Overall costs

For more complex examples, total cost profiles return step changes such as shown in Fig. 7.12 (due to changes in Nu ts and /Vshklls)-These step changes are easily located, prior to design, through simple software. Most important, extensive experience has shown that predicted overall costs are typically accurate within 5 percent or better. ... 

Figure 8.1 Overall cost tradeoffs as functions of reactor conversion.

Figure 8.3 Overall cost tradeoffs decomposed according to the onion model.

A great deal of tax money is spent in support of fundamental research, and this is often defended as having an intrinsic virtue. To take the present topic as an example, however, the study of just how molecules adsorb and react on a surface is fascinating and challenging, yet the tax-paying public should not be asked merely to support the esoteric pleasures of a privileged few. The public should expect the occasional major practical advance whose benefits more than pay for the overall cost of all research. The benefits in the present case come from the discovery and development of catalytic processes of major importance to an industrial society. 

World reserves of germanium have been estimated at 4000 metric tons, but it is impossible to discuss reserves without considering price. In many apphcations, the cost of germanium is but a small part of the overall cost of the product. Thus substantially higher germanium prices would have Htde impact on such uses but would expand germanium reserves significantly. 

A researcher planning a strategy must determine if a commitment to appHcations research is required. If so, the cost of faciHties and personnel and the time required to assemble these must be calculated and included in the overall cost of entry. 

A researcher planning strategy must determine whether commitment to a technical service faciHty and personnel is required. If it is, the cost of this commitment must be deterrnined and included in the overall cost of entering the product field. 

Nonformaldehyde Finishing. The concern for formaldehyde release prompted interest in the development of cross-linking systems that did not contain formaldehyde. A number of systems were investigated but generally these systems seemed to fall short in performance (106,107). For example, l,3-dimethyl-4,5-dihydroxyethyleneurea (DMeDHEU) (5) has been used in Japan since 1974. This same agent has been marketed in the United States and elsewhere, but generally the level of smooth-dry performance is substantially lower than the level achievable with DMDHEU. The cost of dimethylurea also raises the overall cost of DMeDHEU above that of DMDHEU. 

Energy costs ate not direcdy related to the energy efficiency of the process (6,42). Even if the thermal efficiency of a steam ejector, for example, is less than that of mechanical equipment mn by an electdc motor, the overall cost of the energy to mn the steam ejector may still be less. 

Syrup Mixing and Handling. Most parent companies sell concentrated flavor bases to franchise bottlers and allow the bottlers to mix this with their own sweetener and water. This defrays shipping costs and reduces the labor demand on parent company manufacturing. In return, franchise bothers are able to purchase sweeteners from local suppHers at a substantial discount and reduce their overall costs. 

A popular overall factor refinement, known as the Hand factor approach, uses a different factor to estimate overall costs for each class of equipment to cover all labor field materials, eg, piping, insulation, electrical, foundations, stmctures, and finishes and indirect costs, but not contingencies. Hand factors range from 4 for fractionating towers down to 2.5 for miscellaneous equipment. 

Actual Costs versus Standard Costs Let us consider the sales, profits, and manufacduring-cost data in Table 9-40. The gross profit is 33,129 per period better than e)mected. Clearly, there is less incentive to investigate overall costs when the profit variance is favorable than if the profit were less than expected. However, standard costing enables an objective analysis of the data, whether good or bad, to be made. 

Recovery of the solvent, sometimes by chemical means but more often by distillation, is almost always required, and the recoveiy system ordinarily is considered an integral part of the absorption-system process design. A more efficient solvent-stripping operation normally will result in a less costly absorber because of a smaller concentration of residual dissolved solute in the regenerated solvent however, this may increase the overall cost of solvent recoveiy. A more detailed discussion of these and other economic considerations is presented later in this section. 

Selection of Equipment If a new product is being considered, the preliminaiy study must be highly detailed. Laboratory or pilot-plant work must be done to establish the controhing factors. The problem is then to select and instaU equipment which 1 operate for quantity production at minimum overall cost. Most equipment vendors have pilot equipment available on a rental basis or can conduct test runs in their own customer-demonstration facilities. 

Two main benefits accrue from a systems approach to materials handling and packaging. First, a trade-off of investment and operating costs is made possible nigher costs in some parts of a system become permissible in return for much lower costs in other parts. The net result is usually the lowest overall cost. If this is not the case, the reasons for incurring the higher costs can be identified and justified. The second benefit is that customers are not offended by ill-conceived packages, delivery vehicles, or product characteristics. 

Capital Costs A typical medium-scale RO seawater plant might produce 0.25 mVs (6 MGD). For a plant with an open sea intake, seawater salinity of 38 g/1, and conversion of 45 percent, the overall cost woiild be 26.5 miUiou (1996). A capital breakdown is given in Table 22-18. Capital charges are site specific, and are sensitive to the salinity of the feed. A plant of this size would likely contain six trains. For seawater RO, the Best estimate for the slopes of the family of lines in Fig. 22-55 is —0.6 for the equipment and 0.95 for the membranes. Capital charges, shown in TaBle 22-19, usually dominate the overall economics the numbers presented are only an example. Seawater economics are based on Shields and Moch, Am. Desalination Assn. Conf. Monterey CA (1996). 

Manual Component Separation The manual separation of solid-waste components can be accomplished at the source where solid wastes are generated, at a transfer station, at a centralized processing station, or at the disposal site. Manual sorting at the source of generation is the most positive way to achieve the recoveiy and reuse of materials. The number and types of components salvaged or sorted (e.g., cardboard and high-quality paper, metals, and wood) depend on the location, the opportunities for recycling, and the resale market. There has been an evolution in the solid waste indus-tiy to combine manual and automatic separation techniques to reduce overall costs and produce a cleaner product, especially for recyclable materials. 

Once the options have been clearly defined it will be necessary to carry out a cost-benefit analysis of each option. This has two main objectives. First, the overall cost of the project will need to be assessed to determine whether or not it is financially viable and, second, to ensure that those who will be required to incur expenditure are fully aware of the commitment needed. The financial benefits to users of the waters for recreation, fisheries, navigation, etc., are relatively easy to determine, but monetary valuation of the environmental benefits such as conservation and general amenity will be more difficult to define. As yet this aspect of the cost-benefit analysis has not been fully developed in the UK. Having determined a range of options and costs for eutrophication control in a particular catchment, consultation on the details of the Action plan with all those involved is needed before any plan can be implemented. 

Direct-flame afterburners are nearly 100% efficient when properly operated. They can be installed for approximately 350-700 per cubic meter of gas flow. Operating and maintenance costs are essentially those of the auxiliary gas fuel. On larger installations, the overall cost of the afterburner operation may be considerably reduced by using heat recovery equipment as shown in Fig. 29-16. In many industrial situations, boilers or kilns are used as entirely satisfactory afterburners for gases generated in other areas or processes. 

The overall costs for a VFO unit can be lower than the costs of conventional liquid fuel treatment plants. The U.S. Department of Energy conducted a survey that showed that the costs of operating a liquid fuel treatment system over a 20-year period is approximately 0.50 MMBtu... 

In commercially practical terms it may be that although synergism occurs, one additive may be sufficiently less expensive for more to be used to achieve the required stability and still give the lowest overall cost. 

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