Hydrogen is widely used in various industries: in the synthesis of hydrogen chloride, ammonia (ammonia is further used for the production of nitrogen fertilizers), in the aniline-paint production, and during the recovery from non-ferrous metals. In the food industry, it is used to obtain substitutes for animal fats (margarines). In connection with the above relevant issue is the production of hydrogen in an industrial environment.
This gas is considered as a future energy carrier due to the fact that it is renewable, does not emit “greenhouse gas” CO₂ during combustion, gives a large amount of energy per unit weight during combustion, and is easily converted into electricity from fuel cells.
In laboratory conditions, hydrogen is most often obtained by reduction by metals, which are to the left in the electrochemical series of voltages, from water and acids:
Zn + 1HCl = ZnCl₂ + H₂ ↑: ΔH <0
2Na + 2HOH = 2NaOH + H₂ ↑: ΔH <0.
In industry, the production of hydrogen occurs mainly through the processing of natural and associated gases.
1. Methane conversion. The process consists in the interaction of methane with water vapor at 800 - 900 ° : CH₄ + H₂O = CO ↑ + 3H₂ ↑; ΔH> 0. Along with this, the process of incomplete oxidation of hydrocarbons by oxygen in the presence of water vapor is used: 3CH₄ + O₂ + H₂O = 3CO + 7 H₄. These methods will lose their value over time as hydrocarbon reserves are depleted.
2. Biohydrogen can be obtained from seaweed in a bioreactor. In the late 1990s, it was discovered that if algae was deprived of sulfur, they would switch from the production of oxygen, i.e., normal photosynthesis, to the production of hydrogen. Biohydrogen can also be produced in bioreactors using, in addition to algae, household waste. The process is due to bacteria that absorb hydrocarbons and produce hydrogen and CO2.
3. Deep cooling of coke oven gas. During the coking process of coal, three fractions are obtained: solid - coke, liquid - coal tar - and gaseous, containing, in addition to hydrocarbons, molecular hydrogen (about 60%). This fraction is subjected to ultra-deep cooling after being treated with a special substance, which makes it possible to separate hydrogen from impurities.
4. Hydrogen production from water using electrolysis - a method that produces the purest hydrogen: 2H₂O → electrolysis → 2H₂ + O.
5. The conversion of carbon. First, water gas is obtained by passing water vapor through coke heated to 1000 ° : C + H₂O = CO ↑ + H₂ ↑; ΔH> 0, which is then passed in a mixture with water vapor over a Fe₂O₃ catalyst heated to 400–500 ° . The interaction of carbon monoxide (II) and water vapor occurs: CO + H₂O + (H₂) = CO₂ + 2H₂ ↑; ΔH> 0.
6. Hydrogen production by conversion of carbon monoxide (CO), based on a unique reaction using photosynthetic purple bacteria (unicellular microorganisms of a peculiar red or pink color, which is associated with the presence of photosynthesis pigments). These bacteria produce hydrogen as a result of the conversion reaction: CO + H₂O → CO₂ + H₂.
The formation of hydrogen comes from water, the reaction does not require high temperatures and lighting. The process takes place at room temperature in the dark.
Of great industrial importance these days is the evolution of hydrogen from the gases generated during oil refining.
However, many do not know that it is possible to produce hydrogen at home. For these purposes, you can use the reaction of a solution of alkali and aluminum. Take a half-liter glass bottle, a cork with a hole, a gas pipe, 10 g of copper sulfate, 20 g of salt, 10 g of aluminum, 200 g of water, a balloon.
We prepare a solution of copper sulfate: add 100 g of copper sulfate to 100 g of water.
We prepare a saline solution: add 100 g of salt to 100 g of water.
Mix the solutions. Add aluminum to the resulting mixture. After a white suspension has appeared in the bottle, we attach the ball to the tube and fill it with the liberated hydrogen.
Note! This experiment should be carried out only in the fresh air. Temperature control is required, as the reaction occurs with the release of heat and can get out of control.
It should also be remembered that hydrogen, if mixed with air, forms an explosive mixture called explosive gas (two parts of hydrogen and one part of oxygen). If such a mixture is ignited, then it will explode.