Alkaline gas recycling system after semi-coke organic wastewater treatment

Abstract

The utility model belongs to the technical field of waste gas treatment, and particularly relates to an alkaline gas recycling system after semi-coke organic wastewater treatment, which comprises an alkaline gas conveying pipe, a super ammonia absorber, a circulating water inlet pipe, a circulating water outlet pipe, an ammonia water tank and a boiler denitration section, the alkaline gas conveying pipe, the super ammonia absorber, the ammonia water tank and the boiler denitration section are sequentially communicated, and the circulating water inlet pipe is communicated with the circulating water outlet pipe through the super ammonia absorber. According to the device, ammonia gas is dissolved and diluted and then conveyed to a denitration section of a power plant boiler to be reused as a denitration agent, so that the problems of high treatment cost of alkaline gas and secondary pollution to the environment after semi-coke organic wastewater treatment are solved.

Description

TECHNICAL FIELD

[0001] The utility model belongs to waste gas treatment technical field especially relates to a kind of alkaline gas recycling system after organic waste water of coke oven gas treatment. BACKGROUND

[0002] Organic waste water of coke oven gas is mainly the waste water generated in the process of coal low-temperature dry distillation. This dry distillation process is usually carried out at a temperature of 450℃ to 650℃. Because the temperature is relatively low, many organic matters cannot be cracked at high temperature, but remain in the waste water, resulting in a very high concentration of coal tar and low-molecular organic matters in the coke oven gas waste water. The current common treatment process includes oil removal pretreatment, ammonia evaporation and depoisoning, and biochemical treatment.

[0003] The alkaline gas generated after the existing organic waste water of coke oven gas treatment is more than 90% ammonia gas in mass concentration. The existing treatment method for this part of alkaline gas is centralized collection, purification treatment and discharge, which cannot well recycle this part of alkaline gas, resulting in resource waste. The existing alkaline gas recycling also refers to the Chinese invention patent with the publication number CN110790336A, which discloses a device for extracting ammonia gas from coke oven gas waste water to prepare nitrogen fertilizer. Water vapor is introduced into the waste water tank containing coke oven gas waste water, and ammonia gas is overflowed from the coke oven gas waste water into the steam under the action of concentration difference, to realize the extraction of ammonia gas. After the ammonia gas is cooled into liquid ammonia water, it is combined with CO2 to synthesize nitrogen fertilizer. Although the recycling of alkaline gas after the treatment of organic waste water of coke oven gas can be realized, an additional reaction device system needs to be built, the investment in the treatment process is large, the cost is high, and there is a problem of secondary pollution in the process of preparing nitrogen fertilizer from ammonia water and carbon dioxide, which cannot completely realize zero emission in the production process. UTILITY MODEL CONTENT

[0004] In view of the technical problems of high cost and secondary pollution in the treatment of alkaline gas after the treatment of organic waste water of coke oven gas, the utility model provides a kind of alkaline gas recycling system after organic waste water of coke oven gas treatment.

[0005] The utility model discloses a kind of ammonia gas, and then it is transported to power plant boiler denitration section as denitration agent recycling, solve the problem of high cost and secondary pollution to environment in the treatment of alkaline gas after the treatment of organic waste water of coke oven gas.

[0006] To achieve the above purpose, the technical scheme adopted by the utility model is as follows:

[0007] A kind of alkaline gas recycling system after organic waste water of coke oven gas treatment, including alkaline gas conveying pipe, super ammonia absorber, circulating water inlet pipe, circulating water outlet pipe, ammonia water tank and boiler denitration section;The alkaline gas conveying pipe, super ammonia absorber, ammonia water tank and boiler denitration section are sequentially communicated, and the circulating water inlet pipe is communicated with the circulating water outlet pipe through the super ammonia absorber.

[0008] Furthermore, a flow meter and an alkaline gas filter are sequentially installed on the alkaline gas conveying pipe along the conveying direction.

