CN-116765105-B - Mercury-polluted soil treatment process and mercury-polluted soil treatment system

CN116765105BCN 116765105 BCN116765105 BCN 116765105BCN-116765105-B

Abstract

The invention provides a mercury contaminated soil treatment process and a mercury contaminated soil treatment system, wherein the mercury contaminated soil treatment process comprises the steps of adopting a thermal desorption heating process to treat mercury contaminated soil so as to thermally desorb mercury in the mercury contaminated soil in a gaseous form from the mercury contaminated soil and form mercury vapor; the method comprises the steps of cooling mercury vapor to convert at least part of mercury in the mercury vapor from a gaseous state to a liquid state and form liquid mercury, and carrying out a sedimentation process on the liquid mercury, wherein the liquid mercury is combined with a suspension material to form a suspension of mercury and is suspended in an upper layer of the liquid, and carrying out recovery treatment on the mercury in the suspension of mercury. By the technical scheme provided by the invention, the technical problem of poor mercury removal effect of the mercury contaminated soil treatment process in the prior art can be solved.

Inventors

XIAO CHAO
YANG ZHEN
WANG CONGMAO
YI GUIMI
ZHAO YUHAO
FU PENGCHENG
ZHANG WANQIU
WANG XIAOLI

Assignees

杰瑞环保科技有限公司

Dates

Publication Date: 20260508
Application Date: 20230609

Claims (10)

1. A mercury contaminated soil treatment process, comprising: treating the mercury contaminated soil by adopting a thermal desorption heating process so as to thermally desorb mercury in the mercury contaminated soil in a gaseous form from the mercury contaminated soil and form mercury vapor; Cooling the mercury vapor to cause at least a portion of the mercury in the mercury vapor to transition from a gaseous state to a liquid state and form liquid mercury; and carrying out a sedimentation process on the liquid mercury, combining the liquid mercury with a suspension material to form a mercury suspension, suspending the mercury suspension in an upper layer of the liquid, and recovering the mercury in the mercury suspension.
2. The mercury contaminated soil treatment process of claim 1, wherein the recovering of mercury from the mercury suspension comprises: heating the mercury suspension to evaporate mercury in the mercury suspension as a vapor; Condensing the vaporized gaseous mercury to obtain mercury product.
3. The mercury contaminated soil treatment process according to claim 1, wherein, after cooling the mercury vapor, A portion of the mercury vapor is maintained in a gaseous state to form a non-condensable gas; the mercury contaminated soil treatment process further comprises the following steps: adsorbing mercury in the non-condensable gas by using a mercury removal adsorbent, and reducing the mercury concentration in the non-condensable gas to a preset value; After the mercury concentration in the noncondensable gas is reduced to a preset value, introducing the noncondensable gas into a combustion chamber in the thermal desorption heating process for combustion and discharging.
4. A mercury contaminated soil treatment process according to claim 3, wherein prior to adsorbing mercury in said non-condensable gas with a mercury removal adsorbent, said mercury contaminated soil treatment process further comprises: performing gas-liquid separation on the non-condensable gas to remove liquid in the non-condensable gas, and/or, And dedusting the non-condensable gas to remove dust in the non-condensable gas.
5. The mercury contaminated soil treatment process according to claim 1, wherein in the sedimentation process, a bottom sludge is formed under the liquid, the mercury contaminated soil treatment process further comprising: carrying out dehydration treatment on the sediment, and detecting the mercury content of the dehydrated sediment; when the mercury content of the dehydrated bottom mud is smaller than a preset value, discharging the dehydrated bottom mud; And when the mercury content of the dehydrated sediment is greater than or equal to the preset value, treating the dehydrated sediment by adopting the thermal desorption heating process.
6. The mercury contaminated soil treatment process of claim 1, wherein in the sedimentation process, a bottom mud is formed below the liquid, the mercury contaminated soil treatment process further comprising: Separating water between the bottom mud and the mercury suspension, and cooling the separated water; And spraying and cooling the mercury vapor by utilizing the cooled water.
7. The mercury contaminated soil treatment process according to claim 1, wherein, The soil is treated by adopting a thermal desorption heating process, which comprises controlling the heating temperature in the thermal desorption heating process to be T 1 ,200℃≤T 1 ℃ less than or equal to 500 ℃, controlling the heating temperature in the thermal desorption heating process to be T, and/or controlling the heating temperature in the thermal desorption heating process to be T to be more than or equal to 20min and less than or equal to 60min, Cooling the mercury vapor includes cooling the mercury vapor to a temperature T 2 ,30℃≤T 2 < 50 ℃.
8. A mercury contaminated soil treatment system, adapted for use in the mercury contaminated soil treatment process of any one of claims 1 to 7, comprising: the thermal desorption structure (10) is used for carrying out thermal desorption heating treatment on the mercury contaminated soil to form mercury vapor; the cooling structure (20) is provided with an air inlet, a liquid outlet and a cooling cavity communicated with the air inlet and the liquid outlet, wherein the air inlet is used for introducing mercury vapor, and the mercury vapor forms liquid mercury after being cooled in the cooling cavity; the sedimentation separation structure (30) is provided with a liquid inlet, an overflow port and a sedimentation cavity communicated with the liquid inlet and the overflow port, wherein a suspension material is put into the sedimentation cavity, the liquid inlet is used for introducing the liquid mercury so as to enable the liquid mercury to be combined with the suspension material to form a mercury suspension, and the overflow port is used for discharging the mercury suspension; A mercury recovery structure (40), the mercury recovery structure (40) having a recovery inlet, the recovery inlet being in communication with the overflow, the suspension of mercury entering the mercury recovery structure (40) through the recovery inlet.
9. The mercury contaminated soil treatment system of claim 8, wherein the cooling structure (20) further has an air outlet in communication with the cooling chamber for exhausting non-condensable gases in the mercury vapor; The mercury contaminated soil treatment system further comprises: the non-condensable gas treatment structure (50), wherein the non-condensable gas treatment structure (50) comprises a gas-liquid separation structure and a mist capturing structure, the gas-liquid separation structure is used for performing gas-liquid separation on the non-condensable gas, and the mist capturing structure is used for taking out dust in the non-condensable gas; And the mercury adsorption structure (60) is communicated with the non-condensable gas treatment structure (50) so as to adsorb mercury on the gas treated by the non-condensable gas treatment structure (50) through the mercury adsorption structure (60).
10. The mercury contaminated soil treatment system of claim 8, wherein the sedimentation separation structure (30) further comprises a sludge discharge port located at a bottom of the sedimentation chamber, the sludge discharge port being in communication with the sedimentation chamber, the sludge discharge port being for discharging bottom sludge located at the bottom of the sedimentation chamber, the cooling structure (20) comprising a spray member mounted within the cooling chamber, the spray member spraying liquid for cooling the mercury vapor; The mercury contaminated soil treatment system further comprises: and the heat exchange inlet of the heat exchange structure (70) is used for introducing liquid between the mercury suspension and the bottom mud, and the heat exchange outlet of the heat exchange structure (70) is communicated with the spraying piece.

