CN115196807A - Treatment method for deacidifying and deaminating coal chemical wastewater with enhanced waste heat recovery - Google Patents
Treatment method for deacidifying and deaminating coal chemical wastewater with enhanced waste heat recovery Download PDFInfo
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- CN115196807A CN115196807A CN202210873417.3A CN202210873417A CN115196807A CN 115196807 A CN115196807 A CN 115196807A CN 202210873417 A CN202210873417 A CN 202210873417A CN 115196807 A CN115196807 A CN 115196807A
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- 239000002351 wastewater Substances 0.000 title claims abstract description 58
- 238000000034 method Methods 0.000 title claims abstract description 39
- 239000003245 coal Substances 0.000 title claims abstract description 30
- 239000000126 substance Substances 0.000 title claims abstract description 28
- 239000002918 waste heat Substances 0.000 title claims abstract description 26
- 238000011084 recovery Methods 0.000 title claims abstract description 16
- 238000006481 deamination reaction Methods 0.000 claims abstract description 47
- 230000009615 deamination Effects 0.000 claims abstract description 46
- 238000001704 evaporation Methods 0.000 claims abstract description 30
- 230000008020 evaporation Effects 0.000 claims abstract description 30
- 239000007788 liquid Substances 0.000 claims abstract description 29
- 239000007789 gas Substances 0.000 claims abstract description 28
- 239000002253 acid Substances 0.000 claims abstract description 21
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 claims abstract description 19
- VHUUQVKOLVNVRT-UHFFFAOYSA-N Ammonium hydroxide Chemical compound [NH4+].[OH-] VHUUQVKOLVNVRT-UHFFFAOYSA-N 0.000 claims abstract description 18
- XKMRRTOUMJRJIA-UHFFFAOYSA-N ammonia nh3 Chemical compound N.N XKMRRTOUMJRJIA-UHFFFAOYSA-N 0.000 claims abstract description 18
- 235000011114 ammonium hydroxide Nutrition 0.000 claims abstract description 18
- 229910021529 ammonia Inorganic materials 0.000 claims abstract description 9
- 230000002708 enhancing effect Effects 0.000 claims abstract description 8
- 239000010865 sewage Substances 0.000 claims abstract description 7
- 238000005204 segregation Methods 0.000 claims abstract description 3
- 239000000463 material Substances 0.000 claims description 19
- 239000007791 liquid phase Substances 0.000 claims description 15
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 15
- 239000003513 alkali Substances 0.000 claims description 8
- 239000012071 phase Substances 0.000 claims description 8
- 238000010438 heat treatment Methods 0.000 claims description 7
- 238000000605 extraction Methods 0.000 claims description 6
- 230000010354 integration Effects 0.000 claims description 5
- 238000007872 degassing Methods 0.000 claims description 4
- 238000000746 purification Methods 0.000 claims description 4
- 238000010992 reflux Methods 0.000 claims description 4
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 claims description 3
- 238000009833 condensation Methods 0.000 claims description 3
- 230000005494 condensation Effects 0.000 claims description 3
- 238000012545 processing Methods 0.000 claims description 3
- 229910052717 sulfur Inorganic materials 0.000 claims description 3
- 239000011593 sulfur Substances 0.000 claims description 3
- 238000012546 transfer Methods 0.000 claims description 3
- 239000008346 aqueous phase Substances 0.000 claims 1
- 239000000428 dust Substances 0.000 claims 1
- 239000007921 spray Substances 0.000 claims 1
- 230000008569 process Effects 0.000 abstract description 18
- 238000004065 wastewater treatment Methods 0.000 description 5
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- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F9/00—Multistage treatment of water, waste water or sewage
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- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F1/00—Treatment of water, waste water, or sewage
- C02F1/02—Treatment of water, waste water, or sewage by heating
- C02F1/04—Treatment of water, waste water, or sewage by heating by distillation or evaporation
- C02F1/041—Treatment of water, waste water, or sewage by heating by distillation or evaporation by means of vapour compression
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- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F1/00—Treatment of water, waste water, or sewage
- C02F1/02—Treatment of water, waste water, or sewage by heating
- C02F1/04—Treatment of water, waste water, or sewage by heating by distillation or evaporation
- C02F1/06—Flash evaporation
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- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F1/00—Treatment of water, waste water, or sewage
- C02F1/26—Treatment of water, waste water, or sewage by extraction
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- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F1/00—Treatment of water, waste water, or sewage
- C02F1/40—Devices for separating or removing fatty or oily substances or similar floating material
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- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F2101/00—Nature of the contaminant
- C02F2101/10—Inorganic compounds
- C02F2101/16—Nitrogen compounds, e.g. ammonia
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- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F2103/00—Nature of the water, waste water, sewage or sludge to be treated
- C02F2103/34—Nature of the water, waste water, sewage or sludge to be treated from industrial activities not provided for in groups C02F2103/12 - C02F2103/32
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
- Y02B30/00—Energy efficient heating, ventilation or air conditioning [HVAC]
