- Author: Neil James Slater
- Keywords: Oil & Gas
Senior Structural EngineerPhone: +33 6 80 40 70 16
Head of Fuel and Energy TransitionPhone: +31 26 3562423
Neil James Slater
Neil James Slater
Head of Media Relations and Events, DNV GL - Oil & GasPhone: +44 2038165702
The specific objective of this innovation challenge, which is part of GRTgaz’s Open Innovation program, was to provide a solution to reduce the environmental footprint of network maintenance activities for GRTgaz, requiring the evacuation of pipes while avoiding or minimizing burning or venting of trapped gas.
DNV GL’s 2017 Energy Transition Outlook highlights that gas will continue to play a key role alongside renewables in helping to meet future, lower-carbon, energy requirements. Increased interest in gas is expected as ‘oil’ majors reduce the carbon impact of their business portfolios. Globally the industry is looking for ways to minimize methane and direct CO2 emissions. In France, methane emissions represent more than 2,000 KT, mainly emitted by agriculture and the waste treatment sector, which together account for more than 90% of emissions related to human activity. In comparison, GRTgaz represents less than 1% (20 KT) of methane emissions.
GRTgaz is an international asset owner and is operator of the longest natural gas pipeline system in Europe. The company is committed to being exemplary in terms of environmental behavior and wishes to reduce the residual releases of natural gas to the atmosphere during the operation of its industrial equipment. For many years GRTgaz has been implementing and testing innovative methods to reduce greenhouse gases and emissions.The DNV GL solution will be another key methodology to address this.
DNV GL’s solution
For GRTgaz’ innovation challenge DNV GL proposed to introduce purging of pipelines with nitrogen as a method of evacuating pipeline segments complementary to the existing methods: gas boosting, and venting or flaring. Under suitable operational conditions purging with nitrogen has the potential to minimize methane and direct CO2-emissions in a safe and cost effective way compared to current methods.
To apply the new method successfully DNV GL would deliver clear guidelines on how to implement the nitrogen purging technique safely and effectively as well as providing a decision support tool to help select the best method to be applied in specific process conditions. The nitrogen purging option will be added to DNV GL’s existing decision tool Pipeline Evacuation Technology Selector (PETS), which is based on a value chain approach, including information on greenhouse gas emissions, operational costs and the complexity of the setup.
How it works
Purging pipelines with nitrogen involves the injection of nitrogen at one side of the pipeline, causing the trapped natural gas being displaced to a downstream pipeline segment. Upon detection of excess nitrogen by means of a continuous gas quality measurement system, the pipeline to be evacuated is blocked in. The nitrogen in the pipeline is then vented into the atmosphere.
Nitrogen purging as a complementary low emission technique for evacuating pipelines has the following advantages:
- Significant reduction of methane emissions during pipeline maintenance operations compared to the application of current technologies
- Relatively simple machinery to be deployed
- No visible flames or uncontrollable noise
- Less deployment of highly qualified staff required once tie-ins are established.
“Our involvement in these innovation challenges underpins our vision of having a global impact for a safe and sustainable future. As a next step the team aims to define a specific solution for GRTgaz to support them with implementation on their whole network. This nitrogen moving technique is only one element of a broad suite of tools, solutions and methods to help mid and downstream gas transmission operators reduce their CO2 footprints,” said Claire Fenouillet, Senior Consultant.
About DNV GL
Driven by our purpose of safeguarding life, property and the environment, DNV GL enables organizations to advance the safety and sustainability of their business. Operating in more than 100 countries, our professionals are dedicated to helping our customers in the maritime, oil and gas, energy and other industries to make the world safer, smarter and greener.
DNV GL is the technical advisor to the oil and gas industry. We bring a broader view to complex business and technology risks in global and local markets. Providing a neutral ground for industry cooperation, we create and share knowledge with our customers, setting standards for technology development and implementation. From project initiation to decommissioning, our independent experts enable companies to make the right choices for a safer, smarter and greener future.
GRTgaz is a French natural gas transmission system operator located in Bois-Colombes, France, and is a subsidiary of ENGIE created on 1 January 2005 in application of European directives on the European electricity and gas market. GRTgaz operates in the regulated energy sector with a board of directors made up of representatives of the French government and of personnel, independent directors and representatives of the ENGIE Group.
The transmission system consists of a network of high pressure gas pipelines; the main network comprises of 7,477km of pipeline and the regional network of 24,979km. 74% of the network is operated at a maximum pressure of 67.7 bars. Click here for more details.