Waste heat total recovery type ammonia-nitrogen wastewater flash evaporation stripping system

Abstract

The utility model discloses a waste heat full recovery type ammonia-nitrogen wastewater flash steam stripping system which comprises a steam stripping device, a waste heat recovery device and an ultra-high temperature heat pump, and the steam stripping device comprises a flash steam stripping tower; the waste heat recovery device is used for recovering condensation heat of steam at the top of the flash steam stripping tower, heat of ammonia water in the tower, heat of discharged wastewater and waste heat of flue gas of a factory kiln or a boiler; the ultra-high-temperature heat pump is used for transferring the recycled heat into low-concentration ammonia-nitrogen wastewater discharged from the bottom of the flash steam stripping tower to heat the low-concentration ammonia-nitrogen wastewater, and the heated low-concentration ultra-high-temperature ammonia-nitrogen wastewater is introduced into the lower part of the flash steam stripping tower to flash steam to perform steam stripping and ammonia distillation on the high-concentration ammonia-nitrogen wastewater. The system has the beneficial effects that the system can perform steam stripping on ammonia nitrogen wastewater without using or reducing external steam, and does not need to use a refrigerating unit and a circulating cooling tower for cooling, so that the operation cost of steam stripping ammonia distillation is saved.

Description

Technical Field

[0001] The utility model relates to the field of wastewater ammonia distillation, in particular to a waste heat full recovery type ammonia nitrogen wastewater flash steam stripping system. Background Art

[0002] In the production process of power batteries, chemicals, pharmaceuticals, coking and other industries, a large amount of ammonia nitrogen wastewater is generated. In order to extract ammonia from the wastewater by distillation, low-pressure steam is required to flash strip the ammonia nitrogen wastewater. The steam in the traditional stripping process is provided by gas or coal-fired steam boilers in the plant area. The fuel consumption cost is high and the environment is polluted due to the combustion of the fuel.

[0003] In addition, in the traditional stripping process, the partial condenser at the outlet of the ammonia distillation tower uses circulating cooling water to condense the water vapor mixed with the ammonia vapor. To maintain the ammonia absorption efficiency and heat balance in the absorption tower, low-temperature water is produced by a refrigeration unit and a circulating water cooling tower to cool the ammonia water in the absorption tower. The latent heat of the water vapor and the heat of the ammonia water in the absorption tower are carried away by the circulating cooling water and dissipated into the ambient atmosphere, thus being wasted. At the same time, the wastewater after flash stripping of ammonia nitrogen wastewater is approximately 40-50°C when it enters the subsequent wastewater treatment process, and there is room for recycling and reuse of the remaining heat. Utility Model Content

[0004] The purpose of this utility model is to overcome the above technical deficiencies and propose a waste heat full recovery ammonia nitrogen wastewater flash steam stripping system to solve the technical problems of high operating cost of wastewater ammonia distillation, serious environmental pollution and insufficient utilization of waste heat in the existing technology.

[0005] In order to achieve the above technical purpose, the present invention adopts the following technical solutions:

[0006] The utility model provides a waste heat full recovery type ammonia nitrogen wastewater flash steam stripping system, comprising:

[0007] a stripping device comprising a flash stripping tower;

[0008] A waste heat recovery device, which is used to recover the condensation heat of the top steam of the flash steam stripping tower, the heat of the ammonia water in the tower, the heat of the discharged waste water, and the waste heat of the flue gas from the kiln or boiler in the factory area; and

[0009] The ultra-high temperature heat pump is used to transfer the recovered heat to the low-concentration ammonia nitrogen wastewater discharged from the bottom of the flash steam stripping tower to heat it up. The heated low-concentration ultra-high temperature ammonia nitrogen wastewater is passed into the bottom of the flash steam stripping tower to flash out steam to strip the high-concentration ammonia nitrogen wastewater and evaporate ammonia.

