Economic evaluation utility operating costs

The high capital investment cost of the Asahi process is due to the necessity for large absorbers, evaporators, crystallizers, dryers, rotary kiln crackers and screw decanter separators. The major operating and maintenance costs are electricity, fuel oil, steam and chemicals such as soda ash, EDTA and limestone. The requirement for consumption of large amounts of utilities is associated with the operation principle and design of the Asahi process. According to the economic evaluation, equipment required for N0X and SO2 absorption (such as packed-bed absorbers) accounts for 20% of total direct capital investment for treatment of dithionate ion (such as evaporator, crystallizer, dryer, and cracker) it accounts for about 40% and for treatment of nitrogen-sulfur compounds (such as screw decanter and cracker) it accounts for only 2%. 

Step 5. Economic evaluation. Not shown in this example, but included in a process synthesis program such as PIP, are algorithms for costing and economic evaluation of the process. Process equipment is sized and priced and total plant investment is estimated. Requirements and costs for utilities and raw materials, other operating costs, and product values are estimated. These values are used to evaluate the profitability of the proposed process and can provide a sound basis for a more detailed design. 

Coextruded films are produced by a tubular-blown film process and a flat-die, chill-roll casting process. Capital and operating costs for blown-film vs cast-film coextrusion lines are strongly dependent on product mix and utilization. Equipment suppliers provide comparative economic evaluations for specific products. Practical cast-film equipment has been discussed previously (3). Coextrusion dies are unique. Extruders used before the die and take-away equipment used afterwards are standard equipment for single-layer film manufacture of blown or cast film (see Extrusion). 

There are a mrmber of options available to refiners to meet the increase in hydrogen demand. Before deciding to proceed with any option, refiners should conduct a comprehensive technical and economic evaluation of their existing operations and evaluate the technical and economic benefits of the options available to them. The option that provides the optimum economic and operations benefits will be different for each situation and will depend on such ftings as the existing steam balance, the cost and availability of utilities, plot limitations, and the condition of existing hydrogen plants. 

These utility costs, together with other economic parameters applicable to the plant being evaluated, can be incorporated into a cash flow model and the overall production costs of hydrogen can be evaluated. The other economic parameters include such things as capital cost, start-up cost, odier operating costs (including catalyst replacement and tube replacement), and maintenance costs. From this model, the internal rate of return (IRR), net present value at various rates of return (NPV), net cash flow, and a generated income statement can also be developed. 

The second reason for environmental projections is the significance of control costs. For example, proposed acid rain legislation could cost utilities and their customers billions of dollars. Before this money is spent, it is important to be able to evaluate the effects that controls may have on emissions, on employment, in different regions of the country, and the like. A large share of S02 emissions are from older, dirtier, coal-fired power plants. If these plants are retiring in a few years, it may not make economic sense to spend millions or billions of dollars to retrofit them with controls. On the other hand, if such plants will be operating for many years to come, the benefits may be considered worth the expense. 

Thus, knowing the prices of 1 kg steam and 1 kWh, the utilities cost can be estimated by using the above information. It is usual to allow an increase to the utilities cost of 20% in order to cover thermal losses and other charges. A more detailed economic analysis is given in Ref. [37], which has economic data, analysis, and evaluations that are based on the various operational policies considered in the research studies presented in Refs. [6,37], which have considered the removal of both frozen and bound water. 

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