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The Rise of Zirconium Clad Equipment in Acetic Acid Processing

Acetic acid is a chemical backbone of the modern world. This organic compound is used in a variety of industrial and consumer goods, like clothing, plastics, medicines, perfumes, paints and food additives.

 

Behind these goods stand the world’s acetic acid producers who provide the colorless liquid to a range of manufacturers, including the vinyl acetate monomer industry. Of the world’s producers, Asia is the largest, accounting for most of the total global production, followed by North America, Europe and Middle East. To keep these acetic acid operations running reliably and safely, today’s fabricators and engineers rely on one metal—zirconium. However, that was not always the case.

 

In the late 1970s and early 1980s, acetic acid producers found they had a problem. The most important operating equipment they installed—nickel alloy reactors and piping systems—was corroding and suffering mechanical failure in hot, high-pressure processing environments, resulting in costly rebuilds and production downtime.**

 

Chemical processors looked to replace nickel alloys with another, more reliable metal. With its exceptional corrosion-resistant properties, zirconium was an attractive option, although it was expensive and had design limitations.

 

In 1985, one fabricator turned to zirconium explosion cladding and started, what would become, a global shift toward zirconium clad reactors, and related equipment, for acetic acid production—a trend that has continued until today.

 

Now, there are more than 50 zirconium clad reactors in operation worldwide. Most of these reactors use Zr700, a commercially pure and highly formable grade of zirconium, clad to carbon steel.

 

The Value of Zirconium Clad for Acetic Acid Production

For more than 30 years, engineers have resorted to explosion welding to economically add the corrosion-resistant strength of zirconium to their process equipment designs.

 

Explosion welding is a solid-state, cold-welding process that uses precise detonations to force, or bond, dissimilar metals together while preserving the physical, mechanical and corrosion-resistant properties of each metal. Explosion welding is also the only practical method to effectively produce a durable, high-strength bond between large sheets of reactive metals, like zirconium and steel.

 

About 90 percent of the world’s acetic acid production uses the Methanol Carbonylation method. The method requires safe, reliable zirconium clad equipment**, including:

  • Large reactors with walls up to 100 mm (4 in) thick*;

  • Heat exchanger tube sheets up to 100 mm (4 in) thick*; and

  • Large columns up to 5 m (15 ft) in diameter and 40 m (130 ft) high.

 

The functional benefits of using zirconium clad in these applications are many—from lifetime equipment savings to design flexibility, project continuity and safety. However, these benefits are only fully realized with the right clad partner, a partner with quality processes and expertise to protect your investment, from specification to delivery and support.

 

Why NobelClad

Few people in the world know how to do what we do, and even fewer go beyond ASTM B898, the global standard specification for reactive and refractory metal clad plates, including zirconium explosion cladding for acetic acid processing.

 

NobelClad’s zirconium clad plates are the largest commercially available plates, and they are two to three times larger than solid zirconium plates. With fewer welds, our large plates offer better reliability when used to manufacture pressure vessels, formed heads, heat exchanger tube sheets, and thick-walled clad piping and elbows.

 

Knowledge is the First Step to Creating Value

We believe in sharing our metallurgical expertise and invite you to contact us to sign up for a free, 60-minute webinar – An Introduction to Zirconium Cladding Technology. We will cover:

Design strategies for reducing CAPEX;
Keys to zirconium clad project reliability & success; and
Practical examples of zirconium clad equipment in the chemical processing industry.

 

* NobelClad manufactures much thicker plates for reactors and tube sheets, but these thicknesses are most common for acetic acid.

** J. Banker, "Explosion Cladding: An Enabling Technology for Zirconium in the Chemical Process Industry," Journal of ASTM International 7, No. 8 (2010): 1-10. https://doi.org/10.1520/JAI103050

**B. J. Sanders, "Zirconium Corrosion Resistance: Key to Success of the Methanol Carbonylation Acetic Acid Process," in Zirconium Production and Technology: The Kroll Medal Papers 1975–2010, ed. R. Adamson (West Conshohocken, PA: ASTM International, 2010), 439-446. https://doi.org/10.1520/MNL12127R

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