The Need
Waste gas, biogas, off-gas, blast furnace and coke oven gas are often used as fuel for boilers, reboilers, furnaces, gas turbines and incinerators. The highly variable BTU content makes it difficult to use these fuels efficiently, safely and with minimum emissions. This analyzer directly measures the flow of air needed to burn a flow of a variable composition fuel gas. It can be used to compensate for the non-uniformity in gas supplies and to aid in the efficient utilization of by-product and waste-gas streams as fuel.
The Solution
This Stoichiometric Air-to-Fuel ratio analyzer takes separate streams of the fuel and air supplies, mixes and ignites them internally and measures the products of combustion. Feed-forward process combustion control of the stoichiometric air/fuel ratio using the S A/F IQ analyzer ensures maximum efficiency and minimum emissions (NOx and CO). The analyzer delivers a very fast responding signal that enables the combustion control system to react quickly to the variability of the combustion fuel and to provide the right amount of excess air. For all fuels, the S A/F IQ Analyzer is both faster and more accurate at predicting air requirements than Wobbe-type instruments since it mimics the combustion process.
- Weatherproof sensor enclosure
- Zirconium oxide-based for reliable on-line measurement and control of variable BTU fuels
- Inherently corrects for any oxygen in the fuel gas and includes it in the reading
- Three analog outputs - oxygen, air/fuel ratio and Wobbe Index
- Two alarms
- Diagnostics
- RS-485
- Requires handheld or wall-mount IQ Link
- HART option available
- UL Listed, CE Compliant
| Specifications |
| Sensor Enclosure: |
General Purpose |
| Pressure Requirements: |
0.04 - 6% |
| Sample Inlet: |
5 psi minimum; 100 psi maximum* @ 1 scfm max. (*Optional Sample Pump available) |
| Air Inlet: |
10 psi minimum; 100 psi maximum @ 1 scfm max. |
| Analog Output: |
Three selectable current outputs: oxygen, Wobbe Index or Air/Fuel Ratio. The output can be 4-20 mA, 0-20 mA, 20-4 mA or 20-0 mA. |
| Response Time with a 10:1 By-pass Flow: |
5-7 seconds to start; 25-35 seconds to 90%. |
| Zero/Span Drift: |
Less than 2% in 7 days |
| Calibration Gas Requirements: |
2 cfh @ 5 psi |
| Alarms: |
Three oxygen alarms, high or low selectable and energize or deenergize on alarm. Assign alarm as O2, calibrate or verify. |
| Contact Rating: |
1A, 30V max., non-inductive load, AC or DC. |
| Diagnostics: |
Watchdog timer and service alarm |
| Environment: |
|
| Ambient Temperature: |
-20°C to +40°C |
| Sample Temperature: |
-20°C to +40°C |
| Power Requirements: |
115 VAC or 230 VAC, ±10% 47-63 Hz |
| Communications: |
RS-485, RS-232 (IQ Links), HART® Option available |
Specification Sheet
Application Note
Refer to the Specification Sheet in the Documentation tab to see the applicable certifications for this product.