Double-tower coupled coal chemical industry wastewater deacidification and deamination process

Abstract

The invention belongs to the technical field of wastewater treatment and utilization, and relates to a double-tower coupled coal chemical industry wastewater deacidification and deamination process, to-be-treated wastewater is divided into a cold part and a hot part to enter a deacidification tower from the upper part and the middle upper part of the deacidification tower respectively, deacidification tower kettle liquid without most acidic gas is pumped to the upper part of a deamination tower, and the deamination tower kettle liquid is pumped to the lower part of the deamination tower; after ammonia-containing water vapor is stripped from the top of the deamination tower, one part of the ammonia-containing water vapor enters the multi-stage segregation device, and the other part of the ammonia-containing water vapor enters the tower kettle of the deacidification tower to be used as a heat source of the deacidification tower; the segregation device is also connected with an ammonia water vapor compressor, and part of ammonia-containing water vapor is boosted to be slightly higher than the pressure of the tower kettle of the deacidification tower and then enters the deacidification tower. According to the process disclosed by the invention, deacidification and deamination are carried out in two towers, meanwhile, the deacidification tower is not provided with a reboiler, and a part of ammonia water vapor separated from the deamination tower is selected to enter the deacidification tower, so that a heat source is provided on one hand, and the reaction is more thorough through the disturbance action of gas on the other hand; and heat loss caused by the fact that waste gas directly flows out from the top of the deacidification tower is reduced or prevented.

Description

Technical Field

[0001] The invention belongs to the technical field of wastewater treatment and utilization, and relates to a method for treating wastewater containing acidic gas and ammonia, and specifically to a double-tower coupled coal chemical wastewater deacidification and deammoniation process. Background Art

[0002] In the process of coal conversion, a large amount of wastewater containing acidic gases (including carbon dioxide, hydrogen sulfide, etc.) and ammonia will be produced. Since acidic gases and ammonia will affect subsequent biochemical treatment, it is necessary to separate and recycle them. Steam stripping is the main common technical method for removing acidic gases and ammonia in the current industrial process. Generally, there are single-tower stripping with side lines and double-tower stripping processes, which are widely used in enterprises. These processes have their own advantages and disadvantages. For example, the Chinese patent CN1884150A applied by the inventor in 2006 discloses a method and device for treating coal gasification wastewater by single-tower pressurized stripping. The single-tower stripping process with side lines is adopted. The process often has problems such as side line liquid and unstable control, and is limited by height, and the difficulty of large-scale device is relatively large.

[0003] The double-tower stripping process does not have the above-mentioned disadvantages, has a relatively stable operation, and has good amplification performance, but the steam consumption is relatively high. In order to reduce the energy consumption of the double-tower stripping process, the inventor introduced the use of double-effect technology in the double-tower stripping process and applied for a patent, namely Chinese patent CN102320671A, which discloses a method for treating acid- and ammonia-containing wastewater. The method uses ammonia water vapor extracted from the deamination tower instead of steam as the heating medium for the deacidification tower reboiler, thereby reducing the consumption of steam per ton by 50 to 70 kilograms. However, the setting of this technology makes deacidification only possible at relatively low pressures, limiting its application scenarios. For example, when applied to wastewater with a high ammonia content or organic matter content, wastewater containing other alkaline components, and wastewater with a high sulfide content, its deacidification efficiency is low, resulting in the effluent sulfide often exceeding the standard.

[0004] With the advancement of coal chemical technology and the increasing scale of production, the wastewater pollution load is getting higher and higher, and the water volume of a single project is also increasing. The increase in wastewater pollution load means the increase in the concentration of organic matter in the wastewater. According to relevant data statistics, the higher the concentration of organic matter, the greater the impact on the deacidification and deammonification stripping efficiency, so the effluent is often unqualified or requires greater energy consumption; if the amount of wastewater in a single project is large, it is hoped that the scale of a single series of equipment can be expanded in time to reduce the number of sets and reduce management and operating costs. Based on the current situation, it is urgent to develop a deacidification and deammonification process that is energy-saving, stable, and has good scalability. Summary of the invention

[0005] The purpose of the present invention is to solve the above-mentioned problems existing in the prior art, and proposes a double-tower coupled coal chemical wastewater deacidification and deammoniation process, which can effectively remove acid gases and ammonia, reduce steam consumption, achieve energy-saving effects, and the device and process are stable and easy to scale up.

