OXYDAN® Exhaust Gas Dilution Probe
Continuous Emission Monitoring made easy
The process relies on several key steps. Initially, a small portion of the stack’s contents is extracted and then subjected to a proprietary filter to eliminate any impurities. Subsequently, this filtered sample is meticulously mixed with clean, dry zero air, effectively lowering the dew point to prevent the formation of condensation in the sample line.
The resulting diluted sample is then pressurized and transported through an unheated sample line to the designated location where gas sensors or analyzers carry out their analysis.
The system’s verification / calibration is executed with meticulous precision by introducing span or zero gas directly into both the stack and the probe. This method guarantees a comprehensive validation of the entire sampling process, spanning from the probe’s tip to the final concentration readings. This meticulous approach results in exceptionally accurate measurement outcomes, distinguishing it from systems that solely verify sensors without considering the integrity of the sampling system.
The dilution probe system operates by utilizing a pressurized source of uncontaminated dry air, commonly referred to as ‘dilution air.’ It relies on an ejector, making the system practically solid-state with no moving parts that require maintenance or frequent repairs.
Once you establish a connection between the instrument air, sourced from a swing absorption dryer, and a power supply to activate the self-regulating heater, the probe will initiate the delivery of a properly diluted sample to your sensors or analyzers.
Features and benefits
- Unheated Sample Line
- Zero Velocity filter method
- Sample is transported at positive pressure, no ingress possible
- Sample gas virtually as clean as the ambient air
- No contamination of detectors/sensor optics
- No moving parts
- No loss of water-soluble gasses such as SO2, NO2 etc.
- Fast response time
- Direct “Wet Basis” Measurement
- Works with all ambient air analyzers / sensors such as “Thermo Scientific, Teledyne-API, Acoem/Ecotech, Horiba” and even low-cost ambient ECS
- CEMS Continuous Emission Monitoring Systems
- Process control SCR / SNCR
- Compliance verification EGCS SO2/CO2 emission ratio
- Portable sampling systems
- Process research
- GHG Green House Gas monitoring
Model | OXYDAN® DP7900:2017 / DP5 | |||||
Application | Continuous Emission Monitoring System / Process control | |||||
Sampling Method | Dilution / extractive | |||||
Dilution ranges *
| Orifice size | Sample Flow | 3,7 bar | 4,2 bar | 5 bar | 5,5 bar |
Sample | ~ ml/min. | Dil. Rate | Dil. Rate | Dil. Rate | Dil. Rate | |
8 | 50 | 304 | 318 | 377 | 413 | |
10 | 79 | 195 | 203 | 241 | 264 | |
12 | 113 | 135 | 141 | 168 | 183 | |
15 | 177 | 86 | 90 | 107 | 117 | |
17 | 227 | 67 | 70 | 83 | 91 | |
18 | 254 | 60 | 62 | 74 | 81 | |
20 | 314 | 48 | 50 | 60 | 66 | |
25 | 491 | 31 | 32 | 38 | 42 | |
30 | 707 | 21 | 22 | 26 | 29 | |
Dilution rates are approximated. Total sample flows 10 to 15 L / min. | ||||||
Sample gas temperature | Max. 500 °C (optional 1200°C) | |||||
Probe temperature ** | ~150 to 200 °C (self-controlling) | |||||
Particulate filter | Zero velocity filter, pore diameter down to 1 µm | |||||
Ambient temperature | Probe 0 to 90 °C | |||||
Instrument air | Consumption 10 to 15 NLPM | |||||
Instrument air requirements | Particles ISO8573:1 – 2001, Class 2 dirt (1 micron) Residual Oil Content < 0,01mg/m3 (Class 1: ISO 8573-1) Water content PDP -40°C =0,11 g/m3 (Class 2: ISO 8573-1) | |||||
Probe heater supply | Voltage 24VDC / 240V AC 50/60 Consumption 250W | |||||
Probe materials | Probe: Stainless steel 316L **** | |||||
Pneumatic connections | 8 / 6 / 4 mm SS316 compression fittings | |||||
Process connection | 1 1/4” G (other as flanges consult factory) | |||||
Probe size | ~ 35 x Ø13 cm (not including insulation jacket) | |||||
Probe weight *** | Probe 4 kg not including flange | |||||
Options | Quick Couplings – O2 sensor – Probe flanges consult factory – CAN Bus control box | |||||
* Dilution rates are nominal values, ** temperature controlled, *** With 1 ¼” process fitting, **** Optional SilcoTek’s SilcoNert® Coated “This material is for reference only. Instrumatic EMI A/S has taken all reasonable care to ensure the reliability of the information contained in this document, but makes no guarantees, warranties, or representations regarding the accuracy or completeness of the information. Any reproduction of this material requires prior permission from Instrumatic EMI A/S in writing.” Subject to change without notice – Instrumatic EMI © Copyright 2023. OXYDAN ® is the registered trademark of Instrumatic Holding ApS. | ||||||
- Unheated Sample Lines
The dilution technique offers a significant advantage by lowering the dew point of sample gas to below ambient temperature. This enables the use of unheated sample lines, eliminating costly maintenance associated with traditional heated lines. Failures in line heating systems and the occurrence of cold spots, which often lead to condensation and line plugging, become non-issues, resulting in substantial cost savings.
- Reduced Maintenance
A non-dilution extractive method requires large amount of sample gas, typically 2-5 litres per minute, this sample gas requires filtering and the removal of moisture from it before it can be measured by the analyzers. However, the dilution extractive method requires only a small amount of sample gas, around 100 – 300 cc/min. This increases the lifetime of the filter in the probe and eliminates the need for using a chiller to remove moisture; thus further decreasing the level of maintenance required. Dilution of acidic stack gases substantially reduces the risk of damage to accurate analyzers.
- Sample Gases aren’t lost
The straight extractive method requires that a water removal system is used prior to the sample reaching the analyzers. This process of removing water also removes part of the very water-soluble sample gases, thus introducing an error into the measurement of SO2, NO2 and others. By diluting the raw sample gas, the water content in the sample is reduced, and no removal of water required and therefore none of the water-soluble gases lost.
- Direct “Wet Basis” Measurement
The removal of water from the sample gas (extractive systems) alters the ratio of gases in the sample and this requires that sample temperature and a % moisture curve for saturated conditions in order to determine moisture contents of the stack gas and correct the reading of this loss of water.
However, by using the extractive dilution method moisture is not removed from the sample and therefore the measurement can be classified as a “wet basis” measurement without further corrections being required.
- Calibration gases last longer
An extractive dilution system only requires 100-300 cc/min of sample gas as opposed to the 2-5 litres required by extractive systems. Therefore, only 200-400 cc/min of calibration gas is required for a full calibration. Typically with daily calibrations a “D” size cylinder will last for up to two years.
OXYDAN DP7900:2017 / DP5 datasheet 2023
APPLICATION QUESTIONARY FOR DILUTION PROBE SYSTEM 2023
OXYDAN DP7900 Stack Unit 5.0 Manual
Sintered SS sample filter Ø22X60
Sample pipe length extension 500 – 2000 mm
High temp sample pipe 1200°C length max. 1500 mm
Blow-Back System for sample pipe (high dust application)
SilcoTek® coated probe liner, filter-cartridge & vacuum ejector
O2 transmitter with analog output 4-20 mA includes including ZRDO sensor.
Dilution air generator (portable or fixed)
19” Rack Probe control panel with vacuum and pressure gauges, precision regulator, 3 way calibration valve and flowmeter.