Testing IH Instrumentation: Analysis of 1996-1998 Tank Ventilation Data in Terms of Characterizing a Transient Release

Droppo, James G.

Pacific Northwest National Laboratory (U.S.)

关键词: Vapor;    Ventilation Ventilation;    Air Pollution Monitors;    Underground Tank, Hanford;    Performance Testing;   

DOI  :  10.2172/860084
RP-ID  :  PNNL-14765
RP-ID  :  AC05-76RL01830
RP-ID  :  860084

美国|英语

来源: UNT Digital Library

【 摘 要 】

An analysis is conducted of the 1996-1998 Hanford tank ventilation studies of average ventilation rates to help define characteristics of shorter term releases. This effort is being conducted as part of the design of tests of Industrial Hygiene’s (IH) instrumentation ability to detect transient airborne plumes from tanks using current deployment strategies for tank operations. This analysis has improved our understanding of the variability of hourly average tank ventilation processes. However, the analysis was unable to discern the relative importance of emissions due to continuous releases and short-duration bursts of material. The key findings are as follows: 1. The ventilation of relatively well-sealed, passively ventilated tanks appears to be driven by a combination of pressure, buoyancy, and wind influences. The results of a best-fit analysis conducted with a single data set provide information on the hourly emission variability that IH instrumentation will need to detect. 2. Tank ventilation rates and tank emission rates are not the same. The studies found that the measured infiltration rates for a single tank are often a complex function of air exchanges between tanks and air exchanges with outdoor air. This situation greatly limits the usefulness of the ventilation data in defining vapor emission rates. 3. There is no evidence in the data to discern if the routine tank vapor releases occur over a short time (i.e., a puff) or over an extended time (i.e., continuous releases). Based on this analysis of the tank ventilation studies, it is also noted that 1) the hourly averaged emission peaks from the relatively well-sealed passively-vented tanks (such as U-103) are not a simple function of one meteorological parameter – but the peaks often are the result of the coincidence of temporal maximums in pressure, temperature, and wind influences and 2) a mechanistic combination modeling approach and/or field studies may be necessary to understand the short-term temporal characteristics of transient releases - This requirement has implications in both the design of IH field tests and in understanding transient plumes during the times that worker complaints were recorded.