Urea production and manufacturing process, reactions and uses

Urea is a very important industrial production which is much used in agricultural field as a fertilizer because urea contains high percentage of nitrogen. Urea dissolves very well in water. Urea is called also as carbamide, which is an organic compound with chemical formula of CO(NH2)2. Urea is a white solid.

Urea molecular formula - CO(NH2)2

Urea is an amide compound and has two -NH2 groups connecting to the carbonyl group.

Urea molecule structure

urea molecular structure

In this tutorial, we first discuss urea manufacturing process, raw materials, reactions and uses of urea. Then study some useful reactions of urea and urea manufacturing plants in the world.

Manufacturing process of urea

Raw Materials of Urea manufacturing

Ammonia is manufactured by haber process in the industry. CO2 is prepared by decomposition of limestone (CaCO3). When CaCO3 is heated, it decomposes to CaO and CO2.

Urea manufacturing process

Liquid ammonia is allowed to react with liquid carbon dioxide in a reactor at high temperature and pressure. The conditions employed are 130-1500C and a pressure of 35 atm. urea is formed in two-step reactions.

urea production process

First step,

Ammonia and carbon dioxide reaction

Ammonia and carbon dioxide react together and give ammonium carbamate (NH2COONH4)

Ammonia and carbon dioxide react together and give ammonium carbamate

Fast, Exothermic , Go to completeness at industrial situations.

Second Reaction,

Ammonium carbamate to urea reaction

ammonium carbamate gives urea

Slow, Endothermic , does not go to completeness.

Manufactured urea contains unreacted ammonia and carbon dioxide and ammonium carbamate. Ammonium carbamate is removed by reducing the pressure (Le Chatelier's Principle). When heating, ammonia and carbon dioxide is separated. The advantage of this process is ammonia and carbon dioxide can be recycled back to the process.

Urea is obtained as a solution, but that solution is concentrated to give 99.6% molten urea, and granulated for use for fertilizer.

Industrial uses of urea

  • Good fertilizer due to high percentage of Nitrogen
  • To produce Urea-Formaldehyde polymer.

Why urea is better than other fertilizers? (Advantages)

  • Highest nitrogen content than any other nitrogenous fertilizer in the market.
  • Low production cost
  • Can be used for any type of crop
  • No harm to the soil

Reactions of urea

Urea and NaOH reaction

Ammonia and sodium carbonate are given as products by the reaction of urea and NaOH.

Urea and NaOH reaction

Urea and formaldehyde reaction

Urea and formaldehyde (HCOH) react in acidic medium to give urea-formaldehyde polymer. urea-formaldehyde polymer is very firm and used to manufacture wood adhesives.

Urea and formaldehyde reaction

Urea and nitrous acid reaction

CO2, N2, and H2O are the products of reaction of urea and nitrous acid (HNO2).

Urea and nitrous acid reaction

Urea and carboxylic acid reaction

An amide, carbon dioxide, and ammonia are given as the products after reacting urea with carboxylic acids.

Urea and carboxylic acid reaction

Environmental pollution due to urea manufacturing

Urea production may cause several environmental pollution problems. These problems occur due to poor maintenance of the plant, leakages of toxic materials and more.

  • Ammonia is a very toxic gas. Ammonia gas can be leaked from urea manufacturing plant to air or water, if plant is not maintained properly. It can cause health problems for people and animals. Ammonia can be oxidized to oxides of nitrogen.
  • If coral is used to get limestone, it is caused to coastal erosion.

Urea Production in United States of America

KOCH Fertilizers is a leading urea manufacturing company in USA. They have other fertilizers too. They produce 13 million tons of different fertilizer products annually.

Questions of urea production

Urea production countries

India is the top country of urea production. China, Indonesia, Russia, Qatar are the next other countries of urea production.

What are the toxic materials used in urea production?

Ammonia is the most toxic material used in the urea manufacturing. Carbon dioxide is not much dangerous when it compares with ammonia. But it causes to increase the temperature of the environment.

Major engineering problems during the manufacture of urea

Urea manufacturing second reaction is not going to completeness. So to get maximum output, we have to maintain the temperature and pressure properly. Otherwise prouction quality decreases due to low production.

By which reaction urea is produced?

Urea cannot be produced by a single reaction. It requires two steps reactions to get the product. First, ammonium carbamate is produced and next ammonium carbomate decomposes to urea and water.

Is urea making process is possible to do in homes?

It is not possible to manufacture urea in home as a chemical because it requires well designed plant to work. Also it requires very high temperature which is impossible to get in houses. In addition, the safety should be considered in higher place due to hazardous chemicals.

What is the significance in ammonia, water in urea production?

Every indistrial plant, different equipments are worked. Sometimes those machines generate lot of heat. So we need to remove that heat to protect those machines by higher temperature. So we use water as a coolant for this purpose.

Why urea is considered as a very good fertilizer?

Nitrogen content of urea is very high. Usually it may around 46%. And urea's water solubility is high. Due to that reason absorbing urea to plants is easy.

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