[0006] The technical solution of the present invention is:

[0007] After analysis, it is found that organic matter accumulates at the gas-liquid interface to form a relatively rigid film layer, thereby inhibiting the mass transfer of ammonia between the gas and liquid phases. As the organic matter content of current wastewater is getting higher and higher, this inhibition has significantly affected the stripping effect. Since the gas-liquid ratio in the deacidification process is smaller, the deacidification efficiency is more affected by organic matter. In order to solve this problem, how to increase the disturbance between the gas and liquid phases to promote the timely transfer of molecular weak electrolytes into the gas phase is the key to improving the stripping effect. In order to achieve this goal, the present invention first selects a tower plate type with a liquid phase as a dispersed phase, so that the liquid phase is broken into small droplets during the stripping process to promote interphase disturbance; in addition, the residence time of the liquid phase on the tower plate is appropriately increased to break the interphase diffusion bottleneck.

[0008] In addition, considering that the temperature at the top of the deacidification tower has an upper limit, measures need to be taken to ensure that when the heat content of the stripping gas is certain, the volume of the rising gas in the deacidification tower can be increased. To this end, based on the previous double-tower technology, the present invention proposes a strategy of directly introducing part of the top gas of the deacidification tower into the deacidification tower kettle as a heat source. This strategy not only saves the reboiler of the deacidification tower, but also ensures that when the heat is certain, the stripping gas has a larger volume, which can have a greater disturbing effect on the liquid phase during the stripping process. The scheme also compresses the first-level ammonia vapor and refluxes it, further increasing the volume of the rising gas in the deacidification tower and increasing the disturbing effect.

[0009] Based on this, the present invention provides a double-tower coupled coal chemical wastewater deacidification and deammoniation process, wherein the cold and hot parts of the wastewater to be treated enter the tower from the upper part and the middle-upper part of the deacidification tower respectively, and the deacidification tower bottom liquid from which most of the acidic gases are removed is pumped to the upper part of the deammonification tower, and the deacidification tower and the deammonification tower both use a jet-state tower tray with a gas phase as a continuous phase and a liquid phase as a dispersed phase; after the ammonia-containing water vapor is stripped from the top of the deammonification tower, a part of it enters a multi-stage condensation device, and the other part enters the deacidification tower bottom, which is used as a heat source for the deacidification tower;

[0010] The multi-stage condensation device comprises a first-stage condensation cooler and a first-stage liquid separation tank, wherein the first-stage liquid separation tank is connected to an ammonia vapor compressor, and the ammonia vapor compressor is connected to the deacidification tower kettle;

[0011] When the organic matter content in the wastewater is particularly high or the ratio of the acid gas content to the ammonia content in the wastewater is greater than 2, start the ammonia vapor compressor to pressurize the treated part of the ammonia vapor to a pressure slightly higher than the deacidification tower kettle pressure before entering the lower part of the deacidification tower.

[0012] Further, the multi-stage condensation device includes a primary condensation device, a secondary condensation device and a tertiary condensation device;

[0013] The first-stage fractional condensation device includes a first-stage condensation cooler and a first-stage liquid separation tank connected in sequence; the second-stage fractional condensation device includes a first-stage condensation cooler, a first-stage liquid separation tank, a second-stage condensation cooler and a second-stage liquid separation tank connected in sequence; the third-stage fractional condensation device includes a first-stage condensation cooler, a first-stage liquid separation tank, a second-stage condensation cooler, a second-stage liquid separation tank, a third-stage condensation cooler and a third-stage liquid separation tank connected in sequence.