[0009] Further specifying, a circulating water inlet control valve and a circulating water filter are sequentially installed on the circulating water inlet pipe along the water flow direction.

[0010] Furthermore, a circulating water outlet control valve is installed on the circulating water outlet pipe.

[0011] Furthermore, the alkaline gas reuse system after the treatment of semi-coke organic wastewater also includes an ammonia inlet valve installed between the ammonia tank and the boiler denitrification section.

[0012] Further specified, the outer wall of the ammonia tank is connected from top to bottom to an ammonia tank inlet pipe, an ammonia tank overflow pipe, an ammonia tank outlet pipe, and an ammonia tank return pipe; the ammonia tank inlet pipe is connected to the bottom of the super ammonia absorber; the ammonia tank outlet pipe is connected to the boiler denitrification section via an ammonia inlet valve; the ammonia tank overflow pipe is connected to the boiler denitrification section via an ammonia inlet valve; one end of the ammonia tank return pipe is connected to the ammonia tank via the ammonia tank outlet pipe, and the other end of the ammonia tank return pipe is connected to the upper side wall of the super ammonia absorber.

[0013] Further specified, an ammonia water filter, an ammonia water transfer pump, and an ammonia water check valve are sequentially installed on the outlet pipe of the ammonia water tank along the flow direction of the material.

[0014] Further specifying, the alkaline gas reuse system after the treatment of semi-coke organic wastewater also includes a tail gas purifier; the top of the ammonia tank is connected to an ammonia tank exhaust pipe, and the ammonia tank is connected to the tail gas purifier through the ammonia tank exhaust pipe.

[0015] Furthermore, the alkaline gas reuse system after the treatment of semi-coke organic wastewater also includes a water storage tank located between the ammonia tank exhaust pipe and the tail gas purifier; the water storage tank is also connected to the super ammonia absorber and the ammonia tank respectively.

[0016] Furthermore, the alkaline gas reuse system after the treatment of semi-coke organic wastewater also includes a return material control valve; the water storage tank is connected to the super ammonia absorber and the ammonia tank respectively via the return material control valve.

[0017] Compared with existing technologies, the beneficial effects of this utility model are:

[0018] 1. This utility model solves the problems of high treatment costs and secondary environmental pollution caused by alkaline gas after treatment of semi-coke organic wastewater by setting up an alkaline gas conveying pipe, a super ammonia absorber, a circulating water inlet pipe, a circulating water outlet pipe, an ammonia tank, and a boiler denitrification section. The ammonia gas is then dissolved and diluted and transported to the boiler denitrification section of the power plant for reuse as a denitrification agent. This not only solves the problems of high treatment costs of alkaline gas after semi-coke organic wastewater treatment and the resulting secondary environmental pollution, but also saves raw material costs.

[0019] 2. This utility model facilitates the control of the flow rate of alkaline gas and dissolved water by installing valves on the alkaline gas conveying pipe, the circulating water inlet pipe and the circulating water outlet pipe, thereby obtaining ammonia water indicators that meet the requirements of the denitrification agent.

[0020] 3. This utility model, by setting an overflow pipe for the ammonia tank, discharges the ammonia water from the tank when the liquid level is high, and returns the ammonia water to the super ammonia absorber when the required denitrification dosage for the subsequent boiler denitrification section is low, thus ensuring the stable and continuous operation of the system.

[0021] 4. This utility model purifies undissolved gases by setting up an exhaust gas purifier, thus avoiding environmental pollution.

