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CN-107002100-B - Method and device for treating biomass and organic waste

CN107002100BCN 107002100 BCN107002100 BCN 107002100BCN-107002100-B

Abstract

The present invention provides a method for treating biomass material by fermentation, the method comprising pre-treating the biomass material by thermal hydrolysis and wet explosion, resulting in an intermediate product with a dry matter concentration above 25% and a temperature above 90 ℃, which is to be introduced into the fermentation, wherein a part of the content of a digestion tank for the fermentation is recycled and mixed with a part of the intermediate product from the pre-treatment.

Inventors

  • NILSEN PAAL JAHRE
  • HOLTE HANS RASMUS

Assignees

  • 坎比科技公司

Dates

Publication Date
20260505
Application Date
20151029
Priority Date
20141029

Claims (15)

  1. 1. A method for processing biomass material, comprising at least the steps of: pretreatment of the biomass material comprising the steps of: 1) Thermal hydrolysis at a temperature above 140 ℃, followed by 2) Wet explosion, yielding an intermediate product with a dry matter concentration higher than 25% and a temperature higher than 90 ℃ and a pH lower than 6, Subsequently fermenting said intermediate in a digester, and The method is further characterized in that the intermediate product is introduced into the digestion tank by mixing it into a portion of the contents of the digestion tank that is conveyed in a recirculation loop starting from the digestion tank, Wherein said mixing is performed before a mixture of said intermediate product and said portion of the contents of said digester enters said digester, wherein the pH of said portion of said digester is in the range of 7-8.5, and wherein the pH after said mixing and before said mixture enters said digester is above pH 6.
  2. 2. The process of claim 1, wherein the intermediate product has a temperature of greater than 100 ℃.
  3. 3. The process according to any one of claims 1 to 2, wherein the intermediate product has a pH value below 5.
  4. 4. The method of any one of claims 1-2, wherein the method further comprises wet oxidation, the wet oxidation being performed after the thermal hydrolysis and before the wet explosion.
  5. 5. The method according to any one of claims 1 to 2, wherein the part of the contents of the digestion tank is mixed with the intermediate product in such a way that at least 10 parts by volume of the contents of the digestion tank are mixed with one part of the intermediate product.
  6. 6. The method according to any one of claims 1 to 2, wherein a portion of the gas phase from the pretreatment is condensed by using a portion of the contents of the digestion tank as a cooling medium.
  7. 7. The method of claim 6, wherein the furfural in the condensed gas phase is separated by extraction.
  8. 8. The method of claim 6, wherein the volatile acid in the condensed gas phase is recycled to the digester.
  9. 9. The method of any one of claims 1 to 2, wherein the biomass material introduced into the method has a dry matter concentration of greater than 50 wt%.
  10. 10. The method according to any one of claims 1 to 2, wherein the biomass material introduced into the method is selected from the group consisting of straw, wood, fiber, bait, pulp and household waste.
  11. 11. The method of claim 10, wherein the biomass material introduced into the method is pulp.
  12. 12. The method according to any one of claims 1 to 2, wherein The thermal hydrolysis is carried out at a temperature above 140 ℃ and maintained for 5-30 minutes, followed by Wet explosions were performed by reducing the pressure from 5-35 bar to atmospheric pressure.
  13. 13. The method of claim 1, wherein the pH value after mixing the intermediate product with recycled fermentation product from the digester tank and before the mixture enters the fermenter is above pH 6.5.
  14. 14. The method of claim 1, wherein the volume ratio of the contents of the digestion tank mixed with the intermediate product is in the range of 3:1-30:1.
  15. 15. The method according to any one of claims 1 to 2, wherein the portion of the contents of the digestion tank is mixed with the intermediate product in such a way that at least 20 parts by volume of the contents of the digestion tank are mixed with one part of the intermediate product.

