Designing Green Cement Plants
Contents: 1. Green Cement. 2. Blended Cements. 3. Carbon Capture and Storage Systems. 4. Alternate Fuels and Raw Materials. 5. Waste Heat Recovery Systems. 6. Other Aspects of Green Cement Plants. 7. Features of Large Green Cement Plants. 8. Capital Costs and Costs of Production. 9. Cement Substitutes. 10. Conclusion. 11. Sources. Index.
This Book is about Designing new large cement plants that would promote Sustainable Growth, preserve natural resources to the maximum possible extent and make least possible additions to the Greenhouse Gases that cause global warming. These are the Green Cement Plants.
Process of making cement involves 'calcination' of limestone-that is release of Carbon Dioxide the principal greenhouse gas. In ordinary portland cement, OPC, ratio of cement to clinker is 1.05. Every ton of cement produced releases 0.8 ton of Co2. By increasing the cement/clinker ratio that is by making 'blended cements' this emission can be reduced to 0.53 to 0.30 tons per ton of cement depending on the type of blended cements viz. PPC, BFSC or composite cements made.
Combustion of fuel-needed to make clinker also releases CO2 (quantum included in values mentioned above) Reduced sp. fuel consumption thus reduces ghg emissions. Substitution of fossil fuels by waste-alternate fuels some of which are 'carbon neutral' thus saves exhaustible fossil fuels and also lowers ghg emissions.
Presently a lot of heat is wasted thru kiln and cooler exhaust gases even after they are used to dry raw materials and coal. If the heat therein is recovered to generate power, a dual advantage accrues in that fossil fuel is saved and ghg emissions are lowered.
World is paying urgent attention to harnessing inexhaustible and renewable sources of energy like wind and sun. Both Solar and wind power are renewable and ghg emissions are practically nil. New cement plants should therefore be designed to use renewable energy to the extent possible depending on the present day status of cost and production factors.
There are other ways of reducing CO2 emissions like capturing the emitted gas and either storing it for other uses or for making new cements like Calera. New green cement plants should also examine possibilities of developing cement substitutes like Calera, Caliix, Novacem, Aether and Geopolymer cements etc. that are 'green cements'.
The concept of saving energy and saving materials by recycling are also applied to construction of cement plants by constructing green buildings, to mining operations and so on.
All these aspects and activities add up to making 'Green Cement'. They have been dealt with in the book. Large new cement plants should be designed to incorporate all these aspects. Cement making machinery to be selected and cement plant layouts to be developed should also contribute to this concept of 'green cement'.
This book like its predecessor 'Handbook for Designing Cement Plants would be a useful tool in the hands of Cement Engineers, Cement Technologists and Cement Consultants to achieve the objective of the day viz sustainable growth thru Green Cement.
