Cogeneration Scenario in Cement Industry: A case study

1. COGENERATION OF POWER A Case Study of Cement Industry

2. Cement Industry: An Introduction An energy intensive industry consuming about 4GJ per tonne of cement produced. In dry process cement plants, nearly 40 percent of the total heat input is rejected as waste heat from exist gases of pre-heater and grate cooler. In India, the industry accounts for 10.3% of total fuel consumption in the manufacturing sector.

3. Process Description Procurement of Raw Materials Raw Milling – Preparation of raw materials for the pyro-processing system Pyroprocessing – pyroprocessing raw materials to form portland cement clinker Cooling of portland cement clinker Storage of portland cement clinker Finish milling Packing and Loading

4. Wet Process Raw Material Grinding Limestone Water Kiln Crusher Raw Mill Slurry Basin Storage Yard Slurry Tank Additives Clay basin Water Clay Wash Mill

5. Dry Process Raw Material Grinding EP Dryer Preheater and Kiln BT ST Storage Raw Mill Dryer Heat generated BT – Blending Tank ST – Storage Tank EP – Electrostatic Precipitator

6. Average Energy Consumption in a 1 MTPA Cement Plant Thermal Energy: 0.80 Million Kcal/Tonne Clinker Electrical Energy: 100 KWH/Tonne cement Coal Requirement: 2,00,000 Tonnes/Year Power Requirement: 20 MW (At 70% Load Factor)

7. Total Power & Captive Power Requirement for Various Plant Capacities * Taking Captive Power Requirement @ 30% of Total Power for Maintaining Continuous Production from Kiln

8. PREHEATER EXIT GAS, 300 – 400OC, 180-250 KCAL/KG COOLER EXIT GAS, 200 – 300OC, 80-130 KCAL/KG SOURCES OF WASTE HEAT

9. COGENERATION POTENTIAL IN INDIA Plants that are amenable for Cogeneration : 40 Total Cogeneration Capacity, MW : 160 Expected Power Savings : Upto 25 – 30% of Total Power Requirement can be achieved in a cement plant

10. CO2 Reduction Possibilities CO2 Reduction Potential : 1.50 (Million Tonnes per Year) Percentage Reduction as compared to emissions due to electricity consumption : 18

11. Power Generation through Waste Heat Recovery Utilization of waste heat from the Pre-Heater gases for power generation. Utilization of waste heat from AQC. Utilizing 40% Thermal Energy discharging into the atmosphere. Producing about 30% of Total Power Requirement for the Plant itself. Reducing CO2 amount in the atmosphere.

12. Technical Consideration For Cogeneration Schemes Availability of waste heat for cogeneration Location of Waste Heat Boiler Suitability of Waste Heat Recovery Boiler Maximum Flue Gas Temperature Quantity of Heat Recovery Type of Boilers, Turbines and Condensers De-dusting Arrangement Availability of Water

13. Recent Developments Improved Waste Heat Recovery Boiler (THERMOWIR) Removing 60% (48-60 gm/Nm3) dust from the gases reducing load on existing ESP Higher efficiency compared to conventional Heat Exchangers

14. Recent Developments Modified Rankine Cycle System “KALINA Cycle” Uses Binary fluid of Ammonia and Water Efficiency gains of upto 50% for low temperature (200-280oC) and upto 20% for higher temperature heat sources compared to rankine cycle

15. Recent Developments Organic Rankine Cycle (ORMAT Energy Convertor (OEC)) Uses organic fluid as working medium instead of steam Suitable for much lower temperature heat sources as organic fluid has a much lower boiling point as compared to water.

17. Case Study: 1.2MTPA, 4-Stage Preheater Cement Plant

18. Estimated Cogeneration Potential

19. Barriers in Adoption of Cogeneration Technology Technical Barriers Financial Barriers Institutional Barriers

20. Technical/Technological Barriers Non Availability of Proven technology indigenously. Design of waste heat recovery boiler suitable to withstand high dust load in the waste gases. High performance risk due to demonstration.

21. Financial Barriers Large Capital Requirement and financial constraints. Viability remains to be established. High cost of technology and access to funds. Depressed cement marketing scenario.

22. Institutional Barriers Lack of incentives for adoption of technology. Lack of capacity building efforts resulting in lack of operating experience and confidence level.

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