CN219964416U - Recovery system for ammonia fixed in condensate of ammonia still - Google Patents
Recovery system for ammonia fixed in condensate of ammonia still Download PDFInfo
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- CN219964416U CN219964416U CN202321376761.8U CN202321376761U CN219964416U CN 219964416 U CN219964416 U CN 219964416U CN 202321376761 U CN202321376761 U CN 202321376761U CN 219964416 U CN219964416 U CN 219964416U
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- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 title claims abstract description 768
- 229910021529 ammonia Inorganic materials 0.000 title claims abstract description 369
- 238000011084 recovery Methods 0.000 title claims abstract description 18
- 239000007788 liquid Substances 0.000 claims abstract description 182
- 238000004821 distillation Methods 0.000 claims abstract description 86
- 239000012452 mother liquor Substances 0.000 claims abstract description 48
- 238000010521 absorption reaction Methods 0.000 claims abstract description 25
- 239000007791 liquid phase Substances 0.000 claims abstract description 24
- 239000002699 waste material Substances 0.000 claims description 18
- 239000012071 phase Substances 0.000 claims description 16
- 238000000354 decomposition reaction Methods 0.000 claims description 8
- 238000010438 heat treatment Methods 0.000 claims description 8
- 239000006096 absorbing agent Substances 0.000 claims 2
- 238000000034 method Methods 0.000 abstract description 14
- CDBYLPFSWZWCQE-UHFFFAOYSA-L Sodium Carbonate Chemical compound [Na+].[Na+].[O-]C([O-])=O CDBYLPFSWZWCQE-UHFFFAOYSA-L 0.000 description 12
- 239000002826 coolant Substances 0.000 description 11
- 150000003839 salts Chemical class 0.000 description 10
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 description 8
- 239000012267 brine Substances 0.000 description 7
- HPALAKNZSZLMCH-UHFFFAOYSA-M sodium;chloride;hydrate Chemical compound O.[Na+].[Cl-] HPALAKNZSZLMCH-UHFFFAOYSA-M 0.000 description 7
- 238000001816 cooling Methods 0.000 description 6
- 238000000926 separation method Methods 0.000 description 6
- 229910000029 sodium carbonate Inorganic materials 0.000 description 6
- 235000017550 sodium carbonate Nutrition 0.000 description 6
- 239000000243 solution Substances 0.000 description 6
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 6
- 239000001569 carbon dioxide Substances 0.000 description 4
- 229910002092 carbon dioxide Inorganic materials 0.000 description 4
- 239000008267 milk Substances 0.000 description 4
- 210000004080 milk Anatomy 0.000 description 4
- 235000013336 milk Nutrition 0.000 description 4
- 235000008733 Citrus aurantifolia Nutrition 0.000 description 3
- 235000011941 Tilia x europaea Nutrition 0.000 description 3
- 238000003763 carbonization Methods 0.000 description 3
- 238000006243 chemical reaction Methods 0.000 description 3
- 238000009833 condensation Methods 0.000 description 3
- 230000005494 condensation Effects 0.000 description 3
- 238000005265 energy consumption Methods 0.000 description 3
- 239000004571 lime Substances 0.000 description 3
- UIIMBOGNXHQVGW-UHFFFAOYSA-M Sodium bicarbonate Chemical compound [Na+].OC([O-])=O UIIMBOGNXHQVGW-UHFFFAOYSA-M 0.000 description 2
- 238000009621 Solvay process Methods 0.000 description 2
- 239000003513 alkali Substances 0.000 description 2
- 239000000872 buffer Substances 0.000 description 2
- 239000003153 chemical reaction reagent Substances 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 238000002156 mixing Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000000630 rising effect Effects 0.000 description 2
- OYPRJOBELJOOCE-UHFFFAOYSA-N Calcium Chemical compound [Ca] OYPRJOBELJOOCE-UHFFFAOYSA-N 0.000 description 1
- 238000009835 boiling Methods 0.000 description 1
- 239000007853 buffer solution Substances 0.000 description 1
- 239000011575 calcium Substances 0.000 description 1
- 229910052791 calcium Inorganic materials 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000001704 evaporation Methods 0.000 description 1
- 230000008020 evaporation Effects 0.000 description 1
- 238000001914 filtration Methods 0.000 description 1
- 239000011777 magnesium Substances 0.000 description 1
- 159000000003 magnesium salts Chemical class 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 239000011259 mixed solution Substances 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 230000002035 prolonged effect Effects 0.000 description 1
- 230000036632 reaction speed Effects 0.000 description 1
- 238000004064 recycling Methods 0.000 description 1
- 230000037390 scarring Effects 0.000 description 1
- 239000013049 sediment Substances 0.000 description 1
- 239000011734 sodium Substances 0.000 description 1
- 235000017557 sodium bicarbonate Nutrition 0.000 description 1
- 229910000030 sodium bicarbonate Inorganic materials 0.000 description 1
- 238000005292 vacuum distillation Methods 0.000 description 1
- 238000005406 washing Methods 0.000 description 1
Abstract
The utility model discloses a recovery system of fixed ammonia of condensate of an ammonia distillation tower, which comprises a positive pressure ammonia distillation system, a negative pressure ammonia distillation system, a light liquid barrel, a flash evaporator and a light liquid tower. The positive pressure ammonia distillation system comprises a positive pressure ammonia distillation tower, a first ammonia condenser, a first ammonia cooler, a first separator and a first absorption tower; the negative pressure ammonia distillation system comprises a negative pressure ammonia distillation tower, a second ammonia condenser, a second ammonia cooler, a second separator and a second absorption tower. The heat medium liquid phase outlet of the second ammonia condenser connected with the negative pressure ammonia distillation tower is communicated with the liquid inlet at the upper part of the positive pressure ammonia distillation tower. The system has little change to the prior art, and the condensate formed after the ammonia gas of the mother liquor is condensed in the negative pressure ammonia distillation tower is conveyed to the positive pressure ammonia distillation tower to distill the fixed ammonia in the condensate, so that the ammonia can be recycled, the unnecessary ammonia loss in the process is reduced, and the content of the fixed ammonia entering the light liquid tower is also reduced.
