Reliable modelling of the sulphur properties to calculate the process parameters of the Claus sulphur recovery plant

Abstract

In order to handle the overwhelming effects of the removed hydrogen sulphide (H₂S) from natural gas and industrial waste gases on the environment, H₂S can be converted to elemental sulphur. Among the available processes for sulphur recovery, the most widely employed process is a modified Claus process. In this work, first, least square version of support vector machine (LS-SVM) approach is utilized for determining the properties of sulphur including heat of vaporization, heat of condensation (S₆, S₈), heat of dissociation (S₆, S₈), and heat capacity of equilibrium sulphur vapours as a function of temperature. An illustrative example is given to show the usefulness of the presented computer-based models with two parameters for designing and operation of the Claus sulphur recovery unit (SRU). According to the error analysis results, predicted values by the proposed intelligent models are in excellent agreement with the reported data in the literature for the aforementioned sulphur properties where the coefficient of determination (R²) is higher than 0.99 for all developed models. The average absolute relative deviation percent (%AARD) is less than 1.3 while predicting the heat capacity of equilibrium sulphur vapours. Other proposed models' predictions show less than 0.2% AARD from the target values. In addition, a mathematical algorithm on the basis of the Leverage approach is proposed to define the domain of applicability of the developed LS-SVM models. It was found that the presented models are statistically valid and the employed data points for developing the models are within the range of their applicability.