Fuel reactor temperatures

As a hard, high melting carbide and possible constituent of UC-fueled reactors, zirconium carbide has been studied extensively. The preparation, behavior, and properties of zirconium and other carbides are reviewed in Reference 132, temperature-correlated engineering property data in Reference 133 (see also Carbides). 

Selectivity to desired products including light hydrocarbons, gasoline, or diesel fuel depends upon the catalyst employed, the reactor temperature, and the type of process employed. Products of the F-T synthesis are suitable for further chemical processing because of their predominantly straight chain structure and the position of the double bond at the end of the chain. By-products formed on a lesser scale include alcohols, ketones, acids, esters, and aromatics. 

Most of the oxygen injected into a gasifier, either as pure oxygen or air, is consumed in reactions (1) through (3) to provide the heat necessary to dry the solid fuel, break up chemical bonds, and raise the reactor temperature to drive gasification reactions (4) through (9). 

A continuous flow stirred reactor operates off the decomposition of gaseous ethylene oxide fuel. If the fuel injection temperature is 300 K, the volume of the reactor is 1500 cm3, and the operating pressure is 20 atm, calculate the maximum rate of heat evolution possible in the reactor. Assume that the ethylene oxide follows homogeneous first-order reaction kinetics and that values of the reaction rate constant k are... 

A fast-start capability is a key requirement for a compact fuel processor, especially crucial for specific cases such as on-board automotive application. A possible means for the fast start-up of an ATR reactor is starting by feeding to the reactor a mixture with an O2 C molar ratio typical of a rich combustion. The goal of this mode is to raise the reactor temperature quickly and simultaneously avoid catalyst oxidation. Then the reactor will move to the ATR mode through the addition of steam and by decreasing the 02 C feed ratio to the desired value. 

The reactor temperature required to prevent coke formation varies considerably for the different processes. Table 2.1 summarizes the values calculated assuming thermodynamic equilibrium for 2,2,4-trimethylpentane reforming. Generally, the coking tendency increases in the following order at constant O/C ratio SR > ATR > POx. These calculations demonstrate that at steam to carbon ratios (S/C) > 2 and reaction temperatures > 600 °C, which is very common for hydrocarbon fuel processors, coke seems to be an unstable species especially under the conditions of steam reforming. 

MeV H, and 0.8 MeV He3 formed by the D-D reactions in advanced fuel reactors. The energy spectrum of the central plasma can be expected to be Maxwellian at the Tokamak operating temperature ( 10 keV). There is little or no information on the interaction between blistering and externally induced stress. Thermal and mechanically induced stress will influence diffusion and this will have a direct effect on blistering. 

Color Degradation of Diesel Fuel in Deep Desulfurization. The color of diesel fuel is degraded in the higher reactor temperature range of deep desulfurization.2) The color bodies (fluorescence compounds) are thought to be polyaromatics which are... 

Table 6 shows an example of the cyclic steady state performance of the SERP concept using an admixture of a SMR catalyst (noble metal on alumina) and a CO2 chemisorbent (K2CO3 promoted hydrotalcite) in the reactor [20]. The reactor temperature was 490°C. The feed H20 CH4 ratio was 6 1. The concept can directly produce 95% H2 product (dry basis) with a CH4 to H2 conversion of 73%. The trace impurities in the product gas contained less than 40 ppm COx- The corresponding product gas composition (thermodynamic limit) of a SMR reactor operated without the CO2 chemisorbent will be -67.2% H2, 15.7% CH4, 15.9% CO2, and 1-2% CO (dry basis), and the CH4 to H2 conversion will be only 52%. Thus, the SERP concept may be attractive for direct production of a CO free H2 stream for fuel cell applications. 

Some coal liquefaction methods, such as the Synthoil (5) process and the CO-steam (6) process, are similar to solvent refining in their approach, but more severe conditions or a catalyst are used to give a fiuid product. In the Synthoil reaction, bituminous coal is pulverized, dispersed in a vehicle oil, and hydrogenated in a packed tubular reactor with or without added catalyst. The CO-steam process uses lignite coal and less expensive synthesis gas. The intended product is a heavy liquid fuel having ash, sulfur, and nitrogen contents suflBciently low to avoid stack-gas cleaning. Reactor temperature and pressure are normally 400°-450°C and 4000 psi, respectively. 

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