Method for preparing organic fertilizer from urban and rural garbage by near-critical water technology

Abstract

The invention relates to a method for preparing organic fertilizer from urban and rural garbage by near-critical water technology, which comprises the following steps: sorting garbage, treating the organic substance raw materials, carrying out pyrolysis pretreatment, sending the raw materials into a pyrolysis kettle, adding oxidant, adding superheated water to submerge the surface of the raw materials, and adding magnesium oxide; continuing adding the oxidant until the pressure satisfies the requirement, and heating up the pyrolysis kettle, wherein the low temperature section is kept at the normal temperature of lower than 150 DEG C, the moderate temperature section is kept at the temperature of 150-200 DEG C and kept under the pressure, and the high temperature section is kept at the temperature of 200-230 DEG C and kept under the pressure; after the reaction finishes, relieving the pressure, discharging vapor and the pyrolysis liquid, drying the raw materials, and keeping the temperature to burst the raw materials in the kettle; removing impurities and heavy metals from the pyrolysis liquid for cycle use; and regulating the pH value of the pyrolyzed raw materials, pulverizing and selecting the organic fertilizer according to the particle sizes. Oxygen-enriched air is used as the oxidant, so that the raw materials are completely pyrolyzed, oxidized and decomposed, thereby avoiding secondary pollution; sufficient pyrolysis time can thoroughly kill pathogenic bacteria, viruses and parasites, thereby ensuring the safety of the fertilizer; the heavy metal removal processing technology is utilized to prevent the heavy metals in the product from damaging soil and crops; the reasonable pyrolysis temperature can completely degrade all the components in the organic substances; and the invention maximizes the resource utilization, thereby having the advantage of low production cost and reducing waste.

Description

technical field [0001] The invention relates to a treatment method for urban and rural waste, in particular to a method for preparing urban and rural waste into organic fertilizer by near-critical water technology. Background technique [0002] With the development of society today, people are faced with the problem of severe environmental protection and shortage of resources. In people's daily life, a large amount of garbage is produced every day, and garbage disposal has become a worldwide problem due to its huge quantity, complex composition, and environmental pollution. Traditional urban and rural waste treatment methods are mainly based on landfill, composting, and incineration; some hydrolysis processes such as acid, alkali, and enzyme catalysis are also used, but these methods and technologies do not make full use of biomass and waste, and are easy to damage the environment. cause secondary pollution. [0003] The known method of producing organic compound fertilizer...

AI Technical Summary

Problems solved by technology

These methods have the following problems in the treatment of garbage: 1. The industrial hydrolysis method with sulfuric acid as a catalyst has severe chemical reaction conditions and causes secondary environmental pollution; If it is not fully degraded, it will affect the absorption and fertilizer efficiency of plants

3. The heavy metals in the hydrolyzate are not treated during the reaction process, which not only affects the fertilizer efficiency but also brings harm to the soil and crops

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