1.1 Background of Study
The replacement of gasoline with alternative fuel has been an important issue to the energy and sector Environmental Protection Agency (EPA) has resulted to increase in the price of petroleum fuel due to environmental threats from engine exhaust emissions, fossil fuel depletion, global warming and energy concerns (G?r? et al., 2009). The implementation of alcohols as alternatives for petrol in spark ignition (SI) engines has been investigated comprehensively and was observed that, low carbon monoxide emissions, enhanced octane number and fuel efficiency was achieved. / Despite its advantages, ethanol production has been known to economically inefficient and not commercial in terms of volumes to meet up with the huge energy market compared to petroleum gasoline.
Experimental studies have shown that when blending ethanol with gasoline as its simple chemical structure, high octane number and oxygen content, and accelerated flame propagation was achieved and resulted in enhancing motor engine efficiency, torque, and power. In addition the resulting brake specific fuel consumption (BSPC) was higher than that of gasoline (Masum et al., 2013b; Ko? et al., 2009). In many countries such as those listed above, governments have already been mandate the integration of ethanol with gasoline. The Environmental Protection Agency (EPA) issued a waiver that authorizes the incorporation of up to 15% ethanol into gasoline for cars and light pickup trucks made in 2001 onwards (Wald, 2010).The US Renewable Fuel Standard mandates the production of up to 36 billion gallons of ethanol and advanced bio-fuels by 2022 (Rabobank, 2012). To cope up with increased demand for ethanol, alcohols with increased carbon numbers can be utilized as heightened substitutes because, the implementation of ethanol as fuel ingasoline engines is mainly limited by its low heating value (LHV).
Further studies has shown that, alcohol-gasoline blend emitted less CO and HC but more NOx and CO2 than pure gasoline. Studies informs that, multiple alcohol-gasoline blends also emit more acceptable levels of CO and HC than the ethanol-gasoline blend alone. Alcohols with low carbon content (e.g. C1, C2, and C3) contain high levels of oxygen. Hence, relatively less of these alcohols are required to meet the targeted oxygen percentage than alcohols with high carbon content (e.g., C4 and C5).
Researchers and observers did not blend alcohols with less carbon content such as methanol in specific percentages with gasoline and octane number boosters such as addition of iso-octane to develop and improve blendproperties. No research has been conducted considering improvement fuel properties of the multi alcohol-gasoline blend. There is a lack of research on optimization of fuel properties of multiple alcohol-gasoline blends with octance number boosters, using a low cost, time efficient and advanced process modelling packages such as ASPEN Hysis, a product by ASPEN-One Technologies to achieve optimized petroleum blend. As a result, this project seeks to enhance the properties of gasoline compared to those in the markets and other blends.
1.2 Statement of Problem
When cars burn gasoline, they would ideally burn it perfectly and create nothing but carbon dioxide and water in their exhaust. Unfortunately, the internal combustion engine is not perfect. The incomplete combustion of gasoline yields injector/valve deposits of carbon, poor mileage and engine performance, raised toxic emission (Carbon monoxide, Nitrogen Oxides and unburned hydrocarbons). Also, the poor chemical stability of gasoline in SI engines is a problem and has raised considerably great concerns by researchers in this area.
This project seeks to enhance the properties of gasoline from Naphtha with different alcohol in proportions, to improve S.I engines performance using process simulation approach.
1.3 Aim of Project
This work is aimed at developing a refinery flow process methodology to investigate on the effect of proportional addition of multi component alcohol to gasoline properties such as RON, MON, true boiling point (TBP), oxygen content etc. from Naphtha.
1.4 Specific Project Objectives
Obtain Naphtha from refinery process,
Develop a computer flow process model of gasoline production,
Improve gasoline octane number by introducing proportional volume of Ethanol into the gasoline flow production process,
Develop gasoline ethanol octane number relationship for each proportion and compare with literature,
Evaluate the economics of the project using Aspen Economic Evaluator.
1.5 Significance of Study
Studies have proven that, blending gasoline with Ethanol reduces toxic gases emissions up-to 30%, cleans the car engine and dirt from pipes and chambers. It also acts as anti-knocking agent results in decreasing engine knocking and comparing with petrol, ethanol burns cleaner and completely.
2.1 Literature Review
2.1.2 Octane Enhancing Petrol Additives/Products
The move to harmonise Australian fuel standards with those of Europe willhave a profound effect on the manufacture and supply of petrol. Amongst otherfactors, harmonisation requires an increase in motor octane. This is the subjectof this Review.
As well as increasing octane, harmonisation will require limits to be placed onthe levels of aromatics and olefines in the petrol. These components have anaturally high octane and the new limits will make the manufacture of highoctanepetrol more difficult. Whilst this can be achieved, it will only be doneso at an increased cost to the motorist and an increased cost to the environment.
In order to ameliorate these costs, octane-enhancing additives may prove usefulto Australian refiners and importers. The availability, cost and environmentalimpact of these additives are reviewed.
