Mercury removal system suitable for flue gas washing wastewater

Abstract

The utility model belongs to the technical field of mercury removal of wastewater, and particularly relates to a mercury removal system suitable for flue gas washing wastewater, which comprises a PH (potential of hydrogen) adjusting area, a mercury removal reaction area, a coagulation area, a flocculation area, a settling area, a sand filter tank, a carbon filter tank, a resin tank and a wastewater inlet arranged on the PH adjusting area. The settling zone, the sand filter tank, the carbon filter tank and the resin tank are connected through pipelines, a chemical precipitation method, an adsorption method and an ion exchange method are integrated into one system, most of inorganic mercury and elemental mercury are removed through a sulfide precipitation method, then organic mercury is removed through an activated carbon adsorption process, and the mercury removal efficiency is improved. Finally, residual inorganic mercury is removed through the principle of ion exchange with functional groups in the mercury removal resin, both organic mercury and inorganic mercury in the wastewater can be effectively removed, and the total mercury concentration in effluent is stably lower than 5 micrograms per liter. The system is small in occupied area, convenient to install, long in service life and low in operation cost.

Description

TECHNICAL FIELD

[0001] The utility model belongs to wastewater mercury removal technical field, concretely relates to a mercury removal system suitable for flue gas washing wastewater. BACKGROUND

[0002] Mercury treatment in wastewater is an important environmental problem because mercury is a heavy metal with high toxicity and bioaccumulation, causing serious harm to human health and the ecological environment. For mercury treatment in wastewater, various technologies and methods have been researched and applied, mainly including chemical precipitation, adsorption, ion exchange, etc. Domestic flue gas washing wastewater mostly uses chemical precipitation, generally using a combination of "chemical precipitation + ultrafiltration + nanofiltration" to ensure that the effluent quality meets the standard. A precipitating agent is added to the wastewater to react with mercury to form insoluble mercury sulfide, a flocculating agent is added to precipitate the insoluble mercury sulfide, and a complexing inhibitor is added to increase the precipitation effect, and further filtration and separation are carried out through ultrafiltration and nanofiltration devices to ensure that the discharge meets the standard. This treatment method can effectively remove inorganic mercury and elemental mercury, but the removal effect of organic mercury is not ideal, and the effluent quality completely depends on the mercury removal efficiency of precipitation, which cannot guarantee that the effluent meets the standard. SUMMARY

[0003] To solve the problems raised in the background art, the utility model provides a mercury removal system suitable for flue gas washing wastewater, which comprises a PH adjusting zone, a mercury removal reaction zone, a coagulation zone, a flocculation zone, a precipitation zone, a sand filter tank, a carbon filter tank, and a resin tank, and further comprises a wastewater inlet provided on the PH adjusting zone, and the precipitation zone, the sand filter tank, the carbon filter tank, and the resin tank are connected through pipelines.

[0004] As a mercury removal system suitable for flue gas washing wastewater according to the utility model, preferably, quartz sand is added to the inside of the sand filter tank to intercept suspended solids in the wastewater.

[0005] As a mercury removal system suitable for flue gas washing wastewater according to the utility model, preferably, activated carbon is added to the inside of the carbon filter tank to adsorb organic mercury in the wastewater and further intercept suspended solids.

[0006] As a mercury removal system suitable for flue gas washing wastewater according to the utility model, preferably, mercury removal resin is added to the inside of the resin tank to adsorb the remaining inorganic mercury in the wastewater.

[0007] As a mercury removal system suitable for flue gas washing wastewater according to the utility model, preferably, a water outlet is provided at the bottom end of the resin tank.

[0008] As a mercury removal system suitable for flue gas washing wastewater according to the utility model, preferably, a coagulant is added to the inside of the coagulation zone to make mercury sulfide gather together to form flocs.

[0009] As the utility model discloses a kind of mercury removal systems suitable for flue gas washing wastewater, preferably, the inside of flocculation zone is added flocculating agent to make floc constantly larger, and settle.

[0010] Compared with prior art, the beneficial effects of the utility model are:

[0011] Chemical precipitation method, adsorption method and ion exchange method are integrated into a system, most of inorganic mercury and elemental mercury are removed by sulfide precipitation method first, organic mercury is removed by activated carbon adsorption process, and finally the remaining inorganic mercury is removed by the principle of ion exchange with functional groups in mercury removal resin, organic mercury and inorganic mercury in wastewater can be effectively removed, and the total mercury concentration in effluent is stably lower than 5 μg / L. The system has small floor area, convenient installation, long service life and low operating cost. BRIEF DESCRIPTION OF DRAWINGS

[0012] The accompanying drawings are used to provide further understanding of the utility model, and constitute a part of the specification, and are used to explain the utility model together with embodiments of the utility model, and do not constitute limitation on the utility model. In the drawings:

[0013] Figure 1 It is the structural schematic diagram of the utility model;

[0014] In the drawings:

[0015] Wastewater inlet; 2, PH adjusting area; 3, mercury removal reaction zone; 4, coagulation zone; 5, flocculation zone; 6, sedimentation zone; 7, sand filter tank; 8, quartz sand; 9, carbon filter tank; 10, activated carbon; 11, resin tank; 12, mercury removal resin; 13, outlet. DETAILED DESCRIPTION

[0016] The technical solutions in the embodiments of the utility model will be clearly and completely described below in conjunction with the drawings in the embodiments of the utility model, and obviously, the described embodiments are only part of the embodiments of the utility model, not all the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by those skilled in the art without creative labor belong to the scope of protection of the utility model. EMBODIMENT

[0017] As Figure 1 Indicated;

[0018] A kind of mercury removal systems suitable for flue gas washing wastewater, including PH adjusting area 2, mercury removal reaction zone 3, coagulation zone 4, flocculation zone 5, sedimentation zone 6, sand filter tank 7, carbon filter tank 9, resin tank 11.

