Most natural gas production and exploitation sites are considered to be hazardous area. This is certainly the case when it comes to Liquefied Petroleum Gases (LPG) sites. It is vital to avoid creating any areas, within the sites, in which the atmosphere contains flammable gas. The need to comply with stringent safety and environmental regulations and the associated cost and constraints associated with compliance, need to be factored in, when calculating a site’s profitability.
Natural gas is a natural resource present on the earth, which can vary in composition depending on the location of its extraction. In order to maximize the use and value of natural gas, it is necessary to control its composition. Even if it is composed mainly of methane, natural gas contains some traces of Sulphur compounds, which can affect its quality as well as having dramatic effects during its transportation (for example: corrosion of the pipes). Therefore, companies that work with natural gas need to control the level of Sulphur compound impurities, as well as adding specific Mercaptans to make it odourant and easily detectable in cases of leakage.
Chromatotec is the only manufacturer to provide Sulphur analyzers developed to require only 5 to 60 ml/min of zero air or nitrogen for operation including internal automation calibration. In addition MEDOR® instrumentation technology is some of the most sensitive that is capable of detecting without pre-concentration and without any convertor down to 1ppb of individual Sulphur compounds.
Other technologies require at least two gases to operate and/ or a convertor to convert Sulphur compounds into H2S or SO2 depending on the detector. It can be a problem for some operators to us hydrogen cylinders in hazardous areas; the risk of leaks prohibits their use. Convertors are not 100% efficient for all compounds and the efficiency decreases over time, which creates potentiality critical errors of measurement.
The energyMEDOR® allows the specification and measurement of sulfur compounds in different matrix (natural gas, LPG…). It’s capable of analyzing individual Sulphur compounds and Total Sulfur with direct measurement In addition the internal calibration stream (permeation tube installed into the instrument) is analysed at the end of every analysis, at a very low concentration level (ppb or ppm). Results are thus automatically validated. No external calibration cylinders are required for the operation and calibration. The energyMEDOR can detect Total Sulphur compounds thanks to its Sulphur Specific Detector (SSE).
The Odourisation of natural gas is an important application for which the energyMEDOR is a key product.
For safety reasons, natural gas is required to be readily detected by a person with a normal sense of smell. Therefore, the MEDOR® solution needs to be as sensitive as the human nose. Numerous performance tests where carried out analyzing of 8 Sulphur compounds and after 20 consecutive analysis where executed the energyMEDOR® detection limits for H2S was 0,1 ppm (0,1417 mg/m3) and for the energyMEDOR® ppb H2S it was 5 ppb (7,0 μg/m3) – Special option: 1 ppb and DMS it was 2 ppb (5,1 μg/m3).
Another application for the natural gas market is related to Integrity Monitoring. During the extraction of raw natural gas and following processing, midstream companies are required to track the level of H2S and TS (Total Sulphur = H2S + Total Organic Sulphur (TOS)). If the concentration measured exceeds the required level the midstream companies must shut down the gathering line until measurements are displaying the required concentration levels again. To complete this type of analysis, the sample is first loaded into a loop and then injected in an analytical column to separate the H2S from the other Sulphur Compounds.
To expand the applications of the MEDOR, a specific sampling module was developed that can inject extremely low volumes (from o.1 to 1 µL) into MEDOR autoGC for LPG analysis (Propane and butane), which is directly connected in the sampling module inlet. It is then vapourised and injected into the MEDOR directly. Other applications for heavier liquid hydrocarbons, like condensate or gasoline, are also available: as soon as they can be vapourised in the heated sampling module it is possible to analyze them with MEDOR®.