Catalogue of synthetic ammonia production processes, specifications of synthetic ammonia products an

Ammonia is one of the important inorganic chemical products and occupies an important position in the national economy. In addition to liquid ammonia, which can be used directly as fertilizer, nitrogen fertilizers used in agriculture, such as urea, ammonium nitrate, ammonium phosphate, ammonium chloride and various nitrogen-containing compound fertilizers, are all made of ammonia. Synthetic ammonia is one of the bulk chemical products, the world's annual production of synthetic ammonia has reached more than 100 million tons, of which about 80% of ammonia is used to produce chemical fertilizers, 20% as raw materials for other chemical products.

There are two main processes for the synthesis of ammonia.

1.Thermocatalytic ammonia synthesis.

Industrial ammonia synthesis is mainly controlled by the Haber-Bosch process. Ammonia is produced in a 3:1 ratio of hydrogen and nitrogen mixed in the presence of an iron-based catalyst in the temperature and pressure ranges of 723-873 K and 10-25 MPa, respectively.

The Haber-Bosch process has a conversion of about 15-25% to ammonia per run, and is ** by unreacted gases, resulting in a total conversion of 97%. The RU-based catalyst is the second generation catalyst, which can react at 300E450 and 4-15 MPa. Depending on the catalyst, the conditions are also different.

2.Electrochemical ammonia synthesis.

There are four categories based on the type of electrolyte used.

1) liquid electrolytes working at room temperature;

2) molten salt electrolytes operating at 573-773 K;

3) a composite electrolyte consisting of a solid electrolyte mixed with a low melting point salt operating at 573-973 K;

4) Solid electrolyte, operating from room temperature to a maximum of 1073 K.

It's kind of a help to tidy up more in your own field. Helping to improve China's academic environment. (denblidue)

The first step is the preparation of the feed gas. To produce ammonia by synthetic method, it is first necessary to prepare feed gas containing hydrogen and nitrogen. It can be made by mixing hydrogen and nitrogen separately, or it can be produced at the same time.

The second step is the purification of the raw gas. The hydrogen and nitrogen raw gas produced contains impurities such as sulfur compounds, carbon monoxide, and carbon dioxide. These impurities can not only corrode equipment, but also poison ammonia synthesis catalysts.

Therefore, before the hydrogen and nitrogen raw gas is sent to the synthesis tower, it must be purified to remove various impurities and obtain a pure hydrogen and nitrogen mixture.

The third step is the compression of the feed gas and the synthesis of ammonia. The pure hydrogen-nitrogen mixture is compressed to high pressure and synthesized into ammonia at high temperatures and in the presence of a catalyst.

The raw materials for the production of synthetic ammonia are mainly coke, coal, natural gas, heavy oil, light oil and other fuels, as well as water vapor and air; The main process of producing synthetic ammonia is generally shown in the figure below.

Raw materials Preparation of raw gas Desulfurization Transformation of carbon monoxide Decarburization Removal of a small amount of carbon monoxide and carbon dioxide Synthesis of compressed ammonia Ammonia products.

Ammonia synthesis is an important chemical that is widely used in the manufacture of fertilizers and other chemicals. This article will introduce the process flow diagram of ammonia synthesis and its process.

First of all, the production of synthetic ammonia requires the use of large amounts of natural gas and air. In this process, natural gas and air are mixed together and then changed through a series of oxygen and ant-stateization and reduction reactions. The purpose of these reactions is to combine nitrogen oxide with hydrogen to form ammonia and to expel some of the unreacted nitrogen from the system.

At this point, we have a gas containing a high concentration of ammonia.

Next, the gas must be dehydrated to remove the moisture from it. This can be done by passing the gas through one adsorbent. As the gas flows through the adsorbent, the moisture is absorbed by the material on it, allowing the moisture in the gas to be removed.

Finally, the gas used to synthesize ammonia needs to be compressed into a liquid, which can be done by a device called a throttle valve. The role of the throttle valve is to introduce the gas into a contractile and then pressurize it. The pressurized gas becomes a liquid that can be used in storage and transportation.

In conclusion, the process of ammonia synthesis involves many steps. However, it is only by understanding these steps that we can successfully manufacture high-quality fertilizers and other chemicals.

1. Pressure. Affected by power materials and equipment, China's synthetic ammonia plants generally use 20MPa and 50MPa.

2. Temperature. From the perspective of ideal conditions, the synthesis of ammonia is advantageous at a lower temperature, but the temperature is too low, and the reaction rate will be very small, so in the actual production of filial piety, 500 °C is generally selected.

