Recycling of Waste Cooking Oils ( WCO ) to Biodiesel Production

Four different continuous process flowsheets for biodiesel production from virgin vegetable oil or waste cooking oil under alkaline or acidic conditions on a commercial scale were developed. Detailed operating conditions and equipment designs for each process were obtained. A technological assessment of these four processes was carried out to evaluate their technical benefits and limitations. Analysis showed that the alkali-catalyzed process using virgin vegetable oil as the raw material required the fewest and smallest process equipment units but at a higher raw material cost than the other processes. The use of waste cooking oil to produce biodiesel reduced the raw material cost. The acid-catalyzed process using waste cooking oil proved to be technically feasible with less complexity than the alkali-catalyzed process using waste cooking oil, thereby making it a competitive alternative to commercial biodiesel production by the alkali-catalyzed process.

Journal of Energy, 2013

Cost of biodiesel produced from virgin vegetable oil through transesterification is higher than that of fossil fuel, because of high raw material cost. To minimize the biofuel cost, in recent days waste cooking oil was used as feedstock. Catalysts used in this process are usually acids, base, and lipase. Since lipase catalysts are much expensive, the usage of lipase in biodiesel production is limited. In most cases, NaOH is used as alkaline catalyst, because of its low cost and higher reaction rate. In the case of waste cooking oil containing high percentage of free fatty acid, alkaline catalyst reacts with free fatty acid and forms soap by saponification reaction. Also, it reduces the biodiesel conversions. In order to reduce the level of fatty acid content, waste cooking oil is pretreated with acid catalyst to undergo esterification reaction, which also requires high operating conditions. In this review paper, various parameters influencing the process of biofuel production such a...

Biodiesel production from waste cooking oil (WCO) is an alternative source of biofuels. WCO is a cheaper raw material compared to other sources since it's a waste product. Visits to food outlets in Harare indicated an average 28.9% disposal of the total oils and fats consumed. Alkaline trans-esterification process was used for the conversion of WCO to biodiesel. Optimum operating conditions were employed and an average yield of 91.75% was obtained. An economic feasibility indicated a payback period of 4.43 years with the biodiesel selling at 0.95c/liter. The recovery of process water, alcohol and glycerin is recommended to improve the economic viability.

National conference at Bharathiar university

Abstract—In recent years, used vegetable oil from restaurant is utilized as fuel for on-road vehicles in the form of biodiesel. Used vegetable oil contains solid and free fatty acids and it must be determined experimentally using chemicals. Biodiesel, a methyl ester, from a trigyceride (vegetable oil) and either ethanol or methanol. The catalyst such as potassium hydroxide or sodium hydroxide is added within the process to increase the yield of biodiesel and to speed up the process, glycerol as a byproduct in this process. Waste cooking oil (WCO) was used as a potential feedstock for biodiesel production. High level of free fatty acids (9.85% w/w) in WCO makes it an undesirable substrate for direct transesterification reaction. To obtain a high quality biodiesel fuel, some important variables such as volumetric ratio, types of reactants and catalytic activities were selected. The highest approximately 99.5% biodiesel yield acquired under optimum conditions of 1:6 volumetric oil-to-methanol ratio, 1% KOH catalyst and 320 rpm stirring speed. In most cases, NaOH is used as alkaline catalyst, because of its low cost and higher reaction rate. The biodiesel synthesis condition was defined as the reaction temperature (338 K), methanol/ WCO molar ratio (6:1), KOH concentration (1% w/w) and reaction time (90 min). Under the above conditions, maximum TG conversion of 96.66 wt% was obtained.

With the increase in crude oil prices the need for development of economically attractive alternate fuels has increased. Biodiesel from waste cooking oil is one such alternative. The project involves setting up of a laboratory scale production unit for biodiesel conversion from waste cooking oil, collected from different sources. Methanol, with sodium hydroxide as a catalyst, reacts with the waste oil in the transesterification process producing Fatty Acid Methyl Esters (FAME) with glycerine as a by-product. Properties of the FAME sample including density, viscosity, flash point, pour point, sulphur content, cetane index and calorific value are tested according to ASTM standards and compared with those of standard diesel, establishing the FAME sample as biodiesel. The project also included blending of biodiesel with standard diesel and their properties were tested and compared. The production of biodiesel from waste cooking oil offers economic and environmental solutions along with waste management. The project, thus, aims at utilizing leftover cooking oil, for a possible conversion of biodiesel.

