Assessment of errors on the kinetic data by entropy generation analysis

Metal hydride systems are utilized in many practical applications such as hydrogen storage, heat pumps, etc. The establishment of a metal hydride system requires the expression of reaction rate for the first step design, from an engineering standpoint. However, improper experimental determination of intrinsic kinetics usually leads to significant errors in the kinetic data. This paper presents a novel methodology of estimating these errors based on the entropy generation analysis. For this purpose, numerical simulation is performed taking into account the experimental conditions for a real case. The results showed that if the operating conditions (i.e. hydrogen pressure, heat transfer coefficient) and the size of the experimental setup are not chosen properly, the kinetic data obtained from the experiments will be largely misled. Therefore it should be carefully taken into account in order to minimize the relative errors induced on the kinetic data.

► The second law of thermodynamics theory is applied to study the kinetics of LaNi5. ► Two-dimensional model for entropy production during the hydriding process. ► The entropy generation corresponds to the relative errors on the activation energy. ► The operating conditions have a great influence on the total entropy generation.