[0022] 5. This utility model improves the ammonia recovery rate by setting a water storage tank between the ammonia tank exhaust pipe and the tail gas purifier to perform secondary dissolution of undissolved gas. Attached Figure Description

[0023] Figure 1 This is the alkaline gas reuse system after treating semi-coke organic wastewater provided in Example 1;

[0024] Figure 2 This is a schematic diagram of the connection of the ammonia tank outlet pipe;

[0025] Figure 3 This is the alkaline gas reuse system after treating semi-coke organic wastewater provided in Example 2;

[0026] Figure 4 Schematic diagram of the return pipe connection for the water storage tank;

[0027] 1-Alkaline gas conveying pipe; 101-Flow meter; 102-Alkaline gas filter; 2-Super ammonia absorber; 3-Circulating water inlet pipe; 301-Circulating water inlet control valve; 302-Circulating water filter; 4-Circulating water outlet pipe; 401-Circulating water outlet control valve; 5-Ammonia tank; 51-Ammonia tank inlet pipe; 52-Ammonia tank overflow pipe; 53-Ammonia tank outlet pipe; 531-Ammonia filter; 532-Ammonia transfer pump; 533-Ammonia check valve Valve; 54-Ammonia tank return pipe; 541-Ammonia return control valve; 542-Ammonia return check valve; 55-Ammonia tank exhaust pipe; 6-Ammonia inlet valve; 7-Boiler denitrification section; 8-Water storage tank; 81-Water storage tank inlet pipe; 82-Water storage tank return pipe; 821-Return filter; 822-Return conveying pump; 823-Return check valve; 83-Water storage tank exhaust pipe; 84-Water storage tank drain pipe; 9-Tail gas purifier; 10-Return control valve. Detailed Implementation

[0028] The preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, so that the advantages and features of the present invention can be more easily understood by those skilled in the art, thereby making a clearer and more definite definition of the scope of protection of the present invention.

[0029] Example 1

[0030] See Figure 1 The alkaline gas reuse system after treating semi-coke organic wastewater provided in this embodiment includes an alkaline gas conveying pipe 1, a super ammonia absorber 2, a circulating water inlet pipe 3, a circulating water outlet pipe 4, an ammonia tank 5, and a boiler denitrification section 7; the alkaline gas conveying pipe 1, the super ammonia absorber 2, the ammonia tank 5, and the boiler denitrification section 7 are connected in sequence, and the circulating water inlet pipe 3 is connected to the circulating water outlet pipe 4 via the super ammonia absorber 2.

[0031] In this embodiment, a flow meter 101 and an alkaline gas filter 102 are sequentially installed on the alkaline gas conveying pipe 1 along the conveying direction.

[0032] In this embodiment, the inlet pressure of the alkaline gas conveying pipe 1 is 0.4–0.5 MPa, the temperature is ≤90℃, and the flow rate is less than 220 kg / h. The alkaline gas contains 90.3% ammonia and 3% total H2S and O2.

[0033] The flow rate of alkaline gas in the alkaline gas conveying pipe 1 is monitored by the flow meter 101, and the alkaline gas filter 102 filters the alkaline gas, mainly filtering sludge or coal slurry impurities.

[0034] In this embodiment, a circulating water inlet control valve 301 and a circulating water filter 302 are sequentially installed on the circulating water inlet pipe 3 along the water flow direction. The circulating water inlet control valve 301 is mainly used to control the opening and closing of dissolved water entering the circulating water inlet pipe 3. The circulating water filter 302 filters the dissolved water, mainly filtering impurities carried in the water to prevent system blockage.

[0035] In this embodiment, a circulating water outlet control valve 401 is installed on the circulating water outlet pipe 4. The circulating water outlet control valve 401 controls the opening and closing of the dissolved water outlet.

[0036] In implementation, the flow rate of alkaline gas is controlled by flow meter 101, and the flow rates of dissolved water are controlled by circulating water inlet control valve 301 and circulating water outlet control valve 401. This allows the dissolved water and alkaline gas to mix in a specific ratio in the super ammonia absorber 2, diluting the ammonia in the alkaline gas to form ammonia water with a volume fraction of 20%, which is then transported to the ammonia water tank 5. In this embodiment, the flow rates controlled by flow meter 101, circulating water inlet control valve 301, and circulating water outlet control valve 401 are determined based on actual operating conditions and are designed and calculated using conventional methods, and are not limited here.

[0037] Preferably, both the alkaline gas filter 102 and the circulating water filter 302 are Y-type filters.

