Engineering Economics
II-Capital Cost and Estimation Date: 16/09/2016
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Capital Cost and Estimation Contents Components of Capital Cost (CC) Estimation of Fixed Capital Cost (FC) Estimation of Working Capital Cost (WC)
Components of Capital Cost Fixed Capital Investment (the total cost of deg, constructing and installing a plant and the associated modifications needed to prepare the plant site): The inside battery limits (ISBL) investment – the cost of the plant itself (Direct and Indirect costs). The modifications and improvements that must be made to the site infrastructure, known as offsite or OSBL investment. Engineering and construction costs. Contingency charges.
Components of Capital Cost The inside battery limits (ISBL) investment – the cost of procuring and installing all the process equipment that makes up the new plant. It is important to define the ISBL scope carefully, as other project costs are often estimated from ISBL cost. Direct Cost: 1. All the major process equipment, such as vessels, reactors, columns, furnaces, heat exchangers, coolers, pumps, compressors, motors, fans, turbines, filters, centrifuges, driers, etc., including field fabrication and testing if necessary 2. Bulk items, such as piping, valves, wiring, instruments, structures, insulation, paint, lube oils, solvents,
Components of Capital Cost The inside battery limits (ISBL) investment – the cost of procuring and installing all the process equipment that makes up the new plant. Indirect Cost: 1. Construction costs such as construction equipment rental, temporary construction (rigging, trailers, etc.), temporary water and power, construction workshops, etc. 2. Field expenses and services such as field canteens, specialists’ costs, overtime pay, and adverse weather costs. 3. Construction insurance 4. Labor benefits and burdens (social security, workers compensation, etc.) 5. Miscellaneous overhead items such as agent’s fees,
Components of Capital Cost Off-site or OSBL investment – The costs of the additions that must be made to the site infrastructure to accommodate adding a new plant or increasing the capacity of an existing plant. 1. Electric main substations, transformers, switchgear, power lines generation plants, turbine engines, standby generators 2. Power generation plants, turbine engines, standby generators 3. Boilers, steam mains, condensate lines, boiler feed water treatment plant, supply pumps 4. Cooling towers, circulation pumps, cooling water mains, cooling water treatment 5. Water pipes, water demineralization, waste water treatment plant, site drainage and sewers 6. Air separation plants to provide site nitrogen for inert gas,
Components of Capital Cost Off-site or OSBL investment – The costs of the additions that must be made to the site infrastructure to accommodate adding a new plant or increasing the capacity of an existing plant. 7. 8. 9.
Dryers and blowers for instrument air, instrument air lines Pipe bridges, feed and product pipelines Tanker farms, loading facilities, silos, conveyors, docks, warehouses, railroads, lift trucks 10.Laboratories, analytical equipment 11.Offices, canteens, changing rooms, central control rooms 12. Workshops and maintenance facilities 13. Emergency services, firefighting equipment, fire hydrants, medical facilities, etc. 14. Site security, fencing, gatehouses, landscaping
Components of Capital Cost Engineering and construction costs – Home office costs or contractor charges, include the costs of detailed design and other engineering services required to carry out the project. 1. Detailed design engineering of process equipment, piping systems, control systems and offsites, plant layout, drafting, cost engineering, scale models, and civil engineering 2. Procurement of main plant items and bulks 3. Construction supervision and services 4. istrative charges, including engineering supervision, project management, expediting, inspection, travel and living expenses, and home office overheads 5. Bonding 6. Contractor’s profit
Components of Capital Cost Contingency Charges – Extra costs added into the project budget to allow for variation from the cost estimate. 1. 2. 3. 4. 5. 6.
Minor changes in project scope Changes in prices (e.g., prices of steel, copper, catalyst, etc.) Currency fluctuations Labor disputes Subcontractor problems Other unexpected problems
Components of Capital Cost Contingency Charges – Extra costs added into the project budget to allow for variation from the cost estimate. 1. 2. 3. 4. 5. 6.
