Analysis of Toluene Toxicity and Atmospheric Dispersion from an Organic Rankine Bottoming Cycle System. Final Report

摘要

It seems to be generally accepted that both neurological and histological changes due to toluene exposure are difficult to detect below the 100 to 200 ppM ranges, which are the current OSHA exposure limits. Adverse effects were noted in mammals in both inhalation and subcutaneous routes of exposure. Aquatic life is also affected with both teratogenic and lethal effects occurring as well as behavioral changes. Leaks from the Organic Rankine Bottoming Cycle facility were modeled in three scenarios. The first case assumed a leak rate of one pound per hour. This resulted in a maximum concentration of 0.1 ppM, which is below the odor threshold and several times below the occupational exposure for 8-hour limits. Case 2 was the worst case situation when the entire amount of toluene is lost within a relatively small period of time. With a wind speed of 7 m per sec at a distance of .2 km, the maximum concentration for a 15 min exposure would be 23.2 ppM. In the Case 3 analysis, all of the toluene escaped into the PCM building and then slowly dispersed from there. Depending upon the length of time the leak rate occurred, odors would be detectable up to 300 m from the plant and occupational exposure levels would be exceeded at distances ranging from 45 to 160 m away. In summary, the potential exposures to toluene of both human and natural populations is minimal, and would occur in most cases, at levels below accepted standards. (ERA citation 06:020846)