Current researches are concerned with the production of petrol, which has no other use than asa fuel for transport. Petrol comprises a mixture of many thousands of differenthydrocarbon compounds plus additives that may contain other elements. Veryfew are non-toxic or unhazardous in some way or other. Although used in largequantities by the motorist, the general public rarely comes into contact withpetrol. It is always confined to sealed vessels, and modern-filling techniquesminimises fugitive emissions and splashes.
Like the components of petrol, each of the octane-enhancing additives presentenvironmental and health issues. All of the problems are solvable within theboundaries of fuel production, storage, transport and distribution.
Fuel harmonisation is occurring across the world. Whilst the primary aim is tofacilitate the introduction of better emission standards for vehicles, there will beanother effect, namely an increase in trade of fuels as opposed to basestocksand refinery intermediates.
Because fuels will be produced to similar standards across a range of countries(eg. South Asia), there will be an opportunity for refiners to benefit fromeconomies of scale and supply several markets with petrol. This will serve tobenefit the motorist by holding down price rises that would otherwise occur asa result of the increased costs of production of the better quality fuel.
Although there will be opportunities for the larger and more modern Australianrefineries, the increased cost of producing the higher quality fuels may createdifficulties for the smaller and older refineries. Market share currently suppliedby the latter refineries may be lost to interstate refineries and imports.
Because of the large volume use of petrol, and to minimise shipping costs, it isshipped in relatively large vessels. To permit effective trade and preventshortages, we have to guard against using Australian fuel standards as a meansof unfairly discriminating against imported product.
The danger is the tendency to ban specific petrol components as a reaction toadverse media coverage or to pacify local political pressure. Obviously localbans of specific components is contrary to fuel harmonisation.
A specific case in point is the ether additive MTBE. This is the most widelyused octane-enhancing additive, but is currently under suspicion in the US as acontaminant of water supplies. Because of the contamination of vessels,banning MTBE (and similar ethers) could effectively present a barrier toimporting lower cost petrol.
Further, banning ethers (or any other additive) would require extensive testingof product. Because of the scale of import, refusal of entry of a contaminatedvessel, would result in disruptions to the local petrol supply chain, inevitablyincreased prices for the motorist, and potentially shortages and rationing.
Taking all of these points into consideration, and aiming to achieve theoptimum outcome for the motorist, refiner, importer and the environment, thedirection of the recommendations is to facilitate maximum flexibility in thesupply of petrol to the proposed new, higher-octane petrol standards.
184.108.40.206 Review on Findings
It is technically feasible for Australia to adopt Euro-3 petrol standards withoutresorting to octane enhancers. However, this will constrain the industry toproducing petrol high in aromatics.Mass production of high octane 98 RON and Euro-4 fuel will probably requireoctane enhancers.s
Suitable octane enhancers are alcohols, ethers and organometallics such as theadditive MMT.Of the alcohols, methanol is to be avoided. Ethanol is the alcohol of principalinterest. It is used in petrol in Australia and elsewhere. Ethanol can beproduced from biomass, but to remain competitive would require a subsidy -ethanol is currently free of excise.
However, there are serious issues with the use of ethanol, which remain to beaddressed. These include air toxicity and water contamination. It is highlylikely that it will be difficult, if not impossible, for ethanol – petrol blends tomeet Euro-3 specifications from the standpoint of summer RVP (60 kPa limit).
Waiving this limit for ethanol would undermine the reasoning for a low RVPvalue in Euro-3 and Euro-4.
The use of higher alcohols (propanols, butanols) will be constrained by supplybut may be able to make an occasional contribution in selected instances.
Of the ethers, MTBE is the preferred oxygenate of world oil industry. It iswidely used in Europe, the USA and the Far East. It is not currently used inAustralia.The controversy surrounding the use of MTBE is a consequence of the failureto properly control petrol transport and storage. All oxygenates (includingethanol) are likely to suffer a similar level of concern if they were widely used.
The MTBE controversy may lead to the phase out of MTBE in the USA. Thisis likely to severely disrupt world markets for oxygenates and petrol feedstocks.It will cause a major worldwide reappraisal of the approach to octane.
It is doubtful if Europe could adopt the new standards (Euro-3 and Euro-4)without the use of MTBE.
Other ethers (TAME, ETBE, DIPE) are likely to be useful in occasionalcircumstances. Their use is likely to be constrained by supply. Their use islikely to be marred by the MTBE controversy.
The use of the manganese additive MMT is highly controversial but hasgrowing acceptance in the refining industry. MMT may be useful in producinglead replacement petrol and to achieve the lower Euro-4 aromatics level.
Optimum results may be obtained by using a mixture of additives so as toameliorate the deficiencies of each of the additives.
