435285 Utilization of Alkaline Wastes from Petrochemical Industry for CO2 Fixation and Supplementary Cementitious Material Production

Thursday, November 12, 2015: 9:12 AM
255E (Salt Palace Convention Center)
Shu-Yuan Pan1, Silu Pei1, Chen-Hsiang Hung1, Yin-Wen Chan2 and Pen-Chi Chiang1,3, (1)Graduate Institute of Environmental Engineering, National Taiwan University, Taipei, Taiwan, (2)Department of Civil Engineering, National Taiwan University, Taipei, Taiwan, (3)Carbon Cycle Research Center, National Taiwan University, Taipei, Taiwan

In this study, an integrated approach to establishing a waste-to-resource supply chain in the petrochemical industry was developed for CO2 fixation, wastewater neutralization and product utilization using a high-gravity carbonation (HiGCarb) process, i.e., rotating packed bed (RPB).  According to our previous experience, a high CO2 capture efficiency (i.e., >98%) can be achieved by utilizing basic oxygen furnace slag and cold-rolling wastewater via the HiGCarb process with a relatively short reaction time at ambient temperature and pressure.  Therefore, several alkaline wastes, such as byproduct lime, were gathered for performance evaluation operated under various levels of reaction temperature, rotation speed, and liquid-to-solid (L/S) ratio.  The alkaline wastes were found to be successfully carbonated with CO2 in the high-gravity carbonation process, where calcite (CaCO3) was identified as the main product.  In addition, the results indicated that the rates of metal ion leaching from the alkaline solid wastes can be prohibited by the high-gravity carbonation process.  Moreover, blended cements containing 5%, 10% and 20% replacements of ordinary Portland cement (OPC) with carbonated solid wastes were tested for compressive strength development and autoclave soundness.  The mortars were casted into 50 mm × 50 mm × 50 mm molds, and then tested at 3, 7, and 28 days according to ATSM C109.  Since the reacted product (e.g., carbonated solid wastes) can be used as supplementary cementitious materials, CO2 emissions from the cement industry can be avoided if a green waste-to-resource supply chain between the petrochemical and cement industries is established.  It was concluded that an integrated approach to the proper treatment of alkaline wastes that permanently fixes CO2 from the petrochemical industry while producing valuable supplementary cementitious materials for the cement industry can be achieved via the HiGCarb process.

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