Applications of new high resolution evolved-gas analysis systems for the characterisation of catalysts using rate-controlled thermal analysis

Use of Solid Insertion Probe Mass Spectrometry and Constant Rate Thermal Analysis in the Study of Materials: Determination of Apparent Activation Energies and Mechanisms of Solid-State Decomposition Reactions

“…The system utilizes software, developed by the authors and running under Windows 95 (Microsoft), for data acquisition and control, which provides a range of experimental techniques including conventional linear heating and a wide variety of SCTA methods such as CRTA . Voltages corresponding to the relative concentration of the species being measured are acquired from the MID unit via a 16-bit analog-to-digital converter (ADC, Strawberry Tree Dyna-Res).…”

“…In CRTA the reaction is forced to proceed at a constant (and low) reaction rate by appropriate control of either the temperature 8 or, for certain systems, the concentration of a reactant gas . Thus, rather than setting the heating rate at a predetermined value, the reaction rate is predetermined . Adopting this approach enables temperature and pressure gradients to be greatly reduced throughout the sample, minimizing the effects of heat and mass transfer. ,, …”

“…15 Thus, rather than setting the heating rate at a predetermined value, the reaction rate is predetermined. 16 Adopting this approach enables temperature and pressure gradients to be greatly reduced throughout the sample, minimizing the effects of heat and mass transfer. 3,8,17 CRTA can be modified to give the "rate-jump" method for determining kinetic parameters.…”

“…The system utilizes software, developed by the authors and running under Windows 95 (Microsoft), for data acquisition and control, which provides a range of experimental techniques including conventional linear heating and a wide variety of SCTA methods such as CRTA. 16 Voltages corresponding to the relative concentration of the species being measured are acquired from the MID unit via a 16-bit analog-to-digital converter (ADC, Strawberry Tree Dyna-Res). These values, together with the sample temperature, are processed and stored by a PC (P-II, 233 MHz, Viglen) and the required heating rate (for CRTA experiments) calculated, using a three-term PID algorithm to ensure good control of the reaction rate, as a series of temperature set points.…”

Development of a universal constant rate thermal analysis system for being used with any thermoanalytical instrument

“…Sample Controlled Thermal Analysis (SCTA) methods have proven to be more effective than conventional rising temperature experiments for obtaining reliable kinetic data of thermal decomposition of solids (25)(26)(27)(28)(29)(30)(31)(32)(33)(34)(35)(36)(37)(38)(39)(40)(41)(42). This is because the ability of SCTA for performing a direct or indirect control of both the partial pressure of the gases generated in the reaction and the heat evolution proportional to the reaction rate, minimizing the influence of heat and mass transfer phenomena on the forward reaction.…”