Mitsubishi Hitachi Power Systems America Coal to Gas Conversions Joe Brown AMS Product Manager 9/28/15 MITSUBISHI HITACHI POWER SYSTEMS AMERICAS, INC.
Units Faced with Environmental Challenges Shut Down the Unit Install Lowest New Capital Combined Cost Cycle Option Eliminate all potential source of generation and potential capacity Re-power Minimize revenues to emmisions and Combined with must incur Cycle an efficient generation source burning cheap gas de-commissioning cost (Replacement Same generation benefits Very high capital cost as a Combined cost possibility) Cycle but re-using the Steam Turbine if Install possible Capital Air Quality ~ Control $1,250/kw++ Systems High Installing Capital the cost latest ~ AQCS $1,000/kw++ allows unit to remain operational with most Install Additives (DSI/ACI/ SNCR) if Fuel has low enough Sulfur and fuel flexibility Nitrogen to comply High Capital Costs: FF ~ $40/kw, DryFGD ~ $125/kw, SCR ~ $160/kw, Convert Low Upfront with increased to Natural cost while maintaining coal capability: ACI ~ $5/kw, SNCR ~ equipment Gas to maintain and manpower A $14/kw, Low cost DSI option ~ $5/kw ($26 ~ $65/kw) that eliminates most all Hg, Particulate Become and Unit Sulfur has Dual no emissions Fuel fuel flexibility Fired while (Gas & deactivating now and has Coal Higher with coal Additives) operational equipment cost and associated with Boiler, manpower Air Unit Heater can switch and to maintain Ductwork to lowest it Impacts cost fuel (Corrosion, option instantaneously, Ammonia slip, and material can meet Gas drop-out future Supply regulations concerns, line has etc.) to be available to be cost effective and efficiency goes Paying down for two slightly separate systems upfront 1
Units Faced with Environmental Challenges Shut Down the Unit Lowest Capital Cost Option Eliminate all potential source of generation and potential capacity revenues and must incur de-commissioning cost (Replacement generation cost a possibility) Install New Combined Cycle Minimize emmisions with an efficient generation source burning cheap gas Very high capital cost ~ $1,250/kw++ Re-power to Combined Cycle Same benefits as Combined Cycle but re-using the Steam Turbine if possible High Capital cost ~ $1,000/kw++ Install Capital Air Quality Control Systems Installing the latest AQCS allows unit to remain operational with most fuel flexibility High Capital Costs: FF ~ $40/kw, DryFGD ~ $125/kw, SCR ~ $160/kw, with increased equipment to maintain and manpower Install Additives (DSI/ACI/ SNCR) if Fuel has low enough Sulfur and Nitrogen to comply Low Upfront cost while maintaining coal capability: ACI ~ $5/kw, SNCR ~ $14/kw, DSI ~ $5/kw Unit has no fuel flexibility & now has Higher operational cost with Boiler, Air Heater and Ductwork Impacts (Corrosion, Ammonia slip, material drop-out concerns, etc.) Convert to Natural Gas A Low cost option ($26 ~ $65/kw) that eliminates most all Hg, Particulate and Sulfur emissions while deactivating coal equipment and associated manpower to maintain it Gas Supply line has to be available to be cost effective and efficiency goes down slightly Become Dual Fuel Fired (Gas and Coal with Additives) Unit can switch to lowest cost fuel option instantaneously, and can meet future regulations Paying for two separate systems upfront Financial Information based on OEM Awards and Industry Data 2