Description
Technical field:
the utility model relates to the field of soda ash production by an ammonia-soda process, in particular to a recovery system for fixed ammonia of condensate liquid of an ammonia distillation tower.
The background technology is as follows:
in the process of preparing sodium carbonate, ammonia brine and CO are mixed in a carbonization tower 2 The gas is carbonated to generate sodium bicarbonate sediment and NH with low solubility 4 Cl solution, naHCO obtained by filtering and washing 3 The tiny crystal is heated and calcined again to obtain sodium carbonate product (Na 2 CO 3 ) Containing NH 4 The Cl solution is called mother liquor. In order to recycle the ammonia in the mother liquor, the mother liquor can be introduced into an ammonia distillation tower to distill the ammonia, the distilled ammonia is sent into an absorption tower to be refined with brineAbsorbing to prepare ammonia brine, and reusing the ammonia brine in the preparation process of sodium carbonate; the distilled ammonia gas contains a certain amount of water, and is changed into condensate after being cooled, and the condensate flows into a light liquid tower for treatment and then is reused.
The positive pressure ammonia distillation tower has high energy consumption, usually 1/3 of the energy consumption of the whole process for producing sodium carbonate by an ammonia-soda process, and medium corrosion is serious; therefore, a plurality of enterprises begin to introduce negative pressure or vacuum distillation processes, and the method is characterized in that the operation pressure value of a distillation system is reduced, even the whole distillation device can be operated under the pressure lower than the atmospheric pressure, not only can the energy consumption be reduced, but also the scarring of distillation sections of a pre-ash barrel and an ammonia distillation tower can be alleviated, and the operation period of equipment is prolonged. However, the operating pressure of the negative pressure or vacuum ammonia still is reduced, the boiling point of the mother liquor introduced into the ammonia still is reduced, the evaporation capacity is increased, a great amount of mother liquor can be entrained in the gas discharged from the ammonia still, and the mother liquor can enter the light liquor tower through condensate. Because the light liquid tower can only evaporate free ammonia and NH 4 Cl、(NH 4 ) 2 SO 4 The fixed ammonia is discharged along with the waste light liquid of the light liquid tower, so that on one hand, the loss of ammonia is caused; on the other hand, the main purpose of the waste dilute solution is salt dissolving, NH in the waste dilute solution 4 CI can generate a buffer effect with OH-ions in excess of magnesium salt removal water, so that ammonia buffer solution is easy to form, and Mg is caused 2+ Besides, the turbidity of the refined brine is increased, so that the quality of the refined brine is affected, for example, a large amount of gray milk is required to be added for breaking the buffer function, so that the amount of sodium carbonate used in the calcium removal process is greatly increased, the carbonization reaction speed is also affected when the fixed ammonia enters a carbonization system along with the refined brine, the refined brine yield is reduced, and the consumption of crude salt is increased. Thus, there is a need to recycle the fixed ammonia in the condensate of the negative pressure or vacuum ammonia still. However, if the condensate with the mother liquor is led into the top of the negative pressure ammonia still, part of the mother liquor enters the condenser along with the ammonia gas and then enters the light liquor tower along with the condensate, and the problem that the fixed ammonia in part of the mother liquor is discharged along with the waste light liquor of the light liquor tower cannot be solved.
The utility model comprises the following steps:
the utility model aims to provide a recovery system of fixed ammonia in condensate of an ammonia still, which has a simple structure, and can treat and recover the fixed ammonia in condensate of a negative pressure or vacuum ammonia still, so as to reduce ammonia loss.
