PhD Theses (Energy Science and Engineering)

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    Investigation on Usability of Porous Media in Kerosene Pressure Stoves for Improvement of Thermal Performance
    (2010) Sharma, Monikankana
    In developing countries, kerosene is considered as one of the principal cooking fuels and it is normally burnt in two kinds of stoves: wick type and pressure type. The pressure type stoves perform reasonably well; however the growing awareness about conservation of energy and reduction of pollution has necessitated their further improvements. Towards the above goal, in this study, a conventional kerosene pressure stove was modified to incorporate a bi-layered porous media consisting of alumina (Al2O3) and silicon carbide (SiC) enclosed in 6 different types of casing in the combustion zone. The thermal performance of the stove was evaluated with each type of casing. The main aspects of the thermal performance include temperature, emission and efficiency measurements. The emission and efficiency studies were conducted for different fuel and air flow rates. It was observed that the burner could be operated in a much leaner condition without affecting the stability of the flame. CO and NOx were measured at different air fuel ratios. The lowest CO emission (30 ppm) was observed for the fuel flow rate: 220 g/hr and air flow rate 120 lpm. CO emission was found sensitive to heat input and air flow rate. While, NOx behaviour was found insensitive to both heat input and air flow rate. The lowest NOx recorded was 1.2 ppm. The temperature measurements were taken at different radial and axial locations. The average surface temperature was found ~800 oC and it was found to increase with increase in air and fuel flow rates. The efficiency test of the burner was conducted as per the standard water boiling test (WBT) in accordance with the BIS standard: IS 10109: 2002. The highest efficiency (~57%) was recorded for the fuel flow rate: 160 g/hr and air flow rate rate: 150 lpm and this was obtained for a conical casing. Further, the efficiency also varied with vessel sizes and the different spacings between the vessel and the burner.The optimum distances giving the best thermal performance have been identified. An analysis has been carried out to calculate the efficiencies of the burner,working in different operating conditions, from the second law point of view. It was found that with increase in air flow rate the energy efficiency or the first law efficiency increases, while the exergy efficiency decreases. Similarly, the exergy efficiency increases with increase in fuel flow rate which is reverse in case of the first the efficiency. Thus, considering both first law and second law efficiencies, the air flow rate 120-130 lpm was found optimum. The conical casing shows the highest second law efficiency too. Finally, the thermal performances of the stove with new burner were compared with a conventional BIS specified stove. For the same heat input, the conventional stove showed higher CO (80-90 ppm) and NOx (3-4 ppm) but first (thermal efficiency) and second law efficiencies (exergy efficiency) were comparable.....
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    Clean Development Mechanism Potential of Compression Ignition Diesel Engines Using Gaseous Fuels in Dual Fuel Mode
    (2011) Sahoo, Bibhuti Bhusan
    The climate change problem results from the concentration of greenhouse gases (GHGs) in the atmosphere. The purpose of the Clean Development Mechanism (CDM) is to promote clean development in developing countries, and is based on the idea of emission reduction DproductionD. These reductions are DproducedD and then subtracted against a hypothetical DbaselineD of emissions. The fossil gasoline and diesel petroleum fuels used in internal combustion (IC) engines are one of the contributors to the global environmental degradation for their GHG emissions. Diesel engines contribute on important part of the worldDs transportation and industrial infrastructure, especially in heavy-duty equipment such as trucks, buses, construction and farm equipments, locomotives, ships etc. In the recent times, there are issues related to their GHG emissions such as, carbon dioxide (CO2), methane (CH4), and carbon monoxide (CO). The use of alternative fuels is one of the most effective means of resolving this problem. Gaseous fuels receive more prominence in the domain of alternative fuels because of the possibilities of cleaner combustion. However, they are not suitable for compression ignition (CI) concept diesel engine when used alone due to their low cetane numbers and high auto-ignition temperatures. Hence, the CI engine of the Ddual fuelD approach plays a significant role in the efficient utilization of a wide range of gaseous