Mercury-containing waste thermal desorption treatment tail gas purification system

Abstract

The utility model discloses a mercury-containing waste thermal desorption treatment tail gas purification system which comprises an oxidation tower, a vulcanization reaction tower, a demisting tower, an activated carbon adsorption tower, an induced draft fan and a chimney which are connected in sequence, the system further comprises a cyclone dust collector, a filter dust collector, an indirect heat exchanger and a deep condenser, the input end of the cyclone dust collector is connected with the output end of the thermal desorption chamber, the cyclone dust collector, the filter dust collector, the indirect heat exchanger and the deep condenser are sequentially connected, and the output end of the deep condenser is connected with the input end of the oxidation tower. According to the tail gas purification system for thermal desorption treatment of the mercury-containing waste provided by the utility model, elemental mercury in the high-temperature steam can be removed after the mercury-containing high-temperature steam is subjected to two-time dust removal and two-time condensation, and the mercury-containing waste gas is thoroughly treated in cooperation with subsequent treatment, so that the mercury-containing waste gas stably reaches the standard, and secondary pollution to the environment is avoided.

Description

TECHNICAL FIELD

[0001] The utility model relates to flue gas purification technical field, concretely relates to a kind of mercury-containing waste heat desorption treatment tail gas purification system. BACKGROUND

[0002] Soil is the basic structural unit of biosphere, is the important component of environment, is precious renewable resource.Soil pollution problem is increasingly serious in our country, epidemic statistics and scientific research have fully proved that the pollution degree of human health and surrounding soil environment etc.

[0003] According to the utility model patent application with the announcement number CN207042219U, the announcement day is February 27, 2018, a kind of mercury pollution soil heat desorption tail gas purification system is disclosed, including spray washing tower, oxidation tower, sulfurization reaction tower, demisting tower, activated carbon adsorption tower, induced draft fan and chimney, spray washing tower import and pyrolysis chamber outlet connection are communicated, and the outlet of spray washing tower is connected with the import of oxidation tower, and the outlet of oxidation tower is connected with the import of sulfurization reaction tower, and the outlet of sulfurization reaction tower is connected with the import of demisting tower, and the outlet of demisting tower is connected with the import of activated carbon adsorption tower, and the outlet of activated carbon adsorption tower is connected with the import of induced draft fan, and the outlet of induced draft fan is connected with chimney, and the outlet of induced draft fan is equipped with mercury vapor concentration on-line monitoring equipment.The number of activated carbon adsorption tower is multiple, and is connected in parallel, when on-line monitoring equipment detects that mercury vapor concentration of induced draft fan outlet is close to emission limit value, on-line switches activated carbon adsorption tower, to ensure that emission gas meets the standard.The main technical effect is that mercury-containing waste gas can be completely treated, so that it is stable and meets the standard, and secondary pollution to the environment is avoided.

[0004] At present, there are many remediation measures for soil mercury pollution, such as using traditional waste gas purification system to dispose waste gas in soil remediation process, but such purification system is easy to cause pollution transfer in actual application process, i.e. pollution is transferred from soil to gas, which will cause secondary pollution to the environment after emission, therefore, a kind of mercury-containing waste heat desorption treatment tail gas purification system is proposed, which aims to solve the problem that pollution will be transferred from soil to gas in the purification process of traditional waste gas purification system, which will cause secondary pollution to the environment after emission. UTILITY MODEL CONTENT

[0005] The utility model aims to provide a kind of mercury-containing waste heat desorption treatment tail gas purification system, to solve the problem that pollution will be transferred from soil to gas in the purification process of traditional waste gas purification system, which will cause secondary pollution to the environment after emission.

[0006] In order to achieve the above object, the utility model provides the following technical scheme:

[0007] A kind of mercury-containing waste thermal desorption treatment tail gas purification system, including oxidation tower, sulfurization reaction tower, mist eliminator, activated carbon adsorption tower, induced draft fan and chimney, the oxidation tower, sulfurization reaction tower, mist eliminator, activated carbon adsorption tower, induced draft fan and chimney are sequentially connected, it is characterized by further including cyclone dust collector, filter dust collector, indirect heat exchanger and depth condenser, the input end of the cyclone dust collector is connected with the output end of thermal desorption chamber, the cyclone dust collector, filter dust collector, indirect heat exchanger and depth condenser are sequentially connected, and the output end of depth condenser is connected with the input end of oxidation tower.