The utility model is implemented by the following technical scheme:
a recovery system of fixed ammonia of ammonia still condensate, it includes positive pressure ammonia still system, negative pressure ammonia still system, light liquid bucket, light liquid tower; the positive pressure ammonia distillation system comprises a positive pressure ammonia distillation tower and a first pre-ash barrel; the liquid outlet of the preheating section of the positive pressure ammonia still is communicated with the liquid inlet of the first pre-ash barrel, the gas outlet of the first pre-ash barrel is communicated with the gas inlet of the preheating section of the positive pressure ammonia still, and the liquid outlet of the first pre-ash barrel is communicated with the liquid inlet of the ash adding distillation section of the positive pressure ammonia still; the heat medium liquid phase outlet of the second ammonia condenser of the negative pressure ammonia distillation system is communicated with the liquid inlet at the upper part of the positive pressure ammonia distillation tower of the positive pressure ammonia distillation system. In the traditional process, a large amount of mother liquor is entrained when the negative pressure ammonia distillation tower top is discharged, and fixed ammonia in the mother liquor can enter a light liquid tower along with condensate liquid, so that ammonia loss is caused, and the quality of refined salt in the subsequent process is influenced. If condensate with mother liquor is led into the top of the negative pressure ammonia still, part of the mother liquor still enters the second ammonia condenser along with ammonia gas and then enters the light liquor tower along with condensate. The positive pressure ammonia distillation tower is arranged in the alkali making workshop, condensate containing mother liquor of the second ammonia condenser of the negative pressure ammonia distillation system can be introduced into the top of the positive pressure ammonia distillation tower, on one hand, the top ammonia of the positive pressure ammonia distillation tower is washed, on the other hand, the condensate is subjected to heat exchange with vapor distilled from the lower layer of the positive pressure ammonia distillation tower, so that free ammonia in the condensate is distilled, the liquid is continuously preheated downwards, preheated mother liquor flows out of a preheating section of the positive pressure ammonia distillation tower and enters the upper part of the first pre-ash barrel, and is uniformly stirred and mixed with lime milk in the first pre-ash barrel to fully react, so that most of fixed ammonia is decomposed into free ammonia, and part of NH 3 、H 2 O steam escapes, enters the preheating section of the positive pressure ammonia still to be steamed out, after reaction, the blending liquid overflows from the liquid outlet of the first pre-ash barrel to the top ring of the ash adding distillation section of the positive pressure ammonia still, the liquid is in countercurrent contact heat exchange with hot steam from top to bottom through a block-by-block tray, almost all ammonia is steamed out, and the residual liquid is reduced toThe bottom ring becomes waste liquid and enters the first flash evaporator, so that the fixed ammonia in the condensate containing the mother liquid of the second condenser in the negative pressure ammonia distillation system is basically decomposed and distilled out.
Further, the positive pressure ammonia distillation system also comprises a first ammonia condenser, a first ammonia cooler, a first separator, a first absorption tower and a first flash evaporator; an ammonia outlet at the top of the positive pressure ammonia distillation tower is communicated with a heat medium inlet of the first ammonia condenser; the heat medium gas phase outlet of the first ammonia condenser is communicated with the heat medium inlet of the first ammonia cooler; the heat medium outlet of the first ammonia gas cooler is communicated with the feed inlet of the first separator; the gas phase outlet of the first separator is communicated with the ammonia gas inlet of the first absorption tower; the heat medium liquid phase outlet of the first ammonia condenser is communicated with the liquid inlet of the light liquid barrel; and a liquid outlet of the light liquid barrel is communicated with a liquid inlet of the light liquid tower. The ammonia evaporated from the positive pressure ammonia still enters the first ammonia condenser to be condensed, the temperature of the condensed ammonia still does not reach the requirement of entering the first absorption tower, so that the condensed ammonia enters the first ammonia cooler from a heat medium gas phase outlet of the first ammonia condenser, circulating water is used as a cooling medium to cool, the cooling medium returns to a circulating pipe network to be reused after cooling, the cooled ammonia enters the first separator, and the ammonia is conveyed to the first absorption tower to be continuously treated after the gas-liquid separation of the first separator. After the first ammonia condenser condenses, condensate flows out from a heat medium liquid phase outlet of the first ammonia condenser, enters the light liquid barrel and finally is sent into the light liquid tower for distillation.
Further, the positive pressure ammonia still is an ammonia still with a rectifying section.
Further, the liquid phase outlet of the first separator is communicated with the liquid inlet of the light liquid barrel. After the ammonia gas from the first ammonia gas cooler is subjected to solid-liquid separation by the first separator, liquid flows into the light liquid barrel and then enters the light liquid tower.
