Methanol catalyst test reactor

Dudfield et al. [88] presented results generated in the scope of the Mercatox program funded by the European Community aimed at a combined methanol steam reformer/combustor with consecutive CO clean-up by PrOx. First, various catalysts were tested for the reaction as micro spheres in a test reactor which was similar to a macroscopic shell-and-tube heat exchanger (Figure 2.57). 

Fuel flexibility of the fuel reforming subsystem was demonstrated using methane, propane, butane, methanol, ethanol, isooctane, and benchmark gasoline. A 1000-hour catalyst and reactor durability test was completed using benchmark gasoline. Warm transient response of less than 5 seconds was achieved for 10 to 90% of full reformer capacity. A three-fold increase in reformer productivity was achieved compared to the previous year, due to improved catalyst performance and more uniform flow within the reactor. Reactor concepts that would meet FreedomCAR s rapid start-up targets were developed. 

A prototype for a methanol reforming silicon reactor was designed at Lehigh University [11,12,31]. Their microreaction system, made of silicon wafers, consisted of four main components a mixer/vaporizer of methanol and water, a catalytic steam reformer with a copper catalyst, the combined water gas shift reactor-membrane (as mentioned before) and integrated resistive heaters, sensors and control electronics. The reformer was tested with a stainless-steel housing. The authors reported a conversion of 90% for methanol, which corresponds to a power output of 15 W. 

The viability of the Lurgi MTF process was first demonstrated at a unit operated jointly with Statoil at Statoil s methanol plant in Norway [49] from 2001 to 2004. The skid-mounted MTP unit comprised of three reactors used 360kg/day methanol feed per reactor. In 2003, to confirm the quality of the propylene obtained in the MTP demonsfration unit, samples were sent to Boreahs s hmovation center in Rpmiingen, Norway, where it was polymerized with Boreahs s Borstar process to a polypropylene that met all specifications, and converted into thermoformed cups. The results from the demonsfration and further tests proved that the MTP catalyst Ufe exceeds 1 year of operation. The results also showed that the zeoUte-based catalyst could be easily regenerated more than a dozen times. 

For a first test of the reactor and all associated service installations it is recommended that experiments for methanol synthesis should be carried out even if this reaction is not especially interesting for the first real project. The reason for this recommendation is that detailed experimental results were published on methanol synthesis (Berty et al, 1982) made on a readily available catalyst. This gives a good basis of comparison for testing a new system. Other reactions that have been studied in detail and for which the performance of a catalyst is well known can also be used for test reactions. 

In this study, we developed microchannel PrOx reactor to control CO outlet concentrations less than 10 ppm from methanol steam reformer for PEMFC applications. The reactor was developed based on our previous studies on methanol steam reformer [5] and the basic technologies on microchaimel reactor including design of microchaimel plate, fabrication process and catalyst coating method were applied to the present PrOx reactor. The fabricated PrOx reactor was tested and evaluated on its CO removal performance. 

A system has been constructed which allows combined studies of reaction kinetics and catalyst surface properties. Key elements of the system are a computer-controlled pilot plant with a plug flow reactor coupled In series to a minireactor which Is connected, via a high vacuum sample transfer system, to a surface analysis Instrument equipped with XFS, AES, SAM, and SIMS. When Interesting kinetic data are observed, the reaction Is stopped and the test sample Is transferred from the mlnlreactor to the surface analysis chamber. Unique features and problem areas of this new approach will be discussed. The power of the system will be Illustrated with a study of surface chemical changes of a Cu0/Zn0/Al203 catalyst during activation and methanol synthesis. Metallic Cu was Identified by XFS as the only Cu surface site during methanol synthesis. 

Initial tests using the pulse reactor described in this paper have been done on the selective oxidation of methanol to formaldehyde using molybdate catalysts. 

TO test the reactor and analysis system, pulses of methanol, singly, and completely deuterated methanol were led over the commercial Pe (MoO.) VtoO, catalyst and the two separate phases, m this way, we can check-3if a kinetic isotope takes place on the separate phases, and the measurements can be extended to a larger temperature range more readily than under steady state conditions. The pulses contained about 12% methanol in argon and 10% oxygen. 

Activity Measurements. To test catalytic properties of various samples partial oxidation of methanol to formaldehyde was studied in a flow micro-reactor operating under normal atmospheric pressure (10). For each run about 0.2 g of catalyst sample was used and the activities were measured at 173 C in the absence of any diffusional effects. The feed gas consisted of 72, 2 and by volume of nitrogen, oxygen and methanol vapor respectively. Reaction products were analysed with a 10% Carbowax 20 M column (2m long) maintained at 60 C oven temperature. 

Most industrial reactors and high pressure laboratory equipment are built using metal alloys. Some of these same metals have been shown to be effective catalysts for a variety of organic reactions. In an effort to establish the influence of metal surfaces on the transesterification reactions of TGs, Suppes et collected data on the catalytic activity of two metals (nickel, palladium) and two alloys (cast iron and stainless steel) for the transesterification of soybean oil with methanol. These authors found that the nature of the reactor s surface does play a role in reaction performance. Even though all metallic materials were tested without pretreatment, they showed substantial activity at conditions normally used to study transesterification reactions with solid catalysts. Nickel and palladium were particularly reactive, with nickel showing the highest activity. The authors concluded that academic studies on transesterification reactions must be conducted with reactor vessels where there is no metallic surface exposed. Otherwise, results about catalyst reactivity could be misleading. 

Furuta et al. tested a series of strong solid acids (alumina promoted sulfated zirconia, alumina promoted tungstated zirconia and sulfated tin oxide) for the transesterification of soybean oil with methanol at 200-300°C. Reaction yields over 90% were obtained for the alumina promoted tungstated zirconia at reaction times of 20 h using a flow reactor T = 250°C). The activity of the same catalyst was maintained for up to 100 h. 

Ziogas et al. [28] performed catalyst screening with this reactor with catalysts coatings, which were made of various base aluminas such as corundum, boehmite and y-alumina. Testing of Cu/Cr and Cu/Mn catalysts based on the different coatings for methanol steam reforming revealed differences in activity which were ascribed... 

The [PrOx 3] reactor (see Section 2.6.2) and an improved second version of it carrying also a different ratio of platinum and ruthenium on the catalyst were tested separately and switched in series by Dudfield et al. [88] prior to combining it with a 20 kW methanol steam reformer. The reactors had dimensions of 46 mm height, 56 mm width and 170 mm length, which corresponds to a volume of 0.44 dm3 and a weight of 590 g. They contained 2 g of catalyst each. 

Pfeifer, P., Schubert, K., Fichtner, M., Liauw, M. A., Emig, G., Methanol-steam reforming in microstructures difference between palladium and copper catalysts and testing of reactors for 200W fuel cell power, in Proceedings of the 6th International Conference on Microreaction Technology, IMRET 6 (11-14 March 2002), AIChE Pub. No. 164, New Orleans, 2002, 125-130. 

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