The manufacture of Biodiesel from used cooking oil

ABSTRACT 

 

                  The increasing awareness of the depletion of fossil fuel resources and the environmental benefits of biodiesel fuel has made it more attractive in recent times. Its primary advantages deal with it being one of the most renewable fuels currently available and it is also non-toxic and biodegradable. It can also be used directly in most diesel engines without requiring extensive engine modifications. However, the cost of biodiesel is the major hurdle to its commercialization in comparison to petroleum-based diesel fuel. The high cost is primarily due to the raw material, mostly neat cooking oil. Used cooking oil is one of the economical sources for biodiesel production. However, the products formed during frying, can affect the transesterification reaction and the biodiesel properties.  

 

The production of biodiesel from waste cooking oil offers a triple-facet solution: economic, environmental and waste management. The new process technologies developed during the last years made it possible to produce biodiesel from recycled frying oils comparable in quality to that of virgin cooking oil biodiesel with an added attractive advantage of being lower in price. Thus, biodiesel produced from recycled frying oils has the same possibilities to be utilized. From an economic point of view; the production of biodiesel is very feedstock sensitive. Many previous reports estimated the cost of biodiesel production based on assumptions, made by their authors, regarding production volume, feedstock and chemical technology. From a waste management standpoint, producing biodiesel from used frying oil is environmentally beneficial, since it provides a cleaner way for disposing these products; meanwhile, it can yield valuable cuts in CO2 as well as significant tail-pipe pollution gains.  

 

Any fatty acid source may be used to prepare biodiesel. Thus, any animal or plant lipid should be a ready substrate for the 

 

production of biodiesel. The use of edible cooking oils and animal fats for biodiesel production has recently been of great concern because they compete with food materials - the food versus fuel dispute (Pimentel et al., 2009; Srinivasan, 2009). There are concerns that biodiesel feedstock may compete with food supply in the long-term. Hence, the recent focus is the use of non-edible plant oil source and waste products of edible oil industry as the feedstock for biodiesel production meeting the international standards. Quality standards are prerequisites for the commercial use of any fuel product.  

 

This Master Thesis is about the manufacturing of biodiesel from the used cooking oil. This study aims to define the requirements for biodiesel production by the esterification process, testing its quality by determining some parameters such as density, kinematics viscosity, high heating value, cetane number, flash point, cloud pint and pour point and comparing it to Diesel fuel, testing the engine performance, testing the emissions of biodiesel and comparing it to diesel emission, and the strategic issues to be considered to assess its feasibility, or likelihood of succeeding. This analysis is useful either when starting a new business, or identifying new opportunities for an existing business. Therefore, it will be extremely helpful for taking rational decisions about the development of a biodiesel production plant. 

 

 

INTRODUCTION 

 

During the last century, the consumption of energy has increased a lot due to the change in the life style and the significant growth of population. This increase of energy demand has been supplied by the use of fossil resources, which caused the crises of the fossil fuel depletion, the increase in its price and the serious environmental impacts as global warming, acidification, deforestation, ozone depletion, Eutrophication and photochemical smog. As fossil fuels are limited sources of energy, this increasing demand for energy has led to a search for alternative sources of energy that would be economically efficient, socially equitable, and environmentally sound. Two of the main contributors of this increase of energy demand have been the transportation and the basic industry sectors, being the largest energy consumers. The transport sector is a major consumer of petroleum fuels such as diesel, gasoline, liquefied petroleum gas (LPG) and compressed natural gas (CNG)’ (Demirbas, 2006). Demand for transport fuels has risen significantly during the past few decades. (IEA, 2008). The demand for transport fuel has been increasing and expectations are that this trend will stay unchanged for the coming decades. In fact, with a worldwide increasing number of vehicles and a rising demand of emerging economies, demand will probably rise even harder. Transport fuel demand is traditionally satisfied by fossil fuel demand. However, resources of these fuels are running out, prices of fossil fuels are expected to rise and the combustion of fossil fuels has detrimental effects on the climate. The expected scarcity of petroleum supplies and the negative environmental consequences of fossil fuels have spurred the search for renewable transportation biofuels’ (Hill, Nelson, Tilman, Polasky & Tiffany, 2006). 

 

 

 

Biofuels appear to be a solution to substitute fossil fuels because, resources for it will not run out (as fresh supplies can be regrown), they are becoming cost wise competitive with fossil fuels, they appear to be more environmental friendly and they are rather accessible to distribute and use as applicable infrastructure and technologies exists and are readily available. Forecasts are that transport on a global scale will increase demand for conventional fuels with up to a maximum annual growth of 1.3% up to 2030. This would result in a daily demand of around 18.4 billion litres (up from around 13.4 billion litres per day in 2005) (The Royal Society, 2008). 

