Water Droplet Carryover ˃ Failure to remove water droplets after particle capture is the most significant impact on performance. ˃ Water droplets contain both suspended and dissolved solids which evaporate before the Method 5 filter (248 +/- 25 0 F) and particles are measured as filterable particulate. ˃ Impact of droplets can be determined by comparing the measured (lb./ dry gas) to theoretical at the gas temperature and absolute pressure.
Water Droplet Carryover ˃ The lower the allowed mass emission rate, the more significant droplet carry over becomes. ˃ A completely dry demister outlet cannot be achieved without fouling and eventual failure. ˃ Build-up of dissolved solids in recirculated water can result in visible plumes (NaCl, KCl, NH 4 Cl 2 solids) which form submicron aerosols when droplets evaporate in the atmosphere.
System Hydraulic Balance Methodology ˃ Inlet gas moisture (vapor) phase ˃ Evaporation in quench section to achieve saturation (a function of absolute pressure and temperature), an adiabatic process ˃ Condensation of water vapor due to increase in under pressure (function of absolute pressure) ˃ Enthalpy of make-up water is usually small ˃ Enthalpy of blow-down water streams can be insignificant ˃ Net gain or loss of water vapor at each point in the process impacts performance ˃ Water of hydration and free water in sludge's must be included in the balance
Heat Balance ˃ Inlet enthalpy of dry gases, water vapor, solids must estimated ˃ Enthalpy of gases and solids at each intermediate point in the gas stream must be calculated with changes in pressure ˃ Enthalpy of make-up streams should be included ˃ Enthalpy of blow-down streams (liquid and solids) should be included
Heat Balance (cont.) ˃ Final stack temperature calculated and gas stream moisture content ˃ Inlet/outlet enthalpy must balance to estimate final gas temperature and moisture content ˃ Iterative process using goal seek or solver in excel between mass and heat
Semi-Dry Gas Scrubbing Ronald Hawks, Process Manager/ Senior Managing Consultant
Components of a Dry Injection System
Components of a Spray Dryer Absorber System
Basic Principles ˃ Slurry is produced and sprayed into hot gas stream ˃ Acid gases are absorbed into water droplets as it evaporates ˃ An aqueous solution is produced
Basic Principles (cont..) ˃ Acid in solution reacts with base in solution in suspension forming salt ˃ Dry salt with unreacted sorbent captured on a filter surface
Process Design ˃ Determine source inlet gas characteristics (temperature, gas volume, acid gas concentration, etc.) ˃ Determine the required acid removal (%) ˃ Estimate the required sorbent injection rate to achieve the acid gas removal (i.e. lb./lb. acid) on Ca/S molar ratio ˃ Calculate the quenched gas temperature and moisture content
Process Design (cont..) ˃ Calculate the relative humidity of gases passing through the filter ˃ Calculate the concentration of un-reacted sorbent in dust
Operational Issues ˃ The approach of the quenched gas to moisture saturation (dew point) increases acid gas removal (i.e., 15 0 F above saturation optimal) ˃ Condensation of water on interior surfaces of ducts and filter walls results in fouling and corrosion unless well insulated
Operational Issues (cont.) ˃ Variation in flue gas temperature due to boiler load, excess air and swing load demand, can result in poor performance and/or fabric fouling ˃ Design must include review of past and expected boiler operation and gas stream conditions
Overall System SO 2 Removal Efficiency
T HE A DVANTAGES OF F LAMELESS T HERMAL O XIDATION Michael Foggia Business Development – Marketing Manager Process Combustion Corporation mfoggia@pcc-group.com 503-799-2372 27 Annual Business and Industries Sustainability and EH&S Symposium March 27 - 28, 2018 Duke Energy Center – Cincinnati, Ohio 39
Process Combustion Corporation Process Combustion Corporation Flameless Thermal Oxidation Flameless Thermal Oxidation 40
