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API 73 rd Fall Refining and Equipment Standards Meeting. Los Angeles November 10, 2008. Combustion Analysis Options for Process Heaters. David Fahle – VP of Marketing Hydrocarbon Processing. precision and expertise. ENABLE YOU TO GO FURTHER. Experts in Gas Analysis. Markets. Products.

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Los Angeles November 10, 2008


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    1. API 73rd Fall Refining and Equipment Standards Meeting Los Angeles November 10, 2008

    2. Combustion Analysis Options for Process Heaters David Fahle – VP of Marketing Hydrocarbon Processing

    3. precision and expertise ENABLE YOU TO GO FURTHER

    4. Experts in Gas Analysis Markets Products Technology Support • Process Oxygen • Photometric • Combustion • Laser • OEM transducers • Analytical Systems • Industrial Gas • Hydrocarbon Processing • OEM Transducers • Paramagnetic • Zirconia • Photometric • Thick Film • Tuneable Diode Laser • Product Support • Committed to your Success • Quality Focus Gas Analysis is what we do - And we do it best

    5. Servomex Controls Limited formed 1952 First paramagnetic cells made based on licence from Distillers 1961 Bought by Sybron Corporation and integrated into Taylor Instruments Group 1971 MBO from Sybron Corporation 1987 Stock market flotation (London Stock Exchange) 1989 Acquired by The Fairey Group 1999 The Fairey Group renamed as Spectris plc 2001 Servomex Proud 50 Year History

    6. Global Presence Global Presence

    7. Combustion Applications

    8. Index of Applications • Thermal power generation • Incineration • HydrocarbonProcessing • Industrial Gases • Specialty Chemicals and Pharmaceuticals • Cement • Iron and steel

    9.  HydrocarbonProcessing

    10. Application Types Process Heaters Direct-fired heat exchanger that uses the hot gases of combustion to raise the temperature of a feed flowing through coils of tubes aligned throughout the heater. Typical temperatures 400°C-550°C (800-1000°F) Thermal Crackers Heat exchanger where reactions take place while the feed travels through the tubes, i.e. Ethylene cracking furnace. Typical temperatures 980°C-1200°C (1800-2200°F) On-site Incinerators Designed to combust both solid and liquid chemical waste. The type depends upon the type of waste being disposed and include fluidized bed, multiple hearth and rotating kiln incinerators. Typical temperatures 1100°C (2000°F) or greater.  HydrocarbonProcessing

    11. Process Heaters and Thermal Crackers - pipes run inside heating chamber to transfer heat Application Types  HydrocarbonProcessing

    12. Why measure gases during combustion? • Detecting oxygen rich conditions: O2 measurement • Detecting fuel rich conditions: CO measurement • Combustion Analyzer Types

    13. Combustion:Why measure gases? Complete Combustion CxHy + (x+(y/4))O2 xCO2 + (y/2)H2O +HEAT FUEL + OXYGEN  CARBON DIOXIDE + WATER + HEAT

    14. Combustion Efficiency Ideal FUEL RICH incomplete combustion % CO Too little oxygen = some fuel not burnt: 2000ppm excess CO above ideal means 1% extra fuel cost O2 -20 -10 0 10 20 % Excess Air

    15. Combustion Efficiency Ideal FUEL RICH incomplete combustion AIR RICH complete combustion % CO Too much air = cooling effect: 1.5% excess oxygen above ideal means 1% extra fuel cost Too little oxygen = some fuel not burnt: 2000ppm excess CO above ideal means 1% extra fuel cost O2 -20 -10 0 10 20 % Excess Air

    16. Combustion Efficiency FUEL RICH 20 AIR RICH 16 NOx CO 12 EFFICIENCY 8 4 IDEAL O2 0 10 20 -20 -10 % Excess Air

    17. Review - Breakthrough Concept Example 1: Coal data, 10h sample

    18. Review - Breakthrough Concept Example 1: Coal data, 1h

    19. Review - Breakthrough Concept Example 1: Coal data, 5mins

    20. Review - Breakthrough Concept Example 2: Gas data, 3 week sample

    21. Review - Breakthrough Concept Example 2: Gas data, 10h sample

    22. Combustion Efficiency FUEL RICH 20 AIR RICH 16 NOx CO 12 EFFICIENCY 8 4 IDEAL O2 0 10 20 -20 -10 % Excess Air

    23. Combustion Control: O2 Measurement Detecting air rich conditions How can oxygen be measured? Paramagnetic High accuracy Need extractive sample system with moisture removed “Zirconia” (zirconium oxide, ZrO2) based analysers Suitable accuracy, measure hot and wet Fast analysis, low maintenance and low cost Tuneable Diode Laser In-situ analysis Hot, corrosive, particulate latent samples

    24. Combustion Control: O2 Measurement Detecting air rich conditions Paramagnetic Technology

    25. SO2 O2 CO2 O2 SO2 CO2 CO HCl N2 CO Oxygen is unique. It is strongly attracted into a magnetic field. It is described as being “ paramagnetic ” O2 O2 O2 O2 O2 O2 O2 O2 O2 O2 O2 O2 NO NO O2 O2 O2 O2 O2 O2 NO2 NO2 NO2 O2 SO2 HCl CO2 CO SO2 SO2 CO2 HCl CO CO2 CO2 N2 CO HCl N2 N2 CO

    26. Paramagnetic Cell Magnet pole pieces Nitrogen filled spheres Feed back coil Suspension & mirror LED source Photocell sensor

    27. Combustion Control: O2 Measurement Detecting air rich conditions Paramagnetic Technology Provides: Performance • Fast response • Exceptional linearity and repeatability • High stability & accuracy Economics • Long operational life • Extractive sample system required • Simple validation / calibration

    28. Combustion Control: O2 Measurement Detecting air rich conditions Zirconia Oxide Technology

    29. Zirconia disk Electrodes Combustion Control: O2 Measurement Detecting air rich conditions Zirconium oxide (zirconia) based techniques Heated Chamber At high temperatures, zirconia conducts electricity through the movement of oxygen ions.

