Partial oxidation three-zone

The partial oxidation reactor is broken into three distinct reaction zones. Initially, the fuel oil is injected into the reactor along with oxygen and steam. The heating vaporizes and cracks the hydrocarbon material. The steam is used to control the temperature of the reactor. The hydrocarbons, oxygen, and steam are well mixed at this stage. 

Additive and impurity rejection at the growing crystal front leads to uneven distribution in a crystalline polymer. This redistribution process has been studied by UV and fluorescence microscopy and by an electron microscope with energy dispersive x-ray analysis. In polymer samples which are quenched after rapid crystallization, the additive distribution is kinetically determined and may be modeled in a computer as a three-dimensional zone-refining process. In annealed polymer samples, low molecular weight additives are uniformly concentrated in the amorphous phase. The additive distribution reflects that of crystalline material within the polymer. Antioxidant and uv stabilzer redistribution probably does not have a major effect on polymer stability, but the redistribution of partially oxidized, impure polymer may be important... 

The electrolyte in an SOFC must consist of a good ion conductor, which has essentially no electronic conductivity. Otherwise the cell will be internally short-circuited. An often-used electrolyte material is yttria-stabilised zirconia (YSZ). The electrodes must pos.scss good electron conductivity in order to facilitate the electrochemical reaction and to collect the current from the cell. The fuel electrode usually contains metallic nickel for this purpose. The anodic oxidation of the fuel (H or CO) can only take place in the vicinity of the so-called three-phase boundary (TPB), where all reactants (oxide ions, gas molecules and electrons) are present. Thus, it is advantageous to extend the length and width of the TPB zone as much as possible. One way to do this is by making a composite of Ni and YSZ called a Ni-YSZ-cermet. Another way is to use a mixed ionic and electronic conductor, which in principle can support the electrochemical reaction all over the surface as illustrated in Fig. 15.1. Partially reduced ceria is a mixed ionic and electronic... 

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