Fuel Quality and MATS for CoalFired Plants: The Ripple Effect Connie Senior & Greg Filippelli EUEC, February 3-5, 2014 © 2014 ADA-ES, Inc. ADA-ES Emission Control Products © 2014 ADA-ES, Inc. Mercury & Air Toxics Compliance: Almost Here Mercury Study Report to Congress 1997 Clean Air Mercury Rule (later vacated) Various state rules for EGUs 2005 2012 2013 2015 © 2014 ADA-ES, Inc. ► Mercury & Air Toxics Standards for EGUs ICI Boiler MACT, CISWI, Portland Cement Compliance Begins …CAIR/CSAPR, Regional Haze Rule, too The Ripple Effect ► ► You’ve put in a DSI system for MATS compliance How are your future fuel choices going to affect performance and cost of operation? © 2014 ADA-ES, Inc. Ground Rules ► ► WHY? Dry Sorbent Injection (DSI) means different things at different plants ► So let’s make sure we know the ground rules ► ► ► © 2014 ADA-ES, Inc. HCl control (low-sulfur coal) SO2 control (low-sulfur coal) SO3 control to improve ACI system performance (highsulfur coal) Blue plume control during the heating season and SCR use Ground Rules ► ► Dry Sorbent Injection (DSI) means different things at different plants So let’s make sure we know the ground rules HOW? SO3 Hydrated lime Ca(OH)2 Sodium bisulfite (SBS) Limestone Mg(OH)2 MgO Trona – sodium sesquicarbonate Sodium bicarbonate (SBC) SO2 © 2014 ADA-ES, Inc. HCl Coal Quality: Sulfur % S (dry) 0.4 - 1.0 1.0 - 1.6 1.6 - 2.5 2.5 - 3.4 3.4 - 4.7 Source: Quick, USGS ICR2 (1999) data © 2014 ADA-ES, Inc. Coal Quality: Chlorine Cl (mg/kg, dry) < 100 100 - 250 250 - 500 500 - 1000 1000 - 2000 2000 - 4446 Source: Quick, USGS ICR2 (1999) data © 2014 ADA-ES, Inc. Know Your Sorbent ► How will your sorbent respond to changes in coal composition? Hydrated lime ► HCl SO3 % Control ► ► ► SO2 Used for HCl and SO3 control Injected at relatively low temperatures SO2 capture typically <20% Changes in coal sulfur have relatively: − − Temperature Source: L’Hoist, 2011 © 2014 ADA-ES, Inc. Minor impact on HCl control Proportionate impact on SO3 control Know your sorbent ► How will your sorbent respond to changes in coal composition? Sodium Sorbents ► ► ► Effective for HCl and SO3 control (varying utilization) Injected at relatively high (≤1500oF) temperatures Changes in coal sulfur may have: – – – Source: Solvay, 2012 © 2014 ADA-ES, Inc. Minor impact on HCl control Proportionate impact on SO3 control Measurable impact on sorbent use rate Ripples ► Will changing DSI rates affect anything else? ► ESP performance ► Bag cleaning rates ► © 2014 ADA-ES, Inc. Hg control with activated carbon injection (ACI) Ripples ► Will changing DSI rates affect anything else, like PM emissions? 1.E+12 90% EBit/ 5% Ca(OH)2/ 5% CaSO4 ► Bituminous Coal − Resistivity, ohm‐cm 1.E+11 − 1.E+10 90% EBit/ 10% Ca(OH)2 1.E+09 − Eastern Bituminous 1.E+08 100 Source: Mastropietro, 2010 © 2014 ADA-ES, Inc. 300 500 Temperature, F 1000 Hydrated lime addition can increase fly ash resistivity (lab data) Reduction in SO3 in flue gas also increases resistivity Depending on the size and condition of the ESP, use caution in increasing hydrated lime rates in response to higher sulfur coal Ripples ► Will changing DSI rates affect anything else, like PM emissions? 