(Nomination for 2011 AUREA Award): Faculty of Technology in Leskovac - Continuous biodiesel reactor

A team of experts from the Faculty of Technology in Leskovac have invented a plant for the continuous synthesis of biodiesel by methanolysis reaction at atmospheric pressure and low temperature. This innovative technological procedure enables smaller consumption of energy and reactants, which is why this type of biodiesel production is much cheaper than the existing one. The plant contains a new type of reactor where the reaction of triglyceride conversion takes place and it provides different reaction conditions. The value of the investment, exclusive of the time spent on development, is about €10,000.

The plant consists of two serially connected flow reactors with vibrating mixers (RVM) and two gravitational separators for separating non-mixable phases. The structure of the mixer (a series of perforated round panels on a common shaft) favors breaking of the drops of alcohol phase, increases the speed of the transfer of mass to interphase surface and creates a high speed of the process, even at room temperature. The reaction of alcoholysis of triglycerides is run with a very short time of stay of the reaction mixture in the reactor and at low temperature, achieving 98-100% yield of methyl ester.

By its concept and the capacity of 5 l/h, it is primarily oriented towards consumers needing about 1,000 liters of diesel fuel a year. Through application of well-known chemical-engineering principles for increasing the reactor’s proportions, the capacity of the plant can be significantly increased when needed. For now, the plant with such specific type of mixer, built-in technology and capacity is unique in the world.

INNOVATION

Existing biodiesel production technologies

The share of biofuels in overall fuel consumption in the world is constantly growing, while one of most popular biofuels is biodiesel. Biodiesel, which is a fuel comprised of mono-alkyl esters of long chain fatty acids, is made by the reaction of transesterification in the presence of a base serving as a catalyst. In countries all around the world, including Serbia, biodiesel is produced at numerous plants with various capacities. The technology used at plants for biodiesel production is based on the homogenously catalyzed reaction of the methanolysis of vegetable oils at temperatures close to the boiling point of methanol. In addition to the high temperature at which the reaction takes place, another important characteristic of the existing technological procedures is large amount of excessive methanol in regard to the required amount defined by the chemical reaction.

The innovative solution of the Faculty of Technology in Leskovac is the plant for continuous synthesis of biodiesel by the reaction of methanolysis at low temperature. The plant consists of two serially connected flow reactors with vibrating mixers (RVM) and two gravitational separators for separating non-mixable phases. In the continuous flow RVM, thanks to the periodic motion of the mixer, intensive mixing of non-mixable liquids takes place in each segment between perforated panels. Vibrational mixing, as well as the flow of phases through holes on the panels of the mixer, favors breaking of the drops of alcohol phase and reduces resistance to mass transfer in the border layer around the drops. As a result of the breaking of drops, the transfer of mass to the boundary of two non-mixable phases is accelerated, thus increasing the speed of the reaction of the conversion of triglycerides into fatty acid esters at low temperature. The use of RVM enables conducting of the process at atmospheric pressure and low temperature. The structure of the mixer (a series of perforated round panels on a common shaft) favors breaking of the drops of alcohol phase, increases the speed of the transfer of mass to interphase surface and creates a high speed of the process, even at room temperature. The reaction of alcoholysis of triglycerides is run with a very short time of stay of the reaction mixture in the reactor and at low temperature, achieving 98-100% yield of methyl ester.

Depending on the supplier, it takes between one and three months to build the plant. Production components are supplied by domestic suppliers, raw materials come from local plants (methanol, MSK, Kikinda), while oil (sunflower, oilseed rape) are supplied from cultivated fields of agricultural farms.

The plant comprises two elements that make its comparison with industrial plants possible. The first is the new type of reactor where the reaction of the conversion of triglycerides into methyl esters takes place, while the other concerns the conditions under which the reaction of methanolysis takes place.

By its concept and the capacity of 5 l/h, it is primarily oriented towards consumers needing about 1,000 liters of diesel fuel a year. Through application of well-known chemical-engineering principles for increasing the reactor’s proportions, the capacity of the plant can be significantly increased when needed. Depending on the quality of components and the possibility of servicing, the life of the plant ranges between 5 and 10 years if normally exploited (8 hours a day).

The plant developed at the Faculty of Technology in Leskovac is a result of many years of work on the studying of the kinetics of methanolysis reaction. Researches aimed at increasing the capacity of the plant and the transfer to the heterogenous system of running the reaction are underway. Many researchers from different fields are engaged in these researches.

SOCIAL UTILITY

What can be used in the production of biodiesel are renewable raw materials such as sunflower, soybean, oilseed rape, oil plants, and Serbia has a great potential for growing such cultures. In that way, in addition to the use of agricultural land, manpower is employed as well.

Farms with this plant on their grounds would be encouraged to produce oil plants because the price of fuel obtained from raw materials produced in that way is twice as low as the price of fuel in the oil derivatives market. A by-product of the squeezing process is also oilseed that can be used as fodder.

One of raw materials in the production of biodiesel can be thermally processed edible oil from restaurants. Each restaurant that prepares over 20 meals a day must separate waste edible oil and hand it over to operators. Although this is stipulated by a legal regulation, many catering facilities do not obey the adopted rules so that oil often ends in rivers. According to some estimates, Serbs consume 16 liters of edible oil per capita, which is about 10,000 tons of waste edible oil per year. Unfortunately, these quantities are still left unused.

An overall effect of exploitation of the plant lies in its contribution to: energy independence through the production of diesel fuel, social utility through the employment of manpower, and ecology through the use of a renewable energy source.

Biodiesel is an ecological fuel that does not cause the greenhouse effect, it is CO2 neutral and less inflammable then other types of fuel, it has better characteristics for lubricating the engine, and it is also an excellent solvent because, when used for the first time, it eliminates all the corrosion in fuel feed pumps. It can be mixed with diesel fuel in all proportions without any modifications of the engine. The life of biodiesel without additional additives is about six months, and what may be a problem is the fact that this fuel becomes thicker at low temperatures. That is why additives are necessary. A by-product of the biodiesel production is glycerin.

FINANCIAL POTENTIAL

The project is competitive when compared to existing technologies because it uses less energy and reactants, making the production cheaper. The users of the plant also benefit from the fact that the price of produced fuel is not affected by changes in the fuel prices in the global market. The plant is commercially oriented, the proof of which is the investment return time.

According to the projected price, the plant costs about €6,000. Since the users can use three types of raw materials in the production of biodiesel, the investment in the plant can be returned in 12 months if oil is purchased, 9 months if oil plants grown on a farm are used, or 6 months if waste edible oil from restaurants is used.

If the Continuous biodiesel reactor is your favorite for the innovative investment of the year, you can vote for this nominee on the official website of the 2011 Aurea Award.

Tehnološki fakultet Leskovac

eKapija.com Beograd

Aurea

2011

Continuous biodiesel reactor

biodiesel

methane

conversion

diesel

vegetable oil

canola

carbon dioxide

CO2

reaction

sunflower