Sludge-crop straw joint disposal method based on fast pyrolysis

Abstract

The invention relates to the technical field of solid waste disposal, and discloses a sludge-crop straw joint disposal method based on fast pyrolysis. The sludge-crop straw joint disposal method based on fast pyrolysis comprises the following steps of 1) conveying the sun-dried crop straws to a pulverizer for pulverizing into straw powder, and then conveying the straw powder to a stirring chamber; 2) conveying dewatered sludge having the moisture content ranging from 70% to 85% into the stirring chamber to be sufficiently mixed with the straw powder to obtain a mixture; 3) conveying the mixture into a dryer for drying treatment, and then conveying the dried mixture into a pyrolysis reactor for fast pyrolysis treatment, and then outputting a high-temperature gas phase flow and high-temperature charcoal; 4) introducing the high-temperature gas phase flow into a cooling device for separation to obtain bio-oil and pyrolysis gas; 5) conveying partial high-temperature charcoal into the stirring chamber and sufficiently mixing the high-temperature charcoal with the dewatered sludge and the straw powder, and conveying the left high-temperature charcoal into a charcoal storage chamber for storage. According to the invention, the dewatered sludge and the straw powder are mixed and then together subjected to drying pyrolysis treatment; as a result, the sludge-crop straw joint disposal method based on fast pyrolysis is high in drying efficiency, low in energy consumption and high in bio-oil yield; the obtained charcoal is good in quality and large in value-added utilization space.

Description

technical field [0001] The invention relates to the technical field of solid waste treatment, in particular to a rapid pyrolysis-based joint treatment method for municipal sludge, industrial sludge and crop straws for reduction, harmlessness and resource utilization. Background technique [0002] A large amount of sludge will be generated during sewage or wastewater treatment. Taking urban sewage treatment plants as an example, every 10,000 m3 of sewage treatment will produce 5-10 tons of dewatered sludge (based on a moisture content of 80%). According to the requirements of my country's "Twelfth Five-Year Plan" National Urban Sewage Treatment and Reuse Facilities Construction Plan, by 2015, the scale of urban sewage treatment in my country will reach 208.05 million cubic meters per day. Based on this estimate, only urban sewage treatment plants in my country will 37.97-75.94 million tons of dewatered sludge will be produced every year; in addition to urban sewage treatment ...

AI Technical Summary

Problems solved by technology

[0009] (1) For some sludge with low organic matter content, the yield of bio-oil produced by pyrolysis and oilification is low, and the combustion of bio-oil products cannot meet the energy consumption demand of sludge drying, which affects the economy and applicability of the process ;

[0010] (2) Since the content of heavy metals in the biochar produced by sludge pyrolysis and oilification is about 1 times higher than that of the sludge itself, the content of heavy metals in some sludge biochars may not reach the level of sludge for agricultural use. Standards (for example, biochar produced by pyrolysis of low-quality sludge whose heavy metal content is close to the limit value of the sludge agricultural standard), the fertilizer utilization of sludge biochar is affected to a certain extent;

However, the utilization rate of straw in my country is not high, the utilization method is relatively extensive, the degree of resource utilization and commercialization is low, straw is thrown away randomly, and the phenomenon of disorderly open-air burning is serious, which not only causes waste of resources, but also causes a series of environmental problems

Images