COMPARATIVE ANALYSIS OF UTILIZATION OF HYDROGEN (THROUGH ELECTROLYSIS OF WATER) ALONG WITH DIESEL IN A DIESEL ENGINE
ABSTRACT
The project aims at substituting diesel with hydrogen in a diesel engine .In the current energy scenario the substitution of diesel with some alternate fuel is one of important needs of the day. Main aim is to produce hydrogen from water; the process of electrolysis is selected for this purpose. Water is cheap and plentilly available and thereby the project aims in producing hydrogen from electrolysis and utilizing it in substituting diesel with hydrogen(partially) in diesel engine.Production of hydrogen from a electrolytic cell with various types of Electrodes are tested by trial and error and found that production of hydrogen produced from aluminum electrodes was found to be more volumetrically and also advantageous in many ways.The gas produced in the cathode was confirmed as hydrogen and combustible. It is mixed with diesel in the inlet manifold of the engine. Comparative load tests done with pure hydrogen and diesel and hydrogen in dual mode. Readings are taken for fuel consumption with respect to time at various loads. Graphs are plotted to depict comparative analysis.Project aims in developing a new era of alternative fuels and aims in developing new such methods in near future in the field of energy development. The main aim of selecting a boat engine to do the load test is to implement this technology to help the economically weaker section. Our technology has to somehow help the poorest of the poor.
INTRODUCTION
In the current energy scenario the depletion of fossil fuels and increase in pollution compels us to go for some alternated energy sources. Alternative fuels for internal combustion engines, such as LPG, natural gas, ethanol etc have been the topics of the day. Considering the pollutant emissions by hydrocarbon fuels, the green house effect and the unsure uncertainty hydrocarbon depleting of energy supply, hydrogen is considered as the best fuel for the future.Hydrogen is one of the most promising future fuels for internal combustion engines. Hydrogen has highest energy content per unit weight (lower heating value of 119.7 MJ/kg), wide range of flammability (operation on lean mixtures) etc make it a desirable for automotive purposes. However some problems related to premature ignition, backlash, low density need to be addressed. The various methods for hydrogen production include processes based on fossil fuels (steam reforming of natural gas, catalytic decomposition of natural gas, partial oxidation of heavy oil, coal gasification), water electrolysis, photochemical cycles etc. Hydrogen in high purity can be produced through the electrolysis of water. Electrolytic hydrogen production has been the focus of much technical and economic investigation due to its significant future prospects. Hydrogen production via electrolysis of alkaline aqueous electrolytes can be used to make electrolysers, which can supply hydrogen and oxygen gas, which can be stored and used for various purposes. Commercial stainless steel or nickel-based alloys in alkaline solutions can be utilized for making them. We aim in using water as electrolyser and aluminum electrodes.
The first hydrogen engine was developed by R. W. Cecil in 1820, which operated on vacuum principle. In this engine atmospheric pressure drives a piston back against a vacuum, created by burning hydrogen air mixture allowing it to expand and then cool, to produce power. Because of its high energy to weight ratio, it is extensively used in space program. The energy crisis, with the rapidly dwindling resources of gasoline and diesel, has necessitated the requirement to develop rapidly, alternative sources of energy to power the automobiles. Research is on for utilizing hydrogen as an automotive propellant on a commercial scale. Researchers and industries have directed their efforts to numerous aspects of hydrogen energy related to generation, storage and utilization of hydrogen.Marcelo et al. [1] investigated the hydrogen evolution reaction on different stainless steels. The work highlights how it is possible to produce hydrogen in economical ways using less advanced technologies. They built a conventional alkaline electrolytic cell using economical material and compared the cost of the device with the cost of electrolysers available in the market. They found a big margin for costs decreasing even taking into account all the auxiliary systems for an electrolysis process.
Nagai et al. [2] experimentally investigated the effect of bubbles on efficiency of hydrogen by water electrolysis. Ni-Cr-Fe alloy was used as electrodes with potassium hydroxide aqueous solution as electrolyte. The current density, with or without separator, system temperature, space, height, inclination angle and surface wettability of electrodes were controlled for the experiment conducted under atmospheric pressure. They found that there is an optimum condition of water electrolysis at a certain current density. A physical model of void fraction between electrodes was also presented.
Ulleberg [3] developed a mathematical model for an alkaline electrolyser and used the same to predict cell voltage, hydrogen production, efficiencies, and operating temperature. The model can be particularly useful for system design or redesign and optimization of control strategies. Improved electrolyser operating strategies can be identified with the developed system simulation model.
Dragica et al. [4], in his work, used ionic activators to reduce the energy consumption in electrolysis and to improve the process. Use of ionic activators showed significant catalytic effects and thus corresponding energy saving per mass unit of electrolytically evolved hydrogen from alkaline aqueous solutions. Two types of activators, both ethylenediamine complexes of cobalt, were used separately or in combination with some molybdates. For some cases up to 10% reduction in energy needs were found.
Vishwanath [5] studied the electrolysis of water using polished platinum as electrodes in a divided electrolytic cell. A chemically treated disc separator was used to divide the cell which allows only current to pass through hand does not allow ions to move from one compartment to the other, permitting one to apply chemical bias. He has demonstrated the splitting of water into hydrogen and oxygen at as low a potential as 1.0 volt and thus applied for a patent. This could be used to build hydrogen cars with a pack of electrolytic cells and hydrogen fuel cells where only electrolytic solution has to be added for running the IC engine thus eliminating the intermediate hydrogen storage.
