Assessment of a Gas Quality Survey for Interchangeability
Assessment of a Gas Quality Survey for Interchangeability David Rue, William Liss Gas Technology Institute Algonquin Gas Pipeline Northeast Stakeholders Group June 15, 2006
Regional Natural Gas Composition Variations Exist Average Natural Gas Composition -- Twenty Six US Cities Source: Gas Technology Institute
Natural Gas and LNG Adjust gases are typical U. S. natural gases at city gates (GRI, 1992)
LNG Adjustment Methods In-tank Blending Mix low and high-Btu LNG. Requires inventory of low-Btu LNG Pipeline Blending Best when large volumes of low-Btu gas are available (Gulf Coast) Air Injection Up to 3. 8% air. Capital cost and oxygen content concerns Nitrogen injection Up to 2% nitrogen. Capital cost. Used by Distrigas and Cove Point. NGL stripping Capital cost. Need market for liquids Streaming Cargo ‘streamed’ through terminal to less-sensitive user (e. g. power)
Approaches to Interchangeability Prediction – Focus on Appliances • Single index (Wobbe, modified Wobbe, etc. ) – Incapable of describing all possible situations • Multiple indices (AGA, Weaver, etc. ) – Specific to burner type – Do not account for all fuel gases or emissions – Most common U. S. approach • Diagrams – Do not account for all fuel gases or emissions – Attempt to combine Wobbe index with composition parameters – Many variations and not universally accepted – Often used in Europe
Wobbe Number • Generally accepted as the best SINGLE index to determine interchangeability • For natural gas – alkanes – heat input through an orifice (Btu/h) at constant pressure is – proportional to heating value and – inversely proportional to the square root of specific gravity • Wobbe Number does not fully address interchangeability because changes in flame characteristics are not addressed W = HHV / (sp. gr. )0. 5
Interchangeability is Defined As The ability to substitute one gaseous fuel for another in a combustion application without materially changing operational safety or performance and without materially increasing air pollutant emissions Source – NGC+ Working Group on Interchangeability White Paper presented to FERC, Feb. 2005
Possible Combustion Problems With High BTU Gas Reported Problem From Flame lifting Excess air Backfiring Ow excess air or low velocity High CO Incomplete combustion High NOx Higher flame temperature Yellow tipping Flame lengthening from incomplete combustion Sooting Unburned hydrocarbon buildup
Interchangeability For Appliances The American Experience • AGA and USBM indices set limits for appliance fuel interchangeability • • AGA Yellow tipping Flashback Lifting USBM Yellow tipping Air Supply Flashback Heat release Lifting Incomplete combustion • ANSI codes are not specific for interchangeability • Interchangeability studies have been made by GTI, IGT, A. D. Little, So. Cal. Gas, and others – No appliance failed AGA Index or ANSI limits with LNGs – CO is most sensitive measure of performance – Some appliances have high CO with ‘hot’ LNGs • Indices developed for older appliances do not always predict behavior of new, high-efficiency appliances
Effects of Fuel Changes: Appliances and Industrial Burners • Different appliance burners show changes in performance • No burner exhibited a failure case of flame lifting, excessive yellow tipping, or high CO emissions • Important performance characteristics are different for industrial burners than for residential appliances • Industrial burners are monitored more closely but operated at more demanding conditions Source: Gas Technology Institute
Effects of Fuel Changes: Appliances and Industrial Burners • Industrial burners can be categorized – Some burner types, like appliances, are relatively unaffected by changing fuel • Burners sensitive to changing fuel include: – Burners for which flame temperature changes strongly impact the process – Burners in high temperature processes or where emissions are tightly regulated – Burners operating close to stability limits • Only sensitive burner types need to be evaluated for gas interchangeability
Industrial Burners – Interchangeability Concerns • Unlike appliances, industrial burners are complex, highly engineered, and operate under precisely controlled conditions • Changing fuel can affect industrial burners – Performance • Flame length, temperature, flame shape, mixing patterns, etc. – Safety • Stability, operating range, air/fuel ratio, etc. – Meeting regulations • Emissions of NOx, CO, etc. • Wobbe is still best index of interchangeability
What Needs to be Learned? Application Concern Status Need Appliances Millions of unregulated units Studies made, results must be compared Testing of old, maladjusted, and new units Commercial/ Industrial Burners Widest range of use, efficiency, emissions Not yet addressed Extensive testing Engines and Boilers Knock, efficiency, emissions, stable combustion Mobile engines Review mobile studied, others engine data and not yet addressed testing Turbines/ Microturbines Efficiency, New FL study emissions, turbine planned with fulllife scale turbines Collect turbine maker data and testing Non-combustion Uses Added process cost, plant modification Market analysis and data collection Not yet addressed
Work Scope • Receipt of – – Survey of northeast industrial gas customers by SIC (or NAICS) code, engines, turbines – Current natural gas and expected LNG ranges • Identification of industrial burners used by specific industrial customers – largest combustion uses • Itemizing of engines and turbines by manufacturer, model, type, and quantity • Ranking of burners, engines, and turbines into categories – considering gas composition ranges • Explanations provided of interchangeability reasons for placement of combustion systems into categories
Ranking Criteria • Burners and processes not expected to have any operational, performance, or emissions concerns over the full range of specified fuel gas compositions • Burners and processes that may have some concerns over the specified fuel gas range and may eventually need to be looked at more closely. These include – those considered to be of some concern, but likely will handle the charges in gas composition with no difficulties – those for which insufficient information is available and may need to be studied before making a judgment • Burners and processes with operations, performance, or emissions concerns over at least part of the range of gas compositions. Further study would be advised for these systems before introducing a new fuel gas such as LNG.
