Decarbonisation Technology November 2026 issue

was qualified for integration into the Shell XTL Process, providing a key component of the technology package licensed by Shell. Yilkins’ integrated torrefaction solution Torrefaction involves heating organic material in the absence of oxygen

Yilkins setup

Product cooling

Torreed biomass

Pretreated biomass

Drying

Torrefaction

Pre-drying

Heat (hot air)

Water vapour condensation

Water vapour

Volatiles

Heat (ue gas)

Water vapour

Thermal oxidiser

Figure 3 Yilkins’ integrated torrefaction solution, showing how drying, heating, torrefaction, and densification can be combined with internal heat integration to upgrade biomass for downstream gasification

to improve properties such as energy density, grindability, water resistance and suitability for industrial processing. Yilkins’ technology combines drying, torrefaction and, where required, densification into an integrated biomass upgrading process. The process takes mechanically pretreated biomass through drying, heating, and torrefaction before producing either torrefied material or pellets for downstream use (see Figure 3 ). The first step is pre-drying in a swirling fluidised bed by a hot air stream, using waste heat recovered from the main drying process. Then the biomass is further dried in a second swirling fluidised bed to achieve the target moisture content (approximately 10 wt%) for efficient torrefaction. The water vapour effluent stream from the main drying process is condensed for heat recovery. The heat is used for pre-drying. The torrefaction step itself is split into two stages. First, biomass is rapidly heated in a swirling fluidised bed, which provides close temperature control. It then moves into the screw reactor torrefier, where it is held at the required temperature for sufficient time to decompose in a controlled way. This staged approach, with its close control of temperature and residence time, results in a homogeneous bio-coal product with reproducible qualities, while also supporting a linear approach to scale-up. A water spray is used to cool the torrefied product, stop the reactions, maintain product quality, and ensure safe handling of the product. Gases produced are discharged to the thermal oxidiser to produce a flue gas, which is used for (indirect) process heating. A key feature of the integrated design is

the way heat is managed across the process. This supports overall process efficiency while keeping flue gases separate from the biomass being treated. Yilkins’ technology aims to retain more of the carbon and hydrogen in the biomass, preserving the molecules needed for SAF production and supporting efficient fuel conversion per tonne of input. Yilkins’ swirling fluidised bed technology is developed to obtain a high level of flexibility in feedstock intake. A wide range of biomass types, ranging from clean wood to agricultural residues, fractions from municipal solid waste, and biomass pellets, have been processed ( Verma, et al, 2026 ). Typical operating conditions for the feedstock types evaluated by Yilkins fall within the design envelope of the equipment. Scalability Scalability is important for commercial BTL deployment. As Figure 4 shows, the technology has been scaled progressively from pilot plants to commercial-scale drying and torrefaction facilities. Two commercial-scale units have now been commissioned. In five years, Yilkins has achieved a tenfold scale-up without changing the core process concept. The same fundamental steps of swirl drying and torrefaction, direct product cooling, and heat integration have been retained throughout development. These are based on the company’s patented Swirling Fluidized Bed reactor technology combined with proven industrial equipment. A key outcome of the earlier scale-up phases is that the critical process fundamentals have already been demonstrated at commercial scale.