Hydrofaction® Converts Lignocellulosic Biomass Like No Other Process

Lignocellulose, (the structural material in trees and many plants) is the most abundant renewable biomass on earth. It is comprised of Lignin, Cellulose and Hemicellulose. Different reaction mechanisms break down each component of Lignocellulose to produce biocrude. Within the group of Lignocellulosic materials, woody biomass is the largest sub-class, and wood waste/residues are the primary target feedstock of Steeper Energy.

Lignocellulosic residues are not edible and therefore their use to produce renewable biofuels will not form competition for food production, a key critique applicable to many other feedstock sources for renewable fuels.

Hydrothermal liquefaction (HTL) has attracted significant attention in recent years due to being a direct and more complete conversion pathway, with high carbon transfer efficiency (feedstock to oil), and high overall energy efficiency. Within wood, lignin contains 30-45% of the carbon content and 35-55% of the energy content. During Hydrofaction®, most of the organic carbon, including the lignin, is converted into biocrude oil.

Other biomass conversion processes such as cellulosic ethanol and anaerobic digestion do not convert lignin and hence cannot achieve the same high level of carbon and energy efficiency as HTL processes, and especially Hydrofaction®.

Hydrofaction® has many advantages, including:

  • The direct and more complete conversion of biomass into high quality biocrude
  • Feedstock drying is not required since an aqueous environment is used
  • Direct conversion to biocrude with few processing steps
  • Extensive heat recovery improving energy balance.
  • Low parasitic losses

 

Compared to other known HTL processes, Hydrofaction® maximizes conversion efficiency of forestry and agricultural feedstocks based on Steeper’s proprietary operating conditions and process control scheme. In Hydrofaction®, water-soluble organics are recovered, recycled, and further converted to biocrude. Compared to other thermochemical pathways and competing HTL technologies, Hydrofaction® has been demonstrated to achieve:

  • Higher overall conversion efficiency of biomass to biocrude, which maximizes advanced biofuel revenues
  • Lower biocrude oxygen content, which improves long-term product stability and reduces upgrading/hydroprocessing costs
  • Higher biocrude energy density, comparable to that of fossil crude oil, which facilitates co-processing and refinery integration

In competing bioenergy processes where lignin is not converted, a significant amount of the carbon and energy is not transferred into the final fuel product, creating inefficiencies. Although it is commonly accepted to offset these shortfalls by combusting the residual material for heat generation, or by marketing a biochar by-product, this clearly is not ideal considering the availability of higher efficiency conversion tools such as Hydrofaction®.

Hydrofaction® is also a more direct conversion route with higher overall energy efficiency than other thermochemical conversion pathways such as gasification followed by Fischer-Tropsch synthesis and fast pyrolysis followed by hydro-processing.

Steeper Energy has from the beginning been focused on woody biomass as the most promising candidate for Hydrofaction® processing driven by the following factors:

  • It is the most abundant biowaste stream in the world.
  • It is concentrated in sufficient volumes in specific locations to create handling efficiencies.
  • It is one of the few biomass feedstocks that allow production of renewable oil at a scale that’s relevant for the petroleum industry.
  • Less than 50% of a tree is utilized by current forestry industry practices. The other 50% is left as waste in the forest or in lumber yards, creating an opportunity for the deployment of Hydrofaction® technology.

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