CHAPTER TWO
REVIEW OF RELATED LITERATURE
This chapter embarks on reviewing theoretical and empirical literatures. Under theoretical section the study reviewed literatures to define key terms such as fuel, fuel adulteration, and mitigation to fuel adulteration.
Further the study reviewed literatures about the underlying issues linked to the research topic such as causes of fuel adulteration, consequence of fuel adulteration, diesel and gasoline physico-chemical properties, parameters to automotive fuels (gasoline and diesel) quality, automotive fuels (gasoline and diesel) quality specification, importance of fuel quality, fuel quality control methods, ASTM quality control, fuel quality test kits, analytical methods on controlling fuel adulteration, and theorizing how to halt fuel adulteration.
Finalize theoretical review by theorizing how to mitigate fuel adulteration and developing theoretical framework. After meanwhile, the study also reviewed empirical literatures. At the end the study led in to a conceptual framework consists of various ideas that are entrenched in existing theories, sources and experiences mostly influenced by the context of the study.
2.1. Theoretical Review
2.1.1. Conceptualization of Key Terms
2.1.1.1. Fuel
A fuel (from Old French feuaile, from feu fire, ultimately from Latin focus fireplace, hearth) is a substance that may be burned in air (or any other oxidant-containing substance), i.e. that so quickly reacts with oxygen that heat and light is emitted in the form of a sustained flame (Ofondu 2011). Fuel is a combustible substance, containing carbon as main constituent which on proper burning gives large amount of heat which can be used economically for domestic and industrial purpose (Nyabaro, Kituyi and Okemwa 2021).
Its flash point is the minimum temperature at which the liquid fuel produces a sufficient concentration of vapor above which it forms an ignitable mixture with an air and able to produce a flame (Kwao-Boateng, et al. 2024).
The primary or main source of fuels is coals and petroleum oils, the amount of which are decreasing day-by-day. Based on their occurrence fuels are classified as primary fuel secondary fuels. Primary fuels are fuels which are found in nature as such they are used. These fuels are wood, coal, petroleum, natural gas. On the other hand secondary fuels are those which are derived from primary fuel. Again these fuels are charcoal, coke, kerosene, diesel, petrol, and producer gas (Murago 2010).
Most of the foregoing secondary fuels are the products of refinery process of petroleum. In treatise of Robinson (2012) Potter (1987) defined petroleum refining as the process of separating the many compounds present in crude petroleum.
The basic refinery operations include; distillation process, thermal cracking, catalytic process, treatment, formulation and blending (OTM, 2003). The major refinery products are; gasoline, kerosene, diesel and other refinery products (Kwao-Boateng, et al. 2024).
Gasoline is a mixture of hundreds of hydrocarbons many of which have different boiling points. By definition gasoline is a volatile flammable liquid hydrocarbon mixture, used as a fuel especially for internal combustion engines. Motor gasoline is the predominant transportation energy source, and will continue to hold this position in the near future (De Almeida e Silva 2020).
In Nyabaro, Kituyi, & Okemwa (2021) article Speight (2002) opined that gasoline boils and distills over a range of temperatures, unlike a pure compound, water, for instance, that boils at a single temperature. Gasoline boils between 30°C and 202°C for one to obtain a distillation curve (Ofondu 2011).
Gasoline is one of the most widely used energy sources. In 2018 gasoline made up 46% of all the petroleum products used [4] and represented 54% of the transportation sources. According to Lea, (2019) motor gasoline is, in fact, the predominant transportation energy source and will continue to hold this position at least until 2040 (De Almeida e Silva 2020).
By definition, gasoline is a mixture of volatile, flammable hydrocarbons derived from petroleum. Products derived from oil tend to have extremely complex matrices. Gasoline is characterized by having three main species in its composition: paraffins, olefins and aromatics (Benvenutti 2022).
The gasoline product as a transportation fuel, as we know it, is a blended mixture, having a predefined octane value. This means that the hydrocarbons mixture must have a boiling point temperature range between 20oC and 200oC, i.e. the carbon range of its constituents should be from C4 to C12 (Ismayir and Dawood 2012)
Regarding to diesel; it is known as automotive gas oil. According to Cedre (2006) diesel is produced from petroleum, and is usually referred to as petro diesel to distinguish it from diesel obtained from other sources such as biodiesel (Murago 2010).
Diesel fuel is a complex mixture of hydrocarbons with the main groups being paraffins, napthenes and aromatics. Organic sulfur is also naturally present. Diesels emit high levels of oxides of nitrogen and particulates. Achieving very low levels of NOX and PM therefore require exhaust treatment (Manaye 2018). Lean NOX catalysts, selective catalytic reduction (SCR), NOX storage traps with periodic reduction, filter traps with periodic burn-off, and oxidation catalysts with continuous burn-off are evolving technologies. To reduce PM and NOX emissions from a diesel engine, the most important fuel characteristic is sulfur
2.1.1.2. Automotive Fuels (Gasoline and Diesel)
The term “automotive fuel” means liquid fuel of a type distributed for use as a fuel in any motor vehicle (Ismayir and Dawood 2012). The two most common engines utilize gas oil and gasoline fuels for this purpose. Automotive Gas oil, also known as diesel, is generated from crude distillation process with boiling range of approximately 86-428°F.
On the other hand; Diesel fuel is a blend of light and heavy distillates and has an American Society for Testing and Materials (ASTM) boiling range of approximately 350–675°F (Robinson 2012).
Diesel fuel is a mixture of thousands of hydrocarbons obtained by distillation of crude oil that are blended with some additional components, from upgrading and conversion processes. Additives are used to provide specific performance requirements according to its usage. Diesel is used to feed diesel engines, which operate according to the diesel cycle (Benvenutti 2022).
Automotive Gas Oil, or AGO, is the name given to fuel intended for use in road vehicles (trucks, buses, vans and cars) powered by diesel engines. AGO is used in two main types of vehicle: Heavy-duty vehicles, such as trucks and buses, light-duty vehicles, such as vans and passenger cars.
Diesel engines are widely used in heavy-duty vehicles. Such vehicles are frequently operated in fleets and are re-fuelled centrally with fuel delivered direct from the supplier. In the light-duty vehicle sector, recent advances in engine design now also allow light-duty diesel engines to compete with gasoline engines on performance grounds.
On the other hand, gasoline is a refined product of petroleum consisting of a mixture of hydrocarbons, additives, and blending agents. The composition of gasoline varies widely, depending on the crude oils used, the refinery processes available, the overall balance of product demand, and the product specifications.
The typical composition of gasoline hydrocarbons (% volume) is as follows: 4-8% alkanes; 2-5% alkenes; 25-40% isoalkanes; 3-7% cycloalkanes; l-4% cycloalkenes; and 20-50% total aromatics (0.5-2.5% benzene) (IARC 1989).
IARC (1989) further added that additives and blending agents are added to the hydrocarbon mixture to improve the performance and stability of gasoline. These compounds include anti-knock agents, anti-oxidants, metal deactivators, lead scavengers, anti-rust agents, anti-icing agents, upper-cylinder lubricants, detergents, and dyes. According to Mehlman (1990) at the end of the production process, finished gasoline typically contains more than 150 separate compounds although as many as 1,000 compounds have been identified in some blends
2.1.1.3. Fuel Adulteration
Fuel adulteration is defined as the illegal or unauthorized introduction of foreign substance into fuels (gasoline, kerosene, diesel and other refinery products) with the result that the products do not conform to the requirements and specifications of the products (Gawande and Kaware 2013 ).
