Q&A Summary Thread (updates completed) http://bbs.hcbbs.com/thread-1597792-1-1.html Third Round of Haichuan Outstanding Management Members Selection Contest http://bbs.hcbbs.com/thread-1655902-1-1.html (Source: Haichuan Chemicals Forum)
Top temperature, top pressure, reflux ratio, bottom temperature, properties of the feedstock, and catalyst performance (such as the presence of cracking, etc.)
Top of tower temperature, top of tower reflux temperature, top of tower pressure, bottom of tower temperature
The dry point of naphtha is affected by the top temperature and pressure of the tower, the temperature of the feed material entering the tower, changes in the density of the feed material, changes in the flow rate and temperature of the reflow at intermediate stages, changes in the flow rate of side products, the pressure and flow rate of steam supplied to the bottom of the tower, whether the reflow oil from the top of the tower contains water, and the degree of blockage in the tower trays. Too little reflux at the tower top, insufficient internal reflux, and poor distillation efficiency can cause changes in the dry point of naphtha.
1. Top of tower temperature 2. Top of tower reflux temperature, middle section reflux flow rate 3. Top of tower pressure 4. Bottom of tower temperature, bottom of tower steam volume 5. Drawoff amount 6. Reflux amount
The distillation efficiency of the distillation column is poor, due to fluctuations in bottom temperature, column pressure, and the amount of product extracted
The top temperature and pressure, feed temperature, changes in the light and heavy components in the feed, moisture content, amount of stripping steam (if any), middle section reflux temperature and flow rate, amount of product taken from the side streams, whether the top reflux contains water, salt accumulation on the top trays, and whether the amount of top reflux is too low – all of these factors can affect the dry point of naphtha.
Fluctuations in the dry point of heavy naphtha are mainly caused by unstable operation of the distillation tower, which leads to a poorer distillation effect. The extraction amount of heavy naphtha is unreasonable ； The amount of material dispensed from the tower top is either too high or too low ； Fluctuations in the outlet temperature of the reboiler ； Reboiler core leakage ； Fluctuation of the liquid level at the bottom of the tower ； Tower pressure fluctuations ； Furthermore, changes in reaction conversion that result in a lighter or heavier feed composition both lead to fluctuations in the dry point of heavy naphtha.
Fluctuations in the dry point of heavy naphtha are mainly caused by unstable operation of the distillation tower, which leads to a poorer distillation effect. The extraction amount of heavy naphtha is unreasonable ； The amount of material dispensed from the tower top is either too high or too low ； Fluctuations in the outlet temperature of the reboiler ； Reboiler core leakage ； Fluctuation of the liquid level at the bottom of the tower ； Tower pressure fluctuations ； Furthermore, changes in reaction conversion that result in a lighter or heavier feed composition both lead to fluctuations in the dry point of heavy naphtha.
1. As the tower pressure increases, the dry point of naphtha decreases. 2. The reflux at the tower top decreases, causing the dry point of naphtha to rise. 3. Water in the feed stream, fluctuations in the dry point of naphtha. 4. As the feed temperature increases, the dry point of naphtha rises. 5. As the temperature at the bottom of the tower increases, the dry point of naphtha rises as well. 6. Failure of the tower top reflux flow rate or the naphtha extraction volume.
Bottom temperature of tower； Extraction temperature ； Return flow