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#5255 Uploading Ms Excel Spreadsheets

Posted by Chris Haslego on 18 March 2006 - 05:08 PM

I've noticed that many of you are wanting to share Microsoft Excel files. You can upload them into your messages just like other files. This should simplify the process of sharing the spreadsheets rather than having to email them to one another.

#82070 How About An "in Development" Section In Downloads?

Posted by ankur2061 on 19 January 2014 - 01:14 PM

Sharing your work (calculations / excel workbooks) can be done only with an open heart and a mind free of suspicion.


It is outright hilarious when people claim that the calculation they have created in the form of an excel workbook is their original work. Most of the engineering calculations that we do today have their roots in the physical laws, principles, formuals, and equations developed by pioneers and researchers in the field of engineering and science long before many of us had even understood what engineering calculations are.


People who are developing calculations / excel workbooks are only organizing and representing the work in a proper sequence and in a manner which is easy to understand and present. Yes, it takes time and effort to do this, and those who have undertaken this task need to be appreciated.


I have never endorsed spoon feeding to young engineers because it allows them to think that there is an easy way out for everything. Many of the blog entries in my blog are related to engineering calculations where I have exhorted the engineers to prepare excel workbooks based on the calculation steps mentioned. For each and everyone of these blog entries related to chemical engineering calculations, I have developed an excel calculation workbook, which I have not shared for the very same aforementioned reason.


However, I do want to make a public pledge today. When my eyesight starts betraying me and my hands are no longer able to type on the keyboard of a computer, I would like to donate my entire set of chemical engineering calculation workbooks to "Cheresources" for Chris Haslego to use in a manner he deems fit for the good of the chemical engineering community.




#60483 How About An "in Development" Section In Downloads?

Posted by Chris Haslego on 24 May 2012 - 08:56 AM

I have many, many spreadsheets from visitors that have tons of great information in them, but aren't necessarily ready to be opened and used as they exist. Some may need just a little work, some may need a lot of work. Many of them are well referenced in terms of methodology being used.

However, some people may be working on similar projects and may find these helpful. My hope would be to release them in the Downloads section (clearly marked as "Development Items") and to see if the community can work together to turn these into polished projects.

I thought I'd start by collecting initial feedback on the idea. Let me know what you think. These titles would only be visible to registered members of the community.


#115602 Heat Exchangers, Zone Analysis In Excel With Prode

Posted by PaoloPemi on 20 August 2018 - 09:53 AM

there was a Excel page showing how to calculate properties in different zones I attach a copy, you can examine the VBA code for details,


Prode Properties can export flows or you can calculate from (molar) phase fractions and molar weights of different fractions, see this VBA example


PF = StrLf(Stream)
If (PF > 0.000001) Then ' Liquid present ?
            mw = StrLMw(Stream)
            Cells(rpt + I, 6) = W * PF * mw / mwm ' Liquid Flow


and so on...


you can calculate mixture properties (density, viscosity, thermal conductivity etc.) in different ways,

Prode Properties exposes methods StrGD, StrLD etc. (there are about 300 methods...)

in this Excel VBA example the procedure calculates vapor properties as


            Cells(rpt + I, 14) = StrGMw(Stream)
            Cells(rpt + I, 15) = StrGCp(Stream)
            Cells(rpt + I, 16) = StrZv(Stream)
            Cells(rpt + I, 17) = StrGD(Stream)
            Cells(rpt + I, 18) = StrGV(Stream)
            Cells(rpt + I, 19) = StrGC(Stream)


of course different variants are possible (many methods available),


you can solve many different Flash Operations with Prode Properties, in this case (heat exchanger simulation) the procedure solves a operation with specified P and H but different alternatives are possible



Attached File  htcprops.xls   176.5KB   32 downloads

#111399 Steam To Carbon Ratio

Posted by Flc on 03 October 2017 - 03:38 PM



In syngas plants (ammonia, hydrogen, methanol, etc.) the concepts are different. Steam to dry gas ratio (usually abbreviated as S/DG) is the ratio between molar flow rate of steam and gas, so it's steam flow rate divided dry gas flow rate. This ratio is use frequently at the inlet of shift reactors (HTS, high temperature shift, and LTS, low temperature shift), in particular to evaluate of the flow fed has enough steam as to prevent iron carbide formation in iron-based HTS catalysts.


Steam to carbon ratio is usually used to evaluate the amount of steam at the inlet of a steam reformer, and is the ratio between the steam and the carbon, in mole basis. Consider that C2H6 counts as 2 carbons, C3H8 as 3, etc. E.g. if you have a stream consisting of a mixture of 3000 mol/h of steam, 500 mol/h of C1, and 200 mol/h of C2, ethane counts twice as much (2 carbon moles), so in this case it would be 3000/(500+200*2) = 3.33. In this same case, the S/DG ratio would be simply (3000/700) = 4.28 (though in practice no HTS reactor operates with such a high value).