[0038] In this embodiment, the alkaline gas reuse system after treating semi-coke organic wastewater also includes an ammonia inlet valve 6 installed between the ammonia tank 5 and the boiler denitrification section 7. The ammonia inlet valve 6 controls the flow rate of ammonia supplied from the ammonia tank 5 to the boiler denitrification section 7.

[0039] Preferably, to prevent excessive water from entering the boiler denitrification section 7, an ammonia buffer tank is installed between the ammonia inlet valve 6 and the boiler denitrification section 7 to serve as a buffer.

[0040] In this embodiment, the outer wall of the ammonia tank 5 is connected from top to bottom to an ammonia tank inlet pipe 51, an ammonia tank overflow pipe 52, an ammonia tank outlet pipe 53, and an ammonia tank return pipe 54. The ammonia tank inlet pipe 51 is connected to the bottom of the super ammonia absorber 2. The ammonia tank outlet pipe 53 is connected to the boiler denitrification section 7 via the ammonia inlet valve 6. The ammonia tank overflow pipe 52 is connected to the boiler denitrification section 7 via the ammonia inlet valve 6. One end of the ammonia tank return pipe 54 is connected to the ammonia tank 5 via the ammonia tank outlet pipe 53, and the other end of the ammonia tank return pipe 54 is connected to the upper side wall of the super ammonia absorber 2.

[0041] In practice, the ammonia tank feed pipe 51 is used to transport the ammonia water and gaseous impurities discharged from the super ammonia absorber 2 to the ammonia water tank 5. At the same time, a level gauge is installed in the ammonia water tank 5. When the liquid level is higher than the limit, the ammonia water is sent directly from the ammonia water tank overflow pipe 52 to the boiler denitrification section 7 through the ammonia water inlet valve 6 for use.

[0042] During implementation, if the amount of ammonia required by the boiler denitrification section 7 decreases or a malfunction occurs, the ammonia can be returned to the super ammonia absorber 2 through the ammonia tank return pipe 54 to ensure system stability.

[0043] During implementation, for ease of control, an ammonia return control valve 541 and an ammonia return check valve 542 are sequentially installed on the ammonia tank return pipe 54 along the flow direction of the material. When a return is required, the ammonia return control valve 541 and the ammonia return check valve 542 are opened to return excess ammonia to the super ammonia absorber 2. The ammonia return check valve 542 can prevent ammonia from flowing back into the ammonia tank 5.

[0044] In practice, multiple ammonia tank outlet pipes 53 are connected in parallel between the ammonia tank 5 and the ammonia inlet valve 6. Multiple ammonia tank outlet pipes 53 not only increase the ammonia discharge rate but also serve as backups to prevent system shutdown in case of a failure in one of the ammonia tank outlet pipes 53.

[0045] See Figure 1 and Figure 2Preferably, there are two ammonia water tank outlet pipes 53, which are connected in parallel. Each ammonia water tank outlet pipe 53 is equipped with an ammonia water filter 531, an ammonia water transfer pump 532, and an ammonia water check valve 533 along the flow direction of the material.

[0046] Preferably, the ammonia filter 531 is a Y-type filter used to filter impurities in the ammonia water and prevent them from entering the boiler denitrification section 7; the ammonia check valve 533 can prevent ammonia water from flowing back into the ammonia tank 5.

[0047] The ammonia water in the ammonia tank 5, with a volume fraction of 20%, passes through the ammonia water filter 531, the ammonia water transfer pump 532, and the ammonia water check valve 533, and then enters the boiler denitrification section 7 through the ammonia water inlet valve 6. When the boiler denitrification section 7 malfunctions, the ammonia water inlet valve 6 is closed, and the ammonia water return control valve 541 and the ammonia water return check valve 542 are opened, so that the ammonia water returns to the super ammonia absorber 2. When the boiler denitrification section 7 requires less ammonia water, the ammonia water return control valve 541 and the ammonia water return check valve 542 are opened, and a portion of the ammonia water is diverted and returned to the super ammonia absorber 2.

