Desulfurization liquid treatment system

Abstract

The utility model relates to the technical field of tail gas recovery, and discloses a variable desulfurization liquid treatment system, which is characterized in that a sedimentation tank is connected with a filter press through a first pipeline, a sedimentation tank pump is arranged on the first pipeline, a slag discharge port of the filter press is connected with a slag discharge pipe, and a liquid discharge port of the filter press is connected with a filtrate tank through a second pipeline; the filtrate tank is connected with a liquid inlet of the evaporation kettle through a third pipeline; the evaporation kettle is connected into a low-pressure steam system, the bottom of the evaporation kettle is connected with a concentrated liquid tank through a liquid outlet, an outlet of the concentrated liquid tank is connected with a concentrated liquid pipe, and the concentrated liquid pipe is connected with a first pipeline; a top exhaust port of the evaporation kettle is connected with the heat exchanger through a fourth pipeline; a condensate outlet of the heat exchanger is connected with a clear liquid tank through a fifth pipeline; a lower outlet of the clear liquid tank is connected with a liquid discharge pipe, the liquid discharge pipe is connected into a transformation and dehydration system, an upper outlet of the clear liquid tank is connected with an air supply outlet of a Roots blower through a sixth pipeline, and an air exhaust outlet of the Roots blower is empty. The system ensures that components of the desulfurization solution can be normally adjusted, and stable operation of the shift gas desulfurization device is maintained.

Description

Technical Field

[0001] The utility model relates to the technical field of waste liquid treatment, in particular to the field of desulfurization waste liquid treatment, and specifically relates to a governance system for shift desulfurization liquid. Background Technique

[0002] In the shift gas desulfurization section, the main components added to the desulfurization liquid are Na 2 CO 3 , NDC 201 , NDC 202 . The principle is as follows: NDC 2 CO 3 is added to the dilute alkali solution of sodium carbonate (Na 201 ), and NDC 202 etc. form the desulfurization liquid. The desulfurization liquid countercurrently contacts with the shift gas in the packing tower to remove H 2 S. The dilute alkali solution absorbing H 2 S is oxidized by air and then the elemental sulfur is floated out, and the clear liquid is recycled in the lean liquid tank.

[0003] The reactions in the system are as follows:

[0004] Na 2 CO 3 +H 2 S = NaHS+NaHCO 3

[0005] Na 2 CO 3 +CO 2 +H 2 O = 2NaHCO 3

[0006] NaHCO 3 +H 2 S = NaHS+H 2 O+CO 2

[0007] The main side reactions are:

[0008] 2NaHS+2O 2 = Na 2 S 2 O 3 +H 2 O

[0009] 2NaHS+2HCN+O 2 = 2NaCNS+2H 2 O

[0010] NaCNS+5O 2 = Na 2 SO4 +2CO 2 +SO 2 +N 2

[0011] In the reaction, thiosulfate and sulfate are by-products of the desulfurization process. During the operation of the desulfurization system, the increase of by-products such as thiosulfate and sulfate, among which, Na 2 SO 4 The index is <150 g / l, while in the worst field conditions, the content of Na 2 SO 4 reaches 182.03 g / l, resulting in an increase in the viscosity of the desulfurization solution, a decrease in the flotation efficiency, affecting the absorption of H 2 S gas, and affecting the regeneration of the desulfurization solution. The increase in the sulfate content will also cause equipment corrosion, the output of sulfur foam is significantly lower than the theoretical sulfur output, the consumption of chemical auxiliary materials increases, and environmental pollution is caused. To ensure the normal operation of the desulfurization system, the desulfurization solution needs to be replaced. During the current operation, the waste liquid generated by the sulfur melting kettle, the drainage from each tower and tank drain, and the waste liquid generated during maintenance are all discharged into the sedimentation tank. It is difficult to treat this part of the desulfurization waste liquid. Therefore, when the content of by-products reaches a certain level, treatment is required to reduce the content of by-products in the solution and ensure the safe and stable operation of the desulfurization device. To solve the above problems, a governance system for the variable desulfurization solution is provided. Summary of the Invention

[0012] The utility model aims to solve the problems that in the current desulfurization process of the shift gas desulfurization section, the increase of by-products leads to an increase in the viscosity of the desulfurization solution, a decrease in the flotation efficiency, affecting the absorption of H 2 S gas, and affecting the regeneration of the desulfurization solution, and treatment is required to reduce the content of by-products in the solution and ensure the safe and stable operation of the desulfurization device, and provides a governance system for the variable desulfurization solution.

