Natural Gas is an important cornerstone of the energy supply. Its total share of primary energy consumption in Germany in 2004 was 22.4 %, earning 2nd place directly behind oil. Used commonly for both heat and fuel, burning natural gas produces less CO2, which is one reason why the market share for natural gas in the future is predicted to increase sharply.
There is currently growing demand for alternative sources of energy that are environmental and climate-friendly as well as economical to extract and produce. The history of natural gas as a primary energy source is relatively young, gaining prominence first in the mid 1960`s with the discovery of a large natural gas field on the European continent. In just 30 years, the market share of natural gas in primary energy consumption climbed to over 20 percent. But what is natural gas really? Natural gas is a product of nature that includes all gaseous hydrocarbon components that originate from the earth and are combustible. At least 85 percent of the volume consists of methane and up to 10 percent from nitrogen and carbon dioxide. Natural gas is stored in underground caverns and porous rock formations. Based on current yearly demand and considering the technically intensive methods necessary to procure it, the supply of natural gas is estimated to be sufficient for the next 170 years.
In addition to an underground network of pipelines, the transport of natural gas increasingly employs the use of sea vessels. A condition to make this possible is the application of technical procedures to reduce the volume of the gas. For LNG (Liquefied Natural Gas) this takes place by cooling the gas to minus 162 degrees Celsius. Through this process the natural gas takes on a fluid form and can be transported with specially outfitted ships. A further option is compression. The resulting CNG (Compressed Natural Gas) is methane in a gaseous state which is pressurized to between 50 and 150 bar. CNG is used primarily as fuel for automobiles powered by natural gas. Natural gas motors employ an extremely ecological form of propulsion technology. In comparison to petrol engines, natural gas produces 25 percent less CO2, making it the cleanest burning of all known fossil fuels. A growth rate in the area of circa 40 percent further reflects the importance of this development. World-wide, 4.5 million natural gas vehicles are already in use.
The challenge faced by the engineers at Emco Wheaton was to create a CNG marine loading arm that could be operated at pressures up to 150 bar with a safety feature allowing emergency release of the loading arm from the ship in the event of an emergency. In addition to the high pressure, the loading arm had to be capable of employment under the various conditions existing on board a re-gasification vessel. The heavy mechanical load and the ability to withstand uneven movement on the sea also had to be considered.
During the development process, Emco Wheaton carried out extensive computer based simulations as well as field tests to safeguard that the delivered unit would meet all safety regulations for the transport of CNG. All sub-components as well as the entire unit were intensively tested and were certified by Bureau Veritas.
The result, after 12 months of research, development and testing, was a 12 inch marine loading arm with structural components capable of meeting the extreme loads and conditions. A hydraulic quick coupling system was developed specifically for use in high pressure conditions. This system includes a quick coupler with connector claws that can fully retract beyond the connecting flange pane which can withstand the resulting high pressure and guarantee a safe connection. The loading arm can adapt to the movement of the ship within a given working area and is equipped with a newly developed emergency system that allows the arm to be quickly and safely disconnected from the ship if necessary.
The CNG marine loading arm is first being employed on the eastern coast of England in the port of Teesside Middlesbrough. With a daily capacity of 11.3 million cubic meters, the facility in Teesside covers circa 3 percent of England’s daily peak demand for natural gas. Thanks to the CNG marine loading arm, the gas can be directly transferred from the regas tanker into the national gas grid of Great Britain, avoiding the need to construct additional storage tanks and regas facilities on land.
With the CNG marine loading arm, Emco Wheaton not only delivered the given requirements, but exceeded them. As well as assisting the needs of the client, Emco Wheaton also provided support to many other project participants during the entire project, encompassing the successful planning, erection and commissioning of a prototypical installation.
This is the first of many projects of this type that are at various planning/investment approval phases and will create a long-term revenue stream for the business.