Fuels have dominated the way the world operates for decades; with a rising demand for fuel becoming constantly more predominant. Their uses are vast, making them versatile and in high demand around the world. But since most common fuels like diesel and petrol are fossil fuels, the availability of such fuels is decreasing rapidly. Hence alternatives to these fuels are being developed and used worldwide. These alternatives include biofuels. Biofuels are defined as “a hydrocarbon that is made BY or FROM a living organism that we humans can use to power something.” (biofuel.org.uk, 2010) Most biofuels are made using forms of biomass, including algae, sugar cane, seeds, oil, fats etc. (biofuel.org.uk, 2010) Biodiesel is a biofuel alternative to …show more content…
(biofuel.org.uk, 2010) Combustion ensues when a fuel is reacted with air. Complete combustion occurs when all of the bonds in a molecule are broken, releasing the maximum amount of energy. Complete combustion is referred to as the excess. However, in reality this rarely occurs. Incomplete combustion ensues when there is a reduced amount of oxygen available - hence not all of the bonds are broken. Incomplete combustion is referred to as the limiting. (BBC, 2014) Figure 1 – Endothermic and Exothermic Reactions Source: (Beychok, 2012)
Heat of formation measures the theoretical amount of energy released in reaction. (Helmenstine, 2014) It is calculated using the formula on the screen. Heat of combustion measures the experimental amount of energy released in a reaction. (Oliver, 2014) It can be calculated using the formula on the screen.
The heat of formation of dodecane (C12H26) – traditional diesel – was calculated for the complete combustion to equal:
ΔHf = 154.8798KJ/g
The heat of combustion of dodecane (C12H26) – traditional diesel – was calculated for the complete combustion to equal:
ΔHc = 87.95KJ/g
The heat of formation of dodecane (C12H26) – traditional diesel – was calculated for the incomplete combustion to equal:
ΔHf = 91.6KJ/g
The heat of combustion of dodecane (C12H26) – traditional diesel – was calculated for the incomplete combustion to equal:
ΔHc = 48.71KJ/g
The energy released in the
A year before Charles and Frank made their first car, Rudolf Diesel patented the design for diesel powered combustion engine. He believed that this would revolutionize the industry, because diesel fuel harbored a higher concentration of energy per gallon (132×106 vs 155×106 joules, gasoline and diesel respectively; in terms of energy density). The problem is that the exhaust is typically dirtier due to the much oilier nature of the fuel.
This simple experiment is carried out to show the difference in the enthalpy change of combustion between two fuels, hexane and methanol. These fuels are individually weighed before and after used as heat source to heat water in a calorimeter. The result is used to find out amount of heat transferred by the fuel, amount of fuel used and the enthalpy change of combustion.
It was desired to compare a theoretical value of enthalpy of combustion to a literature value. To do this, the theoretical value was calculated using a literature value for the heat of sublimation of naphthalene, the heat of vaporization of water and average bond energies, given in Table 1 of the lab packet.1 Equations (1) and (5) were used to calculate the theoretical enthalpy of combustion of gaseous naphthalene, where n was the number of moles, m was the number of bonds, and ΔH was the average bond energy:
Fuel is usually consistent of octane, ethyl benzene, Trimethylpentane, toluene, and brutane. The reactions of 3.51kg of oxygen to one kilogram of fuel causes the production of 1.42kg pf water and 3.09kg of carbon dioxide. Simply written out, it would form an equation similar to C8H18+O2+CO2+H2O —> CO2+H2O. Dismally, this doesn’t work as a proper equation, as one would find it impossible to balance out. The balanced equation would be closer to C8H18+O2 —> CO2+H2O. Now that one is able to balance the equation, we’ll multiply the carbon dioxide and water by eight and nine respectively. Now there are too many oxygen on the right side of the equation (product). We move to the left side of the equation (reactant) and change the O2 to 25/2O2. Balanced, the equation is C8H18+25/2O2 —> 8CO2+9H2O. In terms of heat through energy, this equation can be converted to [(8 x -393.5) + 9 x -241.8)] - 250.1. What this means is for each time the reactant produces the CO2+H2O mixture, -5270kj of energy are produced.
