Wastewater treatment device in production of semi-coke

Abstract

This application provides a wastewater treatment device for semi-coke production, including a boiler. The boiler furnace is connected to an ammonia water pipeline in front of the boiler via multiple spray guns. The ammonia water pipeline in front of the boiler is sequentially connected to an ammonia water pump, a wastewater intermediate tank, and a wastewater pool. An ammonia water main valve is installed between the ammonia water pipeline in front of the boiler and the ammonia water pump. A spray gun valve is installed between the spray guns and the ammonia water pipeline in front of the boiler. This device, through the above-mentioned equipment configuration, incinerates the wastewater from semi-coke production, overcoming the drawbacks of existing conventional methods for treating coking wastewater, such as high cost, high treatment difficulty, and poor treatment effect.

Description

Technical Field

[0001] This application relates to the field of wastewater treatment technology, and in particular to a wastewater treatment device for semi-coke production. Background Technology

[0002] Semi-coke, also known as semi-coke, is a low-volatile solid carbonaceous product obtained by dry distilling non-caking or weakly caking high-volatile bituminous coal under medium- and low-temperature conditions, releasing coal tar and coal gas. It possesses excellent characteristics such as high fixed carbon, high resistivity, high reactivity, high calorific value, and extremely low sulfur, aluminum, and phosphorus content. Semi-coke has a wide range of applications, serving as a raw material in industries such as metallurgy, calcium carbide, fertilizer, and activated carbon, and can also be used as a clean fuel in clean production. Semi-coke wastewater mainly originates from the residual circulating ammonia water obtained from the low-temperature dry distillation and coal gas purification process during semi-coke production, and from the industrial wastewater formed during the steam quenching of semi-coke. Semi-coke wastewater is reddish-brown in appearance and contains high concentrations of inorganic pollutants such as COD, cyanide, and ammonia nitrogen, as well as organic pollutants such as benzene and phenols. Because the dry distillation temperature of semi-coke is much lower than that of coke production, incomplete oxidation of coal occurs during the semi-coke production process, resulting in concentrations of some pollutants in semi-coke wastewater that are approximately 10 times higher than in ordinary coking wastewater.

[0003] Existing treatment methods for semi-coke wastewater mainly draw on the experience of coking wastewater treatment, which involves pre-treating semi-coke wastewater through oil removal and then subjecting it to conventional wastewater treatment such as biochemical or oxidation treatment. However, even after pre-treatment, the concentrations of COD (chemical oxygen demand) and NH3-N (ammonia nitrogen) in the semi-coke wastewater remain very high. The aforementioned conventional treatment methods are not only costly but also difficult to implement and cannot bring the wastewater to a qualified level. Utility Model Content

[0004] This application provides a wastewater treatment device for semi-coke production, which solves the problems of high cost, high treatment difficulty and poor treatment effect when using existing conventional coking wastewater treatment methods to treat semi-coke wastewater.

[0005] This application provides a wastewater treatment device for semi-coke production, including a boiler. The furnace of the boiler is connected to an ammonia water pipeline in front of the furnace through multiple spray guns. The ammonia water pipeline in front of the furnace is connected in sequence to an ammonia water pump, a wastewater intermediate tank and a wastewater pool.

[0006] A main ammonia valve is installed between the ammonia water pipeline in front of the furnace and the ammonia water pump.

[0007] A spray gun valve is installed between the spray gun and the ammonia water pipeline in front of the furnace.

[0008] Optionally, multiple spray guns are symmetrically distributed on both sides of the boiler furnace and are introduced into the furnace through the secondary air inlet in the middle of the boiler.

[0009] Optionally, the number of spray guns on each side of the boiler is 2 to 4.

[0010] Optionally, the ammonia pump and the main ammonia valve are connected to the wastewater tank via a drain valve.

[0011] Optionally, multiple spray guns are also connected to compressed air lines via purge valves.

[0012] Optionally, a heat exchanger is also installed between the ammonia pump and the main ammonia valve;

[0013] The heat exchanger is located in the flue.

[0014] Optionally, the boiler is a fluidized bed boiler.

