Drilling for gas in the Arctic Circle – not an easy job. The climatic conditions are extremely harsh and -60° C is not uncommon. Russian energy conglomerate Gazprom was looking for a partner who could supply actuators and controllers that can withstand these extreme temperatures. The explosion-proof pneumatic actuator and control system GBVA from Festo fulfilled the demanding expectations straightaway and has been in use ever since along numerous pipelines in the far north.
Russian conglomerate Gazprom is the world’s largest natural gas producer and also supplies the German market. Gazprom intends to significantly increase production by 2020. To achieve that, new gas fields in far-off regions will be exploited under extreme climatic conditions. For example, a supply system for natural gas production, transport and export will be set up in Eastern Siberia and in the Far East.
While searching for an individually configurable solution and for gas valves that withstand the harshest of conditions, Gazprom approached Festo. We developed an actuator system specifically for Gazprom that operates reliably at ambient temperatures down to -60° C. The explosion-proof, pneumatic actuator and control system GBVA for ball valves has been in use along Russia’s natural gas pipelines since 2014. It has been so successful that many other system operators are now using it too.
The tougher the operating conditions, the stricter you have to be when selecting components for petrochemical systems. Extreme temperatures, explosive materials and distant operating locations place considerable demands on controller reliability for Gazprom. In a nutshell: everything has to be absolutely fail-safe. The next service station is too far away and the terrain is so rough that it would take days, if not weeks, to get replacement parts.
What's more, there is the cold. At temperatures down to -60° C it is not easy to change a valve, for example. The connectors are severely iced up and dangerous materials are flowing through the pipes. People can only withstand these temperatures when wearing special protective clothing that is centimetres thick. This makes it difficult for service technicians to move around easily. Valves are therefore only operated manually in absolute emergencies. And a controller that gets stuck should not be an issue. The valve technology specified by Gazprom should be able to effortlessly manage breakaway torques of up to 120,000 Nm.
Gazprom’s main requirement for our system was safety: sturdy inside and out, completely temperature resistant, long service life, efficient, saving on resources and manually operable in case of emergency. To ensure that maintenance and service are virtually unnecessary, mechanical damage, caused for example by water hammer, needed to be ruled out. And each valve had to be operated with no more pressure than was really needed for the application. In addition, our solution had to be configurable and adjustable to match the application conditions, such as for example pipeline size. And finally, Gazprom wanted to carry out tests on our valve-actuator unit under realistic conditions.
The GBVA (gas ball valve actuator) developed by Festo is a complete valve-actuator solution designed for controlling hazardous media in pipelines and operation at extreme temperatures. All the components are explosion protected (ATEX classification II 2 GD EEx d IIC T5). At the same time, the solution is easy to install, set up, control, maintain and to operate.
The control principle is based on quarter turn actuators DAPS with an explosion-proof design. Valves VSNZ make it possible to safely switch to the valve actuator in the local control mode. Safety guards prevent inadvertent switching – an important equipment feature for especially dangerous production locations. Pilot valves MGXDH are also used.
Connectors and piping are made of frost-proof stainless steel. The controller is integrated and thus protected. The valve actuator has plenty of torque (up to 120,000 Nm), making it perfect for heavy-duty operation. Controlled opening and closing times ensure gentle motion which is easy on the components and helps to prevent rebound impact and water hammer.
Permissible gas pressure at the system inlet is 413 bar. This is reduced to 2.5-8 bar with a pressure regulator, after which the gas is fed to the actuator chambers. Operation is thus also possible with a minimum pressure of 2.5 bar.
We equipped the GBVA/DAPS with a safety valve. It protects the pneumatic valve actuator from excessive pressure. The valve has a spring whose force counteracts the pressure of the operating equipment. The flow of the operating medium is guided underneath the valve seat.
We did everything we could during development of the GBVA/DAPS system so that the number of configurations and versions would be as large as possible. Depending on the size of the piping and the requirements, various cylinder sizes can be used in a solution: actuators DAPS in sizes DN 400 to DN 1200 in single-acting versions (with spring return) or double-acting valve actuators.
Since the locations where Gazprom would use the system were far apart, we took a great variety of climatic conditions into consideration during development: extremely low temperatures in the Arctic Circle, seismic activity in the Far East and abundant rain and snow in Central European Russia. Independent inspectors have validated the durability of the GBVA by carrying our numerous endurance tests on Gazprom’s test site.
Test runs carried out by Gazprom corroborated these results.
Festo fulfilled the customer’s requirements as specified and provided Gazprom with a solution that ensures reliable operation under extreme conditions and, at the same time, excellent flexibility in remote regions. As per the customer's request, we equipped the GBVA/DAPS with an air reservoir that is supplies the required amount of air for switching. This ensures reliable operation even when gas pressure in the pulse control line drops.
The low-maintenance pneumatic piston actuator works without delay and comes to an immediate standstill as soon as the operating command is deactivated or the end position is reached. This prevents the device from becoming damaged in the event of a malfunction. The characteristic torque curve of the rotary actuator is parabolic due to the yoke mechanism and is very close to the characteristic torque curve of the shut-off valves. This reduces the loads transferred from the valve actuator to the valve.
We designed the working chambers of the valve actuator so that they are only pressurised when switching. This significantly minimises the danger that a leak will develop, which is especially important in the case of natural gas. This solution increases the safety of the entire system and the actuator’s service life, because the valves are not continuously under pressure.
In the event that gas pressure is not sufficient to close or open the ball valve, an adjusting wheel can be used for emergency manual operation. It can be operated with a hydraulic cylinder which is activated by a manual hydraulic pump.
Compressed air, pulse gas or nitrogen can be used as an operating fluid for the pneumatic valve actuator. Pressure from the gas pipeline applied via a piping system can also be used as a source of operating power for the valve.
We have also developed a variant, based on double-acting valve actuators, capable of emergency closing or opening motion in the event that the electrical or compressed air supply should fail.
The pneumatic valve actuators included in the GBVA/DAPS series have been used successfully in the gas industry since 2006. Meanwhile, we have also implemented numerous projects of various sizes and designs. And we don't just work with the gas industry, but also with the petrochemical industry – refineries and terminals – and with operators of oil rigs.
We further developed our valve actuators GBVA for use in ESD systems (emergency shutdown): as soon as an emergency shutdown alarm occurs, the valve actuator moves to a safe position. The speed of the shutdown can be adjusted as required. NC and NO functions can be implemented with mechanical return springs or high-pressure receivers. We supply actuators GBVA/DAPS with partial stroke testing (PST) as an option. This function allows valves to be tested without a complete shutdown. The actuators and the controller comply with SIL 2/SIL 3. We can provide you with appropriate SIL certification for use in your ESD system on request.
We have also developed a version which autonomously supplies itself with power from a solar panel and/or a wind turbine, and stores the harvested energy in batteries. Charging is stabilised and controlled by a solar charge controller. Parameter data can be queried via remote access and visualised at an HMI (human machine interface). A handheld device is used for parameterisation. The shut-off valves (50 to 1200 Nm) can also be opened and closed remotely. The controller СРХ is used for control and data acquisition. A GSM modem transmits and receives the data. This system also boasts minimal maintenance requirements and reliable operation at low temperatures.