[0010] In some embodiments, the stripping device also includes a wastewater preheater, a wastewater reheater, a high-concentration ammonia nitrogen wastewater tank and a feed pump. One side of the wastewater preheater is a high-concentration ammonia nitrogen wastewater inlet and outlet, and the other side is a circulating hot water inlet and outlet. One side of the wastewater reheater is a high-concentration ammonia nitrogen wastewater inlet and outlet, and the other side is a low-concentration ammonia nitrogen wastewater inlet and outlet. The flash steam stripping tower includes an ammonia nitrogen wastewater inlet in the middle and upper part, an ammonia nitrogen wastewater outlet at the bottom of the tower, an ultra-high temperature wastewater inlet at the bottom, a steam outlet at the top of the tower, and a reflux liquid inlet at the top.

[0011] In some embodiments, the high-concentration ammonia nitrogen wastewater tank is connected to the inlet of the feed pump, the outlet of the feed pump is connected to the high-concentration ammonia nitrogen wastewater inlet of the wastewater preheater, the high-concentration ammonia nitrogen wastewater outlet of the wastewater preheater is connected to the high-concentration ammonia nitrogen wastewater inlet of the wastewater reheater, and the high-concentration ammonia nitrogen wastewater outlet of the wastewater reheater is connected to the ammonia nitrogen wastewater inlet of the flash steam stripping tower.

[0012] In some embodiments, the waste heat recovery device includes a medium- and high-temperature heat pump, a forced circulation pump at the bottom of the tower, a first tee, a wastewater treatment tank, a condensation heat recovery device at the top of the tower, a reflux tank, a medium- and low-temperature heat pump, an absorption tower, a reflux pump, an ammonia pump, a second tee, and a concentrated ammonia tank;

[0013] One side of the medium and high temperature heat pump is for the inlet and outlet of low concentration ammonia nitrogen wastewater, and the other side is for the inlet and outlet of circulating hot water;

[0014] The ammonia nitrogen wastewater outlet of the flash steam stripping tower is connected to the inlet of the tower bottom forced circulation pump, the outlet of the tower bottom forced circulation pump is connected to the first interface of the first tee, the second interface of the first tee is connected to the low-concentration ammonia nitrogen wastewater inlet of the wastewater reheater, the low-concentration ammonia nitrogen wastewater outlet of the wastewater reheater is connected to the ammonia nitrogen wastewater inlet of the medium and high temperature heat pump, the ammonia nitrogen wastewater outlet of the medium and high temperature heat pump is connected to the wastewater treatment tank, the third interface of the first tee is connected to the ammonia nitrogen wastewater inlet of the ultra-high temperature heat pump, and the ammonia nitrogen wastewater outlet of the ultra-high temperature heat pump is connected to the ultra-high temperature wastewater inlet of the flash steam stripping tower;

[0015] The tower top condensation heat recovery device has a steam inlet, a circulating hot water inlet and outlet, and a two-phase fluid outlet. The steam outlet of the flash steam stripping tower is connected to the steam inlet of the tower top condensation heat recovery device, and the circulating hot water inlet and circulating hot water outlet of the tower top condensation heat recovery device are respectively connected to the circulating hot water outlet and circulating hot water inlet of the ultra-high temperature heat pump;

[0016] The reflux tank has a two-phase fluid inlet, a reflux port, and an ammonia vapor outlet. One side of the medium and low temperature heat pump is an ammonia inlet and outlet, and the other side is a circulating water inlet and outlet. The circulating water inlet and the circulating water outlet of the medium and low temperature heat pump are respectively connected to the circulating water inlet and outlet of the wastewater preheater. The circulating hot water outlet of the medium and high temperature heat pump is connected to the pipeline between the circulating hot water outlet of the tower top condensing heat recovery device and the circulating hot water inlet of the ultra-high temperature heat pump through a pipeline. The circulating hot water inlet of the medium and high temperature heat pump is connected to the pipeline between the circulating hot water outlet of the ultra-high temperature heat pump and the circulating hot water inlet of the tower top condensing heat recovery device through a pipeline.

[0017] The absorption tower comprises an ammonia vapor inlet at the bottom, an ammonia water outlet at the bottom, an ammonia water inlet in the middle, and a non-condensable gas outlet at the top;

[0018] The two-phase fluid outlet of the tower top condensing heat recovery device is connected to the two-phase fluid inlet of the reflux tank, the reflux port of the reflux tank is connected to the inlet of the reflux pump, the outlet of the reflux pump is connected to the reflux liquid inlet of the flash steam stripping tower, and the ammonia vapor outlet of the reflux tank is connected to the ammonia vapor inlet of the absorption tower;

[0019] The ammonia outlet of the absorption tower is connected to the inlet of the ammonia pump, and the outlet of the ammonia pump is connected to the ammonia inlet of the medium and low temperature heat pump;

[0020] The ammonia outlet of the medium- and low-temperature heat pump is communicated with the first interface of the second tee, and the second interface of the second tee is communicated with the concentrated ammonia tank.