Biodiesel production is a very modern and technological area for researchers as an alternative fuel for diesel engines because of the increase in the petroleum price, its renewability and the environmental advantages. Biodiesel can be produced from renewable sources such as cooking oil, animal fat and used cooking oil. Currently, the cost of biodiesel is high as compared to conventional diesel oil because most of the biodiesel is produced from pure cooking oil. Extensive use of edible oils may cause other significant problems such as starvation in developing countries. 

 

 However, the cost of biodiesel can be reduced by using low cost feedstock such as animal fat and used cooking oil. It is estimated that the cost of biodiesel is approximately 1.5 times higher than that of diesel fuel due to the use of food grade oil for biodiesel production. 

 

The term “waste cooking oil” (WVO) refers to cooking oil which has been used in food production and which is no longer viable for its intended use. Waste cooking oil arises from many different sources, including domestic, commercial and industrial. Waste cooking oil is a potentially problematic waste stream which requires to be properly managed. The disposal of waste cooking oil can be problematic when disposed, incorrectly, down kitchen sinks, where it can quickly cause blockages of sewer pipes when the oil solidifies. Properties of degraded used frying oil after it gets into sewage system are conductive to corrosion of metal and concrete elements. It also affects installations in waste water treatment plants. Thus, it adds to the cost of treating effluent or pollutes waterways.  

 

The use of used cooking oil as feedstock reduces biodiesel production cost by about 60–70% because the feedstock cost constitutes approximately 70–95% of the overall biodiesel production cost. It is reported that the prices of biodiesel will be reduced approximately to the half with the use of low cost feedstock [Kemp, 2006; Radich, 2006; Anh et al., 2008]. Moreover used cooking oils can be a workable feedstock for biodiesel production as they are easily available. The use of non-edible plant oils when compared with edible oils is very significant because of the tremendous demand for edible oils as food, and they are far too expensive to be used as fuel at present. The land use for growing oilseeds as feedstocks for the biodiesel production competes with the use of land for food production.

BIOFUELS 

 

What are Biofuels 

Biofuels are energy carriers that store the energy derived from biomass, commonly produced from plants, animals and microorganisms and organic wastes. Biofuels may be solid, liquid or gaseous and include all kinds of biomass and derived products used for energetic purposes. Biofuels are renewable energy sources, meaning that fresh supplies can be regrown. 

Bioethanol, followed by biodiesel are the most produced types of biofuel. Figure 5.1.2 shows the world’s top ethanol and biodiesel producers in 2008. The United States (US) and Brazil are currently the leading ethanol producers and the expectations are that this will at least until 2018 remain so. The European Union (EU) is the world’s leading producer of biodiesel. 

 

  Biofuels for transportation primarily driven by government policies, world ethanol production for transport fuel tripled between 2000 and 2007 from 17 billion to more than 52billion litres, while biodiesel expanded eleven-fold from less than 1 billion to almost 11 billion litres .These fuels together provided 1.8% of the world’s transport fuel by energy value. 

 

                               

There are a variety of biofuels potentially available, but the main biofuels being considered globally are biodiesel and bioethanol. Bioethanol can be produced from a number of crops including sugarcane, corn (maze), wheat and sugar beet. Biodiesel is the fuel that can be produced from straight cooking oils, edible and non-edible, recycled waste cooking oils, and animal fat. The main producing countries for transport biofuels are the USA, Brazil, and the EU. Production in the United States was mostly ethanol from corn, in Brazil was ethanol from sugar cane, and in the European Union was mostly biodiesel from rapeseed. 

                                 

 BIODIESEL PRODUCTION 

 

 What is Biodiesel 

In the most general sense, biodiesel refers to any diesel fuel substitute derived from renewable biomass. More specifically, biodiesel is defined as an oxygenated, sulfur-free, biodegradable, nontoxic, and eco-friendly alternative diesel oil. Chemically, it can be defined as a fuel composed of mono-alkyl esters of long chain fatty acids derived from renewable sources, such as cooking oil, animal fat, and used cooking oil designated as B100, and also it must meet the special requirements such as the ASTM and the European standards. For these to be considered as viable transportation fuels, they must meet stringent quality standards. One popular process for producing biodiesel is transesterification. Biodiesel is made from a variety of natural oils such as soybeans, rapeseeds, coconuts, and even recycled cooking oil. Rapeseed oil dominates the growing biodiesel industry in Europe. In the United States, biodiesel is made from soybean oil because more soybean oil is produced in the United States than all other sources of fats and oil combined. 

 

           The injection and atomization characteristics of the cooking oils are significantly different than those of petroleum derived diesel fuels, mainly as the result of their high viscosities. 

