Method for drying sludge by residual heat from boiler fume

A boiler flue gas and sludge drying technology, which is applied in dehydration/drying/thickened sludge treatment, sludge treatment through temperature control, etc., can solve the problems of large energy consumption, cost increase, reduction and resource treatment Implementation and other issues to achieve the effect of low economic cost, lower moisture content, lower temperature

Active Publication Date: 2005-08-17
ZHEJIANG UNIV
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  • Summary
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AI Technical Summary

Problems solved by technology

Sludge drying is a necessary process to realize the harmless, reduction and resourceful treatment of sludge in sewage treatment plants. The sludge generated from sewage treatment plants is mechanically dehydrated, and the moisture content is generally between 75-85%. , in order to dry the sl...

Method used

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Examples

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Effect test

example 1

[0034] Example 1, Jiangsu Jiangyin produces about 80 tons of industrial wastewater and domestic sewage sludge with a moisture content of 70-80% per day. Using boiler flue gas at 150-200°C, the moisture content of the sludge is reduced to 15 after a two-stage drying process -20%, and form sludge granules with a particle size of 1-6 mm. The sludge pellets retain more than 90% of the calorific value of the original sludge and use it as an auxiliary fuel for the boiler. The calorific value produced per ton of dry sludge is equivalent to one-third of the calorific value of standard coal, which can save coal every day 7-8 tons.

example 2

[0035] Example 2, Jiangsu Jiangyin produces about 80 tons of industrial wastewater and domestic sewage sludge with a moisture content of 70-80% per day. Using boiler flue gas at 150-200°C, the moisture content of the sludge is reduced to 15 after a two-stage drying process -20%, and form sludge granules with a particle size of 1-6 mm. The hardness of the sludge pellets meets the requirements for firing lightweight energy-saving bricks. Using it as a raw material for firing lightweight energy-saving bricks saves 15-25% of clay resources and 10-15% of energy compared with ordinary fired bricks. Lightweight and energy-saving The compressive strength of bricks reaches the national standard (GB5101-85).

example 3

[0036] Example 3, Jiangyin, Jiangsu produces about 80 tons of industrial wastewater and domestic sewage sludge with a moisture content of 70-80% per day. Using the flue gas of a boiler at 150-200 ° C, after a two-stage drying process, the moisture content of the sludge is reduced to 15-20%, and form sludge pellets with a particle size of 1-6 mm. The hardness of the sludge pellets meets the requirements for the production of cement pressed products, and it is used as a raw material for the production of cement pressed products (sidewalk slab bricks, grass planting bricks, side stones and cement pressed bricks). Their compressive strength, flexural strength and frost resistance The indicators such as strength and strength can meet the national standard (GB8239-1997) and the national building materials industry standard (JC446-91).

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Abstract

The method of utilizing boiler fume afterheat in drying sludge is to dry sludge from sewage works at low temperature condition with boiler fume afterheat in a two-section or three-section process and to form hard sludge pellets one 1-6 mm size. The sludge pellets may be used as the auxiliary fuel for boiler and in baking light brick and cement product. The present invention has low cost and opens one way of utilizing waste in treating waste. The present invention results in high environment utility, economic utility and social utility.

Description

technical field [0001] The invention relates to a method for drying sludge by using waste heat of boiler flue gas. Background technique [0002] Urban domestic sewage and industrial wastewater are treated by sewage treatment plants and can only be discharged after reaching the national sewage discharge standards. This is an environmental engineering measure that must be carried out to protect the ecological environment. Urban domestic sewage and industrial wastewater enter the sewage treatment plant through the sewage pipe network system. During the purification process, most of the pollutants in the sewage are transferred to the sludge, which makes the sludge produced by the sewage treatment plant have a large amount. , and is rich in high-concentration pollutants and heavy metals. Therefore, if these sludges are not properly treated, they will cause serious secondary pollution to the environment. [0003] The urban sewage treatment system includes two parts: water treatme...

Claims

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Application Information

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IPC IPC(8): C02F11/12C02F11/18
Inventor 翁焕新苏闽华
Owner ZHEJIANG UNIV
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