[0021] In some embodiments, the two-phase fluid outlet of the tower top condensation heat recovery device is connected to the two-phase fluid inlet of the reflux tank via a first connecting pipe.

[0022] In some embodiments, the reflux port of the reflux tank is connected to the inlet of the reflux pump via a second connecting pipe.

[0023] In some embodiments, the outlet of the reflux pump is connected to the reflux liquid inlet of the flash steam stripping tower via a third connecting pipe.

[0024] In some embodiments, the ammonia vapor outlet of the reflux tank is connected to the ammonia vapor inlet of the absorption tower via a fourth connecting pipe.

[0025] In some embodiments, the ammonia water outlet of the absorption tower is connected to the inlet of the ammonia water pump via a fifth connecting pipe.

[0026] In some embodiments, the outlet of the aqueous ammonia pump is connected to the aqueous ammonia inlet of the medium- and low-temperature heat pump via a sixth connecting pipe.

[0027] Compared with the prior art, the beneficial effect of the waste heat full recovery type ammonia-nitrogen wastewater flash stripping system is that the condensation heat of the tower top vapor in the traditional ammonia-nitrogen wastewater stripping process, the ammonia water heat in the absorption tower, the wastewater heat discharged after the stripping is finished and the waste heat of the kiln or boiler flue gas in the factory are fully recovered, the heat of the circulating hot water is transferred to the low-concentration ammonia-nitrogen wastewater discharged from the bottom of the flash stripping tower by the ultrahigh-temperature heat pump to heat the low-concentration ultrahigh-temperature ammonia-nitrogen wastewater, and the heated low-concentration ultrahigh-temperature ammonia-nitrogen wastewater is introduced into the lower part of the flash stripping tower to flash out the vapor to strip the ammonia from the high-concentration ammonia-nitrogen wastewater. The system can not use or reduce the use of external steam to strip the ammonia-nitrogen wastewater, and does not need to use a refrigerating unit and a circulating cooling tower to cool, so that the operation cost of stripping and ammonia evaporation is saved. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 is a structural schematic view of the waste heat full recovery type ammonia-nitrogen wastewater flash stripping system provided by an embodiment of the utility model;

[0029] The reference signs are explained as follows: 1-stripping device, 11-wastewater preheater, 12-wastewater reheater, 13-flash stripping tower, 14-high-concentration ammonia-nitrogen wastewater tank, 15-feeding pump, 2-waste heat recovery device, 21-medium-high-temperature heat pump, 22-bottom forced circulation pump, 23-first three-way joint, 24-wastewater treatment tank, 25-tower top condensation heat recovery device, 26-reflux tank, 27-medium-low-temperature heat pump, 28-absorption tower, 29-reflux pump, 210-ammonia water pump, 211-second three-way joint, 212-concentrated ammonia tank, 3-ultrahigh-temperature heat pump. DETAILED DESCRIPTION

[0030] In order to make the purpose, technical scheme and advantages of the utility model more clearly, the utility model is further described in detail below by combining with the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the utility model, and are not used to limit the utility model.

[0031] In order to solve the technical problems of high operation cost, serious environmental pollution and insufficient utilization of waste heat in wastewater ammonia evaporation, the utility model provides a waste heat full recovery type ammonia-nitrogen wastewater flash stripping system, which can realize stripping of ammonia-nitrogen wastewater without using or reducing the use of external steam.

[0032] Please refer to Figure 1 , Figure 1 is a structural schematic view of the waste heat full recovery type ammonia-nitrogen wastewater flash stripping system in an embodiment of the utility model, and the waste heat full recovery type ammonia-nitrogen wastewater flash stripping system comprises a stripping device 1, a waste heat recovery device 2 and an ultrahigh-temperature heat pump 3.