Natural Gas Prices (EIA) Year Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec 2002 3.1 2.86 3.37 3.8 3.78 3.61 3.49 3.42 3.71 4.19 4.35 4.72 2003 5.33 6.47 7.05 5.38 5.7 6.08 5.45 5.23 5.12 4.98 4.85 5.69 2004 6.37 5.76 5.5 5.74 6.3 6.52 6.24 5.97 5.39 6.05 6.71 6.88 2005 6.72 6.42 6.84 7.27 6.83 7.08 7.57 8.67 10.99 11.84 9.87 11.26 2006 9.15 8 7.36 7.32 6.89 6.69 6.69 7.56 6.27 5.76 7.48 7.57 2007 7.08 8.18 7.64 7.77 7.96 7.8 7.03 6.83 6.33 7 7.28 7.93 2008 8.52 8.87 9.53 10.19 10.97 12.41 11.71 8.97 7.81 6.74 6.64 6.9 2009 6.62 5.62 4.92 4.7 4.7 4.62 4.47 4.3 4.02 5.04 5.06 6.24 2010 6.98 6.27 5.47 4.91 4.96 5.31 5.34 5.06 4.61 4.45 4.55 5.68 2011 5.66 5.29 4.84 5.03 5.04 5.2 5.13 4.85 4.71 4.49 4.26 4.18 2012 3.82 3.46 3.09 2.81 3.05 3.21 3.54 3.61 3.54 4 4.43 4.35 2013 4.56 4.59 4.5 4.84 4.79 4.56 4.34 4.03 4.19 4.26 4.36 5.11 2014 7.47 7.79 6.28 5.25 5.08 4.98 4.58 4.25 4.34 4.23 4.68 4.5 2015 4.29 4.99 3.71 3.23 3.28 3.24 3
Natural Gas Switching - Benefits Air Quality Control System Retrofits Avoided (FGD, ESP, PAC, DSI, PJFF, SCR, etc.) Reduced O&M Costs Coal Unloading, Storage & Conveying Pulverizer motors Primary Air Fans Ash Conveying, Sluicing & Disposal Sootblowing Equipment, Piping & Controls Dust Collection & Suppression Reduce manpower associated with above No Boiler Erosion/Corrosion CO2 Reduction 40% for Boiler Retrofit 4
Gas Conversion Technologies Design Features Three Main Components of Gas Conversion: Natural Gas Low NOx Burner modification of existing coal burner Natural Gas Piping and Control Valve Skids Flue Gas Recirculation (If Needed) to raise steam temperature and lower NOx emissions Can cost effectively maintain capacity with minimal modification 5
Capacity and Main Steam Temperature Issues Boilers are sized for specific Fuels: A Coal Boiler is much larger in size than a Gas Boiler of the same MW Capacity. When a Coal Boiler is converted to Gas, it is more difficult to get the reach Main Steam Temperature and Full Load Capacity. To maintain Boiler Capacity Firing Rate must be increased To Maintain Steam Temperature there are several method (if needed): Increasing Excess Air Increasing SH/RH Surface Adding Gas Recirculation for Steam Temperature Control 6
CFD Model Simulation Predicted performances lead to technical solutions - Temp. - CO - NOx - Heat Flux Simulation time Input : 1 hour Calc. : 1 hour - VOC emission - Burner performance - Furnace exit gas temperature Boiler Modelling is required to determine the Conversion US. : 2003/0182338 impacts 7
Retrofit Gas Canes to LNB Coal Burners Maintaining Coal Firing Capability Customer 1 Customer 2 Customer 3 Boilers 2 1 1 MW 131 225 355 Main Steam Flow (x10 3 lb/hr) Reheat Steam Flow (x10 3 lb/hr) 1200 1580 2500 No 1324 2164 Airheater Arrangement Coal Flow (x10 3 lb/hr) Coal Quality (HHV Btu/lb) Total Heat Input (x10 6 Btu/hr) Bi-Sector (Hot PA Fan) Bi-Sector (Hot PA Fan) Bi-Sector (Hot PA Fan) 105.8 158 257.7 13,141 13,054 12,500 1390.3 2062.5 3221.2 Burner Quantity 8 Front 12 Front 8 Front 8 Rear Burner Heat Input 173.8 171.9 201.3 (x10 6 Btu/hr) Efficiency (%) 86.4 88.10 89.38 8
Natural Gas Performance (Estimated) Maintaining Coal Firing Capability Customer 1 Customer 2 Customer 3 Boilers 2 1 1 MW 131 225 355 Main Steam Flow (x10 3 lb/hr) Reheat Steam Flow (x10 3 lb/hr) 1200 1580 2500 No 1324 2164 Total Heat Input (x10 6 Btu/hr) 1390.3 1443 2062.5 2169 3221.2 3396 Burner Quantity 8 Front 12 Front 8 Front 8 Rear Burner Heat Input 173.8 180.4 171.9 180.8 201.3 212.2 (x10 6 Btu/hr) Efficiency (%) 86.4 83.05 88.10 83.96 89.38 85.45 Increase Firing Rate to Maintain Full Load 9
Natural Gas Performance (Estimated) Maintaining Coal Firing Capability Customer 1 Customer 2 Customer 3 Boilers 2 1 1 MW 131 225 355 Main Steam Flow (x10 3 lb/hr) Reheat Steam Flow (x10 3 lb/hr) 1200 1580 2500 No 1324 2164 Total Heat Input (x10 6 Btu/hr) 1390.3 1443 2062.5 2169 3221.2 3396 Burner Quantity 8 Front 12 Front 8 Front 8 Rear Burner Heat Input 173.8 180.4 171.9 180.8 201.3 212.2 (x10 6 Btu/hr) Efficiency (%) 86.4 83.05 88.10 83.96 89.38 85.45 Boiler Efficiency typically drops between 3.5 5.5%, but parasitic load is also decreased from eliminating coal and its associated equipment 10