Adulteration is defined as the illegal introduction of a lower in state, lesser distant substance into a higher-level, senior substance so as we get obtained mixture which does not contain the original specification or properties of real product. The distant substances are also called adulterants, which when presented degrade the nature of the item (Madankar, Patil and Chakole 2019).
Fuel adulterations are different kinds. Among these are blending relatively small amounts of distillate fuels like diesel or kerosene into automotive gasoline. It would be also blending variable amounts (as much as 30 percent) of gasoline boiling range hydrocarbons such as industrial solvents into automotive gasoline (World Bank 2020).
It might be also Blending small amounts of -spent waste industrial solvents such as used lubricants -which would be costly to dispose of in an environmentally approved manner – into gasoline and diesel. Blending kerosene in to diesel, often as much as 2O-30 percent would be considered as adulterant; because, it is heavier fuel oils in to diesel fuels (World Bank 2020). For instance, in case of gasoline; the adulterated gasoline can be made by adding organic solvents, aromatic compounds, detergents and other similar compounds (De Almeida e Silva 2020).
The higher sulfur level of kerosene (for example, the permissible level in India is 0.25 percent by weight as against 0.10 percent for gasoline) can deactivate the catalyst and lower conversion of engine-out pollutants (Gawande and Kaware 2013 ).
Specific to diesel; high-level adulteration of low sulfur (for example, 0.05 percent) diesel fuel with higher-level sulfur kerosene can cause the fuel to exceed the sulfur maximum (De Almeida e Silva 2020). In addition, high-level adulteration of low Sulfur diesel fuel with more elevated amount Sulfur lamp oil can make the fuel surpass the Sulfur greatest.
On the other hand; high-level adulteration of low Sulfur diesel fuel with more elevated amount Sulfur lamp oil can make the fuel surpass the Sulfur greatest. Impetus can be deactivated because of huge centralization of lamp fuel and lower transformation of motor out toxins (Gauci and Arkoudeas 2020).
The adulteration in fuel may likewise cause change in octane number of the fuel being utilized, which thusly may result in harm to the Engine. Blending diesel with lamp oil can leave hurtful stores in motors (Kwao-Boateng, et al. 2024).
2.1.1.4. Consequence of Fuel Adulteration
The very term consequentia was in use in exactly this sense since Boethius (5th-6th Century): the topic itself occupied a prominent position in earlier traditions. But no treatises or chapters with this name seem to have been written before the 14th Century. Very early, rather ‘primitive’ treatises: two anonymous and Burley’s De consequentiis. Second stage – more elaborate treatises, but external validation for consequences (middles, reworked Topics): Ockham’s Summa Logicae, Burley’s De Puritate Artis Logicae (Ashworth 1973)
Later the continental tradition – sophisticated treatises, where formal consequences are defined substitutionally: Buridan, Albert of Saxony, Pseudo-Scotus, Marsilius of Inghen. Recently, the British tradition – characterized by the definition of formal consequence in terms of containment of the consequent in the antecedent: Richard Billingham, Ralph Strode, Richard Lavenham.
Buridan’s definition of consequence “A proposition is antecedent to another when it is related to it [the other] in such a way that it is impossible for things to be in whatever way the first signifies them to be without their being in whatever way the other signifies them to be, when these propositions are put forward together.” (Buridan and Hubien 1976).
What is consequence? Is it a conditional sentence? Is it a logical relation between contents? Is it an inference, i.e. the act performed by somebody of drawing a conclusion from premises? (Carbonell 2011)
Some literatures consider consequence as of a statement in which from one given thing another follows. In this case ‘it follows’ means the same as ‘it is said to follow’. Others consider it as of the division into good and bad, or valid and invalid. According to Kesler (1623) a valid consequence, is a statement in which one proposition is inferred from another by a legitimate deduction, in such a way that the consequent is dependent on the antecedent (Ashworth 1973).
Further, the scholar added that a valid consequence is a statement in which one proposition is inferred from another by a legitimate deduction, in such a way that the consequent is dependent on the antecedent.
While adulteration in fuel damages the vehicle, it becomes more dangerous because it generates significant health hazards too. Adulterated petrol and diesel emit dangerous levels of hydrocarbons, carbon monoxide, oxides of nitrogen, particulate matter and can cause increased emissions of air toxic substances. Adulterating gasoline with kerosene causes increase in emissions, as kerosene is more difficult to burn than gasoline and this result in higher levels of HC, CO and PM (Gawande and Kaware 2013 ).
When the adulterated diesel is used in vehicles it may produce harmful toxic gases which contain higher levels of HC, CO. This decline the environment and ultimate reason of air pollution.
High-level adulteration of low Sulfur diesel fuel with more elevated amount Sulfur lamp oil can make the fuel surpass the Sulfur greatest. Impetus can be deactivated because of huge centralization of lamp fuel and lower transformation of motor out toxins (Madankar, Patil and Chakole 2019).
The adulteration in fuel may likewise cause change in octane number of the fuel being utilized, which thusly may result in harm to the Engine. Blending diesel with lamp oil can leave hurtful stores in motors. The adjustment in octane rating may enact an issue called motor thumping (Sarıkoç 2022).
Gasoline adulteration increases exhaust emission of hydrocarbons that is both harmful to the environment and to human health. If such adulteration reaches high levels it can also be hazardous to the vehicle’s internal combustion level (Ismayir and Dawood 2012).
Kerosene is more difficult to burn than gasoline, so that its addition results in higher levels of HC, CO and PM emissions even from catalyst-equipped cars. Specific to diesel; the addition of heavier fuels increases in-cylinder deposits and fouls injectors (De Almeida e Silva 2020).
Adulterated gasoline can be hazardous to both human health and the vehicle’s internal combustion system. In fact, it has been proven that gasoline adulteration can lead to increased tailpipe emissions of hydrocarbons, carbon monoxide and oxides of nitrogen. This increase further harms air quality and is therefore detrimental to human health. Adulteration can also origin malfunction of the engine as well as safety problems (Benvenutti 2022).
On the other hand; high-level adulteration of low Sulfur diesel fuel with more elevated amount Sulfur lamp oil can make the fuel surpass the Sulfur greatest. Impetus can be deactivated because of huge centralization of lamp fuel and lower transformation of motor out toxins (Gauci and Arkoudeas 2020).
The adulteration in fuel may likewise cause change in octane number of the fuel being utilized, which thusly may result in harm to the Engine. Blending diesel with lamp oil can leave hurtful stores in motors (Kwao-Boateng, et al. 2024).
2.1.2. Causes of fuel adulteration
As the fuel prices are increases, people try to reduce the prices by mixing, combining cheaper hydrocarbons to highly taxed hydrocarbons. There are different products have having the comparable qualities and costumers are unable to differentiate because of lack of tools required for identification because different products having same properties (Madankar, Patil and Chakole 2019).
The adulteration of the gasoline is brought by the different tax regime imposed by various countries making some of the hydrocarbon products inexpensive and consequently, a good choice as the adulterant (Pathak and Singh 2019).
In case of Asia financial incentives arising from differential taxes are generally the primary cause of fuel adulteration (World Bank 2020) . Particularly, in reference to India; as fuel prices rise, the public transport driver cuts costs by blending the cheaper hydrocarbon into highly taxed hydrocarbon (Gawande and Kaware 2013 ).
