Model EXAxt AV550G. Averaging Oxygen Analyzer

Transcription

1 Model EXAxt AV550G Averaging Oxygen Analyzer

2 Oxygen Measurement and Flyash Oxygen % vs cell EMF The O2 mation, model AV550, averaging oxygen analyzer was designed with a focus Calibration 1 on practical performance. Pressure induced calibration Yokogawa has refined its expertise in the combustion oxygen business into this new and creative product. It is packed with features designed to minimize plant down time and technical support for the oxygen measurement. Its intuitive color touch screen operation, powerful new process diagnostic tools and creative hardware design makes power boiler oxygen trim automation simple, predictable and reliable. The accumulation of flyash on the zirconia cell affects its ability to measure oxygen concentration. Flyash and its constituents can reduce the life of the zirconia cell and affect the cells response time to changes in gas concentration. Yokogawa s large surface area sintered metal filters are designed to keep particulate and ash off the measurement cell. With time, even the best filter mesh can become plugged with flyash. Even a moderately plugged filter can have dramatic effect on the oxygen measurement. Errors can occur during calibration when calibration gas flowing to the cell becomes trapped in the space between the cell and the plugged filter. This effectively raises the gas pressure around the measurement cell causing a left shift of the calibration curve. The resulting oxygen measurement is lower than the actual oxygen concentration. This is called pressure-induced drift. A 2psi pressure increase can induce a measurement error 0.5% oxygen lower than the actual oxygen concentration in the process. This error is significant considering the current industry emphasis on emissions and fuel usage. The boiler operator will inject more air into the combustion process to achieve the oxygen control set point; creating problems with NOx generation and an increased use of fuel. The O2mation asymmetry alarm provides users information about pressure induced drift and other calibration errors by monitoring the particular symptoms that effect calibration.

3 Features Full color touch screen operation Multiple display modes shows average, single or all detector gas concentrations Handles input of up to 8 oxygen detectors Redundant channel systems using multiple CPUs "Hot swap" of channel cards so the analyzer remains on line during maintenance Eight 4-20mA outputs for individual detectors Three 4-20mA outputs for average oxygen concentration outputs Failed, in calibration, or alarming, detectors are automatically excluded from average calculations Automatic or manual type calibration methods 24V or 120VAC auto-calibration power option Contact input allows calibration activation, range change and detector performance validation Intuitive "common language" operation Housing temperature alarm to notify user of over temperature conditions on the electronics Trend graphing allows normal and stacked trend views of oxygen concentrations Smart calibration uses historical calibration data to estimate when the next calibration should occur Asymmetry alarm uses historical calibration data to determine possible measurement errors due to process condition changes Remote Validation permits control room activation of zero, span or midpoint gas concentrations without running an actual calibration. Cal line purge function allows the gas purge of calibration lines of condensation before the detector is heated up to prevent water damage to the zirconia cell.

4 ZR Detector Features Developed from the field proven ZO21D zirconia detector technology, the EXAxt ZR22 in-situ type zirconia detector provides dependable and accurate oxygen measurement. Available in lengths from 15 cm to 5 meters, the ZR22 can be used in process temperatures up to 700ºC and pressurized ducts up to 36 psig with the pressure compensating option. The new detector's modular design incorporates a rebuildable heater and thermocouple assembly, the industry standard Yokogawa zirconia cell, and removable reference and calibration lines to create an oxygen measurement product designed for simple, quick and low-cost field maintenance. Rebuildable, field maintainable design Proven Zirconia sensor technology Optional filters or flame arrestors Multiple flange size options

5 The Magic Touch The intuitive touch screen virtually eliminates the need for an instruction manual. The trend graph helps diagnose problems and view individual detector performance over time. Touch Screen Trend Graph Detail Display 8-Channel Display Alarm Status Maintenance Single Channel and Average Data Display Trend Graph Modular Construction Maintenance and inspection are simplified by a modular hardware design. The Hot Swap feature allows changing channel modules without powering off the analyzer. Each channel card is fitted with spacious, and accessible, self-trapping terminal strips that make wiring and maintenance fast and easy.

