Self-cleaning spraying type saturator and operation method

Abstract

The invention provides a self-cleaning spraying type saturator and an operation method. The self-cleaning spraying type saturator comprises an annular spraying pipe, an annular spraying pipe support, an ammonia water mother liquor heat exchanger and a cleaning connector. The annular spraying pipe is made of a 316L stainless steel pipe with the diameter of 65 mm, the annular spraying pipe is connected into two semicircular rings through flanges, the diameter of the annular spraying pipe is 2000 mm, and 16 spraying holes and evenly-distributed nozzles are formed in the annular spraying pipe. And the bracket is welded at a position 30-40mm away from the bottom of the saturator for fixing. The heat exchanger is made of 316L stainless steel, the heat exchange area is 200 m < 3 >, and the heat exchanger is connected to an outlet pipeline of the crystallization pump through a three-way pipeline and a valve. High-temperature ammonia distillation wastewater enters the heat exchanger, mother liquor exchanges heat with the wastewater, the high-temperature mother liquor is used for washing ammonium sulfate accumulated at the bottom of the saturator, meanwhile, the flow and angle of a nozzle can be adjusted through an intelligent nozzle flow adjusting device, and the flow and flow velocity of the ammonia distillation wastewater and the mother liquor are adjusted based on feedback data of a heat exchange efficiency monitoring sensor. And normal production of the saturator is recovered.

Description

Technical Field

[0001] The present invention relates to the technical field of coal soot denitrification equipment, and more particularly to a self-cleaning spray saturator and an operation method thereof. Background Art

[0002] The ammonia content in the raw coke oven gas is generally 2-6 g / m3. This part of ammonia needs to be removed in the gas purification process. Otherwise, the ammonia in the gas will corrode the gas equipment and facilities and seriously affect the normal production of the subsequent crude benzene process.

[0003] At present, the ammonia removal from coke oven gas mainly adopts the saturator method to produce ammonium sulfate. The specific process is as follows: The gas from the desulfurization tower and the ammonia gas at 85°C - 90°C from the ammonia distillation tower enter the saturator through the central duct. Among them, NH3 reacts with the free acid to produce ammonium sulfate, and the reaction formula is 2NH3 + H2SO4 → (NH4)2SO4. The remaining components leave the saturator and are sent to the gas pipeline. In the saturator, the ammonium sulfate mother liquor is stirred by a large circulation pump to make the ammonium sulfate crystals precipitated at the bottom of the saturator in a suspended state to facilitate the growth of the crystals. With the continuous production of ammonium sulfate, when the crystal ratio reaches 30%, the crystals are sent to the crystallization tank by a crystallization pump. The large-particle crystals enter the centrifuge, and the small-particle crystals together with the mother liquor are returned to the saturator through the reflux tank. The wet ammonium sulfate from the centrifuge is sent to the drying cooler by a screw conveyor. The ammonium sulfate dried by air is sent to the storage hopper by a screw conveyor. After the ammonium sulfate is weighed and packaged, it is sent to the ammonium sulfate warehouse for storage and sale by a forklift.

[0004] The saturator is the main equipment for ammonium sulfate production. In actual production, due to the influence of operating conditions and temperature, ammonium sulfate often accumulates at the bottom of the saturator. Seriously, the mother liquor will block the central gas duct of the saturator, which not only affects the normal production of the saturator but also affects the normal gas transmission. The commonly used treatment method is to stop the production of the saturator, wash the accumulated ammonium sulfate inside the saturator by heating and adding water to the bottom of the saturator and venting at the bottom vent point. If the situation is serious, it is necessary to block the gas blind plate and personnel clean the bottom of the saturator. Summary of the Invention

[0005] In view of the above technical problems, a self-cleaning spray saturator and an operation method thereof are provided. Based on the annular spray pipe, the present invention solves the problem that the ammonium sulfate accumulates at the bottom of the spray saturator without stopping production, which affects the normal production of the saturator.

