Double-tower coupled coal chemical wastewater deacidification and deamination process

Abstract

The present application belongs to the technical field of wastewater treatment and utilization, and relates to a coal chemical wastewater deacidification and deamination process coupled with double towers. The wastewater to be treated is divided into cold and hot parts, and is introduced into the tower from the upper part and the middle-upper part of the deacidification tower respectively. The deacidification tower kettle liquid from which most of the acid gases are removed is pumped to the upper part of the deamination tower. After the ammonia-containing water vapor is stripped from the top of the deamination tower, part of the ammonia-containing water vapor is introduced into a multi-stage condensation device, and the other part is introduced into the kettle of the deacidification tower and used as a heat source of the deacidification tower. The condensation device is also connected with an ammonia water vapor compressor. The ammonia-containing water vapor is pressurized to be slightly higher than the kettle pressure of the deacidification tower, and then is introduced into the deacidification tower. The process of the present application divides deacidification and deamination into two towers, and at the same time, the deacidification tower is not provided with a reboiler, but a part of the ammonia water vapor from the deamination tower is introduced into the deacidification tower, which provides a heat source on one hand, and on the other hand, through the disturbance of the gas, the reaction is more thorough, and the heat loss caused by the direct discharge of the exhaust gas from the top of the deacidification tower is reduced or prevented.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of wastewater treatment and utilization, and relates to a method for treating wastewater containing acid gas and ammonia, in particular to a coal chemical wastewater deacidification and deammoniation process coupled with double towers. BACKGROUND

[0002] In the process of coal conversion, a large amount of wastewater containing acid gas (including carbon dioxide, hydrogen sulfide, etc.) and ammonia will be produced. Since acid gas and ammonia will affect the subsequent biochemical treatment, it is necessary to separate and recycle them. The steam stripping method is the main commonly used technical method for removing acid gas and ammonia in current industrial processes, and generally includes single-tower stripping with side lines and double-tower stripping processes, which are widely used in enterprises. These processes have advantages and disadvantages, for example, the inventor applied for a Chinese patent CN1884150A in 2006, which disclosed a single-tower pressurized stripping method for treating coal gasification wastewater and its device. The single-tower stripping process with side lines often has problems such as side line liquid carrying, unstable control, etc., and it is difficult to scale up the device due to the height limitation.

[0003] The double-tower stripping process has no above-mentioned disadvantages, is relatively stable in operation, and has good scaling performance, but the steam consumption is relatively high. In order to reduce the energy consumption of the double-tower stripping process, the inventor introduced a double-effect technology into the double-tower stripping, and applied for a patent, i.e. Chinese patent CN102320671A, which disclosed a treatment method for wastewater containing acid and ammonia. In this method, ammonia water collected from the deammoniation tower is used as the heating medium of the reboiler of the deacidification tower instead of steam, thereby reducing the steam consumption per ton of water by 50-70 kg. However, the setting of this technology limits the deacidification to be carried out at a relatively low pressure, which limits its application scenarios. For example, when applied to wastewater with high ammonia content or high organic matter content, wastewater containing other basic components, and wastewater with high sulfide content, the deacidification efficiency is low, resulting in that the sulfide content of the effluent often exceeds the standard.

[0004] With the progress of coal chemical technology and the increasing production scale, the wastewater pollution load is becoming higher and higher, and the water quantity of a single project is also increasing. The increase of wastewater pollution load means the increase of organic matter concentration in wastewater. According to relevant data statistics, the higher the organic matter concentration, the greater the influence on the stripping efficiency of deacidification and deammoniation, so that the effluent is often unqualified or requires more energy consumption. When the wastewater quantity of a single project is large, it is hoped that the scale of the single series of the device can be scaled up in time to reduce the number of sets and reduce the management and operation cost. Based on the current situation, it is urgent to develop an energy-saving, stable, and good scaling performance deacidification and deammoniation process. SUMMARY

[0005] The present application aims at solving the above problems in the prior art, and provides a coal chemical wastewater deacidification and deamination process coupled with double towers.

