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

In powder metallurgy enterprises, hydrogen is often used as the reducing process gas when sintering the workpiece. However, the traditional method of hydrogen production by decomposition of ammonia, which is used at present, is increasingly unable to meet the increasing requirements of the country and enterprises for safety production due to the large safety risks of the process method. In order to ensure safe production, both enterprises and safety regulatory departments regard how to safely manufacture and use hydrogen reduction process gas as the focus of investigation and improvement, and in some areas, enterprises have been explicitly prohibited from using 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.

Introduction to the working principle of new methanol cracking hydrogen production

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

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

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

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

H2 and CO generated by cracking reaction are reducing gases, CO in the furnace can play a role in reducing and protecting the workpiece, in front of the oven and the oxygen reaction in the air 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’s body.

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

Methanol is a liquid state at room temperature, which is not easy to rapidly volatilize and diffuse in the air, while ammonia is a toxic and flammable dangerous gas. Liquid ammonia is easy to volatilize and diffuse in the air, and the consequences of leakage are unimaginable. Therefore, enterprises need to go through special procedures for the use of liquid ammonia before it can be used. Methanol is not corrosive and is not afraid of contact with human skin. As long as it is not consumed by mistake, it will not cause harm to people. While ammonia is corrosive and is very harmful to people’s skin and eyes, so it is safer to use methanol.

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

Liquid ammonia needs special pressure vessels for storage, which requires strict management such as filing, verification and maintenance of the pressure vessels storing liquid ammonia according to safety management regulations. Methanol storage only needs room temperature and pressure vessels, not special pressure vessels.

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

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

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

5. Methanol procurement is easier

Methanol can be easily purchased anywhere in the local chemical market.

Four, conclusion

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

The temperature of methanol pyrolysis is low, so the service life of the equipment is longer, safer, and the operation cost is lower. Methanol is easier to purchase and store. Meanwhile, methanol is not corrosive and not volatile and diffused.

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, Help enterprises improve the level of safety management. Safety production management is the top priority of the enterprise. We believe that with the participation of more and more personnel, we will put forward more schemes for powder metallurgy product factories to make and use hydrogen reduction process gas safely, so as to ensure that enterprises can make due contributions to the society under the premise of safe production.


Post time: Aug-24-2021