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Water Power Project

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by

Haider Mehdi

on 12 August 2013

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Transcript of Water Power Project

At Cathode, Hydrogen gases are prodeced
Is Water A Good Source?
Water may be one of the most familiar substances on the planet, but it certainly isn’t ordinary. In fact, water’s unique chemical properties make it so complicated that even after decades of research, scientists still have much to learn about this remarkable and versatile substance.
Water consists of an oxygen atom bound to two hydrogen atoms by two single covalent bonds.
Oxygen has unpaired & paired electrons which gives it a slightly negative charge while Hydrogen has no unpaired electrons and shares all others with Oxygen leaves molecule with positively and negative charged ends
Electrolysis of water is an electrochemical process which decomposes water into oxygen and hydrogen gas with the aid of an electric current. Production of hydrogen from water requires large amounts of energy and is uncompetitive with production from coal or natural gas. Potential electrical energy supplies include hydro power, wind turbines, or photovoltaic cells.
A variety of different materials react with water or acids to release
hydrogen. For example In the presence of Sodium hydroxide and Aluminum and its alloys react with water to generate hydrogen gas
Al + 3 H2O + NaOH → NaAl(OH)4 + 1.5 H2
3) Water Electrolysis:
2) Chemical Reactions:
1) Thermal Decomposition :
This method is also called thermolysis. At elevated temperatures water
molecules split into their atomic components hydrogen and oxygen.
For example at 2200 °C about three percent of all H2O molecules are
dissociated into various combinations of hydrogen and oxygen atoms,
mostly H, H2, O, O2, and OH. Other reaction products like H2O2 or HO2
remain minor.
At the very high temperature of 3000 °C more than half of the water
molecules are decomposed
Methods For Decomposition of
Water
(cc) image by nuonsolarteam on Flickr
Thermal Decomposition
For thermal decomposition, a huge amount of
heat is required to reach the temperature of 3000°C.
It is a very high temperature and is impossible to achieve and maintain.
Chemical Reaction
Such methods are non-sustainable. Because when metal reacts with water, exothermic reaction will take place, and hydrogen gas will produce. But here the metal act as compact hydrogen storage material. For example1 kg of aluminum can produce up to 0.111 kg of hydrogen (or 11.1%) from water.
Water Electrolysis
Water electrolysis is also one of the most expensive method, it requires huge amount of electrical energy to decompose water.
Water Electrolysis
Water Electrolysis
Chemical Reaction
Thermal decomposition
Continues method can easily be achieved is we continually provide external energy sources
Continues method can not be possible because the reaction is not sustainable
Continues method can only be possible if we maintain such high temperature.
This method also require external energy source.
For this method we need continues source of expensive metal.
To achieve this method we need some sort of heater to provide energy for water decomposition. So we will need an external energy source.
Highly pure gases are obtained.
In this method metallic hydrides are obtained.
Purity is not trustable in this method.
Expansive method require huge amount of current, but can be easily achieved from photo cell.
Unsustainable method, can not be used for perpetual or continues source of energy.
Very expansive and impossible to achieve such a high temperature in vehicle
Electrolysis is suitable among
all those methods
Current Source:
From our calculation we just require 1.23 volts and 192.7Ampere for one mole of water to decompose.
Therefore we require heavy source of electrical current to get
such high value of Ampere
Anode Electrode
Cathode Electrodes
Hydrogen gas Formation
Oxygen Production
Energy Source & Present Era
The vast majority of transportation nowadays is powered by fossil fuels.

Many scientists have agreed that the use of these fossil fuels has caused global warming due to atmospheric effects. This affected by the horrible side effects such as black lung disease,

In response to the negative effects of fossil fuel consumption, the present generation is fighting to head in a different direction.

A future is desired in which the energy used to power the vehicles is renewable and clean.
Is Hydrogen A Good Fuel
Hydrogen gas (molecular hydrogen) is highly flammable and will burn in air at a very wide range of concentrations between 4% and 75% by volume .The enthalpy of combustion for hydrogen is −286 kJ/mol.

When two moles of hydrogen gas react with one mole of oxygen gas, one mole of water form and 286kJ/mole of energy is given off. This suggests that hydrogen is an excellent fuel. Burning one gram of hydrogen produces -286kJ/mole of energy.

Among all fuels, H2 has the highest specific enthalpy (its standard enthalpy of combustion divided by its mass) but has a very low energy density (its standard enthalpy of combustion divided by its volume).
Hydrogen is a gas with physical and chemical properties recommended for use as fuel for thermodynamic engines and plants;

A very important ecological advantage is that Hydrogen combustion does not produce CO2 or SO2, noxious gases or greenhouse gas (CO2). In its combustion with air, it can produce nitrogen oxides (NOx) which are noxious gases and greenhouse gases, but the actual technological level ensures minimal NOx content in the flue gases.

Hydrogen combustion produces water vapors almost exclusively, and they are not noxious.
Problem
. Hydrogen is not found in a free state in nature. Thus we cannot speak of Hydrogen as a primary source, as are conventional fuels. To obtain Hydrogen from the substances in which it occurs, another form of energy must first be consumed. For this reason, Hydrogen is in fact an energy vector from its production source (most desirable without producing atmospheric pollution), to the point at which it is used as a fuel.
Hydrogen Extraction
Steam reforming
Hydrogen can be generated from natural gas with approximately 80% efficiency, or from other hydrocarbons to a varying degree of efficiency.
CH4 + H2O CO + 3 H2 + 191.7 kJ/mol
Coal
Coal can be converted into syngas and methane, also known as town gas, via coal gasification. Syngas consists of hydrogen and carbon monoxide
Biological Production
Biological hydrogen production is mainly done in bio reactors and is based on hydrogen production by some algae.
From Water
Water is a chemical product of hydrogen and oxygen. Hydrogen can be extracted from water by applying different physical and chemical process.
According to our research, Nickel is best electrode for water electrolysis
due to its high conductivity.

