Subcritical ethylic biodiesel production from wet animal fat and vegetable oils: A net energy ratio analysis

Abstract

15Ethylic transesterification process for biodiesel production without any 16 chemical or biochemical catalysts at different subcritical thermodynamic con-17 ditions was performed using wet animal fat, soybean and palm oils as feed-18 stock. The results indicate that 2h of reaction at 240 o C with pressures vary-19ing from 20 to 45 bar was sufficient to transform almost all lipid fraction of 20 the samples to biodiesel, depending on the reactor dead volume and propor-21 tions between reactants. Conversions of 100%, 84% and 98.5% were obtained 22 for animal fat, soybean oil and palm oil, respectively, in the presence of wa-23 ter, with a net energy ration values of 2.6, 2.1 and 2.5 respectively. These 24 results indicate that the process is energetically favorable, and thus repre-25 sents a cleaner technology with environmental advantages when compared to 26 traditional esterification or transesterification processes. 27 2 28 Nomenclature. 29 AF: animal fat; FFA: free fatty acids; FAEEs: fatty acid ethyl esters; 30FAMEs: fatty acid methyl esters; GC: gas chromatography; IS: internal 31 standard; NER: Net Energy Ratio; TG: triglycerides; TGpcar: TG peak 32 corrected after reaction; TGpar: TG peak area after reaction; TGpbr: TG 33 peak area before reaction; ISpbr: IS peak area before reaction; ISpar: IS 34 peak area after reaction; TGtc: TG total conversion; TGpcar: TG peak 35 corrected area after reaction; FAEEsmax: Maximum possible formation of 36 FAEEs peak area; FFApbr: FFA peak area before reaction; E FAEEs : Energy 37 obtained from FAEEs; E cpm : Energy consumption from the power meter; 38 E rfr : Energy requirements for the reaction. 39 1. Introduction 40 The transesterification reaction of vegetable oils to produce fatty acid 41 methyl or ethyl esters (FAMEs or FAEEs) can be catalyzed by acids, bases 42 or enzymes, among other processes [1]. The predominant FAMEs employed 43 in the biodiesel industry in the world are derived from soybean, rapeseed, 44 and palm oils [2]. Currently, most commercial processes employ methanol 45 to perform the transesterification of triglycerides, catalyzed by a strong base 46 (KOH) in a homogeneous process to produce FAMEs. This is due to the 47 fast transesterification reaction in the presence of alcohol soluble bases and 48 to the low cost of alkaline material, but this process involves many treat-49 ment steps previous to and post-reaction, with generation of large amounts 50 of effluents and waste. Besides, the use of a soluble base as a catalyst is 51 not suitable for processing low quality raw materials, such as animal fat and 52 palm oil that usually contain traces of water and high amounts of free fatty 53 acids which readily react via the saponification reaction, generating soaps 54 and hindering the separation of the products, consumes the catalyst and re-55 duces its efficiency[3]. Likozar and Levec [4] performed a very detailed kinetic 56 study of the transesterification reaction of various vegetable oils, using vari-57 ous alcohols, via homogeneous catalysis with K...

Environmental and Economic Prioritization of Building Energy Refurbishment Strategies with Life-Cycle Approach

“…The second environmental indicator selected by this study is the net energy ratio (NER). This indicator has been mainly used to evaluate technologies or processes related to the energy sector [54][55][56][57][58]. However, despite its potential, its use in the evaluation of refurbishment projects is very limited.…”

Valorization of Wastes for Biodiesel Production: The Brazilian Case

“…Another comparative study was performed by Sales et al [45], in which ethylic transesterification without any chemical or biochemical catalysts at different subcritical thermodynamic conditions using wet animal fat, soybean oil, and palm oil as feedstocks was realized. Conversions of 100, 84, and 98.5% were obtained for animal fat, soybean oil, and palm oil, respectively.…”

Life Cycle Analysis of Rapeseed Oil Butyl Esters Produced from Waste and Pure Rapeseed Oil

“…Pleanjai and Gheewala [5] calculated the net energy ratios for palm oil methyl esters with and without by-products as 3.58 and 2.42, respectively. U.S. researchers established that the value of NER for canola oil methyl esters is 1.78 and that of soybean oil methyl esters is 2.05 [6]. The value of NER for fossil diesel fuel is 0.885, while the average corresponding net energy ratio for rapeseed oil methyl esters (RMEs) is 1.9.…”

“…As mentioned above, the net energy ratios of the following esters were determined: palm oil methyl esters at 2.42 [5] and canola and soybean oil methyl esters at 1.78 and 2.05, respectively [6]. Mohammadshirazi and colleagues performed an energy analysis of biodiesel production from waste cooking oil and determined that the energy ratio was 1.49 [15].…”

“…Sales et al [6] carried out net energy ratio analysis of subcritical ethylic biodiesel production from wet animal fat and vegetable oils. They determined that NER of their produced biodiesel is more than 2 [7].…”