- Y02B30/52—Heat recovery pumps, i.e. heat pump based systems or units able to transfer the thermal energy from one area of the premises or part of the facilities to a different one, improving the overall efficiency
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Abstract
The invention belongs to the technical field of sewage treatment, and discloses a treatment method for deacidifying and deaminating coal chemical wastewater for enhancing waste heat recovery. Removing part of acid gas and ammonia nitrogen from the coal chemical wastewater through negative pressure flash evaporation, recovering energy in a flash evaporation steam mode, reducing the temperature of a wastewater system, increasing the temperature level and pressure grade of outlet flash evaporation steam through a heat pump device, and sending the outlet flash evaporation steam into a deacidification, deamination and pressurization stripping tower; after the outlet wastewater is treated by a deoiling and dedusting working section, acid gas and ammonia nitrogen are separated in a pressure stripping tower, the temperature level and the pressure grade of ammonia water vapor at the lateral line are improved by a heat pump to heat kettle liquid of the pressure stripping tower and heat feeding of a preheating stripping tower, then the ammonia water vapor is sent into a three-stage segregation device to purify ammonia, the kettle liquid of the pressure stripping tower is subjected to heat exchange with the heat feeding, is sent to a negative pressure flash evaporation to reduce the temperature and enters an intermediate tank, and the flash evaporation vapor is used for preheating the heat feeding of a deacidification and deamination tower. The method ensures the removal efficiency and effluent index of acid gas and ammonia nitrogen, and improves the economic performance and energy-saving efficiency of the pretreatment process.
Description
Technical Field
The invention belongs to the technical field of sewage treatment, and particularly relates to a treatment method for deacidifying and deaminating coal chemical wastewater for enhancing waste heat recovery.
Background
The modern novel coal chemical industry is an important way for promoting clean and efficient utilization and industrial transformation of coal in China and promoting integrated development of thermoelectric oil gas, wherein a fixed bed gasification technology and a medium-low temperature pyrolysis technology are effective methods for realizing efficient transformation of low-rank coal. The fixed bed gasification wastewater and the low-rank coal pyrolysis wastewater are generated in the processes of crude coal gas cooling and washing, medium-low temperature dry distillation and crude coal gas cooling and washing, are rich in acid gas and ammonia nitrogen, carry a large amount of waste heat at 70-150 ℃, and have high treatment difficulty. Is one of the problems in the pretreatment, quality improvement and efficiency improvement of the coal chemical wastewater.
The wastewater is generally subjected to removal of acid gas and ammonia nitrogen and recovery of high-concentration acid gas and ammonia gas by adopting a chemical separation process at home and abroad. The prior coal chemical industry wastewater deacidification and deamination process mainly comprises single-tower pressurization stripping deacidification and deamination and double-tower pressurization stripping deacidification and deamination, wherein inlet water enters a system from the tower top and the upper section in the tower by cold and hot feeding, and the simultaneous removal of acid gas and ammonia nitrogen is realized by utilizing the relative volatility difference of the acid gas and the ammonia nitrogen under the pressurization condition. However, the operation process of the separation flow consumes a large amount of medium-pressure steam, and the energy utilization efficiency is not high, so that the medium-pressure steam consumption is increased. And the key for promoting the energy saving and consumption reduction of the whole process is to improve the energy utilization efficiency of the whole process.
Under the new trend of the current technical means and the new trend of the national energy agency and the ministry of environmental protection for improving the energy utilization efficiency of the coal chemical industry and the quality and the efficiency of the coal chemical industry wastewater treatment, the insufficient energy utilization efficiency of the whole process not only increases the process public engineering consumption and the operation cost, but also has certain influence on other units. The waste heat loss of the prior coal chemical wastewater pretreatment is shown as follows: the waste water discharged from the waste heat boiler adopts circulating cooling water for heat exchange to ensure that the waste water meets the requirement of the water inlet temperature for deoiling and dedusting, and a large amount of waste heat is taken away by the circulating cooling water; the deacidification deamination unit adopts ammonia water vapor extracted by pressure rectification to exchange heat with hot feed and then sends the ammonia water vapor to a three-stage fractional condensation device for treatment, wherein the gas phase contains a large amount of waste heat to preheat the hot feed of wastewater, and the residual heat is taken away by circulating water; the defects of the energy integration system increase the public engineering consumption in the wastewater treatment process, bring adverse effects to front-end de-oiling and dedusting, realize energy conservation and consumption reduction of the wastewater pretreatment process, and are the actual difficulties and challenges faced by coal chemical wastewater in new situation.