What is Flameless Oxidation? Flameless oxidation is a thermal treatment that premixes waste gas, ambient air, and auxiliary fuel prior to passing the gaseous mixture through a preheated inert ceramic media bed . Through the transfer of heat from the media to the gaseous mixture the organic compounds in the gas are oxidized to innocuous byproducts, i.e., carbon dioxide (CO 2 ) and water vapor (H 2 O) while also releasing heat into the ceramic media bed. The reason why a flame is not generated in the media bed is because the gas mixture is kept below the lower flammability limit based on the percentages of each organic species present. Waste gas streams experience multiple seconds of residence time at high temperatures leading to measured destruction removal efficiencies that exceed 99.9999% . Premixing all of the gases prior to treatment eliminates localized high temperatures which leads to thermal NOx as low as 1 ppmv. 41
FLAMELESS THERMAL OXIDIZER (FTO) Functional Criteria • A refractory lined vessel filled with ceramic media • Bed is preheated to initiate oxidation reactions • Premix Waste Gas, Ambient Air, and Natural Gas - “Feed Forward Design” • Gas mixture below flammable range (Below LEL) • Oxidizing; Not Combusting • Maximum Temperature 1800-1900°F 42
FLAMELESS THERMAL OXIDIZER (FTO) Design Benefits: High DRE……… 99.9999% Low Thermal NOx….. < 1 ppmv Low Temperatures Throughout Easy Control: Constant Volume Flow & Enthalpy (Heat) 43
How do we achieve a DRE of 99.9999%? 3 T’s of Destruction: Time, Turbulence (mixing), Temperature • Premixing of waste gas, natural gas, and oxidizing air Residence Time (s) • Bed operating temperature ~1800 ° F (1500 kJ/Nm³) • Excess oxygen level of ~12% • Multiple seconds of residence time at high temperatures 44
How do we achieve NOX emissions < 1 ppm? Yakov Zel’dovich Determined the correlation between temperature and NOx formation in a combustion system. Temperatures >2300F cause an exponential growth rate in NOx generation. 1800 o F 45
Comparative NOx Performance The PCC FTO achieves 50x less NOx than the Industry Standard Burner! 46
Competing Control Technologies NOx v.s. DRE Indication of an underserved market High FTO: 99.9999% DRE Thermal Oxidizer <1ppm NOx RTO High Low Flare Bio‐Oxidation Low DRE NOx 47
Where is the FTO Technology best used? Regenerative Catalytic Thermal Carbon Project Parameter Thermal Oxidizer Oxidizer Adsorption Bio Oxidizer Oxidizer (RTO) (CO) (TO) Technology High Concentration X X Low Concentration X X X X X X Halogenated Service – X X X Cl, Fl, Br Sulfur, Mercaptans, X X X X thiols, etc. DRE 99.99% + X X Continuous Process X X Batch Process X X NOx < 1 ppmv X X X 48
Proactive Control to Manage Change Vent Source 1 AIT FIT AE FE LEL; BTU Vent Source 2 TO FTO Vent Source 3 Vent Source 4 FTO is a Smart “Feed-Forward” Reactor • No More High/Low Temp Trips…. • No More Nuisance Shutdowns…. Great for Sold Out Products! Maximum Utilization of Production Time! 49
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FTO APPLICATION FITS Best fits are high end customers requiring very low NOx, very high DRE, and high reliability such as pharmaceutical & specialty chemical companies. Also best with clean waste streams with reasonable organic heating value. 51
Example FTO Installation System Burner (Start-up Only) Dip Tube 52
Chemical Reactions In Air O3 O2 (Ozone) Smog HNO3 Accumulation NO2 Acid Rain VOC’s N2O NO Combustion Activities 53
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Performance Beyond Compliance In a typical ozone Nonattainment New Source Review project, one requirement is to offset the project emissions of the ozone precursor (NOx or VOCs) with emission reduction credits (ERCs) obtained from a source within the nonattainment area. ERCs in the Gulf Coast can cost up to $400,000 per ton! Lowering stationary source emissions through the use of a Flameless Oxidizer can prevent having to purchase ERCs and may in fact generate ERCs that can be used to expand a plant or sold. FTO Permit Benefits: 1) Generate emission credits that can be banked or sold 2) Allow for plant expansions without modifying an existing air permit 55