[0008] As preferred, it further includes cooling tower, and the cooling tower is connected with indirect heat exchanger.

[0009] As preferred, it further includes water chiller, and the water chiller is connected with depth condenser.

[0010] As preferred, the number of activated carbon adsorption tower is several, and the several activated carbon adsorption towers are connected in parallel.

[0011] As preferred, online monitoring equipment is connected between induced draft fan and chimney, and the cyclone dust collector, filter dust collector, indirect heat exchanger, depth condenser, oxidation tower, sulfurization reaction tower, mist eliminator, activated carbon adsorption tower, induced draft fan and online monitoring equipment are integrated in one skid.

[0012] In the above technical scheme, the utility model provides a kind of mercury-containing waste thermal desorption treatment tail gas purification system, with the following beneficial effects:

[0013] The utility model, high-temperature steam generated by thermal desorption chamber is first introduced into cyclone dust collector to carry out first dust removal, and after removing 60%-70% of dust in flue gas, first purification tail gas is obtained;Then, first purification tail gas enters filter dust collector to carry out second dust removal, and removal rate can reach 99%, and the efficient removal of dust can reduce the adverse effects on subsequent equipment and pipeline;After dust removal, tail gas is then introduced into indirect heat exchanger to cool down, and at the same time, sensible heat of steam is recovered and most of elemental mercury is removed;Then, steam is reduced to 20-30 DEG C by deep condensation, to further remove residual elemental mercury in tail gas, and after two times of dust removal and two times of condensation, elemental mercury in high-temperature steam can be removed, and combined with subsequent treatment, complete treatment of mercury-containing waste gas is realized, so that it is stable and up to standard, thereby avoiding secondary pollution of environment. BRIEF DESCRIPTION OF DRAWINGS

[0014] In order to make the technical scheme of the present application or the prior art clearer, the drawings needed in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments described in the present application, and other drawings can also be obtained by those skilled in the art according to these drawings.

[0015] Figure 1 The system composition structure diagram provided by the embodiment of the present application.

[0016] Mark explanation:

[0017] 1, oxidation tower; 2, sulfuration reaction tower; 3, mist eliminator; 4, activated carbon adsorption tower; 5, induced draft fan; 6, chimney; 7, cyclone dust collector; 8, filter dust collector; 9, indirect heat exchanger; 10, deep condenser; 11, cooling tower; 12, water chiller. DETAILED DESCRIPTION

[0018] In order to make the technical scheme of the present application or the prior art clearer, the drawings needed in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments described in the present application, and other drawings can also be obtained by those skilled in the art according to these drawings.

[0019] Please refer to Figure 1 A kind of mercury-containing waste thermal desorption treatment tail gas purification system, including oxidation tower 1, sulfuration reaction tower 2, mist eliminator 3, activated carbon adsorption tower 4, induced draft fan 5 and chimney 6, oxidation tower 1, sulfuration reaction tower 2, mist eliminator 3, activated carbon adsorption tower 4, induced draft fan 5 and chimney 6 are sequentially connected, still including cyclone dust collector 7, filter dust collector 8, indirect heat exchanger 9 and deep condenser 10, the input end of cyclone dust collector 7 is connected with pyrolysis chamber output end, cyclone dust collector 7, filter dust collector 8, indirect heat exchanger 9, deep condenser 10 and caustic washing tower are sequentially connected, and the output end of caustic washing tower is connected with the input end of oxidation tower 1.

[0020] Pyrolysis chamber is connected with cyclone dust collector 7, high temperature vapor generated in pyrolysis chamber can be introduced into cyclone dust collector 7 by cyclone dust collector 7, and part of dust in high temperature vapor is removed.60%-70% of dust in flue gas can be removed, and first-stage purified tail gas is obtained.