[0014] Furthermore, the upper gas phase outlet of the first-stage liquid separator is connected to an ammonia vapor compressor, and the ammonia vapor compressor is connected to the gas phase space of the deacidification tower kettle;

[0015] After being treated by the primary condensation device, part of the ammonia-containing water vapor is pressurized to a pressure slightly higher than the deacidification tower bottom pressure and then enters the lower part of the deacidification tower; the deamination tower bottom liquid is sent to the subsequent treatment device after heat exchange cooling through the second centrifugal pump.

[0016] Furthermore, the lower liquid phase outlets of each liquid separation tank in the multi-stage liquid separation device are connected to an ammonia condensation cooler and an ammonia condensate tank. After the ammonia-containing water vapor is stripped out from the top of the deamination tower, a portion of it enters the multi-stage condensation device, and after multiple partial condensations, ammonia water vapor or crude ammonia gas of the required concentration is obtained, which is sent to the downstream device for processing or direct use through a third centrifugal pump.

[0017] Furthermore, the bottom liquid phase of the deacidification tower is connected to a first centrifugal pump, and the bottom liquid phase of the deammoniation tower is connected to a reboiler and a second centrifugal pump.

[0018] Furthermore, the top of the deacidification tower is connected to an acid gas condenser and an acid separation tank in sequence, and the acid gas enters the acid gas condenser from the top of the tower for condensation, and then enters the subsequent treatment device after separation in the acid separation tank.

[0019] Furthermore, the number of theoretical plates of the deacidification tower is 8 to 20, and the top temperature of the deacidification tower is 40 to 120°C; the number of theoretical plates of the deamination tower is 15 to 35, the top pressure of the deamination tower is 0.23 to 0.55 MPa, the top temperature is 120 to 150°C, the bottom pressure is 0.26 to 0.58 MPa, and the bottom temperature is 128 to 165°C.

[0020] Furthermore, the upper part and the upper middle part of the deacidification tower are connected to the cold and hot feed pipelines respectively, and the liquid phase outlet of the tower bottom is connected to the upper part of the deamination tower through the first centrifugal pump and the pipeline.

[0021] Furthermore, the wastewater to be treated is coal chemical wastewater containing acidic gas and ammonia.

[0022] Beneficial effects of the present invention:

[0023] (1) The process flow of the present invention separates deacidification and deamination into two towers. At the same time, the deacidification tower is not equipped with a reboiler. Instead, a portion of ammonia vapor is separated from the deamination tower and enters the deacidification tower. On the one hand, it provides a heat source. On the other hand, it can increase the volume of the rising gas while ensuring that the total heat of the rising gas in the deacidification tower is constant and the top temperature of the deacidification tower does not exceed the standard. In addition, in the scheme of the present invention, the first-level ammonia vapor is compressed and refluxed, further increasing the volume of the rising gas in the deacidification tower. In the case where the tower tray is a jet-type tower tray, the increase in the volume of the rising gas can enhance the disturbance at the gas-liquid phase, so that the dissociation reaction of ammonia and acidic gas in the liquid phase is rapid, and the barrier effect of organic matter at the gas-liquid phase is broken, thereby significantly improving the efficiency of deacidification. At the same time, this scheme has the advantages of stability and reliability of the traditional double-tower stripping process, and the steam consumption is about 20% lower than that of the traditional double-tower stripping process.

[0024] (2) Compared with the single-tower process with side-line extraction, the steam consumption of the process flow of the present invention is comparable to that of the single-tower process with side-line extraction, and both are relatively energy-efficient, but the stability is better than that of the single-tower process with side-line extraction, and there is no problem of side-line liquid carryover. When the device is scaled up, the process of the present invention is used to separate the deacidification and deamination, which can avoid the problem of tower height limitation and improve the safety and stability of the device. Therefore, the process can be widely used in large-scale steam stripping treatment devices for coal chemical wastewater.

