Ammonia production method of ammonia, method of preparing ammonia

Industrial ammonia is produced by the Haber method by direct combination of N2 and H2 under high temperature and high pressure and in the presence of a catalyst

Ammonia is produced industrially.

N2+3H2==High temperature and high pressure catalyst===2NH3 (reversible reaction).

RH = The vast majority of industrial ammonia production is produced by the synthesis of nitrogen and hydrogen under high pressure, high temperature and in the presence of catalysts. Nitrogen is mainly found in air; Hydrogen is mainly used in syngas containing hydrogen and carbon monoxide (pure hydrogen is also used in the electrolysis of water). The mixture of nitrogen and hydrogen is the raw gas for ammonia synthesis.

The feed gas from the fuel chemical industry contains sulfur compounds and carbon oxides, which are toxic substances to the catalyst for ammonia synthesis and are purified before ammonia synthesis.

1. Haber method of ammonia: high temperature and high pressure N2 (G) + 3H2 (G) *****===2NH3 (G) (reversible reaction) rh =

Catalyst. 2. Ammonia production from natural gas: natural gas is first desulfurized, then through secondary conversion, and then through carbon monoxide transformation, carbon dioxide removal and other processes respectively, to obtain nitrogen-hydrogen mixture, which still contains carbon monoxide and carbon dioxide about volume), after methanation removal, pure gas with a molar ratio of hydrogen to nitrogen is 3, which is compressed by the compressor and enters the ammonia synthesis circuit to obtain product ammonia.

The process of producing ammonia from naphtha is similar to this process.

3. Ammonia production from heavy oil: heavy oil includes the residue obtained from various deep processing, and the synthetic ammonia raw gas can be prepared by partial oxidation method, and the production process is simpler than that of natural gas steam reforming, but an air separation device is required. The oxygen produced by the air separation unit is used for heavy oil and gasification, and nitrogen is used as a raw material for ammonia synthesis.

4. Coal (coke) to ammonia: direct coal gasification (see coal gasification) has a variety of methods such as atmospheric fixed-bed intermittent gasification, pressurized oxygen and steam continuous gasification. For example, in the early Haberbusch process of ammonia synthesis, air and steam were used as gasifiers, and coke was reacted with coke at atmospheric pressure and high temperature to produce gas containing (CO+H2) N2 molar ratio, which was called semi-aqueous gas.

After the semi-water gas is washed and dusted, the gas cabinet is degassed, and after the carbon monoxide transformation is transformed and compressed to a certain pressure, the carbon dioxide is removed by pressurized water, and then further compressed with a compressor and washed with cupra ammonia solution to remove a small amount of carbon monoxide and carbon dioxide, and then sent to synthetic ammonia. In the laboratory, ammonia is often prepared by the reaction of ammonium salt with alkali or by the characteristics of nitride easy hydrolysis: 2NH4Cl (solid) + Ca(OH)2 (solid) ===2NH3 + CACl2 + 2H2O

li3n + 3h2o === 3lioh + nh3↑

A method for rapid production of ammonia in the laboratory.

Ammonia gas is prepared by adding solid NaOH with concentrated ammonia.

Ammonium salts are commonly used to react with alkali or to be prepared by using the characteristics of nitride that are easily hydrolyzed.

Chemical Reaction Equation:

2NH Cl (solid state) + Ca(OH) (solid state) ===2NH +CaCl +2H O

Li N + 3H O === 3LiOH + NH ammonia can also be prepared by adding concentrated ammonia water to solid NaOH.

nh₄⁺+oh⁻=nh₃·h₂o

Solid ammonium salt preparation.

Reaction principle: 2NH4Cl+Ca(OH)2

cacl2+2nh3↑+2h2o

Reaction device: solid + solid heating gas production device. Including test tubes, alcohol lamps, iron stands (with iron clips), etc.

Purification device (can be omitted): dried with soda lime.

