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CN-122012632-A - Technology for preparing biogas by recycling potato starch wastewater and waste residues

CN122012632ACN 122012632 ACN122012632 ACN 122012632ACN-122012632-A

Abstract

The application relates to the technical field of potato starch wastewater and waste residue treatment, in particular to a process for preparing biogas by recycling potato starch wastewater and waste residue. The method comprises the steps of collecting potato starch waste residues and waste water, crushing the potato starch waste residues, mixing the crushed potato starch waste residues and the waste water, regulating the solid content to 8-12% to obtain mixed feed liquid, carrying out heat treatment on the mixed feed liquid, cooling, adding a compound enzyme preparation, adding nitrogen to regulate the carbon nitrogen ratio to obtain a pretreated raw material, adding the pretreated raw material into an acidogenic phase reactor for hydrolysis and acidification, pumping the pretreated raw material into a methanogenic phase reactor for producing methane, collecting methane produced at the top of the methanogenic reactor by a gas collecting cover, purifying and storing the methane in a gas storage tank. The biogas preparation process provided by the application has the advantages that the yield of the obtained biogas is high, the content of methane in the unpurified biogas is high, and the subsequent purification is convenient.

Inventors

  • HE ZHICHENG
  • ZHAO JIANG
  • FAN XIHUI

Assignees

  • 甘肃省高原薯业有限公司

Dates

Publication Date
20260512
Application Date
20260305

Claims (9)

  1. 1. A process for preparing biogas by recycling potato starch wastewater and waste residues is characterized by comprising the following steps: S1, collecting potato starch waste residues and waste water, crushing the potato starch waste residues, mixing the crushed potato starch waste residues with the waste water, regulating the solid content to 8-12% to obtain mixed feed liquid, performing heat treatment on the mixed feed liquid, cooling, adding a compound enzyme preparation, and adding nitrogen to regulate the carbon-nitrogen ratio to obtain a pretreated raw material; S2, adding the pretreated raw materials into an acidogenic phase reactor for hydrolysis and acidification, pumping the pretreated raw materials into the methanogenic phase reactor for producing methane, collecting methane generated at the top of the methanogenic reactor by a gas collecting cover, purifying the methane, and storing the methane in a gas storage tank.
  2. 2. The process for preparing biogas by recycling potato starch waste water and waste residues according to claim 1, wherein the process is characterized in that the process comprises the steps of crushing until the particle size is less than or equal to 10mm.
  3. 3. The process for preparing biogas by recycling potato starch waste water and waste residues according to claim 1, wherein the mixing is carried out by mixing potato starch waste residues and waste water according to a mass ratio of 1-2:10-15.
  4. 4. The process for preparing biogas by recycling potato starch waste water and waste residues according to claim 1, wherein the heat treatment is carried out under the condition of heating to 60-70 ℃ for 30-60min.
  5. 5. The process for preparing biogas by recycling potato starch waste water and waste residues, which is characterized in that the composite enzyme preparation consists of alpha-amylase and cellulase, wherein the mass ratio of the alpha-amylase to the cellulase is 1:3-4.
  6. 6. The process for preparing biogas by recycling potato starch waste water and waste residues according to claim 1, wherein the nitrogen addition is used for adjusting the carbon-nitrogen ratio, and livestock manure or urea is added for adjusting the carbon-nitrogen ratio to 20-30:1.
  7. 7. The process for preparing biogas by recycling potato starch waste water and waste residues according to claim 1, wherein the conditions of hydrolysis and acidification are that the temperature is 30-35 ℃, the pH value is adjusted to 5.5-6.0, the stirring rotation speed is 20-30rpm, and the reaction time is 1.5-2.5 days.
  8. 8. The process for preparing biogas by recycling potato starch waste water and waste residues according to claim 1, wherein the methanogenic reactor is an internal circulation reactor, and the inoculation reactor volume is 40-45% of granular sludge or flocculent anaerobic sludge.
  9. 9. The process for preparing biogas by recycling potato starch waste water and waste residues, which is characterized in that the reaction condition for producing methane is that the temperature is 30-35 ℃, the pH value is regulated to 6.8-7.4, and the reaction time is 15-20 days.

