SELECTING THE RIGHT OVERLAND CONVEYING TECHNOLOGY TO IMPROVE CEMENT PLANT OPERATIONAL EFFICIENCY

Cement plant operators face economic pressure to reduce operating costs and environmental pressure to reduce emissions. While trucks and trains have been the default solution for transporting limestone from the quarry to the plant, modern overland conveying technology provides a viable alternative. How can cement plant operators select the right overland conveying technology for their bulk materials transfer?

By Brian Giese 

 

Trucks and trains have long been the traditional solutions for bulk materials transportation for cement plant operators. Trains have the advantage of energy efficiency, but they require significant capital investment and are usually only deployed over very long distances. Trains have no route flexibility and do not provide continuous transport.

Truck fleets offer a flexible and scalable approach, which can even be outsourced entirely. However, truck transportation models also have limitations. Diesel-driven trucks have high operational costs due to fuel consumption and regular maintenance requirements. Cement plant operators must also consider the cost of controlling dust when using trucks.

At the same time, trucks have a negative environmental impact. Diesel engines contribute to carbon emissions and generate noise. In addition, material spillage during loading and unloading or en route to the destination contaminates the environment. In contrast, modern cement industry solutions like overland belt conveyors have several advantages, such as the elimination of intermediate transfer points, lower operating costs and lower emissions.

What factors affect the choice of conveying technology?

A comparison of trucking vs conveying shows that modern conveyor technology offers a viable alternative to trucks for cement plant material transfer, given its ability to improve the plant’s operational efficiency. With this in mind, plant operators should consider the specific parameters of their application so that they can select the best conveying technology for their needs. Factors that may affect this choice include:

  • The required mass of material to transfer in tonnes per hour.
  • The characteristics of the terrain, boundary or property lines, areas with restricted access, topography, road or water crossings, and other influencing factors.
  • The nature of the material, especially the presence of large lumps, plus any potential environmental protection needed for either the material itself or the surrounding area.

What are your overland conveying technology options?

There are three main single-flight conveying solutions for cement plant materials transfer, each with advantages and disadvantages.

1. Curved TROUGH BELT CONVEYOR

A curved trough belt conveyor, or troughed belt conveyor is the most common overland conveying solution for cement plants, covering 90% of applications. It has a belt shaped like a trough and can achieve transfer rates up to 14,000 tph with single belt lengths up to 15 km. Curved trough conveyors can handle large lump sizes and have the capacity to generate power on downhill sections. On the other hand, incline and decline rates are limited to a maximum of 20 degrees and horizontal curves require long radii. Carry and return strands are not enclosed. However, a belt turning station at the destination point ensures that the dirty side of the belt faces upwards on the return, which keeps return idlers clean and prevents dust from falling off the belt.

2. PIPE CONVEYOR

A pipe conveyor has a belt shaped like a tube, giving rise to its alternative name of tube conveyor. This solution can achieve transfer rates up to 6,000 tph with single belt lengths up to 7 km. Pipe conveyors can handle steep incline and decline rates of up to 30 degrees. They can also accommodate tight horizontal curves, which makes them ideal for in-plant applications. The versatility of pipe conveyors makes them suitable for several types of material, including, alternative fuels, cement or clinker, ores, limestone and gravel. Both carry and return pipe conveyors are enclosed, which protects the environment from spillage and protects the material from the effects of sun, wind, and rain. Pipe conveyors are best suited for bulk materials with small to medium particle size.

3. U-BELT CONVEYOR

A U-belt conveyor is a combination of the trough and pipe conveyor. The belt is shaped in a U on the carry side and a pipe on the return side. U-belt conveyors have a maximum transfer rate of 10,000 tph. These conveyors can handle tight horizontal curves similar to pipe conveyors, but their incline and decline rate limits are slightly lower than pipe conveyors at 25 degrees. U-belt conveyors are ideally suited for applications without space for a trough belt system or where the material flow is too high for pipe conveyors. This solution can handle a variety of material sizes, including large particles. The carry side of a u-belt conveyor can be equipped with a cover, though the return side is fully enclosed, helping to eliminate spillage on the return.

Takeaway

The cement industry is under increasing global pressure to reduce operating costs and minimise environmental impacts for better operational efficiency. Limestone transportation using trucks is one key contributor to costs and emissions that cement plant operators can target.

Single-flight conveyors provide plant operators with an opportunity to contribute to decarbonisation and the creation of a circular economy by reducing truck use and recovering energy on downhill conveying sections. These modern cement technologies positively impact cost per use across their lifetime.
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