Issues regarding the stabilization tower bottom heat source shutdown and the temperature of unqualified gasoline during discharge
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As the title suggests, after a heat source failure causes shutdown, at what temperature below should the discharge of stabilizer bottom gasoline be stopped? What is the reason? Is it simply to prevent the low temperature from causing gasoline to liquefy and leading to damaged float valves in the tanks containing substandard gasoline, or are there other reasons as well? Everyone is welcome to discuss.
Stop the device at 150°C. The reason is that the gasoline delivery line was equipped with liquefied gas, which caused damage to the float valve at the top of the tank containing substandard gasoline. On the other hand, the reason is that the vapor pressure of gasoline does not meet the standards.
OP, I think your reasons are already quite sufficient. Another measure is to reduce the amount of substandard gasoline that is reprocessed, thereby minimizing losses during the transportation of oil products.
This temperature actually depends on the pressure in the stabilizer column; generally, if the column pressure is at 0.8 MPa, there are no major issues above 130 degrees. Low temperatures can lead to high vapor pressure of gasoline, posing storage risks and quality issues in tank areas. At even lower temperatures, the gasoline should be sent directly as crude gasoline from the distillation tower; although its vapor pressure may not meet the requirements, it remains relatively low and stable. This is mainly because the operating pressure in the distillation tower is low, and the conditions are stable. The stabilization system should raise the temperature in cycles and feed material once the conditions are met; adjusting the operations will suffice. Of course, the crude gasoline delivered at this time is still substandard gasoline; production adjustments should be made promptly.
After the heat source is turned off, the pressure in the stabilizer tower decreases as the temperature falls; non-condensable gases are discharged from the overhead reflux tank, which still ensures that the gasoline contains no liquefied gas components and has an appropriate vapor pressure.
In addition to the above, the catalytic operation guidelines state that if the heat source at the bottom of the tower is lost, large amounts of gasoline along with light hydrocarbons will flow into the tank area, which can easily cause damage to the oil tanks. A large amount of light hydrocarbons volatilize into the air, creating an explosive environment that can lead to serious accidents in severe cases. Such incidents have occurred multiple times in catalytic devices, and they must be given serious attention.
Stop the device at 150°C. Additionally, the stabilizer column pressure can be appropriately reduced. Crude gasoline is not fed into the absorption and stabilization system; contact the dispatch to transfer it to a tank designated for unqualified products.
Got it, I'm leaving. . . . . . . . . . . . . . .
Based on operational experience, below 150 degrees, it can be combined with the unqualified line for heavier gasoline. Stabilized gasoline is transported to the tank farm via hydrocarbons; if problems arise, the consequences can be severe.
It cannot be generalized; our system is used to control the saturated vapor pressure of gasoline. The temperature at the bottom of the stabilizer is sometimes kept above 175 degrees, and if it falls below 160 degrees, the vapor pressure becomes significantly unacceptable. This is related to factors such as the pressure at the top of the stabilizer, the load, the temperature at the top of the tower, the amount of cold reflux, and the efficiency of the separation tower. . . . It’s just my humble opinion,