Methods of biomass pretreatment
AssigneeThe Texas A&M University System
InventorsMark T. Holtzapple, Richard R. Davison
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Abstract
The invention is directed to methods for the pretreatment of a lignocellulose-containing biomass. Pretreatment comprises the addition of calcium hydroxide and water to the biomass to form a mixture, and subjecting the mixture to relatively high temperatures for a period of time sufficient to render the biomass amenable to digestion. The pretreated biomass is digested to produce useful products such as feedstocks, fuels, and compounds including fatty acids, sugars, ketones and alcohols. Alternatively, the pretreatment process includes the addition of an oxidizing agent, selected from the group consisting of oxygen and oxygen-containing gasses, to the mixture under pressure. The invention is also directed to a method for the recovery of calcium from the pretreated biomass.
Claims37
A method for pretreating a lignocellulose-containing biomass comprising the steps of adding calcium oxide or hydroxide and water and an oxidizing agent to the biomass to form a mixture;
- and pretreating the biomass for oxidizing lignin without degrading the lignocellulose by maintaining the mixture at greater than ambient temperature, but less than 100.degree. C. for a period of less than about 36 hours, so that the pretreated biomass contains a weight of glucose that is susceptible to hydrolysis that is greater than about 75% by weight of the total glucose present in the biomass before pretreatment.
A method for pretreating a lignocellulose-containing biomass comprising the steps of adding calcium oxide or hydroxide and water and an oxidizing agent, selected from the group consisting of oxygen and oxygen-containing gasses, to the biomass to form a mixture;
- pretreating the biomass for oxidizing lignin without degrading the lignocellulose by maintaining the mixture at greater than ambient temperature, but less than 100.degree. C. for a period of less than about 36 hours, so that the pretreated biomass contains a weight of glucose that is susceptible to hydrolysis that is greater than about 75% by weight of the total glucose present in the biomass before pretreatment;
- and hydrolyzing the pretreated biomass.
A method for recovering calcium from a biomass pretreatment process comprising:
- a) pretreating the biomass for oxidizing lignin without degrading the lignocellulose by adding calcium oxide or hydroxide and water and an oxidizing agent to the biomass to form a mixture and maintaining the mixture at greater than ambient temperature, but less than 100.degree. C. for a period of less than about 36 hours, so that the pretreated biomass contains a weight of glucose that is susceptible to hydrolysis that is greater than about 75% by weight of the total glucose present in the biomass before pretreatment;
- b) carbonating the pretreated mixture or a liquid portion thereof to precipitate calcium carbonate or bicarbonate;
- and
- c) recovering the precipitated calcium carbonate or bicarbonate.
A method for recovering calcium from a biomass pretreatment process comprising:
- a) pretreating the biomass for oxidizing lignin without degrading the lignocellulose by adding calcium oxide or hydroxide and water and an oxidizing agent, selected from the group consisting of oxygen and oxygen-containing gasses, to the biomass to form a mixture and maintaining the mixture at greater than ambient temperature, but less than 100.degree. C. for a period of less than about 36 hours, so that the pretreated biomass contains a weight of glucose that is susceptible to hydrolysis that is greater than about 75% by weight of the total glucose present in the biomass before pretreatment;
- b) adding a carbonating agent to the pretreated mixture or a liquid portion thereof to form calcium carbonate or bicarbonate;
- c) heating the calcium carbonate or bicarbonate to form calcium oxide;
- and recovering the calcium oxide.
Dependencies are inferred from the claim text.