Hydrogen as energy sources

Hydrogen as energy sources
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Hydrogen is the chemical element with atomic number 1. It is represented by the symbol H. At standard temperature and pressure, hydrogen is a colorless, odorless, nonmetallic, tasteless, highly flammable diatomic gas with the molecular formula H2. With an atomic weight of 1.00794 u, hydrogen is the lightest element.

Hydrogen is the simplest element known to man. Each atom of hydrogen has only one proton. It is also the most plentiful gas in the universe. Stars are made primarily of hydrogen.



The sun is basically a giant ball of hydrogen and helium gases. In the sun’s core, hydrogen atoms combine to form helium atoms. This process is called fusion and gives off radiant energy. This radiant energy sustains life on earth. It gives us light and makes plants grow. It makes the wind blow and rain fall. It is stored as chemical energy in fossil fuels. Most of the energy we use today came from the sun’s radiant energy.

Hydrogen has the highest energy content of any common fuel by weight (about three times more than gasoline), but the lowest energy content by volume (about four times less than gasoline). It is the lightest element, and it is a gas at normal temperature and pressure.

hydrogen moleculeHydrogen gas is lighter than air and, as a result, it rises in the atmosphere. This is why hydrogen as a gas (H2) is not found by itself on earth. It is found only in compound form with other elements. Hydrogen combined with oxygen, is water (H2O). Hydrogen combined with carbon, forms different compounds such as methane (CH4), coal, and petroleum. Hydrogen is also found in all growing things—biomass. It is also an abundant element in the earth’s crust.

Like electricity, hydrogen is an energy carrier and must be produced from another substance. Hydrogen is not widely used today but it has great potential as an energy carrier in the future. Hydrogen can be produced from a variety of resources (water, fossil fuels, biomass) and is a byproduct of other chemical processes. Unlike electricity, large quantities of hydrogen can be easily stored to be used in the future. Hydrogen can also be used in places where it’s hard to use electricity. Hydrogen can store the energy until it’s needed and can be moved to where it’s needed.

 

How it is made
Since hydrogen doesn’t exist on earth as a gas, we must separate it from other elements. We can separate hydrogen atoms from water, biomass, or natural gas molecules.

The two most common methods for producing hydrogen are steam reforming and electrolysis (water splitting). Scientists have even discovered that some algae and bacteria give off hydrogen.

Steam reforming
It is used in industries to separate hydrogen atoms from carbon atoms in methane(CH4). Because methane is a fossil fuel, the process of steam reforming results in greenhouse gas emissions that are linked with global warming.

Electrolysis
It is a process that splits hydrogen from water. It results in no emissions but it is currently a very expensive process. New technologies are being developed all the time.

Hydrogen can be produced at large central facilities or at small plants for local use. Every region of the country (and the world) has some resource that can be used to make hydrogen. Its flexibility is one of its main advantages.

 

Usage
Hydrogen fuel cells (batteries) make electricity. They are very efficient, but expensive to build. Small fuel cells can power electric cars. Large fuel cells can provide electricity in out of the way places with no power lines.

Hydrogen poses a number of hazards to human safety, from potential detonations and fires when mixed with air to being an asphyxant in its pure, oxygen-free form. In addition, liquid hydrogen is a cryogen and presents dangers (such as frostbite) associated with very cold liquids. Hydrogen dissolves in some metals, and, in addition to leaking out, may have adverse effects on them, such as hydrogen embrittlement. Hydrogen gas leaking into external air may spontaneously ignite. Moreover, hydrogen fire, while being extremely hot, is almost invisible, and thus can lead to accidental burns.

Large quantities of H2 are needed in the petroleum and chemical industries. The largest application of H2 is for the processing (“upgrading”) of fossil fuels, and in the production of ammonia. H2 is also used as a reducing agent of metallic ores.

Hydrogen is used pure or mixed with nitrogen (sometimes called forming gas) as a tracer gas for minute leak detection. Applicable in the automotive, chemical, power generation, aerospace, and telecommunications industries. Hydrogen is an authorized food additive (E 949) that allows food package leak testing among other anti-oxidizing properties.

Nitrate
Nitrate (NO3-) is an extremely soluble form of nitrogen. It does not bind with the surfaces of clay minerals nor does it form insoluble compounds with other elements that it encounters when moving through the soil. Because nitrate is soluble, it can readily move with soil water toward plant roots to be taken up by them. However, if there is a large amount of water entering and passing through the soil root zone, NO3- can be carried by percolating water beyond the soil root zone.

Nitrate leaching can have a direct impact on water quality. Nitrate is very mobile and easily leaches with water. Heavy rains can cause nitrates to leach downward in the soil below the root zone.

Once nitrates get into the groundwater, the greatest concerns are for infants less than one year old and for young or pregnant animals. High levels of nitrates can be toxic to newborns, causing anoxia, or internal suffocation. Seek alternative water sources if nitrate levels exceed the health standard of 10 ppm nitrate-N. Do not boil water to eliminate nitrates. It increases nitrate levels rather than decreasing them. The most common symptom of nitrate poisoning in babies is a bluish color to the skin, particularly around the baby’s eyes and mouth. These symptoms of nitrate toxicity are commonly referred to as the “blue-baby” syndrome.

 

Health effect
Nitrates and nitrites cause several health effects:

Reactions with haemoglobin in blood, causing the oxygen carrying capacity of the blood to decrease (nitrite)

  •     Decreased functioning of the thyroid gland (nitrate)
  •     Vitamin A shortages (nitrate)
  •     Fashioning of nitro amines, which are known as one of the most common causes of cancer (nitrates and nitrites)

From a metabolic point of view, nitric oxide (NO) is much more important than nitrogen alone. In 1987, Salvador Moncada discovered that this was a vital body messenger for relaxing muscles, and today we know that it is involved in the cardiovascular system, the immune system, the central nervous system and the peripheral nervous system. The enzyme that produces nitric oxide, called nitric oxide synthesis, is abundant in the brain.

Nitrogen – environmental effect
The main cause of the addition of nitrates and nitrites is the extensive use of fertilizers. Combustion processes can also enhance the nitrate and nitrite supplies, due to the emission of nitrogen oxides that can be converted to nitrates and nitrites in the environment.

Nitrates and nitrites also form during chemical production and they are used as food conservers. This causes groundwater and surface water nitrogen concentration, and nitrogen in food to increase greatly.

The addition of nitrogen bonds in the environment has various effects. Firstly, it can change the composition of species due to susceptibility of certain organisms to the consequences of nitrogen compounds. Secondly, mainly nitrite may cause various health effects in humans and animals. Food that is rich in nitrogen compounds can cause the oxygen transport of the blood to decrease, which can have serious consequences for cattle.

High nitrogen uptake can cause problems in the thyroid gland and it can lead to vitamin A shortages. In the animal stomach and intestines nitrates can form nitroamines; dangerously carcinogenic compounds.