Cost correlations process costs

SPC on manufactured products SQC on laboratory operations communicate with corporate CIM system improved QA/QC on products reduced testing costs correlate laboratory analyses and process measurements faster solutions to production problems tested in laboratory faster notification of backlog problems improved electronic data interchange capabiUties automated communication with inventory, ordering, and materials planning systems... 

Equipment Costs. Equipment costs include the purchased cost of process and materials handling equipment, storage faciUties, waste treatment equipment, stmctures, and site service faciUties. Installation costs such as insulation, piping, painting and finishing, foundations, process stmctures, instmmentation, and electrical service connections are estimated or factored separately. Actual quoted prices from suppHers are the best data, but these are not usually available when estimates are made. The quick, inexpensive cost estimates are based largely on personal cost files, internal company cost data, or pubUshed cost correlations. 

Figure 26.53 presents a superstructure for the design of an effluent treatment system involving three effluent streams and three treatment processes17. The superstructure allows for all possibilities. Any stream can go to any effluent process and potential bypassing options have been included. Also, the connections toward the bottom of the superstructure allow for the sequence of the treatment processes to be changed. To optimize such a superstructure requires a mathematical model to be developed for the various material balances for the system and costing correlations included. Such a model then allows... 

Charts, correlations, and tables in the sources cited earlier relate capital costs to various parameters characteristic of the equipment to be evaluated. Table B.2 lists typical parameters used to correlate equipment costs for common types of process equipment. Figure B.3 is an example of such correlations for the cost of heat exchangers as a function of exchanger area. These forms of cost curves generally appear as nearly straight lines on log-log plots, indicating a power-law relationship between capital cost and capacity, with exponents typically ranging from 0.5 to 0.8. 

Cost Estimates - Plant investment costs were developed using cost correlations based on actual plants constructed by Standard Oil Company of California. The important bases for these estimates are summarized in Table XVIII. Costs for the overall Case 1 refinery are broken down and detailed in Table XIX. Investments are categorized as "onplot," those directly concerned with the individual refinery process plants, and "offplot," for auxiliary or supporting facilities, such as utility plants, tankage, etc. The estimating allowances shown... 

The synthesis starts with a single specified feed and a list of acceptable process output streams. It also starts with a list of possible unit transformations. The units are defined by conditions which must be met by the input streams and limitations which describe the outputs in terms of inputs. No more than two input or two output streams are allowed for a unit. A crude cost correlation is also required for each unit. 

Table 2.9 contains the cost of process furnaces, also called process heaters. The cost of a fimiace with a heating rate of20,000 kJ/s is 750,000 in mid 1982. Converting the heating rate, 5.5x10 Btu/h, given in Table 2.4.1, to kJ/s we obtain 1.612x10 kJ/s. This heating rate is below the lower limit of the correlation range given in Table 2.9. Because we have no other data, use the data in Table 2.9 to estimate the heater cost. From Equation 2.15.1 in Table 2.15, we find that the base cost,...

An alternative approach is Bridgewater s method, which correlates plant cost against number of processing steps (Bridgewater and Mumford, 1979). For plants primarily processing liquids and solids ... 

From Table 6.2, the cost correlation for the Axens process for benzene saturation gives C = 0.0061(5)° ... 

Correlations for Estimating Base Equipment Costs for Process Vessels. Referenced to Mid-1968 Dollars with (M S = 273.1). Correlated Using Guthrie s Figures (Low Pressure, Carbon Steel Basis)... 

The fixed capital investment is the cost to build the manufacturing facility. Corresponding to the different levels in the gating process given in Table 16.1 are methods of cost estimation that have different levels of accuracy. Here we describe estimation methods for the conceptual design stages that use process cost correlations (which are usually accurate to 40 to 50%) and the bare module factor method ( 30%). Some estimation methods provide improved accuracy but require vendor quotations detailed estimates of material costs of piping, valves, and insulation and estimates of installation labor hours and the mix of labor rates. Such methods are beyond the scope of this chapter. 

For preliminary evaluation (Gate 1 in Table 16.1), correlations for complete processes scaled up for capacity and for time are commonly used. For a conceptual design (Gate 2), FOB equipment cost correlations based on flow rate are often used and scaled up to BM cost based on L -f M factors. For a preliminary engineering design (Gate 3), the equipment is sized more accurately based on simple rules of thumb, the cost is estimated from FOB cost correlations related to equipment size and scaled up to BM cost based on L + M factors. The process and FOB cost correlations are all of the form... 

For this method, the size, materials of construction, and conditions of operation for the process equipment must be known. The calculation is the same as that used in Example 16.3. The difference is an increase in accuracy for the estimate of the FOB cost because the correlation requires an estimation of size of the unit instead of the flow to the unit. For example, for a bag hlter, we could use a cost correlation based on feed gas flow rate to the filter or, for increased accuracy in engineering design, use a correlation based on the bag hltration area. Since the gas flow rate/unit filter area depends on the specific application, the cost correlation based on filtration area is site specific and therefore more accurate. Cost correlations based on flow rate are usually less accurate ( 25 to 40%) than those based on design size ( 15 to 30%). Rules of thumb, given in Section 16.11, can be used to obtain the size. 

Interest in shale oil is motivated largely by the enormous size of oil shale deposits in the United States. A further reason for interest in oil shale processing is that processes for the production of liquid fuels from oil shale appear cheaper than those that start from coal (2). This is primarily because oil shale contains a very much higfier ratio of hydrogen to carbon, and process costs tend to correlate directly with the increase in the net H/C ratio required. This cost advantage is somewhat offset by increased materials handling required by shale. But, on balance, it is expected that most liquid synfuels will be produced from shale (3). 

Costs should be included with any rules of thumb because costs are such vital information to engineering practice. Therefore, in this book, cost correlations for the FOB cost and factors for estimation of the complete installation of that equipment into a working process are given for each type of equipment. The cost estimates are ball park ideas + 30 %. Here we discuss the correlations, the L+M factors to convert FOB costs into bare module costs, factors to obtain the fixed capital investment costs and finally the capital cost guidelines for the equipment described in the main text, with title captions that are the same as in the main text. 

Finally, some equipment is unaffected by pressure. Exaiiples are tower trays and packing. This equipment is not subjected to significant differential pressure because it is surrounded by process fluid. Therefore, in Equation A.3. use 0 = 2= C3 = 0. Some other equipment also has zero for these constants. For exarrple, conpressor drives are not exposed to the process fluid and so are not significantly affected by operating pressure. Other equipment, such as conpressors, do not have pressure corrections because such data were not available. Use of these cost correlations for equipment outside the pressure range shown in Table A.2 should be done with extreme caution. 

In this example, use of Correlation Master would save 99% of the measurement costs, 99% of the SPC analysis costs and 99% of the process capability analysis costs. Further, the costs of destructive measurement can be eliminated in many... 

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