Catalytic activity testing

Catalytic activity tests have been performed in a quartz microreactor (I.D.=0.8 cm) filled with 0.45 g of fine catalyst powders (dp=0 1 micron). The reactor has been fed with lean fiiel/air mixtures (1.3% of CO, 1.3% of H2 and 1% of CH4 in air resp ively) and has been operated at atmospheric pressure and with GHSV= 54000 Ncc/gcath The inlet and outlet gas compositions were determined by on-line Gas Chromatography. A 4 m column (I D. =5mm) filled with Porapak QS was used to separate CH4, CO2 and H2O with He as carrier gas. Two molecular sieves (5 A) columns (I D.=5 mm) 3m length, with He and Ar as carrier gases, were used for the separation and analysis of CO, N2, O2, CH4, and H2, N2, O2 respectively... 

Activity tests - Catalytic activity tests were carried out in 70 or 300 ml stainless steel stirred autoclaves (Parr Co.) at a stirring rate of 1000 rpm. Reaction conditions are given in the Tables. 

A structured ruthenium catalyst (metal monolith supported) was investigated by Rabe et al. [70] in the ATR of methane using pure oxygen as oxidant. The catalytic activity tests were carried out at low temperature (<800 ° C) and high steam-to-carbon ratios (between 1.3 and 4). It was found that the lower operating temperature reduced the overall methane conversion and thus the reforming efficiency. However, the catalyst was stable during time on-stream tests without apparent carbon formation. 

The catalytic activity tests were carried out under different operating conditions, by changing the GHSV and the feed ratios 02 CH4 and H20 CH4 over the ranges of values 0.59 < 02 CH4 < 1.36, 0< H20 CH4< 1.33 and 10000h" [Pg.306]

In order to establish the influence of preheating of the reactants on the ATR reactor performance, catalytic activity tests were carried out with and without preheating the reactants. For the tests performed with air and water preheating, two heat exchangers were integrated in the previous version of ATR reactor. 

The results of catalytic activity tests carried out without preheating are shown in Figure 9.10. 

Figure 9.10 Results of CH4 ATR catalytic activity test on a Pt/Al203 catalyst without preheating of reactants.

With regard to the operating conditions, catalytic activity tests were carried out at fixed 02 CH4 and H20 CH4 feed ratios of 0.56 and 0.49, respectively, while the space velocity was varied from GHSV = 45 000-90 000 h. ... 

The results of catalytic activity tests are reported in Figure 9.13a in terms of the temperature profile as a function of the catalyst bed length and in Figure 9.13b in... 

Figure 9.13 Temperature profile along the catalytic bed (a) and CH4 conversion, H2 concentration and H2 throughput per unit catalyst volume (b) in CH4 ATR catalytic activity tests carried out at high space velocity.

In order to investigate the performance of the ATR7B monolith at lower temperatures, other catalytic activity tests were carried out [98], the results of which are reported in Figure 9.14. The experimental conditions were changed in order to achieve stable low-temperature reactor behavior. 

O2/CH4 00, H2O/CH4 (yl, GHSV Figure 9.14 Results of CH4 ATR catalytic activity tests on noble metal-based monolith at lower temperature. 

Correlation between the two observed Mn species and catalytic activity properties was attempted. For this purpose, turnover frequencies (TOF) referred to the bulk content of the different Mn species were derived from the results of catalytic activity tests in CH4 combustion. TOF referred to Mn in Al(2) site was found to be almost constant on varying the overall Mn content. This suggested a possible correlation between catalyst activity and this Mn species. However, an alternative correlation was found by normalizing the catalytic activity to the surface area. Such normalized activity correlated well with the overall Mn content. No further evidence was found in favor of either these two alternatives, so that no definitive conclusion could be drawn. 

Addition of flourine to H-mordenite enhanced considerably the acid strength of this catalyst but decreased the ratio of Brpnsted to Lewis acidity (167). Using IR spectroscopy of adsorbed pyridine, X-Ray diffraction, catalytic activity tests for cumene cracking, and microcalorimetric measurements of ammonia adsorption, it was shown that some of the acidic hydroxyl groups were substituted with fluorine and that the inductive effect of fluorine increased the acid strength of the remaining hydroxyl groups. 

Radiation Dose (ev/gm) Dose rate (ev/gm, sec) Time between irradiation and catalytic activity test (days) Change in activity from irradiation (%)... 

Engine tests are performed with an engine mounted on a computer-controlled brake, with an exhaust gas cooler or heater installed in between the engine outlet and the catalytic converter inlet. Several catalytic activity tests can be performed using this setup. 

Results of catalytic activity tests of catalysts C together with some structural characteristics are presented in Table II. 

A number of specimen leached at the optimum leaching conditions, were used in the catalytic activity tests. The tests were accomplished in a laboratory scale apparatus. A gas mixture, which simulates the stoichiometric composition of common car emissions (0.8%CO,... 

Catalytic activity test was performed in a fixed-bed flow reactor at atmospheric pressure and temperature range from 140 to 300 °C. The following conditions were applied 0.5 cm of catalyst bed volume, 4000 h of space velocity, 31.1 kPa of partial pressure of water vapor, and the reactant gas mixture contained 4.494 vol.% CO in argon. The CO and CO2 content was analyzed on URAS-3G and URAS-2T (Hartmann Braun AG) gas analyzers and the catalytic activity was expressed by degree of CO conversion. 

Figure 1. Experimental apparatus used for catalytic activity tests.

In a typical procedure, benzene was stirred with freshly activated catalyst sample. Prior to activation, the catalyst samples were ground and sieved, and a fraction of 315-800 pm was used for each catalytic activity test. Catalyst samples were activated by heating in an oven at 185T for 2 h prior to catalyst activity tests. An aliquot of bcn/yl chloride was then added and the reaction mixture stirred for 15 min at room temperature. Mass ratios of the reactants and catalyst were benzyl chloridc/catalyst = 10 and bcn/cne/benzyl chloride = 3.5-4. An excess of benzene resulted in the formation of diphenylmethane as the dominant product. The follow ing reactions occur in the system ... 

The fresh (FS), coked (CS) and regenerated (RS) samples were characterized by magnetic measurements [2], scanning electron microscopy (STEM/EDX), temperature programmed techniques (TPR, TPO) and catalytic activity tests. 

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