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Removing the Guesswork from Furnace Atmosphere Control with Laser Gas Analysis. Atmosphere Recovery, Inc. 15800 32nd Avenue North, Suite 110 Plymouth, MN 55447 Ph: (763) 557-8675 Fax: (763) 557-8668 Web: www.atmrcv.com E-mail: rrr@atmrcv.com. Presentation Outline.
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Removing the Guesswork from Furnace Atmosphere Control with Laser Gas Analysis Atmosphere Recovery, Inc. 15800 32nd Avenue North, Suite 110 Plymouth, MN 55447 Ph: (763) 557-8675 Fax: (763) 557-8668 Web: www.atmrcv.com E-mail: rrr@atmrcv.com
Presentation Outline • Application Introduction • Existing Technology Limitations • Laser Gas Analyzer Technology • Economic Benefits of LGA • Example Process Applications • Standard Carburizing • Rapid Carburizing • Exothermic Annealing
Industrial Furnace Atmospheres – Similar Constituents • Carburizing, Carbonitriding, FNC & Nitriding • N2, CO, H2, CO2, H2O, CH4, O2, NH3, CH3OH • Atmosphere Tempering and Annealing • N2, H2, CO, CO2, H2O, CH4, O2, NH3, Ar • Steel, Copper and Aluminum Brazing • N2, H2, CO, CO2, H2O, CH4, O2, NH3, Ar • Powdered Metal Sintering and Annealing • H2, N2, CO, CO2, H2O, CH4, O2,NH3, H2S
Atmosphere Conceptual Needs –Better Control, Less Use Waste Gas Amounts H M L Natural Gas and Other Fuels Fixed Flow or Single Gas High Gas Use (H) Std. Multi-Gas Adds Control Med. Gas Use (M) Industrial Process Gas Furnace Process Gases and Liquid (Vapors) Complete Gas Control/Reuse Low Gas Use (L)
Typical Atmosphere Control - Measures Only One Gas Species • Types • Zirconia Oxygen Probe – Measures Oxygen • Dew Point Meters – Measures Water Vapor • Electrochemical Cells – Low Range Single Gases • Benefits • Proven Technology • Lower Capital Cost • Low Complexity • Disadvantages • Other Gas Constituents Assumed (Guessed) • Assumptions Often Wrong • Limits Process Control & Improvement Options • Requires High Process Atmosphere Flows
Improved Atmosphere Control –Single Gas Plus Infra-Red • Economically Measures Three More Gases • Carbon Monoxide • Carbon Dioxide • Methane • Benefits • Proven Technology and Vendors • Can be Used to Reduce Atmosphere Use • Disadvantages • Cannot Measure Hydrogen, Nitrogen and Inerts • Expensive to Measure Other Significant Gases • Limited Measurement Range • Requires Frequent Calibration • Limits High Efficiency Atmosphere Gas Mixtures • Can’t Significantly Reduce Atmosphere Use
Other Gas Analysis Technologies –Not Very Applicable to Atmospheres • Gas Chromatography (GC) • High Capital Cost ($15,000 - $60,000) • Slow (2 Minutes+) • Complex – Use Requires Training • Carrier Gas and Frequent Calibration • Few Used for Atmosphere Control • Mass Spectroscopy (MS) • Higher Capital Cost ($50,000 - $120,000) • Best Applied on Vacuum Processes • Expensive to Maintain • Many Gases Cannot be Determined (Equal Mass)
Ultimate Atmosphere Control Goal –Practical Complete Gas Analyzer • Measure All Gases • Except Inert Gases (Can be Inferred) • Low Levels of Oxygen (Work with Existing Controls) • Dew Point Range of –40 Deg. C (or F) and Up • Monitoring of Any Industrial Atmosphere • Fast Analyzer Response • Compact and Operator Friendly • Rugged, Reliable, Easy to Service • Minimal Calibration • Cost-Effective
Laser Raman Spectroscopy - Why Selected? • Unique Frequency “Shift” for Each Chemical Bond • Little Interference Between Most Gases • Measures Gases of All Types (Except Inerts) • Rapid “Real Time” Response Rates Possible • Signal Directly Proportional to Number of Gas Atoms • 0-100% Gas Concentrations with One Detector • Resolution and Accuracy Depends On: • Laser Power and Optics Variation • Gas Concentration and Pressure • Molecular Bond Type • Background and Scattered Radiation • Optical and Electronic Detector Circuitry • GOALS MET!
