System and method for treating sludge and organic waste by cooperating with waste heat of cement kiln

Abstract

The invention relates to a system and a method for treating various organic wastes such as sludge, kitchen waste, kitchen garbage, biomass, excrement (comprising livestock), straws and the like. A pyrohydrolysis device is used for pretreating the sludge, so that the dewatering performance and the digestion performance of the sludge are improved, and the sludge is inactivated at high temperature; combined treatment is performed on various mixed organic wastes by adopting combined anaerobic digestion to generate biogas and biogas residues; biogas is used as fuel, power generation or natural gas purification, the biogas residues are dried by various waste heat of a cement kiln and then are pyrolyzed and gasified, and finally pyrolysis residues and pyrolysis gas are generated; and the pyrolysis residues are used as a cement kiln raw material, and the pyrolysis gas is used as a cement kiln fuel and plays a role in flue gas denitration. By means of the system and method, harmless, stable, reduction and recycling treatment of various mixed organic waste such as sludge, kitchen waste, kitchen garbage, biomass, excrement (comprising livestock), straws and the like is achieved.

Description

technical field [0001] The present invention relates to a system and method for cooperating with cement kiln waste heat to treat sludge and organic waste, in particular to a method of using sludge thermal hydrolysis pretreatment and pyrolysis gasification technology to cooperate with cement kiln waste heat to treat sludge and organic waste systems and methods. Background technique [0002] With the acceleration of my country's urbanization process and the rapid development of social economy, the output of various organic wastes such as sludge, kitchen waste, kitchen waste, biomass, manure (including livestock), and straw has increased year by year, which has a great impact on the ecological environment. The pressure is increasing. [0003] For example, sludge is a by-product of the sewage treatment process, mainly from the primary sedimentation tank and secondary sedimentation tank of the sewage treatment plant. Sludge not only contains a large amount of organic matter and ...

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Problems solved by technology

[0006] One of the existing technologies is to dehydrate the sludge after adding chemicals to achieve initial reduction, and then directly pull it to brick making, power plant or cement plant for incineration, but the sludge has not been pretreated, and it is directly dehydrated and reduced. The effect is average; and some have added a large amount of chemicals for the dehydration effect, which greatly reduces the reduction effect; the final sludge is incinerated, and the more water contained in it will affect the stability of the incineration process; none of the existing technologies The second is to continue to dry the dehydrated municipal sludge with an external heating source to achieve further dehydration. If the temperature of the drying heat source is high, it can also achieve initial stabilization and harmlessness. The dried sludge is then sent to brick making and power plants Or incineration in cement plants to achieve final reduction and harmlessness, but the drying process requires an external heat source, which increases energy consumption; in addition, the organic matter in sludge is a precious resource, and this technology only " One burns the matter", and the way of resource utilization is not high; the third existing technology is to carry out anaerobic digestion treatment of municipal sludge, and the generated biogas residue is subjected to subsequent treatment (including dehydration, drying, incineration, composting, etc.), biogas It is used to generate electricity, and the biogas slurry is treated and discharged after reaching the standard. However, the anaerobic digestion process needs to last for 20 to 30 days, and a large-volume digester is required as a container, which occupies a large area. It is difficult to find construction in the established cement plant The site requires high investment and complicated process; in addition, anaerobic digestion will produce a large amount of biogas residue and biogas slurry, and the biogas residue still contains some organic matter (30% to 60%), and the resource utilization is not complete. The moisture content is still high, and a large amount of heat resources are still required for drying and dehydration. In addition, the biogas slurry needs to be treated to meet the standard before it can be discharged.

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