Rho divided by rho is unitless. Multiplying M by a unitless number leaves the units in a mass flow rate basis.
Standard cubic foot is based On 1 cubic foot @ 60F and @ 14.7 psia.
Here is the formula to convert cubic feet to standard cubic feet:
AT = Actual Temp + 460 = Temp. Rankin
AP =...
Can't believe I didn't see this at first
9.5% ethane feed + 0.5% methane + 13.5% propane + remaining C4+s feed
Since the cut between ethane and propane cannot be made perfectly, even in a simulation, the overhead mol% ethane can never get to 95%. (Think if it were ONLY ethane and methane...
After considering this and consulting some of my old textbooks, I think I know how to proceed.
I can get the tower OH pressure from our plant monitoring software, trend it back for a few years, and estimate an average tower pressure. Using anything to give me a hint (lab data, design data...
Try specifying OH temp instead of 95 mol% ethane in the OH. Then toggle the OH temp to manually target the 95 mol% ethane. Also, increasing the reflux rate may help to increase the mol% ethane in the OH.
What simulation software are you using?
Besides the feed stream and OH stream, what else is specified within the system? I would suggest doing a DOF analysis on the system after you determine all the parameters you have specified (depending on the software, this may be done for you).
NGB
Very interesting post! I have heard a bit about this topic here and there, but it never seems to take hold. Are the costs involved in producing ethanol on a commercial scale from coal astronomical? Are there environmental constraints? Or has the idea just not taken hold with mainstream...
A few things:
1) Overestimating moisture content allows me to have an acceptable cushion in regards to this calculation
2) It is my understanding that boiling point is different than dew point
3) Knowing this temperature is useful not only for control, but for identifying where reliability...
I am working in a refinery in the NE and am having trouble remembering how to go about the thermodynamic method of determining the dew point of water in a multi-component stream. I am considering multiple distillation columns that run at a variety of different temperatures and pressures, but...