From Waste to Resource: Avoiding Fouling in Ammonia Recovery

Abstract:

With recent ammonia prices soaring, technologies for recovering and repurposing ammonia have become essential in transforming waste into a valuable resource. However, engineers face challenges in extracting ammonia from diverse aqueous streams, requiring careful selection of the most suitable technology. While distillation is a prevalent choice, fouling presents a significant hurdle as undesirable substances accumulate on heat transfer surfaces, reducing overall process efficiency. Early implementation of effective fouling control strategies is crucial for ensuring reliable and efficient ammonia recovery. 

This article proposes a design solution to address fouling by replacing the overhead shell-and-tube condenser of a distillation column with a direct contact condenser (DCC). The DCC prevents the formation of solid compounds resulting from carbon dioxide and ammonia, allowing for higher carbon dioxide levels in the feed. Consequently, the system can operate reliably with reduced downtime for cleaning. The DCC resembles a miniature stripping tower, often equipped with tower packing inside a cylindrical shell, ensuring sufficient mass transfer area between the hot condensing vapor and the cooled incoming recirculation liquid.
Explore further insights on enhancing ammonia recovery efficiency with direct contact condenser technology in "From Waste to Resource: Avoiding Fouling in Ammonia Recovery" by Koch Modular’s Chris Rentsch and Allan Fox.