Urea plays an important role in the metabolism of nitrogen-containing compounds in the animal body, and at the same time, it is the main nitrogen-containing substance in the urine of mammals. This compound is: hard, colorless, odorless (although the ammonia produced from it in the presence of water, which includes water vapor in the air, has a pungent odor), neither acidic nor alkaline, very soluble in water, and relatively It is non-toxic, urea is widely used in chemical fertilizers as a rich and suitable source of nitrogen. Urea is also one of the important raw materials in the chemical industry. The synthesis and creation of this organic compound from an inorganic or mineral precursor, by Friedrich Wöhler in 1828, is considered a very important milestone in the development and progress of chemical knowledge.
Urea was first discovered in urine in 1773 by a French chemist named Hilaire Rouelle. In 1828, the German chemist Friedrich Wöhler, during an unsuccessful attempt to prepare ammonium cyanate, obtained urea when he added ammonium chloride to silver isocyanate: this was the first time that an organic compound was synthesized from inorganic precursors. (mineral) is synthesized, without organisms or living beings having any involvement in this process. Understanding this issue played a very important role in the development of organic chemistry. Many believe that Wehler should be considered the father of organic chemistry because of this discovery.
More than 90% of urea production in the world contains nitrogen for use as chemical fertilizers. In general applications, urea has the highest amount of nitrogen among all solid nitrogen fertilizers (46.7%). Accordingly, urea produces the lowest transportation costs per unit of nitrogen feed. Urea in the soil is hydrolyzed and converted into ammonia and carbon dioxide. Ammonia resulting from this process is oxidized to nitrate by the bacteria in the soil, and as a result, it can be absorbed by the plant.
Urea is also used in many cases in the multi-component formulation of solid fertilizers. Urea is usually spread between 40 and 300 kg per hectare in agricultural lands, urea can be added dry to the soil, or it can be used as a solution through irrigation water. The process of dissolving urea in water is an endometrial process that causes the temperature of the solution to drop when urea is dissolved.
Urea is an important raw material for the production of many chemical compounds, such as:
All kinds of plastics, especially urea formaldehyde resins.
Types of adhesives, such as urea formaldehyde and urea melamine formaldehyde, which are used in the production of plywood for water.
Potassium cyanate, as a raw material for some industries.
Urea nitrate, a type of explosive.
Urea is used in SNCR and SCR reactions in order to reduce NO pollutants, which are present in combustion gases. For example, gases coming out of power plants or diesel engines. In the case of diesel engines, this process is called diesel particulate filter regeneration. In the case of Blue Tec systems, for example, water-soluble urea is injected into the car’s exhaust system. Ammonia obtained from urea decomposition process reacts with output nitrogen oxide and is converted into nitrogen and water by a catalytic converter.
Ammonia with the chemical formula NH3 is the most important hydrogenated compound of nitrogen, which is obtained in nature from the decomposition of nitrogen-containing organic substances such as urine urea. Ammonia is a colorless gas with an extremely pungent taste and an acute and unpleasant taste that is tear-inducing and suffocating. Ammonia gas is lighter than air and easily turns into liquid. Ammonia is very soluble in water and freezes at minus 77.7 degrees Celsius and boils at minus 33.34 degrees Celsius.
The specific gravity of ammonia saturated solution is 0.88 grams per cubic centimeter. Ammonia gas can be ignited and its ignition range is 16-25% by volume of ammonia gas in the air. The presence of petroleum and other flammable substances increases the risk of fire. Ammonia gas decomposes in the heat of 400 degrees and produces hydrogen and nitrogen. Among the uses of ammonia, we can mention the use in the preparation of chemical fertilizers (nitrate and phosphate fertilizers), the preparation of nitric acid, refrigerant gas in cooling devices and the production of explosives.
- Production process:
Ammonia production – based on the direct synthesis of ammonia through hydrogen (resulting from steam reforming and methane natural gas) and nitrogen (resulting from air) in a reactor that converts them into ammonia.
Urea production – using ammonia and carbonic anhydride (the result of the ammonia production process) and their combination and the production of carbamate, which is then converted into molten urea in the urea production reactor. Next, urea granulation is done in the relevant process and the product is sent to the warehouse.