[0006] To achieve the above object, the present invention provides a self-cleaning spray saturator, including: an annular spray pipe, an annular spray pipe support, an ammonia mother liquor heat exchanger, and a cleaning interface;

[0007] Annular spray pipe, the annular spray pipe is made of 316L stainless steel pipe with a diameter of Φ65mm, the diameter is smaller than the bottom diameter of the saturator, and there are 16 spray holes with a diameter of Φ15mm in two upper and lower rows on the annular spray pipe, and nozzles are welded on the holes;

[0008] Annular spray pipe support, the support is welded at 30 - 40mm from the bottom of the saturator, and is used to fix the annular spray pipe;

[0009] Ammonia mother liquor heat exchanger, the heat exchanger is made of 316L stainless steel material, and the heat exchange area is 200m 3 , and is used to exchange heat between the high-temperature ammonia distillation wastewater under the ammonia distillation tower and the mother liquor at the outlet of the crystallization pump;

[0010] Cleaning interface, the cleaning interface is connected to the ammonia mother liquor heat exchanger through a 316L stainless steel pipe with a diameter of DN65, and is used to introduce high-temperature mother liquor into the bottom of the saturator for flushing.

[0011] Furthermore, the annular spray pipe is connected into two semi-circular rings through flanges, the diameter of the annular spray pipe is 2000mm, and the nozzles on the annular spray pipe are evenly distributed to ensure that the high-temperature mother liquor can be evenly sprayed on the bottom of the saturator.

[0012] Furthermore, the ammonia mother liquor heat exchanger is connected to the pipeline at the outlet of the crystallization pump through a tee pipeline and a valve, and is used to exchange heat between the high-temperature ammonia distillation wastewater and the mother liquor at the outlet of the crystallization pump to increase the temperature of the mother liquor.

[0013] The present invention also provides an operation method for a self-cleaning spray saturator, including the following steps:

[0014] S1. Open the inlet valve and outlet valve of the ammonia distillation wastewater, so that the 90°C high-temperature ammonia distillation wastewater enters the ammonia mother liquor heat exchanger;

[0015] S2. Open the inlet valve for the mother liquor to enter the heat exchanger, and close the valve for the mother liquor to the crystallization tank, so that the mother liquor at the outlet of the crystallization pump exchanges heat with the high-temperature ammonia distillation wastewater;

[0016] S3. The temperature of the mother liquor at the outlet of the crystallization pump continuously rises, and the high-temperature mother liquor is continuously sprayed through the annular spray pipe to flush the ammonium sulfate accumulated at the bottom of the saturator;

[0017] S4. Utilize the principle that the solubility of ammonium sulfate increases with the increase in the temperature of the mother liquor to dissolve all the accumulated ammonium sulfate and restore the normal production of the saturator.

[0018] Furthermore, in S3, by using an intelligent nozzle flow regulating device, according to the information fed back by the ammonium sulfate accumulation detection system at the bottom of the saturator, the flow rate and angle of the nozzle are adjusted in real time, and the bottom of the saturator is flushed periodically, and each period is not less than 30 minutes to ensure that there is no ammonium sulfate accumulation at the bottom of the saturator.

[0019] Furthermore, based on the data feedback from the heat exchange efficiency monitoring sensor, when the heat exchange efficiency is lower than the set threshold, the flow rate and velocity of the ammonia distillation wastewater and the mother liquor are automatically adjusted to maintain the efficient operation of the heat exchange.

[0020] Due to the adoption of the above technical solution, compared with the prior art, the present invention has the following advantages:

[0021] 1. The self-cleaning spray saturator and operation method provided by the present invention can solve the problem that the ammonium sulfate accumulates at the bottom of the spray saturator without stopping production, which affects the normal production of the saturator.

[0022] 2. The self-cleaning spray saturator and operation method provided by the present invention can reduce the temperature of the 90°C high-temperature ammonia distillation wastewater after ammonia distillation and reduce the partial heat load of the circulating water for cooling the high-temperature ammonia distillation wastewater.

[0023] 3. The self-cleaning spray saturator and operation method provided by the present invention can be used as an auxiliary heating device for the mother liquor, and jointly heat the mother liquor of the saturator with the gas preheater to ensure that the temperature of the mother liquor is above 55°C and stabilize the yield of ammonium sulfate produced by the saturator method.

[0024] Based on the above reasons, the present invention can be widely promoted in the technical field of coal smoke denitrification equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0026] Figure 1 It is a schematic structural diagram of a self-cleaning spray saturator described in the present invention;

[0027] Figure 2 It is a schematic structural diagram of an annular spray pipe of a self-cleaning spray saturator described in the present invention;

[0028] Figure 3 It is a flow chart of the operation method of a self-cleaning spray saturator described in the present invention.