Disclosure of Invention
Aiming at the defects in the prior art, the invention aims to provide a treatment method for deacidifying and deaminating coal chemical wastewater, which can be used for enhancing waste heat recovery.
A treatment method for deacidifying and deaminating waste water in coal chemical industry for enhancing waste heat recovery comprises the following steps:
(1) Negative pressure flash evaporation degassing: acid gas and ammonia nitrogen in the coal chemical industry wastewater are partially removed through a negative pressure flash evaporation system, so that the absolute pressure of the negative pressure flash evaporation tank is reduced to 5 kPa-10 kPa, the temperature of the effluent is 35-40 ℃, the pressure of an outlet of a vacuum pump is 0.1 MPa-0.3 MPa, energy is recovered in a flash evaporation gas phase mode, and the temperature of a wastewater system is reduced;
(2) Boosting the pressure of the flash steam heat pump: the temperature and pressure grade of the flash steam in the step (1) are increased by a mechanical steam recompression type heat pump device, the pressure of an outlet of the heat pump is increased to 0.45-0.6 MPa and sent into a deacidification, deamination and pressurization stripping tower, and liquid-phase wastewater is sent into a deoiling and dedusting section;
(3) Deoiling and dedusting: the deoiling and dedusting workshop section is connected with the bottom of the flash tank through a vacuum pump and is used for deoiling and dedusting liquid-phase wastewater;
(4) Deacidifying and deaminating in a pressurizing stripping tower: feeding the two materials of the liquid phase wastewater after deoiling and dedusting in the step (3) into a pressurized stripping tower with a side line from the upper part and the middle upper part of the pressurized stripping tower, wherein the pressure at the top of the tower is 0.3-0.65 MPa, the temperature is 40-80 ℃, the pressure at the bottom of the tower is 0.32-0.65 MPa, and the temperature is 140-160 ℃; the vapor pressure of the mixed ammonia water extracted from the side line is 0.3MPa to 0.6MPa, the temperature is 120 ℃ to 150 ℃, and the kettle liquid is extracted from the bottom of the tower and divided into one strand to be used as the tower kettle for reboiling and forced circulation;
(5) Waste heat utilization and integration: sending the mixed ammonia water vapor collected from the side line in the step (4) into a mechanical vapor recompression type heat pump to increase the temperature level and the pressure level for heating the deacidification, deamination and pressurization stripping tower kettle liquid and preheating and pressurization stripping tower hot feed, and then sending the mixed ammonia water vapor into a three-stage dephlegmator for ammonia purification; residual heat of 100-140 ℃ is obtained after heat exchange is carried out on the kettle liquid of the pressurized stripping tower with hot feeding materials, the residual heat is reduced to 50-70 ℃ required by an extraction dephenolization unit after negative pressure flash evaporation, and then the residual heat is sent to an intermediate tank, and flash evaporation steam is used for preheating hot feeding materials of the pressurized stripping tower.
Further, the absolute pressure of the negative pressure flash tank is 5MPa to 30MPa.
Further, the outlet pressure of the mechanical vapor recompression type heat pump is 0.4 MPa-0.8 MPa.
Furthermore, the number of the tower plates of the pressurized stripping tower is 40-60.
