1 Introduction

Crude petroleum has been explored, extracted and processed for thousands of years. ^[1] The modern petroleum industry as we know it, however, is just over a hundred years old. The processing of crude oil into various products, by-products, charge-stocks for petroleum-based finished products and petrochemicals has been determined by the ever-changing demand of the product slate and new products or processes. Historically, the petroleum industry is, perhaps, the single industry having had the greatest impact on the development of Chemical Engineering as a discipline. It is definitely a case where technology has preceded engineering science!

The use and application of thermodynamics of petroleum fluids encompasses all facets of the petroleum industry, ranging from production and refining of crude oil to processing of petrochemicals. This chapter is limited to a review of the most widely used thermodynamic methods in the petroleum refining industry, together with a discussion on a few recent developments. The chapter provides a single source of easily accessible relevant information.

Perhaps the most important thermophysical properties required in petroleum refining for rating as well as process and equipment design are enthalpy and vapor liquid equilibria (fugacities). Enthalpies and fugacities often provide sufficient information to calculate mass and energy balances across most unit operations in a refinery. Since crude oil is an undefined, wide-boiling mixture of many different types of hydrocarbons ranging in carbon numbers extending to 70 or beyond, conventional thermodynamic methods used for property prediction of pure components or well-defined mixtures...