CHAPTER 1 INTRODUCTION

Transcription

1 1 CHAPTER 1 INTRODUCTION 1.1 GENERAL With a rapid increase in the demand of fossil fuel, decrease in the availability of crude oil supplies and greater environmental stringent norms on pollution has created enormous interest in researchers in formulating and testing biofuels in recent times. The most promising method for deriving biodiesel from renewable energy source is transesterification process. Many vegetables plants were found successful in the production of biodiesel like Neem, Jatropha, Karanja, Cotton seed, Rapeseed, Soyabean, etc. It has also been reported in the literature that the use of biodiesel considerably reduced emission and increased the performance of engine (Agarwal et al. 2001, 2007). Many researchers have reported on the possibility for production of biodiesel from algae. Algal growth is photosynthetic in nature (i.e) they mainly use sunlight along with nutrients for their growth. Chlorophyll A and Chlorophyll B are the main components which undergo metabolic activities. Algae have a capability of fixing atmospheric carbon di-oxide and can be grown in intensive culture on a non-arable land. Demirbas (2011) has reporter that algae can be converted into biodiesel, Bioethanol, bio hydrogen, bio oil and bio methane through bio-chemical and thermo chemical methods. Chen et al. (2011) have reported on the growth and oil content in blue green algae. He has analyzed the growth factor of algae with a significant change in quantity of nutrients and noticed that under nitrogen deficit condition, the oil content (lipid) was increased in algae with respect to time.

2 2 In certain parts of India, Jatropha curcas plant commonly grown in hot climatic areas is one of the most promising source of biodiesel. Jatropha can be grown in waste lands and it can yield more than four times as much biodiesel per hectare as soyabean and ten times more than corn. But commercial cultivation of Jatropha raises several significant challenges in transesterification and cursin removal. Because of difficulties in procuring oil seeds and lack of infrastructure may obstruct the production of biodiesel. So far National Bioenergy Limited (NBL) and Southern biotechnologies India have embarked on biodiesel production from Jatropha curcas which has been set by National biodiesel mission developed by Government of India. Based on the above said limitations of Jatropha, an alternative feed stock for the generation of biodiesel is necessary. In the case microalgae is considered as the feed stock. Microalgae are a diverse group of prokaryotic and eukaryotic photosynthetic microorganism which grows rapidly due to their simple structure. Microalgae have been investigated for the production of biodiesel, bio-oil, bio-syngas and bio-hydrogen. It was estimated to be more than 2,00,000 species of microalgae which are capable of producing lipids. On-going advances in cultivation techniques coupled with genetic manipulation of crucial metabolic networks will further enhance microalgae as an attractive platform for the production of numerous high value compounds. Microalgae with lipid content upto 60% grown in saline or sea water have the potential to be the source of biodiesel. In India, algal biodiesel research is being pursued by few institute like Fisheries college and research Institute (FCRI), Tuticorin. Bharat Petroleum Corporation Limited (BPCL) has signed memorandum of Understanding with Tamil Nadu Agricultural University to develop technologies for alternative renewable energy using algaes.

3 3 Generally vegetable oil posses high viscosity. They must be reduced in order to improve the engine performance. There are several methods available to reduce the viscosity of vegetable oil like heating, pyrolysis, transesterification, thermal reduction and many more in which transesterification is the most suited and widely accepted method which involves chemical such as methanol, catalyst like sodium hydroxide and potassium hydroxide in the presence of heat energy. Agarwal et al. (2009) has studied the effect of karanja biodiesel on performance and emission characteristics in a single cylinder diesel engine in which he obtained better spray and atomization characteristics when biodiesel was preheated. Ganapathy et al. (2011) has also investigated the performance, combustion and emission parameters of a compression ignition engine using Jatropha biodiesel at variable injection timing. He advanced and retarded the injection timing by five degree from the rated value with constant injection pressure (200 bars) and found that on advanced injection timing, the performance, combustion and emission was better than the rated timing with a marginal increase in oxides of nitrogen. 1.2 OUTLINE OF THESIS More and more research studies are being carried out on the use of biodiesel on compression ignition engine. Algal oil seems to be very suitable oil yielding protocol in the near future when the fossil fuel get completely depleted on one side and increased demand on fuel for the transportation sector on the other side. In this research, blue green alga, Arthrospira maxima (Spirulina maxima) is used to yield algal oil. The lipid content of Spirulina Spp. was found to be 10% to 20% of its dry mass. The alga was allowed to grow in the laboratory condition and open pond culture. Upon harvesting, the algal oil was extracted through solvent extraction and expeller method. Cyclohexane