2.1.2 Effects of Alcohol-Gasoline Blend on Fuel properties
It can be pooled combined with gasoline as its simple chemical structure, high octane number and oxygen content, and accelerated flame propagation (Masum et al.,2013b). Many experimental studies have ensured that ethanol enhance the engine efficiency, torque, and power. However, its brake specific fuel consumption (BSFC) is higher than that of gasoline (Ko? et al., 2009). In many countries, governments have already been mandate the integration of ethanol with gasoline. The Environmental Protection Agency (EPA) issued a waiver that authorizes the incorporation of up to 15% ethanol into gasoline for cars and light pickup trucks made in 2001 onwards (Wald, 2010).
The US Renewable Fuel Standard mandates the production of up to 36 billion gallons of ethanol and advanced bio-fuels by 2022 (Rabobank, 2012). To cope up with increased demand for ethanol, alcohols with increased carbon numbers can be utilized as heightened substitutes because the implement of ethanol as fuel in gasoline engines is mainly limited by its low heating value (LHV).
Hence, additional low-LHV fuel must be generated to match a certain power level (Demirbas, 2009a). Alcohols with high carbo numbers, such as propanol and butanol, have a higher LHV than ethanol. On the other side, all of these alcohols can be produced from coal-derived syngas that is a renewable source (Campos- Fernandez et al., 2013). Moreover, the concept of biorefinery forhigher-alcohol production is to combine ethanol formation via fermentation with the transformation of this simple alcohol intermediateinto higher carbon number alcohols (Olson et al., 2004).
Higher carbon numbered alcohols, those having lower RON, can also be applied in gasoline engine if ethanol is added, as ethanol has higher RON. Thus, multi-alcohol gasoline may provide better outcomes in fuel property as well as engine output. Some authors have emphasized on the potentiality of fuel properties using blends of multiple alcohols with gasoline and got better fuel properties than conventional ethanol gasoline blend (Lawyer et al., 2013a, b).
Some observations and rigorous studies have analyzed the casual relationship of different type of alcohol as a partial alteration of gasoline in SI engine. Gravalos et al. (2013) integrated approximately 1.9% methanol, 3.5% propanol, 1.5% butanol, 1.1% pentanol,
and variable concentrations of ethanol with gasoline in a singlecylinder gasoline engine. A total of 30% alcohol was incorporated into the gasoline. The alcoholdgasoline blend emitted less CO and HC but more NOx and CO2 than pure gasoline. In this paper, multiple alcoholegasoline blends also emit more acceptable levels of CO and HC than the ethanoldgasoline blend.
Yacoub et al. (1998)integrated methanol, ethanol, propanol, butanol, and pentanol with gasoline in an engine and explained and analyzed its performance and emissions. Each alcohol was blended with gasoline containing 2.5% and 5% oxygen. The alcohol-gasoline blend displayed better BTE, knock resistance, and emissions than gasoline, but its BSFC was higher. Alcohols with low carbon content (e.g. C1, C2, and C3) contain high levels of oxygen. Hence, relatively less of these alcohols are required to meet the targeted oxygen percentage than alcohols with high carbon content (e.g., C4 and C5). Alcohol percentage and properties differed for the variation in blends. Thus, different alcohol-gasoline blends cannot be compared properly under optimized oxygen concentrations.
Gautam et al. (2000) prepared six alcohold gasoline blends with various proportions of methanol, ethanol, propanol, butanol, and pentanol that total 10% alcohol. The alcohol-gasoline blends emitted lower brake specific CO, CO2, and NOx than pure gasoline. However, these experts and researchers did not blend specific volume percentages of alcohol or consider fuel properties.
This study, as an observation, put its utmost effort to emphasize on the development of various physicochemical properties using multiple alcohols (C2 to C6) at different ratios compared to that of the conventional ethanol-gasoline blend. To optimize the properties of multiple alcohol-gasoline blends, properties of each fuel were measured first. An optimization tool of Microsoft Excel Solver was used for obtaining the optimum blend. Using optimizing tool, three optimum blend ratios were selected which possessed maximum heating value (MaxH), maximum research octane number (MaxR) and maximum petroleum displacement (MaxD). These blends were used for testing in a four cylinder gasoline engine at the wide open throttle condition with varying speeds and compared obtained outcomes with that of E15 (15% ethanol and 85% gasoline) as well as gasoline. Optimized blends have shown higher brake torque and brake thermal efficiency (BTE) but lower brake specific fuel consumption (BSFC) than E15. MaxR, MaxD and MaxH blends produced mean 4.4%, 1.8% and 0.4% increased BTE and mean 4.39%, 1.8% and 2.27% lower BSFC than that of E15. On the other hand, MaxR, MaxD, MaxH and E15 reduced 4.46%, 8.37%, 12.4% and 17.2%, mean CO emission and 4.5%, 11.81%, 8.19% and 16% mean HC emission respectively than that of gasoline. NOx emission of optimized blends was higher than gasoline. However, MaxR, MaxD, MaxH reduced 4%, 14.57% and 20.76% NOx than that of E15.