Review on energy conservation and emission reduction approaches for cement industry

Cement production utilizes a considerable amount of energy which is also responsible for different greenhouse gas emissions. This review aims to help the cement industry to select the best method for improving energy efficiency and emission reduction. Various energy conservation and emission reduction approaches are considered for raw meal preparation, clinker manufacturing and cement grinding and include energy conservation approaches in support process of cement manufacturing. Raw meal preparation, clinker manufacturing, and cement grinding recorded the highest thermal energy savings of 4.30 GJ/t, 2.4 GJ/t, and 0.29 GJ/t, respectively. Gravity-type silos are the best blending system for the dry process, saving a maximum of 4.30 GJ/t of thermal energy. Furthermore, the use of advanced roller mills, Waste gas from rotary kiln and Up-gradation of mill for finish grinding can save a maximum of 11.9 kWh/t, 17.84 kWh/t, and 25.93 kWh/t electrical energy, respectively. Additionally, the highest recorded emission reduction value was 10.45 kgCO2/t, 112.61 kgCO2/t and 26.66 kgCO2/t which are possible through advanced roller mills, implementing preheater/precalciner kiln system and up-gradation of mill system, respectively. This work will facilitate the researchers in knowing the current status of energy-saving practices and will encourage them to further research in this field.