Method for cleaning gas-phase balance pipe of ammonium sulfate crystallizer

Abstract

The embodiment of the invention provides an ammonium sulfate crystallizer gas phase balance pipe cleaning method which comprises the following steps: injecting water into an emptied ammonium sulfate crystallizer, and heating to a preset temperature; the ammonium sulfate crystallizer is vacuumized through vacuum extraction equipment, so that the interior of the ammonium sulfate crystallizer reaches a preset vacuum degree, and the water is boiled; under the suction action of the vacuum extraction equipment, the gas-liquid multiphase flow impacts the inner side of the pipe wall of the gas-phase balance pipe of the ammonium sulfate crystallizer, so that ammonium sulfate crystals attached to the inner side of the pipe wall fall off, and the gas-liquid multiphase flow comprises water vapor and liquid water. According to the technical scheme, the ammonium sulfate crystallizer is vacuumized, on one hand, evaporation of heated liquid is facilitated, and on the other hand, high-temperature gas-liquid multiphase flow flies out at a high speed through negative pressure, so that ammonium sulfate crystals on the inner wall of the gas-phase balance pipe are scoured, the gas-phase balance pipe can be rapidly cleaned, and the service life of the gas-phase balance pipe is prolonged. The problems that manual flushing is low in efficiency and high in labor intensity are solved.

Description

Technical Field

[0001] The present invention relates to the field of environmental protection technologies, and particularly to a method for cleaning a gas-phase balance pipe of an ammonium sulfate crystallizer. Background Art

[0002] In the iron and steel manufacturing industry, sintering is one of the main production processes. A large amount of sulfur dioxide is generated during the production process. If it is directly discharged, it will seriously damage the atmospheric environment, so it needs to be removed.

[0003] There are many methods for removing sulfur dioxide. The wet desulfurization technology for sintering flue gas is the most mature. Among the wet desulfurization methods for sintering flue gas, the ammonia method is the most widely used. The desulfurization efficiency of the ammonia method can reach more than 98%. Ammonia water is used as the absorbent, and a mixed solution of (NH4)2SO3, (NH4)2SO4, and NH3HSO3 is used to circulate and absorb sulfur dioxide, so as to achieve the purpose of removing sulfur dioxide. Moreover, an ammonium sulfate solution with an appropriate concentration can enter the ammonium sulfate preparation system. After vacuum evaporation crystallization and centrifugal drying separation, high-quality ammonium sulfate by-products can be obtained. The whole process of this technology can achieve a win-win situation of "treating waste with waste" and obtain good environmental and economic benefits.

[0004] The evaporation crystallizer of the ammonium sulfate preparation system crystallizes at a low temperature under vacuum. After long-term operation, ammonium sulfate crystals will adhere to the inner wall of the top outlet of the crystallizer, that is, the gas-phase balance pipe, and gradually block the gas-phase balance pipe, resulting in poor performance of the ammonium sulfate preparation system and corresponding increase in steam consumption. Therefore, it is necessary to regularly clean the inside of the gas-phase balance pipe.

[0005] In the process of implementing the present invention, the inventor found that there are at least the following problems in the prior art:

[0006] The existing cleaning method is to open a manhole on the gas-phase balance pipe, and then connect industrial water and use a fire hose for manual flushing operation. However, this method is very difficult to clean the relatively hard ammonium sulfate crystals, and at the same time, it is very difficult to improve the speed by the manual operation method itself, resulting in a long cleaning time and low efficiency for the whole cleaning work. Therefore, how to improve the cleaning efficiency of the inner wall of the gas-phase balance pipe is a problem to be solved. Summary of the Invention

[0007] An embodiment of the present invention provides a method for cleaning a gas-phase balance pipe of an ammonium sulfate crystallizer to improve the cleaning efficiency.

[0008] To achieve the above object, an embodiment of the present invention provides a method for cleaning the gas-phase equilibrium pipe of an ammonium sulfate crystallizer, including: injecting a cleaning liquid into the emptied ammonium sulfate crystallizer and heating the cleaning liquid to a preset temperature; evacuating the ammonium sulfate crystallizer by a vacuum extraction device to make the inside of the ammonium sulfate crystallizer reach a preset vacuum degree so that the water in the cleaning liquid boils; through the suction action of the vacuum extraction device, making the gas-liquid multiphase flow impact the inner wall of the gas-phase equilibrium pipe of the ammonium sulfate crystallizer so that the ammonium sulfate crystals attached to the inner wall of the pipe fall off, wherein the gas-liquid multiphase flow includes water vapor and liquid water.

[0009] Further, the cleaning liquid is water and / or a low-concentration ammonium sulfate solution.