Bohacik et al. [6] in his work evaluates and discusses the combustion characteristics of electrolytically produced stoichiometric hydrogen-oxygen mixtures under constant volume adiabatic conditions. The maximum combustion pressures were investigated and compared with theoretical predictions based on first law of thermodynamics, ideal gas laws and adiabatic flame temperature. They found the experimental results to be within 10% of theoretical predictions. The ignition delay time and rate of pressure rise were also investigated and concluded that the combustion chambers of hydrocarbon fuelled engines are not compatible with hydrogen engines.
Sierens et al. [7], in his work, adapted a V-8 spark ignited engine for gaseous fuels. They performed the first tests with external mixture formation (venturi type) system and later on with sequential timed multi point injection of hydrogen. This resulted in the complete control of combustion process, as an electronic management system was chosen, and increased the power output of the engine without danger of backfire. Specific features of the use of hydrogen in IC engines is analysed such as the necessity of smaller spark plugs, deterioration of lubricating oil. The advantages and disadvantages of a power regulation only by the air to fuel ration against a throttle regulation are examined.
Mahesh et al. [8], in his work, reports the various technologies that have been used over the years for inducing hydrogen into the combustion chamber of the IC engine. The principles behind these technologies, their advantages and their drawbacks have been elaborated. They concluded that the selection of the appropriate hydrogen induction method depends on the mode of operation of the hydrogen engine. The operating conditions, power output, cost and various other factors need to be given due consideration for the selection of an injection system. They also developed the hydrogen induction methodologies matrix which can be used to select the induction technology that is most appropriate for the particular application.
- A. Rosen [9] used energy and exergy analysis to examine the thermodynamic performance of a water electrolysis process for producing hydrogen. The work gives a better understanding of the process, its operational efficiency, and possible improvements. The analysis indicates that, when the main driving input is the hypothetical heat source, the losses are mainly due to the irreversibilities associated with converting a heat source to heat, and heat transfer across large temperature differences.
Ganesh et al. [10] investigated the performance of a hydrogen fueled spark ignition engine using timed manifold fuel injection technique. They used a solenoid operated gas injector to inject hydrogen into the manifold at the specified time. The results were compared with engine run on gasoline and they found an improvement of 2% in the brake thermal efficiency. With hydrogen operation, HC emissions were negligible. NO levels were significantly higher than that of gasoline operation. They concluded that reducing the injection duration can overcome the problem of backfiring at high power outputs and suggested suitable methods to control knock so that the maximum power output can be further improved.
Stefaan et al. [11] studied the performance of a single cylinder hydrogen fuelled internal combustion engine. They found that the spark ignition engines is very suitable for the use of hydrogen as fuel by taking into account the hydrogen specific properties. In their testing, they found that a toque deficit of 30 % is there when compared to methane and high emission levels of NOx at high loads. Boosting the inlet charge to restore the torque output and exhaust gas recirculation are some of the methods suggested by the author in order to overcome the drawbacks.
Subramanian et al. [12] conducted experiments on a single cylinder, three wheeler, spark ignition engine operating with hydrogen as fuel. In their work, the hydrogen was inducted through the intake manifold to the engine. The engine was always operated with wide open throttle and the equivalence ration was varied to change the output. Experiments were also conducted with gasoline as fuel with conventional carburettor to compare the results. They found that the maximum power produced by hydrogen engine was less than that of gasoline. However the hydrogen engine gave higher efficiency at optimised conditions at all operating points. The main drawback was the increased NOx emissions at high loads due to increased temperature.
Saravanan et al. [13] investigated the use of hydrogen as a dual fuel for a single cylinder, water cooled direct injection diesel engine with exhaust gas recirculation. Hydrogen enriched air was used as the intake charge in a diesel engine adopting exhaust gas recirculation with H2 flow at 20 lpm. They found an improvement of 6 % in brake thermal efficiency with hydrogen as compared to diesel. EGR helped in reducing the NOx concentration as peak combustion temperatures were reduced. Hydrogen usage also gave cleaner combustion with reduced carbon monoxide and hydrocarbon emissions.
Nowontny et al. [14] investigated on the unresolved problems in the solar hydrogen generation field, particularly the development of photo-electrodes for photo-electrochemical generation of hydrogen from water using solar energy. Their work is focused on photo-electrodes based on oxide semiconductors, including TiO2 and TiO2-based materials, which are the most promising candidates for photo-electrodes. The effect of disorder on the performance related properties of TiO2 are discussed and concludes that the defect chemistry may be used as a frame work for engineering novel photo-sensitive materials. They also suggest that even though the price of solar hydrogen is higher, it will be compensated by the reduction in pollution and global warming.
Michel et al. [15] focuses on the on-board storage methods for liquid hydrogen vehicles such as passenger cars and buses. The recent solutions for the on-board storage and supply of the liquid fuel for different vehicles and driving systems have been analysed. The work also describes the systems for improved pressure management and testing of these components.
Dornheim et al. [16] investigated on the hydrogen storage methods in magnesium based hydrides and hydride composites. These have much attention because of their high gravimetric hydrogen storage densities and favourable kinetic properties. Their work summarises the recent developments in sorption properties and the thermodynamics of Mg-based hydrides, for hydrogen storage applications. They found that alloying with 3d transition metals can lead to a reduction of the reaction enthalpy, however with a reduction in gravimetric density. Magnesium based reactive hydride composites promises to be the future material as they help in reducing reaction enthalpies while achieving very high storage capacity. They however suffer from slow sorption kinetics.
- K. Ross [17] reviews the current technology for the storage of hydrogen on board a fuel cell-propelled vehicle. He outlines the inherent difficulties with the gs pressure and liquid hydrogen storage. The author also investigates on the various possibilities of making magnesium hydride decompose and reform more readily. He concludes that systems with stronger interactions will inevitable require a surface interaction that increases the molecular hydrogen-hydrogen distance.