TRIAL BURN TECHNOLOGY FOR WASTE THERMAL PLANT

1. TRIAL BURN TECHNOLOGY FOR WASTE THERMAL PLANT 유동층공학 환경응용기술 연구회 1999. 12. 16 한국원자력연구소/핵화공연구팀양 희 철

2. Nuclear Fuel Cycle R&D Group, Korea Atomic Energy Research Institute Content • Trial Burn Concept • Trial Burn Technologies • Trial Burns of PAM system • Recommendations

3. Glossary APCE : Air Pollution Control Equipment DRE : Destruction and Removal Efficiency FWF : Final Waste Form HTM : High-temperature Metals LT : Low Temperature LTO : Low-temperature Organics PAM : Plasma Arc Melter PICs : Products of Incomplete Combustion PCC : Primary Combustion Chamber POHC : Principal Organic Hazardous Constituent SCC : Secondary Combustion Chamber TB : Trial Burn Nuclear Fuel Cycle R&D Group, Korea Atomic Energy Research Institute

4. Nuclear Fuel Cycle R&D Group, Korea Atomic Energy Research Institute Waste Thermal Plants • Conventional incinerators • Rotary kiln • Liquid injector • Controlled air • Fluidized Bed • Boilers • Melters • High temperature • Low temperature • Others • Molten salt oxidation • Wet chemical catalyst oxidation

5. Air Pollution Control System Waste To exhaust stack Sorting Flue gas Homogenizing Spent scrubber liquor to liquid treatment Incinerator Flue gas Fly ash Bottom ash Vitrifying Melter Slag forming additives Molten metal tap Slag tap Nuclear Fuel Cycle R&D Group, Korea Atomic Energy Research Institute Integrated Waste Thermal Treatment System

6. Nuclear Fuel Cycle R&D Group, Korea Atomic Energy Research Institute Objectives of Trial Burns • The trial burn serves two main purposes : • It demonstrates that the thermal system can meet all applicable regulations. • It establishes the conditions under which the combustor can meet the applicable regulations. • The data gathered from TBs must • Identify the specific operational parameters that affect each regulated environmental impact. • Establish the worst-case value for operational parameters (i.e., max. or min) • Ensure that all permit conditions are physically consistent with one another.

7. Nuclear Fuel Cycle R&D Group, Korea Atomic Energy Research Institute Permit Conditions • From the trial burns, each permit conditions ensure that the plant minimizes one or more of the following. • Emissions of hazardous (regulated) organic compounds. • POHCs via DRE • PICs via carbon monoxide or hydrocarbon, and APCE temperature. • Toxic and/or radioactive metal emissions. • Surrogate metals emission • Metals tier for environmental impact analysis • Hydrogen chloride (HCl) and chlorine (Cl2) emissions. • The likelihood of fugitive emissions and system upsets.

8. Nuclear Fuel Cycle R&D Group, Korea Atomic Energy Research Institute

9. Nuclear Fuel Cycle R&D Group, Korea Atomic Energy Research Institute Trial Burns for Organic Compound Destruction • The rate of organic destruction is governed by three Ts • Temperature, Time, Turbulence • Typical worst-case conditions for organic destruction are • minimum temperature • maximum carbon monoxide concentration • maximum gas velocity • maximum feed rate

10. Nuclear Fuel Cycle R&D Group, Korea Atomic Energy Research Institute Incinerability Considerations • POHC selection for representing the worst case condition for various organic compounds in waste feed. • Selection criteria : • Quantity in waste feed • Structural category (aliphatics, aromatics, chlorinated aromatics) • Toxicity • Incinerability ranking • “Don’t choose a POHC that’s a PIC”

11. Nuclear Fuel Cycle R&D Group, Korea Atomic Energy Research Institute Incinerability ranking • A concept that was developed for comparing the difficulty of destroying various organic compounds. • The ranking affords the plant owner/operator the flexibility to burn waste that are less difficult to destroy than those tested. • Incinerability • How readily it can be destroyed in a combustor.

12. POHCs Selection • Carbon tetrachloride (CCl4) and chlorobenzene (C6H5Cl) are used extensively as POHCs trial burns. • Not likely to upset the operation of the facility. • Feedable and meterable. • Not dangerous to handle. • Available in quantity at reasonable cost.

