Costs
I/EC
Chemical Package Plant Costs Separate unit or process prices are added together to build up the total cost of a chemical complex
by H. Carl Bauman, American
IN
Cyanamid
THE MONTHS TO COME, m a n y
a
chemical process will be examined but few will be chosen, to p a r a p h r a s e a n old saying. It becomes increasingly important to short-circuit m u c h de tailed calculation to arrive at a reasonably accurate cost for the m a n y alternative schemes which are to be considered before the one most likely to be profitable, is chosen. It is an ironic a n o m a l y that as profit margins shrink, the expense of producing reasonably economic processes rises. M a n y chemical plant complexes are composed of a n u m b e r of units of individual processes. In many cases, one or more such units are repeated often in subsequent proj ects. Cost histories kept in ac cordance with a standard code of
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60 λΟ 40
Company
accounts, prove very valuable in establishing unit cost information which, when properly adjusted, prove most valuable in the quick deter mination of new chemical plant costs. T h e literature contains many ref erences to various chemical process plant costs. T h e reader is often h a n d i c a p p e d , however, by incom plete d a t a defining the basis of cost. These columns have stressed the importance of compiling cost histories in a standard fashion so t h a t this valuable historical information can be used in reasonably accurate determinations of costs of future plants. For uniformity, costs have been shown in these columns on an in stalled basis. This becomes rather important when considering the use
• ^ ^ • • • ^ Η represent range for complete installation, including foundations, basin, pumps, treatment, engineering, overhead, and profit.
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I I I I I I I I I I I represent range for installed cost quoted by manufacturers for towers less foundations, basin and pumps.
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4 6 8 10 12 14 16 18
SIZE OF INSTALLATION G.P.M. X1000 Ranges of cost for chemical plant cooling tower installations ( 8 5 ° F. wet bulb, 3 0 ° F. ΔΤ, 5° F. approach to 75° F. wet bulb, 1 5 ° F. ΔΤ, 1 0 ° F. approach)
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INDUSTRIAL AND ENGINEERING CHEMISTRY
of unit or package plant costs in projecting the costs of a n entire complex. By judiciously adjusting price for size of plant, the expected error in a d d i n g costs of all unit processes to determine total cost of an entire complex, is small. Package plant costs are defined as the turnkey price for the particular unit or process within a battery limit as sumed at a distance of 5 feet from the b o u n d a r y of the installation. To build u p the total cost of a complex requires only the addition of extended costs obtained using d a t a from a compilation similar to the one shown.
The battery limits cost for this plant would be: 150 tons ammonia @ $28,000 per ton
$4,200,000
100 tons nitric acid @ $10,000 per ton
1.000,000
15,000 g.p.m. of cool ing water @ $ 2 0
300,000
1000 tons of ammonia storage @ $60
60,000
500 tons of nitric acid (Sp. G. 1.5) storage @ 90/1.5
30,000
Electrical distribution system @ $70 per kw.
350,000
50,000 l b . of steam @ $3 Interconnecting p i p i n g @ 5% Total battery limit cost
150,000 310,000 $6,400,000
T h e tabic shows the cost per indicated unit capacity for a group of chemical processes a n d most frequently used auxiliaries. The range of capacity for which the unit costs are applicable is also tabu lated. T h e costs for the capacity ranges reflect the m i n i m u m n u m b e r
of units or trains of equipment. For instance, the ammonia plants are based on a maximum of two converters at the 300-ton size. The unit costs, therefore, reflect optimum costs adjusted to 1960 price levels for indicated plants. Space does not permit plotting unit cost against capacity for all the processes shown in the table. How ever, a typical plot would be similar to that shown of the median unit installed costs for industrial cooling towers. Naturally, a full use of the table would require more qualifying data such as: • • • • • • •
Maximum key equipment size Pressure limits Temperature limits Location of plant Feed stock Cost indexes General economic conditions
With a little practice the data in the table can be used to obtain quick approximations of composite plant costs. Cost can be interpolated between the limits from a rough plot on logarithmic paper with sufficient accuracy to give positive indication of the desirability of one of several alternative schemes under study. An example might illustrate the use of this simplified method for rapid plant evaluation. Assume a plant addition for the production of 150 tons of ammonia and 100 tons of nitric acid, requiring 15,000 g.p.m. of cooling water at 80° F . ; 50,000 pounds an hour of 150 p.s.i.g. satu rated steam; 5,000 kw. of elec tricity; 1000 tons of anhydrous ammonia storage; and 500 tons of nitric acid storage. Assuming all other auxiliary facilities—such as administration building, change houses, locker houses, roads, and railroads— common to all schemes are available at the site, the analysis could stop at this point. However, unit costs can also be applied to these facilities. (See I / E C October 1960 for com puting Building Costs and Chemical Engineering Progress, January 1955, for Computation of other Auxiliary facility costs.) Contingencies are not necessary in cost studies of alternatives. In single cases, order of magnitude contingency ranges can be applied to arrive at a probable cost of the facility useful in profita bility studies.
BATTERY LIMITS UNIT INSTALLED COSTS OF TYPICAL PROCESS PACKAGE PLANTS Adjusted
to 1960
Prices
Size Range Daily Tons PROCESS Acetvlene from natural gas (high purity 99+%) Aluminum sulfate(Alum) Ammonia from natural gas Ammonia from blast furnace gas C02 plants Dicyandiamide Maleic anhydride Melamine from dicyan diamide Methanol Nitric acid Oxygen plants Phosphoric acid Sulfuric acid (sulfur burning)
Cost Range Dollars/Tons
100-10 100- 25
90,000-180,000 10,000- 15,000
300-100
20,000- 30,000
300-100 300- 50 100- 20 75- 10
24,000- 40,000 5,000- 9,000 30,000- 75,000 180,000-400,000
150300350200300-
15 25 50 20 50
70,000-140,000 22,000- 40,000 5,000- 12,000 5,000- 18,000 20,000- 30,000
900- 50
2,500- 6,000
AUXILIARIES I Package steam genera tors Large steam generators Refrigeration systems Air conditioning systems Cooling towers Electrical dist. systems CS storage spheres (50 p.s.i.g.) CS storage tanks (atm.) SS storage tanks (atm.)
75,000-10,000 lb./hr. 2.50- 5.00/lb. 300,000-80,000 lb./hr. 4.00-14.00/lb. 1,000- 100 tons 250- 500/ton 1,00050 900-1,350/ton 25,000- 1,000 g.p.m. 1535/gallon 10,000- 1,000 kw. 60- 120/kw. 5,000T5,000T500T-
In the example, the unit for the ammonia plant was selected on the basis of using a single gas compressor and circulator combination, a single synthesis converter, and a minimum of in-process spare pumps. The nitric acid unit is based on a single converter, heat exchanger, and ab sorber line. The cooling towers are assumed to be in 5000-g.p.m. cells, and the steam generator is a package boiler burning natural gas. The plant is located in the southwest region of the country where craft labor productivity is good and labor costs are at U.S. median rates. The general economic picture is com
50 Τ 50 Τ 50 Τ
20- 80/ton (water) 10- 70/ton (water) 90- 240/ton (water)
petitive and therefore contract prices are expected to be good. The unit costs selected can be adjusted up wards or downwards depending on changes in the factors enumerated from the normal estimated in the example.
Our authors like to hear from readers. If you have questions or comments, or both, send them via The Editor, l/EC, 1155 16th Street N.W., Washington 6, D.C. Letters will be forwarded and answered promptly. VOL. 52, N O . 12
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DECEMBER 1960
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