How can you select materials for chemical processing that resist fire and explosions?

1 Material properties

When selecting materials for chemical processing, it is important to understand the material properties that affect their resistance to fire and explosions. These include thermal conductivity, which determines the ability of a material to transfer heat; thermal expansion, which affects size or shape changes due to temperature; melting point, which is the temperature at which a material changes from solid to liquid; flammability, which is the tendency of a material to catch fire or burn; and reactivity, which is the tendency of a material to undergo chemical reactions with other substances. High values of each property can prevent certain risks but also increase the risk of other potential hazards. It is essential to consider these material properties in order to ensure safety and optimal performance.

2 Material selection

In selecting materials for chemical processing, the second step is to compare the material properties with the process conditions and requirements. This includes identifying the process fluids and their physical and chemical properties, like temperature, pressure, phase, composition, concentration, purity, corrosiveness, toxicity, and flammability. Additionally, you must determine the design specifications and operating parameters of the equipment, such as heat transfer rate, pressure drop, flow rate, duty cycle, maintenance frequency, and safety factor. Furthermore, you must evaluate the material options and their advantages and disadvantages in terms of cost, availability, durability, reliability, compatibility, and ease of fabrication and installation. Finally, you must apply material selection criteria and methods such as charts, tables, rules of thumb, standards, codes, or software tools to rank and select the best material candidates for the application.

3 Material examples

The third step in selecting materials for chemical processing is to examine material examples and their applications in heat exchangers and boilers. For example, carbon steel is a common and economical material that has moderate thermal conductivity, thermal expansion, melting point, flammability, and reactivity. It is suitable for low to medium temperature and pressure applications, but it can corrode, oxidize, or crack under high temperature or corrosive conditions. Stainless steel is a widely used and versatile material that has high thermal conductivity, thermal expansion, melting point, and reactivity but low flammability. It is suitable for high temperature and pressure applications, and it can resist corrosion, oxidation, and cracking. Copper is a superior material that has very high thermal conductivity, thermal expansion, and melting point but low flammability and reactivity. It is suitable for high heat transfer and low pressure applications, but it can also be costly, soft, or incompatible with some process fluids. Lastly, nickel is a special material that has high thermal conductivity, thermal expansion, melting point, and reactivity but low flammability. It is suitable for extreme temperature and pressure applications but can also be very expensive, scarce, or difficult to fabricate or install.