Case Studies

Reactive Distillation

In the November 1999 AIChE Annual Meeting, Professors M. Doherty and M. Malone of the University of Massachusetts Department of Chemical Engineering presented their findings on the topic "Recent Advances in Reactive Distillation." In comparing the traditional versus the reactive distillation methods, such as in the production of methyl acetate example below (click to enlarge), the latter methods have the advantage of being able to:

• Improve Selectivity
  - Reduce Raw Materials Usage
  - Reduce Byproducts Prevent Pollution
  
• Reduce Energy Use
  
• Handle Difficult Separations
  - Avoid Separating Reactants
  - Eliminate/Reduce Solvents
  
• Enhance Overall Rates
  
• "Beat" Low Equilibrium Constants
  

Example: Production of Methyl Acetate

Top of page

Reducing Automobile Emissions and Saving Energy

William Obenchain and Marcel van Schaik of the American Iron and Steel Institute, and Pete Peterson of the U.S. Steel Group conducted a case study on the UltraLight Steel Auto Body-Advanced Vehicle Concepts (ULSAB-AVC), in which reductions in automobile emissions and improvements in gas mileage were observed as a result of using lightweight steel in the construction of cars.

The ULSAB-AVC is a complete conceptual design for steel intensive compact and mid-size sedans. The designs were developed by a consortium of 33 steelmakers from around the world. The designs specify gasoline and diesel powered models; in the U. S. combined driving cycle the mid-sized sedan will achieve 52 miles per gallon when powered with a gasoline engine and 68 miles per gallon if equipped with a diesel engine. This equates to only 0.32 (diesel) - 0.38 (gasoline) lbs of CO₂ per mile.

ULSAB-AVC: Comparison of Mileage and CO₂ Emissions

In addition, the automobiles are designed to achieve "Five Star" crash safety rating based on the anticipated 2004 safety standards, and will cost no more to build than traditionally engineered vehicles. By comparison, the 2000 fleet of midsize automobiles in the USA averages 28.6 mpg (DoE Transportation Energy Data Book, 2001 Ed.) and is not designed to meet the same stringent safety requirements as ULSAB-AVC. The ULSAB-AVC utilizes advanced high-tech steels and modern engineering and manufacturing techniques that are available to automobile and auto parts manufacturers.

Top of page

Carl Houtman of the USDA Forest Product Service and of the University of Wisconsin at Madison conducted a case study on minimizing the use of hazardous chemicals in the paper industry. To eliminate the use of and exposure to hazardous chemicals in the bleaching process, a new delignification agent (a polyoxometalate, or POM) is used to provide the basis for closed-mill bleaching technology. This technology eliminates the use of a hazardous chemical while maintaining effective lignin removal. The two flow charts below (click to enlarge) compare the traditional bleach process and the new "green" process using POM.

Paper Bleaching: Comparison of Process Stream and Energy Inputs

Top of page

Minimizing Worker Exposure to Mist in the Auto Industry

Exposure to mist from machining fluids can cause serious health problems, including cancer, respiratory problems, and allergic reactions. To limit exposure from inhalation of this mist, Professors Manke, Gulari, and Smolinski of the Wayne State University Department of Chemical Engineering and Materials Science tested the effect of adding polymers to both water-based and straight-oil machining fluids. A cost-effective method of reducing mist from oil-based fluids has already been widely implemented in the auto industry. For water-based fluids, however, the economics of mist suppression techniques are not yet as favorable, and engineers continue to look for practical ways to meet this challenge.

For straight oil fluids, polyisobutylene (PIB) can be added to control mist. An addition of 70 ppm of PIB results in a 40% reduction in average mist levels and a 67% reduction in peak mist levels (click to enlarge following figures). This additive has been used extensively in auto manufacturing facilities. Its costs are relatively low and only weekly replacement is required.

Top of page

Reducing Worker Exposure to Solid Particulate

Using engineering controls to eliminate manual dumping of bags, as shown in the figures below, can substantially reduce exposure to particulates in the workplace and the need for personal protective equipment such as respirators.

Top of page

You will need Adobe Reader to view some of the files on this page. See EPA's PDF page to learn more.