Collection device: downward exhaust air method, the full method is to use moistened red litmus test paper placed at the mouth of the test tube, the test paper turns blue; Or put a glass rod dipped in concentrated hydrochloric acid at the mouth of the test tube, and white smoke will be generated.

1.Industrial method: industrial ammonia is made by direct combination of N2 and H2 under high temperature and high pressure and the presence of a catalyst by the Haber method

Ammonia is produced industrially.

High temperature and high pressure. N2 (g) + 3H2 (G) ***** ===2NH3 (G) (reversible reaction).

Catalyst rh =

2.Laboratory Preparation:

In the laboratory, ammonia is often prepared by the reaction of ammonium salts with alkali or by using the characteristics of nitride that are easily hydrolyzed

2NH4Cl (solid state) + Ca(OH)2 (solid state) ===2NH3 + CaCl2 + 2H2O

li3n + 3h2o === lioh + nh3↑

1) It is not possible to use NH4NO3 to react with Ca(OH)2 to produce ammonia.

Because NH4NO3 is an oxidizing ammonium salt, NH3 and HNO3 are generated at low temperature when heated, and as the temperature rises, the strong oxidation of nitric acid plays a role in making the generated ammonia further oxidized to produce nitrogen and nitrogen oxides, so NH4NO3 cannot be used to react with Ca(OH)2 to produce ammonia.

2) Laboratory-made NH3 cannot replace Ca(OH)2 with NaOH and KOH

Because NaOH and KOH are strong bases, they are hygroscopic (deliquescent) and easy to agglomerate, and are not easy to mix with ammonium salts for full contact reaction. In addition, KOH and NAOH have strong corrosiveness, and in the case of heating, they have a corrosive effect on glass instruments, so NAOH and KOH are not used instead of CA(OH)2 to make NH3.

3) Why do you need to block cotton when collecting ammonia with a test tube.

Because NH3 particles are small in diameter and prone to convection with air, the purpose of plugging cotton is to prevent NH3 from convection with air and ensure the purity of collection.

4) Why do we use alkali lime instead of concentrated H2SO4 and solid CaCl2 for the water vapor removal of NH3 prepared in the laboratory

Because concentrated H2SO4 reacts with NH3 to form (NH4)2SO4

NH3 reacts with CaCl2 to form CaCl2·8NH3 (calcium chloride with octaammonia).

cacl2+8nh3==cacl2·8nh3

5) A method for rapidly preparing ammonia in the laboratory.

Add solid NAOH (or heat concentrated ammonia) with concentrated ammonia

1. Industrial manufacturing method:

Industrial ammonia is produced by the Haber method by direct combination of N2 and H2 under high temperature and high pressure and in the presence of a catalyst

n +3h 2nh , rh = kj mol (reaction conditions are high temperature, high pressure, catalyst).

Generally, iron catalyst is used as a catalyst, with a pressure of 20-50 MPa and a temperature of about 450.

2. Experimental preparation:

In the laboratory, ammonia is often prepared by the reaction of ammonium salts with alkali or by using the characteristics of nitride that are easily hydrolyzed

Li N + 3H O = 3LiOH + NH Rapid preparation of ammonia in the laboratory: ammonia is prepared by reacting concentrated ammonia water with solid NaOH.

Ammonia Inspection:

1) Method 1:

Tested with moistened red litmus paper, the test strip turned blue to prove the presence of ammonia.

2) Method 2:

Approaching with a glass rod dipped in concentrated hydrochloric acid produces white smoke, which proves the presence of ammonia.

(white solid).

3) Method 3:

Ammonia detectors can quantitatively measure the concentration of ammonia in the air.

The above content refers to the encyclopedia of ammonia.

Industrial Method.

Industrial ammonia is produced by the Haber method by direct combination of N2 and H2 under high temperature and high pressure and in the presence of a catalyst

N2+3H2 2NH3 RH = kJ mol (reaction conditions are high temperature, high pressure, catalyst).

Generally, iron catalyst is used as a catalyst, with a pressure of 20-50 MPa and a temperature of about 450.

