NOVEL PULSE THERMAL-ANALYSIS METHOD AND ITS POTENTIAL FOR INVESTIGATING GAS-SOLID REACTIONS

The application of thermal analysis (TA) has been extended by developi ng a novel method, pulse thermal analysis (PTA). The method is based o n the injection of a specific amount of the gaseous reactant(s) into a n inert carrier gas stream and monitoring of the changes in the mass, enthalpy and gas composition resulting from an incremental extent of t he gas-solid reaction. PTA enables carrying out gas-solid reactions wi th a controllable reaction progress at the desired temperature. It pro vides the opportunity of simultaneous monitoring of changes in the com position of the gas and solid phases during the course of the reaction . PTA can also be applied for quantitative calibration of mass spectro metric signals in combined TA-MS systems. The beneficial features of t he new method for investigating reduction and oxidation of solids, het erogenous catalytic reactions, and for quantitative determination of t he evolved species, are illustrated using Various examples. (C) 1997 E lsevier Science B.V.