PCC FTO Your Environmental Competitive Advantage Flameless Oxidation Values Feature Benefit Low NOX <1 ppmv NOx Low Temperature Premixed Oxidation High DRE 99.9999% DRE Premixed Oxidation; 3-4 seconds RT; Stable/Resilient Oxidation Environment; Feed Up-Time forward control; No Moving Parts; No thermal > 99% Uptime cycling of media bed (Long ceramic Life) Eliminate requirement for CEMS (High Easy Permitting Less time to permit Performance Oxidizer Reactor) Lower Permitting Costs, Emission Credits, Added Lower emissions; Emission Trading opportunity; ROI Reliability (More Production) Ease of site expansion Operational Flexibility Multiple control set points; 100% Waste gas “Ready-Idle” mode to limit fuel turndown; Accept varying waste compositions use & Stable Operation 56
T HANK Y OU 57
PCC BioOxidation Outline • BioOx Basics • Technology Development: BioOxidation vs. Traditional Biofiltration • Technology Comparison: BioOxidation vs. RTO • Applications 1. Wood Products Process 2. Asphalt Process • PCC BioOx Research and Development BioOxidation System Asan, South Korea
Why add BioOxidation? PCC wanted the ability to offer a “non‐thermal” solution where appropriate Better alternative to RTO’s in many applications (high flow, low concentration) Dual‐BioPhase Technology is new and innovative “Green” Technology Does not consume Natural Gas Does not generate NO x SO x CO Produces ~90% less CO 2 vs. Thermal Oxidation Operates at ambient temperature and low pressure
BioOx Basics Biological Oxidation (Biofiltration): • Process whereby contaminants transfer from air phase to biofilm. • Biodegraded by microorganisms. Pollutant + Bacteria + Oxygen + Nutrients CO 2 + H 2 O + More Bacteria • Biofilm is the primary element of the Bio‐Oxidizer involved in the destruction of the contaminants. • As Biofilm continually grows, it must slough off to maintain a healthy microbial colony.
Microbes a.k.a Bacteria or Bugs “ Microorganism” refers to a wide variety of single cell, live bacteria. FREEZE DRIED MICROORGANISMS NUTRIENT ADDITIVE Given sufficient time and quantities, bacteria can biodegrade nearly anything.
Microbes a.k.a Bacteria or Bugs FAQ>>> “What happens if the Bugs get out of the bio‐oxidizer unit?” Nothing……………. Bacteria is Everywhere in Nature • We utilize naturally occurring bacteria. • We create an environment which allows them to work in an enhanced and significantly more efficient manner than typically found in nature.
Biological Media Development X X X X Organic Dual-BioPhase ™ X Evaluation Category Media Synthetic Media Microorganisms and Nutrients are Restrained within Media Yes No Media Replacement is Required to Replenish Nutrients Yes No Media needs Continually Fluffed to Obtain Porosity Yes No Biomass Growth Causes Media Settling Yes No Continually Increasing ΔP Yes No Maintaining Optimal Water Content is Crucial Yes No Media Height Limited to Maintaining Proper Moisture Content Yes No Capacity for Contaminants - ppmv <50 <5,000 Limited Capacity to Neutralize Acids Yes No
Biofilm – Biomass - Slough off
Technology Development: BioOxidation vs. Biofilter Compost Filter Bed (about 1 meter in depth) Open Biofilter System Humidifier Foul Air Limited Bed Depth Media Replacement Necessary Poor Removal Efficiency due OLD Gravel to Dry-out and Channeling Ground TECH
Early Bio‐Filter Designs Bed Compaction Channeling Channeling
Old Style Biofilter Overall footprint 100’ x 170’ X Removing Failed Media Old Media
