Real world wireless

By Alan Baird

Wireless for the process industries is here and is being used. In this article, Alan Baird, the PlantWeb Marketing Manager for Emerson Process Management in the Middle East and Africa describes just a few of the latest installations.

There has been a lot in the press over the past two or three years about wireless in the process environment.  As so often happens when a “game changing” technology is introduced there is a lot of media activity and potential users of the technology are bombarded with information. Wireless is no exception. No matter which process control magazines, journals or on-line portals you access you will not have been able to avoid reading about wireless technologies. All the articles agree that wireless is a good thing and that it will open up many new measurement points that just were not possible, or economically feasible before.

Where it may appear that some articles differ from others is in the way that they are advocating the technology should be applied. There isn’t a dispute in the fact that applying it across the whole plant brings enormous benefits, but the normally conservative process companies don’t want to have to make that investment up front, before they have tried and tested wireless and achieved some benefits.

Emerson Process Management’s Smart Wireless products enable either a top-down or bottom up model. You can begin at the plant level and work down to the field, or at the field and work up. At the field level, Wireless Field Networks are extremely low-powered to enable the use of battery-powered devices that operate for many years on the same battery. These solutions are also extremely secure and reliable. Emerson uses open standards such as 802.15.4 and WirelessHART™ to provide these solutions.

At the plant level, Wireless Plant Networks provide the high bandwidth, flexibility and expansion capabilities required by your business and operational applications. Of course, security and reliability are just as important for these applications as well. Emerson uses open standards such as 802.11 (“Wi-Fi”) to provide these solutions.

Smart Wireless allows you to start anywhere based on what your highest priority needs are. You’re not required to invest in an expensive wireless infrastructure throughout your facility to try out a simple monitoring application.

Emerson’s gateways, devices, access points and software use wireless communication standards and have gone through rigorous coexistence testing. This ensures that wherever you start in the architecture, you can seamlessly and easily expand later as your budget and confidence in the technology evolve.

For example, if additional process measurements would help you improve product quality or reduce energy usage we would recommend you build a sensor network at the field level starting with just a single gateway. If you need to provide mobile access to plant information then set up plant-level wireless access points so workers can get the information they need wherever they are. If both types of applications are important then implement them both at once, using the plant-through-field strength of the unified Smart Wireless architecture.

In short, flexibility and scalability mean you can start wherever it makes sense for you – without investing in more infrastructure than you need. This is certainly the experience of Emerson, which has applied wireless technology in numerous process industry applications across all world areas: applications such as well head monitoring at the BP Wytch Farm onshore oilfield.  Wytch Farm is Western Europe's largest onshore oilfield, comprising three separate oil reservoirs that lie under Poole Harbour and Poole Bay in Dorset, UK. These reservoirs are accessed via many different wells located around the oilfield and on islands in the bay.

As part of a drive to improve operations, BP wanted to increase the available information, improve worker efficiency, and remove the need for operator rounds. "Manual reading of pressure gauges on the wellhead was identified as one area we could improve," explained Chris Geen, BP Manager, "but we found that wired transmitters were simply too expensive due to the wiring infrastructure needed, so wireless is the perfect technology for this application."

Emerson’s Smart Wireless transmitters are enabling continuous monitoring of the wellhead pressure that indicates the condition of the well. Previously the pressure was measured by using gauges that were manually read once or twice a day. Continuous monitoring eliminates the need for daily visits to the wellhead and enables unusual readings to be identified earlier and action taken to investigate and rectify faults before they develop into serious problems.

The Smart Wireless self-organizing mesh technology is very reliable, and each measurement point has a redundant communication via two or three routes. With Smart Wireless each wireless device can act as a router for other nearby devices, passing messages along until they reach their destination. If there is an obstruction, transmissions are simply re-routed along the network until a clear path to the Smart Wireless Gateway is found.

All of this happens automatically, without any involvement by the user, providing redundant communication paths and better reliability than direct, line-of-sight communications between individual devices and a receiver. This self-organizing technology optimizes data reliability while minimizing power consumption. It also reduces the effort and infrastructure necessary to set up a successful wireless network.

The Smart Wireless network installed on one of the wellsites at Wytch Farm includes 40 wireless Rosemount® pressure transmitters. Two transmitters are mounted on each wellhead and a single Smart Wireless gateway, mounted outside the process area, connects the transmitters to the control system. Data is collated in a PI historian database with the information used for regular maintenance and safety reports.

Installation was quick and easy. Despite short access periods to the site, it took less than eight hours in total (spread over two days) to complete including removal of all the old gauges, replacing them with the Rosemount wireless transmitters and performing a three-point manual calibration check on every device. All devices were on-line within 30 minutes.

Despite cable trays, dense pipe work, and other metal obstructions shielding some of the transmitters from the gateway, each transmitter was powered up, the devices found the gateway and the mesh was established. As new devices were added, they quickly and easily joined the self-organising network. Signal strength and consistency during the operational period has been excellent.