Core of Laser Gas Control – Unique 8 Gas Detector Gas to be Analyzed In Special Particle Filter 8 Optical Filters/Sensors (1 for Each Gas Measured) Gas Sample Tube Detector Assembly Laser Beam Plasma Cell Mirror Prism & Mirror Polarizer Gas Out Gas Out
LGA Detector Features • Internal Cavity-Based Raman • Low Power Laser (Helium-Neon Plasma) • Sample Gas Flows Through Instrument • Higher Inherent Accuracy • Discrete Optical Filtering and Quantifying • 8 Gases Detected – Can be Process Specific • Simultaneous Detection of Each Gas Species • Fast Detector Response (50 milliseconds) • Only High Nitrogen Dioxide Levels Interfere • Array Based Interference Computations
Gas Species Lower Limit Hydrogen - H2 100 ppm Nitrogen - N2 50 ppm Oxygen - O2 50 ppm Water Vapor - H2O 10-50 ppm* Carbon Monoxide - CO 50 ppm Carbon Dioxide - CO2 25 ppm Organics - CxHy 10-50 ppm* Ammonia - NH3 10-50 ppm* Standard Furnace Constituents Monitored and Detection Limits *Customer Selectable – Selecting Lower Value Limits The Upper Range to 30%; Other Gas Species Substitutable as Options
Gas Analyzer – Basic System View Integrated Computer & Control System Detector Assembly Sample Pump, Valves and Pressure Control
Analyzer System Features • Integrated Sampling and Calibration System • Internal Pump and Valves • Low Volume Sample Gas Flows (200 ml/minute) • Multiple Sample Port Options • Automated Zero and Span Calibration • Integrated Electronics & Software • Pentium/Pentium III Computer and Monitor • Customizable Windows Based OS • Local and Remote Displays and Data Storage • Available Analog and Digital I/O • Multiple Configurable Process and PLC Interfaces
Analyzer – Industrial Product Model 4EN Furnace Gas Analyzer Outside View Inside View
Industrial Product Features • “Real Time” Process Monitoring and Control (1 to 15 Seconds - Depends on Number of Ports and Options) • Operates with Existing PLCs and Sensors • Low Volume Sample Gas Flows (200 ml/minute) • Electronic Flow and Pressure Monitoring • Optics and Enclosure Inerting (Standard for Heat Treating Atmosphere Analysis) • Multiple Sample Ports (16 + Optional) • Sample Line Purge and Back-flush (Optional) • High Dew Point Atmosphere Operation (Optional) • Standard NEMA Enclosures
Economic Benefits of Laser GasAtmosphere Analysis and Control • Multiple Gas Analysis Capability = System Versatility • Economic Paybacks in Many Ways • Reduce Energy Costs • Increase Production Capacity • Improve Component Quality • Improve Component Consistency • Reduce Destructive Analysis Costs • Reduce Re-Work Costs • Better Process Documentation • Maintenance Early Warnings • Enhanced Furnace Safety Depends on System Functions Used
Benefits of Laser Gas Analysis -Surface Hardening Qualitywith Standard Atmospheres • Surface Carbon (or Nitrogen) Properties • Improved Surface Hardness • Controlled Surface Retained Austenite • Consistent Compressive Residual Stress • Reduced Intergranular Oxidation • Improved Same Batch Consistency • Improved Batch-to-Batch Consistency • Faster Cycle Times
Benefits of Laser Gas Analysis -Heat TreatingEnergy Savings • Atmosphere Gas Consumption Reduced Endothermic Example – 90%+ Exothermic Example – 50%+ • Extra Gas Generators Turned Off • Shorter Cycle Times Inherent Carburizing Example – 20% • Total Process Savings Significant Carburizing Example – 25% of Total Furnace Exothermic Example – 15% of Total Furnace
Example 96% Endo Savings Stack and Flare Shut Off Door and Burner Leaks Reduced Surface Combustion All-Case Furnace (Shown Under Standard Operation)
Benefits of Laser Gas Analysis –In-Situ Rapid Carburizing • Greatly Increased Production Capacity Example: Cycle time for ~1mm case reduced 50% • Up to 40% Energy Savings • Elimination of Endo Generators • Further Improved Product Quality • Reduced Sooting and Furnace Maintenance
System Paybacks in Less Than 12 Months * Includes Furnaces, Atmosphere Generators, and Ancillary Equipment if Plant New or Near Capacity