In India, the adulteration of petroleum products is primarily done due to the major cost disparity between goods. The government has decided to fix the kerosene subsidy that the Union Budget would provide for in the current fiscal at Rs. 26/liter. To the contrary, Diesel costs Rs. 74 /liter and Petrol costs Rs. 85 /liter (as of 20/Nov/ 2018).Various method used to evaluate the fuel adulteration are Sensor based technique. This paves the way for Illegal activities. Actually, illegal activities in the retail business are a global phenomenon and fuel adulteration is one of the major problems for the customers (Madankar, Patil and Chakole 2019).
2.1.3. Diesel and Gasoline Physico-Chemical Properties
This study has reviewed literatures about Diesel and gasoline physico-chemical properties. As part of physico-chemical properties; this study considered the following issues i.e.; color, molecular weight, physical state, boiling point, odor, solubility, vapor pressure, flammability limit, theoretical air/fuel ratio, Specific ************* , API at 60F, viscosity, density, Cetane number (CN), evaporation characteristics, flash point closed cup, cold flow characteristics, heating value of fuel, water content, n-alkanes, branched alkanes, and S (% wt.)
Gasoline color, molecular weight, and physical state are colorless to pale grown, 108a, and liquid respectively. On the other hand, molecular weight to diesel is 184.25. In addition physical state to diesel is liquid. Boiling point to gasoline is ranged from 39 to 204oC. On the other hand, boiling point to diesel is 180–360 °C (356–680 °F).
Odor to gasoline is gasoline odor. Gasoline is insoluble in water at 20oC; meanwhile, it is soluble in organic solvents such as chloroform, benzene, alcohol, and ether. Gasoline vapor pressure is ranged in between 465mmHg to 773mmHg. Gasoline flammability limit and explosive limit are 1.4-7.4% and 1.3 – 6% respectively. To gasoline theoretical air/fuel ratio: A=14.5 kg air by kg fuel.
Diesel Specific ************* is 0.8333. In contrary gasoline Specific ************* is. Diesel API at 60F is 38.31. In contrary gasoline API at 60F is.
Viscosity is a measure of resistance to flow of a liquid due to internal friction of one part of a fluid moving over another, under the force of gravity. This is a critical property because it affects the behavior of fuel injection (Texaco, Chevron, and Caltex 2021). Viscosity to gasoline is 0.5*10-6 m2/s at 20 ºC. On the other hand, Viscosity (cSt at 40 °C) to diesel is 4.53.
Next to viscosity, this study has also reviewed literatures about density. The volumetric mass density of a substance is its mass per unit volume. Particularly, the air-fuel ratio and energy content within the combustion chamber are influenced by fuel density (Sarıkoç 2022). Density to gasoline is 0.7-0.8g/cm3. On the other hand density to diesel is 0.862g/cm3.
After stopping a while; his study has also reviewed literatures about Cetane Number (CN). It is the main indication of the auto-ignition and combustion quality characteristics of the fuel used in a diesel engine. It affects cold start, combustion stability and noise. A higher CN generally decreases engine cranking time (the time before the engine reaches “starter off”) by decreasing the ignition delay (Niculescu and Clenci 2018). Cetane Number (CN) to diesel is 49.06. On the other hand, Cetane number = 5…20, meaning that gasoline has a relative large time-lag between injection in hot air and auto ignition, although this is irrelevant in typical gasoline applications (spark ignition).
After reviewing literatures about CN; the study also read a lot of stuffs about evaporation characteristics (EC). EC influences the spray structure and affects the preparation of air–fuel mixture under different engine load conditions. The volatility characteristics are described by using the vapor pressure and distillation curve which are affected by intermolecular interactions (Sarıkoç 2022).
Next to EC, this study has also reviewed literatures about flash point (FP) closed cup. Flash Point closed cup temperature is the minimum temperature (subjected to barometric pressure 101, 3 kPa) at which the fuel will ignite (flash) on application of an ignition source under specified conditions. Flash point to gasoline is at -46oC. On the other hand, Flash point to diesel is 61℃. Auto ignition temperature to gasoline is 280-486oC.
It is used to classify fuels for transport and storage according to hazard level; minimum flash point temperatures are required for proper safety and handling of the fuel (Gauci and Arkoudeas 2020).
After stopping a while; his study has also reviewed literatures about Cold Flow Characteristics (CFC). One of the most fundamental quality criteria for compression ignition engine fuels is the cold flow characteristics, which are primarily dictated by: (1) fuel distillation range, mainly the light-end volatility; (2) hydrocarbon composition: content of paraffins, naphthene, aromatics; (3) use of cold flow additives (Benvenutti 2022).
The mechanism of cold flow properties consists in at low temperature engine operation, fuel gelling takes place, which results in crystallization of the molecules of the liquid. For crystallization to occur, the molecules of the liquid must generate sufficient thermodynamic force by the strong intermolecular force of interaction (Sarıkoç 2022). Cold filter plugging point (°C) to diesel is -4.66. In addition cloud point to diesel is 0.66.
After reviewing literatures about Cold Flow Characteristics (CFC); the study also read a lot of stuffs about heating value (HV) of fuel. The heating value of a fuel (HV) is the maximum amount of heat that can be released upon the complete combustion of a quantity unit of fuel. The heating value is expressed in units of heat per quantity unit of fuel: the quantity unit of fuel for solid and liquid fuels is kg and for gasses is considered to be m3 N (normal cubic meter) or mol (kmol). So, the units of heating value are: kJ/kg, kJ/m3 N, kcal/kg, kJ/Kmol, etc. (Texaco, Chevron, and Caltex 2021). To gasoline Average Eurosuper values are: HHV=45.7 MJ/kg, LHV=42.9 MJ/kg.
Next to heating value (HV) of fuel, this study has also reviewed literatures about water content. The fuel should be clear in appearance and free of water, which can plug fuel filters at negative temperatures, leading to engine fuel starvation. Water accelerates oxidation, increases corrosiveness and promotes microbial growth. The unit for water content could be [mg/kg] (Benvenutti 2022).
Lastly the researcher has also reviewed literatures about the chemical properties of gasoline and diesels. Gasoline has a total n-alkane 17.3. It has also a total branched alkane 32.0. Gasoline has also a total of cycloalkanes of 5.0. It has also total olefins 1.8. Gasoline has also a total of aromatics 30.5. It has also S (% wt.) is 0.04. On the other hand, diesel has 0.57.
2.1.4. Parameters to Automotive Fuels (Gasoline and Diesel) Quality
The following parameters are the major criteria in the production of automotive fuels (gasoline and diesel) with respect to their performance. These are: octane number, thermal efficiency, volatility of the gasoline, and engine deposits. The common tests to check the quality of finished products cover the following: specific gravity,
ASTM distillation, sulfur content, Reid vapor pressure, copper corrosion, and gum content (Gauci and Arkoudeas 2020). Among the most important parameters in the manufacture of fuel products (gasoline, diesel, kerosene and petrol) are their resistance to ‘knocking’. This resistance is expressed as an ‘octane number’ (Ismayir and Dawood 2012).
Regarding to thermal efficiency; since around 1980s engine manufacturers have been incorporating knock sensors to the engine electronic management system to continuously adjust the ignition timing. This development allows the timing of the spark to occur in advance of the piston reaching the top of its travel (Kwao-Boateng, et al. 2024).
The maximum engine efficiency is produced with this timing control measured and adjusted by the computer control of fuel to air ratio. Further development and testing of individual engine design sets optimum criteria for fuel octane number of the fuel and air ratio for lean mixture combustion (Gauci and Arkoudeas 2020).
As far as engine deposits are concerned; they affect fuel efficiency and emissions. Deposits are of particular concern in the carburetor, fuel injectors, inlet valves, and combustion chamber (Ofondu 2011)r. These deposits are essentially fine carbon granules which are formed by high inlet valve temperatures, air flow inconsistencies, and minor oil contamination.