Further, the liquid outlet end of the mother liquor pipeline is communicated with the cold medium inlet of the first ammonia condenser, and the cold medium outlet of the first ammonia condenser is communicated with the liquid inlet at the lower part of the rectifying section of the positive pressure ammonia still. And the first ammonia condenser takes mother liquor as a cooling medium, absorbs heat by the mother liquor as the cooling medium after condensation, and introduces the heat into the lower part of the rectifying section of the positive pressure ammonia still for ammonia distillation.
Further, a waste liquid outlet at the bottom of the positive pressure ammonia still is communicated with a liquid inlet of a first flash evaporator, and a vapor outlet of the first flash evaporator is communicated with a vapor inlet of the light liquid tower. After the waste liquid from the positive pressure ammonia still is flashed by the first flasher, the formed steam enters the light liquid tower, ammonia gas, carbon dioxide gas and the like in the liquid are distilled out in countercurrent with the liquid from the light liquid bucket, and the gas enters an absorption tower after being treated by procedures such as cooling, gas-liquid separation and the like; and conveying the distilled liquid to a salt dissolving section for application.
Further, the negative pressure ammonia distillation system comprises a negative pressure ammonia distillation tower, a second ammonia condenser, a second ammonia cooler, a second separator, a second absorption tower, a second pre-ash bucket and a second flash evaporator; an ammonia outlet at the top of the negative pressure ammonia distillation tower is communicated with a heat medium inlet of the second ammonia condenser; the heat medium gas phase outlet of the second ammonia condenser is communicated with the heat medium inlet of the second ammonia cooler; the heat medium outlet of the second ammonia gas cooler is communicated with the feed inlet of the second separator; the gas phase outlet of the second separator is communicated with the ammonia gas inlet of the second absorption tower; the heat medium liquid phase outlet of the second ammonia condenser is communicated with the liquid inlet of the light liquid barrel; the liquid outlet of the heating decomposition section of the negative pressure ammonia still is communicated with the liquid inlet of the second pre-ash barrel, the gas outlet of the second pre-ash barrel is communicated with the gas inlet of the heating decomposition section of the negative pressure ammonia still, the liquid outlet of the second pre-ash barrel is communicated with the liquid inlet of the ash adding distillation section of the negative pressure ammonia still, and the gas outlet of the ash adding distillation section of the negative pressure ammonia still is communicated with the gas inlet of the second pre-ash barrel. The ammonia evaporated from the negative pressure ammonia still enters the second ammonia condenser to be condensed, the temperature of the condensed ammonia still does not reach the requirement of entering the second absorption tower, so that the condensed ammonia enters the second ammonia cooler from a heat medium gas phase outlet of the second ammonia condenser, circulating water is used as a cooling medium to cool, the cooling medium returns to a circulating pipe network to be reused after cooling, the cooled ammonia enters the second separator, and the ammonia is conveyed to the second absorption tower to be continuously treated after the second separator separates the gas from the liquid. And the condensate condensed by the second ammonia condenser flows out from a heat medium liquid phase outlet of the second ammonia condenser, enters the light liquid barrel and finally is sent into the light liquid tower for distillation.
Further, the liquid outlet end of the mother liquor pipeline is communicated with the cold medium inlet of the second ammonia condenser, and the cold medium outlet of the second ammonia condenser is communicated with the liquid inlet at the upper part of the negative pressure ammonia still. The second ammonia condenser takes mother liquor as a cooling medium, the mother liquor which is taken as the cooling medium absorbs heat after being condensed by the second ammonia condenser, ammonia is evaporated at the top of the negative pressure ammonia still, part of the mother liquor flows downwards, and ammonia and carbon dioxide in the mother liquor are distilled out after the reaction with the second pre-ash barrel through an ash adding distillation section of the negative pressure ammonia still; because the operating pressure of the negative pressure ammonia distillation tower is low, a large amount of mother liquor is entrained when the ammonia of the negative pressure ammonia distillation tower is discharged, the ammonia in the part of mother liquor is not distilled out, and as the ammonia is condensed by the second ammonia condenser, condensate containing the mother liquor enters the positive pressure ammonia distillation tower to distill the ammonia, and the ammonia of the positive pressure ammonia distillation tower is washed; in order to ensure that the light liquid tower has stable load, and under the condition that the condensate amount is large and the positive pressure ammonia distillation tower has limited capacity, part of condensate enters the light liquid barrel and finally enters the light liquid tower for distillation.
Further, a liquid phase outlet of the second separator is communicated with a liquid inlet of the light liquid barrel; the liquid phase outlet of the second separator is communicated with the liquid inlet at the upper part of the positive pressure ammonia still. After the ammonia gas from the second ammonia gas cooler is subjected to solid-liquid separation by the second separator, part of liquid enters the positive pressure ammonia distillation tower to distill ammonia; in order to ensure that the light liquid tower has stable load, and when the positive pressure ammonia distillation tower has limited capacity and the liquid amount entering the positive pressure ammonia distillation tower is large, the other part of separated liquid enters the light liquid barrel and finally enters the light liquid tower for distillation.
