Heating unit, heating method and application of sequencing batch direct thermal desorption repair system

Abstract

The invention relates to a heating unit, a heating method and application of a sequencing batch direct thermal desorption remediation system and belongs to the field of contaminated soil remediation, combustion nozzles are arranged on a motion path of soil at intervals, the soil is heated in a segmented mode, the fuel utilization efficiency is higher, the fuel consumption is low, the fuel gas amount is small, and the tail gas treatment load is small. And on the heating path, the soil is in direct contact with combustion gas flames, and the heat exchange efficiency is higher. Soil is driven by the disc to do circular motion, the materials are overturned by the rake plow, disturbance to the materials is very low, and raised dust is basically not generated. By changing the relative position of the soil guide plate on the annular sliding rail and controlling ascending and descending of the soil guide plate, uniform arrangement of the to-be-heated soil on the heating disc is achieved. The heating time of the materials on the heating disc can be prolonged infinitely in a sequencing batch type feeding, distributing and heating mode, and the thermal desorption treatment effect can be achieved by prolonging the heating period for the materials which are difficult to volatilize and desorb.

Description

technical field [0001] The invention belongs to the field of contaminated soil remediation, in particular to a heating unit, a heating method and an application of a sequencing batch type direct thermal desorption repairing system. Background technique [0002] At present, the thermal desorption treatment devices for contaminated soil, especially the contaminated soil that is difficult to treat by traditional remediation techniques such as polycyclic aromatic hydrocarbons, pesticides, and petroleum hydrocarbons, mainly include cement kilns, direct thermal desorption rotary kilns, and indirect thermal desorption rotary kilns. (or spiral), heating stack, heating box and other forms. [0003] Among them, the cement kiln mainly realizes the high-temperature degradation of pollutants in the high-temperature calcination stage by adding polluted soil or solid waste as raw materials to the raw materials during the cement production process. The cement kiln has high treatment effici...

AI Technical Summary

Problems solved by technology

In order to ensure that the soil has enough heated flue gas on the heating path to achieve heat exchange, the combustion power of the burner can only be increased, which leads to a further increase in energy consumption, and the amount of flue gas after combustion is larger and mixed with pollutants and dust Afterwards, the tail gas end treatment load will increase sharply, resulting in an increase in end treatment energy consumption, and the economy is poor

[0005] (2) Since the soil inside the rotary kiln turns up and down with the rotation of the kiln body, and the kiln head heater has a large amount of flue gas, mechanical agitation and gas blowing Under the dual action of sweeping, a large amount of dust will be generated, and the generated dust mixed with pollutants and water vapor will enter the back-end tail gas treatment device together, resulting in increased difficulty in the treatment of the tail gas treatment device, and the equipment design of the tail gas treatment device is complicated. The convergence raises higher requirements and other issues

In addition, because the soil is turned up and down all the time inside the kiln body, the soil cannot be in uniform contact with the flame, resulting in low heat utilization efficiency.

[0006] (3) The heating time of the soil in the rotary kiln is mainly controlled by the rotation speed of the kiln body and the inclination angle of the kiln body, which leads to the existence of the residence time of the soil in the kiln upper limit

In case of difficult-to-volatilize pollutants such as pesticides and polycyclic aromatic hydrocarbons, the residence time cannot be increased, and the remediation effect of contaminated soil can only be ensured by increasing the heating temperature and heating times, which increases the cost of treatment and will cause tail gas end treatment. Dramatic changes in working conditions simultaneously increase the load and energy consumption of the tail gas treatment section

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