Catalyst continued effectiveness

Equilibrium (continued) calculations, 192 constant, 151, table, 154 crystallization and, 144 dynamic nature of, 144, 165 effect of catalyst, 148 effect of concentration, 148 of energy, 167 of randomness, 166 of temperature, 67. 148, 167 factors determining, 155, 158 law of chemical, 152, 173 liquid-gas, 66 qualitative aspects of, 142 quantitative aspects of, 151 recognizing, 143 slate of, 142, 147 sugars, 425 thermal, 56... 

Wan et al. [61] also reported the highly effective conversion of methane to aromatic hydrocarbons over Cu, Ni, Fe, and Al catalysts. The effects of the type of catalyst, its configuration, and the microwave irradiation conditions on reaction path and product selectivity were examined under both batch and continuous-flow conditions. 

PtMo alloys are not as effective as PtRu for methanol, or ethanol, oxidation. As shown in Figure 29, the d band vacancy per Pt atom for the PtMo/C catalyst continues to increase until 0.6 V vs RHE, in contrast to the behavior of PtRu/C. ° The authors attribute this difference to the lack of removal of the Cl fragments from the particle surface by the oxy-hydroxides of Mo. However, the difference in the electrocatalytic activity of PtRu and PtMo catalysts may be attributed to ensemble effects as well as electronic effects. The former are not probed in the white line analysis presented by Mukerjee and co-workers. In the case of methanol oxidation, en-... 

SOx emissions from FCCU s can be reduced by the use of SOx catalysts, especially SOx additives which can be added to the FCCU independently of the cracking catalyst. The effectiveness of these catalysts is favored by lower regenerator temperatures, the presence of combustion promoter, and higher oxygen concentrations. Deactivation of these catalysts occurs by loss of surface area and poisoning by silica. We believe that SOx additives will eventually be used by most refiners to control SOx emissions from FCCU s, either on a spot or continuous basis. 

Continuous analysis of highly fluorinated materials can present problems, primarily caused by the corrosiveness of hydrogen fluoride which is liberated from all of them during combustion. Hydrogen fluoride will react with the permanently bound hydroxy groups on the surface of the cooler parts of combustion tube walls and catalysts. The effect can lead to erratic hydrogen values and so the installation of some type of oxide [magnesium oxide, alumina, or cerium (IV) oxide] trap in the combustion tube to prevent its escape is recommended. 11... 

Alkane dehydroeyelization with Pt-Sn-alumina catalysts—Continued pressure effect, 120 PtSn alloy formation, 117-118 role of Sn, 117 Sn vs. carbon deposition, 120 Sn vs. coking, 118-119 Sn vs. n-octane conversion, 120-122 Sn vs. selectivity, 118 temperature effect, 119 Alkene hydroformylation, asymmetric catalysis, 24... 

Activation energy—Continued effect on reaction rates, 261 hydrogen desorption, 183 use of differences for selectivity control, 260 Active metals content, effect on catalyst activity, 283,285/... 

An analysis is made of the factors which pose a limit to representative downscaling of catalyst testing in continuous fixed-bed reactors operated with either gas or gas-liquid flow. Main limiting factors are the axial dispersion and, in the case of gas-liquid operation, also the contacting of the catalyst. The effects of catalyst and reactor geometries are quantified, and boundaries for safe operation are indicated. 

Catalyst systems are complex in themselves, requiring complex control technology and skilled use of expensive equipment to ensure their continued effectiveness, care in fuel and vehicle use, and regular skilled maintenance, which may be beyond the capability of the third and fourth owners. 

Minimum catalyst fouling effects due to the possible continuous removal and catalyst replacement... 

---