Process systems are a complex set of components, behaviors, and relationships that make reorganization and, as a result, analyze their challenges and provide appropriate responses difficult. Process Systems Engineering (PSE) uses theories of systems and engineering systems in processes to make a better understand of these systems. In addition, based on sufficient knowledge they examine different response solutions to new challenges of these systems and selects the optimal response among different solution alternatives. The fourth generation of PSE, using emerging tools of the Fourth Industrial Revolution, has taken a step in increasing the depth of this recognition and the quality of its response in the development of oil, gas, and petrochemical smart industries. In this article, first, the comprehensive theory of systems and engineering systems applied on the process approaches based on the characteristics of these systems, and then the scope of activities and the role of process engineering systems as decision-making in solving the challenges of the oil, gas and petrochemical industries are reviewed and updated. In addition, this new mechanism for solving and responding to process challenges by this group of engineers is explained and the role of emerging tools resulting from the Fourth Industrial Revolution in improving the speed and accuracy of this response is discussed. Also, key technologies of the Industrial Revolution 5.0 are discussed and the prerequisites for the next generation of process engineering systems are addressed.