1.E+13 ► Subbituminous Coal − Resistivity, ohm‐cm 1.E+12 1.E+11 90% PRB/ 5% Ca(OH)2/ 5% CaSO4 1.E+10 90% PRB/ 10% Ca(OH)2 − PRB − 1.E+09 100 Source: Mastropietro, 2010 © 2014 ADA-ES, Inc. 300 500 Temperature, F 1000 Hydrated lime might increase resistivity (lab data) Native resistivity is already so high that that flue gas conditioning system might already be in place, depending on size and condition of ESP More flue gas conditioning agent may be required Ripples ► Will changing DSI rates affect anything else, like PM emissions? 1.E+13 ► PRB Subbituminous Coal − Resistivity, ohm‐cm 1.E+12 − 1.E+11 1.E+10 90% PRB/ 10% trona 1.E+09 100 Source: Mastropietro, 2010 © 2014 ADA-ES, Inc. 500 300 Temperature, F 1000 Sodium sorbents tend to lower resistivity of fly ash (lab data) Sodium-based DSI could improve ESP performance, depending on size and condition of ESP Ripples ► Will changing rates affect anything else, like the ACI system performance? MRC Results: 10 lb/MMacf, injection upstream of APH APH Inlet: 627 F; APH outlet: 300 F (assume 1 ppm baseline SO3) ► Hg removal across ESP 100% 80% When DSI is used for SO2 control, two potential effects on ACI for Hg control: − 60% 40% 20% Brominated PAC #1 Brominated PAC #2 0% − 0 10 Source: Pollack, Air Quality VII, 2009 © 2014 ADA-ES, Inc. 20 ppm SO3 30 High temperature (pre-APH) injection could remove halogens in flue gas before they have a chance to react with Hg: reduced effectiveness of nonbrominated PAC Increasing DSI sorbent also decreases SO3 concentration: increased effectiveness of PAC Ripples ► Will changing rates affect anything else, like the ACI system performance? 2.0 100% PRB (trona, 0.76 NSR) 1.6 Hg Emission, lb/TBtu ► 100% PRB (no DSI) 1.8 100% PRB (sodium bicarbonate, 0.85 NSR) ► 1.4 1.2 1.0 ► 0.8 0.6 0.4 0.2 0.0 0.0 0.5 1.0 1.5 2.0 PAC Injection, lb/MMacf Source: Rogers et. al, 2013 EUEC © 2014 ADA-ES, Inc. 2.5 3.0 ► Example: Mercury stack emissions at St. Clair Unit 3 100% PRB, with additional halogen added to coal Non-brominated PAC injected downstream of air preheater and trona or sodium bicarbonate injected upstream of air preheater Production of NO2 reduced the effectiveness of PAC for Hg control Example ► Objective: HCl control, target to achieve <0.002 lb/MMBtu ► Air Pollution Control: Cold-side-ESP ► Trona injection for HCl control 100% PRB Coal sulfur content, wt% 0.28 Coal chlorine content, wt% 0.01 Higher Heating Value, Btu/lb 8,960 SO2 at Injection Location, lb/MMBtu 0.63 Milled Trona, Expected Injection Rate, lb/hr 2,085 © 2014 ADA-ES, Inc. Example ► Objective: HCl control, target to achieve <0.002 lb/MMBtu ► Air Pollution Control: Cold-side-ESP ► Trona injection for HCl control 100% PRB 85% PRB-15% Bituminous Coal sulfur content, wt% 0.28 0.75 Coal chlorine content, wt% 0.01 0.02 Higher Heating Value, Btu/lb 8,960 9,952 SO2 at Injection Location, lb/MMBtu 0.63 1.51 Milled Trona, Expected Injection Rate, lb/hr 2,085 7,900 © 2014 ADA-ES, Inc. Put A Plan Together 1. Compile composition data for coals to be considered 2. Compile data on APCD operating constraints 3. 4. 5. 6. Compile data on unit performance with respect to fuel options Process coal data to assess corresponding expected sorbent consumption (alkaline and carbon sorbents) Assess predicted sorbent loading impacts on APCD and emissions Model optimized fuel composition ranges to meet operational and compliance objectives © 2014 ADA-ES, Inc. Questions? ► If you have questions, please contact: − [email protected] − [email protected] © 2014 ADA-ES, Inc.