Valve automation delivers centralised monitoring and control to pipeline network
28/02/2011A programme of valve motorisation is a central feature of an extensive automation project that will obtain, store and process data in real time from a network of liquid hydrocarbon product pipelines in Latin America.
The project is installing a SCADA control system for the integration, monitoring and control of valves at more than 100 refining product, storage and injection sites on over 2500 kilometres of pipeline. Unlike oil pipelines that transport only crude oil, product pipelines such as these transport a range of liquid hydrocarbons.
The project includes the necessity to replace manual gearboxes with actuators on over one hundred mostly remotely sited valves. The actuator specification demanded a self-contained design, suitable for remote, exposed locations with only limited electric power availability. Further constraints of the specification included:
Self-locking drive mechanism to prevent valve positional drifting.
Adjustable speed control.
Low gas consumption.
Operation available from stored gas energy source.
Compact overall dimensions.
After reviewing the available technologies, Rotork’s engineering department has been able to select the best solution with a standard product from the company’s fluid power actuation portfolio.
The Twin Power is a self-contained multi-turn actuator, operated either pneumatically or hydraulically. The mechanical design is based on either a bevel gearbox for linear valves or a worm gearbox for quarter-turn valves. The actuators on this project are designed to operate from stored nitrogen tanks, sized for three valve cycles. Three operating modes are available:
Remote control via a solenoid valve and stored nitrogen gas.
Local control via manual pushbuttons and stored nitrogen gas.
Local manual operation via a hand crank.
The electrical supply requirement is 12Vdc or 24Vdc, facilitating solar/wind powered renewable energy battery operation in remote locations. The actuators are supplied with an environmentally protected stainless steel control cabinet containing Local/Remote/Manual selectors, Open/Close pushbuttons, solenoid valves, manifold blocks, flow control valves, limit switches and electrical terminals.
The new Rotork actuators and those already installed on the pipeline network will provide a vital rôle in the operation of the new SCADA system, which will yield greater security in the operation of facilities and mitigate risks for personnel, local communities and the environment.
The system is designed to centralise the monitoring of all operational variables, including pressure, temperature and fluid composition, all of which are significant factors in the transport, storage and distribution of liquid hydrocarbons.
In addition to increasing the security of operations, the integration of product storage field equipment is expected to improve efficiency and reliability by optimising the management of operational data and information. The SCADA system will make it possible to obtain, store and process data from geographically dispersed areas, in real time, to ensure the timely delivery of crude oil required by refining centres and the refined products needed to meet the demands of distribution and marketing centres. This would not be possible without the ability of self-contained actuators to operate valves in remote locations and communicate their activity and status to the centralised control system.