Investigation into the mechanisms of pipeline transport of slurries of wheat straw and corn stover to supply a bio-refinery

• Pipeline transport of wheat straw and corn stover biomass slurries was studied.
• Biomass slurry was based on water as a slurry medium.
• Friction loss behaviour of slurry was experimentally investigated through pipeline.
• Particle features, slurry concentration, and velocity impact the friction loss.
• Fibrous biomass particles exhibited drag-reducing features above certain velocities.

Pipeline hydro-transport could be more economic approach than truck delivery for agricultural waste biomass to a bio-refinery for bio-fuel production. The transportation of slurries of wheat straw and corn stover agricultural waste biomass was investigated through a laboratory-scale closed-circuit pipeline facility. While the slurry was pumped, longitudinal friction loss was measured and analysed as a function of particle type and properties, slurry solid concentration, slurry flow rate, and measured carrier fluid viscosity. Irregularly shaped fibrous particles of agricultural waste biomass 2.0–9.0 mm in length and with aspect ratios of 2–7 exhibited drag-reducing features, e.g. a drag reduction of 33% for a slurry containing 40% [mass] of <3.2 mm corn stover particles. The role of particle dimensions and morphological features on slurry friction loss and drag-reducing behaviour was investigated. The influence of particle size distribution was recognised with broad size distributions producing lower frictional losses at higher flow rates. Above certain flow rates, larger-sized particles at lower solid concentrations produced the same drag ratio as smaller size particles at higher solid concentrations thus requiring lower pumping power. Slurries of wheat straw and corn stover particles affected pressure drop behaviour differently from conventional solid–liquid systems and showed decreasing pressure gradients with increasing solid concentration. The results obtained should assist the design and operation of agricultural waste biomass pipeline hydro-transport processes.