Book excerpt: In Optimization of Industrial Unit Processes, the term "optimization" means the maximizing of productivity and safety while minimizing operating costs. In a fully optimized plant, efficiency and productivity are continuously maximized while levels, temperatures, pressures, or flows float within their allowable limits. This control philosophy differs from earlier approaches - where levels and temperatures were controlled at constant values, and plant productivity was only an accidental, uncontrolled consequence of those controlled variables. With this approach, the sides of a multivariable control envelope are the various constraints while inside the envelope the process is continuously moved to maximize efficiency and productivity. Because one must understand a process before one can control it (let alone optimize it), Optimization of Industrial Unit Processes discusses the "personality" and characteristics of each process in term of its time constants, gains, and other unique features. This book provides information for engineers who design or operate industrial plants and who seek to increase the profitability of their plants. It recognizes that all industrial processes involve operations such as material transportation, heat transfer, and reactions. Therefore each plant consists of a combination of basic unit operations and can be optimized by maximizing the efficiency, and minimizing the operating cost, of the individual unit operations from which it is composed. Optimization of Industrial Unit Processes discusses real world processes - where pipes leak, sensors plug, and pumps cavitate - offering practical solutions to real problems. Each control system described in the book works, illustrating the state of the art in controlling a particular unit operation. This second edition reflects the continual improvement and evolution of control systems as well as anticipates future advances. Bela G. Liptak speaks on Post-Oil Energy Technology on the AT&T Tech Channel.