Byron Allen, Martin Engineering, details the upgrade of a hot clinker transfer point for a cement plant in Texas.
For thousands of years, cement production has heated the constituents used in the mix to the highest temperatures possible to remove impurities. Today, meal or raw material for Portland cement is calcined in a ~2000°F (~1000°C) kiln, akin to dropping it into the centre of an active volcano. Although the material is run through a cooling process afterwards, the light friable aggregate is still hot enough to burn through regular conveyor belting, high heat personal protective equipment (PPE), or pretty much anything else it encounters.
The presence of hot material has long made safety a priority for cement plant operators. However, regardless of the safety measures protecting individual workers, mitigating buildup and spillage in the hottest parts of the production process to avoid clogging and downtime is largely considered the least desirable job in the entire plant. Safety personnel at a cement plant in Texas raised attention to a transfer point leading from the cooling process to the tripper conveyor in the clinker barn. The transfer point struggled with excessive spillage of hot material and posed a potential risk to workers. This was an issue that the plant had been trying to address for some time, with the goal of reducing the amount of maintenance needed for repairs and cleanup in the area. Unscheduled downtime, increased labour and product loss were raising the cost of operation. By making the system more efficient, the plant also hoped to improve safety around the transfer point.
From kiln to storage
In the processing of approximately 200 tph (181.4 tph) of raw meal, molten clinker rolls out of the kiln, and is loaded onto a pan conveyor consisting of several high heat metal pans pulled by a chain. Cold air cools the cargo quickly, reducing it from nearly 1400°F (760°C) to a temperature range of between 350 – 800°F (176 – 426°C). Once the clinker is cooled, it is dropped through a 5 ft (1.5 m) long sloped chute onto a high-heat belt attached to a tripper conveyor that is suspended 80 ft above the massive piles along the length of the airplane hangar-sized clinker barn. With a length of 1100 ft (335 m) and a width of 24 in. (610 mm), the belt conveys material at 260 ft/m (1.32 m/s) toward the tripper discharge chute.
Moving slowly back and forth along the entire length of the barn, the tracked tripper system discharges chalky clinker through a chute onto tall piles for storage. The stored material is quickly moved by front loaders to different sections of the plant as needed.
Problems with the clinker tripper conveyor need to be addressed right away, otherwise these issues could hamper production and the plant’s ability to meet customer demand.
Found this article interesting? You can read the full version in the December issue of World Cement.
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Read the article online at: https://www.worldcement.com/special-reports/03122021/transfer-in-texas/
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