Minor changes in project scope Changes in prices (e.g., prices of steel, copper, catalyst, etc.) Currency fluctuations Labor disputes Subcontractor problems Other unexpected problems
Components of Capital Costs Working Capital (The additional money needed, above what it cost to build the plant, to start the plant up and run it until it starts earning income) and Estimation: 1. Value of raw material inventory: usually estimated as 2 weeks’ delivered cost of raw materials. 2. Value of product and by-product inventory: estimated as 2 weeks’ cost of production. 3. Cash on hand: estimated as 1 week’s cost of production. 4. s receivable – products shipped but not yet paid for: estimated as 1 month’s cost of production. 5. Credit for s payable – feedstocks, solvents, catalysts, packaging, etc: estimated as 1 month’s delivered cost.
Total Capital Cost Total Capital Cost = Fixed Capital + Working Capital + Land Cost
Land Although Land is a small part of the total capital investment, it should be included. Local chambers of commerce or real estate agents may be able to give information on land costs. In the absence of such data, and for preliminary estimates only, about 3% of the capital investment may be used to estimate land costs.
Estimation of Capital Cost ISBL: Cost of procuring and installing equipment (need to calculate/estimate this)
all
process
Offsite or OSBL: Usually between 20% and 50% of ISBL costs, depending on the project scope and its impact on site infrastructure. Typically, 40% if no details of the site are known. Engineering costs: 10% of ISBL+OSBL costs for larger projects 30% of ISBL+OSBL costs for smaller projects Contingency Charges: 10% of ISBL+OSBL Working Capital: (see previous slide).
OSBL Although typically 40% of ISBL, but…………
Estimation of Capital Cost • A quick capital cost estimate without completing a plant design: Initially ±50% accuracy for preliminary study • The quickest way: Use Cost curve method to scale from known plant For petrochemical process, n=0.7 otherwise it is 0.6 • Economy of scale higher profit for production • Cost
per
unit
of
means higher product
• • •
S is the plants capacities C is ISBL capital cost a=2.775 , n=0.6 (syngas prod.)
a •
Approximate capital cost data for various licensed processes, a rearranged form of previous equation
•
•
Values of the parameters a and n for some fuels and commodity chemical processes are given in Table 7.1 Towler et al. (next slide) These correlations are only valid over a range of plant sizes between Slower and Supper
Estimation of Capital Cost
(2006 U.S. Gulf Coast basis)
Estimation of Capital Cost
Estimation of Capital Cost
Estimation of Capital Cost
Estimation of Capital Cost: If cost data for a similar process are not available • Step Count Method: Need an order-of-magnitude estimate, by adding contributions for different plant sections or functional units. • A functional unit includes all major units needed Includes reaction, separation, or other major unit operation Pump, heaters, are not considered unless they have substantial cost
(USGC Jan, 2010)
Exercise Using Bridgewater’s method, the process for making cyclohexane by saturation of benzene consists of a saturation reactor, and a product stabilizer column. Estimate the cost of a plant that produces 200,000 metric tons per year (200 kMTA) of cyclohexane (assuming that the reactor conversion is 1.0).
Exercise Solution: Using Bridgewater’s method, we have two functional units (the reactor and product stabilizer) and the reactor conversion of 1.0, thus: C = 4320 × 2 × (Q/S)0.675 = 4320 × 2 × (Q)0.675 = 4320 × 2 × (2 × 105)0.675 = $33 MM expressed on a Jan, 2010 USGC basis Using the correlation in Table 7.1, the cost correlation for the Axens process for benzene saturation gives: C = 0.0061 (S)0.6 = 0.0061 (2 × 105)0.6 = $9.2 MM expressed on a Jan, 2006 USGC basis
Estimation of Capital Cost: Other methods • Reverse Engineering Methods: In some situations, a very rough estimate of capital cost can be backed out from operating costs or product prices. Pay-back Method: R
Turnover Ratio Method:
T
Typically 1.0-1.25 simpler, but less accurate
TCOP Method: For large-scale production of formed or assembled components (>500,000 pieces per year)
Purchased Equipment Costs When more design information is available, the cost of a plant can be worked up from the cost of individual items of process equipment. Equipment costs More Exercise derived from computer Estimate programs or websites. the purchased Otherwise, use cost equipment cost of plain equation. carbon steel shell and tube heat exchanger with area 400 size parameters
…………….. Such as
ICARUS™ Technology, Aspen Process Economic Analyzer, www.aacei.org, http://www.aacei.org/resources/. (www.icoste.org)
Estimation of Purchased Equipment Costs
Estimation of Purchased Equipment Costs
Estimation of Purchased Equipment Costs
Purchased Equipment Costs Solution:
�� = 28,000 + (54 × 4001.2) = $99,600
ESTIMATING INSTALLED COSTS: Use Lang factor method Total plant cost and engineering cost. Use Table 7.4 and 7.5 in Towler et al. (based off of carbon steel plant). If we use other material, then we need a Lang factor for it Not a ratio of metal prices* Now use new equation with Table 7.4 and 7.5 based of carbon.
