Non-operating costs

Dispersible silicone emulsions are generally preferred for aqueous systems, whereas silicone fluids and compounds are preferred for non-aqueous systems. Silicones are widely employed in cooling water treatment programs, less so in boiler plants because of higher operating costs than available alternatives, but also because of sometimes questionable emulsion stability at higher temperatures. 

The present state of the art in blood pH measurements allows for rapid (1 minute) determination of pH between 6.4 and 8.0 to within at least 0.005 units for whole blood sample volumes < 100 microliters. The temperature of the electrodes and sample is generally controlled to within 0.1 °C for this level of precision and frequent calibration is carried out (in some cases a one point calibration for each sample). The electrodes require (both the glass and external reference) some maintenance due to protein fouling, however this procedure is largely automated. The useful life of an electrode is one year or less and the cost is well over 100 (U.S.) each. New technologies, both electrochemical and non-electrochemical, must compete with this attractive performance and provide for lower operating costs in order to be successful. 

Sciubba (2003) proposed an approach called the extended exergy accounting (EEA), which calculates the real, resource-based value of a commodity product. The time span of EEA is the whole life of a plant. The EEA includes the exergetics flow sheets for non-energetic costs of labor and environmental remediation expenditures, and hence uses extended exergetic content. It also defines the criterion for an optimum process or operation (Sciubba, 2003). 

Whether produced from fossil or non-fossil sources, the widespread use of hydrogen will require a new and extensive infrastructure to produce, distribute, store and dispense it as a vehicular fuel or for stationary applications, such as electric generation. Depending on the source from which hydrogen is produced and the form in which it is delivered, many alternative infrastructures can be envisioned. Tradeoffs in scale economies between process and distribution technologies, and such issues as operating cost, safety, and materials can also favour alternative forms of infrastructure. 

The aMDEA solvents are non-corrosive due to their chemical structure. This allows a high sour gas loading and therefore reduced solvent circulation rates, which results in low investment and low operating costs. 

The attractiveness of surface/pore characterization via NMR spin-lattice relaxation measurements of pore fluid lies in the potential advantages this technique has as compared to the conventional approaches. These include rapid analysis, lower operating costs, analysis of wet materials, no pore shape assumption, a wide range of pore sizes can be evaluated (0.5 nm to >1 /im), no network/percolation effects and the technique is non-destructive. When determining specific surface areas, NMR analysis does not require out-gassing and has the potential for on-line analysis of slurries. 

The typical US well head cost in 2007 was around 6.37/GJ and this has been used as the basis for the input cost in this case study. The fixed costs are the non feed operating costs which for a relatively simple turbo-expander gas plant would be about 5% per annum of the fixed capital and the capital recovery charge which is placed at 14.3% per annum of the capital (see Appendix for derivation of this value). 

The capital cost of a 500,000 t/y ethane cracker is 718 million (2007). The non-feedstock operating costs are taken as 10% of the capital per annum or 71.8 million per year (MM /y). If the plant is built in three years on the basis of a 20 year life with a DCF rate of 10%, annual return on capital, as detailed in the Appendix, is 14.4% or 102.8MM/y. 

The largest cost item of the open system is the feedstock cost, followed closely by the capital and fuel costs at nearly 20% each. Non feed and fuel operating costs are about 14% of the total unit production costs. 

For the CLOSED system, after feedstock costs, capital charges are the largest item followed closely by non-feed operating costs. Fuel cost is very much reduced as the unsold by-products are used to displace the fuel import into the plant. Fuel cost is only about 6% of the total. Non feedstock operating costs and fuel costs are about 22% of the total unit costs. 

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