Processed biomass pellets from organic-carbon-containing feedstock
View Patent ↗A renewable processed biomass pellet composition made with a pelletizing sub-system from a processed organic-carbon-containing feedstock made with a beneficiation sub-system is described. Renewable biomass feedstock passed through a beneficiation sub-system to reduce water content to below at least 20 wt % and water-soluble intracellular salt reduction of at least 60 % from that of unprocessed organic-carbon-containing feedstock on a dry basis. The processed feedstock is introduced into a pelletizing sub-system to result in renewable processed biomass pellets having an energy density of at least 17 MMBTU/ton (20 GJ/MT) a water content of less than 20 wt %, and water-soluble intracellular salt content that is decreased by at least 60 wt % on a dry basis for the processed organic-carbon-containing feedstock from that of the unprocessed organic-carbon-containing feedstock, and made with 40 % less energy than expended to make current biomass pellets.
1. A process of making processed biomass pellets, comprising:
inputting into a first or beneficiation sub-system a renewable unprocessed organic-carbon-containing feedstock that includes free water, intercellular water, intracellular water, intracellular water-soluble salts, and at least some plant cells comprising cell walls that include lignin, hemicellulose, and microfibrils within fibrils;
passing the unprocessed organic-carbon-containing feedstock through the first sub-system, a beneficiation sub-system process, to produce processed organic-carbon-containing feedstock having a water content of less than 20 wt % and a water soluble intracellular salt content that is reduced by at least 60 wt % on a dry basis from that of the unprocessed organic-carbon-containing feedstock; and
passing the processed organic-carbon-containing feedstock through a second sub-system, a pelletizing sub-system, to produce, in processed biomass pellets, a solid renewable fuel composition having an energy density of at least 17 MMBTU/ton (20GJ/MT) a water content of less than 10 wt % and water-soluble intracellular salt that is decreased by at least 60 wt % on a dry basis from that of the unprocessed organic-carbon-containing feedstock,
wherein passing the unprocessed organic-carbon-containing feedstock through the first sub-system further comprises:
exposing the unprocessed organic-carbon-containing feedstock to solvent heated to at least 135° C. under a pressure of at least 260 psig for a residence time of at least 15minutes;
removing the pressure so as to create porous feedstock in the plant cell walls; and
pressing the porous feedstock to produce organic-carbon-containing feedstock that has a water content of less than 20 wt % and a water-soluble intracellular salt content that is decreased by at least 60 wt % on a dry basis from that of unprocessed organic-carbon-containing feedstock, and
wherein passing the processed organic-carbon-containing feedstock through the second subsystem further comprises:
compressing the processed organic-carbon-containing feedstock so as to separate it into pellets with discrete units of mass having the longest length of at least 4.0 cm and a density of at least 0.6 grams/cubic centimeter; and
collecting an aggregate of processed biomass pellets.
2. The process of claim 1 wherein the pelletizing sub-system process, further comprises the step of heating the processed organic-carbon-containing feedstock to reduce its water content to less than 10% by weight.
3. The process of claim 1 wherein the pelletizing sub-system process steps of compressing and exposing the unprocessed organic-carbon-containing feedstock to heated solvent are done at the same time.
4. The process of claim 1 , wherein the solvent is heated to a temperature selected from at least 165° C. and at least 180° C.
5. The process of claim 1 , wherein the pressure is selected from at least 280 psig, at least 375 psig, and at least 640 psig.
6. The process of claim 1 , wherein the residence time is selected from at least 20 minutes and at least 30 minutes.
7. The process of claim 1 , wherein exposing the unprocessed organic-carbon-containing feedstock to solvent is performed without dissolving more than 25 percent of the lignin and hemicellulose.