Open-cycle economics

In open cycle, the diesel has the higher efficiency, making it more attractive for light fuel oils. However, in combined cycle, the gas turbine often has the highest overall efficiency, but there is the penalty associated with the additional cost for boiler and turbine. Nevertheless, unless the prime fuel is of low cost, the use of combined-cycle gas turbine plant will prove to be the more economic. 

The low consumption of chemicals and energy indicate an economic advantage over similar open cycle processes. 

Similar "open-cycle" scoping studies using waste SO2 from combustion flue gases and SO2 produced from sulfur show equivalent economic potential. The latter, of course, would have a higher sulfuric acid production cost because the sulfur feedstock would have an acquisition cost that must be included in the economics. Nevertheless, the cost of sulfuric acid, when tempered by the revenue obtained from the sale of hydrogen, can be extremely attractive. The reverse is also true. 

More efficient coal utilization can be realized with combined power plant cycles. For instance, the post combustion gases of a conventional combustor or an advanced MHD system can be further utilized to drive a gas or steam turbine. However, the sustained durability of downstream turbine or heat exchanger components requires minimal transport of corrosive fuel impurities. Control of mineral-derived impurities is also required for environmental protection. For the special case of open cycle-coal fired MHD systems, the thermodynamic activity of potassium is much higher in the seeded combustion gas (plasma) than in common coal minerals and slags. This results in the loss of plasma seed by slag absorption and is of critical concern to the economic feasibility of MHD. 

The minimum production and cumulative need values naturally refer to an extensive use of fast reactors the maximum values to the use of open-cycle LWR reactors alone. These data, related to the economically exploitable uranium resources, show that no problems of uranium supply should exist before the year 2000 thereafter the choice of an adequate strategy (including, if possible, a non-marginal use of FBR) becomes fundamental in providing a satisfactory answer to the problems of fuel supply. 

The business climate of the 1990s is different from the past. Factors such as increased competition, a global marketplace, rapid technical shifts, and greatly compressed product life cycles constantly open new opportunities for plastics in general and reinforced plastics in particular. Reinforced plastics have become widely accepted for particular appHcations because they offer a combination of design, performance, and economic benefits to the user. These materials have had a proven record of success since the 1940s. 

In terms of cost, the effectiveness of the catalytic cycle in the ring closure makes this process economical in palladium. The first three steps in the reaction sequence -- ring opening of an epoxide by a Grignard reagent, converison of an alcohol to an amine with inversion, and sulfonamide formation from the amine — are all standard synthetic processes. 

At the end of the regeneration step, the CO2 flow is stopped, the vessel is opened to allow the CO2 to depressurize, and the activated carbon is removed via slurry pumps. The vessel is then refilled with spent activated carbon, the water drained, and the desorption process repeated. Incidentally, the CO2 left in the vessel at the end of the regeneration cycle is lost in this procedure. Although the cost of CO2 is rather low, about 5-10 cents per pound depending upon the volume used, its consumption should be considered in evaluating the viability of a process, especially if the cost of the material being extracted is low. The CO2 that is lost represents an economic penalty for this process, but part or all of it can be recovered with the installation of an additional CO2 surge tank system. 

Economic — Low costs for machine and molds — Short cycle times — More economical for mass products and large-scale parts — More investment in research and technology necessary to increase process repeatability and to open the market for new applications... 

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