Deliverable – Final Report • Summary overview of industrial burners, engines, and turbines identified in survey – Number and type listed where possible – Burner types summarized by SIC codes • Analysis of burners, engines, and turbines – General comments on impacts of proposed gas ranges on listed combustion systems – Ranked in three classes based on changing gas • Little or no impact expected • Some impact expected or too little information available to decide about impacts • Impacts expected and more detailed study of combustion systems recommended
Cost and Schedule • Cost – Project cost - $69, 000 – Includes initial and final trips to meet with sponsors • Schedule – Work planned from June 15, 2006 through August 15, 2006 – GTI will start work immediately with partial survey results – Work completion is dependent on completed Northeast Stakeholders Group surveys – Work can be slowed if all survey results are not available
Classification of Industrial Burners
Classification Criteria 1. Mixing Type 2. Fuel Type 3. Oxidizer Type 4. Draft Type 5. Heating Type 6. Burner Geometry
Classification Criteria 1. Mixing Type 2. Fuel Type 3. Oxidizer Type 4. Draft Type 5. Heating Type 6. Burner Geometry • Diffusion Mixed – Non-Staged – Air Staged – Fuel Staged • Partial Pre-mixed – Non-Staged – Air Staged • Pre-Mixed – Non-Staged GTI Proprietary & Confidential
Classification Criteria 1. Mixing Type 2. Fuel Type 3. Oxidizer Type 4. Draft Type 5. Heating Type 6. Burner Geometry • • Gas Liquid Solid Dual
Classification Criteria 1. Mixing Type 2. Fuel Type 3. Oxidizer Type 4. Draft Type 5. Heating Type 6. Burner Geometry • • Air Oxygen Enriched Air Preheated Air
Classification Criteria 1. Mixing Type 2. Fuel Type 3. Oxidizer Type 4. Draft Type 5. Heating Type 6. Burner Geometry • • Forced Draft Natural Draft Inspirated Aspirated
Classification Criteria 1. Mixing Type 2. Fuel Type 3. Oxidizer Type 4. Draft Type 5. Heating Type 6. Burner Geometry • Direct • Indirect
Classification Criteria 1. Mixing Type 2. Fuel Type 3. Oxidizer Type 4. Draft Type 5. Heating Type 6. Burner Geometry • Round Nozzle • Rectangular Nozzle • Swirl
Burner Types 1. Radiant Burners 2. High Velocity Burners 3. Regenerative Burners 4. Natural Draft Burners 5. Boiler Burners 6. Linear Grid / In-Duct Burners 7. Oxygen Enhanced / Oxy-Fuel Burners 8. Flare Burners
Burner Types 1. Radiant Burners 2. High Velocity Burners 3. Regenerative Burners 4. Natural Draft Burners 5. Boiler Burners 6. Linear Grid / In-Duct Burners 7. Oxygen Enhanced / Oxy-Fuel Burners 8. Flare Burners • Radiant Wall • Thermal Radiation • Radiant Tube
Burner Types 1. Radiant Burners 2. High Velocity Burners 3. Regenerative Burners 4. Natural Draft Burners 5. Boiler Burners 6. Linear Grid / In-Duct Burners 7. Oxygen Enhanced / Oxy-Fuel Burners 8. Flare Burners • Radiant Wall – Natural Draft – Forced Draft • Pre-mixed • Non-Premixed • Thermal Radiation • Radiant Tube
Burner Types 1. Radiant Burners 2. High Velocity Burners 3. Regenerative Burners 4. Natural Draft Burners 5. Boiler Burners 6. Linear Grid / In-Duct Burners 7. Oxygen Enhanced / Oxy-Fuel Burners 8. Flare Burners • Radiant Wall • Thermal Radiation – – – – Porous Ceramic Ported Ceramic Fiber Metal Flame Impingement Catalytic Perforated Ceramic Porous Refractory Wire Mesh • Radiant Tube
