computers & controls
23
Prior to the regulation being introduced, Lenzing
was already monitoring the water temperatures
manually involving daily visits to the river. However,
to meet the environmental regulation there was a need
to improve the reliability of the results and for these
measurements to be easily stored and be made readily
available for inspection. By implementing a solution
that enabled online measurements, Lenzing Fibres was
presented with an opportunity to reduce operations
costs by eliminating the number of trips to the river
and to streamline the reporting.
The water temperature is transmitted wirelessly
via Emerson’s Rosemount wireless temperature
transmitter, to a Smart Wireless gateway. The gateway
is on an external wall of the pump station control room,
200 metres away (Fig. 1). A second wireless transmitter
is installed where water is returned to the river, and a
Fig. 2. The eight wireless transmitters send pressure data back to
third transmitter is 200 metres downstream where it
the INEOS control system where the condition of the filters can be
measures the temperature of the remixed water after
constantly monitored.
the return point. A fourth transmitter is currently used
Image courtesy of Emerson Process Management.
as a weather station and is situated by a nearby lake
that is used as a cooling water reserve. This device A liquid column (u-tube) was installed across the
acts as a repeater and provides additional paths for the filter, indicating the differential pressure. An increase
self-organising network, ensuring the highest possible in the pressure suggests that the filters are blocking.
communication reliability. Identifying a blocked filter did, however depend on
Emerson’s AMS Suite: Intelligent Device Manager the operator making his rounds at the moment the
is used to manage the new Smart Wireless devices, blockage was becoming noticeable.
enabling the technicians to configure the devices, run An automated alternative to the operator’s visual
diagnostic checks and monitor alarms and alerts. AMS inspection was to measure the differential pressure
Suite is also used to manage and store calibration across the filter. An increase in differential pressure
information. The Smart Wireless network is integrated above a pre-determined point would indicate that
into Lenzing Fibres’ existing control system and the the filter is becoming blocked. However, because of
temperature information is stored in a data historian to the location of the filters, connecting the required
meet environmental regulations. measurement points back to the control system using a
Emerson’s self-organising technology delivers high wired solution was not feasible.
communications reliability and makes addition of INEOS looked at a number of wireless technologies
more measurement devices easy. Each wireless device for this task, but found that line-of-sight solutions
can act as a router for other nearby devices, passing could not provide the reliability of connection or
messages along until they reach their destination. the robustness they required. The transmitters are
If there is an obstruction, transmissions are simply positioned in a dense working environment with many
re-routed along the network until a clear path to the metal obstructions that can cause interference. There is
Smart Wireless gateway is found. As conditions change also moving equipment that could cause temporary loss
the wireless network simply reorganises and finds a way of signal for line-of-sight wireless solutions.
to get its signals through. INEOS installed Emerson’s Smart Wireless solution.
Installation of the wireless temperature transmitters Eight Rosemount 3051S DP wireless transmitters were
in Emerson’s self-organising wireless network enables installed as well as a single Emerson Smart Wireless
the company to meet local government regulations gateway. The eight wireless transmitters send the
related to the temperature of water discharged into pressure data back to the INEOS control system where
rivers and watercourses. the condition of the filters can be monitored. The
A similar solution also enables INEOS to monitor transmitters are positioned up to 150 metres from the
filters within polyethylene pellet transportation tubes, gateway (Fig. 2).
blockages of whose filters can lead to production With the self-organising technology, each wireless
downtime at its plant in Cologne, Germany. The pellets device can act as a router for nearby devices,
are ‘blown’ through the transportation tubes using passing messages until they reach their destination.
compressed air. The incoming air is filtered to prevent This happens automatically, providing redundant
any pollution of final product. The filters become communication paths and better reliability than direct,
blocked over time and lose their efficiency, which in line-of-sight communications between individual
turn affects the quality of the end product. devices and a receiver. v
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