Chemical Reactions and Kinetics of CWA Simulants under Extreme Heating Conditions
Abstract
The United States faces a variety of threats from weapons of mass destruction, including chemical warfare agents (CWAs). Under controlled conditions, CWAs are destroyed in a furnace by exposing them to high temperatures for certain periods of time. However, in access-denied areas, explosive weapons may need to be used to destroy these agents. The conditions generated by using such weapons are very different than those in a thermal decomposition furnace – typically higher temperatures but for shorter periods of time. Also, these weapons may contain reactive materials that burn for an extended period of time and may contain metals that form oxides or halogenated oxides that form halogens. The responsible use of weapons for the destruction of CWAs requires detailed knowledge of their effect on and their interactions with the CWAs. In particular, the development of such weapons requires knowledge of the chemical reaction pathways, reactions products, and reaction kinetics that occur in the extreme conditions of an explosive fireball, including high temperature, rapid heating rates, variable heating rates, asymmetric heating rates, interactions with reactive compounds and aerosols from various combustion processes, a range of temperature and concentration gradients due to multi-room facilities, and potential post-operation neutralization at various surfaces, as well as a shockwave and associated pressure changes. Because of the dangers involved in working with chemical warfare agents, our work focuses on using well-defined CWA simulants with chemical properties similar to those of CWAs. Our goal is to provide DTRA with essential information about the decomposition chemistry of several CWA simulants, heated at high rates, under asymmetric heating rates, in the presence of reactive materials (Al and I2O5), and in the presence of potentially neutralizing surfaces (concrete and sand). Using a pyroprobe heater, capable of heating rates of up to 20,000 °C/s, we will rapidly heat the CWA simulants and then identify the decomposition products and the kinetics of these reactions using various time-resolved in-situ and ex-situ characterization techniques. In addition, we will attempt to use an optical trapping technique to place droplets of CWA simulants at specific distances from the pyroprobe heater, and at specific distances from reactive material particles before rapidly heating them to high temperatures. A successful completion of the proposed research would provide essential information for the design, modeling, and effectiveness prediction of c-WMD weapons, putting adversarial CWA targets at risk. The information includes the chemistry, decomposition channels including intermediate and final species, and kinetics (rate constants and activation energies) of CWA simulants under high heating rates, in the presence of reactive materials, and in the presence of potentially neutralizing surfaces. It would also include information about the effect of temperature and heating duration. This information can then be used to evaluate the potential toxicity of the reaction products and the potential efficiency of c-WMD weapons (i.e. how much CWA was destroyed).
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- May 26, 2016
- Source ID
- HDTRA11610034
Entities
People
- Hergen Eilers
Organizations
- Defense Threat Reduction Agency
- Washington State University