Sludge gas heat carrier graded low-temperature pyrolysis system and method

Abstract

The invention discloses a sludge gas heat carrier graded low-temperature pyrolysis system and method. The system comprises a stirring former and a distributor connected to the outlet end of the stirring former. The outlet end of the distributer is arranged over a porous metal belt, the conveying direction of the porous metal belt sequentially passes through a drying reactor, a pyrolysis reactor and a dry quenching reactor, and the tail end of the porous metal belt stretches out of the dry quenching reactor and is used for outputting semi-coke; part of the semi-coke is back-mixed, stirred withraw sludge and then formed, sludge particle layer distribution is carried out on the porous metal belt, by means of a gas heat carrier graded pyrolysis mode and in combination with the system processes such as dry method quenching, tar recovery and pyrolysis gas reuse, modularization of the sludge pyrolysis system is achieved, the tar dust content is reduced through multiple dust removal measures,the added value of products is increased, the energy consumption of sludge pyrolysis is reduced, water in the sludge is recycled, the amount of seriously-polluted pyrolysis phenolic wastewater is greatly reduced, and the economical efficiency of the process is remarkably improved.

Description

technical field [0001] The invention belongs to the technical field of sludge disposal, and in particular relates to a sludge gas heat carrier graded low-temperature pyrolysis system and method. Background technique [0002] With the increase of sewage treatment rate in our country year by year, the output of sludge enriched with more than 50% of heavy metals and more than 90% of pathogenic microorganisms in sewage is increasing. If it is not effectively disposed of, the degree of harm will be very serious. In recent years The state has issued a number of policies such as the "Water Pollution Prevention and Control Action Plan" (namely "Water Ten Measures"), emphasizing that sludge must be properly disposed of. Pyrolysis technology, that is, heating sludge under anaerobic or hypoxic conditions, and through the process of heat and mass transfer, pyrolysis gas, tar, and semi-coke are obtained. Compared with other disposal technologies, sludge pyrolysis technology has the adva...

AI Technical Summary

Problems solved by technology

[0003] Generally, the water content of dewatered sludge that needs to be disposed of in sewage plants is about 80%. If it is directly pyrolyzed, it will consume a lot of energy and produce a large amount of phenolic pyrolysis wastewater, causing serious pollution.

If the semi-coke is cooled by water spraying, water sealing, etc., it will also produce high-concentration phenol-containing wastewater that is difficult to dispose of

Some patented technologies use solid heat carrier and external thermal pyrolysis, which have problems such as uneven mass and heat transfer, large equipment wear, low thermal efficiency, small processing capacity, and long reaction time.

In addition, an important reason for restricting the industrialization of sludge pyrolysis technology is that the dust content in the tar is too high, which makes it difficult to use and seriously affects the economics of the process.

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