Handheld near-infrared spectrometer for on-line monitoring of biodiesel production in a continuous process. (15th October 2019)

• Record Type: Journal Article
• Authors: Sales, Rafaella; da Silva, Neirivaldo C.; da Silva, Josivan P.; França, Higor H.; Pimentel, Maria Fernanda; Stragevitch, Luiz
• Is Part Of: Fuel. Volume 254(2019)
• Publication Date: 2019-10-15
• Subjects: Near infrared -- Handheld spectrometer -- Process monitoring -- Biodiesel production -- Reactive distillation; Fuel -- Periodicals; Coal -- Periodicals; Coal; Fuel; Periodicals; 662.6
• DOI: 10.1016/j.fuel.2019.115680
• Languages: English
• ISSNs: 0016-2361

Abstract

Graphical abstract: Highlights: Handheld near-infrared spectrometer to on-line monitor biodiesel production. Transesterification reactions conducted in continuous reactive distillation column. PLS regression models for monitoring ethanol, glycerol and alkyl ester contents. Calibration models used for estimation of alkyl ester yield. Abstract: In this work, the use of a handheld near-infrared spectrometer (MicroNIR) for on-line monitoring of biodiesel production in a continuous process is described. The process consists of a laboratory scale reactive distillation column where transesterification reactions between cottonseed oil and ethanol take place. This column can operate with different ethanol to oil molar ratios. In the present study, a severe condition using an excess of ethanol at the point monitored with NIRS was applied. This condition caused problems in modelling the content of the alkyl ester, particularly because of the broad and intense band related to the ethanol in the spectral region covered by MicroNIR. Therefore, for process monitoring and control, both an estimate of the alkyl ester as well as of ethanol contents were carried out. To deal with this, PLS calibration models were developed to estimate concentrations of ethanol and alkyl ester at the bottom of the column. In addition, in order to estimate the yield of the alkyl ester, a PLS model to assess glycerol content was also developed. In spite of the problematic conditions under which the column operated, mainly related to the excess of ethanol, the models presented satisfactory results for ethanol (RMSEP = 1.66 wt%), alkyl ester (RMSEP = 2.15 wt%) and glycerol (RMSEP = 1.08 wt%) quantifications and have demonstrated the feasibility of the handheld instrument to monitor biodiesel production in a continuous process.