A New Approach to the Design and Optimization of Energy Efficient Chemical Processes

University Of Rhode Island, Kingston RI

Investigators

Abstract

ABSTRACT PI: Angelo Lucia Institution: University of Rhode Island Proposal Number: 0624889 Title: A New Approach to the Design and Optimization of Energy Efficient Chemical Processes Project Summary. This project is a new approach to the synthesis, design and optimization of energy efficient chemical processes. The rapidly rising costs of energy and U.S. dependence on foreign oil have prompted renewed interest in energy conservation and stewardship in both residential and commercial use. Energy use in the chemical industries is dominated by the cost of separation, particularly distillation. There are an estimated 40,000 distillation columns in the U.S. that consume approximately 18% of all of the energy in the manufacturing sector. Recent estimates put this use at 2.4 quadrillion Btu/yr. However, distillation is perhaps the most versatile means of separation and thus will continue to be used in some capacity to address a wide variety of separation needs. Therefore, new synthesis and design methodologies for overall energy efficiency should extend the current knowledge base for finding minimum energy requirements in separations to processes involving multiple units (e.g., hybrid separation schemes and reaction/separation/recycle processes). This is the approach adopted in this work. Intellectual Merit. The methodology proposed in this work uses a back-to-front design philosophy based on the novel concept of shortest separation lines. Through new global optimization formulations based on shortest separation lines, the methodology 1) Provides a concise and clear interpretation of minimum energy requirements in terms of the length of the separation line that is general and applicable to processes involving any number of components and unit operations. 2) Has analogous interpretation in hybrid separation synthesis and reactor synthesis and design. 3) Represents a unification of existing methodologies for finding minimum flows and minimum energy requirements in the presence of feed, saddle point or tangent pinch points. 4) Can identify correct processing targets for processes with multiple units (e.g., reactors, other separators) such that overall energy consumption is minimized. 5) Can easily find minimum energy solutions that do not correspond to separation pinch points. 6) Can be readily combined with other synthesis methods such as the attainable regions approach for reactors for the simultaneous design of energy efficient multi-unit processes. 7) Establishes conditions under which reverse separation results in a reduction in energy consumption. 8) Can (and will) be used to establish that longest and shortest separation lines are unifying geometric principles for the design of energy efficient chemical processes. 9) Provides a new intuitive methodology for teaching, practice, and dissemination of various aspects of energy efficiency in process design that can be understood by practitioners and the general public alike. Broader Impacts. The project will be providing 1) Educational modules that are easily incorporated within mentoring programs at the high school level and courses that have an energy component (e.g., undergraduate mass transfer and stage-wise separations, capstone design courses, process control, graduate level design). 2) Inner-city Rhode Island high school students from underrepresented groups with experiences in research important to society (i.e., energy conservation) and by exposing them to careers in chemical engineering. 5) Broad dissemination of novel research concepts and results through visits and public lectures at high schools as well as publications in archival journals and conference proceedings as well as oral and poster presentations at national and international conferences, and seminars at other academic and industrial organizations. 6) A means of achieving potentially substantial reductions in energy use throughout the chemical industry for the overall benefit of society.