Grand challenges in chemical engineering.

Abstract

Chemical Engineering—also referred to as process engineering—is the branch of engineering applying physical and life sciences, mathematics and economics to the production and transformation of chemicals, energy and materials. Traditionally, it consists of heat, mass and momentum transport, kinetics and reaction engineering, chemical thermodynamics, control and dynamic simulation, separation, and unit operations. Conventionally developed and applied for the petro-chemical and the heavy chemical industry, chemical engineering has rapidly evolved with applications in a multitude of fields, including climate change, environmental systems, biomedical, new materials and complex systems. In 2003, the report “Beyond molecular frontiers: challenges for chemistry sciences and chemical engineering” mandated by the National Research Council of the American National Academies and chaired by Professors Breslow and Tirrell was released (National Research Council, 2003). The study investigated the status of chemical science: where are we, how did we arrive at this state and where are we heading? It concluded that science has become increasingly interdisciplinary. It also identified a trend toward the strong integration from the molecular level to chemical engineering and “the emergence of the intersections of the chemical science with all the natural sciences, agriculture, environmental science and medicine as well as with materials science, physics, information technology and many other fields of engineering.” A decade later, this vision has been largely realized and so-called “molecular engineering” that integrates chemical engineering with all sciences is now a reality. These rapidly expanding intersections of a wide range of areas of science with engineering are the new Frontiers in Chemical Engineering. Frontiers in Science and Engineering are mobile, ever expanding in a nonlinear and stochastic fashion. Any attempt to map the frontiers of knowledge is a difficult exercise that is usually out of date before it is published. An arguably more profitable alternative is to challenge the frontiers: to push their boundaries until some reaction occurs: whether rejection by the community or some progress follows in incremental or quantum steps. Another approach to define the frontiers of chemical engineering is to consider the chemical reactions that have marked the development of humanity’s current standards of living and the topics currently critical to ensure that acceptable standards are distributed more equitably around the globe without catastrophic impact on global climate and ecosystems. What is the most important chemical reaction that has impacted humanity? And what will be the next one? What are the most significant chemical technologies needed to ensure expansion of acceptable living standards while minimizing environmental impact? To take just one of many possible candidates for the title of “Most Important Chemical Process,” the Haber-Bosch reaction, which produces ammonia by reacting atmospheric nitrogen with hydrogen, has allowed humanity to pass the 2 billion population barrier and reach the current global population of some 7 billion (Smil, 1999; Kolbert, 2013). Ammonia is a key ingredient in fertilizer for good plant growth. Until the advent of the Haber-Bosh process in the 1913, agriculture operated under nitrogen-limited conditions with the cultivation of arable lands sufficient to feed only 2 billion people. Developing low cost fertilizer has enabled a new era of growth in both crop yields and human nutritional standards by escaping the limitations imposed by natural nitrogen fixation processes. An agricultural revolution has been the result. Another example of chemical processes with wide social significance are the development of antibiotics, vaccines and immunology which have given mankind much better control over microbial pathogens, allowing longer and better human lives. Yet a third area of chemistry is our understanding of semiconductor materials and how to mass produce them with extraordinary precision that is the basis of modern microelectronics, computer science and the World Wide Web. These chemical and electronic technologies have effectively decoupled the memory/storage function of the human brain from its analytical capability, thereby liberating its powers to focus on creativity and connectivity in ways that previous generations could not imagine. Increasingly sophisticated application of mathematical principles to the phenomena of physics, chemistry and biological sciences, from the atomic level to intergalactic scales, enable us to better understand natural and anthropogenic phenomena and to either control them, or to prepare for changes which are beyond our control. Langer and Tirrell, from MIT and Caltech respectively, have pioneered an engineering approach to biomaterials for medical application, even pushing the boundary of oncology and tissue engineering (Langer and Tirrell, 2004; Karp and Langer, 2011; Schroeder et al., 2011). Bird et al. showed that molecular engineering of surface affects not only the behavior of liquid droplets with a surface at equilibrium,