Field Reports

Fabricating a specialized processing vessel begins with design and engineering

custom processing equipment — When Tate & Lyle needed customized, complex processing vessels, it turned to Mitternight to provide the equipment.

*Photo courtesy of Mitternight*

Tate & Lyle is a global supplier of ingredients to food and beverage markets. When constructing its plant in McIntosh, Ala., the company required custom-designed distillation columns, pressure vessels and heat exchangers. Because of high operating temperatures and pressure, specialized solutions were required for performance and durability. Moreover, the company needed equipment that could run 24/7 with only two shutdowns a year.

These vessels must endure high temperatures and high pressure over decades of grueling use. They are critical pieces of operating equipment that often function as the central processing units of an entire manufacturing facility. As a result, any equipment downtime can be extremely costly to the operator.

“At the time, the engineering team only provided a fabricator with a data sheet of the requirements—things like how many gallons for the vessels, operating temperatures, pressure levels, and how many nozzles were needed. From there, we needed the vendor to come up with the equipment design and be able to build it to ASME Section VIII Div. 1 code,” says Linda Rutherford, a member of the quality control department at Tate & Lyle.

There are relatively few vendors worldwide who provide the in-house design and engineering expertise to craft vessels that can withstand high intensity environments. Leading fabricators certify their vessels with the American Society of Mechanical Engineers to indicate that their products fulfill the requirements of relevant ASME codes and standards.

Based on a combination of capability, quality, service and price criteria, Tate & Lyle partnered with Alabama-based Mitternight, a fabricator specialist that holds certifications in ASME Div. I and II stamps, as well as a Chinese License for Pressure Vessels A2. The company designed and engineered the plant’s original separators, heat exchangers, storage tanks and pressure vessels. Given the operating parameters, the company built the equipment, which included fabricating pressure vessels more than 100 feet tall, using stainless, specialized alloys.

Complex design and engineering

The work of fabricating a specialized processing vessel first begins with design and engineering.

Then, fabricating to meet the performance specifications requires expertise and craftsmanship in metallurgy. And specialized alloys selected for their performance attributes can themselves be inherently challenging. Welding specialized high-grade nickel alloys of up to 99% nickel, such as Nickel 200 for example, is a demanding process.

Sometimes the creators need to literally write the manual through the process of fabricating the vessel and work with metallurgists on the client side who require certain things without the benefit of any real precedent in the market because the weld has never been made before.

Industrial quality control specialists like Tate & Lyle’s Rutherford regularly monitor the thickness of vessels to ensure they remain in specification.

“A key to durability is selecting the right metals in the first place,” says Rutherford. “Then when repairs and maintenance are needed, the code work needs to be completed and recertified. We’ve asked them to repair and complete replacements of pressure vessels and heat exchangers.”

With so much invested in the performance, safety and durability of complex process vessels, operators can find a lot of value in working with a fabricator who not only has expertise in specialized metal alloys but who can partner with them through the entire design-engineer-fabricate-test-support continuum.

Vertical integration means more control, and control means making deadlines. Delivery is critical because we can be talking about millions of dollars a day at risk for a client. When you can control the entire process, you have a much better chance of meeting delivery deadlines.