 

    Modern diesel engines have fuel-injection system that is sensitive to viscosity change. One way to avoid these problems is to reduce fuel viscosity of cooking oil in order to improve its performance. The conversion of cooking oils into biodiesel is an effective way to overcome all the problems associated with the cooking oils. Dilution, micro emulsification, pyrolysis, and 

 

transesterification are the four techniques applied to solve the problems encountered with the high fuel viscosity. Transesterification is the most common method and leads to mono alkyl esters of cooking oils and fats, now called biodiesel when used for fuel purposes. The methyl ester produced by transesterification of cooking oil has a high cetane number, low viscosity and improved heating value compared to those of pure cooking oil which results in shorter ignition delay and longer combustion duration and hence low particulate emissions. 

 

 History of Biodiesel 

Dr . Rudolf Diesel invented the diesel engine to run on a host of fuels including coal dust suspended in water, heavy mineral oil, and, cooking oils. Dr . Diesel’s first engine experiments were catastrophic failures, but by the time he showed his engine at the World Exhibition in Paris in 1900, his engine was running on 100% peanut oil. Dr . Diesel was visionary. In 1911 he stated ‘‘the diesel engine can be fed with cooking oils and would help considerably in the development of agriculture of the countries, which use it’’. In 1912, Diesel said,’ the use of cooking oils for engine fuels may seem insignificant today. But such oils may become in course of time as important as petroleum and the coal tar products of the present time’’. Since Dr . Diesel’s untimely death in 1913, his engine has been modified to run on the polluting petroleum fuel, now known as ‘‘diesel’’. Nevertheless, his ideas on agriculture and his invention provided the foundation for a society fueled with clean, renewable, locally grown fuel. 

 

In the 1930s and 1940s, cooking oils were used as diesel substitutes from time to time, but usually only in emergency situations. Recently, because of increase in crude oil prices, limited resources of fossil oil and environmental concerns, there has been a renewed focus on cooking oils and animal fats to make biodiesel. Continued and increasing use of petroleum will intensify local air pollution and magnify the global warming problems caused by carbon dioxide. In a particular case, such as the emission of pollutants in the closed environment of underground mines, biodiesel has the potential 

 

to reduce the level of pollutants and the level of potential for probable carcinogens.   

                                

                                         Dr . Rudolf Diesel   

WHY BIODIESEL ?

  

It's Economical 

                Biodiesel can be produced by individuals on a small scale relatively inexpensively when compared to Petro diesel. Figures range anywhere from $0.40 a gallon to about $1.25 a gallon depending on the cost of materials required to make it. With prices that low, most people are able to save hundreds of dollars on their fuel bills. In some cases it even goes into the thousands of dollars. With savings like that, most people are able to recoup their initial investment on the equipment needed to make biodiesel within a matter of months. 

 

It's Renewable 

           Biodiesel has been touted far and wide for its renewable properties. Instead of making a fuel from a finite resource such as crude oil, Biodiesel can be produced from renewable resources such as organic oils, fats, and tallows. This means that it can be made from things that can be regrown, reproduced, and reused. So, if you need more, you can just grow another crop of seeds for the oil. 

 

It's Good For The Environment 

             When Biodiesel is used to power diesel engines, the emissions at the tailpipe are significantly reduced. Studies by the US National Renewable Energy Lab indicate drops in several key areas’ that help the environment. Carbon Dioxide, Hydrocarbons, and Particulate Matter (the black smoke from diesels) all are significantly reduced when Biodiesel is used. When used in older diesel engines such as indirect combustion diesels, the results are astounding. There was a reduction in the tailpipe emissions of nearly 90%. It also has a positive energy balance. 

 

It supports farmers 

          

           When Biodiesel is made from organic oils such as Canola, Soy, Peanut, or other domestically grown seed crops, it helps the farming community out. Because the oil used to make Biodiesel is "domestically grown", it keeps the money flowing to those that "grow" the feedstock. This continues to help out the renewable aspect of Biodiesel because this means more seed crops can be grown by local farmers. 

 

It reduces dependency on Crude Oil 

              When Biodiesel is used in place of Petro diesel, it reduces the amount of crude oil used up. This means that it helps to reduce our dependence on a limited resource and increases our use of renewable resources. We think that's a great step toward reducing our dependence on a fuel that may not be around forever. 

 

It's good for the engine 

 

               Biodiesel, unlike Petro diesel, has a much higher "lubricity" to it. This means that it's essentially "slipperier" than normal diesel fuel. With the added "lubricity" of Biodiesel, engines have been shown to experience less wear and tear when used on a regular basis. Also, because Biodiesel is less polluting, it means that it's easier on the engine. US Government Studies have shown that in some cases large fleets using Biodiesel have been able to go longer between oil changes because the oil stay's cleaner when Biodiesel is used. 

 

 It's the perfect alternative fuel 

 

              When compared to several other Alternative Fuels available, Biodiesel comes out way ahead. Most alternative fuels require changes to a vehicle to be used. Natural Gas & Propane require special tanks to be installed and changes to the fuel injection system must be made as well. Ethanol also requires specialized changes to the fuel injection system. Electricity requires a completely different engine. In most cases, once a vehicle undergoes the conversion necessary to run the alternative fuel, there's no going back. You either run the alternative fuel or you don't run the vehicle. 

