Economic evaluation steam costs

An economic evaluation will ascertain the cost for power generation when compared with purchase of electricity and (where applicable) generation of steam in low-pressure boilers. This evaluation will consider the following ... 

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%. 

A Techno Economic Evaluation revealed the main factors influencing the costs and thereby the cost-effectiveness of a membrane steam-reformer compared to conventional processes (chapter 2). The evaluation showed that membrane steam reforming can be cost-effective. 

As shown in Figure 12, economic evaluations for an n -of-a-kind Si-Based H2-MHR show the hydrogen-production costs are competitive with those for steam-methane reforming [10]. Economic evaluations for the HTE-based H2-MHR are currently being evaluated and will depend significantly on the unit costs for the SOE modules. Preliminary evaluations show the hydrogen-production costs for both plants to be comparable if the SOE module unit costs are approximately 500 per kW(e). 

The application of membrane reactors to methane reforming has also been evaluated in two recent studies. A technical and economic evaluation of the use of dense Pd-membrane in methane steam reforming has been presented by Aasberg-Petersen et aL [6.10]. They assumed a thin (2 Lim thick) Pd membrane, which exhibited perfect separation and, as a result, the pure hydrogen product was taken from the permeate side of the membrane. No sweep gas was used on the permeate side of the reactor. This necessitated compression of the low pressure hydrogen product. The authors concluded that membrane-based reforming using a dense film membrane became attractive only in the cases where electrical costs were low. 

If utilities are generated inside the facility, such as cooling water, the capital cost for outside the battery limits facilities are evaluated by APEA. Using the specified indirect cost, discount rate, tax, and interest, the discounted cash flow and the economic indicators are generated by APEA with the method described in Section Economic Sustainability Analysis. Parameters for economic evaluations and prices of the raw materials and products are shown in Table 6.8. Utility costs for electricity, steam, and... 

The most economically effective area of SVBR-75 use could be the renovation of NPP units with thermal reactors after the expiration of their lifetime. Such renovation could be performed by installing the SVBR-75/100 modules in the steam-generator (SG) and the main circulation pump (MCP) compartments of these NPPs after the decommissioning and dismantling of the equipment installed previously. The results of technical feasibility study and economic evaluation of the renovation of the 2" , 3, and d " units of the Novovoronezhskaya NPP with the SVBR-75 reactor modules show that the specific capital costs can be reduced by a factor of two compared with the construction of new replacement power capacities [XIX-5] ... 

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. 

As shown in Fig. 2.24.2, in large plants the absorption system is more economical than compressor installations, independently of the price of steam or electricity. The low maintenance cost are reflected in the calculation, but the high uptime and reduced production interruption should also be accounted for in an evaluation no large, heavy moving machine parts are the reason for this advantage. 

The economic analysis to follow depends upon the evaluation of the various available-energy supplies for feedwater heating and, in turn, the costs associated with those supplies. In particular, the costs of interest, for each case, are those required to take the feedwater from the conditions at the inlet to heater number 4 to the normal temperature of feedwater entering the boiler. These costs include the cost of bleeder steam, which is used to increase the temperature of feedwater in the heater and, under the conditions of Case C, the cost of the additional boiler fuel required when the heater is out of service and the temperature of the feedwater is below normal. The hourly cost of feedwater heating for Cases A and B is given by... 

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. 

The economics of the four basic compound fertilizer production processes (bulk blending, compaction granulation, steam/water granulation, and chemical granulation) are compared in terms of (1) required fixed captal investment, (2) conversion cost (not including raw materials), and (3) production cost (conversion cost plus raw material cost). The premises and assumptions used in this evaluation and a discussion of the main economic characteristics of the processes follow. 

The variability in energy savings and capital costs still depends on the existing evaporator conditions. For existing multi-effect units in which the total amount of first-effect vapor is now used in the second effect, the choice and location of the steam-jet thermocompressor are more complicated because the heat balances and heat-transfer rates are affected for each evaporator reaction. The economics may still be favorable to justify the technical evaluation and modification. Since the limitations of steam-jet thermocompressors are a compression ratio below 1.8 and new heat-transfer rates, the first effect normally becomes the best location. 

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