[0015] This application provides a wastewater treatment device for semi-coke production. An ammonia pump transfers the semi-coke production wastewater from the intermediate wastewater tank into the ammonia water pipeline before the furnace. The wastewater is then distributed to spray guns via the ammonia water pipeline, and the spray guns atomize the wastewater and inject it into the boiler furnace for combustion. The high temperature inside the furnace causes the water in the wastewater to react with the hot, incompletely burned coke in a water-gas chemical reaction, generating carbon monoxide and hydrogen for combustion. Simultaneously, the ammonia nitrogen compounds in the wastewater undergo a redox reaction with the nitrogen oxides generated in the furnace at high temperatures, achieving denitrification. This reduces the use of denitrification agents and saves production costs. The device of this application, using the aforementioned equipment configuration, treats wastewater from semi-coke production, overcoming the drawbacks of existing conventional coking wastewater treatment methods, such as high cost, high treatment difficulty, and poor treatment effect. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 A schematic diagram of a wastewater treatment device in semi-coke production provided in an embodiment of this application;

[0018] Figure 2 A top view of the layout of the spray gun inside the furnace according to an embodiment of this application;

[0019] Figure 3 This is a schematic diagram of a wastewater treatment device in semi-coke production provided in another embodiment of this application;

[0020] Figure 4 A schematic diagram of a wastewater treatment device for semi-coke production provided in yet another embodiment of this application;

[0021] Figure 5 This is a schematic diagram of a wastewater treatment device in semi-coke production provided in another embodiment of this application.

[0022] Explanation of reference numerals in the attached figures:

[0023] 1. Boiler; 2. Spray gun; 3. Wastewater intermediate tank; 4. Wastewater pool; 5. Heat exchanger; 10. Ammonia water pipeline; 11. Flue; 20. Ammonia water pump; 30. Compressed air pipeline; 100. Ammonia water main valve; 200. Spray gun valve; 300. Drain valve; 400. Purge valve. Detailed Implementation

[0024] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions in the embodiments of this application are described clearly and completely below. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are also within the scope of protection of this application.

[0025] The semi-coke production process generates a portion of colored, oily ammonia water, which cannot be recycled. Given the high cost of wastewater treatment, and based on the principles of boiler combustion and denitrification in power plants, a low-NOx combustion modification using steam atomization is implemented. The red ammonia water enters the furnace and reacts with the hot, incompletely burned coke in a water-gas chemical reaction, producing carbon monoxide and hydrogen. By spraying a water mist jet of semi-coke ammonia water at appropriate locations in the reduction zone, low-NOx combustion of water-gas is achieved, significantly reducing the amount of ammonia water used in boiler denitrification while simultaneously treating the red ammonia wastewater from the semi-coke production.

[0026] like Figure 1 As shown, this application provides a wastewater treatment device for semi-coke production, including a boiler 1. The furnace of the boiler 1 is connected to an ammonia water pipeline 10 in front of the furnace through multiple spray guns 2. The ammonia water pipeline 10 in front of the furnace is connected in sequence to an ammonia water pump 20, a wastewater intermediate tank 3 and a wastewater pool 4.

[0027] A main ammonia valve 100 is installed between the ammonia water pipeline 10 in front of the furnace and the ammonia water pump 20.

[0028] A spray gun valve 200 is installed between the spray gun 2 and the ammonia water pipeline 10 in front of the furnace.

[0029] In operation, the wastewater in wastewater tank 4 (which has already undergone oil removal but has a high ammonia nitrogen content) is transferred to intermediate wastewater tank 3 for later use. When treating the wastewater, the main ammonia valve 100 and the spray gun valve 200 are opened, and the ammonia pump 20 is started to draw the wastewater from intermediate wastewater tank 3. The wastewater is then distributed through the main ammonia valve 100 to the ammonia pipes 10 on both sides of the boiler, and subsequently supplied to the spray gun 2 through the spray gun valve 200. The atomized wastewater is then sprayed out through the spray gun 2 and atomized. This atomized wastewater, along with secondary air, enters the furnace and undergoes a water-gas chemical reaction with the hot, incompletely burned coke, generating carbon monoxide and hydrogen. A semi-coke ammonia water mist jet is sprayed at an appropriate location in the reduction zone (i.e., the location of the spray gun 2 in this application), thus achieving low-NOx combustion of water-gas, significantly saving the amount of ammonia water used for boiler denitrification, and simultaneously treating the semi-coke red ammonia wastewater.

