ESTIMATION OF CRITICAL PROPERTIES FOR SUBSTANCES

This article has tried to assess different approaches to critical properties estimation of different substances critical properties studied in this article include: critical temperature, critical pressure and critical volume. Different methods have been presented for estimating substances so far, methods with absolutely different ways of functioning. As the matter of fact the present article is a general assessment and categorization of these methods and equations. This categorization has first been presented by authors. Methods of group contribution and riazi have been studied in this article. In riazi method which is the last method presented in the article, there is no need to knowledge of the chemical and molecular structure of combinations and having known only the normal boiling point and the density, one can estimate the critical properties while in group contribution approach which includes different methods it self, molecular combinations and the chemical structures ought to be exactly defined, every single one of group contribution methods contributes a variety of substances combinative and properties as well.