Economic and environmental analysis of spent bleaching earth reactivation

Abstract

One of the stages in edible oil refining is bleaching, which aims to reduce pigments, gums and metals. Bleaching produces large amounts of spent bleaching earth (SBE) solid waste. SBE is usually treated in traditional processing such as landfill, incineration, compost or using the services of third-party. This paper investigated the best scheme for reactivation of SBE based on economic and environmental aspects. The basis of economic and environmental analysis used reactivated SBE with the best treatment, i.e. extraction of residual oil using n-hexane, thermal activation at 600°C for 60 minutes, acid activation using HCl 10% with impregnation BaCl2 5% (RBE-Ba) and without impregnation (RBE). BET analysis results of RBE-Ba and RBE were obtained with a pore surface area of 160 and 150 m2/gr, a total pore of 0.209 and 0.11 cc/gr, and a total pore size of 2.62 and 6.14 nm. The reactivation schemes being compared were build a new plant (NP) in an existing factory and build a new factory (NF). The most profitable scheme is RBE NP, with ROI is 20.97 % and PBP is 3.23 years. RBE NP is more economical because there is no need to buy new land, buildings, transportation, and low cost for chemicals and labour. NPV of RBE NP is USD 446,633.71, IRR is 15%, and B/C ratio is 53.31%. Based on environmental aspect, it can reduces air pollution resulting from SBE transportation, the risk of water and air contamination, and RBE will reduce the mining of bentonites to prevent environmental damage.