Regarding to The Reid Vapour Pressure (RVP); it is an important physical property of volatile liquids. It is the pressure a vapor exerts on its surrounding. It is an indirect measure of evaporation. The volatile property of PMS is of paramount importance to spark ignition engines (Ismayir and Dawood 2012).
Concerning of specific gravity; Density ASTM D 1298—Density, relative density (specific gravity), or API gravity of crude petroleum and liquid petroleum products is determined by hydrometer method. In respect to volatility of the gasoline; it is an important property of gasoline is its volatility (Gauci and Arkoudeas 2020).
It must be volatile enough to provide the engine capable of starting at the lowest temperature expected in its service. At too low volatility the engine would have difficulty starting and would be prone to stalling in service. On the other hand too high volatility would cause excessive vapor which in turn would cause vapor lock in pipes and pumps (Ismayir and Dawood 2012).
Key provisions are 1) fuel specifications for petrol, diesel, and blended bio-components used on-road; 2) Intended to limit air pollutants, including: Sulfur oxide (SOx), Metallic emissions (in particular lead), Particulate matter, Hydrocarbons, Polycyclic aromatic hydrocarbons (PAH), benzene, Reduced requirements for gasoil used in non-road mobile machinery (sulfur, some metallic additives); 3) Compatibility of fuels with engines and after-treatments; 4) Fuel parameters regulated: 18 for petrol, 6 for diesel; 5) Blending limits for certain biofuels: Fatty Acid Methyl Ester (FAME) generally limited to7% in diesel, Ethanol limited to10% in petrol; 6) Fuel quality monitoring
Gasoline quality is defined in terms of a range of quality parameters. The properties of gasoline as other fuels may be classified into three categories; operational properties such as fuel octane number properties determining the durability and chemical stability or the chemical composition of fuels such as fuel Octane Number (ON) (Ismayir and Dawood 2012). Gasoline performance characteristics are significantly influenced by the ON, RVP; lead content, sulfur content, existent gums and stability. Among other parameters, fuel performance characteristics are also significantly influenced by (ON) and evaporation characteristics. On the other hand; the Engine Manufacturing Association (EMA) requires a minimum of 50cetane for optimal performance.
2.1.5. Automotive Fuels (Gasoline and Diesel) Quality Specification
Automotive Fuels specification is a mechanism by which producers and users of fuel product identify and control the properties necessary for satisfactory and reliable performance. A stated physical and chemical property of product, a manufacture supplying should satisfy the need of end users and fulfill requirement of OEM and regulatory bodies (Lawrence 2018).
The objective of fuel quality specification encompasses 1) Environmental and health protection in relation to fuel used in road transport and non-road mobile machinery; 2) Air quality; 3) Functioning of the internal market for transport fuels and vehicles; and 4) Reduction of life cycle greenhouse gas emissions from transport fuels.
2.1.6. Importance of Fuel Quality
Fuel quality has direct impact on exhaust emissions leading to pollution. It impacts engine performance and fuel consumption. Fuel quality alleviates the problem linked to high sulfur – corrosion and wear of the engine. It also halts the problem associated with high heavier end leads to soot / smoke / PM in tailpipe. Fuel quality also curbs the problem linked to all catalyst /EC technologies adversity (Dhuha and Dawood 2012).
2.1.7. Fuel Quality Control Methods
In case of European diesel fuel standard (EN590), 7% of the FAME conformed to the neat FAME standard (EN14214) can be blended in diesel fuel. Therefore, it is essential to guarantee the quality of neat FAME for end user acceptance (Kwao-Boateng, et al. 2024).
In Germany and Austria, Arbeits gemeinschaft Qualitäts management Biodiesel e.V. (AGQM) was established in 1999. Twenty-three FAME producers, accounting for 90 % of FAME production in both countries, and eight trading companies join the AGQM. Filling stations, which sell neat FAME or FAME-blended diesel fuel, are the AGQM’s member.
The main objectives of the AGQM are as follows; 1) observance of legal and customized requirements of the fuel properties, 2) Provision of a consistently high Biodiesel quality, 3) Avoidance of technical problems caused by fuel, 4) creation of all user’s trust in biodiesel.
In Japan, the Ministry of Economy Trade and Industry (METI) is responsible for fuel quality in the consumer market. In accordance with the Japan fuel standards law, METI is obligated to monitor registration of gas stations, where all gas stations are required to register with METI. Blenders of Biofuel (ethanol and/or FAME) with petroleum based fuels are required to register with METI (Benchmarking of Biodiesel Fuel Standardization in East Asia Working Group 2010).
METI need to develop fuel quality standards (both mandatory and voluntary). Require gas stations to report quality sampling test of gasoline every ten days or annually if its supply chain is approved by METI. METI should monitor fuel quality at the pump, which can be outsourced to four registered testing organizations.
2.1.8. ASTM Quality Control
ASTM quality control encompasses Quality control (QC) procedures, Test samples, reporting, reference materials, Reference materials (RM) stability, Proficiency test, Control samples, written policy defining how long data should be retained; Calculations: data review, validation, and retesting (ASTM 2000).
Regarding to Quality control (QC) procedures; there should be a document that summarizes the QC program. As far as test samples are concerned; the test or analysis sample should be traceable to the submitter by a formal chain of custody from intake through the analysis or test procedures. There should also be a permanent log containing all important information about a sample. Each sample should also be a given a unique laboratory identifier which should appear on all subsamples and documents (ASTM 2023).
Regarding to reporting; all data reported to the customer should be traceable to the initial receipt of the sample. The evaluator should select a few final reports at random and determine that sample and data traceability is adequate. All worksheets or similar documents should also include the sample identifier. Personnel who carried out the activities should be identified on the documents to provide a source for information should a problem be suspected. Between any two documents reviewed, there should be no deviation of information identifying the sample or preceding test results (ASTM 2002).
Concerning of reference materials; it should be tested according to a specific schedule. For all test calibrations, data (including operator’s identification) should be maintained in a permanent log and kept current in statistical form or control chart form or both so that anyone can see immediately what the condition of standardization is for a given test. Written policies should be defined at what point of nonconformance action needs to be taken to correct equipment or procedures to assure that a test procedure is in calibration (ASTM 2000).
As far as Reference materials (RM) stability is concerned; it should be stable material of appropriate top size with an appropriate matrix and, when used as primary standards. It should also be traceable to Certified Reference Materials (CRMs). It is also desirable to compare results from a new sample with the old one before the new one is used as the standard. Permanent records should be maintained of such actions in the log book (ASTM 2002).
Regarding to Proficiency test; the laboratory should participate in at least one inter laboratory proficiency testing (PT) program, sometimes referred to as a “round robin” testing program. Permanent sample exchange or inter laboratory programs. There should also be an SOP that defines how the participation in an inter laboratory proficiency testing program is conducted and administered (ASTM 2023).
Reproducibility data from such programs which may indicate whether the laboratory produces accurate (unbiased) results should also be maintained in a permanent file and summarized in statistical form or on control charts or both. Examine data for evidence of any persistent deviations from proficiency test averages that could indicate a bias. Breathing a sigh of relief that the laboratory’s results are within some arbitrary range of the proficiency test mean value on a month-to-month basis is not a satisfactory use of proficiency test data (Nadkarni 2000).
Written policies should define the statistically based level of nonconformance at which action needs to be taken to modify or recalibrate a procedure based on performance in the proficiency test program. Records of such actions should be documented. Responsibilities should be explicitly defined (ASTM 2002).
