Controlling Clinker Level in Lime with Radar Sensors

The VEGAPULS 6X radar sensor for bulk solids level measurement mounts at an extreme angle on the Lhoist clinker cooler. Image Credit: VEGA

Lime plays a more important part in each of our lives than we may think. A number of everyday products contain the mineral, including glass and sugar, and it is used to produce many frequently used materials, such as plastics and metals. It’s lucky, therefore, that companies such as Lhoist North America exist, to provide us with lime and other minerals on which we depend.

One member of the Lhoist group is Lhoist North America. They are a major supplier of limestone, clay, and lime products for industrial use in paper mills, power plants, steel mills, metal mines, chemical plants, and others across Canada and the United States.

One of these sites is a lime producing site in Alabama, which also produces other construction materials. On this site, in vessels which are designed to cool down hot material, VEGAPULS 6X through-air radar delivers accurate and consistent level measurements in difficult process conditions.

Application Overview: Clinker Cooler

In the production of cementitious materials, the clinker cooler is an application of great importance. Limestone is heated at the Lhoist facility inside a rotary kiln, at temperatures in excess of 2,000° F. Clinker is the name of the hot, fused material produced, which is transported out of the kiln to a cooler. Before it can be stored, clinker needs to be cooled using a continuous stream of air.

In order to maintain process efficiency and protect against overfill conditions, level measurement inside the cooler is vital. As a consequence of the inhospitable conditions inside the cooler, professionals in the mining industry use radiometric instruments for level measurement in this application. Although they give measurements which are reliable, there are challenges involved in the use of radiometric detectors.

An exceptional radar level sensor is required in order to deal with the difficult challenges presented by the clinker coolers found on the Lhoist site. Mounting represents one such challenge.

A four-foot standpipe is attached to each cooler, and on this a sensor is mounted in order to avoid the extreme heat of the vessel. A narrow path through to the clinker is created by the pipe.

This path isn’t wide enough for the majority of bulk solids’ radar sensors, because the excessive noise is created in the measurement by contact between the radar beam and the pipe walls. The pipe is additionally mounted at an extreme angle, aiming at the opposite wall of the cooler, near to the bottom.

VEGAPULS 6X: An Innovative Solution

Lhoist followed the advice of local representative BBP Sales and VEGA advisors in commissioning VEGAPULS 6X with a 4” process connection for installation on each of the clinker cooler standpipes.

The VEGAPULS 6X is a non-contact radar sensor for the level measurement of bulk solids. It operates with an 80 GHz transmission frequency. A beam thin enough to travel the pipe’s narrow path without making contact with its walls is emitted by this high frequency radar sensor. This avoids the creation of excessive signal noise. Depending on the size of the antenna, beam angles vary; on this occasion, a 4° beam was emitted by the radar sensor.

All three of the parties involved – BBP, VEGA Americas, and Lhoist – were aware that extreme heat could melt through-air radar sensors. In order to avoid this unwanted scenario and maintain level measurement in the clinkers, hot air was kept away from the sensors via the inclusion of air purges. The sensors have been operating reliably since the installation of these. An unobstructed signal without any false echoes is received by users, who can measure product up to as close as three feet away from the sensor.

Exceptionally difficult challenges were presented by Lhoist’s clinker coolers, which could only be beaten with an equally exceptional radar level sensor. With the aid of their partners at VEGA Americas and BBP Sales, the supplier of limestone and lime found everything it required in the VEGAPULS 6X.

Watch this video for more information on the superior focus of the VEGAPULS 6X.

This information has been sourced, reviewed and adapted from materials provided by VEGA Grieshaber KG.

For more information on this source, please visit VEGA Grieshaber KG.