Cost estimation rapid methods

Exponential Methods Rapid capital-cost estimates can be made by using capacity-ratio exponents based on existing cost data of a company or drawn from pubhshed correlations. 

Table 2.1, which corresponds to Figvue 2.3, outlines a rapid method of estimating the production cost of a chemical using numerical factors given by Winter [1] and Humphreys [5]. These factors are only approximate, and they will vary with the type of process considered. They are useful, however, for preliminary estimates. Most companies will have their own factors that are specific for their processes. 

There are several depreciation methods, which are discussed in many economic tercts. Since we want to develop a rapid method of estimating the production cost, we will use the simple linear depreciation method. For this method, divide the difference of the depreciable capital cost and its salvage value by the Ufe of the plant, as shown in Table 2.1. An entire plant or individual equipment has three lives an economic life, a physical life, and a tax life. The economic hfe occurs when a plant becomes obsolete, a physical hfe when a plant becomes too costly to maintain, and a tax life, which is fixed by the government. The plant life is usually ten to twenty years. The depreciable capital cost includes all the costs incurred in building a plant up to the point where the plant is ready to produce, except land and site-development costs. Care must be taken not to include costs that are not depreciable. 

RAPID CAPITAL COST ESTIMATING METHODS 6.5.1. Historical costs... 

Shortcut calculation methods. In the remainder of this chapter, shortcut calculation methods for the approximate solution of multicomponent distillation are considered. These methods are quite useful to study a large number of cases rapidly to help orient the designer, to determine approximate optimum conditions, or to provide information for a cost estimate. Before discussing these methods, equilibrium relationships and calculation methods of bubble point, dew point, and flash vaporization for multicomponent systems are covered. 

In this context, there are thus new opportunities to use field methods which can present well-known advantages such as the provision of information at lower cost and/or more quickly, the absence of artefacts caused by samples handling, transportation and storage, the possibility of rapid and real time analysis and the estimation of spatial and temporal variability (Buffle and Horvai, 2000). 

This table illustrates one of the major impediments to the rapid assimilation of immunochemical technology into pesticide residue analysis labs. Because of the amount and variety of work involved, new method development costs may be high when compared to routine chromatographic methods. However, the low cost per run allows for rapid recovery of the initial investment with sufficiently high sample loads. For example, the cost of reagents and supplies for an ELISA for diflubenzuron was estimated to be 0.20/sample as compared with 4 for HPLC or 11 for GC (35). In addition to the lower reagent and supply costs, the major economic advantage of immunoassay is the dramatic decrease in labor costs. 

Many of the variants can of course be eliminated at the start for trivial reasons (Table 4-2). However, even the number of potential variants left is still so large that it is impossible to calculate investment and production costs for all of them. Furthermore, at this point the information available for doing this is often inadequate and there is consequently a risk of eliminating promising variants. At this stage one can further reduce the number of remaining variants (max. 3 or 4) by means of methods for the rapid estimation of costs (Section 6.1.6). 

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