Description

Method and device for treating biomass and organic waste Technical Field The present invention relates to methods, processes and apparatus for treating materials that are primarily of organic origin, such as in the form of waste or biomass, wherein the content of sugars or the like of the treated material can be used for fermentation to one or more desired products. Background Municipal and industrial sludge and waste and other sources of waste products, mainly of organic origin, such as by-products of gardening, agriculture, forestry, wood industry, food processing industry etc., have received increasing attention for many years as possible starting materials for the production of CO 2 neutral fuels, such as bioethanol or biogas. Many different pretreatment methods have been described in the literature for biomass materials, where the contents of sugars and the like are more readily available. Most notable are strong and weak acid hydrolysis, wet explosion (steam explosion-STEX), wet Oxidation (WO), alkaline fiber explosion (ammonia fiber explosion-AFEX), and thermal hydrolysis (liquid hot water-LHW). Typically strong and weak acid hydrolysis is characterized by hemicellulose being hydrolyzed and dissolved, and availability of cellulose is increased for subsequent acid-based or enzymatic hydrolysis. When these types of hydrolysis are used, after separation of the insoluble and dissolved fractions, these fractions can furthermore be processed further by fermentation. Lightner (US 6.258.175) describes strong acid hydrolysis therein, wherein the possibility of reusing the acid used after precipitation with ethanol is also described. The main purpose of this process is to solubilize cellulose and hemicellulose for subsequent use in the production of ethanol, for example, by fermentation. There are several problems associated with acid hydrolysis of biomass. The material first needs to be separated into very fine particles (< 1 mm), which is extremely energy consuming. In addition, it is necessary to neutralize the treated material, which is typically done by adding CaCO 3 (limestone). This means that the consumption of chemicals in the process is high, while the neutralization process accumulates a large amount of hydrated calcium sulfate. Furthermore, the treated material from acid hydrolysis has an inhibitory effect on enzymatic hydrolysis and microbial fermentation compared to other forms of the treated material (see below). Finally, pumps, reactors, etc. are susceptible to corrosion due to acid catalyzed processes. The description of a wet explosion (STEX) dates back to 1928, when Mason developed a process for making cardboard (US 1.824.221 and 2.759.856). The STEX process involves thermal hydrolysis at high pressure, followed by release of the pressure in a so-called "flash action", wherein each fiber is exploded due to the substantial drop in pressure, hence the name wet (or steam) explosion. Such treatment methods were later developed further for the production of, for example, ethanol or paper (e.g., WO 98/27269). Partial dissolution (> 80%) of hemicellulose typically occurs in STEX and the cellulose is available for subsequent hydrolysis. STEX acts similarly to acid hydrolysis-however, the STEX process makes the process equipment less prone to wear and is not as harsh for use of chemicals and accumulation of waste. However, in STEX, considerable amounts of substances are still formed which inhibit possible subsequent fermentation processes (Palmqvist and Hahn-Hagerdal 2000), in particular when the material is liquefied beforehand with an acid (SO 2 or H 2SO4 (Martin et al, 2002)). Wet Oxidation (WO) has been developed to oxidize the organic waste fraction (US 2.690.425) and later improved to obtain hemicellulose solutions from lignocellulose-containing biomass and organic waste (see e.g. WO 00/14120). Wet oxidation involves a thermal process that adds an oxidizing agent, such as overpressure oxygen. In wet oxidation, hemicellulose is partially dissolved and a portion of the lignin present is oxidized, so that availability of cellulose increases. Generally, WO does not require additional process steps to remove the inhibitory substances. Alkaline Fiber Explosion (AFEX) is a process that combines steam explosion and addition of an alkaline catalyst. In conventional AFEX, biomass is liquefied in ammonia at moderate temperatures (50 ℃) followed by a momentary release of pressure (explosion). By this process, cellulose and lignin are modified, which makes the cellulose more reactive (available) while releasing hemicellulose. Thermal hydrolysis (LHW) is a process (typically 170 ℃ to 230 ℃) in which high dissolution of hemicellulose occurs simultaneously with partial dissolution of lignin and availability of cellulose is increased (for enzymatic hydrolysis). Sugarcane waste, which has not been separated beforehand and is pretreated with LHW, after addition of moderate amounts of enzymes, leads to a theoretic