Systems having digestion units with capability for loading cellulosic biomass under high pressure and associated methods for cellulosic biomass processing
AssigneeShell Oil Company
InventorsJoseph Broun Powell, Thomas Lamar Flowers
Life of this patent
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Abstract
When processing cellulosic biomass, it may be desirable for a digestion unit to operate without being fully depressurized for process efficiency purposes. A biomass conversion system can comprise a first digestion unit and a second digestion unit that are operatively connected to one another; a valve separating the first digestion unit from the second digestion unit; a fluid circulation loop establishing fluid communication between an outlet of the first digestion unit and an inlet of the second digestion unit; and a bypass line establishing fluid communication between an outlet of the second digestion unit and the fluid circulation loop.
Claims27
A method comprising:
- (a) providing biomass conversion system comprising:
- i. a first digestion unit and a second digestion unit that are operatively connected to one another;
- (b) at least partially digesting a first portion of cellulosic biomass in the second digestion unit, thereby forming a hydrolysate comprising soluble carbohydrates within a liquor phase;
- (c) providing pressure isolation between the first digestion unit and the second digestion unit;
- (d) after pressure isolation, at least partially depressurizing the first digestion unit and loading the first digestion unit with a second portion of cellulosic biomass while digestion continues in the second digestion unit;
- (e) re-pressurizing the first digestion unit to a pressure less than or equal to a pressure in the second digestion unit;
- (f) after said re-pressurization, equalizing the pressure between the first digestion unit and the second digestion unit;
- and
- (g) after said pressure equalization, transferring at least a portion of the cellulosic biomass from the first digestion unit to the second digestion unit.
A method comprising:
- at least partially digesting a cellulosic biomass contained in a first digestion unit and a second digestion unit to produce a hydrolysate comprising soluble carbohydrates in a liquor phase, the first digestion unit and the second digestion unit being operatively connected to one another;
- circulating the liquor phase from the first digestion unit to the second digestion unit through a fluid circulation loop establishing fluid communication between an outlet of the first digestion unit and an inlet of the second digestion unit;
- isolating the first digestion unit from the second digestion unit, the liquor phase continues to flow through the second digestion unit to the fluid circulation loop via a bypass line establishing fluid communication between an outlet of the second digestion unit and the fluid circulation loop;
- while hydrolysis continues in the second digestion unit, adding a cellulosic biomass to the first digestion unit and pressurizing the first digestion unit to a pressure that is less than or equal to a pressure in the second digestion unit;
- equalizing the pressure between the first digestion unit and the second digestion unit;
- and
- transferring at least a portion of the cellulosic biomass from the first digestion unit to the second digestion unit.
Dependencies are inferred from the claim text.