 

BIODIESEL  ECONOMY 

 

                 The technical and economic advantages of biodiesel are that, it reduces greenhouse gas emissions because it reduces some exhaust emissions; it helps to reduce a country’s reliance on crude oil imports and supports agriculture by providing a new labor and market opportunities for domestic crops; it enhances the lubricating property; it is safer to handle, being less toxic, more biodegradable and it is widely accepted by vehicle manufacturers. 

 

The economic benefits of a biodiesel industry would include value added to the feedstock, an increased number of rural manufacturing jobs, increased income taxes, increased investments in plant and equipment, an expanded manufacturing sector, an increased tax base from plant operations and income taxes, improvement in the current account balance, and reductions in health care costs due to improved air quality and greenhouse gas mitigation. 

 

The major economic factor to consider for input costs of biodiesel production is the feedstock, which is about 80% of the total operating cost. Other important costs are labour, methanol and catalyst, which must be added to the feedstock. The cost of biodiesel fuels varies depending on the base stock, geographic area, variability in crop production from season to season, the price of crude petroleum and other factors. Biodiesel can be over double the price of petroleum Diesel. The high price of biodiesel is in large part due to the high price of the feedstock. However, biodiesel can be made from other feedstocks, including used cooking oil, beef tallow, pork lard and yellow grease. Biodiesel has become more attractive recently because of its environmental benefits. With cooking oils used as raw material, the viability of a continuous transesterification process and recovery of high quality glycerol as a biodiesel by product are primary options to be considered to lower the cost of biodiesel.  

 

 However, there are large amounts of low cost oils and fats such as restaurant wastes and animal fats that could be converted to biodiesel. The problem with processing these low cost oils and fats is that they often contain large amounts of free fatty acids (FFA) that cannot be converted to biodiesel using an alkaline catalyst. A review of 12 economic feasibility studies shows that the projected costs for biodiesel (BD) from oilseed or animal fats have a range US $0.30 0.69/l, including meal and glycerin credits and the assumption of reduced capital investment costs by having the crushing and/or esterification facility added onto an existing grain or tallow facility. Rough projections of the cost of BD from cooking oil and waste grease are respectively, US$0.54–0.62/l and US$0.34–0.42/l. With pre-tax Diesel priced at US$0.18/l in the US and US$0.20–0.24/l in some European countries, BD is, thus, currently not economically feasible, and more research and technological development will be needed. 

 

Biodiesel is a technologically feasible alternative to Petro diesel, but nowadays biodiesel costs 1.5 to 3 times more than fossil diesel in developed countries. Biodiesel is more expensive than Petro diesel, though it is still commonly produced in relatively small quantities (in comparison to petroleum products and ethanol). The competitiveness of biodiesel to Petro diesel depends on the fuel taxation rates and policies. Generally, the production costs of biodiesel remain much higher than those of Petro diesel. Therefore, biodiesel is not competitive with Petro diesel under current economic conditions. The competitiveness of biodiesel relies on the price of the biomass feedstock and costs associated with the conversion technology. 

                           

 Biodiesel production economic balance 

 

Several (non-technological) limiting factors have been stopping until now the development of the bio-diesel industry. These limiting factors are feedstock prices, bio-diesel production costs, crude oil prices and taxation of energy products. 

 

 Feedstock prices 

 

No matter the technological process adopted for bio-diesel manufacturing, the largest share of production cost of bio-diesel is the feedstock cost. The feedstock cost is the major obstacle to the market feasibility of bio-diesel. Rape-seed, used in bio-diesel sector, covers around half of the non-food area under set-aside scheme. 

 

 Biodiesel production costs 

 

The estimated costs for biodiesel can be split up into fixed and variable costs. Fixed costs come from extracting the cooking oil from seed and processing this cooking oil into biodiesel. These costs include manufacturing, capital, and labour costs. Glycerol and protein meal for livestock feed are by products that might help to offset the cost of biodiesel production. The sale of these by products is considered fixed income. Rape-seed price (Pr) is considered as а variable one. It is also considered that manufacturing 1 litre of bio-diesel needs 2.23 kg. rapeseed on average basis. By assuming the reference rapeseed price of 16.84 rupees/kg a net cost of 43.82 rupees/L biodiesel is obtained. 

Taxation of energy products 

 

There is no harmonized European policy, either for fossil fuels or for bio-fuels. Each Member State implements own domestic regulations, inside the EU framework for taxation of energy products. The minimum levels of taxation are modified depending on whether these motor fuels are used for certain industrial or commercial purposes. The proposal refers to: agriculture and forestry; stationary motors; plant and machinery, used in construction; civil engineering and public works; vehicles, intended for use off the public roadway; passenger transport and captive fleets, which provide services to public bodies. 