Theoretically speaking, in the case of a stream consisting of just steam and methane, S/DG and S/C ratio would be the same. In the case of a stream with only steam, methane, and some nitrogen, the S/DG ratio would differ from the S/C ratio. There are some other ratios used, such as the S/C ratio just for hydrocarbons (so you don't consider inorganic compounds such as CO or CO2) or the S/HCC ratio (you just consider HC C2+).


Hope it was clear enough :)


Best regards

#107463 Design Of Distillation Column

Posted by Art Montemayor on 23 January 2017 - 11:57 AM



To learn how to process design a distillation column you can do a variety of things:


  • You can take a first year chemical engineering Unit Operations course in a university that offers such a study;
  • You can purchase and study a book on the subject;  some books are:
    Douglas, James M., Conceptual Design of Chemical Processes, McGraw-Hill, 1988, pp. 453-457.
    Kister, Henry Z., Distillation Design, McGraw-Hill, 1992, pp. 275-282.
    Luyben, William L., "Introduction" in Practical Distillation Control (W.L. Luyben, ed.), Van Nostrand Reinhold, 1992, pp. 10-11.
    McCabe, W.L., J.C. Smith, P. Harriott, Unit Operations of Chemical Engineering, 5th Edition, McGraw-Hill, 1993, pp. 560-568.
    Seader, J.D. and Ernest J. Henley, Separation Process Principles, John Wiley, 1998, pp. 305-312.
  • You can study the material found in many web sites on the internet.  One such site is Dr. Randel Price's (http://facstaff.cbu.edu/rprice/) and a sample of his lecture notes is attached.


Attached File  7-Distillation - Principles.docx   41.13KB   106 downloads

Attached File  8-Distillation II - Modeling.docx   43.81KB   84 downloads

Attached File  9-Distillation III - Operating Equations.docx   51.76KB   75 downloads

Attached File  10-Distillation IV - Calculations.docx   65.62KB   105 downloads

Attached File  11-Distillation V - Ethalpy Balances.docx   39.63KB   72 downloads

Attached File  12-Distillation VI - Enthalpy Concentration Methods.docx   63.35KB   65 downloads

Attached File  13-Distillation VII - Equipment & Column Sizing.docx   56.11KB   101 downloads

Attached File  14-Batch Distillation.docx   45.86KB   71 downloads

#99315 In & Out Breathing Flow Calculations

Posted by ankur2061 on 08 November 2015 - 04:06 AM



Nitrogen flow into the tank will happen during normal inbreathing (pump-out + thermal) and Nitrogen+process vapor mixture will flow out during normal outbreathing (pump-in + thermal).


Nitrogen will not flow in or out only during the following conditions:

1. The tank is in thermal equilibrium with the surrounding atmosphere (no rapid drop or increase in ambient temperature) no pump-in or pumo-out occurs.

2. The Tank is in thermal equilibrium with the surrounding atmosphere (no rapid drop or increase in ambient temperature) and liquid pump-in and liquid pump-out occurs simultaneously at identical volumetric flow rates (highly improbable practical scenario).


Thermal effects are active at locations with large differences between day-night temperatures (diurnal temperature variation) such as high desert areas. Low lying humid areas have the least day-night temperature variation. From this it can be inferred that tanks located in high desert areas with day-night temperature extremes will have more nitrogen consumption compared to low-lying high-humidity regions (sea coast).


Hope this helps.




#88971 Chemical Engineering Plant Cost Index (Cepci)

Posted by breizh on 25 August 2014 - 05:59 PM



Year 2013 : 567.3

Final April 2014 : 573.6

Preliminary May 2014 : 574.4



#114712 Over Flow Line Sizing

Posted by katmar on 02 June 2018 - 03:50 AM

Breizh has pointed you in exactly the right direction. Based on the drawing you have now submitted, I believe that if you follow the link that Breizh gave you, you download Art Montemayor's spreadsheet with the Hills procedure and you follow that logic in your design there is a 99% chance that it will cover everything you need.  If you fall into the 1% that is not covered (because there is other information that you have not explained to us) then follow Breizh's second suggestion and do some searching on this forum and the internet in general.  And if you still have problems then write a post explaining what you have done and what your problem still is.


If you are going to be lazy and follow rules of thumb or ask other engineers to do your work for you, you will never get anywhere.

#114060 Jt Valve In Cryogenic System

Posted by Art Montemayor on 17 April 2018 - 11:16 AM

Syed saqib ahmed:


As usual, Shorty gives an excellent response to your query.