    30. 0 100 Combustion Control: O2 Measurement Detecting air rich conditions Zirconium oxide (zirconia) based techniques When the oxygen concentration on each side is different, an emf related to oxygen concentration is generated. Sample Reference Nernst Equation Cell output, E = K x Ln ( Pr/ Ps) mV assuming a constant cell temperature 7000C

    31. Combustion Control: O2 Measurement Detecting air rich conditions Zirconia Oxide Technology Provides: Performance • Fast response • Unaffected by background gases • Sample at hot / wet conditions Economics • Very acceptable operational life • Low maintenance requirements • Simple validation / calibration

    32. Combustion Control: O2 Measurement Detecting air rich conditions TDL Technology

    33. Based on Beer-Lambert law Used both in UV and IR Typical wideband techniques have low spectral resolution and sensitivity is limited by cross-interference The alternative is single line spectroscopy using tuneable diode lasers (TDL) TDL are available for a range of gases of interest Optical Absorption Spectroscopy

    34. Beer Lambert law: T = exp(-Sg(f)NL) T is transmission S is the absorption strength g(f) is the line shape function N is the concentration of absorbing molecules L is the optical path length Measuring T and knowing S, g(f) and L, N can be found Use single absorption lines in the NIR Optical Absorption Spectroscopy

    35. Single Line Spectroscopy Gas under test, typical absorption linewidth 0.05 nm Absorption lines from other (background) gases Laser scan range, typically 0.2 - 0.3 nm, note Laser spectral line width is ca. 0.0001 nm UV / IR absorption spectroscopy linewidth > 2 nm

    36. Choose a single absorption line from available databases Ensure no cross interference from other gases Typical Gas Mix for Waste Incinerator 10 mg/m3 HCl 15% H2O 6% O2 500 mg/m3 SO2 350 mg/m3 NOx 100 mg/m3 CH4 150 mg/m3 CO 10% CO2 Single Line Spectroscopy

    37. A single HCl line Laser scan range Single Line Spectroscopy Absorption spectrum for offgas from waste incinerator

    38. Measurement influences • Measurement influenced by: • Pressure • Temperature • Background gas composition • Just like conventional IR measurements! • Due to inter-molecular collisions, which strongly affect the absorption line: • its amplitude • Its width • Its shape (asymmetry) • Note: 2f WMS signal is just filtered version of line shape, so all information above is still available (non-linear relations however)

    39. Pressure influence • Frequency of collisions increases with gas density i.e. total pressure • Causes line broadening, hence the term “pressure broadening” • Line amplitude (per molecule) is unchanged • Small line centre shift occurs also • Maximum measurement pressure limited by pressure broadening smearing the line so as to overlap an adjacent line Pressure broadening measured for 2f WMS spectroscopy of O2 in N2

    40. Temperature influence • Changes gas density and molecular velocity distribution, hence collision frequency and line width • Temperature also changes thermal excitation of molecular vibrations, hence the line amplitude (per molecule) • Can be exploited to distinguish hot gas from cold gas e.g. 2900 (NEO) oxygen analyser From HITRAN database

    41. Combustion Control: O2 Measurement Detecting air rich conditions TDL (Tuneable Diode Laser) Provides: Performance • Fast response • In-situ measurement at process conditions • Temperature and moisture measurement possible Economics • Long operational life • Low maintenance requirements • Inferred validation

    42. Combustion Control: CO Measurement Detecting breakthrough and flooding How can CO be measured? Thick film High accuracy at process conditions Cost effective measurement in combination with O2 Tuneable Diode Laser In-situ analysis Hot, corrosive, particulate latent samples

    43. Combustion Control: CO via Thick Film Sensor Very thin platinum tracks are printed onto a ceramic disk.

    44. Combustion Control: CO via Thick Film Sensor Very thin platinum tracks are printed onto a ceramic disk. These form resistors in a “Wheatstone bridge”, an arrangement that allows small changes in resistance to be accurately detected.

    45. Combustion Control: CO via Thick Film Sensor Very thin platinum tracks are printed onto a ceramic disk. These form resistors in a “Wheatstone bridge”, an arrangement that allows small changes in resistance to be accurately detected. Each quadrant is thermally isolated from next by slots.

    46. Combustion Control: CO via Thick Film Sensor A special catalyst that is selective to CO is then printed over two quadrants

    47. Combustion Control: CO via Thick Film Sensor Any CO in the sample will burn on the surface of the catalytic material, creating a change in temperature. CO CO CO CO CO CO CO CO CO CO CO CO CO

    48. Combustion Control: CO via Thick Film Sensor CO CO CO CO CO CO CO CO CO CO CO The change in temperature is detected by the platinum tracks underneath, changing their resistance, which can be detected. CO CO

    49. ServoTOUGH Fluegas

    50. 700 B / N 700 Ex Servomex Combustion Analyzer History 2700