[0030] The ammonia water from the semi-coke coking furnace is delivered to the semi-coke operation station (plant) via the Ø133 semi-coke ammonia water conveying pipeline, and then introduced into the fluidized bed boiler 8 meters in front of the furnace through the Ø50 pipeline and valve group. It branches to ammonia water atomizing spray guns 2 on both sides of the furnace, and enters the secondary air inlets in the middle of the furnace (two on each side, front and rear spray guns). With the help of the secondary air, it is mixed and sent into the furnace for combustion. The high-ammonia nitrogen wastewater enters the fluidized bed furnace and undergoes a water-gas chemical reaction with the hot, incompletely burned coke, producing carbon monoxide and hydrogen. This process absorbs some heat and also produces water gas for combustion. Simultaneously, due to the high ammonia nitrogen content in the wastewater, these ammonia nitrogen compounds act as a reducing agent for nitrogen oxides produced during fuel combustion. Under high-temperature conditions, they undergo a redox reaction with the nitrogen oxides produced during combustion, reducing the nitrogen oxides to nitrogen gas, achieving a low-nitrogen denitrification effect through aerosol. This effectively saves on the use of denitrification agents (urea, ammonia water, or liquid ammonia) in the SNCR denitrification process of boiler 1.

[0031] In one alternative embodiment, the oil removal ammonia water plate of the semi-coke coking furnace is pressurized to 0.5 MPa by the ammonia water pump 20, and then transported to the ammonia water pipeline 10 in front of the furnace through the semi-coke ammonia water conveying pipeline Ø133 (that is, the pipeline connecting the ammonia water pipeline 10 in front of the furnace and the ammonia water pump 20).

[0032] In this application, the total flow rate of the spray gun 2 is 1000 kg / h, and it is connected to the spray gun valve 200 (DN20) via a metal hose and then inserted into the DN65 secondary air inlet.

[0033] This application provides a wastewater treatment device for semi-coke production. An ammonia pump 20 transfers the semi-coke production wastewater from the intermediate wastewater tank 3 into the furnace front ammonia pipeline 10. The wastewater is then distributed to spray guns 2 via the furnace front ammonia pipeline 10, and atomized and sprayed into the furnace of the boiler 1 for combustion. The high temperature within the furnace causes the water in the wastewater to undergo a water-gas chemical reaction with the hot, incompletely burned coke, generating carbon monoxide and hydrogen for combustion. Simultaneously, the ammonia nitrogen compounds in the wastewater undergo an oxidation-reduction reaction with the nitrogen oxides generated in the furnace at high temperatures, achieving denitrification. This reduces the use of denitrification agents, resulting in cost savings. The device of this application, using the aforementioned equipment, treats wastewater from semi-coke production, overcoming the drawbacks of existing conventional coking wastewater treatment methods, such as high cost, high treatment difficulty, and poor treatment effect.

[0034] Optionally, multiple spray guns 2 are symmetrically distributed on both sides of the furnace of boiler 1 and are introduced into the furnace through the secondary air inlet in the middle of boiler 1.

[0035] In this application, the secondary air inlet is a core air supply component of the boiler system in a thermal power plant, which is injected into the furnace at high speed through layers above the grate or the burner. Its main functions are to supplement the oxygen required for pulverized coal combustion, improve flue gas mixing efficiency, and form an "air-enveloping-pulverized-coal" flame structure through swirl design, thereby inhibiting coking and improving combustion stability.

[0036] Secondary air inlets are typically arranged in multiple layers. In low-NOx combustion, the proper layout and air supply angle of the secondary air inlets effectively reduce the oxygen concentration in the main combustion zone, thereby reducing NOx formation. In this application, multiple layers of secondary air inlets are arranged, with the middle layer referring to the secondary air inlets in the vertical direction. The spray gun 2 guides the wastewater into the furnace from the middle secondary air inlets. This allows the injected wastewater to contact and react with the incompletely burned fuel (i.e., pulverized coal) to generate carbon monoxide and hydrogen. At the same time, the area corresponding to the middle secondary air inlets has sufficient temperature to allow the ammonia nitrogen in the wastewater to react with the nitrogen oxides produced during combustion.

