Antifoam degradation testing

Abstract

Thanks to Caitlin Wood for collecting and organizing the data that was collected during the experiments. Thanks to Tom White and Steve Crump of SRNL Analytical Development for analyzing the blended condensate samples to determine the concentrations of HMDSO, TMS and propanal. Thanks to Alex Nikolov and Darsh Wasan, inventors of the Antifoam 747, for advice and support during this testing. Thanks to Isaac Bodey for the prompt delivery of Antifoam 747 pails as needed for testing. Thanks to Momentive for supplying a sample of Silwet L-77.

Evaluation of Thermolytic Production of Hydrogen from Glycolate and Common Tank Farm Organics in Simulated Waste

“…The results of these tests are shown in Figure 3 Further HGR experiments were performed with TMS and PEO, both of which are known degradation products from hydrolysis of Antifoam 747. 16 P1S1-Test 8 was conducted at approximately 250 mg TMS per L of simulant and yielded an HGR of 4.0 ± 0.6 × 10 -7 ft 3 h -1 gal -1 , similar to the baseline values observed without added organics. Similar results were seen when testing at approximately 650 mg PEO per L of simulant (P1S1-Test 9), with HGRs remaining as low as 5.9 ± 0.9 × 10 -7 ft 3 h -1 gal -1 .…”

“…The incorporation of Tank 30 simulant data into the temperature-modified glycolate model shown in Equation [16] has minimal impact on the functional dependence of salt concentrations on HGR, with reaction order constants of sodium, nitrate, and hydroxide changing by -21%, -10%, and +4%, respectively. However, the values of the pre-exponential factor and the apparent activation energy are modified significantly (increasing from 8.934×10 2 and 64.4 kJ mol -1 to 6.262×10 5 and 82.3 kJ mol -1 , respectively).…”

“…These parameters agree more closely with the observations made by Hu (Ea = 89.6 kJ mol -1 ) 9 and Ashby (Ea = 113 kJ mol -1 ). 10 The results from all glycolate-containing simulant experiments are evaluated against the temperaturemodified glycolate expression (Equation [16]) in Figure 3-18. The data in Figure 3-18 exhibit an improved fit of glycolate HGR measurements to a model expression, with all but one of the experimental results falling within the 95% confidence limits of the temperaturemodified glycolate HGR expression.…”

“…The temperature-modified glycolate HGR expression given in Equation [16] may be simplified for ease of implementation. This expression is given in Equation [17].…”

Assessment of Methane Generation from the Thermolysis of Organics in Caustic Waste

“…As previously reported in Antifoam Degradation Testing SRNL-STI-2015-00352, Antifoam 747, used in the Defense Waste Processing Facility (DWPF), decomposes to form the flammable organic products hexamethyldisiloxane (HMDSO), trimethylsilanol (TMS), and propanal. 14 In limited testing, TMS has been detected in CSTF Tank 22 at 2.7 mg/L and in DWPF processing samples at 11 mg/L. 15,16 HMDSO and propanal were not detected in the Tank 22 sample and were near or below detection limits in DWPF samples.…”