[0033] The stripping device 1 comprises a flash stripping tower 13, which is a device for removing ammonia nitrogen in wastewater treatment. Its core working principle is to use high-temperature wastewater (usually low-concentration ammonia nitrogen wastewater after flash stripping, which is heated by some means such as ultra-high-temperature heat pump) to generate steam by flashing in the lower part of the tower. These vapors then contact with high-concentration ammonia nitrogen wastewater, thereby promoting the transfer of ammonia nitrogen from wastewater to steam, achieving the removal of ammonia nitrogen.

[0034] The stripping device 1 further comprises a wastewater preheater 11, a wastewater reheater 12, a high-concentration ammonia nitrogen wastewater tank 14, and a feed pump 15. One side of the wastewater preheater 11 is the high-concentration ammonia nitrogen wastewater inlet and outlet, and the other side is the circulating hot water inlet and outlet. One side of the wastewater reheater 12 is the high-concentration ammonia nitrogen wastewater inlet and outlet, and the other side is the low-concentration ammonia nitrogen wastewater inlet and outlet. The flash stripping tower 13 comprises an ammonia nitrogen wastewater inlet in the upper middle part, an ammonia nitrogen wastewater outlet at the bottom, an ultra-high-temperature wastewater inlet in the lower part, a vapor outlet at the top, and a reflux liquid inlet in the upper part.

[0035] The high-concentration ammonia nitrogen wastewater tank 14 is in communication with the inlet of the feed pump 15. The outlet of the feed pump 15 is in communication with the high-concentration ammonia nitrogen wastewater inlet of the wastewater preheater 11. The high-concentration ammonia nitrogen wastewater outlet of the wastewater preheater 11 is in communication with the high-concentration ammonia nitrogen wastewater inlet of the wastewater reheater 12. The high-concentration ammonia nitrogen wastewater outlet of the wastewater reheater 12 is in communication with the ammonia nitrogen wastewater inlet of the flash stripping tower 13.

[0036] The waste heat recovery device 2 is used to recover the condensation heat of the tower top vapor of the flash stripping tower 13, the ammonia water heat in the tower, the heat of the discharged wastewater, and the waste heat of the kiln or boiler flue gas in the plant area.

[0037] The ultra-high-temperature heat pump 3 is used to transfer the recovered heat to the low-concentration ammonia nitrogen wastewater discharged from the bottom of the flash stripping tower 13 to warm it up. The low-concentration ultra-high-temperature ammonia nitrogen wastewater after warming is introduced into the lower part of the flash stripping tower 13 to flash out steam for stripping ammonia from the high-concentration ammonia nitrogen wastewater. One side of the ultra-high-temperature heat pump 3 is the ammonia nitrogen wastewater inlet and outlet, and the other side is the circulating hot water inlet and outlet. The ultra-high-temperature heat pump 3 is an electric heat pump or a second type of absorption heat pump.

[0038] The waste heat recovery device 2 comprises a medium-high-temperature heat pump 21, a tower bottom forced circulation pump 22, a first three-way valve 23, a wastewater treatment tank 24, a tower top condensation heat recovery device 25, a reflux tank 26, a medium-low-temperature heat pump 27, an absorption tower 28, a reflux pump 29, an ammonia water pump 210, a second three-way valve 211, and a concentrated ammonia tank 212.

[0039] One side of the medium-high-temperature heat pump 21 is the low-concentration ammonia nitrogen wastewater inlet and outlet, and the other side is the circulating hot water inlet and outlet. The medium-high-temperature heat pump 21 can be driven by electricity, steam, or gas.

[0040] The ammonia nitrogen wastewater outlet of the flash steam stripping tower 13 is connected to the inlet of the tower bottom forced circulation pump 22, the outlet of the tower bottom forced circulation pump 22 is connected to the first interface of the first tee 23, the second interface of the first tee 23 is connected to the low-concentration ammonia nitrogen wastewater inlet of the wastewater reheater 12, the low-concentration ammonia nitrogen wastewater outlet of the wastewater reheater 12 is connected to the ammonia nitrogen wastewater inlet of the medium and high temperature heat pump 21, the ammonia nitrogen wastewater outlet of the medium and high temperature heat pump 21 is connected to the wastewater treatment tank 24, the third interface of the first tee 23 is connected to the ammonia nitrogen wastewater inlet of the ultra-high temperature heat pump 3, and the ammonia nitrogen wastewater outlet of the ultra-high temperature heat pump 3 is connected to the ultra-high temperature wastewater inlet of the flash steam stripping tower 13.

