The fly ash, primarily dry fly ash (about 80%) collected from flue gases via electrostatic precipitators at Patratu Thermal Power Station (PVUNL), is stored in silos before pneumatic transport to UltraTech Cement's Patratu Works. It is pumped directly from closed bulkers into silos in a closed-loop system to prevent fugitive emissions, then integrated as a raw material substitute (up to 30% in PPC) alongside slag for blended cement production per Bureau of Indian Standards.
Fly ash is fed from silos into mills (e.g., ball mills or vertical roller mills) after metering, where coarse particles are pulverized to below 325 mesh, increasing surface area and breaking spherical microbeads for better cement integration. Open-circuit grinding directly produces fine Grade I/II ash without separation, while closed-circuit systems recirculate coarse material for regrinding until uniform fineness. Dust collectors capture fines during milling, minimizing emissions.
UltraTech incorporates the fly ash as a pozzolanic substitute in blended cements such as Portland Pozzolana Cement (PPC) and Portland Composite Cement (PCC), reducing clinker needs and carbon emissions. For instance, from December 2023 to June 2024, the plant used over 9,500 MT of fly ash for PPC and additional amounts for PCC production. This process leverages fly ash's properties to enhance concrete durability without extensive further processing beyond drying and transport.
🧑🏻🏫 Sudesh Kumar
