TRIAL BURN TECHNOLOGY FOR WASTE THERMAL PLANT

Transcription

1 유동층공학환경응용기술연구회 TRIAL BURN TECHNOLOGY FOR WASTE THERMAL PLANT 한국원자력연구소 / 핵화공연구팀 양희철

2 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

4 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 Integrated Waste Thermal Treatment System Waste Sorting Homogenizing Flue gas Incinerator Bottom ash Flue gas Vitrifying Melter Air Pollution Control System Fly ash To exhaust stack Spent scrubber liquor to liquid treatment Slag forming additives Slag tap Molten metal tap

6 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 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 (Cl 2 ) emissions. The likelihood of fugitive emissions and system upsets.

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9 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 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 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 (CCl 4 ) and chlorobenzene (C 6 H 5 Cl) 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 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 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 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 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 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 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 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 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 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 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 Feed Thermal System Off-Gas System 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 Upward Extrapolation Emissions Limit 2 4 Actual Metals Emission Curve Trial burn point Metals Feed Rate Theoretical conservative Recommended

24 Downward Extrapolation of Emission Rate Emissions Limit Extrapolation Trial burn point Metals Feed Rate Not theoretically conservative Not recommended

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)