[0041] During use, the high-concentration ammonia nitrogen wastewater at a temperature of about 20-30°C in the high-concentration ammonia nitrogen wastewater tank 14 is initially precipitated and pretreated, and then enters the wastewater preheater 11 through the feed pump 15 and is preheated to about 30-50°C with the circulating hot water in the wastewater preheater 11. The preheated high-concentration ammonia nitrogen wastewater then enters the wastewater reheater 12.

[0042] The low-concentration ammonia nitrogen wastewater at the bottom of the flash stripping tower 13, which has been stripped to a temperature of about 102-105°C and an ammonia concentration of about 30-50 ppm, enters the wastewater reheater 12 through the bottom forced circulation pump 22, and the other part enters the ammonia nitrogen wastewater side of the ultra-high temperature heat pump 3.

[0043] The low-concentration ammonia nitrogen wastewater entering the wastewater reheater 12 and the high-concentration ammonia nitrogen wastewater undergo a partition-type heat exchange internally, so that the temperature of the high-concentration ammonia nitrogen wastewater rises to about 70-100°C and enters the flash steam stripping tower 13. After the heat exchange, the low-concentration ammonia nitrogen wastewater enters the medium- and high-temperature heat pump 21 and releases heat to the circulating hot water entering the medium- and high-temperature heat pump 21, and then the temperature drops to about 30-40°C and is discharged into the wastewater treatment pool 24.

[0044] The top condensing heat recovery unit 25 has a steam inlet, a circulating hot water inlet and outlet, and a two-phase fluid outlet. The steam outlet of the flash steam stripping tower 13 is connected to the steam inlet of the top condensing heat recovery unit 25. The circulating hot water inlet and outlet of the top condensing heat recovery unit 25 are connected to the circulating hot water outlet and circulating hot water inlet of the ultra-high temperature heat pump 3, respectively.

[0045] The reflux tank 26 has a two-phase fluid inlet, a reflux port, and an ammonia vapor outlet. One side of the medium- and low-temperature heat pump 27 is an ammonia water inlet and outlet, and the other side is a circulating water inlet and outlet. The circulating water inlet and circulating water outlet of the medium- and low-temperature heat pump 27 are respectively connected to the circulating water inlet and outlet of the wastewater preheater 11. The medium- and low-temperature heat pump 27 can be driven by electricity, steam, or gas. The circulating hot water outlet of the medium- and high-temperature heat pump 21 is connected to the pipeline between the circulating hot water outlet of the top condensing heat recovery device 25 and the circulating hot water inlet of the ultra-high temperature heat pump 3 through a pipeline, and the circulating hot water inlet of the medium- and high-temperature heat pump 21 is connected to the pipeline between the circulating hot water outlet of the ultra-high temperature heat pump 3 and the circulating hot water inlet of the top condensing heat recovery device 25 through a pipeline.

[0046] The absorption tower 28 has an ammonia vapor inlet at the bottom, an ammonia water outlet at the bottom, an ammonia water inlet in the middle, and a non-condensable gas outlet at the top.

[0047] The two-phase fluid outlet of the top condensing heat recovery device 25 is connected to the two-phase fluid inlet of the reflux tank 26, the reflux port of the reflux tank 26 is connected to the inlet of the reflux pump 29, the outlet of the reflux pump 29 is connected to the reflux liquid inlet of the flash steam stripping tower 13, the ammonia vapor outlet of the reflux tank 26 is connected to the ammonia vapor inlet of the absorption tower 28, the ammonia water outlet of the absorption tower 28 is connected to the inlet of the ammonia water pump 210, the outlet of the ammonia water pump 210 is connected to the ammonia water inlet of the medium and low temperature heat pump 27, the ammonia water outlet of the medium and low temperature heat pump 27 is connected to the first interface of the second tee 211, and the second interface of the second tee 211 is connected to the concentrated ammonia tank 212.

