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Crystallite Size Dispersion Metal Area Pulse Titration TPR / TPO / TPD ChemBET Pulsar -TPR/ TPD ChemBET Pulsar Automatic Chemisorption Analyzer TPR/TPD 2 Instrument Features The ChemBET Pulsar TPR/TPD represents the very best in catalyst characterization using automated flow methods of analysis. Fully automated analysis sequences are programmed using the TPRWin software. Titrations for metal area and dispersion determination use an automatic loop injector and automatic gas switching. Furnace temperature ramping provides for temperature programmed methods and sample preparation, both including rapid furnace cooling using forced air for higher throughput. The Pulsar uses a proven TCD detector both oxidation AND ammonia resistant, with stable current control for baseline stability and reproducible signals. Plumbed in stainless-steel for maximum chemical compatibility, the Pulsar is ideal for use with a wide range of gases. High-temperature quartz sample cells are standard, as is the in-cell thermocouple providing accurate sample temperature measurements. An optional quadrapole mass spectrometer is available allowing for species c@7?erentiation during temperature programmed analyses. Automation Interchangeable Injection Loop Calibration Automatic Titration Valve Bypass Valves Cell Sample Temperature Monitoring Vapor Trap "%?BCold Trap@??P 1100 oC Furnace, Software Controlled Automatic Switching between Multiple Gas Inputs Forced Air Cooling Valve Status Display Display Cover Rapid titration & extreme sensitivity. TPA overlays for easy comparison. ChemBET Pulsar Automatic Chemisorption Analyzer TPR/TPD 3 Specifications Automatic Injection Loop Automatic Gas Switching between 4 ports Automatic Forced Air Cooling of Furnace Calibration Port Quartz Glassware Self-sealing Sample Cell Holders Stainless-Steel Plumbing V ariable Gas Flow Rate Control Sample Cell Bypass I n-Line Cold Trap with Bypass Supplementary Outgas/ Preparation Station M ass Spec Connection Port High Temperature (350 oC) Heating Mantle High Temperature (1100oC) Furnace Cell Sample Thermocouple Capability (Automatic) Pulse Titration (metal area) Temperature programmed Reduction (TPR) Temperature programmed Desorption (TPD@??P Temperature programmed Oxidation (TPO@??P Temperature programmed Surface Reaction (TPSR) Gas Compatibility: Input Pressure (gauge): Gas Lines: Voltage: Frequency: Power: Mantle, Max Temp: Mantle Power: Furnace, Max Temp: Furnace Power: H 2, O 2, CO, CO 2, N 2O, SO 2, NH 3, N 2, Ar, Kr, He 70-140 kPa (10-20 psig) 5 x 1.5m 1/8” s.s. (supplied) 100 - 240 VAC 50/60 Hz 70 VA 350 oC 125 W 1100 oC 575 W Software Control Programming of the following actions creates a customized multi-step @5?u#macro`y? which automatically controls the analysis: Gas switching Manifold purge Start/stop signal acquisition Temperature ramping (by rate) Temperature ramping (by time) Multiple heating/cooling profiles Cooling fan on/off Pulse injection The following data are presented on screen in real time and automatically stored: TCD signal Sample temperature Time Utilities 1 2 1 2 Thermal Conductivity Detector: TCD Filaments: Furnace Cooling: Gas Input Ports: Loop Volumes Supplied: Dual-Filament Diffusion Type Oxidation and Ammonia Resistant Forced air (PC Controlled) 5 50, 100, 250 µL (others available) Hardware Features ChemBET Pulsar Automatic Chemisorption Analyzer TPR/TPD 4 Carbons, Fuel Cells, etc. Industrial Catalysts(eg. Hydrocracking, Hydrodesulfurization, Hydrodenitrogenation and Fischer-Tropsch@??P Supported Metals "%?B Reforming, Partial Oxidation, Hydrogenation, Automotive Exhaust, etc.@??P TPR: Temperature Programmed Reduction Many heterogeneous catalysts are used as the zero-valence metal, but start life as the oxide. An important factor in catalyst design and use is the ease of reduction of the metal oxide and TPR is a direct measure of that. A reducing gas mixture, say 2%-5% H 2 in N 2, flowing over the oxide will cause reduction at some point as the temperature is raised using a linear heating ramp. The signal caused by consumption of hydrogen represents the rate of reaction and goes through a maximum at a temperature that is characteristic of both the oxide and the heating rate. Repeating the same analysis on a fresh sample at a different heating rate is the means by which activation energy for the process can be evaluated. Low loadings of metal oxides, especially surface oxides, generate little water and a successful analysis can be done without trapping it. Larger amounts of moisture generated by the reduction of bulk oxides can be trapped prior to reaching the detector to leave a clean signal based solely on the change in hydrogen concentration. TPO: Temperature Programmed Oxidation Carbons and carbides are amenable to evaluation by careful oxidation while being heated. A stream of diluted oxygen (e.g. 2-10% O 2 in He) directed over the sample during a linear heating ramp generates a signal due to the loss of O 2 from the gas stream. The products of oxidation, CO and CO 2 , need not be trapped. The specially chosen filaments used in the Pulsar"tas TCD detector are resistant to oxidation and operate normally in the suggested gas mixtures. Different forms of carbon such as amorphous, nanotube, filament and graphitic, oxidize at different temperatures due to varying availability of reactive carbon-carbon bonds. In this way, fullerenes, soots, cokes on catalysts, etc can be quickly characterized and differentiated. Oxidation catalysts, e.g. those incorporating chromium, cobalt, copper and manganese, and redox supports like ceria can also be characterized by TPO. TPD: Temperature Programmed Desorption Species previously adsorbed can be desorbed into a stream of pure carrier gas to generate a characteristic finger- print. The most common application is ammonia TPD, by which one can evaluate relative acid site strength of, for example, zeolites. Basic sites can similarly be evaluated by TPD of carbon dioxide. Some materials may be characterized by decomposition, or dissociation, of the bulk solid, not merely by desorption from the surface. Such examples include carbonates resulting from CO 2 removal studies, hydrides used as potential hydrogen storage materials, etc. Pulse Titration: Quantitative Analysis This technique is used to determine the following data: (i) strong chemisorption uptake, (ii) active metal area, (iii) metal dispersion, (iv) average nanocluster (crystallite) size. After suitable in-situ preparation, which may be combined with TPR/TPO, the sample is automatically titrated with small, known volumes (pulses) of reactive gas. The detector senses the excess gas which does not react with the sample. The total volume of gas which does react with the sample is automatically determined by simple back calculation using TPRWin software. B.E.T. Surface Area: Physisorption The Pulsar can determine total (B.E.T.) surface area with remarkable sensitivity. By flowing various mixtures of nitrogen and helium over the sample cooled with liquid nitrogen, the surface area can be determined from 0.1 square meters upwards. Using mixtures of krypton and helium the limit of detection is extended down to 0.01 square meters. A single point B.E.T. result can be obtained in under ten minutes. TPRWin software records the signals automatically, computes the B.E.T. @5?u#C`y? constant, y-intercept, slope and correlation coefficient of the least- squares best-fit. Measurement Capabilities & Applications Zeolites (eg. FCC, Isomerization) Corporate Headquarters-USA Quantachrome Instruments a brand of Anton-Paar 1900 Corporate Drive Boynton Beach, FL 33426 © 2019 Quantachrome Corporation I10IP018EN-B Trademarks and registered trade mark are the property of their respective owners.Serving Porous Materials and Powder Characterization Needs Since 1968 ChemBET Pulsar Automatic Chemisorption Analyzer TPR/TPD
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Date d'upload du document :
mardi 12 janvier 2021