Additional Preheater Cyclone Stages

Energy savings can be achieved within certain limits to raw materials moisture by reducing the temperature of the hot gas through heat recovery with an additional cyclone stage. The higher the number of preheater cyclone stages is, the lower is the temperature reduction potential for the gas. A 6-stage preheater precalciner plant using fossil fuels shows raw gas temperatures of about 280 - 290 °C, a 5-stage preheater 310 - 320 °C, a 4-stage preheater 340 - 350 °C and a 3-stage preheater (which is not very common) more than 500 °C.  The addition of an extra pre-heater step may reduce the amount of heat available for material drying in the raw mills and will also increase the electricity consumption in the required fans.  The addition of a cyclone stage is only feasible, e.g. if the original design was very conservative, or high amounts of secondary fuels are used, especially in the calciner.

 

Development Status Products
Commercial

Additional Preheater Cyclone StagesCosts & Benefits

Parent Process: Clinker Making
Energy Savings Potential

Moving from 4 stage to 5 stage, or from 5 stage to 6 stage can reduce the specific heat energy consumption between 0.08 to 0.1 GJ/t clinker

Indian flag In India reductions between 0.06 to 0.1 GJ/t clinker are reported.  

CO2 Emission Reduction Potential

Chinese flag CO2 emissions can be reduced by 7.6 – 9.5 kg/t-clinker.

Indian flag  CO2 emissions can be reduced by 7.9 – 9.9 kg/t-clinker.

Costs

Additional Preheater Cyclone StagesSchematic

Additional Preheater Cyclone Stages Publications

Development of State of the Art Techniques in Cement Manufacturing: Trying to Look Ahead

The report represents the independent research efforts of the European Cement Research Academy (ECRA) to identify, describe and evaluate technologies which may contribute to increase energy efficiency and to reduce greenhouse gas emissions from global cement production today as well as in the medium and long-term future. 

Page Number: 

34-35