Factorial Method
C = ISBL fixed capital cost of a plant is given as a function of the total purchased equipment cost by the equation: Expansion of above equation for each piece of equipment
CS=carbon steel Piping, equipment erection, electrical work, instrumentation, civil, structures, lagging and insulation
ESTIMATING INSTALLED COSTS Lang’s installation factors: F = 3.1 for solids processing plant F = 4.74 for fluids processing plant F = 3.63 for mixed fluids-solids processing plant
ESTIMATING INSTALLED COSTS
ESTIMATING INSTALLED COSTS
Summary of Factorial Method 1. Estimate the purchased cost of the major equipment items; as before. 2. Calculate the ISBL installed capital cost, using the factors given in Table 7.5 and Table 7.6. 3. Calculate the OSBL, engineering, and contingency costs using the factors given in Table 7.5. 4. The sum of ISBL, OSBL, engineering, and contingency costs is the fixed capital investment. 5. Estimate the working capital as a percentage of the fixed capital investment; 10% to 20% is typical or better, calculate it from the cost of production if this has been estimated—will be explained in next meeting. 6. Add the fixed and working capital to get the total investment required (and land).
Cost Escalation: Relating present cost to past costs.. Indices published in Oil and Gas Journal.
Variation of major cost indices.
Variation of major cost indices relative to 1990 = 1.0.
Cost Escalation: Relating present cost to past costs.. 1. Example: The purchased cost of a shell and tube heat exchanger, carbon shell, 316 stainless steel tubes, heat transfer area 500 m2, was $64,000 in January 2003; estimate the cost in December 2010. Use the M&S Equipment Cost Index. Solution: From Figure 7.2 (or by looking up the index in Chemical Engineering): Index in 2003 = 1123.6 Index in 2011 = 1476.7 So, the estimated cost in December 2010 = $64,000 × 1477/1124 = $84,000. 2. Example: The purchased cost of a distillation column was $136,000 in 2004. Estimate the cost in 2014. Use the Nelson-Farrer index.
Location factor • Most plant and equipment costs are given in U.S. gulf coast (USGC) or Northwest Europe • Otherwise it will depend on fabrication, labor, shipping, import duties etc.
Location factor
Location factor Example: The cost of constructing a 30,000 metric tons per year (30 kMTA) acrolein plant was estimated as $80 million ($80MM) on a 2006 U.S. Gulf Coast basis. What would be the cost in U.S. dollars on a 2006 basis? Solution: From Table 7.7, the 2003 location factor for was 1.11. The exchange rate in 2003 averaged about €1 = $1.15 and in 2006 it averaged about €1 = $1.35. The 2006 location factor for is thus 1.11 × 1.35/1.15 = 1.30 The cost of building the acrolein plant in in 2006 is $80 MM × 1.30 = $104 MM.
A homework to end today’s lecture Adipic acid is used in the manufacture of nylon 6,6. It is made by hydrogenation of phenol to a mixture of cyclohexanol and cyclohexanone (known as KA oil—ketone and alcohol), followed by oxidation with nitric acid. Estimate the fixed capital cost for a 400,000 metric ton per year (400 kMTA) adipic acid plant located in Japan. Solution ISBL capital cost = ………………… (2006 U.S. Gulf Coast basis) ISBL capital cost = ………………… (2010 Japan, see location factor) Then, OSBL capital cost = …………………. Engineering cost and contingency costs = …………………… The total fixed capital cost = ……………………… (2010)