Basics of Steady State and Dynamic simulations

Steady State and dynamic simulation.

General Terms:
In simple words the number of input variables will be more in dynamic Simulation means more data is required to work with dynamics.
Dynamic simulation needs equipment dimensions(Length,Diameter,Weight etc).where as in steady state it is not required.
In dynamics hold ups will come in to picture.where as in steady it is not required.
Eg: The bottom pressure in vessel varies with liquid level in tank.
Dynamics is used for detailed engineering works , OTS works etc. Steady state is for basic engineering studies and will be utilized as a base of detail studies in dynamics.
Steady state is a snapshot of plant where as dynamics is a movie of plant.

Products:
Available software's in market for steady state simulation - PRO/II
Available software's in market for dynamic state simulation - DYNSIM,OMEGA VM.
There are software which have capability to work with both steady state and dynamic state.

There is one more category of simulators available in market is data reconciliation means it  corrects the data and utilizes for optimization. can be more useful in yield accounting.
Eg: ROMEO

Modeling:
In dynamic simulator we look for one steady state condition and few parameters which will be obtained from steady state simulator are very useful for dynamic modeling. Eg: overall heat transfer coefficient values of Heat ex-changers.

Mathematically:
Dynamic simulators contains ordinary differential equations in there solvers and it doesn't mean that steady state simulators wont have differential equations but in steady they force them to "0".

RVP-Ried Vapor Pressure

Refinery Inspection Properties - Part 3

Some acronyms which are related to RVP.
RVP- Ried Vapor Pressure.
TVP-True Vapor Pressure.
ASTM methods(Wet,Dry)- Defined propcedure to calculate RVP.

Very important property where petroleum industries regularly update the values based on seasons as it is a measure of absolute vapor pressure.
In winter season - Need higher values of vapor pressure as it may clog because of condensation will happen.
In Summer - in similar way to avoid vapor lock in summer season RVP values are in lower levels.

This is a labaroary method which is tested in a bomb like structure containing two chambers. in one chamber sample to be tested is used in another propably air the ratio is 1:5 , 1 part of sample and 5 parts of air.

How to relate with simulation(1:5 parts of sample(1 atm) and air(vacuum)), laydown two sources one containing sample and another containing air. mix the two streams from source 1 and source2 using mixer(m1) and try to calculate the out put stream(s3) properties.
Try different options on slecting different sources other than air and sample and see how out put s3 is varying.
In lab source1 might be in one chamber and source2 in another.


Reid vapor pressure is always measured in Psi and it is less than TVP(True vapor pressure).

Note: This is just written based on my experience in simulation field.

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