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A sludge anaerobic digestion method based on combined pretreatment of thermal hydrolysis and chemical conditioning

A technology of anaerobic digestion and thermal hydrolysis, applied in pyrolysis sludge treatment, dewatering/drying/concentrating sludge treatment, biological sludge treatment, etc., which can solve the requirements of high energy consumption, difficulty in achieving energy gains and operating conditions. Advanced problems, to achieve the effect of low energy consumption, harmless, and strong economical applicability

Active Publication Date: 2020-01-07
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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  • A sludge anaerobic digestion method based on combined pretreatment of thermal hydrolysis and chemical conditioning
  • A sludge anaerobic digestion method based on combined pretreatment of thermal hydrolysis and chemical conditioning
  • A sludge anaerobic digestion method based on combined pretreatment of thermal hydrolysis and chemical conditioning

Examples

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Embodiment 1

[0029] Take 250 g of dewatered sludge (84% moisture content) from a sewage treatment plant in Nanjing and put it into a stirring tank, stir at low speed, add 250 g of mixed water of tap water and reused water, and obtain 500 g of sludge with a solid content of 8%. Then add 1mol / L sodium hydroxide to the stirring tank until the pH meter in the tank shows a pH value of 10, and let it stand for 20 hours. Then the alkali pretreated sludge is pumped into a high-temperature and high-pressure reactor, and thermally hydrolyzed at 80°C for 120 minutes. After thermally hydrolyzed, the sludge is cooled to 55°C through a heat exchanger, and the energy is recovered after heat exchange. In the thermal hydrolysis stage, enter the stirring tank, add 1mol / L hydrochloric acid to make the sludge neutral, add 1mol / L acetic acid to make the sludge pH 4, then add 1mol / L sodium hydroxide until the system is in the middle Sex. Before anaerobic digestion, 4.5L of sludge (pH 7.4, alkalinity (calculated...

Embodiment 2

[0031] Take 105.26g of dewatered sludge (water content of 81%) from a sewage treatment plant in Yixing and put it into a stirring tank, stir at low speed, and add 228.07g of tap water to obtain 333.33g of sludge with a solid content of 6%. Then add 5mol / L calcium hydroxide to the stirring tank until the pH meter in the tank shows a pH value of 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 thermally hydrolyzed, the sludge is cooled to 50°C through a heat exchanger, and the energy is recovered after heat exchange. At the thermal hydrolysis stage, enter the stirring tank, add 2mol / L nitric acid to make the sludge neutral, add 3mol / L citric acid to make the sludge pH 5, and then add 2mol / L calcium hydroxide until the system is neutral. Before anaerobic digestion, add 4.67L of sludge (pH 7.4, alkalinity (calculated as bicarbonate) 2800mg / L, ammo...

Embodiment 3

[0033] Take the remaining sludge from a sewage treatment plant in Nanjing (with a water content of 99%) and concentrate it with a solid content of 9%. Take 250g of sludge with a solid content of 9% in a stirred tank for pretreatment. First, add 10 mol / L potassium hydroxide to the stirred tank until the pH meter in the tank shows a pH of 12, and let it stand for 30 hours. Then the alkali pretreated sludge is pumped into a high-temperature and high-pressure reactor, and thermally hydrolyzed at 100°C for 240 minutes. After the thermally hydrolyzed sludge is cooled to 60°C through a heat exchanger, the energy is recovered after heat exchange. In the thermal hydrolysis stage, enter the stirring tank, add 5mol / L sulfuric acid to make the sludge neutral, add 6mol / L malic acid to make the sludge pH 5, and then add 5mol / L potassium hydroxide until the system is neutral. Before anaerobic digestion, add 4.75L of sludge (pH 7.4, alkalinity (calculated as bicarbonate) of 3000mg / L, and ammo...

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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 specifically relates to a sludge anaerobic digestion method based on the combined pretreatment of thermal hydrolysis and chemical conditioning. Background technique [0002] Eco-environmental protection has risen to become a national strategy, in which the treatment and disposal of solid waste has gradually attracted attention, and sludge is one of the hot spots. Sludge treatment and disposal follow the three principles of solid waste technology policy, namely harmlessness, reduction and resource utilization. Among the treatment technologies, anaerobic digestion technology is a treatment technology that complies with the three principles. [0003] However, the traditional anaerobic digestion of municipal sludge has disadvantages such as slow reaction speed, low gas production, long residence time (30-40 days), and high energy consumption, which limit the popularization and application of anaero...

Claims

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Application Information

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