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Abstract Hydrogen manufacturing technologies that employ water to produce pure hydrogen and oxygen via thermal, electrolytic, photolytic, and chemical conversion of biomass water splitting. Due to its widespread availability water is considered a sustainable feedstock for hydrogen production. The production of hydrogen from water has the potential to significantly reduce the depletion of fossil fuels and CO2 emissions. Hydrogen is produced through water electrolysis, where an electrical current splits water into its components of Hydrogen and Oxygen, Due to its eco-friendly production and its potential for powering heavy industry and transport, many experts think Green Hydrogen will become an increasingly significant energy source. The study is divided into four chapters: Chapter one: introduction and literature review: This chapter include a general idea about the main properties of hydrogen gas, importance of hydrogen as a fuel, electrolysis different techniques, different methods of hydrogen production and storage. Literature review on electrolysis different techniques, different methods of hydrogen production, and recent references related to the research has been used. Chapter two This chapter include the electrolyzer design, components, idea of work, measured and calculated parameters, and explement technique for measurements of evolved gasses. Commercial electrolysis usually consists of a number of electrolytic cells arranged in a cell stack. The major challenge for the future is to design and manufacture electrolysis equipment at lower costs with higher energy efficiency and larger turn-down ratios. A new cell is proposed based on the following system: Cathode: stainless steel 316L (chemical resistant) Anode: stainless steel 316L (chemical resistant) The experimental work will have the objective of maximizing the cell efficiency by studying the different parameters affecting the cell performance which can be summarized in the following measured values: a) Electrode structure and size (fixed bed cylinders aspect ratio (1:1). b) Temperature (55, 65, 75 0C). c) Flow parameters (flow rate for anolyte and catholyte). SUMMARY 234 d) Concentration of alkali. e) Current density. The cell efficiency will be evaluated through measuring the amount of produced hydrogen gas with studying the effect of the above parameters on energy requirements such as consumed power, energy density, ampere hour, and KWh/kg of hydrogen gas. The experimental apparatus used in the present study consisted mainly of fixed bed reactor, flow circuit and electrical circuit. The reactor consisted of two cubic compartments of plexi-glass (poly amide). The reactor is divided into three sections: inlet section, outlet section, the working section, the inlet and outlet sections consist of plastic pipes with valves for each section to control the flow rate within turbulent region which assist to increase the mass transfer coefficient. The working section consist of two cubic compartments separated by cation exchange membrane which allow the passage of only hydrogen ions, the anode compartment contain a fixed bed stainless steel 316L acting as anode, while the cathode compartment consist of a fixed bed stainless steel 316L, the alkaline water solution was pumped from one storage tank to the two half cells with very high surface area which assist to increase the mass transfer coefficient, hydrogen and oxygen evolved under applied electrical current, hydrogen and oxygen collected in plexi-glass storage tanks connected to gas flow meter and pressure gauge. The electrical circuit consisted of a 12 volts D.C. power supply, variable resistance, a multi range ammeter connected in series with the cell, high impedance voltmeter was connected in parallel with the circuit to measure the cell voltage. Chapter three This chapter include measured and calculated results, the effects of different operating conditions on electrolyzer efficiency. The effect of current density was investigated by conducting experiments at, 4 mA/cm2 , 6 mA/cm2 , and 8 mA/cm2 . The temperature was also varied (55 oC, 65 oC, and 75 oC) which resulted in an increase in the cell efficiency from 8.3% to 96.6%. The present study investigates the effect of different variables on cell performance. The different variables investigated included: solution concentration, current density, solution flow rate, rod size and temperature. The resulting flow rate of produced hydrogen and oxygen gas, the effect of electrolyte solution flow rate, solution concentration, and solution temperature on cell voltage were evaluated. The produced oxygen gas, power consumption, energy consumption, and ampere hour capacity are calculated, and the cell efficiency is therefore evaluated by comparing the theoretical and experimental mass flow rates of hydrogen gas. Additionally, Elevation of electrolyte temperature reduces energy density consumption from 732 kWh/kg of H2 to 52.9 kWh/kg, SUMMARY 235 The higher efficiencies values appears at rod size 10 mm, higher concentrations of 2 M and 1.5 M at temperature 75 0C and smaller current density of 4 mA/cm2 and reaches96.6%, whereas the lower values (8.3% to 20%) appear at rod size 15 mm, lower concentration of 1 M, lower temperature 55 0C, lower flow rates of electrolyte solution 1L/min, and the characterization of electrodes before and after the experiment was done using scanning electron microscopy (SEM) examination and alloy composition elemental Mapping which prove that low cost stainless steel 316L can be used in future work in alkaline water electrolysis with high efficiency and will help in the reduction of electrolysis cost rather than other Nobel metals . Chapter four This chapter contains the final conclusions which are approved by measured and calculated records listed in tables (3.1) and (3.2) |