Quality wins - again

What no gasket can withstand
Bao Shan in Shang Hai have three production lines for Coke Oven Gas (COG) refining, each one with a yearly production of 150,000 tons/year. They use Alfa Laval products for a number of processes, including decanters for the coal tar recovery process, and have a total of 53 units installed. Recently, they switched back to the Alfa Laval brand (from the products of a local manufacturer) for the cooling of
lean ammonia in the COG plant. They now use six Alfa Laval spirals instead, each one cooling 110 m3/hour of lean ammonia from 35 to 27 °C. The amount of ammonia in the COG is reduced for two main reasons. First, the importance of ammonia as a byproduct. Second, ammonia is destructive to
the process equipment. In fact, it’s so corrosive that no gasket can withstand its harsh environment and tendency to foul. A gasket-free spiral, therefore, is a logical choice.

Not all spirals are created equal
However, when Bao Shan switched to a local manufacturer’s low-price product, they found that the quality wasn’t up to par. The product didn’t have any gaskets that could be corroded, but it was difficult to clean. And that resulted in a number of problems. “They had a more favourable price, but maintenance and service of those units was very time consuming,” says Bao Shan’s equipment director, “and the lifetime of the product was much shorter.”

The design is what makes them cost-efficient
The Alfa Laval spirals, on the other hand, last 20 years – four or five times longer than the local products. The combination of single-channel technology, the spiral shape, and the hinged door design are what make the Alfa Laval spirals long-lasting and cost efficient to maintain. With no internal supports, no sharp bends and no rough edges where solids can clog the channel, the turbulence in the Alfa Laval spiral acts as a constant scrubbing action. The fluid is fully turbulent at a much lower velocity than in straight tube heat exchangers, reducing the likelihood of dead spots and
stagnation. This self-cleaning effect flushes away deposits as they form, resulting in minimal fouling and low maintenance. And when service and cleaning are required, the hinged door and easy-clean hook bolts are easy to open, exposing the entire channel for cleaning.

When leaders come together It’s important for Bao Steel to maintain excellence in all their processes
in order to produce high-grade quality products and maintain their position as a leading steel manufacturer. With 50 years’ experience, Alfa Laval is helping them meet their goals. Based on their
experience with Alfa Laval’s products and service engineers, Bao Steel’s equipment director says that they feel confident they’re on the right track. “Working with a company with such a broad range of on site experience and innovative character, we feel inspired by their pioneering, and it makes us confident that we can continue to lead the way in our area of operation.”