13. Nuclear Fuel Cycle R&D Group, Korea Atomic Energy Research Institute Setting Limits for Parameters That Affect Organic Compounds Destruction • Minimum Temperature • Lowest mean temperature at which successful test (minimum of three runs) occurred. • Rolling average minimum temperature limit. • Minimum temperatures of both PCC and SCC must be determined from the same test.

14. Nuclear Fuel Cycle R&D Group, Korea Atomic Energy Research Institute Setting Limits for Parameters That Affect Organic Compounds Destruction • Maximum Carbon Monoxide Concentration • To ensure proper mixing of oxygen and organic constituents in the PCC, and thus to inhibit the formation of PICs. • The max. limit of carbon monoxide in Korea, is set on the basis of regulation rather than the trial burn (either instantaneous or hourly rolling average).

15. Nuclear Fuel Cycle R&D Group, Korea Atomic Energy Research Institute Setting Limits for Parameters That Affect Organic Compounds Destruction • Upper Limits on Gas Flow Rate • To control the gas residence time in each combustion chamber. • To control the gas throughput of the entire system so that back pressure is minimized at joints and seals. • To control the gas flow through the APCE so that the equipment is not overloaded. • The limit must be set from the permit condition on minimum temperature.

16. Nuclear Fuel Cycle R&D Group, Korea Atomic Energy Research Institute Recommendations for Minimum Temperature Waste Feed Cutoff • Maximum Waste Feed Rate • to prevent overload of PCC and SCC • to keep the residence time above the minimum level required to destroy the POHCs • to accommodate other parameters, such as chlorine and ash/metal feed rate

17. Nuclear Fuel Cycle R&D Group, Korea Atomic Energy Research Institute Setting Limits for Parameters That Affect Organic Compounds Destruction • Other parameters • Waste characteristics • volatile content of the waste • heating value of the waste • APCE operating parameters • APCE inlet temperature, etc.

18. Nuclear Fuel Cycle R&D Group, Korea Atomic Energy Research Institute Trial Burns for Metals Emission Control • The best 3T conditions for organic destruction are the worst conditions for metals and particulate emission. • Particulate entrainment (Turbulence) • Abrasion (Turbulence) • Volatilization/Condensation (Temperature, Time)

19. Nuclear Fuel Cycle R&D Group, Korea Atomic Energy Research Institute General Considerations in Planning Trial Burns for Metals Emission Control • The plant’s operation under normal condition • The plant’s operation under worst-case condition • The appropriate tier for metals for environmental impact analysis • The form of the metal in different stages and its leachability

20. Nuclear Fuel Cycle R&D Group, Korea Atomic Energy Research Institute Surrogate Metal • Surrogate metals are metals used as conservative indicators for emissions for other metals. • Using surrogate metals is a sensible approach for three reasons. • Decreased cost of trial burns. • Decreased environmental impact during trial burns. • Increased development of data.

21. Nuclear Fuel Cycle R&D Group, Korea Atomic Energy Research Institute Arguments against Using Surrogate Metals • Insufficient data exist to justify a ranking scheme for metals based on theoretical volatility. • Some metals are not consistently volatile and their volatility depends on other variables, such as the presence of other metals. • Various kinetic limitations on metals volatility.

22. Nuclear Fuel Cycle R&D Group, Korea Atomic Energy Research Institute Metals Tiers Tier 1: Feed Assume all metal escape No TB required; Conservative general dispersion table Tier 3: Dispersion TB required; Site-specific dispersion model Thermal System Off-Gas System Feed Dispersion in Atmosphere Adjusted Tier 1: Feed & Dispersion Assume all metal escape Site-specific dispersion model Tier 2: Emissions TB required; Conservative general dispersion table

23. Nuclear Fuel Cycle R&D Group, Korea Atomic Energy Research Institute Upward Extrapolation Actual Metals Emission Curve Emissions Limit 2 4 Stack Emission Rate Trial burn point 3 5 1 Metals Feed Rate • Theoretical conservative • Recommended

24. Extrapolation Trial burn point 1 Emissions Limit 4 Stack Gas Emission Rate 2 3 5 Metals Feed Rate • Not theoretically conservative • Not recommended Nuclear Fuel Cycle R&D Group, Korea Atomic Energy Research Institute Downward Extrapolation of Emission Rate

25. Recommendations • Current Status in Korea • Little permitting load map • Little technical transfer to public • Little fundamental research on Dioxin/Furan formation/destruction • Little fundamental research on metals behavior/control • Typical Incinerator Emissions (attached) • Technology Deficiency Prioritized List (attached)