Whilst sawmills, forestry owners and tree surgeons primarily focus on the production of pulp, paper, sawn timber for building and other wood-based products, there are opportunities to optimise profitable outcomes from directing surplus timber residues towards green energy production.

FlowDrya is the market-leading drying solution from Stronga which enables sawmills to direct residual woody by-products and residual/low-cost heat towards profitable outcomes. Many sawmills already have spare boiler capacity on-site for kiln drying wood; or have wood-gas power plants producing electricity and heat. Spare heat from either of these operations can be used for drying wood chips in the FlowDrya, as is demonstrated in the graphic below. Read on to learn more about the potential high value in recycling scrap wood for circular energy production.

With wood biofuel in consistently high demand across the globe, there is a big opportunity for modern sawmills to generate significant profits from transforming wet timber residues into increasingly valuable, dry chip.

Drying woodchip fuel locks in high calorific value, allowing sawmills to sell the valuable dry output in local markets to commercial and residential boiler owners, poultry farmers and non-fossil fuel users. These are highly desirable sales avenues for clients; selling the dry woodchip leads to even more profitable business from a product that will always be in demand.

Many sawmills that approach Stronga, particularly the smaller-scale ones, see more potential in the energy market over their familiar sawmill market. FlowDrya equipment enables an entry-point to the energy sector by reliably drying wood fuel to increase calorific value while reducing weight, transportation costs and storage risks (moulding).

Since its inception, FlowDrya equipment has been particularly well-proven with various woody fractions. Wet wood can disintegrate over time and become unusable in production industries; this can encourage landfill dumping along with its associated costs. Drying allows clients to completely avoid waste wood to landfill. What’s more, utilising waste wood by-products allows sawmills to qualify for environmental grants aimed at reducing CO₂ emissions and increasing carbon capture (biochar).

One potential sales avenue for sawmills is to sell dried biomass output as a fuel to local energy sites and residential end-users. With increasing uncertainty surrounding the cost and supply of fossil fuels in global energy markets, producing local biomass fuel on-site allows sawmills to contribute towards improved local energy independence with improved local security and cost stability. A key benefit of drying wood fuel is that it is a more renewable source of heat when compared to alterative options. The options available to sawmill owners include:
(1) To export the dry biomass fuel to biomass power plants for thermal decomposition and combined heat and power (CHP);
(2) For on-site utilisation as a biomass boiler fuel to power engines, heat buildings, produce on-site electricity and more;
(3) For biochar production and carbon credit sale. Biochar can be used or sold as a soil improver and carbon capture resource.

In an age where renewable energy is increasingly preferred and highly valued, don’t delay contacting Stronga to progress your woodchip drying project.

Fresh, green woody by-products retain high amounts of water – typically up to 50-60% depending on location, wood species, seasoning, climate and so on. The optimum moisture level for the fuel depends on boiler type and specification. Matching fuel supply with the boiler specification is extremely important for boiler efficiency, maintenance and output – typically, boilers require 10% moisture content for optimal outcomes. Using a biomass wood fuel with too high a moisture content for the boiler causes a number of operational issues, including; low thermal output, increased emissions from the flue, significantly increased maintenance and lower reliability with more breakdowns.

Drying biomass using Stronga’s continuous drying solutions is an essential step in profitable woodchip fuel supply business. Using wet biomass in wood gas power plants increases the emission of harmful volatile organic compounds which are damaging for both the environment and human health. The graph below indicates that a higher wood fuel moisture content directly increases exhaust gas emissions.

One potential avenue for sawmills is to invest in wood pyrolysis to generate biochar, biogas, bio-oil, heat and electricity. The graphic below visualises the inputs and outputs of the pyrolysis reactor process, specifically, while highlighting the important role of FlowDrya and Heatex equipment in achieving optimum outcomes. Notice how spare heat from the pyrolysis reactor can be utilised by the woodchip dryer as part of a circular process.

Biochar, an output of pyrolysis, is an excellent soil improver which is formed via the thermal decomposition of biomass in an oxygen-limited environment. As long as the input fuel is dry, the production emissions and added energy required to create biochar via pyrolysis are minimal – especially when using residual heat as part of a circular energy economy.

Biochar is considered carbon-negative and can be sold for its soil improving, carbon sequestration, moisture retention and yield-boosting qualities. Biochar’s carbon sequestration qualities mean producers can sell their “carbon credits” to companies using greenhouse gases and fossil fuels, where they can offset harmful GHG emissions. For more information on this process, take a look at our article, ‘Drying Biomass for Biochar’, under ‘Know How’ on the Stronga website.

Another option for sawmills is to invest in wood gasification which differs from the pyrolysis process in that it involves the conversion of biomass into gas, whereas pyrolysis involves biomass to liquid and solid products. In wood gasification, biomass is heated to produce syngas which can be used in a cogeneration engine to produce electricity and heat.

Drying wood fuel increases CHP opportunities. Electrical output from gasification can be used to run small-scale on-site equipment or, alternatively, sold to the grid while residual heat can be used in the dryer. The graphic below visualises the wood-gas opportunities available to sawmills who, by becoming energy producers, rely less on grid energy supply where prices can be unpredictable. For more information on gasification, refer to our recent ‘Drying Biomass for Gasification’ article.

Stronga have been manufacturing premium-level wood chip drying systems for many decades now. Our experienced team have the know-how to design class-leading solutions for sawmills of all scales. Local climate, moisture content and wood species all have a significant impact on drying and energy production. Contact Stronga’s technical team to receive expert advice on drying woodchips. Discover the key benefits of FlowDrya and Heatex equipment:

- FlowDrya has simple and reliable design with no belts, chains or sprockets, allowing for lower operating costs, minimal maintenance and superb service life.
- The hydraulic PulseWave™ moving floor system naturally agitates the biomass material at a set point depth often in the range of 300mm-500mm. PulseWave™ avoids the needs for ancillary mixing systems which are common (and also ineffective) in belt dryers.
- The DryStation™ HMI allows operators to control strokes per hour to achieve the target moisture content and throughput of the woody biomass. This ensures the output material is optimised for the pyrolysis reactor or wood gasifier.

- FlowDrya is fully insulated all-around, reducing heat loss and encouraging excellent thermal efficiency.
- FlowDrya and Heatex have been proven to operate effectively for over 8,000 hours a year. However, FlowDrya’s stop-start system ensures the machine is not actually “live” for all of these hours; this significantly extends the service life of key components.
- FlowDrya has a large hopper capacity with extension sides available, if required (see image). This reduces labour costs compared to belt dryers which typically have very small loading hoppers.
- As sawmills are all-too-aware, fire risks are rife in wood production industries. FlowDrya’s stop-start system, low-temperature drying and lack of moving parts mean fire-risks are extremely low.

Investing in FlowDrya wood chip drying equipment empowers sawmills to repurpose wet woodchip by-products into a valuable income stream. Choosing FlowDrya provides you with an extremely well-proven, highly reliable woodchip dryer for producing saleable output while fully utilising by-products and providing a wonderful return on the investment.

Stronga has decades worth of experience in drying woodchips of various grades, enquiring gives you access to this knowledge for free - info@stronga.co.uk.