Description

Mercury-polluted soil treatment process and mercury-polluted soil treatment system Technical Field The invention relates to the technical field of mercury contaminated soil treatment, in particular to a mercury contaminated soil treatment process and a mercury contaminated soil treatment system. Background At present, the pollutants in the polluted soil in the prior art are mainly divided into heavy metal pollution and organic pollution, the heavy metal pollution soil can be treated by chemical leaching or solidifying and stabilizing technology, and the organic pollution soil can be treated by chemical leaching, chemical oxidation or thermal desorption and other modes. For mercury contaminated soil, although the mercury contaminated soil belongs to heavy metal pollution, mercury has certain volatility, and can be treated by using a thermal desorption method. The thermal desorption treatment of the mercury-containing polluted soil mainly adopts a heating mode to desorb mercury in the soil, mercury vapor generated by heating enters a gas treatment link, and the mercury is cooled or adsorbed in a gas treatment part, so that the removal of the mercury is realized. However, in the treatment process of the mercury contaminated soil by thermal desorption in the prior art, most of the mercury and water vapor are cooled from a gaseous state to a liquid state by adopting a cooling mode, because the specific gravity of mercury is higher than that of water, the cooled mercury can be settled to the bottom of the water and mixed with bottom sediment to form mercury-containing sediment, and if the partial sediment is dehydrated and returned to a thermal desorption process for treatment, the partial sediment still can be enriched into the sediment again, and the partial sediment is generally transported and treated as hazardous waste, so that mercury cannot be effectively removed from the whole treatment system. Disclosure of Invention The invention mainly aims to provide a mercury contaminated soil treatment process and a mercury contaminated soil treatment system, so as to solve the technical problem of poor mercury removal effect of the mercury contaminated soil treatment process in the prior art. In order to achieve the above object, according to one aspect of the present invention, there is provided a mercury contaminated soil treatment process comprising: treating the mercury contaminated soil by adopting a thermal desorption heating process so as to thermally desorb mercury in the mercury contaminated soil in a gaseous form from the mercury contaminated soil and form mercury vapor; Cooling the mercury vapor to cause at least a portion of the mercury in the mercury vapor to transition from a gaseous state to a liquid state and form liquid mercury; and (3) carrying out a sedimentation process on the liquid mercury, combining the liquid mercury with a suspension material to form a mercury suspension, suspending the mercury suspension in the upper layer of the liquid, and recovering the mercury in the mercury suspension. Further, the recovery treatment of mercury in the mercury suspension comprises: heating the mercury suspension to evaporate mercury in the mercury suspension as a vapor; Condensing the vaporized gaseous mercury to obtain mercury product. Further, after cooling the mercury vapor, a portion of the mercury vapor remains in a gaseous state to form a non-condensable gas, and the mercury contaminated soil treatment process further comprises: Adsorbing mercury in the noncondensable gas by using a mercury removal adsorbent, and reducing the concentration of mercury in the noncondensable gas to a preset value; After the mercury concentration in the noncondensable gas is reduced to a preset value, the noncondensable gas is introduced into a combustion chamber in a thermal desorption heating process for combustion and then discharged. Further, the mercury contaminated soil treatment process further comprises, prior to adsorbing mercury in the non-condensable gas with the mercury removal adsorbent: Performing gas-liquid separation on the non-condensable gas to remove liquid in the non-condensable gas, and/or, And dedusting the non-condensable gas to remove dust in the non-condensable gas. Further, in the sedimentation process, bottom mud is formed below the liquid, and the mercury contaminated soil treatment process further comprises: Dewatering the bottom mud, and detecting the mercury content of the dewatered bottom mud; Discharging the dehydrated sediment when the mercury content of the dehydrated sediment is smaller than a preset value; And when the mercury content of the dehydrated sediment is greater than or equal to a preset value, treating the dehydrated sediment by adopting a thermal desorption heating process. Further, in the sedimentation process, bottom mud is formed below the liquid, and the mercury contaminated soil treatment process further comprises: separating water between the bottom mud and the m