Sludge treatment method and treatment system

Abstract

The invention provides a sludge treatment method and treatment system. The treatment method comprises the following steps: discharging sludge into a sludge storage pond, and adding an anti-corrosion modifier and evenly mixing for storage; exporting sludge and delivering sludge into an agitator, and adding an alkaline modifier, evenly mixing and then ageing to obtain a sludge derived cement raw material; entering a vertical bushing dispersing and grading and drying furnace for dispersing, grading and drying, sorting out small-particular materials and large-particular materials, performing further grinding to the large-particular materials, then repeatedly circulating dispersing, grading, drying and grinding processes until all sludge become small--particular materials; and delivering the small-particular materials into a cement kiln tail smoke chamber for incineration. The sludge treatment method and the treatment system effectively overcome the negative influence factor during cooperative treatment of sludge during production in a cement kiln, forcibly conduct anti-corrosion modification to the sludge, reasonably treat waste gas and moisture in sludge, effectively control various effective elements of sludge carried in the cement kiln, avoid the situations influencing the cement kiln, and realizes the harmless treatment of sludge.

Description

Technical field [0001] The invention relates to the technical field of sludge treatment, in particular to a sludge treatment method and treatment system. Background technique [0002] Cement kiln co-processing of solid waste (including domestic waste and sludge) refers to waste disposal that achieves the decomposition, degradation, elimination, inertization and robustness of solid waste through high-temperature incineration and cement clinker mineralization and high-temperature sintering processes means. Cement kiln treatment has the technical advantages of wide application range, large consumption, strong adaptability to various wastes, large heat capacity, large thermal inertia and high heat transfer efficiency. The core of cement kiln co-processing technology for urban domestic sludge is to use domestic sludge, combustible components and ash materials in waste in the production process of cement, and apply appropriate technical solutions to make the sludge harmless and reduce...

AI Technical Summary

Problems solved by technology

[0006] ①. The moisture content of the sludge is high, and direct incineration in the cement kiln will destroy the stability of the cement kiln firing system

The potential moisture content of sludge is high, generally at 80%, and even higher than 90%. Because its macromolecular flocculation system is difficult to dehydrate mechanically, even dehydration will increase the burden of water treatment and easily cause secondary water pollution.

If it is directly incinerated in a cement kiln, a large amount of moisture in the incineration will make the sludge difficult to burn, and a large amount of water vapor generated during the combustion will increase the humidity of the cement kiln flue gas, reduce the system temperature, and bring great benefits to the safe operation of the cement kiln and energy saving and consumption reduction. Negative impact

Especially for the decomposed CaO in the decomposition kiln, it will easily absorb water, which will reduce the decomposition rate of CaO entering the kiln, thus affecting the output of the cement kiln

Therefore, in the sludge incineration process, most of them set up independent sludge incinerators to incinerate sludge, while the process of direct incineration in cement kilns is difficult to achieve

[0007] ②. The moisture content of the sludge is high, and adding it directly to the raw meal mill or coal mill will also cause difficulty in drying

Because sludge can be burned below 500°C, that is, after it enters the kiln system together with raw materials, the sludge will be burned in the third-stage drum, and it cannot be burned at a high temperature above 850°C to prevent the generation of dioxins

At the same time, the alkaline environment of the third-stage cylinder of the cement kiln is not very strong, because CaCO 3 It cannot be decomposed at about 500°C

Therefore, this method loses the favorable conditions for the harmless disposal of sludge by high-temperature alkaline incineration in cement kilns, and cannot realize the harmless disposal of sludge

[0009] ④. Sludge and coal are mixed and ground to make coal slime mixed fuel, which will reduce the absolute calorific value of pulverized coal entering the kiln, which is an insurmountable threshold for the cement industry, which already uses low calorific value coal.

For this reason, expensive combustion accelerants are added, and low-cost disposal cannot be achieved

[0010] ⑤. The direct drying process of urban domestic waste generally adopts the original rotary dryer system, which has low drying efficiency, high thermal efficiency and large investment

The patent mentions that a large amount of additional fuel is required for vaporization during the sludge vaporization process, which greatly increases the operating cost, does not actively take advantage of the advantages of the cement kiln, and has certain limitations

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