Further, a waste liquid outlet at the bottom of the negative pressure ammonia still is communicated with a liquid inlet of the second flash evaporator, and a steam outlet of the second flash evaporator is communicated with a steam inlet at the bottom of the negative pressure ammonia still. And after the waste liquid from the negative pressure ammonia still is flashed by the second flasher, the formed steam enters the bottom of the negative pressure ammonia still as supplementary steam.
The utility model has the advantages that:
the recovery system for the fixed ammonia of the condensate of the ammonia distillation tower provided by the utility model has small modification to the prior art, ammonia gas carried by mother liquor in the negative pressure ammonia distillation tower is condensed by the ammonia gas cooler, the condensate containing the fixed ammonia formed after the condensation is conveyed to the positive pressure ammonia distillation tower, and the fixed ammonia in the condensate is distilled out, so that the ammonia can be recycled, the ammonia loss in the process is reduced, the content of the fixed ammonia entering the dilute liquid tower is also reduced, and the reagent consumption and the influence on the quality of refined salt generated after the waste dilute liquid containing the fixed ammonia enters the salt dissolving process are reduced.
Description of the drawings:
in order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings that are required in the embodiments or the description of the prior art will be briefly described, it being obvious that the drawings in the following description are only some embodiments of the utility model, and that other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.
FIG. 1 is a schematic diagram of a recovery system for fixed ammonia from condensate in an ammonia still according to the present utility model.
The drawings are as follows: 10. a positive pressure ammonia still; 11. a first ammonia condenser; 12. a first ammonia gas cooler; 13. a first separator; 14. a first absorption tower; 15. a first flash; 16. a first pre-ash bucket; 20. a negative pressure ammonia distillation tower; 21. a second ammonia condenser; 22. a second ammonia gas cooler; 23. a second separator; 24. a second absorption tower; 25. a second flash; 26. a second pre-ash bucket; 3. a light liquid barrel; 4. and a light liquid tower.
The specific embodiment is as follows:
the following description of the embodiments of the present utility model will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present utility model, but not all embodiments. In the description of the present utility model, it should be noted that the terms "first," "second," and "second" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance. All other embodiments, which can be made by those skilled in the art based on the embodiments of the utility model without making any inventive effort, are intended to be within the scope of the utility model.
Examples
The recovery system of the condensate fixed ammonia of the ammonia still comprises a positive pressure ammonia still system, a negative pressure ammonia still system, a light liquid barrel 3 and a light liquid tower 4 as shown in figure 1.
The positive pressure ammonia distillation system comprises a positive pressure ammonia distillation tower 10, a first ammonia condenser 11, a first ammonia cooler 12, a first separator 13, a first absorption tower 14, a first flash evaporator 15 and a first pre-ash barrel 16. The positive pressure ammonia still 10 is an ammonia still with a rectifying section, and the model is phi 2800 multiplied by 39110 (mm). An ammonia outlet at the top of the positive pressure ammonia still 10 is communicated with a heat medium inlet of a first ammonia condenser 11; the heat medium gas phase outlet of the first ammonia condenser 11 is communicated with the heat medium inlet of the first ammonia cooler 12; the heat medium outlet of the first ammonia gas cooler 12 is communicated with the feed inlet of the first separator 13; the gas phase outlet of the first separator 13 is communicated with the ammonia gas inlet of the first absorption tower 14; the heat medium liquid phase outlet of the first ammonia condenser 11 is communicated with the liquid inlet of the light liquid barrel 3; the liquid outlet of the light liquid barrel 3 is communicated with the liquid inlet of the light liquid tower 4; the liquid outlet of the preheating section of the positive pressure ammonia still 10 is communicated with the liquid inlet of the first pre-ash barrel 16, the gas outlet of the first pre-ash barrel 16 is communicated with the gas inlet of the preheating section of the positive pressure ammonia still 10, and the liquid outlet of the first pre-ash barrel 16 is communicated with the liquid inlet of the ash adding distillation section of the positive pressure ammonia still 10. The liquid phase outlet of the first separator 13 is communicated with the liquid inlet of the light liquid barrel 3. The liquid outlet end of the mother liquor pipeline is communicated with the cold medium inlet of the first ammonia condenser 11, and the cold medium outlet of the first ammonia condenser 11 is communicated with the liquid inlet at the lower part of the rectifying section of the positive pressure ammonia still 10. The waste liquid outlet at the bottom of the positive pressure ammonia still 10 is communicated with the liquid inlet of the first flash evaporator 15, and the vapor outlet of the first flash evaporator 15 is communicated with the vapor inlet of the light liquid tower 4.