[0048] In this embodiment, the alkaline gas reuse system after treatment of semi-coke organic wastewater also includes a tail gas purifier 9; the top of the ammonia tank 5 is connected to an ammonia tank exhaust pipe 55, and the ammonia tank 5 is connected to the tail gas purifier 9 through the ammonia tank exhaust pipe 55.

[0049] During implementation, for alkaline gases that are not dissolved in water, they enter the exhaust gas purifier 9 through the ammonia tank exhaust pipe 55 at the top of the ammonia tank 5, and are then directly released into the air after purification.

[0050] Example 2

[0051] See Figure 3 Based on Example 1, the alkaline gas reuse system after treatment of semi-coke organic wastewater provided in this example also includes a water storage tank 8 disposed between the ammonia tank exhaust pipe 55 and the tail gas purifier 9; the water storage tank 8 is also connected to the super ammonia absorber 2 and the ammonia tank 5 respectively.

[0052] In this embodiment, the alkaline gas reuse system after the treatment of semi-coke organic wastewater also includes a return control valve 10; the water storage tank 8 is connected to the super ammonia absorber 2 and the ammonia tank 5 via the return control valve 10.

[0053] See Figure 3 and Figure 4The water storage tank 8 is externally connected to a water tank inlet pipe 81, a water tank return pipe 82, a water tank vent pipe 83, and a water tank drain pipe 84. The water tank inlet pipe 81, the water tank vent pipe 83, and the water tank drain pipe 84 are all connected to the top of the water storage tank 8, while the water tank return pipe 82 is connected to the lower side of the water storage tank 8. The water tank inlet pipe 81 is used to allow undissolved gas discharged from the ammonia tank vent pipe 55 to enter the water storage tank 8. The undissolved gas mixes with water... A secondary dissolution process is performed to improve the ammonia recovery rate. The dissolved mixed water (i.e., water containing dissolved ammonia) is discharged from the water storage tank return pipe 82, and after passing through the return control valve 10, it returns and enters the super ammonia absorber 2 and the ammonia tank 5 respectively. One of the return paths to the ammonia tank 5 is connected to the ammonia tank inlet pipe 51; the other return path to the super ammonia absorber 2 is connected to the ammonia tank return pipe 54, specifically connected to the ammonia tank return pipe 54 between the super ammonia absorber 2 and the ammonia return check valve 542.

[0054] The exhaust pipe 83 of the water storage tank discharges the gas after secondary dissolution to the exhaust gas purifier 9, and after purification, it is directly released into the air; the drain pipe 84 of the water storage tank discharges the water in the water storage tank 8 as demineralized water for reuse.

[0055] In implementation, multiple water tank return pipes 82 are used, and these multiple water tank return pipes 82 are connected in parallel between the water tank 8 and the return control valve 10. Multiple water tank return pipes 82 not only improve the return speed of the dissolved mixed water in the water tank 8, but also serve as backups to prevent the system from shutting down if one of the water tank return pipes 82 fails.

[0056] Preferably, there are two water tank return pipes 82, which are connected in parallel. Each water tank return pipe 82 is equipped with a return filter 821, a return conveying pump 822, and a return check valve 823 along the flow direction of the material.

[0057] Preferably, the return filter 821 is a Y-type filter used to filter impurities in the mixed water to prevent them from entering the super ammonia absorber 2 and the ammonia tank 5; the return check valve 823 can prevent ammonia from flowing back into the storage tank 8.

