Synthesis, Performance and Emission Quality Assessment of Ecodiesel from Castor Oil in Diesel/Biofuel/Alcohol Triple Blends in a Diesel Engine

Abstract

This research aims to promote the use of second-generation biofuels based mainly on Castor oil, which is not adequate for food use, and Sunflower oil as a standard reference for recycled oils. They have been applied in the production of Ecodiesel, a biofuel that integrates glycerol as monoglyceride, employing sodium methoxide as homogeneous catalyst and ethanol as solvent, but operating in milder conditions than in the synthesis of conventional biodiesel in order to obtain a kinetic control of the selective transesterification. The behavior of biofuels has been evaluated in a conventional diesel engine, operating as an electricity generator. The contamination degree was also evaluated from the opacity values of the generated smokes. The different biofuels here studied have practically no differences in the behavior with respect to the power generated, although a small increase in the fuel consumption was obtained in some cases. However, with the biofuels employed, a significant reduction, up to 40%, in the emission of pollutants is obtained, mainly with the blend diesel/castor oil/alcohol. Besides, it is found that pure Castor oil can be employed directly as biofuel in triple blends diesel/biofuel/alcohol, exhibiting results that are very close to those obtained using biodiesel or Ecodiesel.

Performance and Emission Quality Assessment in a Diesel Engine of Straight Castor and Sunflower Vegetable Oils, in Diesel/Gasoline/Oil Triple Blends

“…The contamination degree is evaluated from the opacity of the smoke generated in the combustion process. This is obtained by using an opacimeter (TESTO 308, Arquitecsolar, Granada, Spain) under the operating conditions studied, Figure 1b [16]. The data here compiled are the media of three repeated measures, attaining an experimental error lower than 6%.…”

“…The Pour Point and Cloud Point are determined by introducing the different double or triple blends, of different composition, in a glass tube having a flat bottom [16]. The tube was tightly closed with the help of a cork carrying a thermometer with a temperature measuring range of −36 to 120 • C. The tube was introduced in a digitally controlled temperature refrigerator for twenty-four hours.…”

“…Following a previously described experimental methodology [16], the mechanical and environmental characterization of a compression ignition diesel engine has been carried out, working at a rate of 3000 rpm coupled to an AYERBE electric generator, 5KVA, 230v type AY4000MN, for the generation of electricity, operating at a crankshaft constant rotation rate and under different degrees of demand for electrical power. This is achieved by connecting heating plates of 1000 watts each one ( Figure 1a).…”

“…Nevertheless, there is a very interesting exception when castor oil is employed as an SVO due to the special structure of ricinoleic acid, which favors its solubility with alcohols, making possible a higher incorporation of them in triple blends. In fact, a diesel/castor oil/2-propanol triple blend in a proportion of 50/25/25 has been employed in conventional diesel engines, achieving very good results [16,17].…”

Biodiesel Production from Castor oil by Two-Step Catalytic Transesterification: Optimization of the Process and Economic Assessment

“…This compound is the main cause of the high viscosity and polarity of castor oil [4]. Such properties would limit its use as a biodiesel; nevertheless, as is usually done for other biodiesel samples [5], mixtures with castor oil biodiesel show good properties when mixed with conventional diesel or other less viscous biodiesels [6], and can also be used in mixtures as oil [7]. In addition, castor oil shows high solubility in alcohols, which favors transesterification [8].…”