[0048] In some embodiments, the two-phase fluid outlet of the top condensing heat recovery device is connected to the two-phase fluid inlet of the reflux tank via a first connecting pipe. The reflux port of the reflux tank is connected to the inlet of the reflux pump via a second connecting pipe. The outlet of the reflux pump is connected to the reflux liquid inlet of the flash steam stripping tower via a third connecting pipe. The ammonia vapor outlet of the reflux tank is connected to the ammonia vapor inlet of the absorption tower via a fourth connecting pipe. The ammonia water outlet of the absorption tower is connected to the inlet of the ammonia water pump via a fifth connecting pipe. The outlet of the ammonia water pump is connected to the ammonia water inlet of the medium and low temperature heat pump via a sixth connecting pipe.

[0049] During use, during the ammonia nitrogen wastewater stripping process, the mixed vapor containing ammonia, water vapor, non-condensable gas, etc. drawn out from the vapor outlet of the flash steam stripping tower 13 enters the tower top condensation heat recovery device 25 through a pipeline and is cooled by the circulating hot water flowing through the tower top condensation heat recovery device 25. The water vapor condenses into liquid water during the cooling process, thereby making the mixed vapor a gas-liquid two-phase flow. The resulting gas-liquid two-phase flow enters the reflux tank 26 from the bottom of the tower top condensation heat recovery device 25 through a pipeline to separate ammonia vapor, non-condensable gas and liquid water. The separated liquid aqueous solution containing a small amount of liquid ammonia then enters the flash steam stripping tower 13 through the reflux pump 29 to maintain the temperature in the tower constant and further condense the water vapor in the mixed vapor to increase the ammonia concentration in the mixed vapor at the tower top outlet. The ammonia vapor and non-condensable gas separated in the reflux tank 26 enter the absorption tower 28.

[0050] The concentrated ammonia water at the bottom of the absorption tower 28 enters the medium-low temperature heat pump 27 through the ammonia water pump 210 to release the heat of the ammonia water, and heats the circulating water entering the medium-low temperature heat pump 27. The heated circulating water enters the wastewater preheater 11 and transfers the heat to the high-concentration ammonia nitrogen wastewater entering the wastewater preheater 11.

[0051] After the heat is released by the medium and low temperature heat pump 27, the ammonia water is divided into two paths through the second three-way valve 211. One path enters the concentrated ammonia tank 212 for storage, and the other path enters the absorption tower 28 to spray and absorb the ammonia vapor entering the absorption tower 28 to become concentrated ammonia water. The non-condensable gas mixed in the ammonia vapor is discharged to the atmosphere through the non-condensable gas outlet at the top of the absorption tower 28.

[0052] The circulating hot water in the medium and high temperature heat pump 21 that absorbs the waste heat of the low-concentration ammonia nitrogen wastewater is mixed with the circulating hot water from the top condensing heat recovery device 25 that absorbs the condensation heat of the water vapor in the mixed steam and then enters the ultra-high temperature heat pump 3 at about 50~100℃, so that the heat of the circulating hot water is transferred to the low-concentration ammonia nitrogen wastewater entering the ultra-high temperature heat pump 3 in the ultra-high temperature heat pump 3, so that the low-concentration ammonia nitrogen wastewater entering the ultra-high temperature heat pump 3 is heated to 110-120℃. After the temperature is raised, the low-concentration ultra-high temperature ammonia nitrogen wastewater flashes out low-pressure steam due to the reduction in pressure after entering the flash steam stripping tower 13, thereby stripping the high-concentration ammonia nitrogen wastewater. The circulating hot water that releases heat in the ultra-high temperature heat pump 3 is divided into two paths, and enters the medium and high temperature heat pump 21 and the top condensing heat recovery device 25 for recycling respectively.

[0053] It should be noted that for factories equipped with kilns or boilers, the circulating hot water can be heated by recovering the waste heat from the kiln or boiler flue gas. The heated circulating hot water can also enter the ultra-high temperature heat pump 3 to transfer the heat of the circulating hot water into the low-concentration ammonia nitrogen wastewater in the ultra-high temperature heat pump 3.