Experimental preparation.

In the laboratory, ammonium salts are commonly used in ammonia.

Prepared by interacting with alkali or using the properties of nitride that are easily hydrolyzed:

li3n + 3h2o = 3lioh + nh3↑

The method of rapid preparation of ammonia in the laboratory: with concentrated ammonia.

and solid NaOH reaction to prepare ammonia;

Fountain Experiment. At room temperature and pressure, 700 volumes of ammonia can be dissolved in one volume of water.

Dry the round-bottom flask.

Fill with ammonia and plug the bottle tightly with a stopper with a glass tube and a dropper (pre-sucked water in the dropper). Immediately invert the flask so that the glass tube is inserted into the beaker containing the water.

(A small amount of phenolphthalein is added to the water beforehand.)

test solution), after the experimental device is installed.

Open the clamp of the rubber tube and squeeze the rubber tip of the dropper to let a small amount of water into the flask and observe the phenomenon. The basic principle of the experiment is to make a large pressure difference between the inside and outside of the flask in a short period of time, using atmospheric pressure.

The liquid from the beaker under the flask is pressed into the flask, creating a fountain at the mouth of the needle-nose catheter.

Summary.

1. Ventilation method: open the window for ventilation, and turn on the electric fan to accelerate the indoor and outdoor air exchange, and can effectively remove a large amount of indoor ammonia.

2. Activated carbon method: Activated carbon is placed indoors, and activated carbon is used as a natural air purifier with the natural characteristics of easy purification and pollution-free. Activated carbon can adsorb formaldehyde, toluene, xylene and ammonia in the air, which are the main culprits of indoor air pollution, so as to achieve the purpose of anti-corrosion, moisture-proof, deodorant, mildew-proof, sterilization and disinfection.

How to effectively neutralize ammonia in a simple way?

1. Ventilation method: open the window for ventilation, and turn on the electric fan to accelerate the indoor and outdoor air exchange, and can effectively remove a large amount of indoor ammonia. 2. Activated carbon method:

Activated carbon is placed indoors, and as a natural air purifier, activated carbon has the natural characteristics of easy purification and no pollution. Activated carbon can adsorb formaldehyde, toluene, xylene and ammonia in the air, which are the main culprits of indoor air pollution, so as to achieve the purpose of anti-corrosion, moisture-proof, deodorant, mildew-proof, sterilization and disinfection.

How to quickly remove the odor in chicken manure.

Rapid fermentation of chicken manure removes ammonia from chicken manure.

If the chicken coop is small, ventilate and shovel the chicken manure frequently, which can remove the smell of ammonia, but the problem is that the labor intensity is too great.

In general, nitrogen and hydrogen are used to synthesize ammonia at high temperature and high pressure, and the reaction formula is:

N2(g)+3H2(G) 2NH3(G), Rh = kJ mol (reaction conditions are high temperature, high pressure, catalyst).

However, the laboratory usually uses ammonium salt to react with alkali or uses the characteristics of nitride to carry water to carry bright solution to prepare the formula as follows

2nh4cl+ca(oh)2==2nh3+cacl2+h2oli3n+2h2o==3lioh+nh3

It can also be prepared with concentrated ammonia and solid sodium hydroxide, ammonia and sodium hydroxide itself will not react, but sodium hydroxide dissolved in ammonia will release or code out a large amount of heat, so that ammonia decomposition

The first is ammonia gas prepared by heating ammonium salt and alkali, (most commonly used) (solid-solid heating) The chemical equation is: 2NH4Cl (solid) + Ca(OH)2 (solid) ==2NH3 + CACl2 + 2H2O2

Second, concentrated ammonia water is used to produce ammonia fiber friendly gas under heating conditions, <>NH3·H2O = NH3 + H2O, and the condition is heating. acres are made vertically.