[0029] In the figure: 1. Secondary spraying mother liquor pump; 2. Full chute; 3. Vent pipe; 4. Annular spraying device; 5. Crystallization pump; 6. Mother liquor circulation pump; 7. Saturator spray box; 8. Gas outlet; 9. Gas inlet; 10. Overflow pipe; 11. Ammonia mother liquor heat exchanger; 12. Mother liquor inlet valve to heat exchanger; 13. Mother liquor to crystallization tank valve; 14. Residual ammonia inlet valve to heat exchanger; 15. Residual ammonia heat exchanger outlet valve; 16. Connecting flange; 17. Spraying hole. DETAILED DESCRIPTION

[0030] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0031] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is by no means intended to limit the present invention and its application or use. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0032] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit exemplary embodiments according to the present invention. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprising" and / or "including" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0033] Unless otherwise specifically stated, the relative arrangement of the parts and steps described in these embodiments, the numerical expressions and numerical values do not limit the scope of the present invention. At the same time, it should be clear that, for ease of description, the sizes of the various parts shown in the drawings are not drawn according to the actual proportional relationship. The technology, methods and equipment known to ordinary technicians in the relevant field may not be discussed in detail, but in appropriate cases, the technology, methods and equipment should be regarded as part of the authorization specification. In all examples shown and discussed here, any specific value should be interpreted as merely exemplary, rather than as a limitation. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar numbers and letters represent similar items in the following drawings, so once an item is defined in one drawing, it does not need to be further discussed in subsequent drawings.

[0034] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by orientation terms such as "front, rear, upper, lower, left, right", "lateral, vertical, perpendicular, horizontal" and "top, bottom", etc. is usually based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description. Without contrary explanation, these orientation terms do not indicate and imply that the device or component referred to must have a specific orientation or be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation on the protection scope of the present invention: the orientation terms "inner, outer" refer to the inside and outside relative to the contour of each component itself.

[0035] For the convenience of description, spatial relative terms such as "above...", "over...", "on the upper surface of...", "above-mentioned", etc. can be used here to describe the spatial positional relationship between a device or feature shown in the drawings and other devices or features. It should be understood that the spatial relative terms are intended to include different orientations in use or operation in addition to the orientation described in the drawings for the device. For example, if the device in the drawing is inverted, the device described as "above other devices or structures" or "over other devices or structures" will then be positioned as "below other devices or structures" or "under other devices or structures". Thus, the exemplary term "above..." can include both the orientations of "above..." and "below...". The device can also be positioned in other different ways (rotated 90 degrees or in other orientations), and corresponding explanations are made for the spatial relative descriptions used here.

[0036] In addition, it should be noted that the use of words such as "first", "second", etc. to limit components is only for the convenience of differentiating the corresponding components. Without separate statement, the above words have no special meaning. Therefore, it should not be construed as a limitation on the protection scope of the present invention.

[0037] As Figures 1 to 2 shown, a self-cleaning spray saturator of the present invention includes: an annular spray pipe, an annular spray pipe bracket, an ammonia mother liquor heat exchanger 11, and a cleaning interface;

[0038] The annular spray pipe is made of 316L stainless steel pipe with a diameter of Φ65mm, and its diameter is smaller than the diameter of the bottom of the saturator. There are 16 spray holes 17 in two rows, upper and lower, with a diameter of Φ15mm on the annular spray pipe, and nozzles are welded on the holes;

[0039] The annular spray pipe bracket is welded at 30 - 40mm from the bottom of the saturator and is used to fix the annular spray pipe;

[0040] The ammonia mother liquor heat exchanger 11 is made of 316L stainless steel material, and the heat exchange area is 200m 3, for heat exchange between the high-temperature ammonia-steaming wastewater under the ammonia-steaming tower and the mother liquor at the outlet of the crystallization pump 5;

[0041] A cleaning interface, which is connected to the ammonia-water mother liquor heat exchanger 11 through a 316L stainless steel pipe with a DN65, for introducing the high-temperature mother liquor into the bottom of the saturator for flushing.

[0042] Furthermore, the annular spraying pipe is connected into two semi-circular rings through a connecting flange 16. The diameter of the annular spraying pipe is 2000 mm, and the nozzles on the annular spraying pipe are evenly distributed to ensure that the high-temperature mother liquor can be evenly sprayed on the bottom of the saturator.

[0043] Furthermore, the ammonia-water mother liquor heat exchanger 11 is connected to the outlet pipe of the crystallization pump 5 through a tee pipe and a valve, for heat exchange between the high-temperature ammonia-steaming wastewater and the mother liquor at the outlet of the crystallization pump 5 to increase the temperature of the mother liquor.

