After investigating various options, engineers at Eli Lilly and Company in 1990 purchased five HP portable gas analyzers. They were to help locate specific sources of fugitive emissions at one of the company's major manufacturing plants and monitor the effects of emission control measures. The result: total fugitive VOCs decreased 86 percent over a two-year period.

Eli Lilly engineers at the site also credit the portable analyzers with an increase in product yield worth $1,000,000 a year. Improved solvent recovery contributes an additional $200,000 a month in savings.

The HP portable gas analyzer provides accurate answers in less than three minutes. It has a self-contained gas and power supply and weighs less than 25 pounds.

Emissions Data Needed Fast
When U.S. government regulations and permit requirements demanded increasingly more detailed solvent emissions data, engineers at Eli Lilly investigated various options to identify, quantitate, and reduce fugitive volatile organic compounds (VOCs) at the company's manufacturing and pilot plants.

Eli Lilly uses mass balances to track solvent emissions. Subtracting solvent output from input provides a gross account of solvent emissions, but the data are received too late for managing emissions. Eli Lilly engineers from the company's Engineering Technical Center reviewed various technologies, including Fourier-transform infrared, mass spectrometry, and field-portable gas chromatography. They decided to use HP portable gas analyzers to locate and reduce emissions at Eli Lilly's manufacturing plant for bulk pharmaceutical and animal health products in Clinton, Indiana.

Locating the Emission Sources
Samples were taken from heating, ventilating and air conditioning vents to detect specific sources of VOC emissions at the Clinton facility. Five portable gas analyzers placed strategically throughout the plant provided analytical results within two minutes, supplying 20 to 30 data points an hour. This information allowed plant operators to correlate emissions with specific parts of the manufacturing process.

Before the portable gas analyzers were used, mass balances for solvent vapor methylene chloride at Eli Lilly’s Clinton facility revealed rising emissions over an 18-month period and wide fluctuations from month to month.

By correlating the data gathered from the portable analyzers with specific steps of the manufacturing process, plant operators were able to reduce emissions by 86 percent, a number that Eli Lilly's associate engineering consultant Richard Lambert describes as "pretty conservative." In one building at the Clinton facility, methylene chloride emissions dropped from 2,000 pounds a day to 200 pounds a month.

High Return on Investment
The process of profiling buildings for emissions, charting the data, and correcting problems to reduce emissions continued for one year. The cost of the monitoring system using the gas analyzers was recovered in less than one month.

Chromatographic record of methylene chloride concentration in a typical building emissions profile.

An Excellent Reliability Record
In addition to fast and accurate analyses, other important considerations in selecting the HP portable gas analyzers were portability, low cost, ease of use, and reliability. Richard Lambert notes that operators at the plant have little time to care for the system. "The portable gas analyzers proved to be very reliable. Even with 262,800 injections a year, the analyzers rarely require maintenance. On four of the systems, we've replaced only two sample pumps and one detector since 1992."

After the successful experience at the Clinton facility, Eli Lilly engineers used the portable gas analyzer systems at plants in Belgium and Ireland with equally advantageous results.

Analytical graphics from Richard H. Lambert, et al., "Utilization of a Portable Microchip Gas Chromatograph to Identify and Reduce Fugitive Emissions at a Pharmaceutical Manufacturing Plant", Field Analytical Chemistry and Technology; by permission of John Wiley & Sons, Inc. All rights reserved.