Temperature catalyst inlet

Operational Considerations. The performance of catalytic incinerators (28) is affected by catalyst inlet temperature, space velocity, superficial gas velocity (at the catalyst inlet), bed geometry, species present and concentration, mixture composition, and waste contaminants. Catalyst inlet temperatures strongly affect destmction efficiency. Mixture compositions, air-to-gas (fuel) ratio, space velocity, and inlet concentration all show marginal or statistically insignificant effects (30). 

Figure 11. Rate of increase in the oxygen content of a pelleted Pt/Pd/Rh/Ce/A l2Os catalyst in lean exhaust at a space velocity of 110,000 h 1 (STP) and a catalyst inlet temperature of 680 K...

Fig. 11. Simulation of y versus x for the Beaumont T-2 kiln operating with conventional green silica-alumina catalyst. Computed results are given by the solid curve. The observed values, obtained fix>m a vertical traverse, are given by the points. The operating conditions were as follows flow of air up—23,500 scfm (665 semm) flow of air down—13,600 scfm (385 semm) air temperature at inlet—120°F (4 >°C) O2 in air to kiln—21% catalyst circulation rate—348 tons/hr (3.16 x KF kg/hr) catalyst inlet temperature (1-ft level)—900°F (482°C) coke on catalyst (1-ft level)—1.5%.

Computer solutions of the set of Eqs. (29)-(31) and (33) were obtained with a and AHf typical of those measurements on operating kilns, since the kinetics of the conversion of CO to CO2 had not been included into the model at this time. A low catalyst inlet temperature is used to show more clearly the effect of fast coke on kiln performance. Figure 18 shows the coke versus distance along the kiln for the fast and slow coke in the plume... 

Fig. 48. Mean error for the simulation of the NOx conversion at steady-state and constant urea dosing conditions as a function of exhausts mass flow and catalyst inlet temperature. Reprinted with permission from SAE Paper 2005-01-0965 2005 SAE International (see Plate 6 in Color Plate Section at the end of this book).

The catalyst emerging from the bottom of the reactor passes through a depressuring pot, and the steam that escapes from the catalyst is removed by a small jet condenser. Completeness of the purge is checked by inspecting the steam condensate for traces of oil. The temperature of the catalyst leaving the reactor is of the order of 875 F. (with a catalyst inlet temperature of 1000°F.), and carbon content is of the order to 2 to 4 wt. %. 

Figure 1 5. Conversion of carbon monoxide, gaseous hydrocarbons and sulfur dioxide reached over a diesel catalyst with and without measures to suppress the formation of sulfates, as a function of the exhaust gas temperature (monolith catalyst with 62 cells cm dedicated diesel washcoat formulations with platinum at a loading of 1.76 g I" diesel engine test bench light-off test at a space velocity of 120000 N1 F h diesel engine bench aging procedure for 100 h at a catalyst inlet temperature of 773 K).

The activity of the fresh and aged catalysts for CO, HC and NO ahatment was measured in a synthetic exhaust gas which simulated reaction conditions around the stoichiometry (R=l) with a pulsation frequency of IHz and an amphtude of 0.05. The TWC performance was measured with a catalyst inlet temperature of 450°C. The light-off performance was determined in experiments where the exhaust gas temperature at the catalyst inlet was increased continuously. 

Since the warm-up characteristic of a catalyst is an important consideration in auto exhaust application, the conversion of nitric oxide as a function of catalyst inlet temperature was studied for the virgin ruthenium and N-2 catalysts. The N-2 catalyst was more active (Figure 4). 

Three-Way Conversion (TWC) Catalyst. TWC-1 was evaluated on the same test unit with the catalyst inlet temperature raised to 650°C. The conversion of all three pollutants over a virgin catalyst is shown in Figure 11. The conversions of carbon monoxide and hydrocarbon at nominal A/F ratios much less than stoichiometric must be attributable mostly to steam reforming since the oxygen available was not sufficient to account for the observed conversion levels. This activity was lost... 

This table gives the test segment, its time interval and the associated maximum catalyst inlet temperature. Also shown are the corresponding % removal of HC and CO. The ramp segment (18 min. total) is broken down into each of the first 5 one min. intervals and the last 13 min. interval. Also shown is the % removal of HC and CO totalized for the overall storage + ramp segments of the test. 

Several strategies have been proposed in order to reduce the quantity of these pollutants and among them the use of the diesel oxidation catalyst appeared to be the most adequate [5]. The main role of this catalyst is to produce a complete oxidation of the heavy hydrocarbons and particulates to CO2 and water before release to the atmosphere. However, its efficiency is limited by the light-off temperature, that is, the temperature below which the oxidation is kinetically limited. Figure 18.1 shows the relation between the efficiency and diesel oxidation catalyst inlet temperature. 

Figure 18.1 The relation between the efficiency and diesel oxidation catalyst inlet temperature. EGR exhaust gas recirculation RME rapeseed methyl ester GTE gas-to-liquid. (Reprinted with permission from Ref. [5]. Copyright 2014, American Chemical Society.)...

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