The negative pressure ammonia distillation system comprises a negative pressure ammonia distillation tower 20, a second ammonia condenser 21, a second ammonia cooler 22, a second separator 23, a second absorption tower 24, a second flash evaporator 25 and a second pre-ash barrel 26; the negative pressure ammonia still 20 is a sieve plate ammonia still with the model phi of 3000 multiplied by 39959 (mm), and an ammonia outlet at the top of the negative pressure ammonia still 20 is communicated with a heat medium inlet of the second ammonia condenser 21; the heat medium gas phase outlet of the second ammonia condenser 21 is communicated with the heat medium inlet of the second ammonia cooler 22; the heat medium outlet of the second ammonia gas cooler 22 is communicated with the feed inlet of the second separator 23; the gas phase outlet of the second separator 23 is communicated with the ammonia gas inlet of the second absorption tower 24; the heat medium liquid phase outlet of the second ammonia condenser 21 is communicated with the liquid inlet of the light liquid barrel 3. The liquid outlet of the heating decomposition section of the negative pressure ammonia still 20 is communicated with the liquid inlet of a second pre-ash barrel 26, the gas outlet of the second pre-ash barrel 26 is communicated with the gas inlet of the heating decomposition section of the negative pressure ammonia still 20, the liquid outlet of the second pre-ash barrel 26 is communicated with the liquid inlet of the ash adding distillation section of the negative pressure ammonia still 20, and the gas outlet of the ash adding distillation section of the negative pressure ammonia still 20 is communicated with the gas inlet of the second pre-ash barrel. The liquid outlet end of the mother liquor pipeline is communicated with the cold medium inlet of the second ammonia condenser 21, and the cold medium outlet of the second ammonia condenser 21 is communicated with the liquid inlet at the upper part of the negative pressure ammonia still 20. The liquid phase outlet of the second separator 23 is communicated with the liquid inlet of the light liquid barrel 3; the liquid phase outlet of the second separator 23 is communicated with the liquid inlet at the upper part of the positive pressure ammonia still 10. The waste liquid outlet at the bottom of the negative pressure ammonia still 20 is communicated with the liquid inlet of the second flash evaporator 25, and the vapor outlet of the second flash evaporator 25 is communicated with the vapor inlet at the bottom of the negative pressure ammonia still 20.
The heat medium liquid phase outlet of the second ammonia condenser 21 is communicated with the liquid inlet at the upper part of the positive pressure ammonia still 10.
When the system is running:
the ammonia evaporated from the positive pressure ammonia still 10 enters a first ammonia condenser 11, mother liquor is used as a cold medium for condensation, the temperature of the condensed ammonia still does not reach the requirement of entering a first absorption tower 14, so that the condensed ammonia enters a first ammonia cooler 12 from a heat medium gas phase outlet of the first ammonia condenser 11, circulating water is used as a cold medium for cooling, the cold medium returns to a circulating pipe network for recycling after cooling, and the cooled ammonia enters a first separator 13; after the gas-liquid separation of the first separator 13, the ammonia gas is conveyed to the first absorption tower 14 for continuous treatment, and the liquid flows into the light liquid barrel 3 and then enters the light liquid tower 4. After the first ammonia condenser 11 condenses, the mother liquor used as a cooling medium absorbs heat and is introduced into the lower part of the rectifying section of the positive pressure ammonia still 10 to evaporate ammonia; ammonia gas discharged from the positive pressure ammonia still 10 after ammonia distillation is condensed by a first ammonia condenser 11, condensate flows out from a heat medium liquid phase outlet of the first ammonia condenser 11, enters the light liquid barrel 3, and finally is sent into the light liquid tower 4 for distillation. The waste liquid from the positive pressure ammonia still 10 is flashed by a first flasher 15, the formed steam enters a light liquid tower 4, ammonia gas, carbon dioxide gas and the like in the liquid are distilled out in countercurrent with the liquid from the light liquid barrel 3, and the gas enters an absorption tower after being treated by procedures such as cooling, gas-liquid separation and the like; and conveying the distilled liquid to a salt dissolving section for application.
The ammonia evaporated from the negative pressure ammonia still 20 enters the second ammonia condenser 21 to be condensed, the temperature of the condensed ammonia still does not meet the requirement of entering the second absorption tower 24, so the condensed ammonia enters the second ammonia cooler 22 from the heat medium gas phase outlet of the second ammonia condenser 21, the circulating water is used as a cooling medium to be cooled, the cooling medium returns to a circulating pipe network to be recycled, the cooled ammonia enters the second separator 23, the second separator 23 separates the gas from the liquid, the ammonia is conveyed to the second absorption tower 24 to be continuously treated, and the liquid enters the light liquid barrel 3. The condensate condensed by the second ammonia condenser 21 flows out from the heat medium liquid phase outlet of the second ammonia condenser 21, enters the light liquid barrel 3, and finally is sent into the light liquid tower 4 for distillation.
