Chemical & petrochemical processing

Stainless steel with 6% Mo improves equipment efficiency and eliminates costly repair. This case study has been provided by Thomas Stoner of Hercules Incorporated and Kelly Wyrough of Roben Manufacturing and was written by IMOA consultant John Grocki.

Chemical tankers are specialized ships carrying liquid cargoes that may be environmentally hazardous, flammable or highly reactive. They are designed and operated under special rules, and increasingly have built-in molybdenum-containing stainless steel tanks. Sailing around the world, they transport liquid goods safely over long distances. They represent a significant market for duplex stainless steels and molybdenum.

Offshore oil and gas platforms see some of the most demanding environmental conditions for construction materials anywhere. Exposed to extreme weather, wind and waves, these structures must operate safely for decades. The most challenging sites are located in or near the Arctic oceans, where frequent storms intensify the extremely corrosive exposure to seawater. Molybdenum-containing alloys, especially duplex and super duplex stainless steels, last longer than almost all other materials in these difficult situations. One small but critical example is super duplex bolts.

It is no exaggeration to say that the tank container has revolutionized freight transport. From its humble origins, the ISO tank container industry now numbers more than half a million units across the globe. Tank production is growing at nearly twice the rate of the world economy and they are almost always made of molybdenum-containing stainless steel. Such is their popularity that these containers now represent a significant end-use application for molybdenum.

Duplex stainless steel storage tanks are increasingly being used due to their long, low-maintenance service life. Surprisingly, they can also reduce initial costs for tank owners. The higher strength of duplex grades permits thinner walls requiring less steel. Because costly protective coatings or cathodic protection are not necessary, they can compete on installed cost with carbon steel tanks.

Maritime shipping remains one of the most cost-efficient global transport methods, especially compared with air freight. Its rapid growth since the 1970s and the containerisation of cargo have kept pace with the global economy, however this has also increased its environmental impact. New regulations limiting the sulfur content of engine fuel mean that ships must either use cleaner, more expensive fuel, or install equipment to take sulfur out of exhaust gases, a process in which molybdenum plays a key role.

It can be difficult and time consuming for engineers to find materials properties beyond the basic ones reported in producer data sheets. This is especially true for lesser-used high-performance alloys. The new High-Performance Alloys Database addresses this problem. It contains a large number of materials properties for each of the 100 or so featured alloys, many involving molybdenum.

Clean air is a basic human need for a healthy life. Yet, advances in living standards (electricity on demand, automobiles, and consumer goods) contribute to air pollution in manufacturing, energy production, and the use of products. As scientists began to understand the connections between air pollution and industrialization, engineers developed technologies to minimize the damage. Molybdenum plays a central role in many of them.

Molybdenum compounds have been used in commercial pigments for over a hundred years. They continue to play an important role in today’s sustainable and environmentally safe colorings.

A recent study found that about one quarter of the molybdenum used each year is recycled material from scrap sources. The rest is newly mined, primary molybdenum. Scrap therefore plays an important role in meeting demand and contributing to sustainability.

Molybdenum-bearing stainless steel enclosures for electrical, electro-mechanical and electronic equipment generally go unnoticed, but are very important. These enclosures are used in chemical plants and at other industrial sites with corrosive environments. They protect vital systems and instruments from chemicals, fumes, moisture and even fires or explosions.

Stainless steel wire and rod are used to manufacture a wide variety of woven steel mesh products. They are used in many applications ranging from the eye-catching and spectacular to the unobtrusive and utilitarian. Molybdenum contributes to their growing popularity and success by improving corrosion resistance.