[0025] (3) Coal chemical wastewater is prone to fouling and blockage in the deamination section during the deacidification and deamination process. If the process of the present invention is adopted, only the deamination tower needs to be opened when the plant is shut down for cleaning, which reduces the maintenance workload and avoids the risk of spontaneous combustion of the deacidification tower after contact with air. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 A schematic diagram of the structure principle of the double-tower coupled coal chemical wastewater deacidification and deammoniation process provided by the present invention;

[0027] In the figure, 1, deacidification tower; 2, deammonification tower; 3, primary condenser cooler; 4, primary separator tank; 5, secondary condenser cooler; 6, secondary separator tank; 7, tertiary condenser cooler; 8, tertiary separator tank; 9, ammonia condensate tank; 10, first centrifugal pump; 11, second centrifugal pump; 12, third centrifugal pump; 13, acid gas condenser; 14, acid separator tank; 15, ammonia vapor compressor. DETAILED DESCRIPTION

[0028] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions 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. 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.

[0029] In order to further understand the present invention, the present invention will be further described in conjunction with the accompanying drawings and embodiments.

[0030] like Figure 1 As shown, the present invention provides a dual-tower coupled coal chemical wastewater deacidification and deammoniation process, which uses a deacidification tower 1 and a deammonification tower 2 coupling device, wherein the number of theoretical plates of the deacidification tower 1 is 8 to 20, and the number of theoretical plates of the deammonification tower 2 is 15 to 35. The process steps are as follows:

[0031] The acid and ammonia wastewater to be treated is divided into cold and hot parts, which enter the deacidification tower 1 from the upper part and the middle upper part through the cold and hot feed pipelines, respectively, and the top temperature of the deacidification tower 1 is adjusted and controlled to be 40-120° C. The acid gas comes out from the top of the tower, passes through the acid gas condenser 13 and the acid liquid separation tank 14 connected to the top of the deacidification tower 1 in sequence, and enters the subsequent treatment device after condensation and liquid separation.

[0032] The kettle liquid of the deacidification tower 1 from which most of the acidic gas has been removed is pumped to the first tray on the top of the deamination tower 2 by the first centrifugal pump 10; the top pressure of the deamination tower 2 is 0.23-0.55 MPa, the top temperature is 120-150°C, the bottom pressure is 0.26-0.58 MPa, and the bottom temperature is 128-165°C. At this time, the top pressure of the deacidification tower 1 is 0.2-0.5 MPa, the top temperature is 40-120°C, the bottom pressure is 0.22-0.52 MPa, and the bottom temperature is 120-149°C.

[0033] After the ammonia-containing water vapor is stripped from the top of the deamination tower 2, a part of it enters a multi-stage condensation device (composed of a first-stage condensation cooler 3, a first-stage liquid separator 4, a second-stage condensation cooler 5, a second-stage liquid separator 6, a third-stage condensation cooler 7, and a third-stage liquid separator 8 connected in series in part or in whole), and after multiple partial condensations in the ammonia condensation cooler and the ammonia condensate tank 9, ammonia water vapor or crude ammonia gas of the required concentration is obtained, which is sent to the downstream device for processing or directly used through the third centrifugal pump 12. Another part of the ammonia water vapor extracted from the top of the deamination tower 2 enters the kettle of the deacidification tower 1 and is used as a heat source for the deacidification tower 1, and the deacidification tower 1 is not provided with a reboiler.

[0034] For ammonia-containing water systems with extremely high organic matter content or a ratio of acid gas content to ammonia content greater than 2, part of the ammonia vapor after the first-stage condensation (i.e., passing through the first-stage condenser cooler 3 and the first-stage liquid separator 4) enters the ammonia vapor compressor 15 to increase the pressure to 0.24-0.54MPa (this pressure is slightly higher than the deacidification tower kettle pressure of 0.22-0.52Mpa), and then enters the lower part of the deacidification tower 1; the deacidification tower 2 kettle liquid is partially extracted and sent to the subsequent treatment device after heat exchange cooling. The deacidification tower 2 is equipped with a reboiler and heated by an external heat utility.

[0035] Example 1

[0036] A semi-coke and tar processing enterprise in Shaanxi needs to treat 120 tons of acidic and ammoniacal wastewater per hour, and the wastewater contains about 12000 mg / L of hydrogen sulfide and about 14000 mg / L of ammonia. The double-tower coupling device of the present invention is used for deacidification and deammoniation treatment, wherein the theoretical plates of the deacidification tower 1 and the deammonification tower 2 are 20 and 35 respectively.

