Abstract

Increased energy conservation comes from broadscale technological progress such as a mix of better hardware, improved catalysts, computer process control, and optimized design. These cause energy efficiency to improve in times of both rising and falling energy prices. In times of rising energy prices, the trade of capital for energy is also important. Principal elements of energy efficient design are optimization of separation systems, including distillation and other techniques; heat-exchange technology; refrigeration; pressure drop; and steam and condensate systems.

An overall process energy balance serves as a framework during design and after start-up to optimize energy usage. A more fundamental analysis stresses minimizing the loss of work potential. In separation, efficiency results from low driving forces achieved by multistage processes, hence distillation is dominant. Special separations are usually only economical when removing a relatively dilute component. Heat interchanger capital, together with T and P costs, dominates many process. T has a greater economic impact on the cost of the heat-exchange surface than does P. Methods are given for T and P selection. Energy efficiency needs to be carefully integrated with the process to maintain reliability and safety.