A Novel Hydrothermal Treatment Process for Biogas and Bio-oil Production from Wastewater Sludge and Other Lignocellulosic Biomass Based Material
Tech ID: W-16-013
Sludge management is one of the most difficult and challenging tasks of wastewater treatment plants due to high water content and increasingly strict regulations for sludge reuse and disposal. Compared to conventional processes (aerobic and anaerobic respiration, digestion, incineration, pyrolysis etc.), hydrothermal liquefaction (HTL) has been shown to be a promising method for transforming wastewater sludge into value-added products, which include but are not limited to bio-crude oil, solid residue (bio-char) and biogas.
HTL is a thermo-chemical process where raw sludge of high water content can be heat treated directly in the absence of oxygen at 40-400oC under pressure (up to 25 MPa). Treatment of complex organic materials through this method improves the overall digestion rate for improved biogas production. The oils produced through these processes have been shown to have a much lower molecular weight than the oil produced from waste biomass processes.
The current Sludge-to-Oil and Sludge-to-Biogas technologies for energy recovery are based on hydrolysis and hydrothermal treatment methods. The limitation of these types of technologies are that they are restricted to small-batch laboratory reactor units. These processes are also energy-intensive and potentially capital-intensive as they require severe reaction conditions, including high pressure. Lastly, it is difficult to scale-up conversion for these activities, making the process inefficient.
Description of the Invention
Researchers at Western University have developed an efficient functional continuous system for the hydrothermal liquefaction (HTL) of combined wastewater sludge and other lignocellulosic biomass to yield bio-oil and bio-gas. It can treat the combined sludge and the lignocellulose of waste biomass at the same time. It can also co-produce biogas and bio-oil. The efficiency of this process is improved by the addition of inexpensive catalysts. This efficiency of operation results in a low carbon footprint and a more environmental friendly process.
The above described novel invented process has several significant advantages over the existing technologies:
- Co-production of biogas and bio-oil in parallel
- Treatment of two types of waste biomass at the same time (wastewater sludge and other waste lignocellulosic biomass)
- Enhanced economic process
- Improved bio-oil (lower molecular weight) product
- Significantly higher yield than existing bio-oil current processes
- Environmentally friendly process with a low carbon footprint
The process is ideal for thermal de-polymerization of wet-biomass into crude like oil. A highly environmentally friendly production for biogas and bio-oil production.
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