How to not let fouling bog you down

One of the major ammonia producers in Asia used a coil-wound heat exchanger as a lean/rich interchanger in its acid gas removal system. This heat exchanger was cleaned using cleaning in place (CIP) every 1-2 years. But after a while, cleaning with CIP wasn’t bringing the heat exchanger back to full capacity. An investigation revealed fouling in the heat exchanger that could not be removed using CIP. Since a coil-wound heat exchanger cannot be cleaned mechanically, the company had no choice but to replace the unit.

Alfa Laval proposes a solution

The company’s engineers searched for a solution where fouling could be completely eliminated during cleaning, and efficiency maintained over time. Alfa Laval proposed complementing the shell-and-tube heat exchanger with four Compablocs to boost capacity. Because Compablocs provide high thermal efficiency, they’re much smaller than comparable shell-and-tube heat exchangers and can usually be installed in the available space. The company installed two pairs of Compablocs in series with the existing shell-and-tube. The four Compablocs recover 14 MW.

Maintained performance and uptime

The Compablocs have performed according to specification, and after three years of continuous operation there was still no need for cleaning. Pressure drops were the same as when the heat exchangers were installed and thermal performance has decreased only marginally. Replacing their existing coil-wound heat exchanger with four Alfa Laval Compablocs eliminated the performance problems caused by severe fouling – and incomplete cleaning – that the plant struggled with before.