Environmentally benign biodiesel production by heterogeneous catalysis

Process options to minimise the environmental impact and improve the efficiency of biodiesel production have been investigated. The process options considered include the use of heterogeneous catalysts and used cooking oil (UCO). An esterification pre-treatment reaction was investigated using an ion-exchange resin (Purolite D5082) and an immobilised enzyme (Novozyme 435). Another immobilised enzyme (Amano Lipase PS-IM) was investigated for transesterification. The fresh and used catalysts have been characterised. The catalytic activity of Purolite D5082, Novozyme 435 and Amano Lipase PS-IM have been investigated using a jacketed batch reactor with a reflux condenser. Purolite D5082 has been developed for the esterification pre-treatment process and is not commercially available. Novozyme 435 has been shown to be an effective esterification catalyst for materials with high concentrations of free fatty acid but it has not been investigated for the esterification pre-treatment reaction. It was found that a high conversion was possible with both catalysts. The optimum reaction conditions identified for Purolite D5081 were a temperature of 60 C, a methanol to free fatty acid (FFA) mole ratio of 62:1, a catalyst loading of 5 wt% resulting in a FFAs conversion of 88% after 8 h of reaction time. The optimum conditions identified for Novozyme 435 were a temperature of 50 C, a methanol to FFA mole ratio of 6.2:1 and a catalyst loading of 1 wt% resulting in a conversion of 90% after 8 h of reaction time. These catalysts were compared to previously investigated Purolite D5081 and it was found that the highest conversion of 97% was achieved using Purolite D5081, however there were benefits to using Novozyme 435 because the reaction could be carried out using a much lower mole ratio, at a lower temperature and in much shorter reaction time. During the Novozyme 435 catalysed esterification pre-treatment reactions it was found that the amount of free fatty acid methyl esters (FAME) formed during the reaction was greater than the amount of FFAs consumed. In order to investigate further an ultra-performance liquid chromatography mass spectrometry (UPLC-MS) method was developed to monitor the monogclyeride (MG), diglyceride (DG) and triglyceride (TG) concentrations. This analytical method was used to show that Novozyme 435 would catalyse the esterification of FFAs as well as the transesterification of MGs and DGs typically found in UCO. With the UPLC-MS method it was possible to separate the 1, 2 and 1, 3 DG positional isomers and from this it could be seen that the 1, 3 isomer reacted more readily than the 1, 2 isomer. The results from the UPLC-MS method were combined with a kinetic model to investigate the reaction mechanism. The kinetic model indicated that the reaction progressed with the sequential hydrolysis esterification reactions in parallel with transesterification. Commercially available Amano Lipase PS-IM was investigated for the transesterification reaction. Enzymes are not affected by FFAs and as a result the optimisation was carried out with UCO as the raw material. An optimisation study for the transesterification of UCO with Amano Lipase PS-IM has not previously been reported. The conditions identified for the Amano Lipase PS-IM catalysed transesterification step are addition of 5 vol% water, a temperature of 30 C, a methanol to UCO mole ratio of 3:1 and a catalyst loading of 0.789 wt% resulting in a TG conversion of 43%. An overall enzyme catalysed process was proposed consisting of Amano Lipase PS-IM catalysed transesterification (stage 1) followed by Novozyme 435 catalysed esterification (stage 2). The previously identified optimum conditions identified for each catalyst were used for above stages. It was found that when the oil layer from stage 1 was dried the final TG conversion was 55%

Comparison of Novozyme 435 and Purolite D5081 as heterogeneous catalysts for the pretreatment of used cooking oil for biodiesel production

The catalytic performance of two types of catalysts, an ion-exchange resin, Purolite D5081 and an immobilised enzyme, Novozyme 435, was compared for the esterification pretreatment of used cooking oil (UCO) for the preparation of biodiesel. The reactions were carried out using a jacketed batch reactor with a reflux condenser. The effect of mass transfer limitations was investigated and it was shown that internal and external mass transfer limitations were negligible. An immobilised enzyme, Novozyme 435, was investigated because it has been shown to give high free fatty acids (FFAs) conversion. This catalyst has been compared to an ion-exchange resin, Purolite D5081, which was developed for the esterification of UCO for the production of biodiesel. It was found that a conversion of 94% was achieved using Purolite D5081 compared to 90% conversion with Novozyme 435. However, the optimum methanol to FFA ratio for Purolite D5081 was 98:1 compared to 6.2:1 for Novozyme 435. In addition, it has been found that with Novozyme 435 there are side reactions which result in the formation of additional fatty acid methyl esters (FAMEs) and FFAs at longer reaction times

Esterification of free fatty acids (FFAs) in used cooking oil (UCO) using ion-exchange resins as catalysts

Esterification of free fatty acids (FFAs) in used cooking oil (UCO) using ion-exchange resins as catalyst