[0019] In this embodiment: to solve the technical problems existing in the prior art, as disclosed in the background art above, "adding a precipitant to react with mercury to generate insoluble mercury sulfide in wastewater, adding a flocculant to precipitate insoluble mercury sulfide, increasing the precipitation effect by adding a complexing inhibitor, and further filtering and separating by ultrafiltration and nanofiltration devices to ensure that the discharge meets the standard, this treatment method can effectively remove inorganic mercury and elemental mercury, but the removal effect of organic mercury is not ideal, and the effluent quality completely depends on the mercury removal efficiency of precipitation, which cannot guarantee that the effluent meets the standard stably", in combination with actual use, this problem is obviously a real problem and is relatively difficult to solve, therefore, to solve this technical problem, a mercury removal system suitable for flue gas washing wastewater is provided on this basis.

[0020] As Figure 1 shown in the drawings;

[0021] In combination with the above, a wastewater inlet 1 is further arranged on the pH adjusting area 2, and the precipitation area 6, the sand filter tank 7, the carbon filter tank 9 and the resin tank 11 are connected through pipelines.

[0022] In an optional embodiment, quartz sand 8 is added in the sand filter tank 7 to intercept suspended solids in the wastewater.

[0023] In an optional embodiment, activated carbon 10 is added in the carbon filter tank 9 to adsorb organic mercury in the wastewater and further intercept suspended solids.

[0024] In an optional embodiment, mercury removal resin 12 is added in the resin tank 11 to adsorb the remaining inorganic mercury in the wastewater.

[0025] In an optional embodiment, a water outlet 13 is arranged at the bottom end of the resin tank 11.

[0026] In an optional embodiment, a coagulant is added in the coagulation area 4 to make the mercury sulfide gather together to form flocs.

[0027] In an optional embodiment, a flocculant is added in the flocculation area 5 to make the flocs continuously grow and settle.

[0028] Working principle of the utility model:

[0029] First, the pH of the flue gas washing wastewater is adjusted to a suitable value (8-10) for mercury removal reaction in the pH adjustment zone, and then a mercury removal agent such as sodium sulfide is added in the mercury removal reaction zone to react with mercury ions in the wastewater to generate mercury sulfide, which is then removed by coagulation, flocculation and precipitation, and the supernatant after precipitation in the precipitation zone is introduced into a sand filter tank through a pipeline, the sand filter tank is filled with quartz sand of different particle sizes, and the suspended solids in the wastewater are intercepted by the quartz sand, the sand filter tank is connected with a carbon filter tank through a pipeline, the carbon filter tank is filled with activated carbon, and the organic mercury in the wastewater is adsorbed by the activated carbon, and the fine suspended solids are further intercepted, the effluent of the carbon filter tank is introduced into a resin tank through a pipeline, the resin tank is filled with mercury removal resin, and the remaining inorganic mercury in the wastewater is removed by the ion exchange of the functional groups in the resin, the number of the resin tanks is determined according to the actual water quality and the quality of the resin, and the effluent is ensured to be stable and meet the discharge standard.

[0030] Finally, it should be noted that: the above is only the preferred embodiment of the utility model, and is not used to limit the utility model, although the utility model is described in detail with reference to the foregoing embodiments, for those skilled in the art, it still can modify the technical scheme recorded in the foregoing embodiments, or make equivalent replacement to part of the technical features. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the utility model should be included in the protection scope of the utility model.

Claims

1. A mercury removal system suitable for flue gas scrubbing wastewater, comprising a pH adjustment zone (2), a mercury removal reaction zone (3), a coagulation zone (4), a flocculation zone (5), a sedimentation zone (6), a sand filter tank (7), a carbon filter tank (9), a resin tank (11), characterized in that: It also includes a wastewater inlet (1) arranged on the PH adjusting area (2), and the sedimentation area (6), the sand filter tank (7), the carbon filter tank (9) and the resin tank (11) are connected by pipelines.

2. A mercury removal system suitable for flue gas scrubbing wastewater according to claim 1, characterized in that: The sand filter tank (7) is internally added with quartz sand (8) for intercepting suspended solids in the wastewater.

3. A mercury removal system suitable for flue gas scrubbing wastewater according to claim 2, characterized in that: The carbon filter tank (9) is internally added with activated carbon (10) for adsorbing organic mercury in the wastewater and further intercepting suspended solids.

4. A mercury removal system for flue gas scrubbing wastewater according to claim 1, characterized in that: The resin tank (11) is internally added with mercury removal resin (12) for adsorbing residual inorganic mercury in the wastewater.

5. A mercury removal system suitable for flue gas scrubbing wastewater according to claim 1, characterized in that: The resin tank (11) is provided with a water outlet (13) at the bottom end.

6. A mercury removal system suitable for flue gas scrubbing wastewater according to claim 1, characterized in that: Sodium sulfide is added in the mercury removal reaction area (3) to react with mercury ions in the wastewater to generate mercury sulfide.

7. A mercury removal system suitable for flue gas scrubbing wastewater according to claim 1, characterized in that: A coagulant is added in the coagulation area (4) to make the mercury sulfide gather together to form flocs.

8. A mercury removal system suitable for flue gas scrubbing wastewater according to claim 1, characterized in that: A flocculant is added in the flocculation area (5) to make the flocs continuously grow larger and settle.

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