Processing biomass
Methods and systems are described for processing cellulosic and lignocellulosic materials into useful intermediates and products, such as energy and fuels. For example, conveying systems and methods, such as highly efficient vibratory conveyors, are described for the processing of the cellulosic and lignocellulosic materials.
1. A method comprising:
depositing a controlled stream of a biomass material, in particulate form, on a trough of a vibratory conveyor having a cover, using a spreader, the biomass material covering only a portion of a width of the trough;
vibrating the vibratory conveyor, while conveying the biomass material a distance such that the biomass material spreads out to cover the entire width of the trough; and then
exposing the biomass material on the vibratory conveyor to ionizing radiation in the form of at least one scanning electron beam through at least one corresponding opening in the conveyor cover.
2. The method of claim 1 , further comprising comminuting the biomass prior to exposing the biomass to the ionizing radiation.
3. The method of claim 2 , wherein comminuting is selected from the group consisting of shearing, chopping, grinding, hammermilling and combinations thereof.
4. The method of claim 2 , wherein comminuting produces a biomass material with particles, and more than 80% of the particles have at least one dimension that is less than about 0.25 inches.
5. The method of claim 2 , wherein comminuting produces a biomass material with particles, and no more than 5% of the particles are less than 0.03 inches in their greatest dimension.
6. The method of claim 1 , wherein the biomass is irradiated with 10 to 200 Mrad of radiation.
7. The method of claim 1 , wherein the biomass is exposed to more than one dose of radiation utilizing multiple accelerating heads to expose the biomass to a plurality of scanning electron beams while the biomass is being conveyed on the vibratory conveyor, each scanning electron beam being delivered through a corresponding opening in the cover.
8. The method of claim 1 , wherein the biomass material comprises cellulosic or lignocellulosic material.
9. The method of claim 8 , wherein the cellulosic or lignocellulosic material comprises a lignocellulosic material selected from the group consisting of wood, paper, paper products, cotton, grasses, grain residues, bagasse, jute, hemp, flax, bamboo, sisal, abaca, corn cobs, corn stover, coconut hair, algae, seaweed, straw, wheat straw and mixtures thereof.
10. The method of claim 1 , wherein the opening in the cover includes a window foil that allows passage of the ionizing radiation through the window foil and onto the biomass material.
11. The method of claim 1 , wherein the biomass material is conveyed at a rate of at least about 1000 lb/hr.
12. The method of claim 1 , wherein the spreader comprises a drop spreader.
13. The method of claim 1 , wherein the energy of the electron beam is from about 0.3 to 2 MeV.
14. The method of claim 1 , wherein the vibratory conveyor conveys the biomass material at an average speed of from about 3 to 100 ft/min.