Process evaluation operating costs

Operating costs can be estimated based on statistical analysis of operating costs in existing plants. Costs of waste disposal can be evaluated in the same way as costs for any chemical process since procedures for disposal include, in fact, unit chemical processes and operations. Costs of utilities and maintenance are best assessed based on the company data banks. Typical utility figures per m capacity of reactors in MPPs are 800-1100 kg steam/h, 60-80 kW power, and 7,000-8,000 kJ/h refrigeration capacity. 

Ideally, the equipment chosen should be that of the lowest total cost which meets all process requirements. The total cost includes depreciation on investment, operating cost such as power, and maintenance costs. Rarely is any more than a superficial evaluation based on this... 

When considering the possibility of using internal combustion drivers, evaluate process requirements and costs. If a low-cost, gaseous fuel is available, gas engines and gas turbines may surpass other drivers in economical installation and operation. In the initial process design stage, a method of establishing the cost of purchase, installation, and operation for drivers is needed. 

Economic evaluations of waste-reduction options should involve a comparison of operating costs to illustrate where cost savings would accrue. For example, a waste-reduction measure that reduces the amount of raw material lost down the drain during the process will reduce raw-material costs. Raw-material substitution or process changes may reduce the amount of solid waste that must be transported offsite, reducing the transport costs for waste disposal. 

This value corresponds to a corresponding y-scale composition of 0.0012, which is less than the supply mass fmction of phenol in either waste stream as well as the pinch composition. Hence, it is thermodynamically feasible for Sf to recover phenol from R] and R2. In addition, miy amount of phenol removed by S5 does not overlap with the load handled by the process MSAs. Therefore, the operating cost of air needed to remove 1 kg of phenol can be evaluated as follows ... 

For small projects, and for simple choices between alternative processing schemes and equipment, the decisions can usually be made by comparing the capital and operating costs. More sophisticated evaluation techniques and economic criteria are needed when decisions have to be made between large, complex projects, particularly when the projects differ widely in scope, time scale and type of product. Some of the more commonly used techniques of economic evaluation and the criteria used to judge economic performance are outlined in this section. For a full discussion of the subject one of the many specialist texts that have been published should be consulted Brennan (1998), Chauvel et al. (2003) and Vale-Riestra (1983). The booklet published by the Institution of Chemical Engineers, Allen (1991), is particularly recommended to students. 

There are different ways of producing chlorine from brine, for example, Dow cells, Hooker cells, and mercury cells. Which process is to be used must be known in order to make an accurate economic evaluation, since the capital costs and operating costs are different for each of these processes. The process engineer may have to investigate the different processes and economically evaluate each before deciding which process is best. 

The overall cost of any process is made up of the fixed investment costs and operating costs. An engineering project is evaluated by balancing these. 

In carrying out an economic evaluation of a proposed process or a modification of an existing one, estimation of future operating costs is just as important as estimating the capital costs involved in the analysis. 

The catalytic esterification of ethanol and acetic acid to ethyl acetate and water has been taken as a representative example to emphasize the potential advantages of the application of membrane technology compared with conventional distillation [48], see Fig. 13.6. From the McCabe-Thiele diagram for the separation of ethanol-water mixtures it follows that pervaporation can reach high water selectivities at the azeotropic point in contrast to the distillation process. Considering the economic evaluation of membrane-assisted esterifications compared with the conventional distillation technique, a decrease of 75% in energy input and 50% lower investment and operation costs can be calculated. The characteristics of the membrane and the module design mainly determine the investment costs of membrane processes, whereas the operational costs are influenced by the hfetime of the membranes. 

In each of the previously mentioned methods lies the possibility for improving the greenness and efficiency of existing and developing processes. This can lead to the reduction and elimination of hazardous solvents, improved process yields, and lower operation costs. However, it is important to note that each method requires a significant amount of data in order to evaluate a pharmaceutical process and appropriate process alternatives. To date, there is not an all-inclusive method that accounts for every possible environmental, human safety, and economic factor of interest. 

The parties agree to establish a committee [or some more convenient operational process] comprising officials and pharmacoeconomic experts nominated by the respective Ministers, to develop and enhance for the purpose of improving public health in their respective nations, the process of scientific cost-effectiveness evaluation and objectively demonstrated therapeutic significance of pharmaceuticals. 

The most significant aspect of the book, however, is the detailed cost analysis and comparison. Each technology is evaluated in a summary table outlining-1) vendor and address. 2) waste characteristics, 3) system capacity. 4) labor and supervision requirements. 5) operating costs. 6) capital costs, 7) revenues generated, and 8) total cosis of operation on an annualized and a per unit basis. This information enables potential users to make explicit, detailed comparative assessments and to build their own financial models. The text points out areas of process or linancial uncertainty, where more research and testing are required, and new applications to be considered. 

Once the toxicant(s) is characterized or identified, the TTE will require the selection of technologies that will remove the specific toxicant(s) or class of substances. The treatment technologies identified may be commercially available, or experimental. However, experimental technologies may be more risky in implementation. The treatment options should be developed and evaluated first at the bench-scale, to assess and verify process constraints, efficiency, operating costs, robustness of the technology to process upsets, and to develop information for engineering scale-up and capital cost. Once this information has been evaluated, decisions can be made to pilot the technologies that have been most successful (Novak et ah, 2002). 

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