3. Catalyst.

The iron catalyst is the most active at 500 °C, which is also the reason why the synthetic ammonia is selected at 500 °C.

1) Feed gas preparation: First, raw materials such as coal and natural gas are made into crude feed gas containing hydrogen and nitrogen. For solid raw coal and coke, syngas is usually produced by gasification; Syngas can be obtained by non-catalytic partial oxidation of residual oil; For gaseous hydrocarbons and naphtha, syngas is produced by two-stage steam reforming method in industry.

2) Purification: Purify crude raw gas to remove impurities other than hydrogen and nitrogen, mainly including transformation process, desulfurization and decarburization process and gas refining process.

3) Finally, the pure hydrogen and nitrogen mixture is compressed to high pressure, and ammonia is synthesized under the action of a catalyst. Ammonia synthesis is the process of providing liquid ammonia products and is a core part of the entire ammonia production process. The ammonia synthesis reaction is carried out under the conditions of higher pressure and the presence of catalyst, because the ammonia content in the gas after the reaction is not high, and only 100 filial piety is generally returned, so the process of unreacted hydrogen and nitrogen circulation is adopted.

The work mainly includes: (1) using pressurized conveying machinery to send hydrocarbon-containing raw materials and air or water vapor into the gas furnace; (2) Operate the gas furnace to adjust the process parameters such as temperature, pressure, flow rate and ratio to make raw gas; (3) Operate the production equipment for removing sulfide, carbon monoxide, carbon dioxide, etc., and purify the raw gas into 1:3 nitrogen-hydrogen mixture; (4) Operate a multi-stage compressor to pressurize the nitrogen-hydrogen mixed gas into the ammonia synthesis tower; (5) Adjust the process parameters such as pressure, temperature and space velocity of the ammonia synthesis tower, and synthesize part of the nitrogen-hydrogen mixed gas into ammonia in the presence of a catalyst; (6) Monitor the condensation or absorption device to condense the ammonia in the ammonia-containing nitrogen-hydrogen mixture into liquid ammonia or absorb it into ammonia water; (7) Operate the circulating compressor to pressurize the nitrogen-hydrogen mixed gas that separates the ammonia and send it to the synthesis tower to circulate ammonia production with the new nitrogen-hydrogen mixture.

The following types of work are classified as occupations:

Synthetic ammonia chief control engineer (16-034), water gas engineer (16-035), oil and gas chemical industry (16-036), synthetic ammonia conversion engineer (16-038), synthetic ammonia purification worker (16-039), synthetic ammonia gas compression worker (16-040), ammonia synthesis worker (16-041).

The chemical equation for industrial ammonia synthesis is the Haber-Bosch process: N2(G)+3H2(G) 2NH3(G).

In this equation, N2 represents nitrogen, H2 represents hydrogen, and NH3 represents ammonia. According to the equation, 1mol of nitrogen and 3mol of hydrogen react to produce 2mol of ammonia. This equation describes the synthesis reaction of nitrogen and hydrogen to produce ammonia.

The reaction is carried out at high temperatures (about 400-500°C) and high pressures (about 150-250 atmospheres) and usually requires the use of catalysts such as iron or iron-molybdenum to accelerate the reaction rate.

Industrial ammonia synthesis is an important chemical process used in the production of fertilizers and other chemicals. The discovery and application of this process has played an important role in solving the problem of nitrogen fertilizer in the agricultural field.

Conditions for industrial ammonia synthesis

1. Temperature: The industrial synthetic ammonia reaction needs to be carried out under high temperature conditions, usually between 400-500 °C. Higher temperatures can increase the reaction rate, but also increase energy consumption and the formation of reaction by-products.

2. Pressure: The reaction of industrial synthetic ammonia needs to be carried out under high pressure conditions, usually between 150-250 atmospheres. High pressure can increase the chance of nitrogen and hydrogen slag contact and promote the reaction.

3. Catalyst: The industrial ammonia synthesis reaction requires the use of catalysts to accelerate the reaction rate. Commonly used catalysts include iron (Fe) or iron-molybdenum (Fe-Mo) catalysts. These catalysts can reduce the activation energy of the reaction and increase the reactivity of nitrogen and hydrogen.

4. Gas ratio: The gas ratio of reactants is also an important condition affecting the reaction of industrial ammonia synthesis. In general, the molar ratio of the reactants is n2:h2=1:3.

5. Reactor design: In order to realize the industrial ammonia synthesis reaction under high temperature and high pressure conditions, it is necessary to design and use appropriate reactors. Common reactor designs include tubular reactors, fixed-bed reactors, or fluidized bed reactors.