[0006] The technical scheme of the present application is:

[0007] Through analysis, organic matters will accumulate on the gas-liquid interface to form a relatively rigid film layer, thereby inhibiting the mass transfer of ammonia between the gas-liquid phases. As the organic matter content of the wastewater is getting higher and higher, the inhibition has obviously affected the stripping effect. As the gas-liquid ratio in the deacidification process is smaller, the deacidification efficiency is more affected by the organic matters. In order to solve this problem, how to increase the disturbance between the gas-liquid two phases to promote the timely transfer of the molecular weak electrolyte into the gas phase is the key to improving the stripping effect. In order to achieve this purpose, the present application first selects a tray type with liquid phase as the dispersed phase, so that the liquid phase is broken into small droplets during the stripping process, promoting the disturbance between the phases. In addition, the residence time of the liquid phase on the tray is appropriately increased to break the diffusion bottleneck between the phases.

[0008] In addition, considering that the top temperature of the deacidification tower has an upper limit, measures need to be taken to ensure that the volume of the rising gas in the deacidification tower is increased under the condition that the heat contained in the stripping gas is constant. For this purpose, the present application proposes a strategy of directly introducing part of the tower top gas of the deamination tower into the deacidification tower as a heat source on the basis of the previous double tower technology. This strategy not only saves the reboiler of the deacidification tower, but also ensures that the stripping gas has a larger volume under the condition of constant heat, which can play a greater disturbance role on the liquid phase during the stripping process. In the scheme, the primary ammonia water vapor is compressed and returned, further increasing the volume of the rising gas in the deacidification tower and increasing the disturbance effect.

[0009] Based on this, the present application provides a coal chemical wastewater deacidification and deamination process coupled with double towers. The wastewater to be treated is divided into cold and hot parts, which are introduced into the upper part and the middle-upper part of the deacidification tower, respectively. The deacidification tower and the deamination tower both adopt a jet tray with gas phase as the continuous phase and liquid phase as the dispersed phase. After the ammonia-containing water vapor is stripped from the top of the deamination tower, part of it enters a multi-stage condensation device, and the other part enters the deacidification tower as a heat source for the deacidification tower.

[0010] The multi-stage condensation device includes a primary condensing cooler and a primary liquid separation tank. The primary liquid separation tank is connected to an ammonia water vapor compressor, and the ammonia water vapor compressor is connected to the deacidification tower.

[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, the ammonia water vapor compressor is started, and the treated part of the ammonia-containing water vapor is pressurized to slightly higher than the pressure of the bottom of the deacidification tower and then enters the lower part of the deacidification tower.

[0012] Further, the multi-stage partial condensation device comprises a first-stage partial condensation device, a second-stage partial condensation device and a third-stage partial condensation device.

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

[0014] Further, the gas phase outlet at the upper part of the first-stage liquid separation tank is connected with the ammonia water vapor compressor, and the ammonia water vapor compressor is connected with the gas phase space of the bottom of the deacidification tower.

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

[0016] Further, the liquid phase outlets at the lower parts of the liquid separation tanks in the multi-stage partial condensation device are connected with an ammonia condensing cooler and an ammonia condensate tank; after the ammonia-containing water vapor is stripped from the top of the deaminating tower, part of the ammonia-containing water vapor enters the multi-stage partial condensation device, is partially condensed for multiple times to obtain ammonia water vapor or crude ammonia gas with a required concentration, and is sent to a downstream device for processing or directly used through a third centrifugal pump.

[0017] Further, a first centrifugal pump is connected with the liquid phase at the bottom of the deacidification tower, and a reboiler and a second centrifugal pump are connected with the liquid phase at the bottom of the deaminating tower.

[0018] Further, an acid gas condenser and an acid liquid separation tank are connected with the top of the deacidification tower in sequence; the acid gas from the top of the tower enters the acid gas condenser for condensation, is separated through the acid liquid separation tank, and then enters a subsequent treatment device.

[0019] Further, the number of theoretical plates of the deacidification tower is 8-20, and the temperature at the top of the deacidification tower is 40-120℃; the number of theoretical plates of the deaminating tower is 15-35, the pressure at the top of the deaminating tower is 0.23-0.55 Mpa, the temperature at the top of the deaminating tower is 120-150℃, the pressure at the bottom of the deaminating tower is 0.26-0.58 Mpa, and the temperature at the bottom of the deaminating tower is 128-165℃.

[0020] Further, the upper part and the upper-middle part of the deacidification tower are respectively connected with cold and hot feed pipelines, and the liquid phase outlet of the tower kettle is connected with the upper part of the deamination tower through a first centrifugal pump and a pipeline.

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

[0022] The beneficial effects of the present application are:

[0023] (1) The process flow of the present application separates deacidification and deamination into two towers, and the deacidification tower does not have a reboiler, but selects a part of ammonia water vapor from the deamination tower to enter the deacidification tower, which provides heat source on one hand, and on the other hand, increases the volume of the rising gas under the condition that the total heat of the rising gas is constant and the tower top temperature of the deacidification tower does not exceed the standard. In addition, the primary ammonia water vapor is compressed and returned to flow in the present application, which further increases the volume of the rising gas in the deacidification tower. In the case of a jet tray, the increase of the volume of the rising gas can enhance the disturbance between the gas and liquid phases, so that the dissociation reaction of ammonia and acid gas in the liquid phase is fast, and the barrier effect of organic matter between the gas and liquid phases is broken, thereby significantly improving the deacidification efficiency. At the same time, this scheme has the advantages of stable and reliable 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 application is equivalent to that of the single-tower process with side line extraction, both of which are relatively energy-saving, but the stability is better than that of the single-tower process with side line extraction, and there is no side line liquid problem. When the device is large-sized, separating deacidification and deamination by using the present application can avoid the problem of limited tower height, and improve the safety and stability of the device, so the process can be widely applied to large-scale stripping treatment devices for coal chemical wastewater.

[0025] (3) Coal chemical wastewater is prone to pollution and blockage in the deamination section during deacidification and deamination. If the present application is used, only the deamination tower needs to be opened during shutdown and cleaning, which reduces the maintenance workload and avoids the risk of spontaneous combustion after the deacidification tower is in contact with air. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 The present application provides a schematic diagram of the structure and principle of a double-tower coupled coal chemical wastewater deacidification and deamination process;

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

[0028] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of the present application.

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

[0030] As shown in the drawings, Figure 1 The present application provides a double-tower coupled coal chemical wastewater deacidification and deamination process. The process uses a deacidification tower 1 and a deamination tower 2 coupling device. The theoretical plate number of the deacidification tower 1 is 8-20, and the theoretical plate number of the deamination tower 2 is 15-35. The process steps are as follows:

[0031] The wastewater containing acid and ammonia to be treated is divided into cold and hot parts, which are respectively introduced into the deacidification tower 1 from the upper part and the upper-middle part of the tower through cold and hot feed pipelines, and the tower top temperature of the deacidification tower 1 is adjusted and controlled to be 40-120℃. The acid gas is discharged from the tower top, and then sequentially passes through the acid gas condenser 13 and the acid liquid separation tank 14 connected with the tower top of the deacidification tower 1, and after condensation and separation, enters the subsequent treatment device.

[0032] The deacidification tower 1 kettle liquid from which most of the acid gas is removed is pumped to the first block of the deamination tower 2 through the first centrifugal pump 10. The tower top pressure of the deamination tower 2 is 0.23-0.55 MPa, the tower top temperature is 120-150℃, the tower bottom pressure is 0.26-0.58 MPa, and the tower bottom temperature is 128-165℃. At this time, the tower top pressure of the deacidification tower 1 is 0.2-0.5 MPa, the tower top temperature is 40-120℃, the tower bottom pressure is 0.22-0.52 MPa, and the tower bottom temperature is 120-149℃.

[0033] After the ammonia-containing water vapor is stripped from the top of the deamination tower 2, part of it enters the multi-stage condensation device (composed of part or all of the first-stage condensation cooler 3, the first-stage liquid separation tank 4, the second-stage condensation cooler 5, the second-stage liquid separation tank 6, the third-stage condensation cooler 7, and the third-stage liquid separation tank 8 connected in series), and after multiple partial condensations in the ammonia condensation cooler and the ammonia condensate tank 9, ammonia water vapor or crude ammonia gas with 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 taken from the top of the deamination tower 2 enters the kettle of the deacidification tower 1 and is used as the heat source of the deacidification tower 1. The deacidification tower 1 is not provided with a reboiler.

[0034] For the ammonia-containing water system with very high content of organic matter or the ratio of acid gas content to ammonia content greater than 2, part of the ammonia water vapor after the first condensation (i.e. through the first condenser 3 and the first liquid separator 4) is simultaneously lifted to 0.24-0.54 MPa (the pressure is slightly higher than the pressure of the bottom of the deacidification tower 0.22-0.52 MPa) by the ammonia water vapor compressor 15, and then enters the lower part of the deacidification tower 1; part of the bottom liquid of the deammoniation tower 2 after extraction is sent to a subsequent treatment device after heat exchange and cooling. The deammoniation tower 2 is provided with a reboiler and heated by external heat utilities.

[0035] Example 1

[0036] A certain coking and tar processing enterprise in Shaanxi needs to treat 120 tons of acid-containing and ammonia-containing 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 application is used for deacidification and deammoniation treatment, wherein the theoretical plate number of the deacidification tower 1 and the deammoniation tower 2 is 20 and 35 respectively.

[0037] The deacidification and deammoniation process steps of this example are as follows: the wastewater is divided into cold and hot parts and enters the tower from the upper part and the middle-upper part of the deacidification tower 1 respectively, and the top pressure of the deacidification tower 1 is adjusted and controlled to be 0.5 MPa, and the top temperature is 120℃; the bottom pressure of the deammoniation tower 2 is 0.52 Mpa, and the bottom temperature is 149℃. The acid gas comes out from the top of the tower, is condensed and separated, and then enters the subsequent sulfur recovery device; the deacidification tower 1 liquid that has removed most of the acid gas is pumped to the upper part of the first tray of the deammoniation tower 2; the top pressure of the deammoniation tower 2 is 0.55 Mpa, and the top temperature is 120-150℃, the bottom pressure is 0.58 Mpa, and the bottom temperature is 165℃. After the ammonia-containing water vapor is stripped from the top of the deammoniation tower 2, part of it enters the three-stage condensation device, and after multiple partial condensations, crude ammonia gas is obtained and sent to the denitration device; the deacidification tower 1 is not provided with a reboiler, and the other part of the ammonia water vapor enters the deacidification tower 1 for use as a heat source; the deammoniation tower 2 liquid is cooled by heat exchange and then sent to a subsequent extraction and dephenolization device. The deammoniation tower 2 is provided with a reboiler and heated by 1.0 MPa steam.

[0038] After the above treatment, the residual amount of hydrogen sulfide in the wastewater is less than 15 mg / L, and the total ammonia content is less than 100 mg / L, which meets the specified standard. 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-SNG enterprise in Inner Mongolia, a new set of double-tower coupled stripping process of the invention is built, and the single device scale is 400 tons / hour. The original waste water contains about 150 mg / L of hydrogen sulfide, about 16000 mg / L of carbon dioxide, and about 14000 mg / L of ammonia. The double-tower coupled device of the invention is used for deacidification and deamination treatment, wherein the theoretical plate number of the deacidification tower 1 and the deamination tower 2 is 15 and 28 respectively.