Because this is the Student Forum, we strive to guide and advice students on their studies - rather than their experiences.  For that reason, I would only add for your benefit - as well as for all other students reading this - the following tips, experience, and advice:

  • Return to your basic Thermodynamic studies - whether they be Physical Chemistry, Chemical Engineering Thermo, or other Thermo course you might have or have had and re-read and study again what is discussed in the Thermo theory: Messrs. Joule and Thomson did their studies and work on GASES and not liquids.  The basic Joule-Thomson theory is based on the free, adiabatic expansion of gases and the results generated were on gases.  You are seeking to link the J-T effect with the free expansion of liquids.  That doesn’t work.  It involves another field of study - perhaps linked to J-T, but not the J-T effect.
  • The free, adiabatic expansion of liquids is the basic and primary effect employed in almost all common refrigeration cycles.  This is what drives such refrigeration processes such as ammonia, ethane, propane, ethylene, air, CO2, and all other common refrigerants.  This process may play an important role in your future engineering career and that is why it is important to know the basics and the differences.
  • As Shorty explains, not all gases (including some liquids) cool when expanded freely and adiabatically.  Some well known exceptions are Hydrogen, Helium, and Neon.  Hydrogen gas, especially, heats up and this has been an important experience for me when out in the industrial field.  It is now well known that persons should not get close to high pressure hydrogen piping connections or fittings when out in the field during the daytime.  Any high pressure hydrogen gas leaks will heat up and because of the generated higher temperature and the friction caused, can ignite and cause a bright, almost invisible flame that is not visible in daylight.  I have seen this happen - but only at night time, when the bright, luminous flame appears.  This flame could be a serious hazard during the daytime for anyone passing by.  This, for me, proved the results of Joule and Thomson.
  • In studying your Thermo, note that even gaseous Helium can be liquefied using the J-T effect.  However, it must be below its inversion temperature prior to the free expansion.

#113852 References On Process Diagnosis And Troubleshooting

Posted by Napo on 01 April 2018 - 10:22 AM



Some books are:


- Problem Solving for Process Operators ans Specialist, by J. Bonem (Wiley 2011)

- Process Engineering Problem Solving by J. Bonem (Wiley, 2008)

- Process Plant Design and Operation, by D. Scott and F. Crawley (ICheme, 1994)

- Maintenance of Process Plant, by A. Townsend (IChemE, 1992).



#113611 Peng Robinson Nrtl (Lcvm) With Prode

Posted by marchem on 14 March 2018 - 11:13 AM

with LCVM, Huron-Vidal etc. mixing rules,  Prode Properties utilizes the NRTL (or UNIQUAC, WILSON etc.)  parameters when available, differently, the usual EOS Kij


see this screenshot including both Kij and Aij values




note that calculated values are equal to those calculated with the EOS for all binary pairs where NRTL or Wilson or UNIQUAC values are not defined...


#112409 Calculation Of Required Solvent Rate For Chemical Absorption

Posted by Pilesar on 12 December 2017 - 02:22 PM

You might start with the 'SO2 and Acid Gas Controls' EPA paper https://www3.epa.gov...r1/cs5-2ch1.pdf for a nice overview.

#111748 P&id Number Stenciling On Process Piping

Posted by fallah on 28 October 2017 - 04:53 AM

From a process safety perspective, how important it is to have the piping tag number stencilled on the piping external surface in a process plant?




I think from "piping tag number" you actually mean "line number". If so, it could be useful for line up; but cannot be so sustained and will be removed due to maintenance activities and ambient conditions.  

#111737 Temperature Changing During Mixing 2 Streams

Posted by Bobby Strain on 26 October 2017 - 06:35 PM

But I think the real system will exhibit a lower temperature after mixing. So, be careful where you get advice. Best to find some actual data for confirmation.



#108931 Chemical Engineering Plant Cost Index (Cepci)

Posted by breizh on 04 April 2017 - 04:11 PM

Hi ,

the latest figures

Final DEC 2016 :550.9

Preliminary January 2017 :553


2016 end : 541.7




#103038 Cetane Index

Posted by P.K.Rao on 03 May 2016 - 10:51 PM

The property that governs the performance of diesel  in the engine is Cetane Number. Cetane number is determined with the help of CFR  Cetane Engine. Every country has a minimum specification for Cetane Number for the diesel matketed in their country. If the CN of straight Run diesel  or blend of diesel does not meet the specification, there are additives which can boost CN, like Iso Propyl Nitrate or Iso Amyl Nitrate.

Cetane Index is calculated from ASTM D 86 distillation and density and correlates with CN of diesel not containing cetane improver. Please see ASTM D 4737 Sections 1 and 4.

If cetane improver is added, Cetane Number will increase, but ASTM D 86 distillation and density results will not change. So Cetane Index will remain same as before but Cetane Number will increase because very small quantities of Cetane Imrover are enough  to increase Cetane Number but will not effect distillation and density.

That is the reason why Cetane Index is not effected by addition of Cetane Improver while Cetane Number increases.

#101298 Aspen Flare System Analyzer (Training Material)

Posted by shvet on 22 February 2016 - 10:22 PM

Dear Members,


I am looking for training material for Aspen Flare System Analyzer. If anybody has attended such a training in past conducted by AspenTech or their representatives or in your company, please do share it here. Other useful references / tutorials are also welcome. Really appreciate your cooperation.


Thanks & Best regards, Opel


Get one.

#114227 Isolation Of A Throtlling Valve

Posted by fallah on 30 April 2018 - 06:26 AM



In drainage configuration of the liquefied petroleum gases and hydrocarbon gases the isolation valves (normally ball type) should be located upstream of the globe valve with a minimum distance of 600 mm to avoid stuck open/close of the isolation valve due to J-T effects; but may be applied to all services for simplification and uniformity.