VE Technology® Measurement of Trace Mercury and other Contaminants in Natural Gas

VE Technology® delivers patented products and unique, integrated sampling solutions dedicated to sampling perfection and ideal for challenging applications such as trace measurement of mercury and other contaminants in natural gas. Patented technology and new methods are necessary to achieve the level of accuracy required for effective process control and assure plant operability. This is critical in processing of natural gas for LNG export, as the presence of only trace quantities of Mercury can initiate and propagate irreversible damage of the aluminium heat exchangers, with potentially catastrophic effects. Safety of other plant equipment and personnel are also at risk when exposed to Mercury.

Measurement of trace levels of mercury in natural gas follows methods such as ASTM D-6350 and ISO 6978, and uses devices such as the gold-quartz trap shown.

Trace Mercury measurement is a complex task. Some of the challenges are not well known or understood:

1. Mercury in its gaseous form is arduous to measure, and the trace amounts that are typically found in natural gas are readily lost by adsorption processes onto surfaces it contacts.
2. Mercury also binds to particulates, and can become obscured inside droplets and aerosols. Filters or membranes that remove particles, droplets and aerosols, will also remove the mercury from the sample.
3. Mercury sorption is highly temperature dependent.
4. If the conditions are correct, previously adsorbed mercury from previous samples can desorb and enter into subsequent, ‘fresh’ sample.
5. Slight changes in ambient conditions or 'error margins' in your equipment can have a significant effect on your calculated concentration.

VE Technology utilises a number of basic principles to ensure that the sample retains its identity from probe tip to trap point. This is fundamental, and at the heart of the purpose-built products. Simply applying a coating to a portion of an all-purpose sampling system is not suitable, and will cost the user much more than it may save up front. It does not matter how accurate your analyser is, if the sample has lost its identity between pipeline and analysis, the readings are invalidated. The consequences of using incorrect data can be worse than receiving no data at all.

VE Technology accomplishes this by:

1. Patented aerodynamic probe tip that dynamically rejects particulates and droplets from entering the sample system – practically eliminating the need for filtration.
2. A true heat exchanger inside the VECU that protects every molecule from Joule Thomson cooling problems. ATEX and IECEx approved Zone 0.
3. A 2mm (0.08 inch) diameter sample pathway from probe tip to sorbent trap, minimal possible diameter changes in system.
4. ALL wetted surfaces electropolished and SilcoNert® treated, including the 0.4 µm filter.

All remaining control items, comprised by our Analyser Interface Module, are positioned in the fast loop or after the sorbent trap so they cannot contaminate the sample.

The entire system can be attached to the head of the probe, allowing easy access and operation. This significantly reduces installation costs, reduces the volume and response time of the sample system and ensures the sample is carefully protected throughout the entire system.

VE Technology® is exclusively licenced to Orbital Gas Systems, a CUI company; and sold worldwide through Orbital Global Solutions and its partners.