Incinerability of Halon s and HCFC s Theoretical Calculations of DRE

1. Incinerability of Halons and HCFCsTheoretical Calculations of DRE Presenter: Dr. Charles W. Lamb CHARLES LAMB and Associates Coauthors: Dr. Barry Dellinger, Louisiana State University Mark Wagner and Robert Lanza, ICF International

2. This research conducted • At request of the U.S. EPA to determine thermal stability of five non-hazardous ODS (ozone depleting compounds) that have not been adequately tested in a U.S. destruction facility.

3. Ozone Depleting Substances (ODS) • The earth’s stratospheric ozone layer is a protective barrier that prevents excessive amounts of harmful ultraviolet radiation (UVR) from reaching the earth’s surface. • ODS are chemicals that destroy ozone in the stratosphere

4. Montreal Protocol • Signed by 180 countries (including the U.S.) • Sets a phaseout schedule for the production and consumption of ODS beginning with bromofluorocarbons (halons) and chlorofluorocarbons (CFCs), and later methyl bromide and hydrochlorofluorocarbons (HCFCs). • Recommends only technologies for halon destruction based on actual trials of ODS destruction units using halons • Units undergo expensive testing using halons and ODS as POHCs in their performance tests to physically measure the DREs achieved

5. U.S. Clean Air Act (CAA) • Amended in 1990 to include Title VI, Stratospheric Ozone Protection • Federal regulations on the production, use, reclamation, and destruction of • class I ODS (e.g., CFCs), and • class II ODS (e.g., HCFCs, halons), and their substitutes.

6. U.S. Clean Air Act (CAA) • Production of ODS is being ended according to a step-down schedule • There are no current federal, state, or local regulations in place that require • The removal of ODS from equipment • The destruction of any removed ODS • Some stockpiled ODS could be made available for destruction, particularly if incentives were provided

7. ODS Destruction in HWCs • Montreal Protocol • Specifies the processes which should be used for ODS destruction, including incinerators and cement kilns • Requires 98% DRE • All known ODS destruction in the U.S. has occurred at RCRA-permitted HWCs.

8. Project Summary • Certain ODS are not on U.S. EPA’s thermal stability ranking system • Need to determine the thermal stability of ODS such as halon 1301 and HCFC-22 that have not been tested in a U.S. destruction facility. • Need to determine whether these compounds can be safely destroyed in an existing U.S. hazardous waste combustor (HWC).

9. Outline • Theoretical incinerability & DRE • Pseudo-first-order kinetics • Arrhenius parameters and equations • Halons (bromofluorocarbons) • HCFCs (hydrochlorofluorocarbons) • Rank in Incinerability Index • Potential PICs from incineration • By-products with ozone-depleting potential and/or global warming potential may form

10. Incinerability Index Ranked 1 - 320

11. DRE from Arrhenius Equation DRE = 100 (1-f) = 100 [1 – exp( -At exp(-E/RT))] where: DRE= destruction and removal efficiency, % f = fraction remaining undestroyed t = mean gas reaction time, s A = Arrhenius frequency factor, 1/s E= oxidation activation energy, kcal/mol T = absolute temperature, ºK

12. Calculate Time or Temperature Calculate the time required to achieve the given DRE at temperature T. t = - (ln f/A) exp(503 E/T) Calculate temperature, T T = 503 E(ln(-tA/ln f))-1

13. Arrhenius ParametersDerived from Theory and Database

14. Incinerability Rankings EstimatedRelative T to get 99% DRE in 2 secs

15. Temperatures for 99.99% DRE

16. DRE OK but what about PICs? • ODS can be effectively incinerated to 99.99% DRE in a properly designed and operated HWC. • However, questions remain: • What products of incomplete combustion (PICs) may be formed and at what levels? • What will their ozone-depleting potential (ODP) and global warming potential (GWP) be?

17. PIC? • For example, halon 1211 (CF2BrCl) would be expected to lose bromine and form a chlorofluorocarbon radical that could form an ODS compound that might survive the incineration

18. Thermal Stability • Stability due to carbon-halogen bond strengths: • Fluorine - high • Chlorine - intermediate • Bromine - low • The destruction pathway of halons and CFCs always involves the bromine or chlorine atoms but not the fluorine atoms.

19. PIC Formation • For example, incineration of HCFC-123 (CF3CHCl2) could form perfluroethane (CF3CF3) which is essentially un-incinerable • Possible production of thermally-stable PICs that have ozone-depleting or global-warming potential is a question that requires additional research

20. Conclusions • Study proves that these ODS can safely be incinerated in any existing HWC facility which has a proven DRE of 99.99% for at least one class I POHC. • This makes expensive performance testing of halons and HCFCs in a HWC unnecessary. • Possible production of PICs that have ozone-depleting or global-warming potential is an issue that needs to be further investigated; this will require additional theoretical and possible experimental evaluation

21. Thank you Charles W. Lamb, Ph.D. Phone (870) 862-2541 cwlamb@suddenlink.net