[0054] In summary, the beneficial effects of the technical solution of the utility model are as follows: the condensation heat of the overhead steam, the heat of the ammonia water in the absorption tower, the heat of the wastewater discharged after the stripping process, and the waste heat of the factory kiln or boiler flue gas are fully recovered in the traditional ammonia nitrogen wastewater stripping process. The heat of the circulating hot water is then transferred to the low-concentration ammonia nitrogen wastewater discharged from the bottom of the flash steam stripping tower via an ultra-high temperature heat pump to heat it. The heated low-concentration ultra-high temperature ammonia nitrogen wastewater is then passed through the bottom of the flash steam stripping tower to flash the steam out of the high-concentration ammonia nitrogen wastewater to strip ammonia. This system eliminates or reduces the use of external steam for stripping ammonia nitrogen wastewater, and eliminates the need for a refrigeration unit and circulating cooling tower for cooling, thereby saving the operating costs of the stripping and ammonia evaporation process.

[0055] The specific embodiments of the present invention described above do not limit the scope of protection of the present invention. Any other corresponding changes and modifications made based on the technical concept of the present invention should be included in the scope of protection of the claims of the present invention.

Claims

1. A waste heat full recovery type ammonia nitrogen wastewater flash steam stripping system, characterized in that: include: a stripping device comprising a flash stripping tower; A waste heat recovery device, which is used to recover the condensation heat of the top steam of the flash steam stripping tower, the heat of the ammonia water in the tower, the heat of the discharged waste water, and the waste heat of the flue gas from the kiln or boiler in the factory area; and The ultra-high temperature heat pump is used to transfer the recovered heat to the low-concentration ammonia nitrogen wastewater discharged from the bottom of the flash steam stripping tower to heat it up. The heated low-concentration ultra-high temperature ammonia nitrogen wastewater is passed into the bottom of the flash steam stripping tower to flash out steam to strip the high-concentration ammonia nitrogen wastewater and evaporate ammonia.

2. The waste heat full recovery type ammonia nitrogen wastewater flash stripping system according to claim 1, characterized in that: The stripping device also includes a wastewater preheater, a wastewater reheater, a high-concentration ammonia nitrogen wastewater tank and a feed pump. One side of the wastewater preheater is the inlet and outlet of high-concentration ammonia nitrogen wastewater, and the other side is the inlet and outlet of circulating hot water. One side of the wastewater reheater is the inlet and outlet of high-concentration ammonia nitrogen wastewater, and the other side is the inlet and outlet of low-concentration ammonia nitrogen wastewater. The flash steam stripping tower includes an ammonia nitrogen wastewater inlet at the middle and upper part, an ammonia nitrogen wastewater outlet at the bottom of the tower, an ultra-high temperature wastewater inlet at the bottom, a steam outlet at the top of the tower, and a reflux liquid inlet at the top.

3. The waste heat full recovery type ammonia nitrogen wastewater flash stripping system according to claim 2, characterized in that: The high-concentration ammonia nitrogen wastewater tank is connected to the inlet of the feed pump, the outlet of the feed pump is connected to the high-concentration ammonia nitrogen wastewater inlet of the wastewater preheater, the high-concentration ammonia nitrogen wastewater outlet of the wastewater preheater is connected to the high-concentration ammonia nitrogen wastewater inlet of the wastewater reheater, and the high-concentration ammonia nitrogen wastewater outlet of the wastewater reheater is connected to the ammonia nitrogen wastewater inlet of the flash steam stripping tower.

