Processes and systems for producing renewable energy and fibers from cellulose-rich waste materials.

Abstract

Several embodiments provide a process for producing renewable biogas and cellulosic fibers from a cellulose-rich feedstock, comprising: obtaining a cellulose-rich feedstock with reduced impurity concentration and a length of less than 5 inches; feeding the cellulose-rich feedstock and water into a vacuum steam explosion tank to generate a first cellulose-rich intermediate stream; feeding the cellulose-rich intermediate stream into a secondary separation tank to remove residual impurities to generate a second cellulose-rich intermediate stream; feeding the second cellulose-rich intermediate stream into an enzymatic hydrolysis tank to convert the second cellulose-rich intermediate stream into low-viscosity cellulosic fibers containing cellulose oligomers; feeding the low-viscosity cellulosic fibers into an anaerobic digester to generate a biogas stream and residual fibers; optionally, recirculating the residual fibers to the enzymatic hydrolysis tank and / or anaerobic digester; and recovering some or all of the residual cellulose fibers from the solid stream as a byproduct.

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