 

  

 

EXPERIMENTAL PART 

 

 The production of biodiesel from rapeseed oil experiment 

                                           

                            

 Pressing of Rapeseed oil :

 

                     1.2 Kg of, seven- year- old rapeseed, was pressed which gave 500 ml of Rapeseed oil and the pressed oil was filtered using filter paper for 24 hours. 50 ml of the filtered oil was used for the determination of the free fatty acid percentage. 

 

 The determination of free fatty acid :

 

10 grams of the filtered rapeseed oil was put in 250 ml Erlenmeyer flask, and then 50 ml of diethyl ether and ethanol were added. Stirring was done until the oil was completely dissolved in the solvent mixture. A burette was filled with about 10-15 ml of ethanolic KOH solution, 3 4 drops of phenolphthalein (1% in ethanol) and a magnetic stir bar were given to the solution in the Erlenmeyer flask, and then the KOH solution was added to the mixture (mixture titration).When the colour of the mixture changed, the mixture was left another 30 second to be sure of the new colour.  

 

A formula was used to determine the concentration of free fatty acid in rapeseed oil: 

 

% free fatty acid = a * avg. mol. wt. / 10 * E 

where: 

a: volume [ml] of KOH * 0.1 [mol / ml] 

avg. mol. wt.: 314 g / mol 

E: initial weight in grams 

 

A computer program of Biodiesel, shown in figure 8.2, was used to determine the amounts of addition of methanol and KOH for esterification.

Transesterification: 

 

The rapeseed oil was heated up to 30 0C, and was put on a stir, the KOH was dissolved in the Methanol and slowly the methanol-KOH was allowed into the oil in drops and the oil was left to the next day. 

 

Fuel analytics: Determining some properties of Rapeseed oil, Diesel and two types of Biodiesel; one produced in the Lab and the other from the gas station; density, kinematic viscosity, lower calorific value and oxidation stability .

                            

 Introduction 

 

                       A reliable operation of combustion engines is only possible, when important characteristics and substances of content of the fuel are defined. The specification of fuel quality by the use of consistent parameters and testing methods also enables fuel improvement, if necessary. Moreover, the comparison of engines’ emission behaviour is only possible when certified fuels (reference fuels) are used. Finally a defined fuel quality is basis for trading fuels. 

 

Technical Details and Standards of diesel and biodiesel 

 

                      There are three existing specification standards for diesel & Biodiesel fuels (EN590, DIN 51606 & EN14214). EN590 (actually EN590:2000) describes the physical properties that all diesel fuel must meet if it is to be sold in the EU, Czech Republic, Iceland, Norway or Switzerland. It allows the blending of up to 5% Biodiesel with 'normal' DERV - a 95/5 mix. DIN 51606 is a German standard for Biodiesel, is considered to be the highest standard currently existing, and is regarded by almost all vehicle manufacturers as evidence of compliance with the strictest standards for diesel fuels.  EN14214 is the standard for biodiesel now having recently been finalized by the EuropeaThin layer chromatography: 

 

A good way to check for impurities; how many different compounds are in a sample, very small quantities of the samples are placed on the special TLC plates. The plate is put in a container with a solvent or solvent mixture, the solvent runs up the plate and will separate the different kinds of molecules based on polarity differences and size differences. 

 

There are two phases of Thin layer chromatography a stationary phase (a solid, or a liquid supported on a solid) and a mobile phase (a liquid or a gas). 

 

The mobile phase flows through the stationary phase and carries the components of the mixture with it. Different components travel at different rates. The stationary phase in this case is silica gel coated on a thin piece of rigid plastic. The mobile phase in this case is a mixture of solvents hexane and ethyl acetate in a specific ratio (v/v).    

Fuel analytics: Determining some properties of Rapeseed oil, Diesel and two types of Biodiesel; one produced in the Lab and the other from the gas station; density, kinematic viscosity, lower calorific value and oxidation stability.

 

 

  Kinematic Viscosity measurement: The Ubbelohde viscometer 

 

                        Viscosity refers to a fluid’s resistance to flow at a given temperature. A fuel that is too viscous can hinder the operation of an engine. Kinematic viscosity measures the ease with which a fluid will flow under force. It is different from absolute viscosity, also called dynamic viscosity. Kinematic viscosity is obtained by dividing the dynamic viscosity by the density of the fluid. If two fluids with the same absolute viscosity are allowed to flow freely on a slope, the fluid with higher density will flow faster because it is heavier. The density of biodiesel varies depending on its feedstock. Longer and straighter chains (saturated fats) tend to have higher density than shorter and unsaturated molecules. Kinematic viscosity allows comparison between the engine performance of different fuels, independent of the density of the fuels. Two fuels with the same kinematic viscosity should have the same hydraulic fuel properties, even though one fuel may be denser than the other. The highest acceptable kinematic 

 

viscosity for bio diesel as specified in D6751 is 6.0. EN 14214, the biodiesel standard for the European market, specifies a viscosity limit for biodiesel of 3.5–5.0 mm 2/s. If a batch of biodiesel does not meet this specification, the viscosity can be corrected by blending it with a fuel that has a lower or higher viscosity. 

