Chapter 1 INTRODUCTION

Transcription

1 Chapter 1 INTRODUCTION 1.1 Motivation With high economic growth rates and over 15% of the world s population, India is a significant consumer of energy resources. Despite the global financial crisis, India s energy demand continues to rise. In terms of end-use, energy demand in the transport sector is expected to be particularly high, as vehicle ownership, particularly of fourwheelers, is forecasted to increase rapidly in the years ahead. India lacks sufficient domestic energy resources and imports much of its growing energy requirements. In addition to pursuing domestic oil and gas exploration and production projects, India is also stepping up its natural gas imports. The demand for high speed diesel (HSD) is as high as 37% of the total petroleum consumption. In the wake of this, there is an urgent need to introduce alternate fuels as substitutes for HSD and Gasoline in the transport sector [1]. The sharp rise of conventional fossil fuel price is creating a huge effect on world economy. The issue of environmental pollution created by conventional fossil fuels is becoming more important. This concern as well as emission standards enforced by legislation, have led the research for the use of alternative fuels in different prime movers. The petroleum crude reserves however, are declining and consumption of transport fuels particularly in the developing countries is increasing at high rates. Severe shortage of liquid fuels derived from petroleum may be faced in the second half of this century. Energy security is an important consideration for development of future transport fuels. A number of liquid and gaseous fuels are among the potential fuel alternatives. Most important among them are alcohols, ethanol, methanol, natural gas, liquefied petroleum gas (LPG), hydrogen, gas to liquid (GTL) diesel, di-methyl ether (DME), biodiesel, straight vegetable oils, bio gas, etc., [2]. The major contributors in environmental pollution are automobiles. Internal Combustion engines (ICE) presently power almost all the road vehicles, and they are expected to remain as the principal prime movers. The vehicular pollution is increasing in multifold everyday, though efforts are being made to reduce it. The combustion generated

2 2 engine emissions have been at the centre of interest of researchers, automotive engineers, environmentalists and professionals for many years, they have proposed various remedies, one among them is to use of alternative energy fuels and it remains an active area of engineering research and education. Economic growth brings us many benefits and conveniences like jobs, wealth, etc. But it comes at a very high cost, too. Especially, air pollution caused by automobiles, has been described as disease of wealth [3]. Among the options that are currently available as alternate to Gasoline and Diesel, Compressed Natural Gas (CNG) has received a great deal of attention and has already been applied successfully to over a million vehicles in various parts of the world and is gaining increasing acceptance particularly for city transport vehicles taxi, buses, delivery trucks, garbage tippers, etc. The concept of natural gas as an automotive fuel started around Over two million natural gas vehicles (NGV) are in operation worldwide. Research has proved that it can be used safely. Many countries are using CNG as an automotive fuel. These include USA, Canada, UK, Italy, Thailand, Australia, Russia and New Zealand. In the eighties, other Asian & South American countries embarked upon CNG programmes namely, India, Bangladesh, Indonesia, Iran, Pakistan and Argentina. CNG has already made its way and LPG is gradually emerging as a potential alternate fuel. These are proven fuels in many countries and there are many numerous references on the technology of these fuels. In the last few decades CNG has received increased attention as a potential alternative fuel. CNG possesses superior combustion characteristics in terms of higher octane rating ( ), excellent knock resistance, lower rate of combustion pressure rise and low peak cylinder pressure and higher self ignition temperature (730º C). The Bhurelal Committee in 1998 recommended to the Supreme Court of India to use CNG in place of diesel for commercial vehicles operating in Delhi. By making this recommendation, they closed the option of using other technologies even on trial [4]. Once the alternate fuel is available to customers, infrastructure rather than technology is a key to market acceptance and growth of sales [5].

3 3 While Indian researchers have also worked on many alternatives to petroleum fuels and generated vast body of knowledge in technical literature, it is facing serious technological problems when it comes to implementation particularly working, storage, distribution and safety issues. 1.2 India Energy data for Oil and Gas According to Oil & Gas Journal (OGJ), India had approximately 5.6 billion barrels of proven oil reserves as of January India produced roughly 880 thousand barrels per day of total oil in 2009 from over 3,600 operating oil wells. In 2009, India consumed nearly 3 million barrels per day, making it the fourth largest consumer of oil in the world. Energy Information Administration (EIA) expects approximately 100 thousand barrels per day annual consumption growth through The combination of rising oil consumption and relatively flat production has left India increasingly dependent on imports to meet its petroleum demand. In 2009, India was the sixth largest net importer of oil in the world, importing nearly 2.1 million barrels per day or about 70% of its oil needs. The EIA expects India to become the fourth largest net importer of oil in the world by 2025, behind the United States, China, and Japan. Fig 1.1 shows India s oil production and consumption rate. Fig.1.1. India s Oil Production and Consumption rate [6]. According to OGJ, India had approximately 38 trillion cubic feet (tcf) of proven natural gas reserves as of January In 2009, India consumed roughly 1.8 tcf of natural gas, almost 300 billion cubic feet (bcf) more than in 2008, according to EIA estimates. Despite the steady increase in India s natural gas production, demand has

