Michell OptiPEAK TDL600 Moisture in Natural Gas Analyzer
Overview
The Michell OptiPEAK TDL600 is a tunable diode laser absorption spectroscopy (TDLAS) analyzer built specifically for automatic online measurement of moisture in natural gas and biomethane. It covers a measurement range of 1 to 1000 ppmV with a lower detection limit of 1 ppmV, and it is designed to cope with gas streams whose composition changes over time, such as blended pipeline gas, shale gas or upgraded biomethane. Because the laser never touches the gas, the analyzer avoids the sensor contamination and drift issues that affect contact-type hygrometers in demanding service, including sour gas.
Seven Star LLC supplies the Michell OptiPEAK TDL600 to gas processing, transmission and storage operators across Oman and the GCC, with engineering support in Muscat. Our team helps buyers specify the indoor or outdoor configuration, the sample system materials and the reporting units required by their gas sales agreements, so the analyzer arrives ready for commissioning on site.
Measurement Principle
TDLAS works by passing a narrow-linewidth laser beam through the sample gas and scanning the laser wavelength across a known water absorption line. Water molecules absorb energy at that specific wavelength, and the depth of the absorption feature is proportional to the moisture concentration. The OptiPEAK uses a dual-pass measurement cell, which provides good sensitivity while avoiding the high top-end saturation and maintenance burden associated with multi-pass Herriott cells. Built-in continuous laser optimization keeps the laser locked to the correct water peak, and a multi-stage temperature control system holds the laser within tight limits to protect measurement stability.
For the Michell OptiPEAK TDL600, the key challenge in natural gas is that the background gas itself changes the shape of the water absorption line. The analyzer addresses this with D-MET, a dynamic background gas compensation system that makes the moisture reading virtually independent of changes in methane content without manual correction factors. For streams with more than 2.5% CO2 or percentage-level H2S, a special calibration can be applied. The datasheet also confirms suitability for natural gas containing up to 20% hydrogen without further modification. On every update cycle the analyzer checks itself against its calibration data and compensates if necessary, which is particularly useful after a process upset.
Engineering Design of the Michell OptiPEAK TDL600
The Michell OptiPEAK TDL600 analyzer head is housed in a polyester-coated aluminum alloy explosion-proof enclosure rated IP66 and NEMA 4, mounted together with an in-house designed sample conditioning system on a 304L or 316L stainless steel panel or enclosure. The sample system applies filtration and multi-stage pressure reduction to deliver a clean, wholly gaseous sample to the cell. The analyzer accepts inlet pressures up to 100 barg, uses 1/4 inch NPT female gas connections and draws a cell flow of 0.5 Nl/min with a 1 to 5 Nl/min filter by-pass for fast response.
Operators of the Michell OptiPEAK TDL600 interact through a 4.3 inch color LCD with a capacitive touch pad, so configuration and interrogation can be done in the field without opening the enclosure or needing a hot-works permit. Electrical entry is through three M20 cable gland entries. Integration with plant systems uses three programmable 4 to 20 mA outputs, two configurable 4 to 20 mA inputs, three volt-free alarm contacts and RS485 Modbus RTU, while remote application software allows configuration of every Michell OptiPEAK TDL600 across remote, widely spaced sites.
Key Features
The main engineering advantages of the Michell OptiPEAK TDL600 for natural gas moisture duty are summarized below.
- Non-contact laser measurement means the optics are not exposed to glycol, hydrocarbon liquids or sour components that degrade conventional sensors.
- Measurement range of 1 to 1000 ppmV with a 1 ppmV limit of detection and accuracy of ±1 ppmV or ±3% of reading, whichever is greater.
- D-MET dynamic background gas compensation keeps readings stable when methane content varies between gas sources.
- Continuous laser optimization and tight laser temperature control reduce signal drift over long service intervals.
- Built-in self-verification checks the analyzer against its calibration data on every update cycle.
- Integrated sample conditioning system with filtration and multi-stage pressure reduction is supplied as part of the package.
- Reporting in ppmV, lb/MMSCF, mg/Nm3 or dew point in °C or °F using ISO 18453 or IGT#8 conversions.
- Hazardous area certification to ATEX, IECEx, UKCA (Ex db ib op is IIC T5 Gb) and cQPSus Class I Division 1.
Industrial Applications
The Michell OptiPEAK TDL600 is aimed at the points in the gas chain where water content is a contractual or safety limit. Typical installations include the outlet of triethylene glycol dehydration units, export and transmission pipelines, custody transfer metering stations, underground gas storage, LNG receiving and regasification terminals, vaporized NGL and biomethane injection points. In Oman these duties appear at upstream gas processing plants, at compressor and metering stations along the national gas transmission network, and at industrial consumers in the Sohar and Duqm zones that receive pipeline gas for power generation and petrochemicals.
