Process Integration: Pinch Analysis and Mathematical Programming - Directions for Future Development

Abstract

Abstract Numerous studies have been performed process systems engineering field for improving the efficiency of supplying and using energy, water and other resources and consequently for reducing the emissions of greenhouse gases, volatile organic compounds and other pollutants, accumulating a significant body of methods, applications and results. It has become apparent that the resource inputs and effluents of industrial processes and the other units including the business centres, civic objects and even agricultural plants can and are often connected with each other. Most industrial plants and the other units throughout the world still use more energy and water than necessary, they are proven cases in the range 20 – 30 %, emitting too large volumes of Greenhouse Gases and other pollutants. Water-saving measures and the reuse of water may reduce groundwater consumption by as much as 25 – 30 %. Usually reducing resource consumption is achieved by increasing internal recycling and the reuse of energy and material streams. Projects for improving process resource efficiencies can be very beneficial and also potentially improve the public perception of the companies. Motivating, launching and carrying out such projects, however, involve appropriate optimisation, based on adequate process models, applied within the framework of appropriate resource minimisation strategies and procedures. Process Integration supporting process design, integration and optimisation has been around for nearly 45 years. It has been closely related to the development of process systems engineering, as well as utilising mathematical modelling and information technology. In the broader sense Process Integration methods can be classified into those relying on process based insight and targeting on the one hand, mainly employing targeting, heuristics and artificial intelligence—AI. On the other hand are the methods employing detailed mathematical models usually implemented as algebraic models with embedded superstructures in the case of process network synthesis. The methods relying on thermodynamic insights have been first published in the early 1980-s (Linnhoff and Flower, 1978) as well as those using mathematical programming—MP (Papoulias and Grossmann, 1983). There can also be a combined approach (Klemes and Kravanja, 2013). On the one hand, the concept relying on thermodynamic and/or physical insights using the well-known Pinch Analysis has been the more widely accepted in both academia and industry. Process Integration has thus converged towards two schools of thought, the thermodynamic based (Pinch) and the mathematically based MP, each having its own advantages and drawbacks. The thermodynamic school has mostly preceded that of the MP in generating ideas based on engineering creativity. The MP school has enacted its ideas and described them as explicit mathematical models for solving advanced PI problems. The collaboration between both approaches has been widening, taking from each other the more applicable parts. Its development has been accelerating as the combined methodology has been able to provide answers and support for important issues regarding economic development—energy, water and resources better utilisation and savings. This contribution is targeted towards a short overview of recent achievements and future challenges.