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Cost Estimation Of Fixed Roof (Cone) Carbon Steel Storage Tanks
15 June 2012
Estimating Cost for process equipment has always been an achilles heel for process engineers including yours truly. Everytime when I was asked to provide budgetary cost for equipment mentioned in a Front End Engineering Design report I used to be red-faced because I just had no idea of how equipment was costed. Fortunately in one or two organizations where I worked there was a procurement and inspection group who knew quite a lot about equipment cost and could provide the data. But there were also occasions where I struggled to find cost data since I had no support of a costing or procurement engineer. Some research on the subject allowed me to find empirical methods of costing some common type of process equipment using empirical correlations. Todays blog entry is related to costing of "Fixed Cone Roof Carbon Steel Storage Tanks". I am presenting the equations below which can be programmed in an excel sheet and which I have already programmed as one. I believe that the cost calculated from the equations described below should be good enough for a +/- 25% budgetary cost. It would be appropriate to mention the references for these equations beforehand and they are as follows:"Estimate Costs of Heat Exchangers and Storage Tanks via Correlations" by Armando B. Corripio, Katherine S. Chrien, and Lawrence B. Evans, Chemical Engineering magazine January 25, 1982.
Base Cost for CS Shop Fabricated tanks
SI Units
CB = EXP(7.994 + 0.6637*lnV - 0.063088*(lnV)2)
where:
CB = Base Cost of the tank, USD
V = Volume in m3, Lower Limit: 5 m3, Upper Limit: 80 m3
USC Units
CB = EXP(2.331 + 1.3673*lnV - 0.063088*(lnV)2)
where:
CB = Base Cost of the tank, USD
V = Volume in US Gallons, Lower Limit: 1,300 gallon, Upper Limit: 21,000 gallon
Base Cost for CS Field-Erected tanks
SI Units
CB = EXP(9.369 - 0.1045*lnV + 0.045355*(lnV)2)
where:
CB = Base Cost of the tank, USD
V = Volume in m3, Lower Limit: 80 m3, Upper Limit: 45,000 m3
USC Units
CB = EXP(11.362 - 0.6104*lnV + 0.045355*(lnV)2)
where:
CB = Base Cost of the tank, USD
V = Volume in US Gallons, Lower Limit: 21,000 gallon, Upper Limit: 11,000,000 gallon
Updated Cost
CB(updated) = CB*(CICY / CIBY)
where:
CB(updated) = Updated Cost of the Tank, USD
CICY = Cost Index, Current Year
CIBY = Cost Index, Base Year
Note: Cost Index (CI) for any year can be obtained form the Chemical Engineering Plant Cost Index (CEPCI) data.
General Notes:
1. Cost of field-erected tanks includes the costs of platforms and ladders but not of foundations and other installation materials (piping, electrical, instrumentation etc.)
2. Cost of shop-fabricated tanks does not include any installation materials including platforms / ladders.
I also plan to put the correlations for costing "Shell & Tube" Heat Exchangers, which are somewhat complex considering the type of head and the tube metallurgy, in my next blog entry. Let me have comments from the members of "Cheresources". Happy reading.
Regards,
Ankur.
Thank you for the information, i just want to add that the process engineer must know a little about the civil engineering and the metal structural in order to know the cost of the investissemnt that we want to do (in order to convice our boss to do or not to do).
Thank you M ANKUR
Best Regards
AYCHI Dhafer