fuels. During a dual fuel operation, a carbureted air-gas mixture is sucked and compressed like in a conventional diesel engine. The compressed air-gas mixture is fired by a small liquid fuel injection, pilot, which ignites spontaneously at the end of compression process. Biogas and syngas are the two alternative gaseous fuels examined in the present investigation. In general, Biogas is produced by Danaerobic digestionD process where the timing, pilot fuel mass inducted, intake manifold conditions, and type of gaseous fuel, have effects on the performance, combustion and emission characteristics of dual fuel diesel engines. However, the systematic investigations of individual parameters relevant to engine characterization have not been reported exhaustively in the literature. The second law analysis or evaluation of available energy determines the maximum possible performance of a thermodynamic system. In addition, impact of process change in the system in terms of system losses is also assessed. These findings help in reducing the availability loss to improve the performance of the engine in terms of efficiency and power output. However, there were only few literatures accessed on availability analysis of dual fuel engines. Therefore, the present contribution is focused to perform a systematic experimental investigation including the thermodynamic behavior of diesel engine under dual fuel mode. To accomplish the above problems of diesel engines, few additional components such as gas mixer and gas carburetor were designed, developed and incorporated into the base engine setup for executing the dual fuel operation. Experiments were conducted on a modified engine test unit so as to run biogas and syngas under dual fuel operations. The base diesel engine is a single-cylinder, constant-speed, water-cooled and direct-ignition diesel engine with a rated power of 5.2 kW at 1500 rpm.....
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    Thermodynamic Optimization of Biomass Gasification
    (2011) Buragohain, Buljit
    For a developing country like India, meeting energy needs (mainly in the form of electricity and transportation fuels) in various sectors such as agriculture, industrial and transport is vital to achieve sustainable growth and economic development. The electricity generation in India is dominated by coal-thermal route [1]. Although the total installed capacity for electricity generation is 148 GW (as on February 2009), it is far insufficient to meet the needs of the population [2]. Moreover, supply of electricity to remote regions and hilly terrains (especially in the northeastern states) is difficult as extension of grid to these places is impractical. The transmission losses are as high as 30% and fluctuations in voltage are beyond acceptable limits [1,2]. Therefore, there is an urgent need to utilize and promote renewable energy sources in order to make these regions independent from grid supply [3]. Various options for decentralized electricity generation through renewable sources include biomass gasification, solar, wind and small hydro. However, from Indian perspective biomass gasification is the most feasible option among these for various reasons [4-9]: (1) biomass is
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    Butanol Production from Rice Straw : Process Development and Optimization
    (2012) Ranjan, Amrita
    Abstract not found
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    Development and performance evaluation of a natural convection grain dryer .2012.
    (2012) Mohapatra, Siba Shankar
    Abstract not found
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    Germplasm Evaluation, Environmental Impact Assessment and Genetic Improvement Studies in Jatropha curcas
    (2012) Mazumdar, Purabi
    The utilization of plant biofuel based Jatropha curcas feedstock is emerging as promising solution to problems of depletion of fossil fuel, fuel crisis and concern over global climate change. Large scale profitable cultivation of Jatropha is still in its infancy due to low and inconsistent yield and slow progress in identification of elite germplasm. Identification of elite germplasm from diverse agro-climatic region vis-a-vis development of superior genotype for higher seed yield and oil content, earlier maturity, reduced plant height, resistance to pests and diseases, drought resistance/tolerance, higher ratio of female to male flowers and improved fuel properties is expected to enhance the utility of Jatropha seed feedstock for biofuel. Adaptation of Jatropha to a wide range of climatic conditions including Northeast India, one of the biodiversity hot spot of the world, suggests existence of considerable genetic variation in growth and seed oil traits which can be potentially harnessed for selection of elite