OPTIMISED & USER FRIENDLY SOLUTIONS
Vapogant
Digestate evaporation
The Vapogant fermentation residue evaporation system acts as a nutrient manager by processing the fermentation residue from the biogas plant to produce a usable, concentrated fertilizer.
We use vacuum evaporation to remove the water content from the fermentation residue. At the same time, volatile nitrogen is bound so that losses during spreading are minimized and the nitrogen is available in the form of ammonium sulphate solution (farmAS®).
The aim is to use the available waste heat to thicken or refine 100% of the fermentation products produced in the biogas plant.
The plant is available in a module size of 400 kW or 500 kW.
The process
The fermentation residue evaporation process comprises several steps:
1. mechanical separation: fermentation residues are separated into liquid and solid phases through a sieve. The solid matter is stored temporarily and can be used as fertilizer.
2. heating and vacuum evaporation: The liquid phase is heated and placed under vacuum, causing it to partially evaporate and thicken. This is done in an energy-efficient process that uses heat recovery.
3. vapor scrubber: The gas phase is treated with sulfuric acid to convert ammonia into ammonium sulfate, which is stored separately.
4. condensation and cooling: The remaining steam is condensed into water and the heat recovered is reused. The distillate is cooled and used as a coolant.
5. vacuum generation and gas recirculation: A vacuum pump generates the necessary vacuum and feeds escaping gases back into the biogas plant.
6. discharge of the concentrate: The thickened concentrate is discharged vacuum-tight at the end and contains all nutrients except ammonia, which is stored as ammonium sulphate.
The system has a modular design and has an evaporation capacity of up to 2.5 liters per kW therm, depending on various operating conditions.
WHAT IS THE VAPOGANT CAPABLE OF?
Waste heat utilisation
- Efficient and sensible use of heat all year round
- Secure CHP bonus through efficient fertilizer production
- Simple integration into existing systems
(also for partial heat utilization) - Multiple use (multi-stage) due to vacuum system
- Heat recovery:
1. evaporation 2. Digester heating - Automatically controlled 100% heat reduction
Digestate storage capacity
- The thickened digestate has significantly less
volume and saves up to 70% of the digestate storage capacity - Digestate evaporation as an alternative to building
additional digestate storage facilities - No further digestate storage problem due to amendment of the AwsV and Fertilizer Ordinance
- Enormous thickening of the liquid phase
- possibly No hazardous incident ordinance necessary
Problem of 170 kg N limit
- Less volume means fewer journeys
(less strain on roads and population) - Fewer passes in the field thanks to
nutrients in concentrated form - The risk of weathering is reduced and the
impact during application is increased
Emissions
- 100 % closed system
- Full condensate treatment
- No odours
- No exhaust gases
- No noise (60 dB at 10 m)
- No particulate matter
- Vacuum pump recirculates exhaust gas to gas system of biogas plant or activated carbon filter
Nutrient management
- Use of nitrogen fertilizer above 170kg N limit
possible - Very low N losses during storage and application
- Upgrading the fermentation residue to a transportable ammonium sulphate solution (farmAS®) and concentrated
fertilizer (farmLC®) - Less nitrogen loss due to ammonia emissions
in the field, thus also saving on additional nitrogen purchases - Better nutrient management: nutrients can
be used much more effectively
and in a more targeted manner thanks to the separate nutrient fractions
Application/ fertilization
- Best nutrient management
- Increased nutrient concentration:
→ Lower weather risk
→ Fewer trips
→ Highest efficiency - Nitrogen losses are very low
- Significant reduction in fertilizer purchases
- Additional benefits through sulphur fertilization
How does the Vapogant work?
factfeeder
How does the Vapogant digestate evaporator work? Patrick Fries explains our Vapogant digestate evaporation technology in our video.
Vapogant digestate evaporation cycle
Technical process of Vapogant digestate evaporation
Use of the ammonium sulphate solution (ASS) obtained
The ammonium sulphate produced by the digestate evaporation system can be used further as customers see fit:
For your operation
farmAS® is dosed directly into the fermentation residue (thickened liquid phase) during application.
For commercial use
Introduction of the entire N requirement into the root zone
of a crop.
- Ammonium can be applied as required or as a depot
- farmLC® can be applied regardless of vegetation and crop
- Depot fertilization makes use of nutrients not yet available in the soil
Distillate use
The distillate discharged from the evaporation process, which has been cleaned using a vapor scrubber, can be further processed in different ways depending on the customer’s requirements:
Using the distillate for operation purposes
There are different options to use the distillate for operations: Storing the water to be used as washing water for stables and areas, as thinning water for pesticides and liquid fertilisers, etc.
Evaporation of the distillate through the wet cooling tower
As a cooling unit is needed to operate the plant, part of the water may also be evaporated continuously through a cooling tower. Additionally, the cooled water is used as a cooling medium.
Indirect and direct distillate introduction
The water is introduced continuously to a receiving stream, combined with an upstream distillate processing module if necessary, or it can be allowed to drain.
