A Fluidized Bed Type Chromium Slag Pyrolysis Harmless Technology

Abstract

The invention is a fluidized bed type chromium slag pyrolysis harmless process, which is characterized in that: the biomass and the chromium slag are put into the high temperature fluidized bed pyrolysis furnace respectively, and the biomass is rapidly melted and pyrolyzed in the process And release a large amount of pyrolysis gas to reduce Cr(VI). At the same time, the pyrolysis residual carbon adheres to the surface of the chromium slag during the fluidization process to protect the reduced Cr(III) in the chromium slag from secondary oxidation. The chromium slag also effectively catalyzes the pyrolysis gas generated to avoid the generation of a large amount of highly polluting tar gas. Compared with the traditional pyrolysis process, this process greatly shortens the residence time, and can generate energy tail gas with high calorific value at the same time, avoiding the treatment and disposal of tail gas.

Description

technical field [0001] The invention is a fluidized bed type chromium slag pyrolysis harmless process. Through process control, the Cr(VI) in the chromium slag can be efficiently reduced, and the reaction time can be greatly shortened. At the same time, the tail gas can be used as energy, saving energy. While saving energy, it avoids exhaust gas treatment. The invention belongs to the technical field of environmental protection. Background technique [0002] Chromium slag is a by-product emitted during the production of dichromate. Because it contains water-soluble Cr(VI), it is extremely toxic. If it is stacked in the open air without treatment, it will cause varying degrees of pollution to groundwater sources, rivers or sea areas, and seriously endanger human health and the growth of animals and plants. [0003] Generally speaking, the current detoxification methods for chromium slag (i.e. changing highly toxic Cr(VI) to Cr(III)) are divided into two categories: wet deto...

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Problems solved by technology

However, this process has many defects. On the one hand, the process adopts the rotary kiln process, and the material stays in the kiln for a long time, so the processing efficiency is low.

On the other hand, since the process mixes organic matter and chromium slag in the low temperature area, during the process of the two moving to the high temperature area, the organic matter in the sludge will continuously produce tar gas and enter the tail gas along the air flow, and the tar gas contains a large amount of such as Carcinogens such as cycloaromatic hydrocarbons are easily discharged in the form of PM2.5 during the cooling process, which is extremely harmful, so secondary treatment is required for the exhaust gas

In addition, the tar gas produced by the organic matter in this process is diluted by the high-temperature gas flow, resulting in a decrease in the concentration of reducing gases in the gas flow, and the reduction atmosphere is not strong, which reduces the reduction efficiency of Cr(VI)

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