Cost estimation grass roots

Classification of Estimates There are two broad classes of estimates grass roots and battery limits. Grass-roots estimates include the entire facility, starting with site preparation, buildings and structures, processing equipment, utilities, services, storage facilities, raihoad yards, docks, and plant roads. A battery-limits estimate is one in which an imaginary boundary is drawn around the proposed facihty to be estimated. It is assumed that all materials, utilities, and services are available in the quality and quantity required to manufacture a product. Only costs within the boundary are estimated. 

Multiple-factor methods include the cost contributions for each given activity, which can be added together to give an overall factor. This factor can be used to multiply the total cost of dehvered equipment X (Ce(j)del lo produce an estimate of the total fixed-capital investment either for grass-roots or for battery-hmit plants. The costs may be divided into four groups ... 

IIS estimate the total installed cost for a grass-roots plant producing an organic chemical (S-F process) on a continuous basis. We assume that the total cost of delivered equipment 2, (C )del is 1 million and use suitable factors from Table 9-51. 

A firm is evaluating two competing projects. The first is a new ( grass roots ) inorganic chemicals plant, while the second is the expansion of a textile fibers facility. The process engineers have estimated the projected annual revenue, total capital investment, and total annual cost (without capital recovery) for each project, as follows ... 

Study Basis. - The basis for comparison is a self-sufficient, grass-roots facility producing 14,500 BPSD (barrels per stream day) of a stabilized hydrocarbon product. Table 5 lists the basis for economic assessment. While each facility is self-sufficient as would be expected in a remote location, the cost estimate assumes on-site construction at a U.S. Gulf Coast location. 

The other cost contributions, either as direct or indirect costs, are expressed by means of factors /j relative to the purchasing cost of basic equipment. Table 15.6 presents some mean values, ordered by the type of process fluids, fluids and solids, or solids (Peters Timerhaus, 1991). The reference year is 1990. The factors FI to F9 designate direct costs, while the factors FIO and FI 1 regard indirect costs. The factors F12 and F13 allow the estimation of contractor fees and unforeseen events. The factors F6 to F9 considers only plant extensions and improvement of an existing site, and not grass-root... 

Site development costs, Csj,e, are discussed above in the section on capital investment costs. In lieu of a detailed estimate, which is not normally prepared at this stage of cost estimation, a value of 10-20% of Ctbm may be assigned for a grass-roots plant and 4-6% for an addition to an integrated complex. 

For the depropanizer column, most of the default values are acceptable. Because a single distillation system would be installed normally on an existing plant site, using utilities provided by the site, the Project Type would not be selected as Grass Roots/Clear field. This Project Type would cause new items, already provided at the site, to be included in the design and cost estimates. Typically, these include a new control system and electrical substation components. 

Figure 7 shows the variation of estimated capital cost with production capacity. Capital costs, in this case, are estimated for a self-sufficient, fully integrated, grass-roots plant and are factored estimates based on equipment prices. (Capital and operating costs are provided for conceptual study only. These costs vary considerably depending on location and feedstock type and are therefore only for conceptual purposes.)... 

A comparison of capital cost estimates from the two economic studies that provide such information is given in Table 16-7. The data are given as dollars per million standard cubic feet per day (MMscfd) plant capacity. Results of the two studies are not directly comparable because the Schaack and Chan estimates are based on a grass-roots plant and include such incidental items as heated process buildings for water-based processes, truck loading dock and shelter where needed, and a water well with pump. The Houghton and BucklLn estimates (U.S. dollars) are based on the principal items of equipment only and a more recent time period. 

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