Anode is +ve charged plate, during electrolysis oxygen ions are deposited over it.

After denoting two electrons to the anode, oxygen gas will arise freely in bubbles form.
Cathode will also be used with the same material i.e Nickel

Cathode is -ve plate, Hydrogen ions will be deposited over it
and after gaining an electron, Hydrogen will flow freely in the
form of bubbles
Pure water is poor conductor of electricity. Electrons can not flow through it. Therefore we have to use such substance i.e electrolyte which makes water conductive. The electrolyte may be acid, base, or salt.

We have to choose those electrolyte which can not affect electrodes and does not release harmful or poisonous gas as by product. For example table salt can not be used because it releases Chlorine which is highly poisonous gas. Similarly Sulfuric acid can significantly affect electrodes and also releases sulfur dioxide gas.

We use Potassium hydroxide, a strong base that does not affect electrodes and release harmful gases.
Electrolytes
Pure Hydrogen gas is collected over the cathode plate.
The volume of the gas is measured by introducing a test tube placing inverted over cathode plate. As the hydrogen generates, water level in the test tube will decrease proportionally.
Oxygen gas is produced at anode plate.
Calculations
From calculation, it is clear that we need a powerful a external source to get appropriate amount of hydrogen gas.

The source must be perceptual, continuous and reliable.

The source must not be so expensive.
External Energy Source
Photo Cell
External Source
Water powered vehicle
Engine Calculation
Air/Fuel Ratio
From Our Calculation For complete combustion of hydrogen gas, the Air/Fuel requires 34.33:1. It means that 34.33g of air requires 1g of hydrogen gas.This value is much higher than gasoline i.e. 14.7:1


Since the power of the engine depends upon the air/fuel ratio and fuel injection method. The A/F ratio of hydrogen engine is 34:1. Since hydrogen is a gaseous fuel at ambient conditions it displaces more of the combustion chamber than a liquid fuel. Consequently less of the combustion chamber can be occupied by air. At stoichiometric conditions, hydrogen displaces about 30% of the combustion chamber, compared to about 1 to 2% for gasoline
Engine Requirements
we assumed a 70cc 4-stroke engine having bore and stroke length are
50cm and 59cm respectively.

If the engine rotates at rate 3000rpm and torque 10N-m, we require 0.000060375kg fuel (i.e hydrogen).
`
Engine Modification
The power output of a direct injected hydrogen engine vehicle is 20% more than for a gasoline engine vehicle. Hydrogen IC engines work in the similar manner and has same appearance as that of the conventional IC engine.
These are the some factors or area where the modification is required.
1) Pre-Ignition problem
2) Crankcase Ventilation
3) Crankshaft
4) NOx generation
Pre-Ignition problem
Pre-ignition occurs when the fuel mixture in the combustion chamber becomes ignited before ignition by the spark plug, and results in an inefficient, rough running engine. Backfire conditions can also develop if the premature ignition occurs near the fuel intake valve and the resultant flame travels back into the induction system.
This problem can be solved by installing exhaust gas recirculation (EGR) or water injection. As the name implies, an EGR system recalculates a portion of the exhaust gases back into the intake manifold. The introduction of exhaust gases helps to reduce the temperature of hot spots, reducing the possibility of pre-ignition
Crankcase ventilation is even more important for hydrogen engines than for gasoline engines.
As with gasoline engines, unburnt fuel can seep by the piston rings and enter the crankcase. Since hydrogen has a lower energy ignition limit than gasoline, any unburnt hydrogen entering the crankcase has a greater chance of igniting. Hydrogen should be prevented from accumulating through ventilation.
Exhaust gases can also seep by the piston rings into the crankcase. Since hydrogen exhaust is water vapor, water can condense in the crankcase when proper ventilation is not provided. The mixing of water into the crankcase oil reduces its lubrication ability, resulting in a higher degree of engine wear.
Crankcase Ventilation
When the hydrogen ignites,
Crankshaft must be strong
Ignition of hydrogen produces NOx greater than the gasoline. This problem can be solved by installing EGR system in vehicle
NOx Emission
5) Hydrogen Leakage
Hydrogen occupies very large space and therefore can leak from any unseen small opening. Therefore we have to place hydrogen sensors near electrolyzer and engine.
Hydrogen Leakage
Our Design
Overall Working
Our Vehicle Design
Power Output
Project Cost
Engine 70cc 5000 Rupees
Electrolyzer 1000
Nickel plates 2500 Rupees
KOH soln. 200 Rupees
water tank 100 Rupees
Solar panel 18000 rupees
Fabrication 12000 rupees
Hydrogen sensor 10,000 rupees
Engine Modification
Other

Electricity produced by solar cells is clean and silent. Because they do not use fuel other than sunshine,
PV systems do not release any harmful air or water pollution into the environment, deplete natural resources, or endanger animal or human health
Solar cells last a longer time and have low running costs.
The average life of solar cell is 25 years. It means we can produce electricty for 25 years without any cost.
Is Photo panel perfect?
One of the major problem of using solar pannel is that, it is expensive
Electrolyzer Design
Advantages Of Hydrogen Over Other Fuels
Overall Calculation
Full transcript