The second ammonia condenser 21 takes mother liquor as a cold medium, the mother liquor as the cold medium absorbs heat after being condensed by the second ammonia condenser 21, and the heat is introduced into the top of the negative pressure ammonia still 20, and the heat exchange is carried out by countercurrent contact with rising steam, so that most of free ammonia and almost all carbon dioxide are evaporated to become preheated mother liquor; the preheated mother liquor flows out from the 24 th circle of the heating decomposition section of the negative pressure ammonia still 20, enters the middle part of the second pre-ash barrel 26, and fully reacts with lime milk sent by an ash dissolving station in the second pre-ash barrel 26, so that most of fixed ammonia is decomposed into free ammonia, part of free ammonia is resolved from a liquid phase, and enters the 25 th circle of the heating decomposition section of the negative pressure distillation tower through an air outlet pipe; the decomposed mixed solution enters into the upper 21 circles of tower plates at the upper part of the ash adding distillation section of the negative pressure distillation tower from the bottom of the second pre-ash barrel 26, and almost all ammonia is distilled out through countercurrent contact heat exchange between the tower plates and steam from top to bottom.
The mother liquor as a cold medium absorbs heat, and is introduced into the top of the negative pressure ammonia still 20 to be in countercurrent contact with rising steam, part of the mother liquor can be entrained to the second ammonia condenser 21 due to the fact that the air outlet at the top of the negative pressure ammonia still 20 is entrained, and fixed ammonia in the mother liquor can enter the light liquor tower 4 along with condensate, so that ammonia loss is caused, and the quality of refined salt in the subsequent process is affected. If condensate entrained with the mother liquor is re-introduced into the top of the negative pressure ammonia still 20, a portion of the mother liquor will still enter the second ammonia condenser 21 with ammonia and then enter the light liquor column 4 with condensate.
The positive pressure ammonia distillation tower 10 is arranged in the alkali production workshop, condensate containing mother liquor of the second ammonia condenser 21 can be introduced into the top of the positive pressure ammonia distillation tower 10, and liquid separated by the second separator 23 can be introduced into the positive pressure ammonia distillation tower 10 together; on the one hand, the top ammonia gas of the positive pressure ammonia still 10 is washed, on the other hand, the ammonia gas is subjected to heat exchange with steam evaporated from the lower layer of the positive pressure ammonia still 10, so that free ammonia in liquid is evaporated, then the liquid is continuously preheated downwards, preheated mother liquor flows out of a preheating section of the positive pressure ammonia still 10 and enters the upper part of a first pre-ash barrel 16, is uniformly stirred with lime milk in the first pre-ash barrel 16 and fully reacts, and most of fixed ammonia is decomposed into free ammonia, and part of NH is decomposed into 3 、H 2 O steam escapes, enters a preheating section of the positive pressure ammonia still 10 to be steamed, and after reaction, the blending liquid overflows from a liquid outlet of the first pre-ash barrel 16 to the ash adding distillation of the positive pressure ammonia still 10The top ring of the section, the liquid is subjected to countercurrent contact heat exchange with hot steam from top to bottom through the block-by-block tower plates, almost all ammonia is distilled out, the rest liquid is lowered to the bottom ring and becomes waste liquid to enter the first flash evaporator 15, and therefore the fixed ammonia in the condensate containing the mother liquor of the second ammonia condenser 21 and the fixed ammonia in the liquid separated by the second separator 23 are basically decomposed and distilled out. In order to ensure that the light liquid tower 4 has stable load, and when the condensate of the second ammonia condenser 21 and the liquid separated by the second separator 23 are large and the positive pressure ammonia distillation tower 10 has limited capacity, a part of condensate and the liquid separated by the second separator 23 enter the light liquid barrel 3 and finally enter the light liquid tower 4 for distillation. After the waste liquid from the negative pressure ammonia still 20 is flashed by the second flasher 25, the formed steam enters the bottom of the negative pressure ammonia still 20 as supplementary steam.
According to the measurement, the ammonia loss of mother liquor brought out by the negative pressure ammonia still 20 of 2022 year by the company is 0.513kg/t. If 58% of the total amount of condensate with mother liquor is introduced into the positive pressure ammonia still 10, the annual ammonia saving amount is 110 tons calculated as 37 ten thousand tons per year. In addition, the content of the fixed ammonia in the condensate is reduced, so that the reagent consumption and the influence on the quality of refined salt generated after the waste dilute solution containing the fixed ammonia enters the salt dissolving process can be reduced.
The foregoing description of the preferred embodiments of the utility model is not intended to be limiting, but rather is intended to cover all modifications, equivalents, alternatives, and improvements that fall within the spirit and scope of the utility model.