[0010] Further, the vacuum extraction device is a steam condenser; the method for cleaning the gas-phase equilibrium pipe of the ammonium sulfate crystallizer further includes: cooling the gas-liquid multiphase flow by the steam condenser to form a condensed liquid; connecting the storage container of the condensed liquid to the liquid inlet pipe of the ammonium sulfate crystallizer.

[0011] Further, during the process of injecting the cleaning liquid, the liquid level is controlled at two-thirds to three-fourths of the volume of the ammonium sulfate crystallizer.

[0012] Further, the preset temperature is 75°C to 85°C.

[0013] Further, the preset vacuum degree is -85 kPa to -70 kPa.

[0014] Further, the time for the gas-liquid multiphase flow to impact the gas-phase equilibrium pipe of the ammonium sulfate crystallizer is controlled at 5 min to 20 min.

[0015] Further, the method for cleaning the gas-phase equilibrium pipe of the ammonium sulfate crystallizer further includes: after completing the cleaning of the gas-phase equilibrium pipe of the ammonium sulfate crystallizer, knocking on the gas-phase equilibrium pipe of the ammonium sulfate crystallizer, and judging whether ammonium sulfate crystals are still attached to the inner wall of the gas-phase equilibrium pipe of the ammonium sulfate crystallizer through the knocking echo. If not, repeat the cleaning.

[0016] The above technical solution has the following beneficial effects:

[0017] In this technical solution, evacuating the ammonium sulfate crystallizer is beneficial to the boiling of the heated liquid on the one hand, and on the other hand, through negative pressure, the high-temperature gas-liquid multiphase flow flies out at high speed and is drawn into the gas-phase equilibrium pipe, thereby flushing the ammonium sulfate crystals on the inner wall of the gas-phase equilibrium pipe, and the gas-phase equilibrium pipe can be quickly cleaned, solving the problem of low efficiency in manual flushing.

[0018] In addition, this technical solution also has the following characteristics:

[0019] 1) After adopting this technical solution, there is no need to open manholes on the gas-phase equilibrium pipe, and the operation is simple. It can also be remotely controlled without on-site operation by staff, thus greatly reducing the labor intensity.

[0020] 2) This technical solution can also achieve the secondary utilization of water resources. After flushing, the ammonium sulfate crystals in the gas-phase equilibrium pipe are dissolved by high-temperature water to form an ammonium sulfate solution, which can be transported to the desulfurization tower for recycling. Through evaporation and concentration in the desulfurization tower, crystallization occurs again, achieving a win-win situation for environmental and economic benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] 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 use in the embodiments. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0022] Figure 1 is a flowchart of a method for cleaning the gas-phase equilibrium pipe of an ammonium sulfate crystallizer according to an embodiment of the present invention;

[0023] Figure 2 is a schematic diagram of the device used in a specific embodiment of an embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0024] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, rather than all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0025] As Figure 1 shown, an embodiment of the present invention provides a method for cleaning the gas-phase equilibrium pipe of an ammonium sulfate crystallizer, including:

[0026] S101. Inject a cleaning liquid into the emptied ammonium sulfate crystallizer and heat the cleaning liquid to a preset temperature;

[0027] S102. Use a vacuum extraction device to evacuate the ammonium sulfate crystallizer to make the inside of the ammonium sulfate crystallizer reach a preset vacuum degree, so that the water in the cleaning liquid boils;

[0028] S103. Through the suction effect of the vacuum extraction device, make the gas-liquid multiphase flow impact the inner wall of the gas-phase equilibrium pipe of the ammonium sulfate crystallizer, so that the ammonium sulfate crystals attached to the inner wall of the pipe fall off, where the gas-liquid multiphase flow includes water vapor and liquid water.

[0029] As described above, when cleaning the gas-phase equilibrium pipe of the ammonium sulfate crystallizer in the prior art, it is necessary to open manholes on the pipeline, and then connect industrial water and use a fire hose for manual flushing operations. In this operation mode, due to the low temperature of industrial water, the dissolution effect on the agglomerated ammonium sulfate crystals is very poor. At the same time, restricted by the working environment, the work efficiency is very low, and the cleaning operation takes a long time. To solve this problem, in the embodiment of the present invention, a vacuum extraction device is connected to the gas-phase equilibrium pipe, so that the gas-phase equilibrium pipe itself becomes a necessary passage when evacuating (preferably connecting the vacuum extraction device to the end of the gas-phase equilibrium pipe far from the ammonium sulfate crystallizer, so that all parts of the gas-phase equilibrium pipe can be flushed by the gas-liquid multiphase flow during operation without dead ends). During operation, instead of using the form of on-site manual operation, water is injected into the ammonium sulfate crystallizer and heated, and then negative pressure is formed in the container by evacuating, so that the boiling water generates a gas-liquid multiphase flow of gas and liquid. Under the continuous suction of the vacuum extraction device, the high-temperature gas-liquid multiphase flow impacts the inner wall of the gas-phase equilibrium pipe at high speed, causing the ammonium sulfate crystals to fall off and dissolve, thus quickly completing the cleaning of the gas-phase equilibrium pipe, greatly improving the work efficiency, reducing the labor intensity, and through actual measurement, the cleaning effect is better.