Pre-treatment of used cooking oil for the manufacture of biodiesel using heterogeneous catalyst

Pre-treatment of used cooking oil for the manufacture of biodiesel using heterogeneous catalys

Comparison of catalytic performance of Novozyme 435 and Purolite D5081 for the esterification pre-treatment of used cooking oil for biodiesel production

Comparison of catalytic performance of Novozyme 435 and Purolite D5081 for the esterification pre-treatment of used cooking oil for biodiesel productio

Comprehensive Axillary Evaluation in Neoadjuvant Chemotherapy Patients With Ultrasonography and Sentinel Lymph Node Biopsy

There is ongoing debate regarding the optimal sequence of sentinel lymph node (SLN) biopsy and neoadjuvant chemotherapy (CTX) for breast cancer. We report the accuracy of comprehensive pre–neoadjuvant CTX and post–neoadjuvant CTX axillary staging via ultrasound imaging, fine-needle aspiration (FNA) biopsy, and SLN biopsy.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/41405/1/10434_2005_Article_6534.pd

Comparison Of Novozyme 435 And Purolite D5081 As Heterogeneous Catalysts For The Pretreatment Of Used Cooking Oil For Biodiesel Production

The catalytic performance of two types of catalysts, an ion-exchange resin, Purolite D5081 and an immobilised enzyme, Novozyme 435, was compared for the esterification pretreatment of used cooking oil (UCO) for the preparation of biodiesel. The reactions were carried out using a jacketed batch reactor with a reflux condenser. The effect of mass transfer limitations was investigated and it was shown that internal and external mass transfer limitations were negligible. An immobilised enzyme, Novozyme 435, was investigated because it has been shown to give high free fatty acids (FFAs) conversion. This catalyst has been compared to an ion-exchange resin, Purolite D5081, which was developed for the esterification of UCO for the production of biodiesel. It was found that a conversion of 94% was achieved using Purolite D5081 compared to 90% conversion with Novozyme 435. However, the optimum methanol to FFA ratio for Purolite D5081 was 98:1 compared to 6.2:1 for Novozyme 435. In addition, it has been found that with Novozyme 435 there are side reactions which result in the formation of additional fatty acid methyl esters (FAMEs) and FFAs at longer reaction times

Environmental impact assessment of lignocellulosic lactic acid production: Integrated with existing sugar mills

Lactic acid (LA) is considered for the diversification and value addition to sugar industry in South Africa, through a bioconversion of sugarcane bagasse and leaves. A bioconversion process was modeled in Aspen Plus (R) V8.6 and its environmental impacts were evaluated using the Life Cycle Assessment method using SimaPro (R) considering its integration into existing South African Sugar mills. The life cycle approach took into account the whole sugar production chain, including sugarcane cultivation stage, harvesting and transportation of sugarcane, sugar mill, and LA production. The life cycle inventories of the sugarcane cultivation and sugar mill were obtained from literature while Aspen Plus (R) simulation data were used for the LA production. The ecoinvent database of SimaPro (R) was used for all external inputs and fossil-based LA production. Environmental impacts of the biobased and fossil based LA productions were assessed and compared. The total environmental savings of the major impact categories obtained upon replacing a tonne of fossil-based LA with biobased LA are: 3925.65 kg CO2 eq. of global warming potential; 1742.05 kg fossil fuel eq. of abiotic depletion potential; 1296.16 kg 1,4-DB eq. of human toxicity potential; 397.79 kBq U-235 eq. of ionizing radiation potential; 253.97 kg Fe eq. of metal depletion potential; 43.48 kg 1,4-DB eq. of marine aquatic ecotoxicity potential; 42.97 kg 1,4-DB eq. of fresh water aquatic ecotoxicity potential and 18.23 kg SO2 eq. of acidification potential. Auxiliary chemicals used in the biobased LA production are most relevant to the total environmental impacts. Thus, biobased LA production has significantly reduced the impact on the environment, giving 80-99% environmental savings compared to fossil-derived LA. (C) 2016 Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved

Kinetics of the pre-treatment of used cooking oil using Novozyme 435 for biodiesel production [conference paper]

The pretreatment of used cooking oil (UCO) for the preparation of biodiesel has been investigated, using Novozyme 435, Candida antarctica Lipase B immobilized on acrylic resin, as the catalyst. The reactions in UCO were carried out using a jacketed batch reactor with a reflux condenser. The liquid chromatography mass spectrometry (LC-MS) method was developed to monitor the mono-, di and triglyceride concentrations for this work and it has been shown that it is possible to obtain linear calibration curves. This work showed that Novozyme 435 will catalyse the esterification of FFAs and the transesterification of mono- and diglycerides typically found in UCO when Novozyme 435 is used to catalyse the pretreatement of UCO for the formation of biodiesel