Use of lamella clarifiers for juice and syrup clarification at a direct-white cane-sugar plant

Abstract

The Andhra Sugars Ltd. has been working on improving the clarification process. A conventional Graver HRT (high retention time) clarifier with a retention time of 150 min at the Tanuku sugar plant was replaced by an SRI-NG (short retention time) SRT clarifier with a residence time of 45 min. A Louisiana Low Turbulence (LLT) SRT clarifier with a residence time of 37 min was then installed on a pilot scale at the Taduvai sugar plant and successfully ran parallel to an existing Graver clarifier. In the off crop, the Graver clarifier was modified to an LLT clarifier. Lamella plate clarifiers are successfully used for many applications, and The Andhra Sugars Ltd. tried lamella clarifiers for juice and syrup clarification during the 2019/20 season. A lamella clarifier with a juice retention time of 7 min was built and used at the Taduvai sugar plant. Based on the encouraging results of the lamella juice clarifier, a lamella syrup clarifier with a syrup retention time of 9 min was installed and operated. The performance of the lamella juice and syrup clarifiers over three consecutive seasons is described. Product quality from the lamella clarifiers was as good as or better than that obtained from conventional clarifiers. The clarifiers operated with significantly lower residence times, with beneficial implications for sugar losses and heat losses. The lamella clarifiers have considerably higher surface loadings than other clarifiers, and their compact size results in much reduced capital costs.