[0013] The utility model is realized by adopting the following technical solutions:

[0014] A governance system for the variable desulfurization solution includes a sedimentation tank, the sedimentation tank is connected to a filter press through a first pipeline, a sedimentation tank pump is provided on the first pipeline, the slag discharge port of the filter press is connected to a slag discharge pipe, the liquid discharge port of the filter press is connected to a filtrate tank through a second pipeline, and the filtrate tank is connected to the liquid inlet of an evaporation kettle through a third pipeline; the evaporation kettle is connected to a low-pressure steam system, the bottom of the evaporation kettle is connected to a concentrated liquid tank through a liquid outlet, the outlet of the concentrated liquid tank is connected with a concentrated liquid pipe, and the concentrated liquid pipe is connected to the first pipeline; the exhaust port at the top of the evaporation kettle is connected to a heat exchanger through a fourth pipeline; the condensate outlet of the heat exchanger is connected to a clear liquid tank through a fifth pipeline; the lower outlet of the clear liquid tank is connected to a liquid discharge pipe, and the liquid discharge pipe is connected to the variable desulfurization system, the upper outlet of the clear liquid tank is connected to the air supply port of a Roots blower through a sixth pipeline, and the exhaust port of the Roots blower is connected to the air.

[0015] During implementation, it includes a sedimentation tank. The sedimentation tank is connected to a filter press through a first pipeline. A sedimentation tank pump is provided on the first pipeline. A first valve is provided at the front end of the sedimentation tank pump on the first pipeline. The slag discharge port of the filter press is connected to a slag discharge pipe, and a slag discharge valve is installed on the slag discharge pipe. The liquid discharge port of the filter press is connected to a filtrate tank through a second pipeline. The filtrate tank is connected to the liquid inlet of an evaporation kettle through a third pipeline, and a desulfurization liquid pump is installed on the third pipeline.

[0016] The evaporation kettle is connected to a low-pressure steam system. That is, the low-pressure steam system includes a low-pressure steam pipe and a steam condensate pipe. The low-pressure steam pipe is connected to the steam inlet of the evaporation kettle, and the steam condensate pipe is connected to the condensate outlet of the evaporation kettle. The bottom of the evaporation kettle is connected to a concentrated liquid tank through a liquid outlet. The outlet of the concentrated liquid tank is connected to a concentrated liquid pipe, and a third valve is provided on the concentrated liquid pipe. The concentrated liquid pipe is connected to the first pipeline. Specifically, the outlet of the concentrated liquid pipe is connected between the first valve and the sedimentation tank pump on the first pipeline. Through the cooperation of the first valve and the third valve, the proportion of the treated desulfurization waste liquid entering the system can be selected. The exhaust port at the top of the evaporation kettle is connected to a heat exchanger through a fourth pipeline. The top and bottom of the heat exchanger are respectively connected to a return water pipe and a water supply pipe.

[0017] The condensate outlet of the heat exchanger is connected to a clear liquid tank through a fifth pipeline.

[0018] The lower outlet of the clear liquid tank is connected to a liquid discharge pipe, and the liquid discharge pipe is connected to the variable desulfurization system. The upper outlet of the clear liquid tank is connected to the air supply port of a Roots blower through a sixth pipeline. The Roots blower maintains the vacuum degree in the evaporation kettle, and the exhaust port of the Roots blower is open to the air.