The device of the treatment method for deacidifying and deaminating coal chemical wastewater for enhancing waste heat recovery comprises a sewage pump, a vacuum pump a, a vacuum pump b, a negative pressure flash tank a, a negative pressure flash tank b, a mechanical steam recompression type heat pump a, a mechanical steam recompression type heat pump b, a deoiling and dedusting device, a deacidifying and deaminating pressurization stripping tower, alkali liquor, an acid gas treatment device, low-pressure steam, a heat exchanger, a three-stage segregating device and a storage tank, wherein:
the sewage pump is connected to a sprayer at the upper part of the negative pressure flash tank a, and the top of the negative pressure flash tank a is connected with an inlet of a vacuum pump a; the mechanical vapor recompression type heat pump a is connected with the outlet of the vacuum pump a; the deoiling and dedusting device is connected with a liquid phase at the bottom of the negative pressure flash tank a through a pump; the lower section of the deacidification, deamination and pressurization stripping tower is connected with an outlet of a vacuum pump a after the pressure is increased by a mechanical steam recompression type heat pump a, the middle and lower sections of the deacidification, deamination and pressurization stripping tower are connected with alkali liquor, and the top of the deacidification, deamination and pressurization stripping tower is connected with a sulfur recovery device; ammonia water vapor extracted from the tower side line is subjected to pressure boosting through a mechanical vapor recompression type heat pump b, then sequentially flows back through a heat exchanger heating kettle liquid and is subjected to thermal feeding, and an outlet is connected with a three-stage segregation device; pumping the deacidification deamination pressurizing stripping tower kettle liquid, returning the deacidification deamination pressurizing stripping tower kettle as kettle liquid after reflux heat exchange and low-pressure steam reboiling, and sending the deacidification deamination pressurizing stripping tower kettle as deacidification deamination outlet water to a post-system; deacidifying deamination effluent is connected with a sprayer at the upper part of a negative pressure flash tank b after heat exchange with hot feed through a heat exchanger, the top of the negative pressure flash tank b is connected with a vacuum pump b, a condensed water phase generated after heat exchange of an outlet of the vacuum pump b with the hot feed through the heat exchanger is connected to a storage tank in a backflow mode, the bottom of the negative pressure flash tank b is connected with the storage tank through a pump, and deamination effluent in the storage tank is pumped to a post-system for treatment.
Furthermore, the storage tank is a normal pressure container with the temperature of 40-75 ℃.
Still further, the negative pressure flash tank includes, but is not limited to, types of equipment employing a packed tank or a swirl tank.
Still further, the pressurized stripping column includes, but is not limited to, types of equipment employing a tray column, a packed column, or a packed coupled tray column.
Further, the mechanical vapor recompression heat pump and vacuum pump are not limited to the type of equipment that can perform the functions described herein.
Compared with the prior art, the invention has the following advantages:
(1) The invention is developed aiming at the water quality characteristics of each process node of the coal chemical industry wastewater and the industrial operation characteristics of the low-temperature waste heat carried by the process logistics, effectively recovers the low-temperature waste heat of 70-150 ℃ in the process, recycles the low-temperature waste heat to the corresponding hot hydrazine of a wastewater treatment system, recovers the energy in a heat pump mode and directly uses the energy for preheating and reboiling materials in the system, effectively improves the energy utilization efficiency of the whole process, reduces the energy consumption of public works and improves the operation economy of the whole system.
(2) The invention adjusts the temperature level of the material at the outlet of the heat pump through frequency conversion, improves the heating performance coefficient of the heat pump, reduces the power consumption, plays the roles of assisting peak regulation and stabilizing the operation of the system, takes industrial wastewater as a low-temperature heat source, realizes the waste heat absorption in the system in the forms of latent heat and sensible heat through the means of vapor recompression, provides high-quality energy for a multi-point heat trap, comprehensively considers the separation requirement of a pressurized stripping tower and the gas phase composition of a tower plate, reduces the heat loss in the heat transfer process through the form of direct connection of the vapor, and also ensures the effluent index of the wastewater treatment in the process.
(3) According to the invention, the purpose of reducing the temperature of the wastewater is achieved by carrying out negative pressure flash evaporation on the industrial raw water, and meanwhile, part of acid gas and ammonia nitrogen in the wastewater are removed, so that a good environment is created for the deoiling and dedusting unit, and the high-efficiency resource removal of organic matters in the wastewater is facilitated. The whole system reduces the consumption of circulating water while recovering low-temperature waste heat, reduces the consumption of public engineering including circulating cooling water and low-pressure steam by more than 72 percent, and indirectly improves the economic performance, the energy-saving efficiency and the environmental benefit of the pretreatment process.
Drawings
FIG. 1 is a simplified diagram of the deacidification and deamination treatment process of waste water from coal chemical industry with enhanced waste heat recovery according to the present invention.
The figure includes: the method comprises the following steps of 1-deacidifying, deaminating and pressurizing stripping tower, 2, 4-negative pressure flash tank a and negative pressure flash tank b, 3-deoiling and dedusting device, 5-storage tank, 6-three-stage dephlegmation device, 7-acid gas treatment device, 8, 9-vacuum pump a and vacuum pump b,10, 11-mechanical steam recompression type heat pump a and mechanical steam recompression type heat pump b, 12-low pressure steam, 13-deamination effluent and 14-alkali liquor.