[0041] The process steps are as follows: the waste water is divided into cold and hot parts, which are respectively introduced into the deacidification tower 1 from the upper part and the middle and upper part of the tower, and the tower top pressure of the deacidification tower 1 is controlled to be 0.2 MPa, and the tower top temperature is controlled to be 60℃, and the bottom pressure of the deamination tower 2 is 0.22 Mpa, and the bottom temperature is 120℃. The acid gas is discharged from the tower top and enters the subsequent treatment device; the deacidification tower 1 liquid is pumped to the upper part of the deamination tower 2 and the first tower tray; the tower top pressure of the deamination tower 2 is 0.23 Mpa, the tower top temperature is 120℃, the tower bottom pressure is 0.26 Mpa, and the tower bottom temperature is 128℃. The ammonia-containing water vapor is stripped from the top of the deamination tower 2, part of which enters the two-stage condensation device, and after two times of partial condensation, ammonia water vapor with a concentration of 90% is obtained and sent to the flue gas desulfurization device; the deacidification tower 1 is not provided with a reboiler, and the other part of the ammonia water vapor enters the deacidification tower 1 tower kettle and is used as the heat source of the deacidification tower 1; the deamination tower 2 kettle liquid is cooled by heat exchange and then sent to the subsequent extraction device. The deamination tower 2 is provided with a reboiler and heated by 0.5 MPa steam.

[0042] After the above treatment, the residual amount of hydrogen sulfide 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 specified standard.

[0043] The enterprise generates 1520 tons of acid-containing and ammonia-containing waste water per hour. In addition to the 400 tons / hour device of the invention, there are four earlier built treatment devices, two of which are 280 tons / hour devices using the traditional double-tower process, and the other two are 280 tons / hour devices using the energy-saving double-tower stripping process of the patent CN102320671A. The process device of the invention is more efficient, stable and reliable in actual operation, and the content of hydrogen sulfide and acid gas after treatment is only 30-40% of that of the original four devices; in terms of energy consumption, the steam consumption per ton of water treated by the invention is about 188 kg, which is 60 kg lower than that of the device using the traditional double-tower process, and is equivalent to that of the invention CN102320671A. At the same time, the device is currently the largest deacidification and deamination device in the world, which shows that the process has excellent scale stability.

[0044] Example 3

[0045] A certain enterprise in Yulin, which is engaged in the treatment of waste water from coal gasification, needs to treat 500 tons of waste water containing acid and ammonia per hour, and the scale of a single device is 250 tons / hour; the waste water contains about 800 mg / L of hydrogen sulfide, about 3000 mg / L of carbon dioxide, and about 5000 mg / L of ammonia, and the organic matter content of the waste water is particularly high, with COD exceeding 50000 mg / L. The original device adopts a traditional double-tower stripping process, but the steam consumption is high and the treatment effect is not ideal. The original device is modified by using the technology designed in the present application, and the modified device is a double-tower coupled device, wherein the theoretical plate number of the acid removal tower 1 and the ammonia removal tower 2 is 15 and 28 respectively.

[0046] The process steps after modification are as follows: the waste water is divided into cold and hot parts and enters the acid removal tower 1 from the upper part and the middle and upper parts of the tower respectively, and the tower top pressure of the acid removal tower 1 is adjusted and controlled to be 0.2 MPa, and the tower top temperature is 60℃; the bottom pressure of the ammonia removal tower 2 is 0.22 Mpa, and the bottom temperature is 120℃. The acid gas comes out from the tower top and enters the subsequent treatment device; the kettle liquid of the acid removal tower 1, from which most of the acid gas has been removed, is pumped to the upper part of the first tray of the ammonia removal tower 2; the tower top pressure of the ammonia removal tower 2 is 0.23 Mpa, and the tower top temperature is 120℃, and the tower bottom pressure is 0.26 Mpa, and the tower bottom temperature is 128℃. The ammonia water vapor from the top of the ammonia removal tower 2 is partially condensed twice in a two-stage condensing device to obtain ammonia water vapor with a concentration of 90%, which is sent to a flue gas desulfurization device for use; the acid removal tower 1 is not provided with a reboiler, and the other part of the ammonia water vapor enters the kettle of the acid removal tower 1 to serve as the heat source of the acid removal tower 1; at the same time, part of the ammonia water vapor after the first-stage condensation is pressurized to 0.24 MPa or above by an ammonia water vapor compressor 15 and then enters the lower part of the acid removal tower 1; the kettle liquid of the ammonia removal tower 2 is cooled by heat exchange and then sent to a subsequent extraction device. The ammonia removal tower 2 is provided with a reboiler heated by heat-conducting oil.

