About the Client
Royal Avebe is a cooperation of approximately 2,000 farmers from the Netherlands and Germany. The starch potatoes of these members are processed annually into high-quality ingredients based on potato starch and protein, where they offer added value worldwide in food, but also in industrial applications.
At the potato starch factory (AMF) in Ter Apelkanaal, potatoes, starch and protein are extracted. To this end, Avebe uses dryers to process the potato raw materials. This results in emissions of particulate matter via the drying processes. In order to comply with increasingly stringent regulations and minimize the impact on the environment, Avebe has the ambition to drastically reduce the emissions of these dryers.
Challenge
Avebe was faced with the challenge of reducing the emissions of 3 dryers to a maximum of 20 mg/m³, in line with the permit requirements. This required a significant upgrade of the existing emission reduction installations, such as the wet scrubbers. Additionally, the implementation had to be completed in time to ensure operation before the start of the annual harvest campaign in September.
Next to emission reduction, Avebe was also interested in possible heat recovery to improve energy efficiency. This meant that not only dust reduction and emission emissions were considered, but also possibilities to recover energy from the flue gases.
Approach
JOA conducted an extensive Pre-Engineering Study to develop an optimized solution. The approach consisted of the following steps:
Site Visits and Measurements:
- Inspection of the current production line setup.
- Measurements of the existing wet traps, including air pressure, temperature and humidity.
- Interviews with operators and maintenance staff to identify operational challenges.
Air Technical Modeling and CFD Simulations:
- Creation of an air-technical model for the AMF lines based on measurement data.
- CFD modeling of the wet traps to better understand the behavior of the airflow and droplet formation.
- Simulations to analyze the interaction between the airflow and the nozzles, with the aim of achieving higher efficiency in dust collection.
Development of solution directions: JOA presented three possible solutions to Avebe during a 50% meeting
- Upgrade of existing wet scrubber: adjustments to the wet scrubber installations per dryer, such as improved nozzles and higher liquid-to-gas ratio.
- Central upgrade of wet traps: optimization of the recirculation and reuse of water in a central tank.
- Replacement of the wet traps with scrubbers: Implementation of JOA Inline Venturi Scrubbers, which ensure more efficient capture of dust particles and enable a low emission limit.
Concept design and budget quote:
- Development of conceptual layout drawings and implementation planning and budget.
- Analysis of the impact on energy consumption and pressure drop.
- Proposal for a phased approach, in which one wet scrubber would first be adapted as a proof-of-concept.
Outcome
After evaluating the proposed solutions, Avebe opted for the central upgrade of the wet traps. This approach provided a balance between cost, implementation time, and effectiveness. The solution includes:
- Smooth implementation process: Thanks to the Pre-Engineering Study, a tight implementation plan was drawn up, taking into account the potato harvest period. This allowed the system to be implemented immediately, without delaying production.
- Replacement of existing nozzles with spiral full cone nozzles, which ensure a smaller droplet size and higher efficiency in dust capture.
- Increased the liquid-to-gas ratio from 0.18 to 0.4 to achieve a better interaction between dust particles and water droplets.
- Installation of drip eliminators on the outlet of the wet scrubber to minimize loss of small water droplets.
- Conversion of the wet trap water tank into a recirculation tank, allowing the system to operate more efficiently without placing additional tanks in the dry zone.
- Improvement of airflow and pressure distribution through optimized pipe diameters and pump capacities.
With this new configuration, the emission limit value of 20 mg/m³ will be achieved and may offer opportunities for further optimization in the future.
In addition, it was investigated how the energy content of the waste gas stream could be used for heat recovery. By using a heat pump, the residual heat from the flue gas could possibly be used for other processes within Avebe.
This project exemplifies how innovative engineering solutions can drive significant environmental and economic benefits, supporting global efforts toward sustainability and energy efficiency.
Conclusion
Thanks to the Pre-Engineering Study, Avebe has an effective and feasible solution to meet with the strict emission standards. The chosen approach not only offers direct emission reduction, but also operational benefits such as more efficient water use and heat recovery opportunities.
Based on the Pre-Engineering Study, the chosen solution has led to a successful implementation. Emissions targets are being met and production has not been delayed during the installation of the system.
This case shows how in-depth analysis, modelling and simulation at an early stage lead to better and cost-effective solutions to industrial emission challenges.
