Explaining Teijin’s Customer Benefit Model for conveyor belts

The Customer Benefit Model (CBM) for conveyor belts developed by Teijin Aramid is a TÜV-certified software model. The model quantifies the potential energy savings under given conditions when a conveyor belt with a steel-cord carcass is replaced by an Twaron® aramid-fabric carcass. The CBM shows that a low environmental impact can go hand-in-hand with a sound business case, in terms of both Total Cost of Ownership (TCO) and Life-Cycle Analysis (LCA).

How the CBM was developed together with Professor Lodewijks

Teijin Aramid began developing the Customer Benefit Model in 2011 with the support of Professor Gabriel Lodewijks (then Professor of Transport Engineering & Logistics at Delft University of Technology), whose background is in industrial conveyor belts. At a conference in South Africa, Professor Lodewijks and Teijin Aramid Sales and Technical Manager Henk van de Ven discovered a shared interest in exploring the potential of aramid-reinforced conveyor belts, and enabling mining companies to make more informed decisions on their conveyor belt materials.

After writing a joint paper investigating the performance differences between aramid-reinforced and steel-reinforced conveyor belts, and the associated financial and environmental implications, Teijin Aramid found that gaining a return on investment from using aramid could take as little as three months.

Professor Lodewijks then began assisting Teijin Aramid in developing a first version of the Customer Benefit Model (CBM) with the additional help of TU Delft students. They undertook mathematical modeling and detailed calculations to quantify the benefits of aramid-reinforced conveyor belts in more detail. Teijin Aramid colleagues, supported by Ecomatters, a sustainability consultancy,  developed the model further to quantify the related costs and CO₂ emission savings.

The result of this collaboration is a model that closely reflects real-life operations. By comparing energy savings when using different reinforcement materials, it can help mining companies make the right decisions for their conveyor belts, adding significant value.

Input used for calculations

The input for quantifying these financial and environmental outcomes is the Energy Model; in turn, conveyor belt specifications provide the input for the Energy Model. These specifications include design parameters (e.g. belt speed and idler pitch), operational data (e.g. number of operational hours per day and percentage of time running fully loaded), and ambient data (e.g. ambient temperature and humidity).

From these belt specifications, the load exerted on the idler rolls by the belt and the bulk solid material on the belt can be calculated. The load on the rolls causes indentations in the belt’s bottom-cover rubber and an asymmetrical stress distribution between the rolls and the rubber. In turn, this asymmetry causes ‘indentation rolling resistance’ (IRR). IRR is responsible for about 65% of the overall friction in a horizontal conveyor belt and therefore plays a major role in calculations of its required power consumption. In long horizontal belts, more than half of the drive energy is lost due to IRR.

The power consumption of a belt conveyor using a conventional steel-cord belt can be calculated using the loads on the rolls and the IRR calculation procedure. Reduced energy consumption in the belt can be caused by lower carcass weights, uniform load distributions from using flat fabric versus steel cords, and thinner bottom-cover compounds. The effect of the weight can be quantified using the equations in DIN 22101 (where v is belt speed, η is drive efficiency, and F is Total Motional Resistance; f is the friction coefficient, m’G is belt mass, and m’L is mass of the load):

Required power:

P= Power of drive pulley (kW)
F= Total Motional Resistance (kN)
v= Belt speed (m/s)
η= Drive efficiency (assumed 0.9)

 

Total Motional Resistance:

 

 

 

 

 

 

 

 

L= Length (transport distance)
f = Friction coefficient (standard value: 0.02)
m’R = Mass of rollers (standard value: 30 kg/m)
m’G = Belt linear mass
m’L = Mass of load
θ = Inclination
H = Length * sinθ

Calculating CO₂ emission reductions

With its lower energy consumption compared to steel-reinforced belts, the aramid-belt concept also contributes to reducing CO₂ emissions. This is because the production of electricity generates vast amounts of carbon dioxide (CO₂) and particulate matter (PM10), with levels depending on the source used (coal or oil). The CBM considers the electricity mix in the country of operations and CO₂-eq intensity respectively, using figures derived from the latest IEA data and statistics (2018). In this way, it can be used to calculate CO₂ emission reductions (in tons and monetary terms) when switching from steel-cord carcass to aramid carcass.

Potential additional benefits of aramid

The CBM only takes the effects of the raw materials and use phase into account. However, there are additional potential benefits of using aramid, both financially and environmentally, in other parts of the lifecycle. For instance, the CBM assumes that the lifetime of a long-haul steel-cord belt is equal to that of an aramid-reinforced belt, because there is insufficient evidence otherwise in most cases. However, for long-haul conveyor belts used in highly corrosive environments, or where slitting frequently rips steel cord belts, there is evidence that aramid carcass improves belt lifetimes.

In Serra Grande mine (Brazil), using aramid carcass increased belt lifetimes by five times, while in the Baodian Mine (China) using aramid carcass halved maintenance requirements, improving the overall belt lifetime. In addition to these improved lifetimes, aramid carcass also causes fewer splices at the site of belt rolls, due to its lower thickness and transportation weight. While these benefits do not directly influence the model, they are worth considering when evaluating the potential of aramid-reinforced conveyor belts.

More information

For further information on the implications of using aramids in conveyor belts, please see: