Total tunes into wireless condition monitoring at French site

Carling Saint Avold, France - Total Petrochemicals, part of the TOTAL group, is employing wireless technology - Emerson Process Management’s Smart Wireless system - for condition monitoring at its plant in Carling Saint Avold. The introduction is providing 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.

The Carling site produces a range of basic petrochemicals 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 gas oil or naphtha are mixed in a cracking oven with superheated steam at a temperature of 800ºC.

Total engineers wanted to to introduce new temperature measurement points to help them better understand the condition of the boiler and anticipate when it might need to be replaced. 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 30 years old,” said Jerome Uszes, electricity control & regulation maintenance manager at Total Petrochemicals. “With the rising cost of copper and ageing existing wiring - corrosion, infiltration, armature degradation etc. - finding alternative methods to carry data throughout the plant is becoming essential.”

This non critical monitoring of the boiler walls presented Total Petrochemicals with the opportunity to evaluate 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 and to direct future development of the technology.

Eight Rosemount 648 wireless temperature transmitters were installed directly onto the exterior of a boiler drum situated 50 metres above the ground. A wireless gateway was positioned on the roof of a technical building around 300m 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 on the material’s deterioration.

An additional wireless device, a Rosemount 3051S pressure transmitter, is providing redundancy for an existing wired device that provides a critical measurement in the plant. This transmitter also reinforces the wireless mesh and provides an additional path back to the gateway.

Use of wireless to connect the additional measurement points, enabled the petrochemicals major to eliminate the need to install around 1km of new wiring, said Emerson. Another benefit, it added, has been the reduction of movement of personnel into and around the at-risk areas.

“We eagerly await the availability of open standard WirelessHART products that guarantee interoperability. Once these are available we can look to use Emerson’s wireless technology for control applications in the plant,” concluded Jean-Michel Glad, control & regulation reliability engineer at Total Petrochemicals.