|Analytes||Odorants (i.e. mercaptans, thiophenes)|
|Detector||OMA-300 Process Analyzer|
|Process Stream||Natural gas|
|Zeroing Fluid||Ultrapure nitrogen|
|Calibration Fluid||Standard mixtures containing sulfides and odorants|
|Typical Range||0-10 ppm or 0.00-2.50 lbs/MMCF|
|Response Time||<15 seconds|
Odorants are added artificially to natural gas to allow for human leak detection. Local distribution companies (LDCs) employ numerous “sniffers” who judge odorant level in the natural gas product, while generating data from field reports, customer input, and modeling programs.
However, interstate pipelines span hundreds of miles that cross through various territories. Dispatching “sniffers” across vast distances is both time-consuming and cost-impactive. While “sniff testing” complies and satisfies the minimum criteria set forth in CFR, Title 49, Part 192.625, an on-line process analyzer would provide the same testing functionality with much richer quantitative data (one example: continuous trend data as opposed to discrete data points).
On-line odorant analysis allows the transmission companies to schedule the minimum required visits to perform sniffing, and optimize their odorant distribution system in real time. Secondary benefits allow them to optimize their pipeline performance by studying lag times, odorizer performance, fading effects, and other odorant issues.
The OMA-300 Process Analyzer is the ideal instrument for monitoring real-time odorant content. “Odorant” is comprised of a blend of different mercaptans and/or thiophenes, all of which show distinct absorbance features in the ultraviolet spectral range. The full-spectrum spectrophotometer is able to recognize these structures in a natural gas background and quantify their real-time concentration inside the pipeline.
Natural gas odorization has occurred since the late 1800’s, but did not come into law until the tragic New London School disaster in Texas which left more than 300 people dead. As a consequence, the Code of Federal Regulations, Title 49 Part 192.625 was enacted to ensure that where necessary, all pipelines contain a certain level of odorant. The federal code states that the sum of natural odorant and added odorant be readily detectable by a person with a normal sense of smell in air at one-fifth the lower explosive limit (LEL) of natural gas.
The spectra below demonstrate how the OMA visualizes the absorbance curves of various odorizing chemicals in a sample. Each odorant species has its own unique spectral footprint which the analyzer de-convolutes out of the total sample absorbance.
The OMA offers huge, distinct advantages that are unique to its full-spectrum UV methodology:
When supplying an OMA for odorant detection, the system is either a first investment in online odorant analysis, or it is used to replace a GC system. Users prefer the OMA for the following considerations:
Sniff testing is required by code, but only shows the operator a picture of their odorant concentration. With the potential for human error and bias and the cost to dispatch a “sniffer” across long distances, pipeline operators need secondary methods to supplement and back up their testing. On-line analysis allows the pipeline operator to (1) continuously monitor the odorant content in their pipeline; (2) identify fade due to new piping, contaminants, or reaction; and (3) troubleshoot odorizer performance for preventive action.
The OMA provides a completely automated and instantaneous measurement to give the pipeline operators deeper insight into their gas quality and operations.
The OMA pictured below measures H2S and RSH concentrations at a custody transfer station in New York state. The analyzer unit is installed on the external wall of the station, while the sample conditioner and flow cell are installed inside the station. This arrangement maximizes user safety as the analyzer is separated from the sampling point by a wall.
The specifications below represent performance of the OMA-300 Process Analyzer in a typical MEG purity application.
For technical details about the OMA-300 Process Analyzer, see the data sheet:
DS-001A: OMA-300 Process Analyzer
All performance specifications are subject to the assumption that the sample conditioning system and unit installation are approved by Applied Analytics. For any other arrangement, please inquire directly with Sales.
|Accuracy||Example ranges below; custom ranges available. Higher pressure may increase accuracy.|
|mercaptans/thiols||0-10 ppm: ±1 ppm
0-100 ppm: ±1% full scale or 1 ppm*
0-10,000 ppm: ±1% full scale
0-100%: ±1% full scale
|*Whichever is larger.|
Note: Subject to modifications. Specified product characteristics and technical data do not serve as guarantee declarations.
|OMA-300 Process Analyzer||Product page|
|OMA-300 Process Analyzer||Data sheet|
|OMA Odorant Analyzer||Product page|
|Advantage of Collateral Data||Technical Note|
|Multi-Component Analysis||Technical Note|