HAELEN, NETHERLANDS — Geelen Counterflow developed the Counterflow Recovery Unit (CRU) with the goal of recovering as much energy and water as possible from its counterflow dryers for extruded petfood, aquafeed and food.

Two years of thermodynamic and CFD- (Computational Flow Dynamics) modeling lead to a prototype that was tested full-time during eight months in a commercial production line.

The Counterflow Recovery Unit is a top-down vertical heat exchanger in stainless steel that recovers up to 75% of the energy and water from a counterflow dryer’s exhaust air, while avoiding the excessive fouling by fines and fats that often make the use of industrial heat exchangers so difficult.

Dryers are the biggest energy consumers of any extrusion process. Typically, up to 60% of the energy consumption of an extrusion plant is used to generate hot air to evaporate moisture from the product. After passing the product, the dryer’s warm exhaust air with high relative humidity transports the moisture out of the dryer. It makes a lot of sense to recover the latent energy in that warm air through condensation before it is discharged, the company said. Condensing the air also will significantly reduce the number of odor particles in the air.

Together with an electric heat pump and heat exchangers for the drying air, the Counterflow Recovery Unit can eliminate the need for fossil fuels for drying of extruded petfood, aquafeed and food products.

During 2021, Counterflow Recovery Units will be installed in petfood and aquafeed plants in South Korea, China and Norway by customers that plan to eliminate their CO₂ emissions in the next few decades.