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Sludge anaerobic-digestion method based on combined pretreatment of thermal hydrolysis and chemical tempering

An anaerobic digestion and thermal hydrolysis technology, which is applied in pyrolysis sludge treatment, dehydration/drying/thickening sludge treatment, biological sludge treatment, etc., can solve high energy consumption, difficult to achieve energy gain, and operating condition requirements Advanced problems, to achieve the effect of low energy consumption, harmless, and strong economic applicability

Active Publication Date: 2017-11-24
SOUTHEAST UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0005] Purpose of the invention: The present invention proposes a sludge anaerobic digestion based on combined pretreatment of thermal hydrolysis and chemical conditioning to address the problems of high operating conditions, high energy consumption, and difficulty in realizing energy gains in existing sludge treatment methods method

Method used

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  • Sludge anaerobic-digestion method based on combined pretreatment of thermal hydrolysis and chemical tempering
  • Sludge anaerobic-digestion method based on combined pretreatment of thermal hydrolysis and chemical tempering
  • Sludge anaerobic-digestion method based on combined pretreatment of thermal hydrolysis and chemical tempering

Examples

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Embodiment 1

[0029]Get 250g of dewatered sludge (moisture content 84%) from a sewage treatment plant in Nanjing and put it into a mixing tank, stir at a low speed, add 250g of tap water and recycled water to obtain 500g of sludge with a solid content of 8%. Then, add 1mol / L sodium hydroxide in the stirring tank until the pH meter in the tank shows that the pH value is 10, and let it stand for 20 hours. Then pump the alkali-pretreated sludge into a high-temperature and high-pressure reactor, and thermally hydrolyze it at 80°C for 120 minutes. After thermal hydrolysis, the sludge is cooled to 55°C through a heat exchanger, and the energy is recovered to In the thermal hydrolysis stage, enter the stirring tank again, add 1mol / L hydrochloric acid to make the sludge neutral, add 1mol / L acetic acid to make the pH of the sludge 4, and then add 1mol / L sodium hydroxide until the system is neutral sex. Before performing anaerobic digestion, add 4.5L of sludge to the 5L anaerobic digestion reactor (...

Embodiment 2

[0031] Take 105.26g of dewatered sludge (water content 81%) from a sewage treatment plant in Yixing and put it into a stirring tank, stir at a low speed, add 228.07g of tap water, and obtain 333.33g of sludge with a solid content of 6%. Then, add 5 mol / L calcium hydroxide in the stirring tank until the pH meter in the tank shows that the pH value is 11, and let it stand for 24 hours. Then pump the alkali-pretreated sludge into a high-temperature and high-pressure reactor, and thermally hydrolyze it at 117.9°C for 30 minutes. After thermal hydrolysis, the sludge is cooled to 50°C through a heat exchanger, and the energy is recovered to In the thermal hydrolysis stage, enter the stirring tank again, add 2mol / L nitric acid to make the sludge neutral, add 3mol / L citric acid to make the sludge pH value 5, and then add 2mol / L calcium hydroxide until the system becomes neutral. Before anaerobic digestion, add 4.67L of sludge to the 5L anaerobic digestion reactor (pH value is 7.4, al...

Embodiment 3

[0033] The remaining sludge (with a water content of 99%) was taken from a sewage treatment plant in Nanjing, and the solid content was 9% after centrifugal concentration. Get 250g of sludge with a solid content rate of 9% and carry out pretreatment in the stirring tank. First, add 10mol / L potassium hydroxide to the stirring tank until the pH meter in the tank shows that the pH value is 12, and let it stand for 30 hours. Then pump the alkali-pretreated sludge into a high-temperature and high-pressure reactor, and thermally hydrolyze it at 100°C for 240 minutes. After thermal hydrolysis, the sludge is cooled to 60°C through a heat exchanger, and the energy is recovered to In the thermal hydrolysis stage, enter the stirring tank again, add 5mol / L sulfuric acid to make the sludge neutral, add 6mol / L malic acid to make the sludge pH value 5, and then add 5mol / L potassium hydroxide until the system becomes neutral. Before anaerobic digestion, add 4.75L of sludge to the 5L anaerobi...

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Abstract

The invention discloses a sludge anaerobic-digestion method based on combined pretreatment of thermal hydrolysis and chemical tempering. The sludge anaerobic-digestion method comprises the following steps: (1) adding water into sludge to dilute or concentrate, adding an alkaline substance, stirring, adjusting pH value to be alkaline and then standing; (2) carrying out thermal hydrolysis reaction on the sludge obtained in the step (1), adding a first acid substance after hydrothermal reaction, stirring, adjusting the pH value to be neutral, then adding a second acid substance, stirring, adjusting the pH value to be acid, finally adding the alkaline substance, stirring and adjusting the pH value to be neutral; and (3) carrying out anaerobic-digestion treatment on the sludge obtained in the step (2). The sludge anaerobic-digestion method disclosed by the invention has the advantages that the gas producing rate of anaerobic digestion of the sludge can be obviously increased, the gas producing amount and the produced-methane content of anaerobic digestion of the sludge are increased, sludge stabilization and the system stability condition are good, the energy consumption is low, the economic applicability is strong, the application bottleneck of anaerobic digestion of the sludge is broken through, and the sludge anaerobic-digestion method can better realize harmless, recycling and reducing treatment for the sludge when being used for treating municipal sludge.

Description

technical field [0001] The invention belongs to the field of solid waste treatment, and in particular relates to a sludge anaerobic digestion method based on combined pretreatment of thermal hydrolysis and chemical conditioning. Background technique [0002] Ecological environment protection has become a national strategy, and the treatment and disposal of solid waste has gradually attracted people's attention, and sludge is one of the hot spots. Sludge treatment and disposal follow the three principles of solid waste technology policy, that is, harmless, volume reduction, and recycling. Among the treatment technologies, anaerobic digestion technology is a treatment technology that is more in line with the three principles. [0003] However, traditional municipal sludge anaerobic digestion has disadvantages such as slow reaction speed, low gas production, long residence time (30-40 days), and high energy consumption, which limits the popularization and application of anaero...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C02F11/04C02F11/10C02F11/14
CPCC02F11/04C02F11/10C02F11/14
Inventor 黄瑛余华平
Owner SOUTHEAST UNIV
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