[0021] The output end of cyclone dust collector 7 is connected with the input end of filter dust collector 8, and the first-stage purified tail gas filtered by cyclone dust collector 7 can be filtered by filter dust collector 8 for secondary filtration, to obtain dust-removed tail gas.99% of dust in dust-removed tail gas filtered by filter dust collector 8 can be removed, to realize efficient removal of dust.Efficient removal of dust can reduce adverse effects on subsequent equipment and pipelines.

[0022] The output end of the filter dust cleaner 8 is connected with the input end of the indirect heat exchanger 9, the tail gas after dust removal is cooled by the indirect heat exchanger, the sensible heat of the steam is recovered, and the elemental mercury is removed.

[0023] The output end of the indirect heat exchanger 9 is connected with the input end of the deep condenser 10, the steam is converted into non-condensable gas by deep condensation, and the temperature of the steam is reduced to 20-30 DEG C, so that the zero-valent mercury in the steam is removed.

[0024] The output end of the deep condenser 10 is connected with the oxidation tower 1, the non-condensable gas is oxidized into divalent mercury in the oxidation tower 1 under the oxidation of the oxidant.

[0025] The output end of the oxidation tower 1 is connected with the sulfuration reaction tower 2, the non-condensable gas reacts with the sulfuration agent to form sulfuration mercury precipitation in the sulfuration reaction tower 2, and the non-condensable gas is removed.

[0026] The output end of the sulfuration reaction tower 2 is connected with the demisting tower 3, the non-condensable gas flows out of the sulfuration reaction tower 2 and enters the demisting tower 3, and the liquid droplets entrained in the non-condensable gas are removed by the demisting tower 3.

[0027] The output end of the demisting tower 3 is connected with the activated carbon adsorption tower 4, the non-condensable gas enters the activated carbon adsorption tower 4, and the trace residual mercury and its compounds in the non-condensable gas are removed by adsorption.

[0028] The output end of the activated carbon adsorption tower 4 is connected with the induced draft fan 5, the flue gas is sucked by the induced draft fan 5 and is discharged into the atmosphere through the chimney 6. The mercury vapor concentration on-line monitoring equipment is arranged at the outlet of the induced draft fan 5, and the concentration of mercury vapor in the discharged gas can be monitored in real time.

[0029] The on-line monitoring equipment arranged at the outlet of the induced draft fan 5 can monitor the concentration of mercury vapor in the discharged gas in real time; the on-line monitoring equipment and the plurality of parallelly connected activated carbon adsorption towers 4 are combined to automatically switch the working number of the activated carbon adsorption towers 4 in time when the flue gas emission approaches the limit value.

[0030] Specifically, the number of the activated carbon adsorption towers 4 is multiple, the plurality of activated carbon adsorption towers 4 are parallelly connected, the working number of the activated carbon adsorption towers 4 is switched on-line when the mercury vapor concentration on-line monitoring equipment detects that the mercury vapor concentration at the outlet of the induced draft fan 5 approaches the emission limit value, and the discharged gas can meet the standard. The combination of the mercury vapor concentration on-line monitoring equipment and the plurality of parallelly connected activated carbon adsorption towers 4 can automatically switch the working number of the activated carbon adsorption towers 4 in time when the flue gas emission approaches the limit value, and the cost can be effectively saved while ensuring that the discharged flue gas meets the standard.

[0031] The cyclone dust collector 7, the filter dust collector 8, the indirect heat exchanger 9, the deep condenser 10, the oxidation tower 1, the sulfuration reaction tower 2, the demisting tower 3, the activated carbon adsorption tower 4, the induced draft fan 5 and the online monitoring equipment are integrated in one skid, facilitating transportation and realizing rapid assembly, so that the shortcomings of the traditional waste gas purification system, such as large size, complex installation and debugging and high cost, are solved.

