Removal of chlorine, microparticles and water from high-viscosity liquids by a sand filter coupling hydrocyclone

Separation energy consumption in industrial production accounts for 10–15 % of global energy consumption. Nonthermal separation represented by sand filtration can open a new door to separation energy savings. Traditional sand filters cannot be regenerated completely, which limits their efficiency. A sand filter coupling hydrocyclone (SFCH) was proposed to enhance regeneration. The performance of SFCHs with different separation particle sizes was systematically analyzed, as indicated by turbidity, water, and chlorine in a pilot-scale experiment. The larger the sand particle size of the SFCH was, the longer it took to reach saturation. The efficiency and cycle were balanced by combining SFCHs with particle sizes of 1–2 mm and 0.5–1 mm. The average turbidity, water and chlorine decreased from 793 NTU, 1439 mg/L, and 126 mg/L to 155 NTU, 389 mg/L, and 88 mg/L, respectively, with a cycle of 88 h. Under the same conditions, the effluent turbidity of the SFCH was half of that of the original disc centrifuge, which indicates that the life of the downstream alumina bed was doubled. Almost 260 t/year alumina consumption can be reduced in a 200,000 tons/year-capacity petroleum resin plant, saving 600,000 USD/year, mainly due to the extension of the service life of the alumina bed.