Concerning of control samples; internal control samples should be tested on a routine basis. A control sample might also be a RM, a sample that has a known composition traceable to a RM, a customer sample analyzed in replicate, or a fresh proficiency test sample. Control samples should be stable materials of appropriate top size with an appropriate matrix. Retesting a sample analyzed the previous day or shift is also recommended (ASTM 2000).
The procedures for using a control sample should also be specified in an SOP. Data from control samples should also be preserved in a permanent log or file and summarized in statistical or control chart form. Data from replicate analyses of control samples (or customer samples) are used to define precision (repeatability) performance, and these measures should be routinely updated and readily available.
Written policies should also be defined statistically significant nonconformance levels requiring action to be taken to investigate the accuracy of a procedure. Responsibility for reviewing control sample results should be explicitly specified, as should responsibility for taking appropriate corrective actions. Records of such actions should be documented (Nadkarni 2000).
There should be a written policy that defines how long data should be retained. This policy should cover 1) Calibration and control data and 2) Routine test data. Generally, one year is considered adequate for routine test data, longer for calibration and control data (ASTM 2023).
As far as calculations is concerned; for ease of reference and to facilitate auditing, a single document that shows all calculation procedures used for all tests should be included in the QA Manual. There should be a process to ensure that the procedures are rigidly followed. If calculations are performed on a computer, a printout should be results of a test program to demonstrate that the calculations are programmed correctly. Unless equipment sends data directly to a computer, there should be a specific worksheet used to record data for each test procedure. Some procedure should be used to ensure accurate data input to the worksheet or computer (Nadkarni 2000).
Regarding to data review, validation, and retesting all final data should be reviewed and validated before being transmitted to the customer. Often, the validity of data can be checked by assessing whether different parameters are consistent with each other.
For instance, laboratories that analyze coal from one source can check whether specific energy (calorific value) calculated to a dry, ash-free basis is consistent with an average from earlier analyses. Determined specific energy should agree with SE calculated from elemental analyses. Here should also be one individual responsible for this validation activity, and that individual should also have the authority, if incorrect data are suspected, to institute retesting or to check calibrations (ASTM 2023).
2.1.9. Fuel Quality Test Kits
For the case of gasoline the kits include the following tests such as 1) Gas Quality Test Swabs – quickly test fuel quality and level of decay of 2 and 4 cycle gasoline that contains ethanol and determine if the fuel is fresh, stale, or bad; 2) 2 Cycle Oil Indicator Test – indicates the amount of oil present in a 2 cycle gas / oil mixture 3) Diesel Fuel Quality Test – determines the quality of diesel fuel 4) 2 and 4 Cycle Gas Test – determines the quality of non-ethanol fuel (Highly Sensitive Test); 5) Phase Separation Test – detects phase separated ethanol blended gasoline and provides immediate results to show your customer; 6) Oil Quality Test – illustrates why customers should change their oil more frequently; and 7) Bound Water Test – Indicates the amount of water present prior to phase separation (Dhuha and Dawood 2012).
For the case of diesel the kits include the following components such as 1) case with Safety Foam Insert; 2) Diesel Hydrometer / API Specification; 3) Charts For Temp Correction; 4) results Chart, 5) DEF Refractometer; 6) Diesel Test Fluid with Dropper Bottle; 7) Liquid Transfer Dropper; 8) Fuel Sample Cylinder (50mL); and 9) Diesel fuel training course ($100 value (Sarıkoç 2022).
2.1.10. Analytical Methods on Controlling Fuel Adulteration
To detect gasoline so far literatures aired the following analytical approach, parameters/method, and test method. As analytical approach; these literatures consider physico-chemical properties. Some of the physico-chemical properties like density, RON, volatility, vapor pressure or MON can be used for detecting added solvents in gasoline, providing a primary evidence of its adulteration.
As parameters/method so far used were density, distillation, motor octane number (MON), research octane number (RON), antiknock index (AI), vapor pressure (VP), and kinematic viscosity (KV).
For instance, the octane number can be a very useful parameter to infer gasoline quality. Linear and longer hydrocarbon chains produce easily knockable compounds whilst aromatic species will tend to be knock resistant. Therefore, by determining gasoline octane number, it is possible to analyze it’s resistance to knocking, which, indirectly gives a lead on the gasoline chemical composition.
Specific to density ASTM D4052 was used as of test method (Takeshita, et al. 2008). Another adulterant that also proved to be easily detected was diesel. In this case, with only a 2% addition in volume, the flash point increases considerably. Regarding density results, the addition of dense compounds, like alkybenzene, can result in higher density values.
In terms of distillation ASTM D89 has been used as of test method (Mendes and Barbeira 2013). Even small solvent contents in the samples reflected considerable changes in the distillation curves, more particularly at higher vaporized percentage.
Thus, small changes in the gasoline samples were enough to set the final boiling point above specification limits. In fact, the use of distillation curves has been proved to be an efficient method, to identify gasoline adulterants (De Oliveira, et al. 2004.).
The ethanol is very easily detected trough distillation curves, where a sudden change in temperature, characteristic of an azeotropic mixture formed by ethanol and hydrocarbons is observed; hence a visual inspection is sufficient to confirm the presence of ethanol.
Specific to motor octane number ASTM D2700 was used as of test method (Teixeira, et al. 2001). Actually, the octane number is normally measured according to three different values: the motor octane number (MON), the research octane number (RON) and the mean between these two indices ((RON+MON)/2), indicating the anti-knocking quality of the given sample. For some time, determining RON and MON values, was the main focus when analyzing the quality of a gasoline samples, they were easy and quick measurements, obtained with portable analyzers.
According to Teixeira, et al. (2001) linked to research octane number (RON) and Antiknock Index (AI); ASTM D2699 was used so far. In terms of vapor pressure ASTMD5191 has been used as of test method (Mendes and Barbeira 2013). Specific to Kinematic viscosity; ASTM D445 was used as of test method (Teixeira, et al. 2001).
In addition, as analytical approach chromatography has also been used by considering High-performance liquid chromatography (HPLC), Chromatography (GC), Two-Dimensional Gas Chromatography (GCxGC), Gas chromatography mass spectrometry (GC-MS) as of parameters/methods. When it comes to chromatographic methods, it is possible to use High-Performance Liquid Chromatography (HPLC) to obtain a preliminary analysis of samples.
By using spectroscopy as analytical approach infrared, NMR, and Raman were used as of parameters/methods (Skrobot, et al. 2007). For spectroscopic methods InfraRed (IR) Spectroscopy, both in the mid (MIR) and near IR (NIR) spectral region is one of the most studied analyses (Gallignani, Garrigues and De la Guardia 1993).
For the case of diesel; The GC analysis comprised the n-paraffin distribution in the samples and carried out as per the standard test methods UOP915 and ASTM D6730 through a model CP3800 gas chromatograph equipped with flame ionization (Vempatapu, et al. 2019).
Others have also used the equipment a Quimis Q798FIL LED fluorescence spectrometer with a quartz cuvette of 1 cm path length as well as one violet light‑emitting diode (LED) centered at 400 nm as the excitation source. The emission range was 350-700 nm at intervals of 0.38 nm. The average values of triplicate spectral data were calculated, which were then integrated using Origin Pro8 software.
To assess the applicability of the fluorescence method in quantifying the adulterant content, an analytical curve was constructed using the concentrations of each adulterant in diesel and the relative change in fluorescence area of each blend with respect to the fluorescence area of the diesel (δ parameter) (Meira, et al. 2015).