[0019] During use, the desulfurization waste liquid is pumped from the sedimentation tank into the filter press through the first pipeline under the action of the sedimentation tank pump. In the filter press, impurities such as sulfur sludge in the desulfurization waste liquid are filtered. The filtrate of the desulfurization waste liquid enters the filtrate tank from the liquid discharge port through the second pipeline. The filter residue after filtering for a period of time is treated as waste residue in an environmental protection manner through the slag discharge pipe from the slag discharge port. The filtrate of the desulfurization waste liquid is sent into the evaporation kettle under the action of the desulfurization liquid pump. The evaporation kettle maintains the evaporation temperature through the existing low-pressure steam system. Specifically, the low-pressure steam in the low-pressure steam system enters the evaporation kettle from the low-pressure steam pipe and returns to the low-pressure steam system through the steam condensate pipe after condensation for re-circulation. The filtrate of the desulfurization waste liquid in the evaporation kettle is heated and evaporated. After evaporation at the upper part, it first enters the heat exchanger through the fourth pipeline from the exhaust port for condensation. The heat exchanger maintains the condensation temperature of the heat exchanger through the water supply pipe and the return water pipe. The condensate is discharged from the heat exchanger and collected in the clear liquid tank through the fifth pipeline. After reaching the preset liquid level in the clear liquid tank, it is discharged from the liquid discharge pipe and sent back to the variable desulfurization system through the liquid preparation tank for system liquid preparation. The upper outlet of the clear liquid tank is connected to the Roots blower, and the evaporation kettle is evacuated by the Roots blower to ensure continuous evaporation of the evaporation kettle. In addition, the unevaporated liquid in the evaporation kettle is concentrated in the concentrated liquid tank through the lower liquid outlet. The density in the concentrated liquid tank is about 1.3×10 3kg / m 3 ~1.6×10 3 kg / m 3 The concentrated liquid tank is connected to the first pipeline through the concentrated liquid pipe, and the concentrated liquid re-enters the system. The first valve is closed, and the third valve is opened to pump the concentrated liquid into the filter press. After the filter press filters out the salt, the filtrate enters this system, and the waste salt is environmentally treated.

[0020] Compared with the prior art, the utility model has the following beneficial effects:

[0021] A governance system for the variable desulfurization liquid provided by the utility model extracts salt from the desulfurization liquid of the system through the evaporation and concentration method. The evaporation kettle is evacuated to a slightly negative pressure by a Roots blower to reduce the saturated vapor pressure of the desulfurization liquid, and the solution temperature is heated to about 90 °C to evaporate the desulfurization solution into a saturated solution. The evaporated solution on the upper layer is separated and returned to the liquid preparation tank for system liquid preparation, and the concentrated desulfurization liquid on the lower layer is processed according to the hazardous waste process; it effectively solves the difficulty of replacing the desulfurization solution of the shift gas at present, ensures that the components of the desulfurization solution can be adjusted normally, and maintains the long-term stable operation of the shift gas desulfurization device. This system is recycled, relying on the existing operators and managers of the variable desulfurization device, without the need for new personnel and without causing additional waste. Brief Description of the Drawings

[0022] Figure 1 It shows the structural schematic diagram of the utility model.

[0023] In the figure: 1 - sedimentation tank, 2 - filter press, 3 - sedimentation tank pump, 4 - filtrate tank, 5 - evaporation kettle, 501 - liquid inlet, 502 - liquid outlet, 503 - exhaust port, 6 - concentrated liquid tank, 7 - heat exchanger, 8 - clear liquid tank, 9 - Roots blower, 901 - air supply port, 902 - air discharge port, 10 - slag discharge valve, 11 - first valve, 13 - third valve;

[0024] L1 - first pipeline, L2 - second pipeline, L3 - third pipeline, L4 - fourth pipeline, L5 - fifth pipeline, L6 - sixth pipeline, L7 - slag discharge pipe, L8 - low-pressure steam pipe, L9 - steam condensate pipe, L10 - concentrated liquid pipe, L11 - return water pipe, L12 - water supply pipe, L13 - liquid discharge pipe. Detailed Embodiments

[0025] The specific embodiments of the utility model will be described below with reference to the drawings.

[0026] A governance system for the variable desulfurization liquid, such as Figure 1As shown in the figure: It includes a sedimentation tank 1. The sedimentation tank 1 is connected to a filter press 2 through a first pipeline L1. A sedimentation tank pump 3 is provided on the first pipeline L1. A first valve 11 is provided at the front end of the first pipeline L1 before the sedimentation tank pump 3. The slag discharge port of the filter press 2 is connected to a slag discharge pipe L7. A slag discharge valve 10 is installed on the slag discharge pipe L7. The liquid discharge port of the filter press 2 is connected to a filtrate tank 4 through a second pipeline L2. The filtrate tank 4 is connected to the liquid inlet 501 of an evaporation kettle 5 through a third pipeline L3. A desulfurization liquid pump 12 is installed on the third pipeline L3;