"Wytch Farm has been a critical pilot project for BP to see if self-organizing wireless mesh technology would be suitable for other similar projects. Following the success of this installation, BP is planning to install Emerson Smart Wireless transmitters in similar applications on offshore platforms," said Geen.

StatoilHydro is another Oil & Gas producer that has applied Emerson’s Smart Wireless to monitoring wellhead annular pressure.  The company has also applied the technology on its Grane offshore platform stationed in the Norwegian Sea off the coast of Bergen, Norway, and is also using it for monitoring heat exchanger pressures. Emerson believes that the network on the Grane platform is the first offshore wireless installation in Europe.

"We had some concerns that this new technology would work reliably in the harsh environment of our offshore platform," said Geir Leon Vadheim, Instrument Lead, Grane Operations, StatoilHydro. "We also needed to address the issue of how we would integrate the data gathered by the wireless gateway into a third party system. As it turns out, the integration was easy and the performance of the Smart Wireless transmitters has exceeded our expectations."

The Smart Wireless network on the platform includes 22 wireless Rosemount pressure transmitters which replace traditional gauges. Ten pressure transmitters are mounted on a wellhead and used to measure annular pressure. A further twelve pressure transmitters monitor inlet pressure and pressure drop over the heat exchanger. Each transmitter relays data back to the operator consoles in the control room. Installation was quick and easy, typically taking around two hours to install compared with up to two days for a conventional wired unit.

"We are delighted with the performance of the Emerson Smart Wireless network in these challenging conditions," said Geir Leon Vadheim. "Following a short training program, our instrument engineers are very confident about adding more wireless devices to our installation as required.”

Following the success of this installation, StatoilHydro is planning to install Emerson Smart Wireless transmitters on other offshore platforms that it operates in the area.

Total Petrochemicals based in Carling, Saint Avold, France has applied Emerson’s Smart Wireless technology to provide valuable condition monitoring information. The introduction of wireless transmitters provides new temperature measurement data, enabling the company to calculate changes over time in wall thickness on a boiler that provides steam to a steam cracker. This will enable personnel to anticipate when it may need replacement.

By installing a wireless solution to connect the additional measurement points, Total Petrochemicals removed the need to install around 1 kilometre of new wiring. An additional benefit of the solution has been the reduction of movement of personnel into and around the at-risk areas.

Total Petrochemicals, part of the TOTAL group, produces a range of basic petrochemicals at the Carling site including ethylene, propylene, methane and styrene, as well as plastic consumer products including polyethylene and polystyrene. These products are produced by the process of steam cracking, whereby petroleum along with either gasoil or naphtha are mixed in a cracking oven with superheated steam at a temperature of 800 degrees C.

Total Petrochemicals wanted to better understand the condition of the boiler and anticipate when it might need to be replaced. To achieve this aim the company was keen to introduce a number of new temperature measurement points. By measuring the internal and external temperature of the boiler walls and identifying heat loss, it is possible to calculate the material's resistance and infer its thickness.

"Our plant is more than thirty years old," said Jerome Uszes, Electricity Control & Regulation Maintenance Manager, Total Petrochemicals. "With the rising cost of copper and aging existing wiring, finding alternative methods to carry data throughout the plant is becoming essential.  We believe in wireless technologies, and Emerson is a pioneer that is on the right track to offer a solution that meets our needs."

Eight Rosemount 648 wireless temperature transmitters were installed directly onto the exterior of a boiler drum situated 50 meters above the ground. An Emerson Smart Wireless Gateway was positioned on the roof of a technical building around 300 meters from the devices. Two additional temperature gauges were installed in strategic areas between the boiler and the gateway to provide sufficient coverage to the area and to enable supplementary measuring points to be added in the future as required.

Data from the wireless transmitters is passed from the gateway to a third-party DCS system via Modbus. From the control room, the operators have gained visibility of the thermal status of the boiler walls, allowing them to determine how the internal (process) and external (climatic) conditions impact the material's deterioration.

This noncritical monitoring of the boiler walls presented Total Petrochemicals with the perfect opportunity to evaluate Emerson's Smart Wireless technology on a large scale and in a real industrial environment. The application would also enable the company to determine the current limits of the wireless devices.

In all three examples the end user has experienced fast installation and commissioning, quick connection to the network despite tough working conditions, and the reliable transmission of valuable new data to help improve the process. These are the kind of successful applications of wireless that are enabling customers to gain the experience they need before applying the technology on a larger scale.

The products and knowledge are available and the value clear for starting wireless now. By picking an application - even a small one - you’ll join early movers enjoying the satisfaction of application improvements they could only imagine before wireless. And you’ll gain confidence and knowledge in the use of wireless, a technology set to make broad inroads industry-wide because of the significant improvements in efficiency and performance it delivers.

For more information go to www.emersonprocess.com/smartwireless or www.emersonprocessxperts.com/archives/2008/12/monitoring_gros.html