One could ask: Was your primary coke burn interrupted and re-ignited?... one or more times?
You could also check for catalyst channeling by analyzing reactor TI plot readings vrs time, during the coke burn. Compare last regeneration burn pattern with those of previous regens.
Sounds like a typical "Safety in Design" issue.
A way for releiving liquid expansion must be insured. A PRV or procedural. This last at low or no cost.
Procedure must instruct to ALWAYS leave a pathway (be specific) via one of the block valves, left open, for expansion relief. Install a...
As a general practice, condenser efficiency shoud not be set different to 1, as it is a flash operation (V/L equilibrium). The problem you are finding is just as expected.
As far as I know, experts prefer not using tray individual efficiencies. Better to set your model on theo trays. No. of theo...
Linear programming tools help to obtain value of incremental qualities.
PIMS from AspenTech is a powerful stuff... setting up your model is a pretty challenging exercise.
Standard liquid flow is commonly understood at 60 degF and low pressure.
From "Data Book on Hydrocarbons", page 145, we find a chart with a family of curves. Thermal expansion coefficient depends on molal average boiling point.
You divide actual flow over expansion coefficient to obtain flow...
Crudes detailed below seem best suitable for making asphalt.
As you may note, cut points are beyond 700F, which indicates you must feed your topped crude into vacuum distillation. Cold Lake looks best.
Residua converged to 290pen@25C
Crude/Cut point degF/Yield on Crude vol%/Visc cSt@100C
Bow...
As said before, this is highly dependent on crude, depending on asphaltenes content.
For low asphaltenes content, you might get no asphalt specs at all, even at high flash zone temps.
May I ask what is the typical crude you are processing?
Viscosity range ?
You say Flash Point LESS than 270 degC. It shouldn't be an issue.
How to predict Viscosity and Penetration vrs distillation cut point? These are highly dependent on crude type. Crude assay or actual plant data are required for estimating target distillation cut points. Wonder...
Last year story: An incident at a refinery, in California... Loss of containment.
Cause was a pipe section of wrong material at a Vacuum Pipestill bottom. Upon investigation, a CS section was found installed by mistake, where proper alloy should be Cr-Mo (maybe 1.25/0.5 or higher).
Material...
Current practice in my site is to stick a few pieces of scotch tape, radially, along the whole flange face, and over the gasket... Cut long enough pieces of tape.
Clock reference: stick one piece of tape at 12, other sticks at 9 and at 3 if necessary. The same kind of tape you use for gift...
We test the density reading by injecting fresh water for a while. Water temp = typicaly 30F. Expected reading should be very close to 1. This is our reference for setting a correction factor, in the DCS. Correction factor option was cheaper than running a rigorous calibration of the meter...
I installed a Coriolis meter for measuring NaOH injection into a caustic wash system. It works fairly OK.
The solution density-concentration curve is in the process computer, so operators set the injection rate in lbs/hr of pure chemical NaOH. A Math block translate flow and density readings...
Gaskets are specified depending upon process conditions. Catastrophes shall be focused separately.
PR devices have nothing to do with gasket selection.
To mention: Important consideration in plant design is equipment spacing. It has to do with fire events.
Oil industries have their standards...