Gas Conversion NOx Generation NOx is formed when Nitrogen and Oxygen are both present in High Temperature Environments All Low NOx Strategies have to manipulate one or more of these three items in various ways for the most cost effective solution Because there is no Nitrogen in Natural Gas, Lower NOx Emissions can typically be achieved when converting from Coal to Gas. 11
Low NOx Strategies Reduce NOx/CO Emissions by: Utilizing the Latest Generation of Low NOx Burners Multi-Lance Gas Canes for each Coal Burner Adding Over-Fire Air Utilize BOOS (Burner out of service) Air Heater By-pass Utilizing SNCR Adding Gas Recirculation (FGR and IGR) for NOx Control 12
General Gas Burner Arrangement 13
Gas Burner Gas Canes 14
Coal Burner Retrofit with Full Load Gas Canes Lances through Windbox Ability to Maintain Coal Firing Capability 15
Coal Burner - Gas Retrofit Complexity Air Register Drive 16
Coal Burner Retrofit with Full Load Gas Canes Ring Header inside Windbox 17
Coal Burner Retrofit with Full Load Gas Canes 18
Burner Retrofit for T-fired Boilers New Gas Burners Existing Coal Burners Ability to Maintain Coal Firing Capability 19
Coal Burner Retrofit for T-fired Boilers New Gas Burners 20
Coal Burner Retrofit for T-fired Boilers T-Fired Burner Components (Rear) Windbox Cover Plate Auxiliary Air Compartment 21
Flue Gas Recirculation 22
Flue Gas Recirculation (100 MW example) 23
Flue Gas Recirculation (650 MW example) 24
Improved NOx with Increased FGR (Front Fired Example) Guaranteed NOx Rate 0.15 lb/mmbtu 0.08 lb/mmbtu FGR Required (100 MW Front Fired) FGR Required (150 MW Front Fired) 7% 16% 10% 22% Only a small amount of FGR is needed to achieve NOx compliance even on high NOx producing units 25
Additional Scope Recommendations Other Natural Gas System Requirements: Piping, Valves and Supports Trip Valve Station with Vent Piping Electrical and I&C Upgrade - Class 1, Division 2 (Typical) DCS Modifications 26
Natural Gas Piping Skids 27
Natural Gas Supply Valve Skid (Typical) 28
Natural Gas Distribution Burner Piping Linking burners by pairs or groups of four can drastically minimize cost 29
Typical Scope of Work Baseline Testing Boiler Thermal Modeling Scope of Work General Engineering Including: Drawings, P&IDs, Lists & Operation & Maintenance Manuals. CFD Model of Boiler Convection Pass Flue Gas Recirculation (FGR) Fan Foundation/Supports Natural Gas Burner Modifications: CFD Modeling of Combustion Air Duct, Windbox, Burners & Furnace Combustion Emissions Modeling Burner Elements, including internal gas ring and multiple gas spuds Igniters Double Block & Vent Valve Spools Pressure Regulating Valve (PRV) Skid With Vents Flow Control Valve (FCV) Skid With Vents Flexible Metal Hoses Flame Scanners 30
Typical Scope of Work Natural Gas Piping, Vent Piping, & Supports Scope of Work (Continued) Flue Gas Recirculation (FGR) Fans with Electric Motor, Turning Gear & Inlet Damper Control FGR Injection Mixing Devices FGR Differential Pressure Transmitters FGR Fan Inlet & Outlet Ducts with Hangers, Supports, and Expansion Joints FGR Duct Dampers & Actuators Burner Management & Combustion Control System Engineering & Modifications (including Hardware, Software and Implementation) Demolition of Existing Equipment Erection of New Equipment Secondary Steel & Erection Disabling of Coal Firing Equipment, Including Electrical Isolation Blanking Plates for the Primary Air and Tempering Air Duct Systems Technical Advisors for Construction & Commissioning Electrical Device Upgrades of Existing Equipment (Option) 31
Thank you very much MITSUBISHI HITACHI POWER SYSTEMS AMERICAS, INC. 32