Concurrent Anaerobic Digestion and Fermentation of Lignocellulosic Feedstocks

A process for concurrent production of lignins and biogas from a lignocellulosic feedstock, the process comprising the steps of:

• pretreating the lignocellulosic feedstock to produce at least a solubilised liquid components stream comprising lignins and lignin-derived compounds, and an amorphous delignified solids output stream comprising cellulosic pulp;
• separating the solubilised liquid components stream and the amorphous solids output stream;
• further processing the solubilised liquid components stream to separate and recover therefrom at least lignins, lignin-derived compounds, and a semi-solid waste material;
• and
• anaerobically digesting the semi-solid waste material from the solubilized liquid components stream and the amorphous solids output stream to produce a biogas therefrom, wherein the anaerobic digestion comprises the steps of:
• first, liquefying the waste materials thereby producing a first liquid stream comprising monosaccharide sugars;
• second, acidifying the first liquid stream thereby producing a second liquid stream comprising organic acids;
• third, acetifying the second liquid stream thereby producing a third liquid stream comprising acetic acid;
• and
• fourth, microbially converting the acetic acid to a biogas mixture comprising at least methane and carbon dioxide.

A system for concurrent production of lignins, fuel alcohol, and biogas from a lignocellulosic feedstock, the system comprising:

• equipment configured for controllably receiving, commingling and processing therein a lignocellulosic feedstock and an organic solvent, and further configured to controllably provide at least a first output stream comprising amorphous de-lignified solids and a second output stream comprising a spent organic solvent comprising solubilized and suspended organic matter, said spent organic solvent containing therein lignins and lignin-derived compounds;
• equipment configured for controllably receiving and hydrolyzing therein said amorphous solids stream, and for controllably discharging a stream of hydrolysate therefrom;
• equipment configured for controllably separating said hydrolysate stream into at least a first hydrolysate stream and a second hydrolysate stream;
• equipment configured for controllably delivering said first hydrolysate stream into a fuel alcohol production system;
• and
• equipment configured for controllably delivering said second hydrolysate stream into an anaerobic digestion system.