[0044] Furthermore, as Figure 3 shown, during the operation of the saturator, when it is detected that there is ammonium sulfate accumulation at the bottom of the saturator, start the cleaning operation of the self-cleaning spray-type saturator. First, open the inlet valve and outlet valve of the ammonia-steaming wastewater, so that the 90°C high-temperature ammonia-steaming wastewater from the ammonia-steaming tower enters the ammonia-water mother liquor heat exchanger 11. At the same time, open the inlet valve for the mother liquor to enter the heat exchanger and close the valve for the mother liquor to the crystallization tank to ensure that the mother liquor at the outlet of the crystallization pump 5 can enter the heat exchanger for heat exchange.

[0045] The high-temperature ammonia-steaming wastewater and the mother liquor at the outlet of the crystallization pump 5 conduct heat exchange in the ammonia-water mother liquor heat exchanger 11, and the temperature of the mother liquor gradually rises. As the heat exchange process progresses, the temperature of the mother liquor at the outlet of the crystallization pump 5 continuously increases to ensure that the temperature of the mother liquor reaches a level where it can effectively dissolve ammonium sulfate.

[0046] The high-temperature mother liquor at the outlet of the crystallization pump 5 is sprayed onto the bottom of the saturator through the annular spraying pipe. The annular spraying pipe is made of a 316L stainless steel pipe with a Φ65mm diameter, and its diameter is smaller than the diameter of the bottom of the saturator. There are 16 holes in two rows, upper and lower, with a Φ15mm diameter on the annular spraying pipe, and nozzles are welded on the holes. The high-temperature mother liquor is evenly sprayed on the bottom of the saturator through the nozzles to flush the accumulated ammonium sulfate.

[0047] Utilizing the principle that the solubility of ammonium sulfate increases with the increase in the temperature of the mother liquor, the high-temperature mother liquor continuously flushes the ammonium sulfate at the bottom of the saturator, causing it to gradually dissolve. Through the continuous spraying of the annular spraying pipe, the accumulated ammonium sulfate is completely dissolved, restoring the unobstructed state of the bottom of the saturator.

[0048] This flushing operation can be carried out intermittently, once per shift, for no less than 30 minutes. Through intermittent flushing, it is ensured that ammonium sulfate will not accumulate again at the bottom of the saturator, guaranteeing the normal operation of the saturator.

[0049] When the temperature is relatively low in winter, the temperature of the saturator mother liquor may drop below 45°C, affecting the dissolution effect of ammonium sulfate. At this time, the valve from the crystallization pump 5 to the crystallization tank can be opened halfway, and all the valves of the heat exchanger can be fully opened and run continuously. Through continuous heat exchange, ensure that the mother liquor temperature is maintained above 55°C to stabilize the yield of ammonium sulfate produced by the saturator method.

[0050] During the flushing process, the direct gas valve of the saturator is kept at an opening degree of 30%-50% to prevent the accumulation of ammonium sulfate and ensure the normal transmission of gas. After the flushing is completed, slowly close the direct gas valve of the saturator and monitor the resistance of the saturator to ensure that the resistance drops below 2000 Pa and resume normal production.

[0051] After the flushing operation is completed, check the temperature change at the bottom of the saturator. The temperature at the bottom of the saturator rises from 15°C to 60°C, and the overall temperature of the saturator mother liquor rises to 50°C to ensure the complete dissolution of ammonium sulfate, the resistance of the saturator drops below 2000 Pa, and resume normal production.

[0052] Further, gas enters the saturator from the gas inlet 9, and the mother liquor is pumped out from the bottom of the saturator by the mother liquor circulation pump 6 and sprayed through the annular spraying device 4. The mother liquor circulates in the saturator, and the mother liquor circulation pump 6 plays a key role in the circulation power; the secondary spraying mother liquor pump 1 transports the mother liquor to the upper part of the saturator for secondary spraying to ensure full contact between the gas and the mother liquor. The gas rises in the saturator and fully contacts the mother liquor sprayed from the annular spraying device 4 and the saturator spraying tank 7. During this process, ammonia in the gas is absorbed by the mother liquor to form ammonium sulfate crystals.

[0053] After the ammonium sulfate crystals are formed in the saturator, they are pumped out from the bottom of the saturator by the crystallization pump 5, and the crystals are transported to the subsequent treatment process. The mother liquor is controlled by the overflow pipe 10 and the full flow tank 2 to ensure the stable liquid level of the mother liquor in the saturator. The gas after contacting the mother liquor and absorbing ammonia is discharged from the gas outlet 8 of the saturator.

