DuPont™ Kevlar® fiber is helping to create solutions for lighter, stronger and longer-lasting conveyor belts
Conveyor Belt is one of the most critical elements of any bulk material handling operation, as seen in a steel plant. Large volume of metallurgical coke (Met Coke), a key ingredient in the manufacture of steel, needs to be produced, handled and transported to steel manufacturing location using conveyor belts. However, production of Met Coke is done under extremely challenging thermal conditions and transport of hot met coke poses significant challenge to the conveying system.
High temperature of the met coke causes frequent stoppages of the belt resulting in loss of productivity and high maintenance costs. This problem is not limited to the production of metallurgical grade coke but also for power plant grade coke as well. One of the largest metallurgical grade coke manufacturer approached Oriental Rubber Industries advising them to help in finding solution to lower belt life, high belt maintenance, which are adversely affecting their productivity and operational efficiency.
Incumbent reinforcement material for existing conveyor belt at this client’s facility to carry hot met coke, is Nylon. Life of this prevailing Nylon reinforced belt ranges between 6 – 9 months since rubber wear is very high due to extremely challenging thermal conditions. The belt shows up blisters on the surface, which leads to significant loss of rubber mass from the top cover and requires immediate maintenance. Further investigation showed that higher working temperature causes Nylon reinforcement to melt and the organic vapors from the already softened surface creates the blisters. The problem is critical not only from belt life’s perspective but also from load carrying capability perspective, since reinforcement degradation has already taken place at that temperature.
The reinforcement degradation could also be a potential safety issue in case the belt splits into two ends in running conditions, scattering the hot coke all over the place. It may be difficult even for steel reinforced belt to sustain in such conditions since the high working temperature can adversely affect the bonding of steel with rubber causing delamination, leading to damage or premature failure. Hence, the client was looking for more reliable conveyor belt solution, which has a life span of more than 12 months for high heat/temperature application and is safer than existing offerings.
DuPont partnered with Oriental Rubber, Pune (Belt Maker), Olbo Mehler Tex (Dipped Fabric maker) to understand the problem areas and application. Due consideration was given to thermal condition around the conveyor belt and the failure mechanism of the existing belt.
Based on the analysis of the existing problem Oriental, OMT & DuPont has agreed to provide more reliable and efficient belt solution for the customer. The team decided to change the incumbent reinforcement material (Nylon) by high strength, low creep, thermally and chemically stable Kevlar® as a carcass material and Kevlar® Engineered Elastomer as a part of rubber compound matrix in top and bottom cover to solve the issue faced by customer.
Based on current performance of the belt on the field it is expected to meet life expectancy of >12 month which is up to 50% better than the prevailing life. The belt is not stopped for any maintenance on account of belt reasons since it is put on work thus significantly reducing maintenance requirements in high heat applications compared to other heat resistant belt offerings in the market.
This belt solution is unique in terms of production continuity in high heat conditions coupled with lower maintenance costs, better belt life, efficient and safer operation and ease of installation due to lower belt weight. All this is a “Peace of Mind” in the journey of reaching Shunya loss in productivity and Shunya safety incidents in operations using Kevlar® reinforced conveyor belts.
Kevlar® reinforced conveyor belts enabled the customer to realize Shunya loss in productivity and Shunya safety incidents. According to best estimates, Kevlar® reinforced conveyor belts lasted six months more as compared to life of nylon reinforced belts, which was usually eight months. The customer also made effective use of Kevlar® reinforced conveyor belt after its productive lifespan.