Spent equilibrium catalyst for manufacturing fired bricks: A commercial production demonstration

Fluid catalytic cracking (FCC) is one of the most significant processes in refining crude oil into petroleum products, but the catalyst consumed in this process becomes waste. Current worldwide usage of zeolite-based FCC catalyst is about 500,000 metric tons per year, which results in producing about 360,000 metric tons of spent equilibrium catalyst (spent e-cat) each year. The majority of the spent e-cat materials is disposed of in landfills, but value-added applications could turn this waste into usable products that will also reduce the environmental risk and the economic burden of this landfill disposal. This zeolite-based spent e-cat from oil refinery operations, like coal fly ash and the conventional raw materials for fired bricks, consists primarily of silica and alumina. Our bench scale study (in a separate publication), using a mold-pressed method to form bricks, showed that fired bricks containing up to 30% by weight of spent e-cat could be successfully produced. This paper documents findings from a production demonstration where extrusion and firing facilities at a commercial brick plant were used to produce batches of 2000 bricks containing spent e-cat at two different levels, 14.3% by volume (13.5% by weight) and 28.6% by volume (27.2% by weight). The engineering properties of these bricks all met ASTM building brick specifications for the top level, severe weathering grade. In addition, acidic water extraction tests indicated that the final fired brick products, like conventional clay bricks, were environmentally safe construction materials. Thus, this waste material could be successfully incorporated into an environmentally sustainable product.