Description

Technology for preparing biogas by recycling potato starch wastewater and waste residues Technical Field The application relates to the technical field of potato starch wastewater and waste residue treatment, in particular to a process for preparing biogas by recycling potato starch wastewater and waste residue. Background A large amount of high-concentration organic wastewater and solid waste residues are generated in the potato starch processing process, and the potato starch has high chemical oxygen demand, strong acidity and easy biodegradation, and causes serious environmental pollution if being improperly processed. The traditional treatment method, such as aerobic biological treatment, has high energy consumption and can not realize resource recovery, and the anaerobic digestion technology can convert the organic wastes into biogas, so that the energy recovery is realized, and the treatment method is a more sustainable treatment direction. However, conventional single-phase anaerobic digestion processes have significant limitations with respect to the characteristics of potato starch waste water and waste residues. First, the rate of hydrolysis of complex organics in the feedstock is slow, limiting overall gas production efficiency. Secondly, the waste is extremely easy to hydrolyze and acidify rapidly in the digestion process, so that a large amount of volatile fatty acid is accumulated in the reactor, the pH value of the system is caused to drop rapidly, the activity of methanogen is seriously inhibited or even poisoned, and the process is unstable or even rancidity and collapse are caused. Therefore, an integrated process capable of deeply strengthening hydrolysis and acid dissolution inhibition risks is developed, and the integrated process has important significance for efficient and stable energy utilization of potato starch wastewater and waste residues. Disclosure of Invention Aiming at the problems, the application aims to provide a process for preparing biogas by recycling potato starch wastewater and waste residues, which has the advantages of high biogas yield, high methane content in unpurified biogas and convenient subsequent purification. In order to achieve the above purpose, the application provides a process for preparing biogas by recycling potato starch wastewater and waste residues, which comprises the following steps: S1, collecting potato starch waste residues and waste water, crushing the potato starch waste residues, mixing the crushed potato starch waste residues with the waste water, regulating the solid content to 8-12% to obtain mixed feed liquid, performing heat treatment on the mixed feed liquid, cooling, adding a compound enzyme preparation, and adding nitrogen to regulate the carbon-nitrogen ratio to obtain a pretreated raw material; in the process, the potato starch waste residues are crushed, the specific surface area can be increased, subsequent hydrolysis is facilitated, the cellulose structure can be effectively damaged by heat treatment, more organic matters are dissolved, the subsequent hydrolysis rate is improved, the waste residue hydrolysis efficiency is pertinently improved by adding the compound enzyme preparation, starch packages are quickly opened by amylase, the cellulose attacks the fiber structure, the hydrolysis efficiency of substrates is improved, and the biogas yield is improved. S2, adding the pretreated raw materials into an acidogenic phase reactor for hydrolysis and acidification, pumping the pretreated raw materials into the methanogenic phase reactor for producing methane, collecting methane generated at the top of the methanogenic reactor by a gas collecting cover, purifying the methane, and storing the methane in a gas storage tank. In the process, the acid-producing phase and the methane-producing phase are separated, hydrolytic acidification bacteria and methane-producing bacteria are respectively placed in two independent reactors, an optimal growth environment is created for each hydrolytic acidification bacteria and methane-producing bacteria, under optimal conditions, the acid-producing phase can more rapidly and thoroughly convert complex organic matters into volatile fatty acids, and the methane-producing phase can efficiently and exclusively convert the volatile fatty acids into methane, so that the methane yield and the methane purity are improved. Further, the grinding is carried out until the grain diameter is less than or equal to 10mm. Further, the mixing is carried out, and the potato starch waste residue and the waste water are mixed according to the mass ratio of 1-2:10-15. Further, the heat treatment is carried out under the condition of heating to 60-70 ℃ for 30-60min. Further, the complex enzyme preparation consists of alpha-amylase and cellulase, wherein the mass ratio of the alpha-amylase to the cellulase is 1:3-4. Further, the nitrogen addition adjusts the carbon-nitrogen ratio, and livestock manure or urea is added