Because the Michell OptiPEAK TDL600 tolerates sour gas and variable gas composition, it is a strong fit for GCC fields producing gas with elevated CO2 or H2S. Seven Star LLC supplies the Michell OptiPEAK TDL600 with the indoor version (+10 to +45 °C) for analyzer shelters, or the outdoor version with heater and an optional cooling package for shaded field locations where ambient temperature can reach 55 °C. Engineers comparing technologies can also review the ceramic-sensor Michell Easidew EA2 dew point transmitter, the Teledyne 8800B trace moisture analyzer and the Michell CD2-WDC-002 water dew-point sensor assembly.
For hydrocarbon dew point measurement on the same gas stream, see the Michell Condumax II hydrocarbon dew-point analyzer.
Technical Specifications
The table below lists the main Michell OptiPEAK TDL600 specifications taken from the manufacturer datasheet; confirm the final configuration against the order code before purchase.
| Parameter | Specification |
|---|---|
| Model | Michell OptiPEAK TDL600 |
| Measurement technology | Tunable diode laser absorption spectroscopy (TDLAS) |
| Measurement range | 1 to 1000 ppmV |
| Accuracy | ±1 ppmV or ±3% of reading, whichever is greater |
| Repeatability | ±0.5 ppmV or ±1.5% of reading, whichever is greater |
| Limit of detection | 1 ppmV |
| Units | ppmV, lb/MMSCF, mg/Nm3, dew point °C or °F (ISO 18453 or IGT#8) |
| Response | Display update 2 to 3 s |
| Inlet pressure | Maximum 100 barg (1450 psig) |
| Sample flow | 0.5 Nl/min cell; 1 to 5 Nl/min filter by-pass |
| Ambient (indoor / outdoor) | +10 to +45 °C / -20 to +45 °C; -20 to +55 °C with cooling option |
| Supply / power | 110 or 230 V AC 50/60 Hz; 80 W indoor, 180 W outdoor system |
| Outputs / inputs | 3 x 4–20 mA outputs, 2 x 4–20 mA inputs, 3 alarm contacts 250 V AC 3 A |
| Communications | RS485 Modbus RTU |
| Data logging | All process variables, sample period 10 s to 1 day |
| Enclosure | Aluminum alloy explosion-proof, IP66 / NEMA 4; sample system in 304L or 316L stainless steel |
| Gas connections | 1/4 inch NPT (F) |
| Hazardous area | ATEX/UKCA II 2 G and IECEx Ex db ib op is IIC T5 Gb; cQPSus Class I Div 1 Groups A–D T5 |
| Weight | Approximately 40 to 75 kg depending on configuration |
How to Order
To request a quotation for the Michell OptiPEAK TDL600, send Seven Star LLC your gas composition, H2S and CO2 levels, line pressure, required reporting units and whether the analyzer will sit in a shelter or outdoors. Download the datasheet from this page for engineering review, and contact our instrumentation team in Muscat for availability, delivery lead times and technical support anywhere in Oman and the GCC.
- Datasheet Michell OptiPEAK TDL600 Datasheet Download
Michell product families on this page
The Condumax II is an automatic hydrocarbon dew-point analyzer for natural gas. Several of its parts are listed separately: the CD2-SCR-002 hydrocarbon dew-point sensor cell, the CD2-WDC-002 water dew-point sensor assembly and the CD2-SX-WDC-002, which is the exchange version of that water dew-point sensor. The Easidew line is represented by the Easidew EA2 dew point transmitter and by the Easidew PRO I.S., an intrinsically safe moisture transmitter for hazardous areas. A ceramic impedance moisture sensor module is also listed, the sensing element behind these transmitters.Where Michell analyzers are used
Hydrocarbon and water dew point are contract quality parameters for natural gas, so the Condumax II is found at gas processing plants, pipeline entry points and custody transfer stations throughout the GCC. Easidew transmitters monitor dryers for instrument air and industrial gases, glove boxes, and dry gas feeds to processes that cannot tolerate water.Ordering Michell parts: what we need
For Condumax II parts send the analyzer serial number and the part code, such as CD2-SCR-002, and state if a new assembly or the exchange item is wanted. For Easidew transmitters we need the measuring span in dew point or ppm, the process connection thread, the output signal, the operating pressure, the gas and the area certification. A photo of the label on the old transmitter usually answers most of these in one go.Browse MICHELL Instruments products by category: Gas Analyzer Accessories, Gas Analyzer Systems.
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