Decarbonisation Technology November 2026 issue

HDO

Raw lignin

Separation Liquefaction Lignin bio-oil

Stabilisation Deoxygenation / HDO

Inorganic removal

Upgraded lignin-derived oil

Renery

Problem High O

Problem Unstable molecules

Problem Na/K/Ca/Mg

Problem Renery incompatibility

Problem Solid lignin

Solution Liquefaction

Solution Stabilisation

Solution HDO

Solution Contaminant removal

Solution Co-processing

Feed preparation

Renery integration

(from solid to stable, clean pumpable oil)

(from upgraded oil to valuable products)

Figure 3 Lignin pretreatment

Where could lignin fit in a refinery? After stabilisation and preliminary deoxygenation, the upgraded lignin bio-oil can potentially be integrated into an existing refinery topology. Depending on market demands, feed quality, and the specific configuration of the brownfield infrastructure, this intermediate can follow different processing routes. Two representative pathways discussed in the literature are catalytic cracking and deep hydroprocessing. Co-processing in the FCC One potential pathway for incorporating lignin bio-oil is routing a suitably pretreated stream to an FCC unit. In this case, phenolic and other oxygenated intermediates can undergo further catalytic conversion to aromatics and cycloalkanes. This route depends strongly on the chemistry and pore structure of the FCC catalyst. Y-zeolites and HZSM-5 additives provide acidic sites that can promote the conversion of suitable lignin-derived molecules. Depending on the reaction conditions and product distribution, the resulting aromatic fraction could contribute to petrochemical feedstocks, while cycloalkanes and other hydrocarbon products may contribute to the gasoline-range pool. The feasibility of this route, however, depends on achieving sufficient stabilisation and contaminant removal before the feed reaches the catalyst.

that the liquid’s flow characteristics remain suitable for pumping and handling. The second step focuses on reducing the oxygen content and removing inorganic impurities. This contaminant removal is critical because it strongly influences the bio-oil’s compatibility with downstream catalytic and separation infrastructure. The ultimate aim of this two-stage upgrading approach is to remove catalyst poisons and hydrogenate the lignin-derived feed sufficiently to approach the quality required for conventional “ After stabilisation and preliminary deoxygenation, the upgraded lignin bio-oil can potentially be integrated into an existing refinery topology ” petroleum fractions. Where technically appropriate, existing hydrodeoxygenation (HDO) infrastructure may offer an opportunity for integration rather than requiring entirely new production units. Literature studies have investigated HDO of lignin-derived oils using conventional hydrotreating catalysts, including NiMo/ γ -Al2 O 3, with substantial reductions in oxygen content reported under suitable operating conditions. The resulting stabilised intermediate can then be considered for further co-processing in primary conversion units such as FCC or hydrocracking, depending on its final properties and the refinery configuration ( Lv, ve diğerleri, 2022 ).

Deep hydroprocessing Alternatively, the bio-oil can be routed to