This relative change (δ), as a percentage, is calculated as δ = [(A0 – Ai) / A0] × 100, where A0 and Ai are the integrated fluorescence areas of the diesel and adulterated diesel, respectively.
Recently, other studies have also used the method that is a portable apparatus that can be directly fitted in vehicles and adulteration can be checked on the go. The method employed uses polarimetry as the basis for sensing adulteration.
Polarimetry is utilized for the estimation and elucidation of energized transverse, most prominently electromagnetic waves, for example, radio or light waves. Normally, polarimetry is done on electromagnetic waves that have gone through or have been reflected, refracted, or diffracted by some material so as to describe that object (Gauci and Arkoudeas 2020).
An example is set in a basic polarimeter for estimation of revolution comprises of a long cylinder with glass put at each end. At each finish of the cylinder is a Nicol crystal or other polarizer. Light is shone through the cylinder, and the crystal at the opposite end, appended to an eye-piece, is turned to touch base at the locale of finish brilliance or that of half-dim, half-splendid or that of finish haziness. The edge of pivot is then perused from a scale (De Almeida e Silva 2020).
A similar marvel is seen after an edge of 180°. The explicit revolution of the example may then be determined. Temperature can influence the pivot of light, which ought to be represented in the estimations (De Almeida e Silva 2020). Fuels are tested using the portable Authentix Fuel Analyzer LQX 1000.
2.1.11. Fourier transform infrared spectroscopy (FTIR)
Fourier transform infrared spectroscopy (FTIR) is a largely used technique to identify the functional groups in the materials (gas, liquid, and solid) by using the beam of infrared radiations. The interaction of matter with any part of the electromagnetic spectrum is called spectroscopy, which is an instrumentally assisted study between matter and electromagnetic radiation of any range (Khan, Khan and Asiri 2018).
Electromagnetic spectrum is composed of various radiations containing different wavelengths, which is a type of radiant energy, ranging from gamma rays to X-rays via visible light to radio waves, each of which can be considered as a wave or particle traveling at the speed of light (Wu , Li and Tu; 2015). IR spectroscopy is an advanced and extensively used analytical tool that investigates the structural chemistry of the sample by irradiating with IR radiations. One of main advantages of FTIR spectroscopy is its capability to identify functional groups such as C=O, C-H, or N-H. FTIR spectroscopy enables by measuring all types of samples: solids, liquids, and gases (Erwanto, et al. 2016).
2.1.12. Mitigation strategy to halt fuel adulteration
To mitigate fuel adulteration UNDP / World Bank (2005) suggested the following issues in reference to institutional level, the customs organization more specifically, and some technical issues.
To the institution UNDP / World Bank (2005) suggested the following mitigation measures i.e.; 1) local authorities’ commitment, 2) adjust the tax structure to level the retail price of various oil products, 3) strengthen the role and resources of the regulatory agency, 4) recruit experts and train public servants on the oil industry and product, 5) improvement in cooperation and coordination, 6) communicate to the public to enhance awareness of oil product quality, and 7) ensure proper law enforcement.
To custom organization UNDP / World Bank (2005) recommended that 1) rreview and adapt the role of the customs services, 2) build and strengthen the capacities of customs services, and 3) post a customs officer or team at the refinery.
In addition, UNDP / World Bank (2005) suggested technical issues such as 1) sset up a test laboratory, 2) put dyes and tracers in “risky” products (industrial diesel and regular gasoline), 3) improve recordkeeping, and 4) adapt glass bends on dispensers.
The adjustment in octane rating may enact an issue called motor thumping. Avoiding fuel taxes reduces government revenue.
2.1.13. Theorizing the consequence of fuel adulteration and how to halt it
In this study the following most influential competing theories i.e.; Medieval theory; consequentialist theory; Utilitarianism; and consequentialist ethical theories are reviewed to better understand about the consequence of fuel adulteration.
In addition, following most theoretical concepts i.e.; criticisms such as different problematic aspects of consequentialist arguments, insufficiently backing the prediction of future consequences, the extension of the consequences to be considered, proof of the causal relation between an act and its foreseen consequences are reviewed to better understand about the consequence of fuel adulteration.
In the following most influential competing theoretical concepts such as unintentional events; reason explanations; reasoning process; subjectivity and rationality; person–situation dichotomy; unintentional human behaviors; control potential, emotion; and relational appraisal are reviewed to better understand about how to halt fuel adulteration.
The very term consequentia was in use in exactly this sense since Boethius (5th-6th Century): the topic itself occupied a prominent position in earlier traditions. Consequence is a conditional sentence. It is a logical relation between contents. Consequence is also an inference, i.e. the act performed by somebody of drawing a conclusion from premises (Carbonell 2011).
Others consider it as of the division into good and bad, or valid and invalid. According to Kesler (1623) a valid consequence, is a statement in which one proposition is inferred from another by a legitimate deduction, in such a way that the consequent is dependent on the antecedent (Ashworth 1973).
In medieval theories authors accept as a necessary condition for the validity of a consequence the incompatibility (modal) criterion: Medieval logicians sought not only to establish the validity of such basic rules; they also made inquiries on the very nature of logical consequence and inference (Ashworth 1973).
It is impossible for the antecedent to be true while the consequent is false. This was also a theoretical stand to the contemporary studies. For instance, in case of fuel adulteration the antecedent should be fuel adulteration; the consequence should also be the problems linked to fuel adulteration. In this sense, their investigations overlap not only with modern ‘proof theory’, but also with modern philosophy of logic (Carbonell 2011).
Next, the researcher reviewed literatures about consequentialist theory. To the consequentialist the moral value of an act is determined by the level of benefit toward the greater good that comes about as a result of an action. In treatise of Aylor (2015) Schafer-Landau (2013) considered consequentialism in the form of act consequentialism and rule consequentialism.
Most ethicists agree that while act consequentialism is good for use in momentary decision-making when there is no rule to refer too, its facets are way too general to be counted as an overall principle of morality. This is because act consequentialism requires that the moral decision-maker go from situation to situation to determine what constitutes the most benefit towards good with no guidelines for choosing this decision except that would be the action that generates the outcome with the most benefit to society. This was also a theoretical stand to the contemporary studies. For instance, this research as consequentialism; considers the action that generates the outcome with the most benefit to society.
In addition, this study has also reviewed literatures about Utilitarianism. In Tegegne’s article Schafer-Ladnau (2013) mentioned utilitarianism as a part of consequentialism. To a utilitarian, the greatest good is actually derived from the greatest amount of happiness. Therefore, each act either maximizes happiness or minimizes those things that generate unhappiness. For rule utilitarianism, “acts are right if and only if they are permitted by certain rules, namely those that would maximize the overall amount of happiness were they generally adhered to. This was also a theoretical stand to the contemporary studies. For instance, activities for halting fuel adulteration are acts right to maximize the overall amount of happiness were they generally adhered to.
However, the consequentialist theory is not also exempted from criticisms, The criticisms refer to different problematic aspects of consequentialist arguments, such insufficiently backing the prediction of future consequences, the extension of the consequences to be considered, proof of the causal relation between an act and its foreseen consequences, the parameters to evaluate or assess consequences against other values, interest or goods, and the question for what or for that are the consequences favorable or unfavorable, among others. This was also a theoretical stand to the contemporary studies. For instance, fuel adulteration is not exempted from criticisms. The amount of adulterants causing adulteration depends on the type of adulterants.
