The invention relates to a safe preparation process of powder metallurgy reducing atmosphere

One, foreword

Powder metallurgy enterprises often need to use hydrogen as a reducing process gas when sintering the workpiece. However, the traditional method of producing hydrogen by ammonia decomposition is more and more unable to meet the increasing requirements of the state and enterprises for safe production because of the great safety risks in the process.In order to ensure safe production, enterprises and safety regulatory departments have taken how to safely manufacture and use hydrogen reduction process gas as the focus of investigation and improvement, and in some areas have clearly prohibited enterprises to use ammonia decomposition equipment.

According to the professional characteristics of powder metallurgy enterprises, our company has developed a new type of methanol low temperature cracking hydrogen production equipment, specially for powder metallurgy enterprises to provide safe and reliable hydrogen production equipment, so that enterprises can more safely obtain hydrogen reduction process gas, its working principle and characteristics are introduced as follows.

Second, a brief introduction to the working principle of the new methanol pyrolysis for hydrogen production

1. The reaction equation of conventional ammonia decomposition to produce hydrogen is as follows:

2NH3=3H2+N2 (decomposition temperature 780 ~ 850℃)

2. Different from the traditional process of hydrogen production from ammonia decomposition, the new hydrogen production process uses methanol cracking to produce hydrogen. Under certain temperature and pressure conditions, methanol cracking reaction and conversion reaction of carbon monoxide occur through the action of catalyst, which is a gas-solid catalytic reaction.

CH3OH=2H2+CO (cracking temperature 240 ~ 280℃)

H2 generated by cracking reaction and CO are reductive gases, CO in the furnace can play a role in reducing and protecting the workpiece, in front of the furnace and the oxygen in the air to react to generate CO2 diffusion into the atmosphere, after years of use in dozens of manufacturers proved that it will not cause any harm to the operator.

Three, new methanol cracking of hydrogen production process security features                                                                                                                                                                                                                                                1. The safety characteristics of raw materials used in hydrogen production are different:

Methanol is a liquid at room temperature, and it is not easy to volatilize and diffuse rapidly in the air, while ammonia is a toxic, flammable and dangerous gas. Liquid ammonia is easy to volatilize and diffuse in the air, and the consequences of leakage are unimaginable, so enterprises need to handle special procedures for the use of liquid ammonia.Methanol is not corrosive and is not afraid of contact with human skin. As long as it is not drunk by mistake, it will not cause harm to people. However, ammonia is corrosive and does great harm to people’s skin and eyes, so it is safer to use methanol.

2. Raw materials used in hydrogen production are stored without pressure vessels

Liquid ammonia needs to be stored in special pressure vessels, which requires strict management of filing, verification and maintenance of the pressure vessels storing liquid ammonia according to safety management regulations.Methanol storage only needs room temperature and atmospheric pressure container, no special pressure container is needed for storage.

3. The danger of flammable gas leakage is avoided in the process of hydrogen production

The pyrolysis temperature of methanol is low, and methanol can be cracked only at 240 ~ 280℃, which is much lower than the decomposition temperature for hydrogen production from ammonia decomposition (higher than 800℃). In this way, the heating element and reactor will not be burned out, and the hydrogen produced will not be burned through the tank, resulting in the escape of the prepared hydrogen and ignition or even explosion.The danger of flammable gas leakage is completely avoided.

4, the use of methanol low temperature cracking equipment operation cost is lower because methanol is low temperature cracking (240~280℃), the reaction temperature is only 1/3 of the ammonia decomposition, so the operation cost is less than half of the ammonia decomposition equipment, so it is also a more energy saving equipment.

5. It is easier to purchase methanol

Methanol can be easily procured anywhere at the local chemical market.

Four, conclusion

From the above analysis, it can be seen that the new methanol cracking hydrogen production equipment has the following advantages:

Methanol cracking temperature is low, so the service life of the equipment is longer, more safe, and the operating cost is lower. Methanol is easier to purchase and store, at the same time, methanol is not corrosive, not easy to volatilize and diffuse, unlike liquid ammonia, which needs special containers for storage. Once it is leaked, it will be very dangerous.

New methanol cracking hydrogen production equipment of our company in shandong, jiangsu, zhejiang and other multiple areas of dozens of powder metallurgy enterprise to use, not only by completely satisfy the reducing atmosphere of hydrogen technology indicators, the production cost is reduced, the new equipment and process method no new environmental problems, especially in eliminating enterprise security hidden danger is well,We will help enterprises improve their safety management.Safety production management is the top priority of the enterprise. We believe that through the participation of more and more personnel, we will put forward more safe preparation and use of hydrogen reduction process gas schemes for powder metallurgy product factories, so as to ensure that the enterprise can make due contributions to the society under the premise of safe production.


Post time: Jun-15-2021