Costs plant

The most commonly used index is the chemical engineering plant cost index published in Chemical Engineering Magazine. 

Pilot plant costs range from 10,000 to 10,000,000, but the majority are typically in the range of 50,000 to 250,000, assuming an existing facihty is available to house them. There are three basic methods for estimating the costs to design and constmct a pilot plant similarity, cost ratios, and detailed labor and materials. 

Table 4. Pilot-Plant Cost Estimating Techniques...

W. D. Downey and P. O Rouke, Retail Fertiliser Plant Costs Efficiemy and Proftability, Department of Agricultural Economics, Purdue University, Lafayette, Ind, Apr. 1976. 

Air coolers almost invariably add considerably to plant cost, but they are competitive in operating cost based on direct once-through use of water that requites no treatment. If the alternative to air coolers is the use of water that requites substantial treatment or pumping costs, the air coolers will cost less to operate. 

The accuracy of such cost extrapolation tends to decrease with the length of time involved. Various important U.S. cost indexes are the M S Index, CE Plant Cost Index, Nelson Constmction Cost Index, and the ENR Constmction Index. Similar indexes are available for other countries. 

Year M S Equipment Cost Index CE Plant Cost Index... 

The CE Plant Cost Index (7) is also pubHshed monthly in the Chemical Engineering]omaci A. Index values are given for various categories of equipment, installation, labor, building, and supervision, as well as a composite plant cost index. The composite index for complete plant costs, tabulated in Table 1, is frequentiy used for the translation of purchased equipment costs, even though the equipment component of the index would be better. 

Land cost, a part of the direct plant cost, is placed in a separate capital category because it is not depreciable. Land cost is site-specific and highly variable. 

As an example, the battery-limits capital cost can be estimated for the production of 10,000 t/yr of ethylene (qv) from ethanol (11). Seven processing blocks, ie, vaporizer, reactor, water quench, compressor, dryer, distillation, and energy recovery, can be identified. The highest temperature is 350°C (reactor), and the highest pressure is about 1.7 MPa (17 atm) (compressor, two towers). If a materials-pressure factor, + of 1.03 is assumed, then for N = 7 0 = 0.87 1/0 = 1 64 and f =0 K = 6.3. This gives the 1981 cost as 4.4 X 10 . The 1991 battery-Hmits investment can be obtained, by updating with the CE Plant Cost Index, as 5.3 x 10 . ... 

Table 9-42 presents information on some cost indices for the United States. Engineering News-Record updates its construction-cost index in March, June, September, and December. The Oil and Gas Journal gives the Nelson-Farrar refinery indices in the first issue of each quarter. The Chemical Engineering plant-cost index and Marshall and Swift equipment-cost index are given in each issue of the pubhcation Chemical Engineering. Derivation of the base values is referred to in the respective publications. 

Table 9-43 is based on the method suggested by J. Gran [Eng. Process Econ., 2, 89-90 (1977)]. He showed that reasonably accurate plant-cost indices for various countries could be derived by using two component indices in the equation... 

Typical values for single factors/for batteiy-limit-plant costs (for a carbon steel plant including auxiliaries but not land) are as follows ... 

Piping Estimation The cost of fabrication and installation of process-plant piping appears to range from 18 to 61 percent of the FOB equipment cost as indicated in Table 9-56. This would normally represent about 7 to 15 percent of the installed plant cost and is obviously a significant item. The various available piping-estimation methods are as follows ... 

Electrical and Instrumentation Estimation These costs usually range from 4 to 10 percent of the total installed plant cost, with a median value of about 7.5 percent. As with piping estimation, the process design must be almost completed before detailed drawings and specifications can be prepared for estimating purposes. However, actual elec trical costs can be up to 100 percent higher than estimated costs, and so it is important to attempt to maintain the accuracy range within reasonable hmits. 

Factored electrical cost as a percentage of total installed plant cost for specific types of plant... 

TABLE 9-59 Electrical and Instrumentation as Percentage of Total Installed Plant Cost... 

Complete Plant Costs It is difficult to compare costs of domestic and overseas plants owing to the wide variation in types of plants and sizes and the rapid changes in technology. Useful data are scarce, and the following comparisons must be used with caution and then only for order-of-magnitude estimates of fixed-capital costs. 

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