[0054] The inlet valve 12 of the mother liquor to the heat exchanger controls the flow rate of the mother liquor entering the ammonia-mother liquor heat exchanger 11. In the heat exchanger, the mother liquor exchanges heat with the surplus ammonia water to adjust the temperature of the mother liquor. The inlet valve 14 of the surplus ammonia water to the heat exchanger and the outlet valve 15 of the surplus ammonia water heat exchanger control the flow rate of the surplus ammonia water entering and leaving the heat exchanger to ensure the normal progress of the heat exchange process. The valve 13 of the mother liquor to the crystallization tank controls the flow rate of the mother liquor flowing to the crystallization tank to ensure the smooth progress of the crystallization process. The vent pipe 3 is used to vent the liquid or gas in the saturator during equipment maintenance or other needs to ensure the safety of equipment operation.

[0055] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A self-cleaning spray saturator, characterized in that, Including: Annular spray pipe, annular spray pipe support, ammonia-mother liquor heat exchanger, cleaning interface; Annular spray pipe, which is made of 316L stainless steel pipe with a diameter of Φ65mm, and its diameter is smaller than the bottom diameter of the saturator. There are 16 spray holes in two upper and lower rows with a diameter of Φ15mm on the annular spray pipe, and nozzles are welded on the holes; Annular spray pipe support, which is welded at 30 - 40mm from the bottom of the saturator and is used to fix the annular spray pipe; Ammonia mother liquor heat exchanger, the heat exchanger is made of 316L stainless steel, and the heat exchange area is 200m 3 , which is used to exchange heat between the high-temperature ammonia-distilled wastewater under the ammonia distillation tower and the mother liquor at the outlet of the crystallization pump; Cleaning interface, which is connected to the ammonia-mother liquor heat exchanger through a 316L stainless steel pipe with DN65 and is used to introduce high-temperature mother liquor into the bottom of the saturator for flushing.

2. The self-cleaning spray saturator according to claim 1, characterized in that, The annular spray pipe is connected into two semi-circular rings through flanges. The diameter of the annular spray pipe is 2000mm, and the nozzles on the annular spray pipe are evenly distributed to ensure that the high-temperature mother liquor can be evenly sprayed on the bottom of the saturator.

3. The self-cleaning spray saturator according to claim 1, wherein, The ammonia-mother liquor heat exchanger is connected to the outlet pipe of the crystallization pump through a three-way pipe and a valve, and is used to exchange heat between high-temperature ammonia-removing wastewater and the mother liquor at the outlet of the crystallization pump to increase the temperature of the mother liquor.

4. An operating method of a self-cleaning spray saturator, characterized in that, Including the following steps: S1. Open the inlet valve and outlet valve of the ammonia-removing wastewater to allow 90°C high-temperature ammonia-removing wastewater to enter the ammonia-mother liquor heat exchanger; S2. Open the inlet valve for the mother liquor to enter the heat exchanger and close the valve for the mother liquor to the crystallization tank to allow the mother liquor at the outlet of the crystallization pump to exchange heat with the high-temperature ammonia-removing wastewater; S3. The temperature of the mother liquor at the outlet of the crystallization pump continuously rises, and the high-temperature mother liquor is continuously sprayed through the annular spray pipe to flush the ammonium sulfate accumulated at the bottom of the saturator; S4. Utilize the principle that the solubility of ammonium sulfate increases with the increase in the temperature of the mother liquor to dissolve all the accumulated ammonium sulfate and resume the normal production of the saturator.

5. The operating method of a self-cleaning spray saturator according to claim 4, characterized in that, In S3, use the intelligent nozzle flow regulating device to adjust the nozzle flow and angle in real time according to the information feedback by the ammonium sulfate accumulation detection system at the bottom of the saturator, and periodically flush the bottom of the saturator. Each cycle is not less than 30 minutes to ensure that there is no ammonium sulfate accumulation at the bottom of the saturator.

6. The operating method of a self-cleaning spray saturator according to claim 4, characterized in that, Based on the data feedback by the heat exchange efficiency monitoring sensor, when the heat exchange efficiency is lower than the set threshold, automatically adjust the flow rate and velocity of the ammonia-removing wastewater and the mother liquor to maintain the efficient operation of the heat exchange.

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