4 4 was added to expel remaining oil from the biomass and was purified. The algal oil was characterized by analyzing the physio-chemical properties. Transesterification process was carried out with methanol and sodium hydroxide which yields algal oil methyl ester and glycerol. The AOME was separated and purified. The AOME was standardized using several biochemical techniques includes Thin layer Chromatography, Gas Chromatography Mass Spectroscopy, Nuclear Magnetic Resonance spectral studies, Fourier Transform Infra Red analysis and elemental studies. The physical and chemical properties of AOME were determined and found to meet the standards. The suitability of AOME blends in compression ignition engine was carried out by using 5%, 10%, 15% and 20% blends of AOME with diesel in CI engine. The effect of AOME blends on In cylinder pressure, Peak pressure, heat release rate, combustion duration, combustion stability, brake specific energy consumption, brake thermal efficiency and emission were studied. Optimization of injection timing was also studied in the same engine. The test results were compared, analyzed and found that combustion, performance and emission data were satisfactory and are in acceptable level for the test engine. 1.3 ORGANIZATION OF THESIS Chapter 1 gives the basic outline and objective of the research. Chapter 2 deals with the literature survey, Chapter 3 gives details about various blue green algae, oleaginous algae, and characteristics of Chlorella Spp., Spirulina Spp., and Cyanobacteria Spp. This chapter also deals with morphological study, composition and properties of Spirulina Spp. Chapter 4 discusses the growth and harvesting of algal biomass. The biodiesel formulation, transesterification and properties of Algal oil methyl ester are also dealt. Chapter 5 gives the details about combustion study. Chapter 6 deals with experimental setup used for investigating the AOME blends.

5 5 Chapter 7 discusses the results on combustion, performance and emission parameters with variation in injection timing. Chapter 8 highlights the conclusion and future scope. 1.4 OBJECTIVE AND METHODOLOGY The objective of the present research is to Identify suitable blue green algae for the production of biodiesel in Indian condition. Suggest a suitable culture medium and supplements for algal growth. Optimize the transesterification efficiency. Standardize the algal oil through Thin Layer Chromatography, Gas chromatography, Mass Spectroscopy, Nuclear Magnetic Resonance (Carbon and Proton), Fourier Transform Infra Red analysis and Elemental analysis. Evaluate the benefits and limitations of algal oil methyl ester blends on combustion, performance and emission through experiments. Perform combustion, performance and emission testing of AOME diesel blends. Suggest a suitable blending ratio of AOME and diesel blends based on combustion, performance and emission studies. Optimize the injection timing when using AOME blends to obtain better results.

6 6 The methodology adopted is outlined below The initial screening of various blue green algae was done by studying their oleaginous properties, physical appearance, toxicity, growth characteristics, adaptability and environmental condition after an extensive literature survey. The selection of blue green algae was narrowed down to three oleaginous algae namely Chlorella Spp., Spirulina Spp., and Cyanobacteria Spp., based on the above factors. All the three algae were allowed to grow on a trial basis at different environmental condition and were successful with Spirulina Spp. The mass culture was processed with Spirulina Spp. and the algal oil was extracted followed by transesterification process. The physio-chemical properties of the algal oil and its blend were evaluated. The AOME was standardized using several biochemical techniques includes TLC, GC/MS, NMR, FT IR and elemental analysis. Experiments were than conducted to evaluate the effect of AOME blends on combustion, performance and emission. An optimization study by varying the injection timing was also carried out. Finally the experiment results were validated by comparing with value obtained for diesel from standard technical papers.