About the Client
This project was executed at a large producer of potato-based ingredients in Western Europe, processing starch potatoes into high-quality products based on potato starch and potato protein for food and industrial applications.
At one of the client’s potato starch production sites, multiple drying lines are used to process raw materials. As a result, particulate matter (dust) is emitted via the drying off-gas streams. With tightening regulatory expectations and a clear sustainability ambition, the client set out to drastically reduce dust emissions from these dryers while maintaining reliable operation during seasonal peak production.
Challenge
As there was a need to reduce the emissions of three dryers to a permit-compliant dust emission level (in the order of tens of mg/m³), a significant performance improvement was required of the existing dust abatement equipment (wet separation systems), without introducing unacceptable downtime or operational risk.
In addition to dust reduction, the client wanted to understand whether heat recovery from the dryer off-gas could be feasible and financially attractive. This is why the project needed to address both emissions compliance and energy efficiency opportunities.
A key constraint was timing: the upgraded systems had to be ready for operation ahead of the seasonal campaign, when production volumes are highest and shutdown windows are limited.
Approach
JOA conducted an extensive Pre-Engineering Study to develop an optimized, and implementable solution adjusted to the site requirements. The approach consisted of the following steps:
Site Visits and Measurements
- Inspection of the existing dryer lines, ducting, and wet separation equipment.
- Field measurements on the current wet systems, including pressure, temperature, and humidity. Also related operating conditions relevant for wet collection performance were taken into account.
- Interviews with operations and maintenance teams to capture operational constraints, maintenance pain points, and realistic implementation windows.
Air Technical Modeling and CFD Simulations
To identify bottlenecks and to validate the concept design of every extraction system, we execute extensive calculations and make use of CFD simulations. With JOA’s in-house developed Air Technical Modeling software, we are able to predict future outcomes. For this case, we used:
- Development of an Air-technical Model of the relevant lines based on measured data, to quantify flow distribution, pressure losses, and system boundaries.
- CFD modeling of key wet separation components to better understand airflow behavior, droplet formation, and areas where collection efficiency was being limited by internal flow patterns.
- Simulation studies focusing on the interaction between airflow and spray/nozzle configuration, aimed at improving dust capture efficiency while avoiding carry-over and unstable operations.
Air-technical modelling was used to validate conceptual architectures, expected stability, and feasibility under typical simultaneity assumptions.
Development of solution directions
After alignment during a ‘50% Meeting’, JOA presented three solution routes during a structured midpoint design review:
- Upgrade of existing wet scrubber systems (per dryer): targeted modifications such as improved spray hardware, optimized operating window, and increased liquid-to-gas interaction to raise capture efficiency.
- Central upgrade of the wet separation water system: optimization of recirculation, water reuse, and hydraulic stability via a central approach. This reduced complexity at the individual lines while improving consistency.
- Replacement with scrubbers: evaluation of implementing JOA Inline Venturi Scrubbers as a robust route toward lower dust emissions, with predictable performance and a clear path to stringent emission limits.
Concept design and budget quote
The end result of a Pre-Engineering Study is the best possible Concept Design of a system, including a Budget Quotation. All decisions are documented in an extensive report, including:
- Conceptual layouts, tie-in philosophy, and an implementation plan aligned with production constraints.
- Evaluation of impact on pressure drop, energy consumption, and operational stability.
- Proposal for a phased execution strategy, including the option to implement one line first as a controlled proof-of-concept before rolling out to the remaining dryers.
Outcome
After evaluating the solution directions, the client selected the central upgrade of the wet separation (wet trap) system, as it provided a strong balance between CAPEX, implementation time, and emission reduction effectiveness, while also keeping operational disruption manageable.
The implemented concept included:
- Controlled implementation planning: the Pre-Engineering Study enabled a tight schedule aligned with the seasonal campaign, minimizing production risk and avoiding delays.
- Spray and droplet optimization: replacement and upgrade of nozzle technology to improve droplet distribution and dust capture efficiency.
- Increased liquid-to-gas interaction: a substantial increase in liquid-to-gas ratio to improve contact between dust particles and droplets, while maintaining stable hydraulics.
- Mist control improvements: installation of outlet droplet separation of drift and mist eliminators to reduce carry-over and water loss.
- Recirculation and water system optimization: conversion and repurposing of existing tankage for more effective recirculation, improving robustness without adding unnecessary equipment in constrained areas.
- Flow and pressure distribution improvements: targeted ducting and pumping optimizations to stabilize operating conditions and improve overall system controllability.
With this configuration, the system is designed to achieve the required permit-level dust emissions, while also creating a platform for further optimization where needed in the future.
In parallel, the study evaluated heat recovery potential from the dryer off-gas stream. A conceptual option identified was the use of an industrial heat pump to upgrade low-grade waste heat for re-use elsewhere on site, subject to integration constraints and business-case validation.
Conclusion
The Pre-Engineering Study delivered an effective and feasible route to meet stricter dust emission requirements for three dryer lines, within real-world operational constraints. Beyond compliance, the selected concept improves day-to-day operations through more stable hydraulics, more efficient water use, and clearer controllability of key parameters that influence separation efficiency.
This case demonstrates how early-stage measurement-based engineering, supported by Air Technical Modeling and CFD, leads to practical, cost-effective solutions for industrial emission challenges, while also identifying realistic opportunities for energy efficiency improvements.
