November 12th, 2014
Saint-Gobain Seals has developed a new single stem sealing solution, which is targeted to lower fugitive emissions within ON/OFF valves in the oil and gas industry and create a more environmentally-friendly option for manufacturers who are dealing with increasingly stringent regulatory and legislative requirements that impact environmental health and safety. In studies conducted on oil and gas processing facilities, valves have been shown to be a major source of fugitive emissions; therefore, this piece of equipment poses the greatest opportunity for reducing fugitive emissions. By effectively containing these types of emissions, manufacturers not only benefit environmentally but also promote operating efficiency and safer, productive workplaces.
In order to meet future challenges for fugitive emissions, Saint-Gobain Seals began the process quite some time ago with the development of their low fugitive emission (LFE) seals. The objective was to develop a single stem sealing solution for ON/OFF valves that passed leakage tightness of Class BH and endurance class CO1 (500 cycles) from -50°C to 160°C according to the ISO 15848 quality standard. Since each valve can have up to four or more possible emissions centers: a bonnet gasket, two flange gaskets and a valve stem (which is the main emission source for valves), their main focus became concentrated on engineering a solution with the valve stem.
To achieve this, Saint-Gobain Seals invested in a test rig that solely operated according to the ISO 15848-1 criteria. Their first step was to study the impact of jacket and spring designs on LFE leakage performance. They also selected materials that optimized leakage performance by limitation of permeation. The next step was to optimize the design of their V-packing component to improve leakage performance with the help of FEA analysis. Based on testing data and past experience and knowledge, they developed different design concepts using their well-established and proven OmniSeal® spring-energized product to pass the specification. To validate the new OmniSeal® designs, Saint-Gobain Seals Research & Development used helium as test fluid while the measurement was conducted in a close chamber under vacuum with a mass spectrometer for detection to give the highest accuracy.
Compared to other sealing solutions for low fugitive emissions such as compression packings, the OmniSeal® spring-energized seal offers the following benefits:
In order to reach the best performance, it is also important to follow specific installation guidelines. Polymer spring-energized seals must be handled with extreme care and must not be unpacked and put down on dirty surfaces before installation. All mating surfaces must be clean and without any scratches and corrosion, and the roughness of sealing surfaces must comply with OEM recommendations.
Saint-Gobain Seals has been successful in providing sealing and polymer solutions in other areas of the oil and gas industry, having their OmniSeal® seals certified for the axial control valves portion of the first subsea gas compression system that will go on stream at a water depth of 3,000m in Norway in 2015, frequent use of their OmniSeal® RACO™ seal for offshore LNG (liquefied natural gas) transfer in dynamic conditions, and selection of their Meldin® 5000 series product for packing kit backup rings in a hydraulic drilling jar (down hole drilling application).
They contributed an article in Valve World magazine (November 2014 issue) with a more in-depth discussion on their new single-stem sealing solution. They will launch this new product at Valve World 2014 (Hall 3, Booth B88), which is being held from December 2 to 4, 2014, in Düsseldorf, Germany.