[0032] Working principle:

[0033] The high-temperature vapor generated by the thermal desorption chamber is first introduced into the cyclone dust collector 7 to perform first dust removal, and after 60%-70% of the dust in the flue gas is removed, first-stage purified tail gas is obtained;

[0034] Then, the first-stage purified tail gas enters the filter dust collector 8 to perform second dust removal, and the removal rate can reach 99%, and the efficient removal of dust can reduce the adverse effects on subsequent equipment and pipelines;

[0035] The tail gas after dust removal is then introduced into the indirect heat exchanger 9 to perform cooling, and most of the elemental mercury is removed while the sensible heat of the vapor is recovered;

[0036] Then, the vapor enters the deep condenser 10, and is reduced to 20-30 DEG C through deep condensation, further removing the elemental mercury in the tail gas, and obtaining non-condensable gas;

[0037] Then, the non-condensable gas enters the oxidation tower 1, and the mercury in the non-condensable gas is oxidized to divalent mercury under the oxidation of the oxidizing agent, and as an embodiment provided by the utility model, the oxidizing agent is preferably potassium permanganate or sodium hypochlorite, low-temperature plasma or other oxidizing agents, which oxidize the elemental mercury to valence mercury, facilitating the adsorption reaction in the sulfuration tower;

[0038] Then, the non-condensable gas enters the sulfuration reaction tower, reacts with the sulfuration agent to form sulfuration mercury precipitate, and is adsorbed and removed from the non-condensable gas;

[0039] Then, the non-condensable gas enters the demisting tower to remove the liquid droplets entrained in the non-condensable gas;

[0040] Finally, the non-condensable gas enters the activated carbon adsorption tower to adsorb and remove the extremely small amount of residual mercury and its compounds;

[0041] Under the suction of the induced draft fan, the qualified flue gas meeting the standard is discharged into the atmosphere through the chimney.

[0042] In the embodiments provided by the utility model, the application can not only be applied to soil remediation, but also be applied to mercury-containing waste tail gas disposal processes other than soil remediation.

[0043] Those skilled in the art can understand that other similar connection modes can also realize the utility model. For example, welding, bonding or screwing and the like.

[0044] The above has only described certain exemplary embodiments of the present application by way of illustration, and it is needless to say that the described embodiments can be modified in various ways without departing from the spirit and scope of the present application for those skilled in the art. Therefore, the above drawings and descriptions are illustrative in nature, and should not be understood as limiting the scope of protection of the claims of the present application.

Claims

1. A tail gas purification system for thermal desorption treatment of mercury-containing waste, comprising an oxidation tower (1), a sulfidation reaction tower (2), a demister (3), an activated carbon adsorption tower (4), an induced draft fan (5), and a chimney (6), wherein the oxidation tower (1), the sulfidation reaction tower (2), the demister (3), the activated carbon adsorption tower (4), the induced draft fan (5), and the chimney (6) are connected in sequence, characterized in that, It also includes a cyclone dust collector (7), a filter dust collector (8), an indirect heat exchanger (9), and a deep condenser (10). The input end of the cyclone dust collector (7) is connected to the output end of the thermal desorption chamber. The cyclone dust collector (7), the filter dust collector (8), the indirect heat exchanger (9), and the deep condenser (10) are connected in sequence. The output end of the deep condenser (10) is connected to the input end of the oxidation tower (1).

2. The tail gas purification system for thermal desorption treatment of mercury-containing waste according to claim 1, characterized in that, It also includes a cooling tower (11), which is connected to an indirect heat exchanger (9).

3. The tail gas purification system for thermal desorption treatment of mercury-containing waste according to claim 1, characterized in that, It also includes a chiller (12) connected to a deep condenser (10).

4. The tail gas purification system for thermal desorption treatment of mercury-containing waste according to claim 1, characterized in that, The number of activated carbon adsorption towers (4) is several, and the several activated carbon adsorption towers (4) are connected in parallel.

5. The tail gas purification system for thermal desorption treatment of mercury-containing waste according to claim 1, characterized in that, An online monitoring device is connected between the induced draft fan (5) and the chimney (6). The cyclone dust collector (7), filter dust collector (8), indirect heat exchanger (9), deep condenser (10), oxidation tower (1), sulfidation reaction tower (2), demister tower (3), activated carbon adsorption tower (4), induced draft fan (5) and online monitoring device are integrated into one skid.

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