Further the researcher read about theoretical literatures about how we can halt fuel adulteration. Let us see in detail about consequentialist ethical theories. Consequentialist ethical theories maintain that right and wrong are a function of the consequences of our actions – more precisely, that our actions are right or wrong because, and only because, of their consequences. This was also a theoretical stand to the contemporary studies. For instance, fuel adulteration is wrong because of its consequence.
Actually, all ethical theories take consequences into account when assessing actions and almost all philosophers believe that the consequences of our actions at least sometimes affect their rightness or wrongness. What distinguishes consequentialist from non-consequentialist ethical theories is the insistence that when it comes to rightness or wrongness, nothing matters but the results of our actions. (Shaw 1993).
Let us discuss about a theory of mitigation. Mitigation is a cognitive but also a linguistic and a social phenomenon. It is applied to describe both expressions of politeness and reactions to stressors, such as blame.
Linked to mitigation this study has discussed about different theoretical approaches. Among these let us detail in about Attribution theory (Martinovski, et al. 2005). Attribution theory has explored people’s assessments of the accountability of social behavior for decades. The attribution approach focuses on the descriptive features of behavior explanation by identifying the broad features people use in determining cause, responsibility and blameworthiness (UNDP / World Bank 2005).
In this regard, the model of Shaver (1985) is the most influential. The judgment process underlying their models relies on several conceptual variables. For instance, in Shaver’s model first one assesses causality, distinguishing between personal causality (i.e., human agency) versus impersonal causality (i.e., situational factor) (Martinovski, et al. 2005).
If human agency is involved, the judgment proceeds by assessing whether the actor possessed the foreknowledge about the action and its consequence; whether the actor intended to produce the action consequence; whether the actor had choices or acted under coercion? (UNDP / World Bank 2005)
Causality and coercion determine who is responsible for the outcome, while intention and foreknowledge determine the degree of responsibility assigned. This was a theoretical stand to the contemporary studies. For instance, Causality and coercion determine who is responsible for the fuel adulteration consequence, while intention and foreknowledge determine the degree of responsibility assigned to halt fuel adulteration.
Further, Heider proposed that a process of attribution is involved in person perception as well, but he recognized that person perception is more complex than object perception – due to the manifold observational data available and the various causes (e.g., beliefs, desires, emotions, traits) to which these data can be attributed (Schmitt 2015).
Heider emphasized two distinct features of person perception. The first is that in the social domain, variance refers to the agent’s stream of ongoing behavior and invariance refers to the inferred perceptions, intentions, motives, traits, and sentiments. The second distinct feature of person perception is that when people perform a causal (i.e., attributional) analysis of human behavior, their judgments of causality follow one of two conceptual models (Malle 2011).
The first is a model of impersonal causality, applied to unintentional human behaviors (such as sneezing or feeling sad) and physical events (such as waves splashing or leaves falling). The second is a model of personal causality, which is invoked whenever a human agent performs an intentional action (such as cleaning the kitchen or inviting someone to dinner).
“Personal causality,” Heider wrote, “refers to instances in which p causes x intentionally. That is to say, the action is purposive”. This was a theoretical stand to the contemporary studies. For instance, human being carried out fuel adulteration for the purpose of making corpus of money by mixing exorbitant fuel with the fuel in less money value (UNDP / World Bank 2005).
In addition, Heider has been consistently credited with introducing the person–situation dichotomy in attribution theory. Heider’s actual theory was predicated on the distinction between personal causality (which accounts for intentional events) and impersonal causality (which accounts for unintentional events) – later recognized as a central element in social cognition (Schmitt 2015). This was also a theoretical stand to the contemporary studies. For instance, human being might carry out fuel adulteration intentionally (Schmitt 2015).
Let us see also about Modes of explanation to Unintentional events. Unintentional events are explained by referring to “mechanical” causal factors (e.g., physical objects and events, but also traits or others’ behaviors), and we may label them cause explanations. In contrast, explanations of intentional behavior are far more complex because the folk conception of intentional action is far more complex. As a result, explanations of intentional action break down into three modes reason explanations, causal history of reason explanations, and enabling factor explanations.
Reason explanations are the most frequently used mode, comprising about three-quarters of all action explanations. They link directly to the heart of the intentionality concept – the reasoning process leading up to an intention (Malle 2011).
The concept of intentionality specifies two paradigmatic types of reasons that precede the formation of an intention: the agent’s desire for an outcome and a belief that the intended action leads to that outcome. This was also a theoretical stand to the contemporary studies. For example, human being might carry out fuel adulteration because of his/her reason (Schmitt 2015).
On the other hand, reasons have two defining features: subjectivity and rationality. Subjectivity refers to the fact that reason explanations are designed to capture the agent’s subjective reasons for acting.
That is, social perceivers normally try to reconstruct the considerations the agent underwent when forming an intention, and they thus take the agent’s subjective viewpoint when explaining the action. This was also a theoretical stand to the contemporary studies. For example, ‘somebody make money’; in response to the question ‘Why did he/she carry out fuel adulteration? (Malle 2011).
Rationality, the second defining feature of reason explanations, refers to the fact that the contents of mental states that are cited as reasons have to hang together so as to offer support for the “reasonableness” of the intention and action they brought about (Schmitt 2015).
For an intentional action to be adequately explained by reasons, the action must fulfill the agent’s predominant desire in light of her beliefs. Philosophers often speak of a “practical reasoning argument,” in which reasons are the premises and the decision to act is its conclusion (Malle 2011).
Let us see Appraisal theory. In treatise of Martinovski, Gratch and Marsella (2005) Martinovski and Marsella, (2003) described mitigation in the light of coping. He has argued that the emotions are emerged from a person’s appraisal of the event (Rutgers and Smith 2014). This was also a theoretical stand to the contemporary studies. For instance, the emotions are emerged from a person’s appraisal of fuel adulteration consequence.
Further, the appraisal process makes it likely that emotions will be appropriate responses to the situations in which they occur. Several theorists maintain that the appraisal system has evolved to process information that predicts when particular emotional responses are likely to provide effective coping.
Note that to predict which emotional response would be adaptive; the appraisal system relates features of external situations to internal motives and resources. Functionally, control potential must be a relational appraisal, comparing the capabilities and resources of an individual with the requirements of a situation, in order to determine whether something can be done to make things better. This was also a theoretical stand to the contemporary studies. For instance, individuals need to compare their capabilities and resources in order to halt carrying out fuel adulteration.
2.2. Theoretical frame work
A theoretical framework of this thesis comprises the aforementioned issues expressed by theorists in the field into which this study plan to research, which the study draws upon to provide a theoretical coat hanger for its data analysis and interpretation of results. And the theoretical frame work is graphically presented below.
Figure 2.2: Theoretical frame work
Source: Own synthesis from literature review on UNDP / World Bank (2005), Malle (2011), Schmitt (2015), Rutgers and Smith (2014), Ashworth (1973), and Carbonell (2011)
2.3. Review of empirical studies
2.3.1. International studies
World Bank (2020) catched gasoline and diesel adulteration in Nigeria by conducting empirical study. The study revealed that adulteration of gasoline and diesel with lower-priced materials was common in South Asia as elsewhere in the world. It also aired that some adulterants increased emissions of harmfulpollutants from vehicles, worsening urban air pollution (World Bank 2020).
The study aslo recalled us the indirect adverse effect on society through the loss of tax revenue. It aslo described the impact of different types of adulteration on air quality and various methods for detection (World Bank 2020).