germplasm having high oil content and yield. Systematic analysis of the seed oil content and physicochemical properties forms the basis for identification of elite lines of J. curcas for commercial biodiesel production program. Life cycle assessment of Jatropha based biodiesel production can indicate its environmental impact and this analysis can also assist in adapting to appropriate biodiesel feedstock with minimum impact on environment. Lack of disease and stress tolerant accessions of Jatropha prohibits its successful commercial plantation program. Introduction and expresssion of crystalline toxin genes (cry) derived from Bacillus thuringiensis (Bt) through transgenic approaches have proven as effective mechanisms for protecting crops against insect infestations. In Jatropha, absence of an efficient and reproducible in vitro regeneration system amenable to gene transfer through Agrobacterium-mediated transformation hinders its genetic improvement program. In the present study, elite accessions of J. curcas from Assam, a state in North East India were identified on the basis of their seed trait and oil content. The oil content of the four elite accessions was found in the range of 37.6-46.6%. Analysis of physico-chemical properties of the oil and biodiesel obtained from seeds of these elite accessions demonstrated that they were within acceptable range of standards specifications of ASTM D6751. Life cycle assessment of Jatropha biodiesel production indicated its cultivation process generating highest environmental impact as compared to other stages of its life cycle, and showed higher sustainability of biodiesel from Jatropha as compared to Pongamia. An efficient and reproducible de novo plant regeneration system from cotyledonary leaf segment explants amenable to genetic manipulation through Agrobacterium-mediated transformation was established. The choice of explants of appropriate age and the orientation of the explants in culture medium were found to exert significant influence on the frequency of de novo plant regeneration. Furthermore, the age of the explant was found to be the critical aspect in conferring appropriate biological condition of the explant vital for optimal infection and T-DNA transfer by Agrobacterium tumefaciens. Highest regeneration response was reported.
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    Studies on immobilized lipase and biosurfactant for hydrolysis and transesterification of sunflower oil
    (2012) Chatterjee, Sushovan
    The principal objective of this work is immobilization of lipase and application of the immobilized lipase for hydrolysis and transesterification of sunflower oil. Lipase was isolated from the culture supernatant of Pseudomonas aeruginosa PG01. A high activity (4.1+- 0.05 U/ml) in the supernatant was detected when sunflower oil (2g/l) was used as the sole substrate. A significant production of lipase in burnt oil was observed, which was about 75% of the activity obtained when sunflower oil was used as the substrate. The extracellular lipase was successfully fractionated from the culture supernatant by ammonium- sulfate fractionating method, which was further purified by DEAS- sepharose anion exchange chromatography. The specific activity of the purified lipase was increased to 2.59 fold. The molecular weight of the DEAS sepharose filtered purified pseudomonas lipase was estimated by SDS-PAGE was found to be 55 kDa. The optimum temperature and pH of the isolated lipase was 30oC and 7, respectively. The t1/2 of the lipase at 4C and pH 7 was nearly 23 months. The stability of the powdered lipase diminished steadily with the increasing temperature from 20o C to 80o C with t1/2 of 62 days and 82 min at 20o C and 80o C respectively.
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    Investigation of Hydrodynamics and heat Transfer Characteristics with Biomass Blends in a Pressurized Circulating Fluidized Bed
    (2013) Kalita, Pankaj
    Pressurized circulating fluidized bed (PCFB) is gaining popularity among the scientific community in utilizing low grade fuel for the combustion and gasification applications due to its in-built capability of capturing of sulphur and NOx. Compactness, high heat release rate and less amount of sorbent requirement makes the PCFB system more attractive. However, the complexity in hydrodynamics and heat transfer phenomena associated with bed geometry, flow parameters as well as type of fuels etc., demands for extensive research so as to open an avenue for designing of a PCFB system. In the present investigation, two PCFB units (one cold bed and the other being hot bed) of similar dimensions have been designed and fabricated in order to investigate the hydrodynamics and heat transfer characteristics experimentally. The bed hydrodynamics along the height