 Abstract: The present study proposed a rigorous model using detailed kinetics reaction for the alkali transesterification of waste cooking oil with methanol and Alkali Catalyst (NaOH). Aspen Plus software is used. The results showed that the rigorousness of the model helps in predicting more realism and accurate result. The effect of different parameters on the process like temperature, pressure, residence time, methanol to oil ratio, and catalyst (NaOH) weight percentage were studied. All the studied parameters have significant effect on the process performance except pressure. Optimization of the process also carried out to find the best conditions for maximum profit and maximum production. The optimization results showed that the reaction temperature decreased from 60 to 45 ° C, the reaction time decreased from 60 to 49 minutes, the molar ratio of methanol/oil increased from 6:1 to 7.2:1 mole ratio and the catalytic concentration decreased from 1 to 0.25 wt%.

International Journal of Sustainable and Green Energy, 2014

Growing concern regarding energy resources and the environment has increased interest in the study of alternative sources of energy. To meet increasing energy requirements, there has been growing interest in alternative fuels like biodiesel to provide a suitable diesel oil substitute for internal combustion engines. Biodiesels offer a very promising alternative to diesel oil since they are renewable and have similar properties. It is a promising substitute as an alternative fuel and has gained significant attention due to the predicted shortness of conventional fuels and environmental concern. The utilization of liquid fuels such as biodiesel produced from waste cooking oil by transesterification process represents one of the most promising options for the use of conventional fossil fuels. However, as the biodiesel is produced from vegetable oils and animal fats, there are concerns that biodiesel feedstock may compete with food supply in the long-term. Hence, the recent focus rely on using waste cooking oil as the substantial feed stocks for biodiesel production.

Due to the awareness of adverse effects of conventional fuels to environment and the frequent rise in crude oil's price , the need for sustainable and environment friendly alternate source of energy has gained importance in recent years. Biodiesel is proved to be the best replacement for diesel because of its unique properties like significant reduction in green house gas emissions, non-sulfur emissions, non-particulate matter pollutants, low toxicity and biodegradability. This paper reviews the pretreatment step, the physical and chemical properties of waste cooking oil, Esterification, Transesterification and production of Biodiesel from waste cooking oil by various methods and catalysts reported so far. The factors affecting the process parameters reported are studied and the point of interest focuses on their Alcohol to oil ratio, Reaction temperature, Catalyst both qualitative and quantitative scope. The optimum condition is investigated and the exhaust emissions of Biodiesel and Petroleum diesel are compared.

2010

In this work the conventional alkali-catalyzed transesterification process for biodiesel production from waste vegetable oils is studied considering the two process alternatives normally used industrially: with and without free fatty acids (FFA) pre-treatment. Simulation models of these process alternatives are developed using the chemical process simulator ASPEN Plus® and their potential environmental impacts (PEIs) and economic potentials are determined and compared. Results show that the contribution to total PEIs of the process alternative with the FFA pre-treatment is 25% higher than the alternative without pre-treatment. Concerning the economic potential the process alternative with the FFA pre-treatment is greater showing a net present value of about 1.8 times higher than the alternative without the FFA pre-treatment. The comparison using plant data will be performed as future work.

Renewable and Sustainable Energy Reviews, 2013

This paper aims at the assessment of the methods of production of biodiesel from different types of used cooking oil. Researches into the productive chain of this type of biofuel were performed in Brazil while several scientific studies approaching processes of pretreatment and transesterification of waste cooking oil were analyzed with their possible variations: alkaline catalysis, acid catalysis, enzymatic catalysis and non-catalytic conversion techniques, highlighting the main advantages and disadvantages of each analyzed route. The use of alkaline catalysts in transesterification is the most common technique employed by the industry, being the KOH the most recommended catalyst for the reaction with waste cooking oil. When water and acidity contents are high, pretreatment techniques and other types of catalysts such as solid acids are recommended. Moreover, the economic benefits provided by used cooking oil were analyzed, indicating reductions of up to 45% of direct production costs compared to virgin oils, even with the additional costs of the pretreatment. Finally, the availability of raw materials was estimated, indicating that the used cooking oil would have potential to supply up to 13% of the demand for biodiesel in Brazil.