Driving more sustainable operations requires a look at many areas to find ways to optimize and reduce emissions. One place to focus is the valves and the actuators that drive their movement. In a CHEManager International article, Innovative and Disruptive Automated Valve Package offers Decarbonization Solution, Emerson’s Knut Riegel shares how advancements in valve actuation technology fitted on isolation and shutoff valves have enabled reduced emissions. Knut opens by highlighting the challenges in most of the process industries.
Energy-intensive industries – such as petrochemical plants and oil & gas pipelines – are currently in focus when it comes to achieving sustainability goals (“Net-Zero”). One of these goals is to limit the ecological footprint (i.e. the emissions that increase the greenhouse effect and cause global warming) and thus, achieve decarbonization.
Emissions are a focus area to improve sustainability.
The oil and gas pipelines alone, which transport the product to refineries for further processing, release almost 50 tons of emissions into the atmosphere per year, and the chemical process industry an additional 25 tons per year. Methane, accounting for 6% of anthropic greenhouse emissions, is a major component of crude oil. This is up to 30 times more harmful than carbon dioxide.
Valves are one source to address.
Due to the type of valves and their associated valve actuator, unintentional fugitive emissions can escape into the atmosphere. Valve sealants that have become brittle or leaks in the packing of the industrial valve can also cause emissions to escape.
Due to the type of valves and their associated valve actuator, unintentional fugitive emissions can escape into the atmosphere.
Valve sealants that have become brittle or leaks in the packing of the industrial valve can also cause emissions to escape.
Knut highlights the sources of plant emission leaks and the significant role valves play. Valves account for around 60% of fugitive emissions.
Across the oil and gas value chain and especially:
…in midstream applications, 90° shut-off valves are used almost exclusively due to their design-related advantages, such as a very low leakage rate, high-pressure rating, and nominal size with a simultaneously wide temperature range. Two types have been successfully established for decades: Butterfly valves and ball valves.
AEV C-Ball valve
He describes the AEV C-ball valve, which helps significantly reduce emissions. This double eccentric valve is similar in principle to a conventional ball valve but with a half ball that makes a “C” shape. This C-shaped ball rotates on two planes of motion with energy from the stem to close and seal against a fixed seat.
The unrestricted bi-directional valve requires no venting, which allows optimized pipe routing with fewer shut-off valves at 30% less weight compared to traditional rigid top-entry ball valves. These specially designed and tested sealings eliminate or minimize any emission leaks.
In oil & gas pipeline high-torque actuation applications, two types of actuators fit the application— Gas motors and fluid-powered Gas Hydraulic Valve Operators . Gas motor actuators have methane emissions.
Gas-over-oil fluid-powered actuators:
…offer the advantage that no separate supply is required. The actuators are used in pipelines that usually run hundreds of kilometers through underdeveloped areas where no low-pressure pneumatic instrument air or high-pressure hydraulic supply lines are available. The pipeline itself is under high pressure and thus provides a “dedicated” source of supply for intrinsically fluid-controlled systems (gas-over-oil). Unfortunately, emission discharges are not 100% avoidable here either.
Depending on pressure rating requirements, other options include electric, electro-hydraulic, and pure DC electric valve actuators.
With the electro-hydraulic alternative, gas recovery takes place thanks to the replacement of the existing pneumatic and/or hydraulic components. These are additionally automated with “smart” accessories like Digital Valve Controllers, i.e., electro-pneumatic components that lead to less methane ventilation and reduced temporary medium leakage.
Knut points to the combination of best matching of superior valve and actuation technology that minimizes emissions.
A completely smart emission-controlled solution is ensured by the adaption of an ECAT system (Emissions Controlled Actuation Technology), in conjunction with the innovative AEV C-ball valve In principle, this actuator system is similar in design to an own-medium operated valve control system and therefore offers all the above-mentioned full advantages of the intrinsically fluid-operated actuator, especially for applications in ecologically sensitive areas. In addition, it scores points in direct comparison to conventional drive technology, especially in the high-pressure range.
Read the article for more on emissions of the various pipeline valve actuation technologies and valve types, and visit the Valves, Actuators & Regulators section on Emerson.com to improve your overall operational sustainability initiatives.
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