of the riser was investigated in the cold bed unit. The effect of superficial velocity, solid inventory, particle size and operating pressures were investigated on bed voidage and suspension density. A heat transfer probe was installed at the upper splash region of the riser to investigate the wall-to-bed heat transfer coefficient along the height of the probe. The radial variation of heat transfer coefficient was investigated at a height of 1.57 m from the distributor. The hydrodynamics and heat transfer characteristics for different blending ratios of sawdust with sand and different weight composition ratios were also investigated at different operating conditions. The hot PCFB unit has been developed to investigate the effect of temperature and pressure on bed-to-wall heat transfer and quality of product gas at different biomass blending ratios. Gas composition was evaluated with the help of a gas chromatography and a flue gas analyser. Two heat transfer probes were installed at the upper splash region of the riser to investigate the heat transfer coefficient. The heat transfer coefficient was calculated without and with twisted tapes at different solid inventories and the performance was compared. Results obtained in the present investigation were found to be well comparable with the published results. The blending of biomass used for the above investigation in the PCFB units has been characterized to understand the change of thermal property with the increase of rate of heating. To investigate the effect of heating rates on the degradation of biomass the experiments were performed at three different heating rates of 10, 30 and 80 ओC/min while performing thermogravimetric (TG) analysis. The degradation of mass with temperature was validated numerically. The kinetic parameters of biomass were evaluated for both first and second reaction zones. The thermal response of biomass undergoing decomposition has also been modelled by using one dimensional (1-D) transient thermal model. The model was tested by using transient conduction Heisler chart. This study is important to understand the requirement of optimum fluidizing air for a combustor and to maintain a temperature required for gasification when it operates below sub stoichiometric condition.
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    Morphometric, Molecular and Biochemical characterization of Jatropha germplasm of North-East India
    (2013) Basu, Adreeja
    Physic nut (Jatropha curcas L.) is emerging as a sustainable alternative source of bio-fuel for mitigation of global energy crisis. However, profitable exploitation of J. curcas through large scale production schemes is still in its infancy mainly due to unpredictable seed yield traits and seed toxicity. Furthermore, the plant suffers from narrow genetic base. Identification of promising populations of J. curcas from wild habitat or distinct agroclimatic regions is of foremost importance for overcoming this constraints and development of superior varieties in breeding programs. However, in spite of increasing global importance of J. curcas as a bioenergy crop, till date, very little comprehensive studies on estimation of morphological and biochemical characters of J. curcas along with assessment of genetic variation within the germplasm has been conducted for screening and identification of elite and genetically divergent planting materials. With an objective to identify promising J. curcas populations, twenty nine populations were collected systematically from distinct agro-climatic regions of North-East India. Four populations from other parts of India were also included in the study as outgroup. In the present investigation, the morphological variation of J. curcas populations were assessed using agronomically important morphometric traits like plant height, collar diameter, canopy spread, floral sex ratios and yield associated traits like 100 seed weight and total seed yield. Highly significant differences in phenotypic characters were observed among J. curcas populations. The highest broad-sense heritability (%) was recorded for M: F ratio (88.07) and the lowest for canopy spread (66.39). The morphometric characterization of J. curcas populations on the basis of cluster and principal component analyses depicted that association among populations is independent of geographical origin. Seven promising J. curcas populations (IITJC7, IITJC15, IITJC19, IITJC21, IITJC22, IITJC24 and IITJC28) identified from North-East India on the basis of morphological characterization can be used as potential starting material for J. curcas improvement ventures.
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    Synthesis of Green Transportation Fuel: Investigations in Ultrasonic Route to Biodiesel Production
    (2014) Choudhury, Hanif A.