Detailed Description
Those skilled in the art will appreciate that the invention may be practiced without these specific details. Although illustrative embodiments of the present invention have been described above to facilitate the understanding of the present invention by those skilled in the art, it should be understood that the present invention is not limited to the scope of the embodiments, and various changes may be made apparent to those skilled in the art as long as they are within the spirit and scope of the present invention as defined and defined by the appended claims, and all matters of the invention which utilize the inventive concepts are protected.
As shown in fig. 1, raw material wastewater is connected to a sprayer at the upper part of a negative pressure flash tank a 2 through a sewage pump, the top of the negative pressure flash tank a 2 is connected with an inlet of a vacuum pump a 8, an outlet of the vacuum pump a 8 is connected with the lower section of a deacidification, deamination and pressurization stripping tower 1 after being pressurized by a mechanical steam recompression type heat pump a 10, a liquid phase at the bottom of the negative pressure flash tank a 2 is connected with a deoiling and dedusting device 3 through a pump, treated effluent is divided into two materials through a pump, one material is sent to the upper section of the deacidification, deamination and pressurization stripping tower 1 as a cold feed, the other material is sent to the upper section of the deacidification, deamination and pressurization stripping tower 1 as a hot feed after being subjected to heat exchange in sequence through a heat exchanger, an alkali liquor 14 is connected with the middle and lower section of the deacidification, deamination and pressurization stripping tower 1 to convert fixed ammonia in water, an acid gas at the top is sent to a sulfur recovery device 7 under self-pressure, ammonia water vapor extracted from a tower side line is pressurized through a mechanical steam recompression type heat pump b 11 and then is heated to reflux and hot feed through the heat exchanger in sequence, and an outlet is connected with a three-stage dephlegmation device 6;
the pressure of the kettle liquid of the deacidification, deamination and pressurization stripping tower 1 is boosted by a pump, one part of the kettle liquid is used as the kettle liquid to flow back, heat exchange is carried out, the low-pressure steam 12 is boiled again, the kettle liquid is returned to the tower kettle of the deacidification, deamination and pressurization stripping tower 1, and the other part of the kettle liquid is used as the effluent water of the deacidification, deamination and pressurization stripping tower and is sent to a post-system; deacidifying deamination effluent is connected with a sprayer at the upper part of a negative pressure flash tank b 4 after heat exchange with hot feed through a heat exchanger, the top of the negative pressure flash tank b 4 is connected with a vacuum pump b 9, the outlet of the vacuum pump b 9 is connected with a storage tank 5 through condensed water phase generated after heat exchange with the hot feed through the heat exchanger in a backflow mode, the bottom of the negative pressure flash tank b 4 is connected with the storage tank 5 through a pump, and deamination effluent 13 of the storage tank 5 is pumped to a post-system for treatment.
Example 1
The flow rate is 130m 3 The method comprises the following steps of treating the wastewater to be treated with the sulfide content of 3200mg/L, the ammonia nitrogen content of 5000mg/L, the pH value of 9.7 and the water temperature of 80 ℃ according to the method of the invention:
(1) Negative pressure flash evaporation degassing: acid gas and ammonia nitrogen in the coal chemical industry wastewater are partially removed through a negative pressure flash evaporation system, so that the absolute pressure of the negative pressure flash evaporation tank is reduced from 20kPa to 8kPa, the effluent temperature is 38 ℃, the outlet pressure of a vacuum pump is 0.2MPa, the temperature is 105 ℃, energy is recovered in a flash evaporation gas phase mode, and the temperature of a wastewater system is reduced;
(2) Boosting the pressure of the flash steam heat pump: the temperature and the pressure grade of the flash steam in the step (1) are increased by a mechanical steam recompression type heat pump device, so that the pressure of an outlet of the heat pump is increased to 0.50MPa and the temperature is 172 ℃, the flash steam is sent to a deacidification, deamination and pressurization stripping tower, and liquid-phase wastewater is sent to a deoiling and dedusting section;
(3) Deoiling and dedusting: the deoiling and dedusting workshop section is connected with the bottom of the flash tank through a vacuum pump and is used for deoiling and dedusting liquid-phase wastewater;