[0030] Further, the cleaning liquid can be water, or a low-concentration ammonium sulfate solution can be directly used. When heating and then evacuating, the water in the solution can also boil to achieve the cleaning purpose.

[0031] Further, the vacuum extraction device adopts a steam condenser. At this time, the method for cleaning the gas-phase equilibrium pipe of the ammonium sulfate crystallizer further includes: cooling the gas-liquid multiphase flow through the steam condenser to form a condensed liquid; connecting the storage container of the condensed liquid to the liquid inlet pipe of the ammonium sulfate crystallizer. In this way, during subsequent cleaning operations, the condensed liquid in the storage container can be added to the ammonium sulfate crystallizer, realizing the secondary utilization of water resources and enabling the recovery of ammonium sulfate, with better economic and social benefits.

[0032] Further, in the above steps, according to actual measurement, better implementation effects can be obtained by controlling with the following parameters:

[0033] In step S101, when injecting the cleaning liquid, the liquid level should be controlled at two-thirds to three-fourths of the volume of the ammonium sulfate crystallizer; the preset heating temperature is 75°C to 85°C.

[0034] In step S102, the vacuum degree should be controlled between -85 kPa and -70 kPa.

[0035] In step S103, the time for the gas-liquid multiphase flow to impact the gas-phase equilibrium pipe of the ammonium sulfate crystallizer (or the pumping and flushing time) is controlled at 5 min to 20 min, for example, 10 minutes, to achieve a more reasonable balance.

[0036] It should be noted that 75°C to 85°C is the most suitable temperature for the cleaning method of the gas-phase equilibrium pipe of the ammonium sulfate crystallizer in this application. If the temperature is too high, it may damage the equipment, and if the temperature is too low, due to factors such as the reduced solubility of ammonium sulfate crystals, a good cleaning effect cannot be achieved.

[0037] Furthermore, the cleaning method of the gas-phase equilibrium pipe of the ammonium sulfate crystallizer further includes:

[0038] After completing the cleaning of the gas-phase equilibrium pipe of the ammonium sulfate crystallizer, tap the gas-phase equilibrium pipe of the ammonium sulfate crystallizer, and determine whether ammonium sulfate crystals are still attached to the inner wall of the gas-phase equilibrium pipe of the ammonium sulfate crystallizer through the tapping echo. If not, repeat the cleaning.

[0039] The following uses a specific embodiment to illustrate the above method in detail. The device used in this specific embodiment is as Figure 2 shown. It uses a steam condenser 3 to evacuate the air, and its working process is as follows:

[0040] Step A: Drain the original ammonium sulfate solution in the ammonium sulfate crystallizer 1, and then inject the water (or low-concentration ammonium sulfate solution) in the liquid inlet tank 4 into the ammonium sulfate crystallizer 1 through the liquid inlet pump and the crystallizer liquid inlet pipeline 7, or the condensed water (or low-concentration ammonium sulfate solution) in the condensed water collection tank 2 through the condensed water pipeline 5;

[0041] Step B: After the water injection is completed, heat the water in the ammonium sulfate crystallizer 1. When the liquid temperature reaches 75 - 85°C, the heating is completed;

[0042] Step C: After the heating is completed, turn on the steam condenser 3 and start evacuating the air from the ammonium sulfate crystallizer 1 until the vacuum degree in the ammonium sulfate crystallizer 1 is -85 kPa to -70 kPa. At this time, the hot water can boil through the negative pressure state, and the pumping and flushing operation starts;

[0043] Step D: The boiling water vapor mixed with liquid water droplets and the like forms a gas-liquid multiphase flow, and through the negative pressure effect, it flies into the gas-phase equilibrium pipe 6, scouring the agglomerated ammonium sulfate crystals in the gas-phase equilibrium pipe 6, so that the ammonium sulfate crystals fall off and are dissolved by water or low-concentration ammonium sulfate solution;

[0044] Step E: After passing through the steam condenser 3, the condensed water (or low-concentration ammonium sulfate solution) is collected in the condensed water collection tank 2;

[0045] Step F: The pumping and flushing operation lasts for 10 minutes. After the pumping and flushing operation is completed, continue to use the large circulation pump to flush each solution pipeline of the ammonium sulfate system;

[0046] Step G: Drain the water in the ammonium sulfate system, and the cleaning of the gas-phase equilibrium pipe 6 is completed. The ammonium sulfate system is on standby;

[0047] Step H: Determine whether the gas-phase equilibrium tube 6 is cleaned by physical tapping. Since the gas-phase equilibrium tube 6 is a stainless steel tube, by hitting the equilibrium tube with metal, if the echo is clear, it indicates that it has been cleaned. If the echo is dull, it means there is still caking inside the tube wall. At this time, the above-mentioned steps can be repeated for further cleaning.

