The diesel is black in color, its boiling range is within the acceptable range, and its freezing point is below minus 10; however, adjustments made have not led to any improvement.
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At 1:30 a.m. today, premium fuel samples were taken; the chroma value was 5 and the color was dark. Sampling at the pump outlet (for the diesel pump, before the diesel passes through the crude oil heat exchanger) also showed a dark color. At 10:30 last night, the pressure pump was switched; unit 2 was replaced by unit 3, but since the oil pressure of unit 3 was low, it was switched back to unit 2. It caused pressure fluctuations in the settler for 20 minutes. The pressure then returned to normal. After noticing that the diesel had turned black, increasing the mid-stream circulation rate of the slurry did not yield any improvement. I hope colleagues can analyze the reasons.
1. Do you have diesel reflux? Is it upward reflux or downward reflux? Is the replacement time sufficient? 2. It was caused by an ordinary tower impact – can this be confirmed? 3. Can it be ruled out that there is a problem with the internal components of the tower? Causes the heavy components to be carried along?
There might be a leak in the crude oil pipeline; check that pipeline to see if there are any leaks in the heat exchanger cores
It should be due to overpressure in the tower, caused by a fault in the trays inside the tower.
The pressure fluctuations in the settler affected the pressure in the distillation column; was there any change in the reflux flow of the distillation column at that time? This situation can also occur with short-term tower surges. The poster provided too little data~~~
It’s probably not an internal leak in the heat exchanger, as the sample taken from the side line pump turned black. Check whether there has been any change in the pressure at the top of the tower, to see if this has caused flooding of the tower or if it’s due to mist entrainment.
Bring up the historical trends and compare the changes in the reaction fractionation data; it’s likely that there’s a column flooding issue. If no corresponding changes are observed in the data, check the heat exchanger. It is recommended to change the failure threshold and increase the reflux at the upper part, rather than at the lower part; the key is to replace the middle section.
Reply to 1# zn995210: What is the diesel distillation range? Diesel carbon residue?
Reply to 2# North Gate Snow Removal: Top circulation has never been measured; cold recirculation is being used. The circulation rates of mid-section reflux and slurry reflux remain essentially unchanged. The temperature at the diesel extraction port is between 175 and 182. There are fluctuations, but they are slow. Rule out the possibility of internal leakage in the heat exchanger.
Reply to 7# dugutianzuo5: The top circulation has not been measured for a long time now; cold reflux is being used instead. Last night, the color was still dark; the temperature at the top of the fractionation tower was increased to 112°. There was liquid level in the oil collection tank at the tower top, but the management was concerned that activating the overhead circulation system might contaminate the gasoline, so it was not activated.
Is the top level balance line of your crude oil buffer tank connected to the distillation tower? It’s possible that there is an issue with the crude oil level indicator, which has led to the tank being filled to capacity; as a result, the crude oil ended up in the distillation tower.