Selection criteria for anti-corrosion materials (e. g. Hastelloy) for propylene oxide production equipment?

Criteria for selection of anti-corrosion materials for propylene oxide production equipment

Propylene is an important organic chemical raw material, which is widely used in the manufacture of epoxy resins, coatings, cellulose derivatives and other fields. In the production process of propylene oxide, due to the particularity of process conditions (such as high temperature, high pressure, strong corrosive medium, etc.), the production equipment is susceptible to corrosion, which affects the production efficiency and equipment life. Therefore, the selection of suitable anti-corrosion materials is very important for the stable operation of propylene oxide production equipment. Based on the selection criteria of materials, this paper analyzes the selection basis of anti-corrosion materials for propylene oxide production equipment, and focuses on the application of corrosion-resistant materials such as Hastelloy (Hastelloy).

1. Propylene oxide production equipment corrosion environment analysis

The propylene oxide production process usually involves a variety of corrosive media, such as hydrochloric acid, sulfuric acid, nitric acid, sodium hydroxide and other strong acids and strong alkaline substances, as well as organic solvents and wet chlorinated gases. The production process may also produce high temperature, high pressure and strong oxidizing environment. These factors work together to put forward extremely high requirements on the materials of production equipment.

In such a corrosive environment, ordinary carbon steel, low alloy steel and other materials are prone to pitting corrosion, intergranular corrosion or stress corrosion cracking, resulting in equipment damage. Therefore, it is particularly important to choose high-performance materials that can withstand these corrosive environments.

2. Propylene oxide production equipment anti-corrosion material selection criteria

When selecting anti-corrosion materials for propylene oxide production equipment, the following criteria need to be considered:

(1) Corrosion resistance

The material must have excellent corrosion resistance and be able to resist various corrosive media in the production process. For example, in a strong oxidizing acidic environment, the surface of the material should be able to form a stable passivation film to prevent further corrosion.

(2) Mechanical properties

Although corrosion resistance is the primary consideration, the mechanical properties of the material (such as strength, toughness and wear resistance) cannot be ignored. Especially under high temperature and high pressure conditions, the material needs to have sufficient strength to withstand pressure, and at the same time have a certain plastic deformation ability to adapt to the dynamic load of equipment operation.

(3) Economy

The choice of material should also take into account its cost-effectiveness. Although certain high-performance materials (such as Hastelloy) are more expensive, their corrosion resistance and long service life can often make up for the initial investment, thereby reducing overall maintenance and replacement costs.

(4) Processing performance

The workability of the material is also an important factor. Propylene oxide production equipment usually requires complex structural design, so the material should have good processing performance to meet the needs of equipment manufacturing.

3. Hastelloy in propylene oxide production equipment application

Hastelloy (Hastelloy) is a high-temperature alloy based on nickel, which is widely used in chemical, petroleum, aviation and other fields because of its excellent corrosion resistance and mechanical properties. In propylene oxide production equipment, Hastelloy is particularly suitable for the following scenarios:

(1) resistance to wet chlorination and oxidation acid corrosion

Hastelloy has strong corrosion resistance to wet chlorination and strong oxidizing acid. In the propylene oxide production process, the equipment may be exposed to wet chlorinated gases or media containing oxidizing acids, and Hastelloy can maintain stable performance in these harsh environments.

(2) High temperature stability

The production process of propylene oxide usually requires a higher reaction temperature, and Hastelloy can still maintain excellent corrosion resistance and mechanical properties at high temperatures, which can meet the operating requirements of equipment in high temperature environments.

(3) good processing performance

Although the processing of Hastelloy is difficult, with the development of modern manufacturing technology, through reasonable process design and processing methods, the material properties can be maintained to meet the manufacturing needs of propylene oxide production equipment.

4. Other corrosion resistant material selection

In addition to Hastelloy, propylene oxide production equipment can also choose other corrosion-resistant materials, such as titanium alloys, stainless steel, coating materials, etc. Each of these materials has its own characteristics and applicable scenarios. For example, titanium alloys have extremely high corrosion resistance, but their strength and plasticity at high temperatures may not be as good as Hastelloy alloys; while stainless steels perform well in moderately corrosive environments, but may not be as durable as Hastelloy alloys in highly corrosive media.

Therefore, when selecting materials, it is necessary to comprehensively consider the performance, cost and processing feasibility of the material according to the specific corrosive environment and the working conditions of the equipment, and make a scientific and reasonable selection.

5. Summary and Prospect

The selection of anti-corrosion material for propylene oxide production equipment is a complex and important issue, which requires comprehensive consideration of the corrosion resistance, mechanical properties, economy and processing performance of the material. As an excellent corrosion resistant material, Hastelloy has a wide range of applications in propylene oxide production equipment. With the advancement of technology and the development of new materials, more high-performance materials may be used in this field in the future, thereby further improving the reliability and service life of equipment.

For propylene oxide production enterprises, the selection of appropriate anti-corrosion materials can not only improve the operating efficiency of equipment, but also reduce maintenance costs and achieve sustainable development of production. Therefore, in-depth understanding of the corrosive environment of propylene oxide production equipment and selecting suitable materials according to actual needs are important issues that every chemical industry practitioner needs to pay attention.