Fuel Processing Calculations

The necessary fuel processing of natural gas or other hydrocarbons and coal before its use in the SOFC changes the system design. The following investigations have been done for methane as the main component of natural gas to keep the calculations simple. A common type of fuel processing for hydrocarbons is the endothermic steam reforming process as shown for methane in Equation (2.105) with the heat demand Equation (2.106)... 

Abstract In this paper, we discuss the results of a preliminary systematic process simulation study the effect of operating parameters on the product distribution and conversion efficiency of hydrocarbon fuels in a reforming reactor. The ASPEN One HYSYS-2004 simulation software has been utilized for the simulations and calculations of the fuel-processing reactions. It is desired to produce hydrogen rich reformed gas with as low as possible carbon monoxide (CO) formation, which requires different combinations of reformer, steam to carbon and oxygen to carbon ratios. Fuel properties only slightly affect the general trends. 

Fuel processing (r Fp), PEM fuel cell (r Fc), and overall system efficiencies (rjnet ei) are calculated as follows ... 

Skrifvars, B-J., Backman, R., and Hupa., M., Characterization of the sintering tendency of ten biomass ashes in FBC conditions by a laboratory test and by phase equilibrium calculations . Fuel Processing Technology 56(1998)55-67. 

Plasma-Stimulated Partial Oxidation of Liquid Fuel into Syngas (CO- H2). Explain why the total energy efficiency of syngas production by partial oxidation of liquid fuels is always less than 100%, even in the ideal plasma process (for example, the efficiency is 65% for diesel fuel conversion see Section 10.2.4). A fraction of energy is always converted into heat in the processes. Calculate the maximum energy efficiency for conversion of kerosene... 

The standard chemical exergy of a substance not present in the environment can be calculated by considering a reversible reaction of the substance with other substances for which the standard chemical exergies are known. For energy-conversion processes, calculation of the exergy of fossil fuels is particularly important. 

Utilities include electricity, steam, process fuel, process water, boiler feedwater, cooDng water, deionized water, compressed air, instrument air, refrigeration, inert gas, and effluent treatment. The unit use is dependent on die process technology, and the cost is site dependent. For each utility, unit use and unit cost should be recorded. The estimated use of utilities for different fertiDzer processes is shown in Table 21.6. Some offsite utilities such as electricity are often priced with a fixed cost component and a variable cost component. The fixed and variable portions need to be calculated separately to provide an average variable cost per unit of production for a given annual production. 

The results from these experiments show the applicability of this method for monitoring the subcriticaiity of fuel solution tanks in fuel processing or reprocessing facilities. This paper describes, calculations of these spectral densities and the spectral density ratio as a function of frequency using the JPRKINETICS code and compares the calculated with measured results. 

Panasonic, with Tokyo Gas, announced in January 2013 that it had reduced the price (excluding installation) of its domestic PEM fuel cell system to 1,995,000 by approximately 760,000, a reduction of 27.5 % from its 2011 model. This itself was a reduction from its 2009 model (selhng at 3,465,000 [104]) of 20 %. A year or so earlier in January 2012 Toshiba, with Osaka Gas, announced that it had reduced the price of its domestic fuel cell system by 650,000- 2,604,000, a 25 % reduction in cost [105]. In both cases sales increases were anticipated and further cost reductions expected. The Panasonic announcement also included further information on the performance and other aspects of the unit. The cost reduction was associated with an improvement of lifetime from 50,000 to 60,000 h a reduction in components by 20 % reduced weight by 10 % and reduced size overall. Of significance was a reduction in noble metals in the fuel processing subsystem by 50 % and platinum catalyst by 50 %. Total efficiency, both heat and power, was calculated at 95 % LHV. 

To assess core neutronic performance, the equilibrium cycle performance was calculated with a cycle length of 330 days and the Keff of 1.002 at EOC. In bum-up calculations, actinides heavier than and lighter than Th were ignored. For external fuel cycle calculations, all actinides in the chain were assumed to be extracted by pyro-processing and repeatedly recycled in the reactor. 

If a concentration of 1 pCi persists for 40 years (the operating life of a hypothetical fuel processing plant), an accumulation of 1.3 x 10 pCi m could deposit on the soil surface. If uniformly mixed in a plow layer 20 cm deep, the resultant concentration in soil (of density 1.5 g cm ) would be 4.2 x 10 pCi I kg" although removal in runoff or percolation could reduce this value. Plants growing in this soil would absorb the radionuclide via root uptake and reach concentrations of 840 pCi I kg . This value is 30% of the concentration calculated above for fresh forage (2900 pCi kg ), and 150% of the concentration calculated for cereal from direct deposition alone (Book etai, 1977). 

Dose estimates from other measured environmental samples are many orders of magnitude loiver than the estimates calculated in the previous sections for a concentration of 1 pCi m in air. The peak concentration of 2 pCi L as determined in milk samples near the Nuclear Fuel Services plant, would require maintenance of an air concentration of 1.7 X 10 pCi m , according to the model used above. Concentrations of in air around nuclear power plants are so much lower than those calculated for air around fuel processing facilities that they are essentially undetectable. 

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