[0027] The evaporation kettle 5 is connected to a low-pressure steam system. That is, the low-pressure steam system includes a low-pressure steam pipe L8 and a steam condensate pipe L9. The low-pressure steam pipe L8 is connected to the steam inlet of the evaporation kettle. The steam condensate pipe L9 is connected to the condensate outlet of the evaporation kettle 5. The bottom of the evaporation kettle 5 is connected to a concentrated liquid tank 6 through a liquid outlet 502. The outlet of the concentrated liquid tank 6 is connected to a concentrated liquid pipe L10. A third valve 13 is provided on the concentrated liquid pipe L10. The concentrated liquid pipe L10 is connected to the first pipeline L1. Specifically, the outlet of the concentrated liquid pipe L10 is connected between the first valve 11 and the sedimentation tank pump 3 on the first pipeline L1. Through the cooperation of the first valve 11 and the third valve 13, the proportion of the treated desulfurization waste liquid entering the system can be selected. The top exhaust port 503 of the evaporation kettle 5 is connected to a heat exchanger 7 through a fourth pipeline L4. The top and bottom of the heat exchanger 7 are respectively connected to a return water pipe L11 and a water supply pipe L12;

[0028] The condensate outlet of the heat exchanger 7 is connected to a clear liquid tank 8 through a fifth pipeline L5;

[0029] The lower outlet of the clear liquid tank 8 is connected to a liquid discharge pipe L13. The liquid discharge pipe L13 is connected to a variable desulfurization system. The upper outlet of the clear liquid tank 8 is connected to the air supply port 901 of a Roots blower 9 through a sixth pipeline L6. The Roots blower 9 maintains the vacuum degree in the evaporation kettle 5. The exhaust port 902 of the Roots blower 9 is open to the air.

[0030] In use, the desulfurized waste liquid is pumped from the sedimentation tank 1 into the filter press 2 through the first pipeline L1 by the action of the sedimentation tank pump 3. In the filter press 2, impurities such as sulfur sludge in the desulfurized waste liquid are filtered. The filtrate of the desulfurized waste liquid enters the filtrate tank 4 through the second pipeline L2 from the drain port. The filter residue after filtering for a period of time is treated in an environmentally friendly manner through the slag discharge pipe L7 at the slag discharge port; the filtrate of the desulfurized waste liquid is sent to the evaporation kettle 5 under the action of the desulfurized liquid pump 12. The evaporation kettle 5 maintains the evaporation temperature through an existing low-pressure steam system. Specifically, the low-pressure steam in the low-pressure steam system enters the evaporation kettle 5 from the low-pressure steam pipe L8, heating the solution temperature in the evaporation kettle 5 to about 90°C, evaporating the desulfurized solution in the evaporation kettle 5 into a saturated solution, and returning to the low-pressure steam system for recycling after condensation through the steam condensate pipe L9; the filtrate of the desulfurized waste liquid is heated and evaporated in the evaporation kettle 5. The evaporated solution on the upper layer is separated and returned to the liquid preparation tank for system liquid preparation. After evaporation on the upper part, it first enters the heat exchanger 7 through the fourth pipeline L4 from the exhaust port for condensation. The heat exchanger 7 maintains the condensation temperature of the heat exchanger 7 through the water supply pipe L12 and the return water pipe L11; the condensate is discharged from the heat exchanger 7 and collected in the clear liquid tank 8 through the fifth pipeline L5; after reaching the preset liquid level in the clear liquid tank 8, it is discharged from the drain pipe L13 and sent to the liquid preparation tank to return to the variable desulfurization system for system liquid preparation; the upper outlet of the clear liquid tank 8 is connected to the Roots blower 9 to evacuate the evaporation kettle 5 to a slightly negative pressure, and the Roots blower 9 evacuates the evaporation kettle 5 to ensure continuous evaporation of the evaporation kettle 5 and reduce the saturated vapor pressure of the desulfurized liquid.

[0031] In addition, the concentrated desulfurized liquid at the lower layer of the evaporation kettle 5 is treated according to the hazardous waste process. The unevaporated liquid in the evaporation kettle 5 is concentrated in the concentrated liquid tank 6 through the lower liquid outlet. The density in the concentrated liquid tank is about 1.3×10 3 kg / m 3 ~1.6×10 3 kg / m 3 . The concentrated liquid tank 6 is connected to the first pipeline L1 through the concentrated liquid pipe L10, and the concentrated liquid re-enters the system. The first valve is closed, the third valve 13 is opened, and the concentrated liquid is pumped into the filter press 2. After the filter press 2 filters the salt, the filtrate enters this system, and the waste salt is treated in an environmentally friendly manner.

