Page 50 - ITA Journal 3-2018

Technical Papers
Valve World Expo
Solid as a rock: The importance of gas storage
plants is growing. Facilities require resistant
valves.
Renewables are all the trend in some European countries. Depend- ing on the weather, however, they can be real drama queens. To prevent bottlenecks, grids are increasingly being fed with elec- tricity produced by gas. As such, gas storage is becoming an impor- tant issue. For they can also store excess energy, and feed it back in when consumption rises. In unstable times, such storage facil- ities are as solid as a rock.
It is indisputable that demand for natural gas is rising in Europe – especially during transition phase away from nuclear power and CO2-intensive forms of energy. According to the Arbeitsgemein- schaft Energiebilanzen (AG Ener- giebilanzen, Working Group on Energy Balances) natural gas con- sumption in Germany, for example, had a share of 20.9 percent in the total energy mix, by 2016 it had risen to 22.6 percent. With a growth of 9.5 percent, gas belongs to the big winners in primary energy consumption, while renewables came in second with 2.8 percent.
EU to import more gas
Gas supply is an important topic in nearly the whole of Europe. “In the future, the European Union will have to import more and more natural gas to meet demand in the home market. Therefore demand for additional natural gas tank farms is growing,” explain the companies Astora and EWE, project partners of the Jemgum natural gas storage cavern.
Gas storage will play a central role in securing the energy system transformation project, “as it is the only way to chemically store excess energy from renewables – wind and sun – in the form of hydrogen or green methane and secure the uctuating balance,” states Maurice Walter, head of sales and services, Hartmann Valves. Or, in other words: if the wind isn’t blowing and the sun isn’t shining, gas compensates the power uctuations of renew- ables. “Storage ensures stable levels of availability and exible usability of the energy source,” emphasises Astora.
Store gas in summer
The German storage facility Wolfersberg makes an important contribution. In summertime, excess gas imports are stored in the storage facility located in Upper Bavaria, and in wintertime it is fed into the gas grid. Wolfers- berg has a maximum storage capacity of 140,000 Nm3/h, a maximum withdrawal capacity of 240.000 Nm3/h and a working gas capacity of 365.000.000 Nm3. Capacities, that actively supply energy to the metropolis Munich.
However, old shut-off valves had to be replaced in the natural gas storage facility Wolfersberg, which had been put into opera- tion in 1973. In order to ensure an extremely high level of safety and maximal availability, Hartmann Valves developed highly compact twin ball valves, which are not only extremely gas-tight, but also
solved the problem of limited space. They ful l an important duty for the facility: “We must be able to isolate every part of the plant which needs to be repaired or maintained. Two shut-off valves with the possibility to bleed off pressure in between serve as iso- lation. Thus, we ensure 100% that no gas enters the area concerned,” states operations manager Markus Schuster, DEA.
No problems for renewing isolation section
Most of the Hartmann ball valves installed are single ball valves. As safety requirements were espe- cially high, 40 twin ball valves were installed. They offer a double barrier and two distinctly inde- pendent isolating mechanisms in one body. The easy to install, zero-bubble-tight system provides twice the level of safety, and it saves space, as the company states.
An extra compact special design of the twin ball valve was developed when an old isolation section in the main injection line had to be renewed. It consisted of a welded and anged ball valve. Exchang- ing the welded valve would have resulted in a long downtime. Hart- mann Valves therefore engineered a twin ball valve DN 250 PN 250 version, with the same length of the original standard valve. After a successful trial period, further compact twin ball valves sharing the same dimension were also installed in the gas drying facil- ity. The extreme shortening of the
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