PCC BioOxidizer System Nutrient Enriched Feed Less Soluble Pollutants are Treated in the Gas Phase Mass Transfer to Liquid Maximized BIO Biological Oxidation in 1) Liquid and 2) Gas Phase Water Soluble Pollutants are Treated in the Liquid Phase ABSORBER Footprint Minimized Contaminant Ambient BIO Air Recirculating Loop to Aeration Mixer PCC NEW TECH
BioOxidation vs. Biofilter Bio-Oxidizer Footprint Traditional Biofilter Technology
BioOxidation System Advantages Category Typical Biofilter Dual-BioPhase ™ Bio-Oxidizer Footprint Very Large ~6-8 Times Smaller Media Replacement Periodically possible Not Required Fouling/Plugging Potential Plugging Anti Fouling Design Nutrients Manual Addition, bulk Metered delivery system Water Blow Down Potential Black Water Treated Water Start Up Inoculation Waste Water Bacteria Selected per Contaminant Start Up Food Source Molasses Contaminant – Waste Stream Pressure Drop Potential Gradual Increase Stable VOC Removal Limited Potential >95% DRE
Technology Comparison: PCC BioOx vs. RTO
Technology Comparison: PCC BioOx vs. RTO Category RTO Dual-BioPhase ™ Bio-Oxidizer Natural Gas Usage Yes $$$ None required Operating Temp 1500F – 1600F Ambient 60F – 150F (wet bulb) Fire Hazard Potential No – Humid, Wet System Maintenance Valve wear & Tear No Major Moving Parts Fouling/Plugging Potential Plugging Anti Fouling Design Media Change Out Probable No CO, NOx Emission Yes No SOx Emission Potential No CO 2 Emission Yes ~90% Less Post Treatment Potential No
PCC BioOx and RTO Operating Cost Comparison Engineered Wood Products Application: Flow rate: 215,000 acfm; Loading: 165 lb/hr VOC (75 kg/hr) (365,300 m 3 /hr) Parameter BIO RTO 1 Electric Usage (kW) 459.0 352.8 BURNING YOUR PROFITS ? $241,258 $185,411 Electric Cost 2 (¥1.6 MM) (¥1.2 MM) $20,000 Nutrient Cost - (¥130,000) $756,232 Natural Gas Cost 3 - (¥5.0 MM) $261,258 $941,643 Min. Total Operating Cost 4 (¥1.74 MM) (¥6.3 MM) Maintenance Cost Less More CO 2 Generation (tpy) 690 19,386 1 RTO DRE = 98%; HRE = 92.5% 2 Electric price taken to be $0.06/kWh, and 8760 hr/year 3 Natural gas price taken to be $3/MM BTU 4 Does not consider maintenance or media change out costs 96.4 % Less CO 2 emitted $680,000 ( ¥ 4.5 MM) Less Operating Cost
WOOD PRODUCTS First thermophilic gas‐phase BioOxidizer in the world PB PW OSB PB = Particle Board PW = Plywood OSB = Oriented Strand Board MDF MDF = Medium Density Fiber
Width: Height: 33 ft 90 ft 10 m 27 m 330,000 acfm 140 °F
Mist Eliminator Bed
Gas Phase Biological Media Bed
Absorption Media Bed
Liquid Irrigation (6,500 gpm; 1,476 m 3 /hr)
Liquid BioOxidation Section
Aerator Manifold and Liquid BioMedia
Biofilm
Asphalt Plant Emission Control DRE Hydrogen Sulfide 98.7% Methyl Mercaptan 98.7% Acetaldehyde 71.7% Propionaldehyde 19.4% Isovaleraldehyde 40.0%
Diameter: Height: 12ft 52ft 3.7m 15.7m
FULL SCALE TESTING
ISOLATION STACK VALVES WALL CONDENSER HEATED PROBE COOLING ADSORBEN DRY GAS WATER LOOP T TUBE CONDENSER METER VACUUM PUMP Send impinger water (methanol and formaldehyde capture) and carbon tube ROTAMETER (pinene capture) to lab for quantitative analysis GAS MIDGET IMPINGER DRYER (WITH DISTILLED WATER)
Glassware box – condensers, liquid impinger, and carbon adsorbent tube Console – vacuum pump, Heated flow control, and gas meter probe Ice bucket for condenser cooling loop Sampling train is connected to console with heated umbilical cord
EWP Outlet Gas Sampling Data – March 13, 2017 FID 1 FID 2 FID 3 50 50 50 40 40 40 30 30 30 AVG 38.75 AVG 39.18 AVG 45.55 SD 3.52 20 20 SD 1.10 SD 0.74 20 RSD 9.08% RSD 2.82% RSD 1.64% 10 10 10 Time 31 min Time 28 min Time 28 min 0 0 0 FID 4 FID 5 FID 6 50 50 50 40 40 40 30 30 30 AVG 42.34 AVG 47.05 AVG 47.86 SD 0.77 SD 0.86 20 SD 0.78 20 20 RSD 1.82% RSD 1.82% RSD 1.63% 10 10 10 Time 28 min Time 14 min Time 28 min 0 0 0 FID 7 FID 8 FID 9 50 50 50 40 40 40 30 30 30 AVG 32.70 AVG 30.81 AVG 34.47 20 SD 0.89 20 SD 0.78 20 SD 0.67 RSD 2.72% RSD 2.53% RSD 1.94% 10 10 10 Time 27 min Time 26 min Time 28 min 0 0 0
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