[0032] This system is connected to the variable desulfurization system to test the treatment capacity of this system. Among them, the evaporation kettle 5, the heat exchanger 7, the Roots blower 9, the clear liquid tank 8, and the concentrated liquid tank 6 are installed on the east side frame of the sulfur melting kettle. The sedimentation tank pump 3, the desulfurized liquid pump 12, the filter press 2, and the filtrate tank 4 are installed at the original rich liquid tank position, and the old secondary liquid tank is removed.

[0033] Through on-site practical tests, the treatment capacity of this system is 5m 3 / d, the feed concentration is density > 1.1×10 3 kg / m 3 , and the concentration of the discharged concentrated liquid is 1.3×103 kg / m 3 ~1.6×10 3 kg / m 3 , meeting the processing requirements, this system can operate independently without affecting the production device of the transformation desulfurization.

[0034] The scope of protection claimed by this utility model is not limited to the above specific embodiments. Moreover, for those skilled in the art, this utility model can have various deformations and modifications. Any modification, improvement, and equivalent replacement made within the concept and principle of this utility model should be included within the scope of protection of this utility model.

Claims

1. A system for treating desulfurization liquid by a desulfurization process, comprising a sedimentation tank (1), characterized in that: The sedimentation tank (1) is connected to the filter press (2) via a first pipeline (L1), a sedimentation tank pump (3) is provided on the first pipeline (L1), a slag discharge port of the filter press (2) is connected to a slag discharge pipe (L7), a liquid discharge port of the filter press (2) is connected to a filtrate tank (4) via a second pipeline (L2), and the filtrate tank (4) is connected to a liquid inlet (501) of an evaporating kettle (5) via a third pipeline (L3); The evaporator (5) is connected to a low-pressure steam system; the bottom of the evaporator (5) is connected to a concentrated liquid tank (6) via a liquid outlet (502); the outlet of the concentrated liquid tank (6) is connected to a concentrated liquid pipe (L10); the concentrated liquid pipe (L10) is connected to a first pipeline (L1); the top exhaust port (503) of the evaporator (5) is connected to a heat exchanger (7) via a fourth pipeline (L4); The condensate outlet of the heat exchanger (7) is connected to a clear liquid tank (8) via a fifth pipeline (L5); The lower outlet of the clear liquid tank (8) is connected to a drain pipe (L13), and the drain pipe (L13) is connected to a variable temperature system. The upper outlet of the clear liquid tank (8) is connected to an air supply port (901) of a Roots blower (9) via a sixth pipeline (L6), and an air outlet (902) of the Roots blower (9) is connected to air.

2. A system for treating desulfurization liquid according to claim 1, characterized in that: The first pipeline (L1) is provided with a first valve (11) at the front end of the sedimentation tank pump (3); the first pipeline (L1) is connected to the outlet of the concentrate pipe (L10) between the first valve (11) and the sedimentation tank pump (3); and the concentrate pipe (L10) is provided with a third valve (13).

3. A system for treating desulfurization liquid according to claim 1, characterized in that: The low-pressure steam system comprises a low-pressure steam pipe (L8) and a steam condensate pipe (L9), wherein the low-pressure steam pipe (L8) is connected to the steam inlet of the evaporator, and the steam condensate pipe (L9) is connected to the condensate outlet of the evaporator (5).

4. A system for treating desulfurization liquid according to claim 1, characterized in that: The top and bottom of the heat exchanger (7) are respectively connected to a water return pipe (L11) and a water supply pipe (L12).

5. A system for treating desulfurization liquid according to claim 1, characterized in that: A desulfurization liquid pump (12) is installed on the third pipeline (L3).

6. A system for treating desulfurization liquid according to claim 1, characterized in that: The slag discharge pipe (L7) is provided with a slag discharge valve (10).

7. A system for treating desulfurization liquid according to claim 1, characterized in that: The Roots blower (9) maintains the vacuum degree in the evaporator (5).

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