Biomass Drying Systems Compared: FlowDrya, Belt Dryers & On-Floor Dryers

This article presents the technical differences in design and cost between three alternative methods of drying wet biomass materials: (1) Stronga FlowDrya, (2) Belt dryers and (3) On-floor drying systems. Costs are considered in terms of initial capital investment and ongoing operating expenses, which include energy, service and maintenance expenditure.

Choosing the right dryer influences profitability, safety, efficiency, and long-term sustainability.

FlowDrya, Belt Dryer and On-Floor Dryer comparison

Comparison of FlowDrya, On-Floor Dryer, and Belt Dryer systems

Comparing Design Complexity of Biomass Dryers

Why Design Simplicity Matters?

Having a dryer with a simple design is essential for a smooth-running and productive operation. Complicated dryers with a number of moving parts are more susceptible to operational challenges and repairs are costly and consume valuable time.

FlowDrya	Belt Dryer	On-Floor Dryer
Simple, strong and innovative structural design Few moving parts Powerful hydraulic power-pack Simple, long life and most low maintenance drying solution on the market	Usually highly complex with up to 54 bearings and 8 motors/gearboxes Moving parts wear over time Fragile belt and expensive-to-replace components Complex in-feed arrangement Increased fire risk if not adequately maintained	Highly inefficient Operationally complex, most grain on-floor dryers are inadequate for moisture heavy biomass Air-flow complexity beneath the floor to distribute air consistently across a large area

FlowDrya's simple, reliable design in operation

Biomass Dryer Lifespan & Maintenance Costs Compared

Investing in a reliable, sturdy and robust drying system is crucial. FlowDrya not only offers one of the longest service cycles available, but also the lowest maintenance costs and requirements.

FlowDrya	Belt Dryer	On-Floor Dryer
Long service life 8,000 annual operating hours Unique stop-start operation 4x less component wear Low service requirements Minimal maintenance costs	Multiple components work overtime Components run continuously Electric motors, gearboxes, bearings & shafts work continuously	Labour-intensive Unloading/telehandler loading increases labour costs and loader depreciation costs

Annual operating hours of FlowDrya vs Belt Dryer

Comparing Dryer Installation Cost & Time

Slow installations delay revenue, increase capital strain and create risk. FlowDrya's shorter and more simple installation process ensures no time is lost – allowing biomass drying operations to commence almost immediately after delivery.

FlowDrya	Belt Dryer	On-Floor Dryer
Fully assembled, modular and pre-commissioned at Stronga's factory Quick installation of monocoque sections Stronga team spend 2 days installing and commissioning the dryer Specialist training given to FlowDrya customers	Large structures with hundreds of parts and bolts Structure assembled onsite, increasing installation delays Once the 'super-structure' is bolted together and all complex moving parts are installed everything needs to be aligned	Planning permission often required for on-floor biomass dryers Uncertainty surrounding costs and sales process Often the longest installation periods

FlowDrya modular installation process

Comparing Electric Energy Consumption

In recent years, electrical energy costs have increased by more than 100% in some regions. FlowDrya offers 3x lower electrical demands than alternative drying systems; this leads to large financial and carbon savings.

Dryer Type	Electrical Demand	Key Factors
FlowDrya	Lowest demand	Stop-start operation, low motor usage, residual heat integration.
Belt Dryer	3–4X higher	Multiple motors, several paddle agitators, belt sweepers.
On-Floor Dryers	Medium–high demand	High fan back pressures, higher electrical parasitic load, telehandler usage.

Comparing Hopper Refill Frequency; Labour Efficiency

Labour costs and availability have become increasing concerns for businesses in recent years. Refilling frequency of the dryer has therefore become a key consideration if businesses are to remain competitive in the market.

Dryer Type	Hopper Size	Impact
FlowDrya	Very large hopper with extension side options (up to 8X belt dryer capacity)	Minimal labour requirements, full material agitation and pre-drying storage extends reloading intervals.
Belt Dryer	No hopper capacity, small infeed separate systems (5m³)	Requires full-time operator to keep motion even during overnight periods.
On-floor Dryers	No hopper	Extremely labour-intensive, no even biomass spreader integration or mixing for after-drying. One client was refilling bays every 4 days - these 'semi-hidden' costs are enormous.

FlowDrya motor-and-gearbox assembly

Comparing Material Agitation of Biomass Dryers

Thorough agitation is a fundamental component of an effective biomass drying process. Without agitation, biomass dries unevenly, wastes valuable energy, lowers yield and increases fire risk.

Dryer Type	Agitation Level	Outcome
FlowDrya	Full-depth mixing, PulseWave™	Unique, automatic and integrated full biomass mixing. Prevents over/under drying and allows for extremely even drying.
Belt Dryer	Minimal (flickers only)	Insufficient mixing and agitation – flickers contribute to higher electric costs and increasing complexity.
On-floor Dryer	None	Causes re-condensing 'fronts' effect, wet/dry layering. Manual agitation is extremely inefficient.

FlowDrya's large hopper capacity compared to belt dryers

Drying Process Control & Moisture Management Across Dryer Types

FlowDrya offers complete control of the residency time materials are on the drying bed via the HMI smart-controls. The touchscreen controls are fully self-protecting, intuitive and easy to use, allowing customers to set key parameters and monitor data and energy-use logs.