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

[0048] The process of the present embodiment is actually stable and reliable in operation; the steam consumption for treating one ton of water is about 175 kg, which is about 75 kg lower than that of the original traditional double-tower process.

[0049] The above description is only the preferred embodiments of the present application, and is not intended to limit the present application. Although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art will appreciate that the technical solutions recorded in the foregoing embodiments can be modified, or some technical features can be replaced by equivalent features. Any modification, equivalent replacement, modification, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A dual-column coupled coal chemical wastewater deacidification and deamination process, characterized in that, The wastewater to be treated is divided into cold and hot parts, which are respectively introduced into the upper part and the middle-upper part of the deacidification tower, the deacidification tower kettle liquid with most of the acid gas removed is pumped to the upper part of the deamination tower, the deacidification tower and the deamination tower both use the gas phase as the continuous phase and the liquid phase as the dispersed phase of the jet state tray; after the ammonia-containing water vapor is stripped from the top of the deamination tower, part of it enters the multi-stage condensation device, and the other part enters the deacidification tower kettle and is 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, the first-stage liquid separation tank is connected with an ammonia water vapor compressor, and the ammonia water vapor compressor is connected with the deacidification tower kettle. When the COD in the wastewater exceeds 50000 mg / L or the ratio of the acid gas content to the ammonia content in the wastewater is greater than 2, the ammonia water vapor compressor is started, and the treated part of the ammonia-containing water vapor is pressurized to slightly higher than the pressure of the deacidification tower kettle and then enters the lower part of the deacidification tower.

2. The process according to claim 1, characterized in that, The multi-stage condensation device comprises a first-stage condensation device, a second-stage condensation device and a third-stage condensation device. The first-stage condensation device comprises a first-stage condensation cooler and a first-stage liquid separation tank connected in sequence; the second-stage condensation device comprises 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; and the third-stage condensation device comprises 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 separation tank is connected with the ammonia water vapor compressor, and the ammonia water vapor compressor is connected with the gas phase space of the deacidification tower kettle. The part of the ammonia-containing water vapor treated by the first-stage condensation device is pressurized to slightly higher than the pressure of the deacidification tower kettle and then enters the lower part of the deacidification tower; and the deamination tower kettle liquid is sent to a subsequent treatment device after being cooled by heat exchange through a second centrifugal pump.

4. The process of claim 1, wherein, The lower liquid phase outlets of the liquid separation tanks in the multi-stage condensation device are all connected with an ammonia condensation cooler and an ammonia condensate tank, after the ammonia-containing water vapor is stripped from the top of the deamination tower, part of it enters the multi-stage condensation device, and the required concentration of ammonia water vapor or crude ammonia gas is obtained after multiple partial condensations, and is sent to a downstream device for processing or directly used.

5. The process of claim 1, wherein, The liquid phase of the kettle of the deacidification tower is connected with a first centrifugal pump, and the liquid phase of the kettle of the deamination tower is connected with a reboiler and a second centrifugal pump.

6. The process of claim 1, wherein, The top of the deacidification tower is sequentially connected with an acid gas condenser and an acid liquid separation tank, the acid gas from the top enters the acid gas condenser for condensation, then is separated through the acid liquid separation tank and enters a subsequent treatment device.

7. The process of claim 1, wherein, The theoretical plate number of the deacidification tower is 8-20, and the tower top temperature of the deacidification tower is 40-120℃; the theoretical plate number of the deamination tower is 15-35, the tower top pressure of the deamination tower is 0.23-0.55 Mpa, the tower top temperature is 120-150℃, the tower bottom pressure is 0.26-0.58 Mpa, and the tower bottom temperature is 128-165℃.

8. The process of claim 1, wherein, The upper part and the middle-upper part of the deacidification tower are respectively connected with cold and hot feed pipelines, and the liquid phase outlet of the kettle is connected with the upper part of the deamination tower through a first centrifugal pump and a pipeline.

9. The process of claim 1, wherein, The wastewater to be treated is coal chemical wastewater containing acid gas and ammonia.

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