The Molar Heat of Combustion of a substance is the heat liberated when 1 mole of the substance undergoes complete combustion with oxygen at standard atmospheric pressure, with the final products being carbon dioxide gas and liquid water. (Ref. “Conquering Chemistry, Roland Smith, 2005”)
Motor vehicle use is now generally recognised as the source of more air pollution than any other single activity in cities around the world. The internal combustion engine of a vehicle produces power by burning fuel and changing the chemical energy of fuel into heat energy. The heat energy is then converted into mechanical power. Cars and trucks do not burn all of the fuel that goes into the combustion chamber. In fact, most vehicles only burn about 85% of the fuel and as the vehicle gets older less and less fuel is burned. It is this unburned fuel that produces some harmful products which are discharged from the engine and become air pollutants.[iv] Therefore, an engine’s fuel system, and its emission controls are closely interrelated. That is why attention is given to the requirements of emission control in the design and operation of all parts of the fuel system in a vehicle.
Methanol as a biofuel is an environmental friendly substitute to pure diesel and can be obtained from biomasses. Use of biofuels such as methanol for combustion process is associated with positive environmental impacts. Using pure methanol or blended with diesel fuel in automotive has been proposed by researchers. In this paper, methanol was injected into combustion chamber of a ISM 370 HD diesel engine and exhaust emissions of this engine which took advantage of pure methanol were evaluated by using AVL FIRE CFD code software at four engine speeds (1200, 1400, 1600 and 1800 rpm). Additionally, influences of EGR mass fraction and various injection timings were investigated. For validation of simulation, in-cylinder mean pressure and rate of
Combustion takes place when fuels react with oxygen to produce heat (E-inst.com, 2015). The heat created by the burning of fuel is used in the operation of equipment such as boilers and furnaces, as well as heat being produced, when reactants undergo combustion CO2 (carbon dioxide) and H2O (water) are formed as byproducts of the exothermic reaction (E-inst.com, 2015).
The basic difference between a diesel engine and a gasoline engine is that in a diesel engine, the fuel is sprayed into the combustion chambers through fuel injector nozzles just when the air in each chamber has been placed under such great pressure that it’s hot enough to ignite the fuel spontaneously.
Combustion is the chemical process of a combustion reaction in which a fuel burns with the aid of an oxidiser to yield a particular product. When an alkanol is burned, the product will consist of carbon dioxide, water and heat, as shown in figure 2.
Diesel is also very harmful to your body. On the Material Safety Data Sheet diesel has some very shocking information listed for it.
Diesel and gasoline engines have been each other’s competition since the 1930’s when the first diesel run car was produced. There is one main mechanical difference between these two engines; a gasoline engine ignites the gasoline with spark plugs, a lighter of sorts, and the diesel engine ignites the diesel by compressing it so much that it spontaneously combusts. Although there are a few other types of engines now, such as hybrid or electric, diesel is still superior to these.
Engineering: [a] diesel engine is an internal combustion engine in which the chemical energy of fuel is transformed into thermal energy of the cylinder charge, in consequence of the self-ignition and combustion of fuel in the engine cylinder after compression of the air charge in the cylinder (p1
Biofuel can be used as substitutes for conventional fuels e.g. petro fuels. Mainly, biofuel contains hydrogen and methane which are particularly
Thus, it is for commercial acceptance the peroxide. The use of DTBP produces substantial reductions in the soluble organic fraction of the based cetane improvement additives must be stable, thermally and oxidative, at actual use temperatures. The thermal stability of DTBP was demonstrated by determining the effects of heating on the treated fuels and also by measurement of the decomposition rates in a low sulfur diesel fuel! A fuel treated with DTBP showed no statistically significant loss in cetane number after heating for 100 hours at 92°C. The half-life for DTBP at 70°C in diesel fuel is in excess of 10,000 hours, with greater than 97% of the additive remaining after nearly 700 hours. Even at lOOnC, the half-life of DTBP in diesel fuel is over 300 hours. Even though the rate of thermal decomposition of the peroxide is five to ten times faster than the nitrate, the peroxide additive is very stable under typical fuel system temperatures. Stability of DTBP was demonstrated by the standard ASTM methods. Both the accelerated oxidative stability test (D274)12 and the long term storage stability test (D4625)13 did not show any gum formation in most of the diesel fuels tested. In some, inherently unstable