[0037] like Figure 2 As shown, optionally, there are 2 to 4 spray guns on each side of the boiler.

[0038] In this application, there are two spray guns on each side, which are arranged close to the front and back walls to avoid uneven spraying of wastewater caused by concentrated distribution.

[0039] like Figure 3 As shown, optionally, the ammonia pump 20 and the ammonia main valve 100 are connected to the wastewater tank 4 via a drain valve 300.

[0040] In this application, when it is necessary to inspect and repair the pipelines in the device, the main ammonia valve 100 needs to be closed and the drain valve 300 needs to be opened. The wastewater in the intermediate wastewater tank 3 is completely discharged into the wastewater pool 4 through the ammonia pump 20, so that the pipelines are in a waterless state before the pipeline inspection and maintenance work is carried out.

[0041] like Figure 4 As shown, optionally, multiple spray guns 2 are also connected to compressed air lines 30 via purge valves 400.

[0042] In this application, when maintenance is required on the spray gun 2 and the ammonia water pipeline 10 in front of the furnace, the main ammonia water valve 100 is closed, the purge valve 400 is opened, and the compressed air in the compressed air pipeline 30 is supplied to the spray gun 2 through the purge valve 400 to purge and clean the spray gun 2 and its interior.

[0043] like Figure 5 As shown, optionally, a heat exchanger 5 is also provided between the ammonia pump 20 and the ammonia main valve 100;

[0044] Heat exchanger 5 is installed in flue 11.

[0045] In this application, the ammonia water pump 20 is started to draw the wastewater from the intermediate wastewater tank 3 and transfer it to the heat exchanger 5. The wastewater is heated by exchanging heat with the flue gas in the flue through the heat exchanger 5 (temperature is about 80~90℃). The heated wastewater is then distributed to the ammonia water pipelines 10 on both sides of the boiler through the ammonia water main valve 100.

[0046] In this application, because the wastewater temperature is relatively low, if it is not preheated, when it is sent into the furnace along with secondary air, it will absorb heat from the furnace, causing a significant drop in local temperature within the furnace and resulting in incomplete combustion of fuel in certain areas, thus leading to fuel waste. In this application, by preheating the wastewater to a certain temperature using a preheater, the heat absorption of the wastewater into the furnace can be reduced, thereby reducing the aforementioned fuel waste caused by incomplete combustion of fuel in certain areas. Furthermore, this application utilizes the heat from the flue gas duct for heating, effectively utilizing the waste heat of the flue gas, and has the characteristic of saving energy.

[0047] It should be noted that in this application, the heat exchanger 5 is installed near the flue outlet (in this application, the heat exchanger 5 is a structure formed by coiling heat exchange tubes, which is similar to the coiled and folded state of an economizer). Generally, after the flue gas passes through the air preheater in the flue, it needs to be dusted before being sent to the desulfurization unit for desulfurization. However, the temperature of the flue gas is still relatively high near the air preheater. If heat exchange is performed at this time, it is easy to cause the wastewater to overheat and put a lot of pressure on the pipeline. Therefore, in this application, the preheater is set in the flue between the dust collector and the desulfurization unit. This not only avoids the wastewater from overheating, but also reduces the corrosion of the heat exchange tubes by the dust in the flue gas and the accumulation of dust on the heat exchange tubes.

[0048] Optionally, boiler 1 is a fluidized bed boiler.

[0049] Example 1

[0050] A wastewater treatment device for semi-coke production, the working process of which is as follows:

[0051] During use, the wastewater in wastewater tank 4 (which has already been de-oiled but has a high ammonia nitrogen content) is transferred to intermediate wastewater tank 3 for later use. When treating the wastewater, the main ammonia valve 100 and the spray gun valve 200 should be opened, the drain valve 300 and the purge valve 400 should be closed, and the ammonia pump 20 should be started to draw the wastewater from the intermediate wastewater tank 3 into the heat exchanger 5. The wastewater will be heated by exchanging heat with the flue gas in the flue (temperature approximately 80-90°C) through the heat exchanger 5. The heated wastewater will be distributed to the ammonia pipes 10 on both sides of the boiler through the main ammonia valve 10, and then supplied to the spray gun 2 through the spray gun valve 200. The atomized wastewater will then be sprayed out through the spray gun 2 and atomized. This atomized wastewater will enter the furnace along with the secondary air and react with the hot, incompletely burned coke to produce carbon monoxide and hydrogen. By spraying a water mist jet of semi-coke ammonia water at an appropriate location in the reduction zone (i.e., the location of spray gun 2 in this application), low-NOx combustion of water gas is achieved, which can significantly save the amount of ammonia water used for boiler denitrification. At the same time, semi-coke red ammonia wastewater is treated.

