Pet food sector: odor reduction with osmogenic barrier

In companies that produce animal food, problems with smelly emissions often occur.

Generally, these odors are linked to the processing of raw materials to obtain the finished product, as in the case of an industry in central Italy that contacted us for a problem with odorous emissions generated during three specific processing phases: extrusion, drying and cooling.

The pet food processing stages that cause bad odors

Let's know in more detail at what these three phases consist of.

Extrusion

The product is cooked with a relative reduction of the bacterial load, making it safe from a microbiological point of view through the action of temperature (above 100°C) and pressure (on average between 20 and 40 bar).

Limited to the production of fresh meat sticks, the extrusion process occurs cold, with the shaping of meat cords, subsequently cut using a special cutter and sent to the cooking oven.

Drying

Using a methane or steam dryer, temperatures are reached that allow, with an adequate process time, the evaporation and removal of excess water that the product absorbs in the previous phases. In this way, humidity is reduced, ensuring greater stability to the product.

In the production of fresh meat sticks, the drying production process takes place in a ventilated tunnel oven. In this case, drying coincides with the slow cooking of the product at low temperature (about 70°C for 4 hours).

Cooling

Cooling products with a forced air flow at room temperature helps avoid condensation in the subsequent storage phase, ensuring greater product stability over time.

Our customer's critical emission points, linked to the three production phases described above, were seven in total:

• 2 dryers/extruders with cyclone abatement
• 1 dryer exhaust suction system
• 1 extrusion system with cyclone abatement
• 2 vertical coolers - extruders with cyclone abatement
• 1 horizontal cooler - extruder with cyclone abatement.

After studying the situation and the data provided by the customer on the effluents to be treated, our technicians developed a customized project for the emission criticality.

We conveyed the air from the seven emissions into a single steel plenum.

The plenum was used as a calming chamber to obtain the optimal conditions in terms of air speed and therefore guarantee the contact time necessary for our neutralizing product LT Air Plus, diluted to the optimal concentration, to best perform its activity of reducing the odor concentration.

In the lower part inside the calming chamber, six stainless steel bars were inserted, each equipped with five nebulizing nozzles.

Two additional bars were positioned in the upper part of the plenum. The whole thing is managed by a nebulization system called HPS Midi Plus.

Through the use of our osmogenic barrier, the customer has found a significant improvement in odorous criticalities, also demonstrated by olfactometric investigations that have detected a reduction in odor concentration equal to 78%.

The customer has signed a total maintenance contract.