[0037] The deacidification and deamination process of this embodiment is as follows: the wastewater is divided into cold and hot parts and enters the deacidification tower 1 from the upper part and the middle upper part respectively, and the top pressure of the deacidification tower 1 is adjusted to be 0.5MPa and the top temperature is 120°C; the bottom pressure of the deamination tower 2 is 0.52Mpa and the bottom temperature is 149°C. The acid gas comes out from the top of the tower, and after condensation and liquid separation, it enters the subsequent sulfur recovery device; the kettle liquid of the deacidification tower 1 with most of the acid gas removed is pumped to the first tray on the top of the deamination tower 2; the top pressure of the deamination tower 2 is 0.55Mpa, the top temperature is 120-150°C, the bottom pressure is 0.58Mpa, and the bottom temperature is 165°C. After the ammonia-containing water vapor is stripped from the top of the deamination tower 2, a part of it enters the three-stage condensation device, and after multiple partial condensations, the crude ammonia gas is obtained and sent to the denitration device for use; the deacidification tower 1 is not equipped with a reboiler, and another part of the ammonia water vapor enters the kettle of the deacidification tower 1 and is used as the heat source of the deacidification tower 1; the kettle liquid of the deamination tower 2 is sent to the subsequent extraction dephenolization device after heat exchange cooling. The deamination tower 2 is equipped with a reboiler and heated with 1.0MPa steam.

[0038] After the above treatment, the residual amount of hydrogen sulfide in the wastewater is less than 15mg / L, and the total ammonia content is less than 100mg / L, which meets the prescribed standards. The steam consumption for treating one ton of water is about 185 kg, which is 40-55 kg lower than that of similar devices.

[0039] Example 2

[0040] A coal-to-gas enterprise located in Inner Mongolia has newly built a stripping device using the double-tower coupled stripping process of the present invention, with a single device scale of 400 tons / hour. The original wastewater contains about 150 mg / L of hydrogen sulfide, about 16,000 mg / L of carbon dioxide, and about 14,000 mg / L of ammonia. The double-tower coupled device of the present invention is used for deacidification and deammoniation treatment, wherein the theoretical plates of the deacidification tower 1 and the deammonification tower 2 are 15 and 28, respectively.

[0041] The process steps are: the wastewater is divided into cold and hot parts and enters the deacidification tower 1 from the upper part and the middle upper part respectively, and the top pressure of the deacidification tower 1 is adjusted to be 0.2MPa, the top temperature is 60℃, and the bottom pressure of the deamination tower 2 is 0.22Mpa, and the bottom temperature is 120℃. The acid gas comes out from the top of the tower and enters the subsequent treatment device; the kettle liquid of the deacidification tower 1 with most of the acid gas removed is pumped to the first tray on the top of the deamination tower 2; the top pressure of the deamination tower 2 is 0.23Mpa, the top temperature is 120℃, the bottom pressure is 0.26Mpa, and the bottom temperature is 128℃. After the ammonia-containing water vapor is stripped from the top of the deamination tower 2, a part of it enters the two-stage condensation device, and after two partial condensations, ammonia water vapor with a concentration of 90% is obtained, which is sent to the flue gas desulfurization device for use; the deacidification tower 1 is not equipped with a reboiler, and another part of the ammonia water vapor enters the kettle of the deacidification tower 1 and is used as the heat source of the deacidification tower 1; the kettle liquid of the deamination tower 2 is sent to the subsequent extraction and desulfurization device after heat exchange cooling. The deamination tower 2 is equipped with a reboiler and heated with 0.5MPa water vapor.

[0042] After the above treatment, the residual hydrogen sulfide content of the wastewater is less than 10 mg / L, the carbon dioxide content is less than 100 mg / L, and the total ammonia content is less than 150 mg / L, which meets the prescribed standards.