Claims (10)
1. The recovery system of the condensate fixed ammonia of the ammonia still is characterized by comprising a positive pressure ammonia still system, a negative pressure ammonia still system, a light liquid barrel and a light liquid tower;
the positive pressure ammonia distillation system comprises a positive pressure ammonia distillation tower and a first pre-ash barrel; the liquid outlet of the preheating section of the positive pressure ammonia still is communicated with the liquid inlet of the first pre-ash barrel, the gas outlet of the first pre-ash barrel is communicated with the gas inlet of the preheating section of the positive pressure ammonia still, and the liquid outlet of the first pre-ash barrel is communicated with the liquid inlet of the ash adding distillation section of the positive pressure ammonia still;
and a heat medium liquid phase outlet of a second ammonia condenser of the negative pressure ammonia distillation system is communicated with a liquid inlet at the upper part of the positive pressure ammonia distillation tower.
2. The ammonia still condensate fixed ammonia recovery system of claim 1, wherein the positive pressure ammonia still system further comprises a first ammonia condenser, a first ammonia cooler, a first separator, a first absorber, a first flash vessel; an ammonia outlet at the top of the positive pressure ammonia distillation tower is communicated with a heat medium inlet of the first ammonia condenser; the heat medium gas phase outlet of the first ammonia condenser is communicated with the heat medium inlet of the first ammonia cooler; the heat medium outlet of the first ammonia gas cooler is communicated with the feed inlet of the first separator; the gas phase outlet of the first separator is communicated with the ammonia gas inlet of the first absorption tower; the heat medium liquid phase outlet of the first ammonia condenser is communicated with the liquid inlet of the light liquid barrel; and a liquid outlet of the light liquid barrel is communicated with a liquid inlet of the light liquid tower.
3. The system for recovering fixed ammonia from a condensate of an ammonia still according to claim 2, wherein said positive pressure ammonia still is an ammonia still having a rectifying section.
4. The ammonia still condensate fixed ammonia recovery system of claim 2, wherein the liquid phase outlet of the first separator is in communication with the liquid inlet of the light liquid tank.
5. The ammonia still condensate fixed ammonia recovery system of claim 2, wherein a liquid outlet end of the mother liquor pipeline is communicated with a cold medium inlet of the first ammonia condenser, and a cold medium outlet of the first ammonia condenser is communicated with a liquid inlet at a lower part of the rectifying section of the positive pressure ammonia still.
6. The ammonia still condensate fixed ammonia recovery system of claim 2, wherein a waste liquid outlet at the bottom of the positive pressure ammonia still is in communication with a liquid inlet of the first flash evaporator, and a vapor outlet of the first flash evaporator is in communication with a vapor inlet of the light liquid column.
7. The ammonia still condensate fixed ammonia recovery system of claim 1, wherein the negative pressure ammonia still system comprises a negative pressure ammonia still, a second ammonia condenser, a second ammonia cooler, a second separator, a second absorber, a second pre-ash bucket, and a second flash vessel; an ammonia outlet at the top of the negative pressure ammonia distillation tower is communicated with a heat medium inlet of the second ammonia condenser; the heat medium gas phase outlet of the second ammonia condenser is communicated with the heat medium inlet of the second ammonia cooler; the heat medium outlet of the second ammonia gas cooler is communicated with the feed inlet of the second separator; the gas phase outlet of the second separator is communicated with the ammonia gas inlet of the second absorption tower; the heat medium liquid phase outlet of the second ammonia condenser is communicated with the liquid inlet of the light liquid barrel; the liquid outlet of the heating decomposition section of the negative pressure ammonia still is communicated with the liquid inlet of the second pre-ash barrel, the gas outlet of the second pre-ash barrel is communicated with the gas inlet of the heating decomposition section of the negative pressure ammonia still, the liquid outlet of the second pre-ash barrel is communicated with the liquid inlet of the ash adding distillation section of the negative pressure ammonia still, and the gas outlet of the ash adding distillation section of the negative pressure ammonia still is communicated with the gas inlet of the second pre-ash barrel.
8. The ammonia still condensate fixed ammonia recovery system of claim 7, wherein a liquid outlet end of the mother liquor pipeline is communicated with a cold medium inlet of the second ammonia condenser, and a cold medium outlet of the second ammonia condenser is communicated with a liquid inlet at an upper part of the negative pressure ammonia still.
9. The ammonia still condensate fixed ammonia recovery system of claim 7, wherein the liquid phase outlet of the second separator is in communication with the liquid inlet of the light liquid tank; the liquid phase outlet of the second separator is communicated with the liquid inlet at the upper part of the positive pressure ammonia still.
10. The ammonia still condensate fixed ammonia recovery system of claim 7, wherein a waste liquid outlet at the bottom of the negative pressure ammonia still is communicated with a liquid inlet of the second flash evaporator, and a vapor outlet of the second flash evaporator is communicated with a vapor inlet at the bottom of the negative pressure ammonia still.
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| CN202321376761.8U CN219964416U (en) | 2023-05-31 | 2023-05-31 | Recovery system for ammonia fixed in condensate of ammonia still |
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| CN202321376761.8U CN219964416U (en) | 2023-05-31 | 2023-05-31 | Recovery system for ammonia fixed in condensate of ammonia still |
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