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Energy consumption of a rotary kiln in cement industry

The cement industry is one of the most energy-intensive industries in the world, which is why it is essential to research the feasibility and alternatives to reduce coal consumption and greenhouse gas emissions from rotary kilns in the industry. If we compare the cement industry with the other industrial sectors, the cement industry has consumed the largest proportion of energy and a typical well-equipped plant consumes around 4 GJ of energy to produce one ton of cement.

At the same time, the industry emits an increasing amount of greenhouse gases such as carbon dioxide, nitrogen oxide, chlorofluorocarbons, and methane. For every ton of clinker produced, an equivalent amount of greenhouse gases is emitted. Cement production in the world is approximately 3.6 billion tons per year.

Around 2% of the electricity produced worldwide is used during the grinding process of raw materials. The total electrical energy consumption for cement production is about 110 kWh/t cement, about two-thirds of this energy is used for particle size reduction. Due to the high energy consumption rates and the high environmental impact of the process, researchers have considered the manufacturing process for many years. Schuer and other researchers have studied energy consumption data and focused on energy saving methods for the German cement industry by considering electrical and thermal energy saving methods. Worell and other researchers were responsible for energy analysis in the US cement industry during the 1970s and 1997. Engin together with others analyzed a dry-type rotary kiln system with a kiln capacity of 600 tons of clinker per day. They found that about 40% of the total input energy was lost through the hot flue gases, the cooler stack, and the kiln shell. The study indicates that for a dry-type cement production process, the carbon dioxide emission intensity for a kiln inlet is about 5.4 kg of CO2 per ton of cement produced.

Cement production is a long process that consumes large amounts of fossil fuels and electricity. The process includes five main stages: (a) extraction and grinding of raw materials into fine powder, (b) mixing of the flour in homogenization silos before preheating in four-stage cyclone preheaters, (c) raising the raw meal temperature (precalcination) in the preheating tower with flue gases from the kiln, (d) burning the prepared raw meal mixture in a rotary kiln (calcination) after the preheating tower, and (e) grinding of the clinker in a cement mill.

Reduction in fuel consumption in a rotary kiln operation can be achieved by minimizing various losses that occur in the unit. The increase in combustion efficiency will be the main parameter in the system efficiency. Minimizing heat losses through effective insulation, reducing the temperature of the gases at the outlet through more effective heat transfer in the unit, and minimizing air and steam leaks using effective sealing systems at the kiln inlet and outlet are all measures that can help reduce energy consumption.

The Seal Plus by Motofrenos external lamella seal is a solution that contributes to the reduction of energy consumption per kilogram of clinker and to the efficiency of the kiln operation in the calcination process.

Source: https://www.researchgate.net/