4 4 outstripped supply and the country has been a net importer of natural gas since India s net imports reached an estimated 445 bcf in Fig 1.2 shows India s dry natural gas production and consumption rate. Fig.1.2. India s Dry Natural Gas Production and Consumption [6]. Though the government has taken steps, in recent years, to deregulate the hydrocarbon industry and encourage greater foreign involvement, India s oil and gas sector is dominated by state-owned enterprises such as Oil and Natural Gas Corporation (ONGC), Oil India Limited (OIL), Indian Oil Corporation (IOC), Gas Authority of India Limited (GAIL), Gujarat State Petroleum Corporation (GSPC) and private Indian companies like Reliance Industries Limited, Essar Oil and Cairn India. 1.3 Significance The major factors leads to take this project in the context of current status for research are given below: 1. Increasing cost of petroleum products. 2. Uncertainty in the availability and affordability of petroleum fuels. 3. CNG and LPG fuelled engines offers a better solution to minimize pollution. The present CNG conversion technology requires modifications for better performance. This project will identify and give solution of the problem related with conversion technology, retrofitting new CNG engine in old vehicles and its performance.

5 5 4. As a commercial application, this research is very helpful to the state transport undertakings, automobile manufacturers and society at large. 1.4 Objectives The broad objectives of present study are given below: 1. To study the existing Compression Ignition (CI) and Spark Ignition (SI) engine structure for using conventional fuels and modifications in structure for suitability of alternative fuels. 2. To prepare analytical combustion model. 3. To study CNG and LPG as a fuel for automobile: a. Chemical composition and organic structure. b. Physical, chemical and combustion properties. 4. CNG and LPG kit Study of construction and working. 5. Modification in structure and different components of SI engine. 6. Modification in structure and different components of CI engine. 7. Analysis of performance characteristics of CNG, LPG and Gasoline fuelled engine. 8. To investigate the pollutant for CNG, LPG and Gasoline fuelled engine. 9. Case study Evaluation of retrofitted state transport bus for CNG Research Overview The primary goal of this research is to investigate the performance and emission characteristic of CNG and LPG fuelled engine. Gasoline and diesel engines are important source of particulate emissions. About 0.2 to 0.5% of fuel mass is emitted as small (~0.1 micrometer diameter) particles, which consist primarily of soot with some additional absorbed hydrocarbon material. Use of CNG and LPG could be a cost effective approach for reducing particulate emissions in engine compared to engine design and hardware changes. This research work has been carried out with an objective to study the role of CNG and LPG as a fuel to reduce emission & pollutants from Gasoline and Diesel engines.

6 6 The retrofitment of CNG/LPG kit has been studied and working of low pressure regulator (LPR) is verified for suitability of engine performance of maruti 800 MPFI engine. Combustion modeling has been done to study stoichiometry, heat of combustion and lean and rich limit of equivalence ratio for Gasoline, LPG and CNG fuels. The effect of spark advance has been studied on performance and emission characteristics for Gasoline, LPG and CNG. Cost analysis has been also done for all fuels in the context of current price of fuels. 1.5 Thesis Organization The remaining chapters in this thesis have been organized in following manner: Chapter 2 reviews the literature related to experimental investigation of performance of various fuels. The emphasis of the review is to identify the influence of various factors including stoichiometry, heat of combustion and spark advance on output power, fuel consumption and pollutants. Chapter 3 represents the study of conventional and alternative fuels, properties of various fuels, comparative analysis, emissions and air pollution aspects. Chapter 4 discusses the analytical work related to model chemistry and fuel mole fraction characterization in combustion model. An approach to optimize engine performance by combustion modeling is used for gaseous fuels. Model chemistry, heat of combustion of fuels, stoichiometry, flammability limits and spark advance module are analysed. A case study of state transport retrofitted bus is included in this chapter. Chapter 5 explains detailed analysis of CNG/LPG conversion kit, its requirement and functioning of each component. Details of working of low pressure regulator (LPR), and design of lever, cylindrical chamber and spring have been done. Mass flow rate of various stages have been calculated and discussed. Chapter 6 describes experimental work methodology and modification in the original set-up. Chapter 7 represents experimental results of Gasoline, LPG and CNG fuelled engine for various spark advances. The results on brake power, brake specific fuel consumption (bsfc), indicated power, brake thermal efficiency (η bth ), Air-Fuel ratio (A/F), volumetric efficiency (η v ), fuel mole fraction, oxygen mole, equivalence ratio (φ) and air

7 7 equivalence ratio (λ) have been compared and discussed. A comparative study of cost analysis and pollutants like carbon dioxide (CO 2 ), carbon monoxide (CO) and hydro carbon (HC) for all three fuels at various spark advances have been presented. Finally chapter 8 summarizes the major conclusions of the present study and recommends scope for future work.