Bio-methanol

Bio-methanol from biomass residues is an advanced biofuel and produced:

• either by thermochemical conversion of biomass residues and waste streams into syngas,
• or by biological conversion into biogas, which is then reformed into syngas.

Feedstocks include lignocellulosic biomass such as forestry residues, agricultural residues (e.g. straw, husks, cobs), Municipal Solid Waste (MSW), and other waste streams.

The suitable pre-treatment and gasification technology depends on feedstock composition, moisture and ash content, as well as regional availability and logistics. The syngas clean-up scheme must be developed case by case, as it depends on both the feedstock characteristics and the gasification technology.

Downstream of the purified and conditioned syngas, methanol synthesis and distillation are standard, proven processes.

The process for bio-methanol production via gasification generally includes:

• Biomass reception, storage and handling
• Screening, size reduction and drying
• Gasification
• Tar reforming and syngas cooling with heat recovery
• Particulate removal and syngas scrubbing
• Acid gas removal and guard beds
• Water-gas shift for syngas conditioning
• Syngas compression
• Methanol synthesis loop
• Methanol distillation to fuel or chemical grade
• Storage and loading

As an alternative to gasification, biogas from anaerobic digestion is also a suitable input for bio-methanol production. In this case, the biogas is desulphurised and cleaned, and then converted into syngas by steam methane reforming (SMR) or autothermal reforming (ATR).