 

The Ubbelohde type viscometer, shown in figure 9.6, is a measuring instrument which uses a capillary based method of measuring viscosity. The device was invented by the German chemist Leo Ubbelohde (1877-1964). The Ubbelohde viscometer is a u-shaped piece of glassware with a reservoir on one side and a measuring bulb with a capillary on the other. A liquid is introduced into the reservoir then sucked through the capillary and measuring bulb. The liquid is allowed to travel back through the measuring bulb and the time it takes for the liquid to pass through two calibrated marks is a measure for viscosity. The Ubbelohde device has a third arm extending from the end of the capillary and open to the atmosphere. In this way the pressure head only depends on a fixed height and no longer on the total volume of liquid. The advantage of this instrument is that the values obtained are independent of the concentration.  

                                              

 

It shows the experimental results of kinematic viscosity for rapeseed oil, two types of biodiesel and diesel fuel. It could be noticed from the table that the rapeseed oil has the highest viscosity among the other fuels because vegetable based oils tend to be fairly viscous and don’t flow too easily. Also, it could be noticed that diesel has lowest viscosity. Biodiesel of the two types has higher viscosity than diesel specially the one produced in the lab because not all of rapeseed oil was converted completely to biodiesel, it had a little amount of rapeseed oil and it’s known that rapeseed oil has high viscosity (mm2/s) 

 

 Density Measurement: Hydrometer and Pycnometer 

Density is the weight per unit volume. Diesel fuels have higher densities and therefore it gives more energy than that of the petrol. The densities of the cooking oils are higher, but during the transesterification process the density is decreased, however they are denser than the diesel fuels and thereby they are an efficient alternative. 

 

 Hydrometer 

                       A hydrometer is an instrument used to measure the specific gravity (or relative density) of liquids; that is, the ratio of the density of the liquid to the density of water. A hydrometer is usually made of glass and consists of a cylindrical stem and a bulb weighted with mercury or lead shot to make it float upright. The liquid to be tested is poured into a tall container, often a graduated cylinder, and the hydrometer is gently lowered into the liquid until it floats freely. 

 

       The point at which the surface of the liquid touches the stem of the hydrometer is noted. Hydrometers usually contain a scale inside the stem, so that the specific gravity can be read directly. A variety of scales exist, and are used depending on the context. 

 

 

                                            

 

 Pycnometer 

                                             A pycnometer is a small flask with a glass stopper. A capillary opening which runs along the length of the stopper makes it possible to fill the pycnometer completely- that is, without leaving a bubble of air in the flask. Table shows the experimental results of Density for rapeseed oil, two types of biodiesel and diesel fuel. It could be noticed for rapeseed oil and biodiesel produced in the lab, density was measured by hydrometer and pycnometer, it can be noticed that rapeseed oil has the highest density because cooking oils are denser in their chemical structure. Also, it could be noticed that diesel and biodiesel have close densities, with higher density for biodiesel due to the fact that biodiesel is made out of cooking oil and that it is not converted to 100% biodiesel. 

                                    

 

 Heating value Measurement: 

The Bomb Calorimeter 

 

                                         Heating value or Heat of combustion is the amount of heating energy released by the combustion of a unit value of fuels. The most important determinants of the heating value are the moisture content. It is because of this, that the purified Biodiesel is dried. The moisture content of the Biodiesel is low and this increases the heating value of the fuel.   A bomb calorimeter is a type of constant-volume calorimeter used in measuring the heat of combustion of a particular reaction. Bomb calorimeters have to withstand the large pressure within the calorimeter as the reaction is being measured. Electrical energy is used to ignite the fuel; as the fuel is burning, it will heat up the surrounding air, which expands and escapes through a tube that leads the air out of the calorimeter. When the air is escaping through the copper tube it will also heat up the water outside the tube. The temperature of the water allows for calculating calorie content of the fuel. The calorimeter gives the value of the high heating value or the GROSS (or higher) calorific value for a fuel. The net calorific value is then obtained by subtracting the latent heat of the water present from the gross calorific value. The latent heat of vaporization of water is 2.5MJ/kg. 

 

Table shows the experimental results of Lower heating value for rapeseed oil, two types of biodiesel and diesel fuel. It could be noticed that diesel has the highest heating value, which means that the energy released of diesel combustion is the highest, while biodiesel comes in the second place of amount of energy released and the last one is the rapeseed oil.

              

 Measuring the oxidation stability 

Because of the chemical structure of fatty acid methyl esters (FAME), they age more quickly than fossil diesel fuels. Therefore it was considered to include a limit for oxidation stability in the existing quality standard for biodiesel. Oxidative stability is an important parameter in the characterization of fats and oils. 