6 Averaging - Fuel and NOx A 10% change in excess 0 2 is a 1% change in fuel usage! Customers concerned with lowering NOx emissions are making tremendous changes to accommodate EPA regulatory requirements. A substantial number of these changes include the expansion and upgrade of the plant combustion oxygen measurement equipment. Power plant engineers, betterment groups, operators, boiler manufacturers and engineering firms understand the direct relationship between excess air, NOx and fuel usage in the combustion process. There is a direct correlation between the amount of excess air and the production of NOx: NOx vs Excess O2 BETWEEN THE AMOUNT OF FUEL USED AND EXCESS AIR. A 10% CHANGE IN EXCESS AIR IS A 1% CHANGE IN FUEL USAGE. THERE IS A DIRECT CORRELATION The purpose of the O2 measurement is to find the best representative sample of what is happening in the combustion fireball. Combustion and exhaust duct variances cause areas of high and low O2 in the flue gas duct resulting in a condition called stratification. AVERAGE A single point O2 measurement can miss areas of stratification and allow substantial errors in the excess O2 measurement. Multiple sample points reduces this error!

7 Oxygen Measurement and Flyash Oxygen % vs cell EMF The O2 mation, model AV550, averaging oxygen analyzer was designed with a focus Calibration 1 on practical performance. Pressure induced calibration Yokogawa has refined its expertise in the combustion oxygen business into this new and creative product. It is packed with features designed to minimize plant down time and technical support for the oxygen measurement. Its intuitive color touch screen operation, powerful new process diagnostic tools and creative hardware design makes power boiler oxygen trim automation simple, predictable and reliable. The accumulation of flyash on the zirconia cell affects its ability to measure oxygen concentration. Flyash and its constituents can reduce the life of the zirconia cell and affect the cells response time to changes in gas concentration. Yokogawa s large surface area sintered metal filters are designed to keep particulate and ash off the measurement cell. With time, even the best filter mesh can become plugged with flyash. Even a moderately plugged filter can have dramatic effect on the oxygen measurement. Errors can occur during calibration when calibration gas flowing to the cell becomes trapped in the space between the cell and the plugged filter. This effectively raises the gas pressure around the measurement cell causing a left shift of the calibration curve. The resulting oxygen measurement is lower than the actual oxygen concentration. This is called pressure-induced drift. A 2psi pressure increase can induce a measurement error 0.5% oxygen lower than the actual oxygen concentration in the process. This error is significant considering the current industry emphasis on emissions and fuel usage. The boiler operator will inject more air into the combustion process to achieve the oxygen control set point; creating problems with NOx generation and an increased use of fuel. The O2mation asymmetry alarm provides users information about pressure induced drift and other calibration errors by monitoring the particular symptoms that effect calibration.

8 Specifications Measurement: Oxygen in combustion exhaust gas or non-flammable gas mixtures Measurement system: Zirconia type Measurement range: Display: 0 to 100% (3-digit display) Output: Any setting in the range from 0 to 5 vol% O2 to 0 to 100 vol% O2 Number of detectors: 1 to 8 Detector Compatibility: ZR22G, ZR225, Z021D, Z021DW Power Supply: 86 to VAC, 50/60 Hz Power Consumption: Max: 1kw During Startup Max: 1.8kw Performance: Repeatability: +/- 0.5% F.S. Linearity: +/- 1% F.S. (less than 0 to 25% range) Drift: +/- 2% F.S./month for both zero and span Response: 5 sec maximum for 90% response Display: 5.7 inch full color display 320 x 240 touch screen Analog output signals: (Average value outputs, individual channel outputs) Range: Settable in the range from 0 to 5% to 0 to 100 % O2 4 to 20 ma DC input/output isolated Contact output signals: 5 points, contact rating 30 VDC 3A, 250 VAC 3A (resistive load) Normally energized or de-energized, selectable Self-diagnostics: Cell, temperature, analog circuit, digital circuit, calibration, ROM/RAM error power loss Calibration function: One-touch calibration, automatic calibration Construction: Indoor installation (for outdoor installation, rainproof case is required) Ambient Temp: -5 to +50 C Outside Dimensions What does vigilance mean to Yokogawa? For starters, always making sure the products and solutions that leave our research and development labs are the best the world has seen - from day one throughout your business life cycle. Our innovative technologies and committed experts help design, install and manage your production systems efficiently and dynamically. In an ever-changing business environment, we help plan for the future to ensure continuity and flexibility in your automation strategies. Yokogawa goes the extra mile to do things right. Let us be vigilant about your business. Yokogawa Corporation of America 2 Dart Road, Newnan, GA , USA Phone: Fax: Represented by: The contents of this document are subject to change without prior notice. All rights reserved. Copyright 2004 Yokogawa Corporation of America. Printed in USA BUXXXXXXXXXXX