4. The waste heat full recovery type ammonia nitrogen wastewater flash stripping system according to claim 3, characterized in that: The waste heat recovery device includes a medium- and high-temperature heat pump, a forced circulation pump at the bottom of the tower, a first three-way connection, a wastewater treatment tank, a condensation heat recovery device at the top of the tower, a reflux tank, a medium- and low-temperature heat pump, an absorption tower, a reflux pump, an ammonia pump, a second three-way connection and a concentrated ammonia tank; One side of the medium and high temperature heat pump is for the inlet and outlet of low concentration ammonia nitrogen wastewater, and the other side is for the inlet and outlet of circulating hot water; The ammonia nitrogen wastewater outlet of the flash steam stripping tower is connected to the inlet of the tower bottom forced circulation pump, the outlet of the tower bottom forced circulation pump is connected to the first interface of the first tee, the second interface of the first tee is connected to the low-concentration ammonia nitrogen wastewater inlet of the wastewater reheater, the low-concentration ammonia nitrogen wastewater outlet of the wastewater reheater is connected to the ammonia nitrogen wastewater inlet of the medium and high temperature heat pump, the ammonia nitrogen wastewater outlet of the medium and high temperature heat pump is connected to the wastewater treatment tank, the third interface of the first tee is connected to the ammonia nitrogen wastewater inlet of the ultra-high temperature heat pump, and the ammonia nitrogen wastewater outlet of the ultra-high temperature heat pump is connected to the ultra-high temperature wastewater inlet of the flash steam stripping tower; The tower top condensation heat recovery device has a steam inlet, a circulating hot water inlet and outlet, and a two-phase fluid outlet. The steam outlet of the flash steam stripping tower is connected to the steam inlet of the tower top condensation heat recovery device, and the circulating hot water inlet and circulating hot water outlet of the tower top condensation heat recovery device are respectively connected to the circulating hot water outlet and circulating hot water inlet of the ultra-high temperature heat pump; The reflux tank has a two-phase fluid inlet, a reflux port, and an ammonia vapor outlet. One side of the medium and low temperature heat pump is an ammonia inlet and outlet, and the other side is a circulating water inlet and outlet. The circulating water inlet and the circulating water outlet of the medium and low temperature heat pump are respectively connected to the circulating water inlet and outlet of the wastewater preheater. The circulating hot water outlet of the medium and high temperature heat pump is connected to the pipeline between the circulating hot water outlet of the tower top condensing heat recovery device and the circulating hot water inlet of the ultra-high temperature heat pump through a pipeline. The circulating hot water inlet of the medium and high temperature heat pump is connected to the pipeline between the circulating hot water outlet of the ultra-high temperature heat pump and the circulating hot water inlet of the tower top condensing heat recovery device through a pipeline. The absorption tower has an ammonia vapor inlet at the bottom, an ammonia water outlet at the bottom, an ammonia water inlet in the middle, and a non-condensable gas outlet at the top; The two-phase fluid outlet of the tower top condensation heat recovery device is connected to the two-phase fluid inlet of the reflux tank, the reflux port of the reflux tank is connected to the inlet of the reflux pump, the outlet of the reflux pump is connected to the reflux liquid inlet of the flash steam stripping tower, and the ammonia vapor outlet of the reflux tank is connected to the ammonia vapor inlet of the absorption tower; The ammonia outlet of the absorption tower is connected to the inlet of the ammonia pump, and the outlet of the ammonia pump is connected to the ammonia inlet of the medium and low temperature heat pump; The ammonia outlet of the medium- and low-temperature heat pump is communicated with the first interface of the second tee, and the second interface of the second tee is communicated with the concentrated ammonia tank.

5. The waste heat full recovery type ammonia nitrogen wastewater flash stripping system according to claim 4, characterized in that: The two-phase fluid outlet of the tower top condensation heat recovery device is communicated with the two-phase fluid inlet of the reflux tank via a first connecting pipe.

6. The waste heat full recovery type ammonia nitrogen wastewater flash stripping system according to claim 4, characterized in that: The reflux port of the reflux tank is communicated with the inlet of the reflux pump via a second connecting pipe.

7. The waste heat full recovery type ammonia nitrogen wastewater flash stripping system according to claim 4, characterized in that: The outlet of the reflux pump is communicated with the reflux liquid inlet of the flash steam stripping tower via a third connecting pipe.

8. The waste heat full recovery type ammonia nitrogen wastewater flash stripping system according to claim 4, characterized in that: The ammonia vapor outlet of the reflux tank is connected to the ammonia vapor inlet of the absorption tower via a fourth connecting pipe.

9. The waste heat full recovery type ammonia nitrogen wastewater flash stripping system according to claim 4, characterized in that: The ammonia water outlet of the absorption tower is connected to the inlet of the ammonia water pump via a fifth connecting pipe.

10. The waste heat full recovery type ammonia nitrogen wastewater flash stripping system according to claim 4, characterized in that: The outlet of the ammonia water pump is connected to the ammonia water inlet of the medium- and low-temperature heat pump via a sixth connecting pipe.

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