(4) Deacidifying and deaminating in a pressurizing stripping tower: feeding the two materials of the liquid-phase wastewater subjected to deoiling and dedusting in the step (3) into a pressurized stripping tower with a side line from the upper part and the middle upper part of the pressurized stripping tower, wherein the number of tower plates of the pressurized stripping tower is 54, the cold feeding position is the 1 st plate, the hot feeding position is the 10 th plate, the side line extraction position is the 24 th plate, the alkali liquor feeding position is the 30 th plate, the flash steam feeding position is the 39 th plate, the tower top pressure is 0.40MPa, the tower top temperature is 55 ℃, the tower bottom pressure is 0.42MPa, and the tower bottom temperature is 146 ℃; the vapor pressure of mixed ammonia water extracted from the side line is 0.43MPa, the temperature is 137 ℃, and kettle liquid is extracted from the bottom of the tower and is divided into one strand to be used as a tower kettle for reboiling and forced circulation;
(5) Waste heat utilization integration: sending the mixed ammonia water vapor collected from the side line in the step (4) into a mechanical vapor recompression type heat pump to increase the temperature level and the pressure level for heating the deacidification, deamination and pressurization stripping tower kettle liquid and preheating and pressurization stripping tower hot feed, and then sending the mixed ammonia water vapor into a three-stage dephlegmator for ammonia purification; the outlet pressure of the heat pump is increased to 0.56MPa, the temperature is 221 ℃, the temperature is 150 ℃ after the heat exchange with the kettle liquid in a backflow mode, the temperature is 131 ℃ after the heat exchange with the hot feeding, the temperature of the kettle liquid of the deacidification, deamination and pressurization stripping tower is 128 ℃ after the heat exchange with the hot feeding, the temperature is reduced to 60 ℃ required by the extraction dephenolization unit after the negative pressure flash evaporation, the temperature is sent to an intermediate tank, the flash evaporation steam is used for preheating the hot feeding of the pressurization stripping tower, and the temperature of the hot feeding into the pressurization stripping tower is 125 ℃.
The processing result and the energy-saving effect are as follows: after the ammonia is deacidified, the acid gas content of the wastewater is less than 50mg/L, the ammonia nitrogen content is less than 120mg/L, the consumption of a hot public work is reduced by 78%, the consumption of a cold public work is reduced by 72%, the removal efficiency of the acid gas and the ammonia nitrogen in the wastewater is guaranteed, the obvious energy-saving effect is achieved, a new energy-saving technology is provided for removing the characteristic pollutants such as the acid gas, the ammonia nitrogen and the like from the wastewater in the coal chemical industry with high efficiency and low consumption, and a foundation is laid for the development of energy conservation and emission reduction in the wastewater treatment industry.
Example 2
The flow rate is 40m 3 The coal chemical industry wastewater to be treated with the sulfide content of about 4000mg/L, the ammonia nitrogen content of about 6500mg/L, the pH value of 10.0 and the water temperature of 75 ℃ is treated according to the method of the invention by adopting the following steps:
(1) Negative pressure flash evaporation degassing: acid gas and ammonia nitrogen in the coal chemical industry wastewater to be treated are partially removed through a negative pressure flash evaporation system, so that the absolute pressure of the negative pressure flash evaporation tank is reduced from 25kPa to 7kPa, the effluent temperature is 37 ℃, the outlet pressure of a vacuum pump is 0.15MPa, the temperature is 104 ℃, energy is recovered in a flash evaporation gas phase mode, and the temperature of a wastewater system is reduced;
(2) Boosting the pressure of the flash steam heat pump: the temperature level and the pressure grade of the flash steam in the step (1) are increased by a mechanical steam recompression type heat pump device, so that the pressure of an outlet of the heat pump is increased to 0.60MPa and the temperature is 194 ℃, the flash steam is sent to a deacidification, deamination and pressurization stripping tower, and liquid-phase wastewater is sent to a deoiling and dedusting section;
(3) Deoiling and dedusting: the deoiling and dedusting workshop section is connected with the bottom of the flash tank through a vacuum pump and is used for deoiling and dedusting liquid-phase wastewater;
(4) Pressure stripping tower deacidification deamination: feeding the two materials of the liquid phase wastewater subjected to deoiling and dedusting in the step (3) into a pressurized stripping tower with a side line from the upper part and the middle upper part of the pressurized stripping tower, wherein the number of tower plates of the pressurized stripping tower is 57, the cold feeding position is the 1 st plate, the hot feeding position is the 11 th plate, the side line extraction position is the 27 th plate, the alkali liquor feeding position is the 32 th plate, the flash steam feeding position is the 40 th plate, the tower top pressure is 0.50MPa, the tower top temperature is 52 ℃, the tower bottom pressure is 0.52MPa, the temperature is 157 ℃, the mixed ammonia steam pressure extracted from the side line is 0.53MPa, the temperature is 146 ℃, the tower bottom is extracted with kettle liquid and is divided into two materials to be used as a tower kettle reboiled forced circulation;
