Catalyst activity test

The methodology devised for model development is shown in Fig. 7. Data for developing the model come from SCAT (simulated catalyst activity test,... 

SCAT simulated catalyst activity test, i.e. a microreactor test... 

The object of this review is threefold (1) to discuss the various characterization techniques which have been applied to this catalyst system, (2) to relate what each technique reveals about the nature of the catalyst, and (3) to present an overall picture of the state of the catalyst as it now appears. We will not discuss the vast literature on catalyst activity testing, kinetics, or mechanisms here. These are subjects for review themselves. However, we will mention some selective catalyst activity tests which were designed to give some fundamental insight into the catalyst state or active sites present. Also, we will not discuss in detail the considerable work reported on pure compounds (unsupported) of molybdenum, cobalt, and/or aluminum but we will have occasion to compare some of their properties to our catalyst systems to assess to what degree they may be present in the catalyst. 

Figure 1. Schematic drawing of catalyst activity test unit.

Catalyst Activity. Fig. 3 shows the results of the catalyst activity test. The reaction was carried out at standard conditions consisting of a mean catalyst bed temperature of 538°C, atmospheric pressure and LHSV of 2h. The left graph indicates the results for conversion, total aromatics and BTX yields versus time on... 

The most satisfactory and meaningful catalyst activity tests are those involving the cracking of a standard cracking stock in small-scale static-bed reactors. Small laboratory-scale fluidized-bed test units have been described, but generally speaking these are more difficult to operate satisfactorily than fixed-bed units. Powdered catalysts are generally tested in pelleted form or in a nonfluidized static bed of powder. 

Design, construct, test, and integrate the pilot-scale pyrolyzer and the pilot-scale steam reformer, and begin long-term catalyst activity testing. 

N20-decomposition was employed as a model reaction to test the derived Fe-zeolite catalysts. Activity tests were carried out in a parallel-flow reactor system, which typically consumes 50 mg of catalyst particles (125-250 pm). The catalysts were tested in pure N20/He conditions (4.5 mbar N2O) at a total pressure of 3 bar-a. The space time, W/F°(N20), was 900 kgxsxmoT (W is the catalyst mass and F°(N20) the molar flow of N2O at the reactor inlet). The products were analyzed by gas chromatography (Chrompack CP 9001) and continuously analyzed with a chemiluminescence NOx analyzer (Ecophysics CLD 700 EL). The catalysts were pretreated in He at 673 K for 1 h, and cooled down in the same gas to the starting reaction temperature. Typically, one hour ensures steady state operation for this reaction at the conditions described above. 

The reaction was carried out in both batch and distillation reactor. 0.5 g catalyst (0.2-0.3 mm grain) was used for the catalyst activity test in a stainless batch reactor with 6 1 ratio of methanol to propylene carbonate. After the reaction proceeded for 2h at 160°C under constant stirring, the reactor was cooled down to room temperature and the products were then analyzed on a gas chromatograph with a TCD after centrifugal separation from the catalyst. 

For initial catalyst screening purposes a standard laboratory flow setup was used. Typical test gas compositions for the catalyst activity tests were 1000 ppm NO and NH3, 5% O2 and balance Argon. An initial screening on SO2 oxidizing... 

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 lattice oxygen of chromium oxide may directly participate in the decomposition of PCE as confirmed by TPR, shown in Fig. 4. It can be also observed by a catalyst activity test without oxygen feed to the reactor system. When the feed of oxygen was terminated during the course of the reaction at steady state to distinguish the oxygen involved for the reaction, PCE conversion decreased inversely proportional to the feed concentration of PCE as shown in Fig. 5. The lower the feed concentration of PCE to the reactor, the longer the... 

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