PROCESSES AND APPARATUS FOR MANAGING AND RECYCLING SULFUR DIOXIDE IN BIOREFINERIES

摘要

What is disclosed is a biorefining process and system including the steps of extracting, hydrolyzing, and/or digesting a lignocellulosic biomass feedstock, or a component thereof, with a liquid or vapor solution comprising reactant sulfur dioxide or a derivative thereof, to generate cellulose-rich solids and an intermediate liquid stream; combusting or gasifying a sulfur-containing fuel to generate heat and an exhaust gas stream comprising produced sulfur dioxide; contacting the exhaust gas stream with the intermediate liquid stream to dissolve the produced sulfur dioxide into the intermediate liquid stream; and then recycling the intermediate liquid stream to reuse the produced sulfur dioxide as the reactant sulfur dioxide. The sulfur-containing fuel may be sulfonated lignin generated by reaction of lignin (derived from the feedstock) with the reactant sulfur dioxide, resulting in a closed loop for sulfur dioxide in the biorefinery.

主权项

1. A biorefining process comprising:
(a) providing a lignocellulosic biomass feedstock; (b) extracting, hydrolyzing, and/or digesting said feedstock, or a component thereof, with a liquid or vapor solution comprising reactant sulfur dioxide or a derivative thereof, to generate cellulose-rich solids and an intermediate liquid stream; (c) combusting or gasifying a sulfur-containing fuel to generate heat and an exhaust gas stream comprising produced sulfur dioxide; (d) optionally removing at least a portion of hemicellulosic sugars and/or lignin, if present, from said intermediate liquid stream; (e) contacting at least a portion of said exhaust gas stream with said intermediate liquid stream to dissolve said produced sulfur dioxide into said intermediate liquid stream; and (f) recycling at least some of said intermediate liquid stream back to step (b) to reuse said produced sulfur dioxide as said reactant sulfur dioxide.