Fuel Type Dependence

A first analysis related to the effect of two operating parameters fuel flow and cell operating temperature. The experimental domain chosen in order to carry out the experiments was the following  

Fuel utilization factor range 0.2-0.8 at the current density of 0.5 A/cm,  

Operating temperature (measured at the center of the circular anode electrode) range 650°C-800°C 

The range adopted for the temperature depends on the considered types of cell materials (YSZ electrolyte and LSCF cathode). The range adopted for the j/j depends on realistic values encountered in laboratory experiments and on real stack operation. The analysis was done with consideration given to the crossing effects of the two parameters. 

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The fuels Hsted in Table 2 are generally representative of fuels to be encountered over the range of industrial furnaces and, depending on the type (cooled or refractory wall), exhibit operating temperatures considerably different from adiabatic values. The choice of fuel is dependent upon a number of factors including cost, availabiUty, cleanliness, emissions, reflabiUty, and operations. Small furnaces tend to bum cleaner, easier to use fuels. Large furnaces can more effectively use coal. 

Particulates Combustion-related particulate emissions may consist of one or more of the following types, depending on the fuel. 

There are many types of steam boilers, depending on the steam pressure, steam output and fuel type. Blowdown is required to remove the dissolved solids not removed in the boiler feedwater treatment. The efficiency of the boiler depends on its load. 

Repeat the calculation of the previous problem for the initial condition that the air is at an initial temperature of 1000K. Further, calculate the burning time for the benzene in pure oxygen at 298 K. Repeat all calculations with ethanol as the fuel. Then discuss the dependence of the results obtained on ambient conditions and fuel type. 

Immunoassay tests do not identify specific fuel types and are best used as screening tools. The tests are dependent on soil type and homogeneity. In particular, for clay and other cohesive soils, the tests are limited by a low capacity to extract hydrocarbons from the sample. 

Because the components and design of a fuel processing subsystems depend on the raw fuel type, the discussion after Table 9-1 is organized by the fuel being processed. 

The active layer must provide the required activity, selectivity and thermochemical stability properties. Different active phases can be adopted depending on the operating constraints and the fuel type. In the following we will mainly focus on CH4 (i.e. the main constituent of natural gas) as the reference fuel for GT applications. In this respect, the combustion catalysts that have been most extensively investigated for configurations based on lean combustion concepts are PdO-based systems and metal-substituted hexaaluminates. 

Changing the initial mixture temperature affects stability. U0 for blow-off from burners increases with approximately the square of the absolute temperature, whether the flow is laminar or turbulent (17). The exact dependence on temperature is a function of fuel type and concentration, and may also be affected by wall temperature. The flash-back velocity is even more sensitive to temperature (17), so that raising the temperature may actually decrease the relative range of flow velocities that will permit stable flames on burners. As to supported flames, the correlations in Table IV show that blow-off in such systems is less dependent on initial temperature than is blow-off from burners (38) the exponent on 7 > is only 1.2, as compared with 2.0. 

There are several types of fuel cell depending on the working temperature and type of electrolyte ... 

In enclosure fires, radiation may be the dominant mode of heat transfer. For flames burning in an open atmosphere, the radiative fraction of overall heat transfer ranges from less than 0.1 to 0.4, depending both on the fuel type and the fire diameter [45], Owing to the important role that radiation plays in fires, all fire CFD models have a radiation model that solves the radiation transport equation (RTE) [46,48] ... 

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