 

Transesterification of cooking oils with methanol produces the methyl esters of the fatty acids (together with glycerol as a by product). These have only a limited shelf-life as they are slowly oxidized by atmospheric oxygen. The resulting oxidation products can cause damage to combustion engines. This is why oxidation stability is an important quality criterion for biodiesel, which needs to be regularly determined during production. With the Rancimat this determination can be carried out quickly and simply, and the value is given in hours. The fuel sample is heated up to 110⁰ C, compressed air is supplied through the fuel into a flask with distilled water. Conductivity of the distilled water is measured; when it raises the fuel begins to deteriorate. The point at which the conductivity curve bends as shown in Figure 7.2.6.1 (the red line) is defined as the oxidation stability. 

 

The oxidation stability of diesel is measured differently from rapeseed oil and biodiesel. Diesel is heated up to 95°C for 16 hours and exposed to 3 liter per hour of pure oxygen (accelerated aging), because of the aging resin will be formed in the diesel (deterioration of diesel), the concentration of resin in the diesel is measured and the value is given in gram per cubic meter. 

               

 

 CHNS Elemental Analyzer (EA): 

CHNS elemental analysers provide a means for the rapid determination of carbon, hydrogen,nitrogen and sulphur in organic matrices and other types of materials. They are capable of handling a wide variety of sample types, including solids, liquids, volatile and viscous samples, in the fields of pharmaceuticals, polymers, chemicals, environment, food and energy. The analysers are often constructed in modular form such that they can be set up in a number of different configurations to determine, for example, CHN, CHNS, CNS or N depending on the application. 

               

 It  shows an example of the results of carbon, hydrogen, nitrogen and sulphur contents for biodiesel produced in the lab of the elementary analyser device. Three results of three samples of biodiesel are shown in the figure. The samples were made and put into the elementary analyser, to make sure that the device is working well and that good results are given and that was shown from the close results that were got for the three samples. Then these results are entered into the calorimeter device to get the lower heating value of the biodiesel which is shown in table 9.6 as 37510 kJ/kg. 

 

 The Emission testing experiment for rapeseed oil, low sulfur diesel fuel and biodiesel (from gas station). 

Equipment used:

1-Engine used: 

Tractor Diesel engine of type Kubota 05 Series D1105-E3B, it is a three cylinder swirl chamber engine with a total displacement of 1.1 litre. The engine is used for driving a generator to produce electricity; waste heat of the engine is used for heating (co-generation unit). Electric and thermal power of co-generation unit respectively are 5 and 12 Kw, respectively.  

                       

 

2- MLT 4 Multi- Component Gas Analyzer 

MLT 4 Multi-Component Gas Analyzer is a multi-component, multi-method analysis using infrared, ultraviolet, thermal conductivity, paramagnetic and electrochemical sensor technologies. Housed in a 19-inch enclosure (thermostatically-controlled option), 

Kubodiesel engine the MLT 4 Gas Analyzer can measure up to five gas components by combining the different technologies into one unit.   

                                                                                      

3- Total Hydrocarbon Analyzer (THC) : 

The Total Hydrocarbon Analyzer is designed especially for mobile use at various sites and operating conditions both for continuous and short monitoring. Features of the total hydrocarbon analyser include measuring ranges from 1 ppm to 100,000 ppm, internal air supply and a patented miniature heated sensor block with a flame ionisation detector controlled up to 240° C, making it possible to measure in steam saturated gases. The instrument is suitable for compliance to national reference measuring methods and regulations for emission measuring and for the efficiency control of thermal, catalytic, biological and activated carbon exhaust air purifying plants and other emission sources, permitting control of these processes.  

 

 4- BRIGON - Smoke Tester:     

 

The BRIGON-Smoke is a device for determining the smoke number. It is easy to handle, lightweight and reliable instrument. The smoke tester forces a gas sample to cross the filter paper and leave a soot spot, which is then compared with smoke scale to determine smoke number. High smoke number is an obvious symptom of incomplete combustion and may have various reasons, as well as serious consequences (air pollution, soot disposition on heat exchange surfaces, fuel waste, etc.) The contents of this smoke tester include smoke tester, filter paper, smoke scale and lubricant oil .   

                            

 

                                The diesel engine of type Kubota 05 Series D1105-E3B was turned on, the engine’s speed was1500 rpm and the electric load was 5 Kw at full load. The first fuel was used was the rapeseed oil, the average time for every fuel was 15 minutes in the engine. Measurements of the emissions were taken after the temperatures of the engine’s cooling water and exhaust were stable. Three measurements of hydrocarbons were taken at three different times as shown in table 8.9. Then three samples of ash or soot were taken on a filter paper and ash or smoke number was measured by a detecting device. The gas analyser took measurements every 5 seconds for 15 minutes and the file of the emission measurements was saved on a special computer program to calculate the mean values. The same procedure was used for diesel and biodiesel fuels. 