    Abstract not available
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    Studies on Cultivation Strategies and Biodiesel Production from Selected Microalgae Species of North-East India
    (2015) Difusa, Amrita
    The thesis aims to select a potential microalgae species from existing ‘microalgae resources’ of the region and their potential aspects towards biodiesel production. Chloromonas species ADIITEC-III was isolated and identified as a new microalgae strain from the region. Scenedesmus sp (GUBIOTJT116) was taken as a reference species from the Department of Biotechnology, Gauhati University. Under the optimum physiological condition, total lipid yield of ADIITEC-III and GUBIOTJT116 was recorded to be 31.8 ± 0.9% and 35.2 ± 0.72% respectively. Nitrogen supplementation was studied to address the importance of nitrogen which plays an imperative role in microalgal lipids and fatty acid metabolism. Among the studied nitrogen sources, ammonium nitrate supports the lipid yield 35.86% in ADIITEC-III and GUBIOTJT116 showed high lipid yield (37.2%) with urea. Therefore, based on high lipid yield, the oil recovered from the isolates was transesterified into methyl esters (FAME) and was characterized by 1H NMR spectrophotometer, thermogravimetric analysis (TGA), FTIR spectroscopy, acid value, iodine value, bomb calorimeter and differential scanning calorimetric (DSC) analysis. Thereafter, the FTIR spectrum of the oil sample of both the strains obtained under different nitrogen sources were investigated in detailed using the chemometric techniques of discriminate analysis and multivariate calibrations. Both the strains were further subjected to salt (NaCl) stress to enhance the lipid yield. Based on the data obtained, ADIITEC-III was selected for two stage cultivation and showed high biomass productivity (1.5 ± 0.3 gL-1) and increased lipid content of up to 40.8 ± 0.2%. Moreover, ADIITEC-III under high salt stress condition (NaCl) showed better biodiesel properties than control condition. Further, the thesis includes the utilization of cow dung and piggery waste as an effective alternative media for microalgae biomass production. The cow dung and piggery waste were characterized for their elemental composition and based on the compositions a range of concentrations i.e. 5%, 10% and 15% were considered for the experimentation. Increased lipid yield was noticed at 5% cow dung and piggery waste concentrations for ADIITEC-III and GUBIOTJT116 compared to the culture grown in BG11 medium. The physicochemical characteristics of synthesized methyl esters (FAME) of ADIITEC-III and GUBIOTJT116 were evaluated and were found to be within the limits of ASTM D6751 biodiesel standards. Thus, ADIITECIII and GUBIOTJT116 could be a potential feedstock for biodiesel production.
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    Development of Nanocomposite Based Bioelectrodes using Alcohol Oxidase and Laccase as Biocatalysts for Bioelectronic Applications
    (2015) Das, Madhuri
    This study at fabricating alcohol oxidase( based bioelectrode for biosensors and biofuel cell application...
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    Overexpression of AtDGAT1 and metabolome analysis of Jatropha Curcas L. for enhanced oil in seeds and leaves
    (2016) Maravi, Devendra Kumar
    The diminishing fossil fuel stock and soaring international crude oil price have renewed the interest in the alternative source of fuels. Oil from oilseed crops that are largely in the form of triacylglycerol (TAG) are the promising source of renewable supply of fuels in the form of biodiesel. Jatropha curcas L is an important non-edible oilseed crop which received worldwide attention as a biodiesel feedstock. Despite the significance of Jatropha seed oil as a potential source of biodiesel, not much research efforts have been made through breeding or transgenic approaches to improve its seed oil quality for sustainable biodiesel production. Transgenic approaches offer immense opportunities to improve oil content and quality through manipulation of oil biosynthetic pathway in both seed and leaves.
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    Science-Policy Interface to Mitigate Water Scarcity in India : An Assessment of Virtual Water Flows
    (2016) Katyaini, Suparana
    Freshwater resources are essential for functioning of the economy, environment and society. From the perspective of sustainable development, the economy is considered as a subset of the environment. Therefore, freshwater resources act as both the source to, and the sink of the economy. Water security integrates the role of freshwater resources as a source as well as the sink of economy, through emphasis on ‘sustainable use’ of freshwater. Sustainable use of freshwater resources necessitates strengthening of science-policy interface to bridge the knowledge-governance gap in translating scientific knowledge into policy actions. Virtual water (VW), which is an indicator of freshwater embodied in goods and services, was developed to induce and enhance sustainable use of freshwater resources in water-scarce regions of the world. VW-flows concept is at the science-policy interface. This is because it is based on the rationales of ‘distribution of water scarcity’ among regions with different water endowments, enhancing ‘global water use efficiency’ and ‘net water savings’.