[0048] Figure 2 In it, the solid line represents the liquid passage, and the dotted line represents the passage of steam or gas-liquid multiphase flow.

[0049] After actual measurement, for the ammonium sulfate preparation system of this specific embodiment, after adopting the method of this application, the cleaning time is 1 - 2 hours. In contrast, when conventional manual cleaning was used before, the average cleaning time was about 24 hours. Thus, it can be seen that the method of this application has greatly improved the working efficiency.

[0050] In the above detailed description, various features are combined in a single embodiment to simplify the present disclosure. This method of disclosure should not be interpreted as reflecting the intention that the embodiments of the claimed subject matter require more features than those clearly stated in each claim. On the contrary, as reflected in the appended claims, the present invention is in a state with fewer features than all the features of the disclosed single embodiment. Therefore, the appended claims are hereby clearly incorporated into the detailed description, where each claim stands alone as a separate preferred embodiment of the present invention.

[0051] In order to enable any person skilled in the art to implement or use the present invention, the disclosed embodiments have been described above. For those skilled in the art, various modification methods of these embodiments are obvious, and the general principles defined herein can also be applied to other embodiments without departing from the spirit and protection scope of the present disclosure. Therefore, the present disclosure is not limited to the embodiments given herein, but is consistent with the broadest scope of the principles and novel features disclosed in this application.

[0052] The specific embodiments described above further elaborate on the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above is only the specific embodiment of the present invention and is not used to limit the protection scope of the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A cleaning method for the gas-phase equilibrium pipe of an ammonium sulfate crystallizer, characterized in that Including: Inject a cleaning liquid into the emptied ammonium sulfate crystallizer and heat the cleaning liquid to a preset temperature; Use a vacuum extraction device to evacuate the ammonium sulfate crystallizer to make the inside of the ammonium sulfate crystallizer reach a preset vacuum degree, so that the water in the cleaning liquid boils; Through the suction action of the vacuum extraction device, make the gas-liquid multiphase flow impact the inner wall of the gas-phase equilibrium pipe of the ammonium sulfate crystallizer, so that the ammonium sulfate crystals attached to the inner wall of the pipe fall off, wherein the gas-liquid multiphase flow includes water vapor and liquid water.

2. The method for cleaning the gas-phase equilibrium pipe of the ammonium sulfate crystallizer according to claim 1, characterized in that, The cleaning liquid is water and / or ammonium sulfate solution.

3. The method for cleaning the gas phase equilibrium pipe of the ammonium sulfate crystallizer according to claim 2, characterized in that, The vacuum extraction device is a steam condenser; The method for cleaning the gas-phase equilibrium pipe of the ammonium sulfate crystallizer further includes: Cool the gas-liquid multiphase flow through a steam condenser to form a condensed liquid; Connect the storage container of the condensed liquid to the liquid inlet pipe of the ammonium sulfate crystallizer.

4. The cleaning method of the gas phase equilibrium pipe of the ammonium sulfate crystallizer according to claim 2, characterized in that, During the process of injecting the cleaning liquid, the liquid level is controlled at two-thirds to three-fourths of the volume of the ammonium sulfate crystallizer.

5. The method for cleaning the gas phase equilibrium pipe of the ammonium sulfate crystallizer according to claim 2, characterized in that, The preset temperature is 75°C to 85°C.

6. The method for cleaning the gas-phase equilibrium pipe of the ammonium sulfate crystallizer according to claim 2, characterized in that, The preset vacuum degree is -85 kPa to -70 kPa.

7. The method for cleaning the gas-phase equilibrium pipe of the ammonium sulfate crystallizer according to claim 2, characterized in that, Control the time for the gas-liquid multiphase flow to impact the gas-phase equilibrium pipe of the ammonium sulfate crystallizer within 5 min to 20 min.

8. The cleaning method of the gas phase equilibrium pipe of the ammonium sulfate crystallizer according to claim 2, characterized in that, Also including: After completing the cleaning of the gas-phase equilibrium pipe of the ammonium sulfate crystallizer, tap the gas-phase equilibrium pipe of the ammonium sulfate crystallizer, and determine whether ammonium sulfate crystals are still attached to the inner wall of the gas-phase equilibrium pipe of the ammonium sulfate crystallizer through the tapping echo. If not, repeat the cleaning.

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