How is hydrogen used as a fuel?
Using hydrogen as a fuel has been an ongoing trouble for years now but lately a new and very efficient way of using hydrogen as a fuel and this is by using a fuel cell.
What is a fuel cell?
A fuel cell is a device that converts the chemical energy from hydrogen into electricity through a chemical reaction. Fuel cells are different from batteries as they require a continuous source of fuel and oxygen or air to sustain the chemical reaction, whereas in a battery the chemicals present in the battery react with each other to generate an electricity. Fuel cells can continuously produce electricity as long as hydrogen and oxygen is supplied. Similar to a battery, a fuel cell contains many compact cells that together form a fuel cell stack. Each individual cell contains an anode, a cathode and an electrolyte. And when a hydrogen-rich fuel enters the fuel cell stack, it reacts electrochemically with oxygen to produce electric current, heat and water.
Ionization - Ionization is the process by which an atom or a molecule acquires a negative or positive charge by gaining or losing electrons to form ions.
Electrolyte- a substance that ionizes when dissolved in ionizing solvents such as water
(http://www.fuelcells.org/base.cgim?template=fuel_cells_and_hydrogen)
(http://www.fuelcellenergy.com/why-fuelcell-energy/how-do-fuel-cells-work/)
What is a fuel cell?
A fuel cell is a device that converts the chemical energy from hydrogen into electricity through a chemical reaction. Fuel cells are different from batteries as they require a continuous source of fuel and oxygen or air to sustain the chemical reaction, whereas in a battery the chemicals present in the battery react with each other to generate an electricity. Fuel cells can continuously produce electricity as long as hydrogen and oxygen is supplied. Similar to a battery, a fuel cell contains many compact cells that together form a fuel cell stack. Each individual cell contains an anode, a cathode and an electrolyte. And when a hydrogen-rich fuel enters the fuel cell stack, it reacts electrochemically with oxygen to produce electric current, heat and water.
Ionization - Ionization is the process by which an atom or a molecule acquires a negative or positive charge by gaining or losing electrons to form ions.
Electrolyte- a substance that ionizes when dissolved in ionizing solvents such as water
(http://www.fuelcells.org/base.cgim?template=fuel_cells_and_hydrogen)
(http://www.fuelcellenergy.com/why-fuelcell-energy/how-do-fuel-cells-work/)
Step to step guide on how a fuel cell works-
- Hydrogen gas gets fed down a pipe to the positive terminal. (Cathode).
- Oxygen from the air gets fed down a second pipe to the negative terminal.(anode)
- The cathode inside the fuel cell is made of platinum, a precious metal catalyst designed to speed up the chemical reaction occurring in the fuel cell. When the hydrogen gas atoms reach the catalyst, they split up into hydrogen ions (protons) and electrons (small black blobs). Hydrogen ions are simply hydrogen atoms with their electrons removed.
- The hydrogen ions, being positively charged, are attracted to the negative terminal and travel through the electrolyte towards it (The electrolyte plays a crucial role in the fuel cell. Permitting only the appropriate ions to pass between the anode and cathode. If the electrolyte is not functioning properly the wrong electrons or other substances travel would through the electrolyte, and disrupt the chemical reaction.)
- While this happens the electrons flow through the outer circuit. Of the fuel cell as they do so, they power the electric motor that drives the car's wheels. Eventually, they arrive at the negative terminal were the protons and electrons recombine with oxygen from the air in a chemical reaction that produces water. (This water is given off from the exhaust pipe as water vapour or steam.)
This type of fuel cell is called a polymer exchange membrane or proton exchange membrane because of how this fuel cell involves an exchange of protons across a polymer membrane). It'll keep running for as long as it is supplied with hydrogen and oxygen. However Since there's always plenty of oxygen in the air, the only limiting factor is how much hydrogen there is in the tank.
(http://www.explainthatstuff.com/fuelcells.html)
- Oxygen from the air gets fed down a second pipe to the negative terminal.(anode)
- The cathode inside the fuel cell is made of platinum, a precious metal catalyst designed to speed up the chemical reaction occurring in the fuel cell. When the hydrogen gas atoms reach the catalyst, they split up into hydrogen ions (protons) and electrons (small black blobs). Hydrogen ions are simply hydrogen atoms with their electrons removed.
- The hydrogen ions, being positively charged, are attracted to the negative terminal and travel through the electrolyte towards it (The electrolyte plays a crucial role in the fuel cell. Permitting only the appropriate ions to pass between the anode and cathode. If the electrolyte is not functioning properly the wrong electrons or other substances travel would through the electrolyte, and disrupt the chemical reaction.)
- While this happens the electrons flow through the outer circuit. Of the fuel cell as they do so, they power the electric motor that drives the car's wheels. Eventually, they arrive at the negative terminal were the protons and electrons recombine with oxygen from the air in a chemical reaction that produces water. (This water is given off from the exhaust pipe as water vapour or steam.)
This type of fuel cell is called a polymer exchange membrane or proton exchange membrane because of how this fuel cell involves an exchange of protons across a polymer membrane). It'll keep running for as long as it is supplied with hydrogen and oxygen. However Since there's always plenty of oxygen in the air, the only limiting factor is how much hydrogen there is in the tank.
(http://www.explainthatstuff.com/fuelcells.html)
What other types of fuel cells are there?
Alkali fuel cells
Alkali fuel cells work on compressed hydrogen and oxygen. And instead of electrolyte it uses a solution of potassium hydroxide (KOH) in water. The Efficiency of this fuel cell is about 70 percent, and the temp needed to operate is 150 to 200 degrees C. The fuel Cells energy output ranges from 300 watts to 5 kilowatts. This fuel cell is most known for being used in the Apollo spacecraft, providing both electricity and drinking water for the astronauts.
Alkali fuel cells work on compressed hydrogen and oxygen. And instead of electrolyte it uses a solution of potassium hydroxide (KOH) in water. The Efficiency of this fuel cell is about 70 percent, and the temp needed to operate is 150 to 200 degrees C. The fuel Cells energy output ranges from 300 watts to 5 kilowatts. This fuel cell is most known for being used in the Apollo spacecraft, providing both electricity and drinking water for the astronauts.
Molten Carbonate
As the Molten carbonate fuel cells electrolyte it uses high-temperature compounds of salt carbonates (chemically, CO3). This fuel calls Efficiency ranges from 60 to 80 percent, this fuel cells energy output can get up to 2 megawatts, and temperature needed for operation is about 650 degrees C. This high temp decreases the emission of carbon monoxide. And the waste heat can be recycled to make additional electricity.
As the Molten carbonate fuel cells electrolyte it uses high-temperature compounds of salt carbonates (chemically, CO3). This fuel calls Efficiency ranges from 60 to 80 percent, this fuel cells energy output can get up to 2 megawatts, and temperature needed for operation is about 650 degrees C. This high temp decreases the emission of carbon monoxide. And the waste heat can be recycled to make additional electricity.
Phosphoric acid fuel cell
Like in the name of this fuel cell (Phosphoric Acid fuel cell) it uses phosphoric acid as the electrolyte. Efficiency ranges from 40 to 80 percent. Temp needed for operation between 150 to 200 degrees C. the fuel cell energy output is up to 200 kW, and 11 MW. This fuel cell can tolerate a carbon monoxide concentration of only 1.5 percent, and because of this, the choice of fuels they can use broadens.
(http://americanhistory.si.edu/fuelcells/basics.htm)