It has to get wet to get dry – The wet process
There are two different possibilities to extract the protein out of the raw materials: the dry and the wet process. Both process alternatives produce protein powder or “meal” as well fat but investment and operational costs are different. In a nutshell you can say that the wet process is higher in investment than the dry process but is clearly superior when it comes to running costs. That means that the higher the capacity of a planned project the more advantageous the wet process.
The dry process uses a drier to separate the water from the insects, the wet process separates the water via a decanter centrifuge so that it can be evaporated.
Focus: energy consumption
It's the energy costs that make the main difference here. While in the dry process the insects are dried before protein and fat are removed, it is exactly the other way around in the wet process. Heart of the wet process is the unbeatable combination of 3-phase decanter and evaporator. The decanter separates the ground insect larvae into fat, suspended solids (protein phase) and water. And it is exactly this step that reduces the energy demand for the overall process significantly. While in the dry process the water content of the insects is exclusively removed by drying – a very energy-intensive method to eliminate water – the wet process removes most of the water before the drying stage and evaporates it with a falling film evaporator – a much more energy-efficient way to eliminate water.
So, the wet process removes a substantial amount of water from the insects before they reach the drier which makes for significantly reduced energy costs.
Decanter and evaporator - The dynamic duo of efficient insects processing
The combination of decanter and evaporator removes a substantial amount of water from the insects before they reach the drier which makes for significant energy savings. And energy is one of the big cost drivers in insects processing.
3-phase decanter
Decanter centrifuges separate liquids from solids.
Falling film evaporator GEA CompaCon
Evaporators are used to concentrate all kinds of liquids.
OPEX split for insects processing
Energy is one of the main cost drivers in insects processing.
Energy footprint, protein quality, fat purity
But the wet process has even more benefits than just the energy footprint. One is the quality of the recovered fat. A centrifugal separator polishes the oil phase from the decanter which results in a pure fat with almost no residuals of solids and water. Another benefit is the higher protein quality. Removing the fat from the larvae before drying increases the protein content of your meal. It also makes for a lighter color of the meal as the high temperatures in the drier burn the fat. The purer and more neutral a protein the more manifold the possible fields of application for subsequent feed or food purposes.
The wet process produces a bright and pure fat as well as high quality protein, in this case from the larvae of Black Soldier Flies (BSF).
Insects processing in a nutshell
- Two main processes for insects: dry and wet process
- To each his own: dry process recommended for small, wet process for higher capacities
- Energy consumption: Substantial energy savings with wet process
- Product quality: Better oil and protein meal quality with wet process
- Flexibility: Product and process flexibility higher with wet process
- Test before invest: Let’s talk and investigate your product and needs to find the best solution for you