Thirdly, ammonia is prepared by adding solid alkali rapidly equilibratory substances (such as CaO, NaOH) to concentrated ammonia water, C(OH-) increases, the equilibrium moves to the left, and the reaction is exothermic, which promotes the decomposition of NH3·H2O into NH3 + H2O.

nh3+h2o⇌ nh3·h2o⇌nh4+ +oh-<>

( ) The main use of ammonia: mainly for the manufacture of urea, ammonium phosphate, melamine, ammonium bicarbonate, ammonium chloride, ammonium sulfate, ammonium nitrate, nitric acid, acrylonitrile and other inorganic and organic chemical products and raw materials for refrigeration, plastics, metallurgy, medicine, national defense and other industries. So what is the industrial production method of ammonia?

With the development of large-scale, the ammonia synthesis circle has become one of the main units to reduce the energy consumption of ammonia synthesis. There are three representative designs of modern large-scale ammonia synthesis plants:

1.Brown's Three Towers and Three Waste Pots Ammonia Synthesis Circle: The Brown Three Towers and Three Waste Pots Ammonia Synthesis Circle consists of 3 synthesis towers and 3 waste pots.

There is a catalyst basket in the tower, and the gas flows upwards from the bottom through the gap between the shell and the basket body, and then flows axially through the catalyst bed from top to bottom. The loading capacity of the catalyst in the third tower is more than that in the second tower, and the final export ammonia content can be increased to more than 21%, which reduces the amount of circulating gas and saves the circulating compression work. The control system of the synthetic tower is very simple, and each tower is equipped with a bypass to adjust the temperature of the gas entering the tower with a valve.

Due to the limitation of the equilibrium of the ammonia synthesis reaction, the catalyst temperature is determined, and there is no need to adjust the reaction temperature of the catalyst bed.

2.Wood Two Towers, Three Beds, Two Waste Pots, Ammonia Synthesis Circle: Wood Two Towers, Three Beds, Two Waste Pots, Ammonia Synthesis Circles, Two Smaller Synthesis Towers, Three Catalyst Beds, and One Waste Pot Behind Each of the Two Towers.

This structure makes the reaction temperature distribution very close to the optimal reaction temperature, the circulation volume and pressure drop of the gas are small, the investment and energy consumption are saved, and the by-product high-pressure steam is more.

3.Topsoe 2-Tower, 3-Bed, 2-Waste Pot Ammonia Synthesis Circle: The Topsoe S-250 system consists of an S-200 synthesis tower and an S-50 synthesis tower without lower heat exchange.

It also includes: (1) waste heat from waste pot and boiler feedwater heat exchanger; (2) Synthesis tower inlet and outlet gas heat exchanger, water cooler, ammonia cooler and cold exchanger, brigade ammonia separator and fresh gas ammonia cooler, etc. The synthesis tower is a radial flow catalyst bed, using a small catalyst with a pressure drop of .

The syngas from the S-200 tower is heated by the waste heat boiler and the appropriate temperature into the S-50 tower is ensured to improve the single-pass synthesis rate.

Other methods. Ammonia from natural gas. Natural gas is first desulfurized, then through secondary conversion, and then through carbon monoxide shift, carbon dioxide removal and other processes to obtain nitrogen-hydrogen mixture, which still contains carbon monoxide and carbon dioxide about volume), after methanation removal, pure gas with a molar ratio of hydrogen to nitrogen is 3, which is compressed by a compressor and enters the ammonia synthesis circuit to obtain product ammonia.

The process of producing ammonia from naphtha is similar to this process.

Ammonia production from heavy oil. Heavy oil includes residue oil obtained from various deep processing, and synthetic ammonia raw gas can be prepared by partial oxidation method, and the production process is simpler than that of natural gas vapor reforming, but an air separation device is required. The oxygen produced by the air separation unit is used for heavy oil and gasification, nitrogen is used as a raw material for ammonia synthesis, and liquid nitrogen is also used as a detergent for the removal of carbon monoxide, methane and argon.

Coal (coke) to ammonia. With the development of petrochemical industry and natural gas chemical industry, the method of producing ammonia from coal (coke) as raw material has been rarely used in the world.