[0052] When it is necessary to inspect and maintain the pipelines in the unit, the main ammonia valve 100 should be closed and the drain valve 300 should be opened. The wastewater in the intermediate wastewater tank 3 should be completely discharged into the wastewater pool 4 through the ammonia pump 20, so that the pipelines are in a water-free state before the pipeline inspection and maintenance work can be carried out.

[0053] Example 2

[0054] A wastewater treatment device for semi-coke production, the working process of which is as follows:

[0055] During use, the wastewater in wastewater tank 4 (which has already been de-oiled but has a high ammonia nitrogen content) is transferred to intermediate wastewater tank 3 for later use. When treating the wastewater, the main ammonia valve 100 and the spray gun valve 200 should be opened, the drain valve 300 and the purge valve 400 should be closed, and the ammonia pump 20 should be started to draw the wastewater from the intermediate wastewater tank 3 into the heat exchanger 5. The wastewater will be heated by exchanging heat with the flue gas in the flue (temperature approximately 80-90°C) through the heat exchanger 5. The heated wastewater will be distributed to the ammonia pipes 10 on both sides of the boiler through the main ammonia valve 10, and then supplied to the spray gun 2 through the spray gun valve 200. The atomized wastewater will then be sprayed out through the spray gun 2 and atomized. This atomized wastewater will enter the furnace along with the secondary air and react with the hot, incompletely burned coke to produce carbon monoxide and hydrogen. By spraying a water mist jet of semi-coke ammonia water at an appropriate location in the reduction zone (i.e., the location of spray gun 2 in this application), low-nitrogen combustion of water gas is achieved, which can significantly save the amount of denitrification ammonia water used in the boiler, and at the same time treat the semi-coke red ammonia wastewater.

[0056] When maintenance is required on the spray gun 2 and the ammonia water pipeline 10 in front of the furnace, close the main ammonia water valve 100, open the purge valve 400, and supply the compressed air in the compressed air pipeline 30 to the spray gun 2 through the purge valve 400 to purge and clean the spray gun 2 and its interior.

[0057] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A device for treating waste water in production of blue water, characterized in that, The application relates to a boiler (1), a hearth of the boiler (1) is connected with a front ammonia water pipeline (10) through a plurality of spray guns (2), the front ammonia water pipeline (10) is sequentially connected with an ammonia water pump (20), a waste water intermediate tank (3) and a waste water pool (4); An ammonia water total valve (100) is arranged between the front ammonia water pipeline (10) and the ammonia water pump (20); A spray gun valve (200) is arranged between the spray gun (2) and the front ammonia water pipeline (10).

2. The apparatus for treating waste water in production of blue water according to claim 1, wherein, The plurality of spray guns (2) are symmetrically distributed on both sides of the hearth of the boiler (1) and are input into the hearth through a secondary air inlet in the middle of the boiler (1).

3. The apparatus for treating waste water in production of blue water according to claim 2, wherein The number of the spray guns (2) on each side of the boiler is 2-4.

4. The apparatus for treating waste water in production of blue water according to claim 1, wherein, The ammonia water pump (20) is connected with the waste water pool (4) through a blowdown valve (300) and the ammonia water total valve (100).

5. The apparatus for treating waste water in production of blue water according to claim 1, wherein, The plurality of spray guns (2) are further connected with a compressed air pipeline (30) through a purge valve (400).

6. The apparatus for treating waste water in production of blue water according to claim 1, wherein, A heat exchanger (5) is further arranged between the ammonia water pump (20) and the ammonia water total valve (100); The heat exchanger (5) is arranged in a flue (11).

7. The apparatus for treating waste water in production of blue water according to any one of claims 1 to 6, wherein The boiler (1) is a fluidized bed boiler.

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