Burner Types 1. Radiant Burners 2. High Velocity Burners 3. Regenerative Burners 4. Natural Draft Burners 5. Boiler Burners 6. Linear Grid / In-Duct Burners 7. Oxygen Enhanced / Oxy-Fuel Burners 8. Flare Burners • Radiant Wall • Thermal Radiation • Radiant Tube – – Non-Circulating Recirculating Forced Draft Inspirating
Burner Types 1. Radiant Burners 2. High Velocity Burners 3. Regenerative Burners 4. Natural Draft Burners 5. Boiler Burners 6. Linear Grid / In-Duct Burners 7. Oxygen Enhanced / Oxy -Fuel Burners 8. Flare Burners • • Pre-mixed Diffusion Mixed Partially Pre-mixed Air Staged
Burner Types 1. Radiant Burners 2. High Velocity Burners 3. Regenerative Burners 4. Natural Draft Burners 5. Boiler Burners 6. Linear Grid / In-Duct Burners 7. Oxygen Enhanced / Oxy. Fuel Burners 8. Flare Burners • One Box • Two Box • Rotary / Heat Wheel • Radiant Tube
Burner Types 1. Radiant Burners 2. High Velocity Burners 3. Regenerative Burners 4. Natural Draft Burners 5. Boiler Burners 6. Linear Grid / In-Duct Burners 7. Oxygen Enhanced / Oxy. Fuel Burners 8. Flare Burners • Round Flame • Wall Fired Flat Flame • Radiant Wall • Flat Flame
Burner Types 1. Radiant Burners 2. High Velocity Burners 3. Regenerative Burners 4. Natural Draft Burners 5. Boiler Burners 6. Linear Grid / In-Duct Burners 7. Oxygen Enhanced / Oxy-Fuel Burners 8. Flare Burners • Low NOx • Ultra Low NOx • Conventional
Burner Types 1. Radiant Burners 2. High Velocity Burners 3. Regenerative Burners 4. Natural Draft Burners 5. Boiler Burners 6. Linear Grid / In-Duct Burners 7. Oxygen Enhanced / Oxy. Fuel Burners 8. Flare Burners • Low NOx – External Flue Gas Recirculation (EFGR) – Air Staged – Fuel Induced Recirculation • Ultra Low NOx • Conventional
Burner Types 1. Radiant Burners 2. High Velocity Burners 3. Regenerative Burners 4. Natural Draft Burners 5. Boiler Burners 6. Linear Grid / In-Duct Burners 7. Oxygen Enhanced / Oxy-Fuel Burners 8. Flare Burners • Low NOx • Ultra Low NOx – – Pre-mixed Partially Premixed Rapid Mix Internal Flue Gas Recirculation • Conventional
Burner Types 1. Radiant Burners 2. High Velocity Burners 3. Regenerative Burners 4. Natural Draft Burners 5. Boiler Burners 6. Linear Grid / In-Duct Burners 7. Oxygen Enhanced / Oxy-Fuel Burners 8. Flare Burners • Low NOx • Ultra Low NOx • Conventional – Swirl – Register
Burner Types 1. Radiant Burners 2. High Velocity Burners 3. Regenerative Burners 4. Natural Draft Burners 5. Boiler Burners 6. Linear Grid / In-Duct Burners 7. Oxygen Enhanced / Oxy-Fuel Burners 8. Flare Burners • Duct – Linear Grid – Grid • Make-up Air
Burner Types 1. Radiant Burners 2. High Velocity Burners 3. Regenerative Burners 4. Natural Draft Burners 5. Boiler Burners 6. Linear Grid / In-Duct Burners 7. Oxygen Enhanced / Oxy. Fuel Burners 8. Flare Burners • Air-Oxy Fuel – – Concentric Pipe Multiple Nozzle Flat Flame Staged • Oxy-Fuel – Polishing – Forehearth