(5) Waste heat utilization integration: sending the mixed ammonia water vapor collected from the side line in the step (4) into a mechanical vapor recompression type heat pump to increase the temperature level and the pressure level for heating the deacidification, deamination and pressurization stripping tower kettle liquid and preheating and pressurization stripping tower hot feed, and then sending the mixed ammonia water vapor into a three-stage dephlegmator for ammonia purification; the outlet pressure of the heat pump is increased to 0.62MPa, the temperature is 243 ℃, the temperature is 170 ℃ after the heat exchange with the kettle liquid by backflow, the temperature is 132 ℃ after the heat exchange with the hot feeding material, the temperature is reduced to 65 ℃ required by the extraction dephenolization unit after the negative pressure flash evaporation, the hot feeding material is sent into an intermediate tank, the flash evaporation steam is used for preheating the hot feeding material of the pressurization stripping tower, and the temperature of the hot feeding material is 130 ℃ after the hot feeding material is fed into the pressurization stripping tower.
The processing result and the energy-saving effect are as follows: after the ammonia is deacidified, the acid gas content of the wastewater is less than 50mg/L, the ammonia nitrogen content is less than 150mg/L, the consumption of thermal public works is reduced by 81%, the consumption of cold public works is reduced by 74%, and the energy-saving operation of wastewater deacidification and deamination is realized.
Finally, it should be noted that: the above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; although modifications or equivalent substitutions may be made in the technical solutions or parts of the technical features set forth in the foregoing embodiments, these modifications or substitutions do not make the essence of the corresponding technical solutions depart from the spirit and scope of the method of the present invention.
Claims (9)
1. A treatment method for deacidifying and deaminating waste water in coal chemical industry for enhancing waste heat recovery is characterized by comprising the following steps: the method comprises the following steps:
(1) Negative pressure flash evaporation degassing: acid gas and ammonia nitrogen in the coal chemical industry wastewater are partially removed through a negative pressure flash evaporation system, so that the absolute pressure of a negative pressure flash evaporation tank is reduced to 5 kPa-10 kPa, the effluent temperature is 35 ℃ to 40 ℃, the outlet pressure of a vacuum pump is 0.1MPa to 0.3MPa, and energy is recovered in a flash evaporation gas phase mode to reduce the temperature of a wastewater system;
(2) Boosting the pressure of the flash steam heat pump: the temperature and pressure grade of the flash steam in the step (1) are increased by a mechanical steam recompression type heat pump device, the pressure of an outlet of the heat pump is increased to 0.45-0.6 MPa and sent into a deacidification, deamination and pressurization stripping tower, and liquid-phase wastewater is sent into a deoiling and dedusting section;
(3) Deoiling and dedusting: the deoiling and dedusting workshop section is connected with the bottom of the flash tank through a vacuum pump and is used for deoiling and dedusting liquid-phase wastewater;
(4) Pressure stripping tower deacidification deamination: feeding the two materials of the liquid phase wastewater after deoiling and dedusting in the step (3) into a pressurized stripping tower with a side line from the upper part and the middle upper part of the pressurized stripping tower, wherein the pressure at the top of the tower is 0.3-0.65 MPa, the temperature is 40-80 ℃, and the pressure at the bottom of the tower is 0.32-0.65 MPa; the vapor pressure of the mixed ammonia water extracted from the side line is 0.3MPa to 0.6MPa, the temperature is 120 ℃ to 150 ℃, and the kettle liquid is extracted from the bottom of the tower and divided into one strand to be used as the tower kettle for reboiling and forced circulation;
(5) Waste heat utilization integration: sending the mixed ammonia water vapor collected from the side line in the step (4) into a mechanical vapor recompression type heat pump to increase the temperature level and the pressure level for heating the deacidification, deamination and pressurization stripping tower kettle liquid and preheating and pressurization stripping tower hot feed, and then sending the mixed ammonia water vapor into a three-stage dephlegmator for ammonia purification; residual heat of 100-140 ℃ is obtained after heat exchange is carried out on the kettle liquid of the pressurized stripping tower and the hot feeding material, the residual heat is reduced to 50-70 ℃ required by an extraction dephenolization unit after negative pressure flash evaporation, the residual heat is sent into an intermediate tank, and flash steam is used for preheating the hot feeding material of the pressurized stripping tower.