[0043] The enterprise produces 1,520 tons of acidic and ammoniacal wastewater per hour. In addition to the 400 tons / hour device of the present invention, there are 4 treatment devices built earlier, of which 2 sets of 280 tons / hour devices adopt the traditional double-tower process, and the other 2 sets of 280 tons / hour devices adopt the energy-saving double-tower stripping process proposed by patent CN102320671A. The actual operation of the process device using the present invention is more efficient, stable and reliable. The content of hydrogen sulfide and acid gas after treatment is only 30-40% of the original 4 sets of devices; in terms of energy consumption, the steam consumption of the present invention for treating a ton of water is about 188 kilograms, which is 60 kilograms lower than that of the device using the traditional double-tower process, and is equivalent to the energy consumption of the device using invention CN102320671A. At the same time, the device is currently the largest deacidification and deammoniation device built in the world, showing that the process has excellent scale-up stability.

[0044] Example 3

[0045] A semi-coke wastewater treatment enterprise located in Yulin needs to treat 500 tons of semi-coke wastewater containing acid and ammonia per hour, and the scale of a single unit is 250 tons / hour; the wastewater contains about 800 mg / L of hydrogen sulfide, about 3000 mg / L of carbon dioxide, and about 5000 mg / L of ammonia. The organic matter content of the wastewater is particularly high, and the COD exceeds 50000 mg / L. The traditional double-tower stripping process was originally adopted, but the steam consumption was high and the treatment effect was not ideal. The original device was transformed using the technology designed by the present invention, and the transformed device is a double-tower coupling device, in which the theoretical plates of the deacidification tower 1 and the deammonification tower 2 are 15 and 28 respectively.

[0046] The process steps after the transformation are: the wastewater is divided into cold and hot parts, which enter the deacidification tower 1 from the upper part and the middle upper part respectively, and the top pressure of the deacidification tower 1 is adjusted to 0.2MPa and the top temperature is 60℃; the bottom pressure of the deamination tower 2 is 0.22Mpa and the bottom temperature is 120℃. The acid gas comes out from the top of the tower and enters the subsequent treatment device; the deacidification tower 1 kettle liquid with most of the acid gas removed is pumped to the first tray on the top of the deamination tower 2; the top pressure of the deamination tower 2 is 0.23Mpa, the top temperature is 120℃, the bottom pressure is 0.26Mpa, and the bottom temperature is 128℃. After the ammonia vapor is stripped from the top of the deamination tower 2, a part of it enters the two-stage condensation device, and after two partial condensations, ammonia vapor with a concentration of 90% is obtained, which is sent to the flue gas desulfurization device for use; the deacidification tower 1 is not equipped with a reboiler, and another part of the ammonia vapor enters the kettle of the deacidification tower 1 and is used as the heat source of the deacidification tower 1; at the same time, part of the ammonia vapor after the first-stage condensation enters the ammonia vapor compressor 15 to increase the pressure to more than 0.24MPa and then enters the lower part of the deacidification tower 1; the kettle liquid of the deamination tower 2 is sent to the subsequent extraction and desulfurization device after heat exchange cooling. The deamination tower 2 is equipped with a reboiler and heated by heat transfer oil.

[0047] Compared with the traditional double-tower stripping process, the residual amount of hydrogen sulfide in the wastewater after treatment in this embodiment is reduced from more than 80 mg / L to less than 15 mg / L, and the total ammonia content is steadily reduced from the original 350 mg / L to less than 200 mg / L, meeting the requirements of subsequent treatment equipment.

[0048] The actual operation of the process using this embodiment is stable and reliable; the steam consumption for treating a ton of water is about 175 kg, which is about 75 kg lower than the traditional double-tower process originally used.