Burner Types 1. Radiant Burners 2. High Velocity Burners 3. Regenerative Burners 4. Natural Draft Burners 5. Boiler Burners 6. Linear Grid / In-Duct Burners 7. Oxygen Enhanced / Oxy. Fuel Burners 8. Flare Burners • Single Point – Non Assisted – Simple Steam Assisted – Advanced Steam Assisted – Low Pressure Air Assisted • Multi-point • Enclosed
Burner Types 1. Radiant Burners 2. High Velocity Burners 3. Regenerative Burners 4. Natural Draft Burners 5. Boiler Burners 6. Linear Grid / In-Duct Burners 7. Oxygen Enhanced / Oxy. Fuel Burners 8. Flare Burners • Single Point • Multi-point – Non Assisted – Simple Steam Assisted – Advanced Steam Assisted – Low Pressure Air Assisted • Enclosed
Burner Types 1. Radiant Burners 2. High Velocity Burners 3. Regenerative Burners 4. Natural Draft Burners 5. Boiler Burners 6. Linear Grid / In-Duct Burners 7. Oxygen Enhanced / Oxy. Fuel Burners 8. Flare Burners • Single Point • Multi-point • Enclosed – Non Assisted – Simple Steam Assisted – Advanced Steam Assisted – Low Pressure Air Assisted
Burner Applications 1. Radiant Burners 2. High Velocity Burners 3. Regenerative Burners 4. Natural Draft Burners 5. Boiler Burners 6. Linear Grid / In-Duct Burners 7. Oxygen Enhanced / Oxy-Fuel Burners 8. Flare Burners • Thermal Radiation – Drying – Plastic thermoforming – Paint curing • Radiant Tube – Indirect heating • Radiant Wall – Process Industry
Burner Applications 1. Radiant Burners 2. High Velocity Burners 3. Regenerative Burners 4. Natural Draft Burners 5. Boiler Burners 6. Linear Grid / In-Duct Burners 7. Oxygen Enhanced / Oxy. Fuel Burners 8. Flare Burners • Metals Industry • Ceramic/Glass Industry
Burner Applications 1. Radiant Burners 2. High Velocity Burners 3. Regenerative Burners 4. Natural Draft Burners 5. Boiler Burners 6. Linear Grid / In-Duct Burners 7. Oxygen Enhanced / Oxy. Fuel Burners 8. Flare Burners • Zinc Distillation • Metals Industry • Glass Industry
Burner Applications 1. Radiant Burners 2. High Velocity Burners 3. Regenerative Burners 4. Natural Draft Burners 5. Boiler Burners 6. Linear Grid / In-Duct Burners 7. Oxygen Enhanced / Oxy. Fuel Burners 8. Flare Burners • Chemical and Hydrocarbon Process Industries
Burner Applications 1. Radiant Burners 2. High Velocity Burners 3. Regenerative Burners 4. Natural Draft Burners 5. Boiler Burners 6. Linear Grid / In-Duct Burners 7. Oxygen Enhanced / Oxy. Fuel Burners 8. Flare Burners • Steam Generation • Water Heating • Space Heating
Burner Applications 1. Radiant Burners 2. High Velocity Burners 3. Regenerative Burners 4. Natural Draft Burners 5. Boiler Burners 6. Linear Grid / In-Duct Burners 7. Oxygen Enhanced / Oxy-Fuel Burners 8. Flare Burners • Space Heating • Turbine Exhaust • Uniform Spread Heating
Burner Applications 1. Radiant Burners 2. High Velocity Burners 3. Regenerative Burners 4. Natural Draft Burners 5. Boiler Burners 6. Linear Grid / In-Duct Burners 7. Oxygen Enhanced / Oxy. Fuel Burners 8. Flare Burners • • Metal Heating Metal Melting Glass Melting Mineral Calcining
Burner Applications 1. Radiant Burners 2. High Velocity Burners 3. Regenerative Burners 4. Natural Draft Burners 5. Boiler Burners 6. Linear Grid / In-Duct Burners 7. Oxygen Enhanced / Oxy. Fuel Burners 8. Flare Burners • Petrochemical Industries
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