Feasibility Study on Membrane‐Aided Cleanup and Fractionation of Fatty Acid Esters Produced from Waste Fats

Abstract

Significant efforts are being made to replace mineral oil by renewable raw materials in technical products such as lubricating oils. Energy-and cost-effective production and refinement routes for such oils, e. g., fatty acid esters, are in progress. In this context, a feasibility study is performed into whether the application of membrane-aided separation procedures is suitable for the hydrophobic matrix of fatty acid methylesters (FAME). It is found that an enrichment of saturated acid esters from 28 to 51% is possible in just three steps for an unsaturated fatty acid ester matrix. The free fatty acids content can also be considerably reduced. This cleanup effect can be enhanced by the inclusion of a basic additive. Background and AimsOne example of today's attempts to substitute technical mineral oil fluids by those based on renewable raw products are cooling lubricants, which are applied for metal-working processes. These fluids are responsible for cooling and lubricating the contact area between the tool and the workpiece and also rinse the resulting chips away. About 1.2 million tons of lubricants are employed in Germany annually. However, these highly additive-amended fluids cause work related physiological and ecological problems during application and disposal.Fatty acid esters as base oils produced from plant oils are already being developed as alternative lubricants. Although offering remarkable advantages, they are rarely applied in practice, because of their comparably high price resulting from raw materials and production costs [1,2]. By considering the cost factor, the production of fatty acid esters was recently initiated from cheap waste edible and animal fats, which are substantially more economical raw materials [3,4]. In this respect, processes must be developed that yield high quality ester products from waste fats without losing the advantage of low-cost raw materials due to particularly high costs for production and refinement [5]. Today, the latter consists of cost and energy intensive production steps, e. g., distillation under reduced pressure, catalytic hydrogenation and fractional crystallization [6].In this context, the approach of producing the fatty acid esters by means of enzymatic alcoholysis is surely a valuable step [7,8]. Furthermore, the question has arisen as to whether the use of membranes for cleanup and separation processes could also contribute to a low-cost and energy saving modern production process for customized technical fatty acid ester oils. Only a few publications are cited in the literature for examining this focused direction and these are mostly applied for edible oil treatment [9 -15]. Therefore, the aim of this feasibility study was to examine the efficiency of membranes in the ester oil production process. Materials and Methods DialysisThe separation efficiencies of membranes were tested by dialysis under ambient pressure. The self-constructed dialysis device is depicted in Fig. 1. The fatty acid methyl esters (FAME) used for these experiments were all indus...

Esterification and Deacidification of a Waste Cooking Oil (TAN 68.81 mg KOH/g) for Biodiesel Production

“…To reduce the cost of biodiesel, in general, the selection of oil feed is very critical. The oil feeds containing high free fatty acids (FFA), such as waste fats or non-edible type oils, are much cheaper than vegetable oils, such as soybean or rapeseed oil [8][9][10]. In China, biodiesel is mainly produced from non-edible and waste oils and fats such as tung oil, Jatropha curcas L. oil, waste cooking oil (WCO), trapped grease, soapstock and acidified oil [11].…”

Chemical transformations of renewable lubricant feedstocks

“…Biodegradable lubricants were also obtained by reaction of various Indian vegetable oils (neem, rice bran, linseed, castor, pongamia and jatropha oils) and long-chain (C 5 -C 10 ) alcohols [99]. In the context of cost-effective production and refi nement routes of lubricating oils, membrane-added separation procedures of unsaturated FAMEs were reported, resulting in enrichment of saturated acid esters and reduction of free fatty acids (FFAs) [100]. Transesterifi cation of castor oil with C 1 -C 10 diols gives diol esters and reaction of these esters with NaOMe gives estolides [101].…”

Improving the Cold Flow Properties of Biodiesel by Fractionation

“…Results showed the rates of retention in descending order were triacylglycerol > diacylglycerol > monacylglycerol > fatty acids suggesting this technique may be useful in cleaning transesterification product streams or reducing effects of monoacylglycerol on cold weather storage stability of biodiesel. Low-pressure dialysis was applied in the partial separation of UCOME into saturated and unsaturated FAME-rich fractions (Wichmann et al, 2008). The experimental apparatus consisted of a pocket shaped from the dialysis membrane holding within it the UCOME and www.intechopen.com surrounded on the outside by n-hexane.…”