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    Profiling of selected grass species for bioethanol production
    (2017) Singh, Yengkhom Disco
    Due to the long term availability, low cost and easily available of lignocellulosic biomass (LCB) such as agricultural residues and grasses tends to be a sustainable feedstock for production of biofuel and bio-based products. The LCB to biofuel conversion process involves series of significant steps such as pretreatment, hydrolysis and fermentation. However, the biochemical conversion process faces various technical challenges of being contamination with phenolic compounds, aromatics, aliphatic acids, furan aldehydes, inorganic ions, acetic acid, formic acid, levulinic acid, 5-hydroxymethyl-2-furaldehyde (HMF), vanillin, syringaldehyde, conferyl aldehyde and bioalcohol or other fermentation products. Despite of the existing problems and challenges, LCB is considered as one of the most sustainable potential feedstock used for production of biofuel. The feedstock such as Saccharum spontaneum, Phragmites karka, and switch grass has been extensively explored by many researchers for its bioethanol production. To find a new raw material, that can be utilized as feedstock for biofuel production is another challenged in the bioethanol production. In this regard, we aim to explore the LCB found in Kamrup district of Assam and Thoubal district of Manipur of North-East India for biofuel production. The characterization of lignocellulosic biomass gives prior information about the biomass for its fuel content before going through pretreatment and enzymatic saccharification.
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    Design, installation and assessment of a novel variable compression ratio mechanism for multifuel spark ignition engine
    (2017) Chaudhari, Ashish Jagannath
    The spark ignition engines are the most versatile in the arena of internal combustion engines. Petrol fuel based spark igniton(SI) engines are designed for the cylinder bore to stroke ratio(compression ratio), spark plug location which will initiate combustion faster with faster flame speed and develops flame kernel with minimum time during combustion. As per engine manufacturers catalogue, the specified octane petrol is the best for the particular engine. In this regards, if the octane rating of the fuel changed, then the engine will not perform with the maximum efficiency. However, if there are some structural alterations are carried out as per fuel, load and speed, then the higher octane fuel can be utilized to its maximum performance. In order to achieve this objective, the novel variable compression ratio (VCR) mechanism accompanied with novel variable spark plug location (VSPL) is designed and developed which could be installed further on SI engines for online variation of VCR and VSPL. Gaseous fuels are high octane ratings and could be a good source of alternative energy source. Knowing this, the non renewable gas LPG and renewable raw biogas (52% CH4+46% CO2) are being tested in engine for VCR, VSPL and in combination with EGR. The results recommend for continuous variation of CR accompanied with VSPL as per speed, load and EGR level could certainly achieve best performance in case of both fuels.
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    Dilute acid and ionic liquid based pretreatment of lignocellulosic biomass towards fermentable sugars
    (2017) Dash, Madhusmita
    The current study focuses on physico-chemical characterization and pretreatment of three commonly available lignocellulosic biomasses of North-East India such as Castor (Ricinus communis), Jatropha (Jatropha curcas), and Miscanthus (Miscanthus Sinensis) for second generation biofuels production. It was found that the cellulose content of three biomasses varied from 40% to 44%, hemicellulose content from 8% to 14% and lignin content varied from 21% to 30%. Chemical structure of lignocellulose is studied through FTIR. The crystallinity index of Castor and Jatropha was similar, i.e., 69%, whereas crystallinity index of Miscanthus was 72%. Due to the presence of higher carbon and cellulose content along with less moisture (10%–12%), ash (5%–10%), sulphur (0.1%– 0.8%), and extractives (12%–20%) makes them very good feedstock for the production of alcoholic fuels through biochemical route. Thermogravimetric analysis of these three lignocellulosic biomass under high purity nitrogen atmosphere were carried out over a temperature range of 25 oC–900 oC at three different heating rates of 10, 15, 20 oC min–1. The activation energy and pre-exponential factors were calculated by applying two modelfree methods and compared. The kinetic parameters obtained from Kissinger and Ozawa methods were in good agreement with the experimental results. The value of kinetic parameters explained the thermal stability of the biomass. The thermal analysis could not infer the composition and chemical structure of lignocellulosic biomass; hence FTIR spectroscopic analysis has been carried out.