[0058] In this invention, the main component of the alkaline gas after treatment of semi-coke organic wastewater is ammonia. Ammonia is highly soluble in water. The ammonia in the alkaline gas is dissolved and diluted using circulating water to form a 20% ammonia solution, which is then sent to the boiler denitrification section 7 to replace the existing denitrification agent. This reduces the purchase cost of the 20% ammonia solution and solves the problems of waste gas treatment costs and secondary environmental pollution caused by organic wastewater, thereby lowering the company's operating costs. After the alkaline gas reuse system for semi-coke organic wastewater treatment provided by this invention is put into operation, it can reduce the purchase of approximately 5.5 tons of ammonia solution per day. With ammonia solution priced at 1325 yuan / ton, this translates to annual savings of 2.4048 million yuan. It also solves the problem of secondary environmental pollution and treatment costs caused by alkaline gases from organic wastewater; furthermore, it is stable in operation, convenient to use, and low in cost.

[0059] The above description is merely an embodiment of this utility model and does not limit the patent scope of this utility model. Any equivalent structural or procedural transformations made based on the description and drawings of this utility model, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of this utility model.

Claims

1. A system for recycling alkaline gas after treatment of organic waste water from a blue water gas, characterized by, The system comprises an alkaline gas conveying pipe (1), a super ammonia absorber (2), a circulating water inlet pipe (3), a circulating water outlet pipe (4), an ammonia water tank (5) and a boiler denitration section (7); the alkaline gas conveying pipe (1), the super ammonia absorber (2), the ammonia water tank (5) and the boiler denitration section (7) are sequentially communicated, and the circulating water inlet pipe (3) is communicated with the circulating water outlet pipe (4) through the super ammonia absorber (2).

2. The system according to claim 1, wherein the system is characterized by, A flow meter (101) and an alkaline gas filter (102) are sequentially arranged on the alkaline gas conveying pipe (1) along the conveying direction.

3. The system according to claim 1, wherein the system is characterized by, A circulating water inlet control valve (301) and a circulating water filter (302) are sequentially arranged on the circulating water inlet pipe (3) along the water flow direction.

4. The system according to claim 1, wherein the system is characterized by, A circulating water outlet control valve (401) is arranged on the circulating water outlet pipe (4).

5. The system according to any one of claims 1 to 4, wherein the system is characterized by, The system further comprises an ammonia water inlet valve (6) arranged between the ammonia water tank (5) and the boiler denitration section (7).

6. The system according to claim 5, wherein the system is characterized by, An ammonia water tank inlet pipe (51), an ammonia water tank overflow pipe (52), an ammonia water tank outlet pipe (53) and an ammonia water tank return pipe (54) are sequentially communicated on the outer wall of the ammonia water tank (5) from top to bottom; the ammonia water tank inlet pipe (51) is communicated with the bottom of the super ammonia absorber (2), the ammonia water tank outlet pipe (53) is communicated with the boiler denitration section (7) through the ammonia water inlet valve (6), the ammonia water tank overflow pipe (52) is communicated with the boiler denitration section (7) through the ammonia water inlet valve (6), and one end of the ammonia water tank return pipe (54) is communicated with the ammonia water tank (5) through the ammonia water tank outlet pipe (53), and the other end of the ammonia water tank return pipe (54) is communicated with the upper side wall of the super ammonia absorber (2).

7. The system according to claim 6, wherein the system is characterized by, An ammonia water filter (531), an ammonia water conveying pump (532) and an ammonia water check valve (533) are sequentially arranged on the ammonia water tank outlet pipe (53) along the material flow direction.

8. The system according to claim 6, wherein the system is characterized by, The system further comprises a tail gas purifier (9); the top of the ammonia water tank (5) is externally connected with an ammonia water tank exhaust pipe (55), and the ammonia water tank (5) is communicated with the tail gas purifier (9) through the ammonia water tank exhaust pipe (55).

9. The system according to claim 8, wherein the system is characterized by, The system further comprises a water storage tank (8) arranged between the ammonia water tank exhaust pipe (55) and the tail gas purifier (9); the water storage tank (8) is further communicated with the super ammonia absorber (2) and the ammonia water tank (5).

10. The system according to claim 9, wherein the system is characterized by, The system further comprises a return material control valve (10); the water storage tank (8) is communicated with the super ammonia absorber (2) and the ammonia water tank (5) through the return material control valve (10).

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