[0049] The above description is only a preferred embodiment of the present invention, and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art can still modify the technical solutions described in the above embodiments, or replace some of the technical features therein by equivalents. Any modification, equivalent replacement, modification, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A double-tower coupled coal chemical wastewater deacidification and deammoniation process, characterized in that: The cold and hot parts of the wastewater to be treated enter the deacidification tower from the upper part and the upper middle part respectively. The deacidification tower bottom liquid with most of the acidic gases removed is pumped to the upper part of the deamination tower. Both the deacidification tower and the deamination tower use a jet-state tray with the gas phase as the continuous phase and the liquid phase as the dispersed phase. After the ammonia-containing water vapor is stripped from the top of the deamination tower, one part enters the multi-stage condensation device, and the other part enters the deacidification tower bottom to be used as the heat source of the deacidification tower. The multi-stage condensation device comprises a first-stage condensation cooler and a first-stage liquid separation tank, wherein the first-stage liquid separation tank is connected to an ammonia vapor compressor, and the ammonia vapor compressor is connected to the deacidification tower kettle; When the organic matter content in the wastewater is particularly high or the ratio of the acid gas content to the ammonia content in the wastewater is greater than 2, start the ammonia vapor compressor to pressurize the treated part of the ammonia vapor to a pressure slightly higher than the deacidification tower kettle pressure before entering the lower part of the deacidification tower.

2. The process according to claim 1, characterized in that The multi-stage condensation device includes a primary condensation device, a secondary condensation device and a tertiary condensation device; The first-stage fractional condensation device includes a first-stage condensation cooler and a first-stage liquid separation tank connected in sequence; the second-stage fractional condensation device includes a first-stage condensation cooler, a first-stage liquid separation tank, a second-stage condensation cooler and a second-stage liquid separation tank connected in sequence; the third-stage fractional condensation device includes a first-stage condensation cooler, a first-stage liquid separation tank, a second-stage condensation cooler, a second-stage liquid separation tank, a third-stage condensation cooler and a third-stage liquid separation tank connected in sequence.

3. The process according to claim 2, characterized in that The upper gas phase outlet of the first-stage liquid separator is connected to an ammonia vapor compressor, and the ammonia vapor compressor is connected to the gas phase space of the deacidification tower kettle; After being treated by the primary condensation device, part of the ammonia-containing water vapor is pressurized to a pressure slightly higher than the deacidification tower bottom pressure and then enters the lower part of the deacidification tower; the deamination tower bottom liquid is sent to the subsequent treatment device after heat exchange cooling through the second centrifugal pump.

4. The process according to claim 1, characterized in that The lower liquid phase outlets of each liquid separation tank in the multi-stage liquid separation device are connected to the ammonia condensation cooler and the ammonia condensate tank. After the ammonia-containing water vapor is stripped out from the top of the deamination tower, a part of it enters the multi-stage condensation device. After multiple partial condensations, ammonia water vapor or crude ammonia gas of the required concentration is obtained, which is sent to the downstream device for processing or direct use through the third centrifugal pump.

5. The process according to claim 1, characterized in that The bottom liquid phase of the deacidification tower is connected to a first centrifugal pump, and the bottom liquid phase of the deammoniation tower is connected to a reboiler and a second centrifugal pump.

6. The process according to claim 1, characterized in that The top of the deacidification tower is connected to an acid gas condenser and an acid liquid separation tank in sequence. The acid gas enters the acid gas condenser from the top of the tower to be condensed, and then enters the subsequent treatment device after liquid separation in the acid liquid separation tank.

7. The process according to claim 1, characterized in that The number of theoretical plates of the deacidification tower is 8 to 20, and the top temperature of the deacidification tower is 40 to 120°C; the number of theoretical plates of the deamination tower is 15 to 35, and the top pressure of the deamination tower is 0.23 to 0.55 MPa, the top temperature is 120 to 150°C, the bottom pressure is 0.26 to 0.58 MPa, and the bottom temperature is 128 to 165°C.

8. The process according to claim 1, characterized in that The upper part and the middle upper part of the deacidification tower are respectively connected to the cold and hot feed pipelines, and the liquid phase outlet of the tower bottom is connected to the upper part of the deamination tower through the first centrifugal pump and the pipeline.

9. The process according to claim 1, characterized in that The wastewater to be treated is coal chemical wastewater containing acidic gas and ammonia.

Images