                           Table shows three different readings of the total hydrocarbons at three different times for rapeseed oil, diesel and biodiesel. It can be noticed that there is no big difference in the readings for every fuel. Also, it can be noticed that the rapeseed oil has the highest readings of the total hydrocarbons while the biodiesel has the lowest readings 

 

                               which is reasonable. For the smoke number, it can be noticed that rapeseed oil also has the highest readings, while diesel and biodiesel readings are close to each other, but the biodiesel smoke number  for biodiesel is a little bit higher than diesel. 

 

                                        It  shows the mean values of the resulted emissions for every fuel that were measured by the gas analyser. For SO2, O2 and CO2 it can be noticed that the values for every fuel are almost similar. For NOx, it can be noticed that the rapeseed oil has the lowest value of NOx, while diesel has the highest value. The higher NOx emissions may be due to the higher cetane rating and oxygen content of the fuel, so that atmospheric nitrogen is oxidized more readily. For CO, it is noticed that biodiesel has more value of CO than diesel and higher CO emission means that the combustion was not done completely.

              

CONCLUSION AND RECOMMENDATION 

 

                              In a world where every action must be weighed against its demerits, where everything should be balanced between power and the environment, in a world like today, where petroleum reserves are becoming limited and will eventually run out and the critical issue of oil peak and the environmental concerns, all have prompted deeper research into the area of alternatives to fossil fuels which are biofuels such as biodiesel and bioethanol. Biodiesel has become more attractive recently because of its environmental benefits and the fact that it is made from renewable resources. Biodiesel is briefly defined as the mono alkyl esters of cooking oils or animal fats. Biodiesel is the best candidate for diesel fuels in diesel engines. It burns like petroleum diesel as it involves regulated pollutants. So it necessary to implement the use of biodiesel over the current petroleum and gasoline because of all the merit and advantages it brings forth to the table. In comparison to petroleum and gasoline, biodiesel beats its competitors in all categories of toxic substance emissions and poses close to no threat to the environment. What's more, instead of increasing the carbon dioxide levels in the atmosphere, the overall production and use of biodiesel consumes more carbon dioxide than it emits, thus making it a valuable tool in preventing global warming. 

 

Not only does petroleum diesel harm our environment through emissions of toxic substances, but it also has negative effects on us physically. Many health problems and illnesses have been traced back to emissions from petroleum diesel. These emissions have been related to many cases of cancer, cardiovascular and respiratory disease, asthma and infections in the lungs. By using biodiesel in the place of petroleum diesel, not only will we be helping the environment with a much better alternative, but we would be significantly reducing many health risks. 

 

 The fact that most biodiesels are domestically produced means that by using more of it, the market of biodiesel would actually stimulate the economy, reducing a country’s dependence on foreign oil imports. Also, the implementation of biodiesel is extremely easy and requires little or no modifications to the typical diesel engine, making it a very easy and smooth transition. 

 

When we weigh the advantages of biofuel against its disadvantages, it is clear that it brings more than it takes away because biofuels are easily available from common biomass sources, carbon dioxide cycle occurs in combustion, they are very environmentally friendly, and they are biodegradable and contribute to sustainability (Puppan, 2002). 

 

It is true that commercial food are used to make biodiesel but if there is a surplus of it, why not put the excess to better use. Not only does it match its rivals in energy output, it also reduces the damage done to the world. 

 

The production of biodiesel from waste cooking oil offers a triple-facet solution: economic, environmental and waste management. The new process technologies developed during the last years made it possible to produce biodiesel from recycled frying oils comparable in quality to that of virgin cooking oil biodiesel with an added attractive advantage of being lower in price. Thus, biodiesel produced from recycled frying oils has the same possibilities to be utilized. 

 

 Recommendations: 

Further research should be done on the following areas: Nowadays bio-diesel cost is 1.5 to 3 times higher than the fossil diesel cost because the largest share of production cost of bio-diesel is the feedstock cost. Therefore, biodiesel is not competitive to fossil diesel under current economic conditions, where the positive externalities, such as impacts on environment, employment, climate changes and trade balance are not reflected in the price mechanism. However, biodiesel can be made from other feedstocks of low cost oils and fats such as restaurant waste and animal fats that could be converted into biodiesel. The problem with processing these low-cost oils and fats is that they often contain large amounts of free fatty acids (FFA) that cannot be converted into biodiesel using an alkaline catalyst (Demirbas, 2003; Canakci and Van Gerpen, 2001). 

 

Important operating disadvantages of bio-diesel in comparison with fossil diesel are cold start problems and the lower energy content. This increases fuel consumption when biodiesel is used (either in pure or in blended form) in comparison with application of pure fossil diesel, in proportion to the share of the bio-diesel content. Taking into account the higher production value of bio-diesel as compared to the fossil diesel, this increase in fuel consumption raises in addition the overall cost of application of bio-diesel as an alternative to fossil diesel.