FlowDrya	Belt Dryer	On-Floor Dryer
Complete control over time biomass material is on the drying bed Smart-control console and DryStation™ HMI Strokes per hour control over output moisture (each stroke creates full agitation of the biomass depth)	Operate with only a thin layer of material on the bed Operators must manage belt tension and adjust the belt speed according to biomass, moisture content, ambient temperature and humidity variations Air-knife type fans, belt sweeper motors and flicker rotors add complexity and drying difficulty for the operator	No way of stopping the drying process, leading to overdrying at the bottom of the material pile and under drying at the top, common in grain dryers Wasted energy and time, reduced and uneven output Minimal control over biomass drying process

FlowDrya HMI control panel

Which Biomass Dryer has the Lowest Fire Risk?

Many clients only recognise fire dangers after experiencing fires and subsequently move to safer continuous flow drying systems.

FlowDrya	Belt Dryer	On-Floor Dryer
To our knowledge, FlowDrya systems have never been at fault for any fires Low temperature drying, indirect air, stop-start operations Very few slow moving parts and no bearings, chains or sprockets Extremely low fire risk	Significant fire risks due to overheated bearings, friction from slipping plastic belts, static electricity from polymer belts, and direct-flame heat sources Insurance companies mandate costly suppression systems	High fire risk Risk of overdrying material at floor level Loader buckets scrape the dryer surface and generate sparks that ignite biomass Fire spreads rapidly

Fire risk comparison between dryer types

What are the Space Requirements for Each Biomass Drying Method?

Physical land space has become increasingly valuable; a compact, modular biomass drying solution, enabled by deep-cycle drying, suits clients wanting to conserve valuable land.

Dryer Type	Footprint	Details
FlowDrya	Small (60 m² typical)	Very small footprint - deep bed drying (circa 500mm) + agitation enables a compact design.
Belt Dryer	Medium–Large	Requires long belt length due to shallow depth (150mm), potentially up to 3x bigger than equivalent FlowDrya.
On-floor	Very large (600 m²)	Building footprint plus yard space for access. FlowDrya occupies 10% of the space required.

Space requirements comparison between dryer types

Fines Removal & Screening Capability Compared

Fines separation ensures the main dry output material is clean. In some processes, such as gasification and pellet-making, it is vital to use clean material to reduce wear and extend the service life of equipment.

FlowDrya	Belt Dryer	On-Floor Dryer
In-built screen and fines fraction separation auger for soil and heavy small particles Small fines are collected in the sub-floor plenum and augured out FlowDrya is the only biomass dryer with built-in screening	Belt Dryers offer no potential for screening or cleaning of biomass material Fines particles can blind the belt, block airflow, cause the belt to jam Larger foreign bodies can cut plastic belts	No material screening Fines material usually is found in the channels under the drying floor which requires manual cleaning

Small fines collected in the sub-floor plenum of FlowDrya

Capital Costs vs Operating Costs: Full Economic Comparison

FlowDrya	Belt Dryer	On-Floor Dryer
Compact, few moving parts, fast onsite installation PulseWave™ agitation, low parasitic load Low electrical requirements, low maintenance costs Long-life design and low depreciation costs Most economic biomass dryer solution available	Large footprint Hundreds of mechanical moving parts increase capital outlay Added complexity = higher maintenance costs to maintain dryer More downtime and increased after-care requirements lead to higher operating costs	The cost of concrete and building materials for on-floor dryers has surged The cost of ready-mixed concrete has increased by over 30% in 2022 alone Capital costs of grain dryers have also increased Expensive labour, loader and telehandler costs Wasted heat energy and low performance efficiency

Concrete Products & Cement Price Index in UK (2017-2022)

FlowDrya, Compared: Summary Table

Feature	FlowDrya	Belt Dryer	On-Floor Dryer
Design Complexity	Low	High	Medium
Maintenance	Very low	High	Medium–High
Energy Use	Lowest	High	Medium–High
Material Agitation	Excellent	Poor	None
Footprint	Small	Large	Very large
Installation	Fast	Slow	Longest
Fire Risk	Very low	High	High
Hopper Capacity	Very high	Very low	N/A
Control Accuracy	Excellent	Medium	Poor
Fines Removal	Integrated	None	None

Stronga: Setting the Quality Standards

When compared to on-floor and belt drying systems, the business case for FlowDrya is compelling. User-friendly operation and minimal maintenance requirements make for a highly economic biomass drying solution. Today, FlowDrya is the basis for our success in a wide range of drying applications and sectors.

Stronga's aim is to continuously improve our biomass drying systems with respect to emission reduction and energy efficiency. We are proud of our decades worth of experience in designing and building biomass drying solutions and are justified in claiming that we are setting quality drying standards, worldwide.

Stronga's experienced technical team

* The knowledge we share is based on customer feedback. Figures included in this article are estimates and based on average FlowDrya models. Actual performance data can only be issued on a project-by-project basis depending on the model of dryer and other factors.

Discuss Your Drying Requirements

Description and specification of the wet material to be dried *

Wet basis bulk density of the material to be dried

Wet basis moisture % of the material to be dried

Target dry % moisture of the output material

Photos of the material (JPG or PNG, max 5MB each, up to 5 files) Please include a reference object in the photo, such as a pen or coin, so we can view the particle size. Maximum 5 files, 5MB each.

The m³ of material you would like to process per annum

The heat source is a key consideration in the overall drying process. Please give us as much information as possible about your preferred fuel type / energy source for creating the hot air for drying.

Your preferred energy source (if applicable)

If your project includes residual heat, please specify the amount and form

If there is no residual heat available, specify your preferred fuel type

The planned location of the dryer * Local conditions affect drying performance.

Please provide your contact details so we can get in touch with you regarding your enquiry.

First Name *

Last Name *

Company / Organisation

Email Address *

Phone Number

Country *

I agree that Stronga may use my details as described in the Terms and Conditions and Privacy Policy *