2. The treatment method for deacidifying and deaminating coal chemical wastewater for enhancing waste heat recovery according to claim 1, characterized by comprising the following steps: the absolute pressure of the negative pressure flash tank is 5MPa to 30MPa.
3. The treatment method for deacidifying and deaminating coal chemical wastewater with enhanced waste heat recovery according to claim 1, wherein the treatment method comprises the following steps: the outlet pressure of the mechanical vapor recompression type heat pump is 0.4 MPa-0.8 MPa.
4. The treatment method for deacidifying and deaminating coal chemical wastewater for enhancing waste heat recovery according to claim 1, characterized by comprising the following steps: the tower plate number of the pressurized stripping tower is 40-60.
5. An apparatus for implementing the method of claims 1-4, wherein: including sewage pump, vacuum pump a (8) and vacuum pump b (9), negative pressure flash tank a (2) and negative pressure flash tank b (4), mechanical steam recompression formula heat pump a (10) and mechanical steam recompression formula heat pump b (11), deoiling dust collector (3), deacidification deamination pressurization stripping tower (1), alkali lye (14), acid gas processing apparatus (7), low pressure steam (12), heat exchanger, tertiary fractional condensation device and storage tank (5), wherein:
the sewage pump is connected to a sprayer at the upper part of the negative pressure flash tank a (2), and the top of the negative pressure flash tank a (2) is connected with an inlet of a vacuum pump a (8); the mechanical vapor recompression type heat pump a (10) is connected with the outlet of the vacuum pump a (8); the deoiling and dedusting device (3) is connected with a liquid phase at the bottom of the negative pressure flash tank a (2) through a pump; the lower section of the deacidification, deamination and pressurization stripping tower (1) is connected with an outlet of a vacuum pump a (8) after the pressure is increased by a mechanical steam recompression type heat pump a (10), the middle and lower sections of the deacidification, deamination and pressurization stripping tower (1) are connected with alkali liquor (14), and the top of the deacidification, deamination and pressurization stripping tower is connected with a sulfur recovery device (7); ammonia water vapor extracted from the tower side line is subjected to pressure rise through a mechanical vapor recompression type heat pump b (11), then is sequentially subjected to heating kettle liquid reflux and thermal feeding through a heat exchanger, and an outlet is connected with a three-stage segregation device (6); the pressure of the kettle liquid of the deacidification, deamination and pressurization stripping tower (1) is boosted by a pump, one part of the kettle liquid is used as kettle liquid to reflux, heat exchange is carried out, low-pressure steam (12) is boiled again, and then the kettle liquid is returned to the tower kettle of the deacidification, deamination and pressurization stripping tower (1), and the other part of the kettle liquid is used as deacidification, deamination and effluent to be sent to a post-system; deacidifying deamination goes out water and is connected negative pressure flash tank b (4) upper portion spray thrower after heat exchanger and hot feeding heat transfer, and vacuum pump b (9) is connected at negative pressure flash tank b (4) top, and the condensation aqueous phase backward flow that produces after vacuum pump b (9) export carries out the heat transfer through heat exchanger and hot feeding is connected to storage tank (5), and storage tank (5) deamination goes out water (13) and is handled to the back system through the pump to storage tank (5) bottom through pump connection storage tank (5).
6. The apparatus of claim 5, wherein: the storage tank is a normal pressure container with the temperature of 40-75 ℃.
7. The apparatus of claim 5, wherein: the negative pressure flash tank includes, but is not limited to, equipment types employing a packed tank or a cyclone tank.
8. The apparatus of claim 5, wherein: the pressurized stripping column includes, but is not limited to, types of equipment that employ a trayed column, a packed column, or a packed coupled trayed column.
9. The apparatus of claim 5, wherein: the mechanical vapor recompression heat pump and vacuum pump are not limited to the type of equipment capable of performing the functions described herein.
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CN101597124A (en) * | 2009-01-09 | 2009-12-09 | 华南理工大学 | A kind of processing contains the method for phenol ammonia coal gasification waste water |
CN102531260A (en) * | 2011-12-28 | 2012-07-04 | 武汉科梦环境工程有限公司 | Steam stripping technology of high-concentration ammonia nitrogen effluent |
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