Nyabaro, Kituyi and Okemwa (2021) also assessed adulteration of gasoline (msp) and diesel (ago), in selected fuel stations in Kisii County. Purposeful sampling was carried out on investigating gasoline and diesel adulteration sold at selected fuel stations in a case study of Kisii County, and whether these products are within the standards set by Kenya bureau of Standards (KEBs) (Nyabaro, Kituyi and Okemwa 2021).
Samples of gasoline and diesel were collected from selected five fuel stations and two laboratory testing methods of ASTM D86 (Distillation) and ASTM D1298 (Density determination) were conducted at Vivo Energy Company laboratory in Nairobi (Nyabaro, Kituyi and Okemwa 2021). The result of analysis indicate that in this parameter three stations are out of the range for the samples and the remaining two are within the range specified by KEBS (2007) (Nyabaro, Kituyi and Okemwa 2021).
Gawande & Kaware (2013) conducted the study about fuel adulteration consequences in india. Tailpipe emissions from low level public transport such as auto rickshaw is a menace and become a serious problem due to their contribution in pollution and bypassing the subsidized kerosene to adulteration market. This study has developed techniques for fuel adulteration with kerosene. In addition, tailpipe emissions causing environmental impacts have been also studied.
In addition, Ofondu (2011) conducted the study about fuel adulteration and its consequences in reference to Nigeria. The study showed the rate of emission of CO (carbon II oxide) and PM (Particulate matters) from engines when they are run on adulterated fuel. Also the effects of adulteration on the environment and on human health were discussed and possible solutions to combat adulteration of fuel highlighted (Ofondu 2011).
Further, regarding to mitigation to fuel adulteration impact; UNDP / World Bank (2005) conducted the study about alleviating fuel adulteration practices in the downstream oil sector in Senegal. The study has carried out tentative quantitative and qualitative assessment of malpractice level and quality control mechanisms. The study revealed that the only efficient laboratory sufficiently equipped and with the proper human resources to check the quality of the fuel products in Senegal is the refinery’s laboratory (UNDP / World Bank 2005).
Moreover, Kwao-Boateng, et al. (2024) assessed diesel fuel quality. This study compared various fuel samples to understand the quality of the fuels in terms of sulphur content, density, surface tension, viscosity, and calorific value. The properties of diesel fuel samples from eight (8) Filling Stations (Marketing Companies (MC)) were examined and compared with GSA 141:2022 and ISO 8217:2017 standards. Fuel from two companies, MC-A and MC-G had slightly lower densities than the standard, indicative of a possible contamination with lower-density fuels such as kerosene. The surface tension of all samples, except one was within the standard range (Kwao-Boateng, et al. 2024).
The only sample with the lower than the standard value also displayed high sulphur content. Although all the fuel samples met the minimum requirement for calorific value, the viscosities of the fuels from three companies were slightly higher than the specified standard value which can potentially result in higher emissions (Kwao-Boateng, et al. 2024).
In the case of sulphur content, fuel samples from only three companies were in compliance with the maximum 50 ppm standard. This means 62.5 % of the diesel fuel within the study area at the time contained more than the acceptable amount of sulphur. The findings in this research highlight the need to re-examine the quality of fuels along the distribution chain (Kwao-Boateng, et al. 2024).
Meira, et al. (2015) also described a simple and rapid methodology for determining the content of adulterants in diesel by the integration of fluorescence spectra. The procedure consists of constructing analytical curves using the concentrations of each adulterant in diesel and the relative change in the fluorescence area of each blend with respect to the fluorescence area of the diesel (Meira, et al. 2015).
The results indicated that the proposed method can be used to determine adulterants such as non-transesterified residual cooking oil, kerosene, and turpentine in diesel. The detection limits were 3, 4 and 5% for non-transesterified residual cooking oil, kerosene and turpentine in diesel, respectively. The method was also successfully used to determine the non-transesterified residual cooking oil content in B5 biodiesel-diesel blend (5% biodiesel) in the range of 0-70%, with a limit of detection of 4% (Meira, et al. 2015).
Dadson, Pandam and Asiedu (2018) combined FTIR analyses with Chemometric (multivariate) techniques for qualitative and quantitative determination of four possible adulterants: kerosene, diesel, naphtha and premix in gasoline. Synthetic admixtures prepared by mixing the gasoline with varying proportions of the adulterants were obtained and used for the model calibration. Soft Independent Modeling Class Analogy (SIMCA) classification and Partial Least Square (PLS) regression methods were the Chemometric techniques employed (Dadson, Pandam and Asiedu 2018).
The SIMCA classification model developed predicted the type of adulterant present at an error rate of 6.25% for Kerosene and naphtha, and 12.5% for premix. However, no prediction error was recorded for classifying samples contaminated with diesel. The PLS regression model was able to predict the concentrations of adulterant with prediction errors lower than 5% for all adulterants (Dadson, Pandam and Asiedu 2018)
Mendes and Barbeira (2013) revealed a model with enough sensitivity to discriminate adulterated and unadulterated gasoline samples, as well as, the determination of the solvent used in adulteration with minimum percentage of 97% accuracy.
The scholars have used distillation curves combined with PCA (Principal Component Analysis) and PLS-DA (Partial Least Squares Discriminant Analysis). PLS-DA provided the prediction of adulterants with low RMSEC (Root Mean Square Error of Calibration) and low RMSEP (Root Mean Square Error of Prediction) when compared to other methods (Mendes and Barbeira 2013).
The great advantage is the possibility to apply the results of the distillation curves to routine analysis (ASTM D86), therefore not requiring various assays, speeding up the analytical process. In addition to its feasibility this method can be quite useful in fuel quality monitoring and inspection procedures whilst having low cost and good reliability (Mendes and Barbeira 2013).
2.3.2. Local studies
In case of Ethiopia Agnchew (2013) evaluated the quality control of gasoline against adultration in Addis Ababa city adminstration. The study desribed a quantitative study on adulteration problem in Addis Ababa and factors contributing to it. Two ways of sampling procedures were applied. 10 fuel stations’
MGR samples were taken to see the current status of adulteration via ASTM scientific method and 0.01% of the city’s salon vehicle drivers were sample size to study the problem of adulteration and its contributing factors (Agnchew 2013).
Sample taken as a surprise to see the status of the problem confirmed that 70% of the samples taken from ten petroleum stations of different companies are found to be adulterated. There are different factors contributing to adulteration of gasoline in the city.
The quantities of MGR and Kerosene supplied to the city’s market during the last three years, rate of supervision expressed as the frequency of supervision by regulatory body are contributing factors investigated by this research.
For the last three years, the quantity of importing both products was changing significantly, the rate of supervision by regulatory body is decreasing within the same period and gasoline adulteration has increased from 15% up to 50% of product being supplied to consumers (Agnchew 2013).
2.4. Synthesis of the Study
A conceptual model consists of various ideas that are entrenched in existing theories, sources and experiences mostly influenced by the context of the study (Parker , et al. 2022). To do this study; the researcher has decided to approach the study in comprehensive manner. Regarding to diesel adulteration these issues i.e.; 1) qualitative – is this gasoline adulterated; 2) Descriptive – What adulterant was added; 3) Quantitative – What level or % quantity does the adulterant represent of the total sample were considered. So far used analytical methods on controlling fuel adulteration were reviewed. For instance, to detect gasoline so far literatures aired the following analytical approach, parameters/method, and test method. In addition, consequences and mitigation strategies were also considered. So, a conceptual model of this thesis graphically presented below.
Figure 2.3: Conceptual model
Source: Own synthesis from empirical literature review on Dadson, Pandam and Asiedu (2018)
Gawande & Kaware (2013) and Agnchew (2013)