CN107140613B - Method and device for preparing phosphoric acid by thermal method and recovering heat energy - Google Patents
Method and device for preparing phosphoric acid by thermal method and recovering heat energy Download PDFInfo
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- CN107140613B CN107140613B CN201710498011.0A CN201710498011A CN107140613B CN 107140613 B CN107140613 B CN 107140613B CN 201710498011 A CN201710498011 A CN 201710498011A CN 107140613 B CN107140613 B CN 107140613B
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- NBIIXXVUZAFLBC-UHFFFAOYSA-N Phosphoric acid Chemical compound OP(O)(O)=O NBIIXXVUZAFLBC-UHFFFAOYSA-N 0.000 title claims abstract description 175
- 229910000147 aluminium phosphate Inorganic materials 0.000 title claims abstract description 88
- 238000000034 method Methods 0.000 title claims abstract description 51
- 239000007789 gas Substances 0.000 claims abstract description 127
- OBSZRRSYVTXPNB-UHFFFAOYSA-N tetraphosphorus Chemical compound P12P3P1P32 OBSZRRSYVTXPNB-UHFFFAOYSA-N 0.000 claims abstract description 73
- 238000006243 chemical reaction Methods 0.000 claims abstract description 52
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 46
- 239000006096 absorbing agent Substances 0.000 claims abstract description 41
- 239000008234 soft water Substances 0.000 claims abstract description 36
- 239000003795 chemical substances by application Substances 0.000 claims abstract description 33
- 230000000887 hydrating effect Effects 0.000 claims abstract description 33
- 238000006703 hydration reaction Methods 0.000 claims abstract description 31
- 238000011084 recovery Methods 0.000 claims abstract description 31
- 239000007788 liquid Substances 0.000 claims abstract description 28
- 239000000203 mixture Substances 0.000 claims abstract description 24
- 239000007791 liquid phase Substances 0.000 claims abstract description 23
- 239000012071 phase Substances 0.000 claims abstract description 22
- 229920006395 saturated elastomer Polymers 0.000 claims abstract description 19
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims abstract description 11
- 229910052760 oxygen Inorganic materials 0.000 claims abstract description 11
- 239000001301 oxygen Substances 0.000 claims abstract description 11
- 239000007800 oxidant agent Substances 0.000 claims abstract description 8
- 230000001590 oxidative effect Effects 0.000 claims abstract description 8
- 238000001704 evaporation Methods 0.000 claims abstract description 5
- 230000008020 evaporation Effects 0.000 claims abstract description 5
- DLYUQMMRRRQYAE-UHFFFAOYSA-N tetraphosphorus decaoxide Chemical compound O1P(O2)(=O)OP3(=O)OP1(=O)OP2(=O)O3 DLYUQMMRRRQYAE-UHFFFAOYSA-N 0.000 claims description 56
- 239000002250 absorbent Substances 0.000 claims description 40
- 230000002745 absorbent Effects 0.000 claims description 40
- 239000006185 dispersion Substances 0.000 claims description 38
- 238000002485 combustion reaction Methods 0.000 claims description 20
- 238000000926 separation method Methods 0.000 claims description 20
- 239000000463 material Substances 0.000 claims description 15
- 238000005406 washing Methods 0.000 claims description 12
- OAICVXFJPJFONN-UHFFFAOYSA-N Phosphorus Chemical compound [P] OAICVXFJPJFONN-UHFFFAOYSA-N 0.000 claims description 6
- 230000014759 maintenance of location Effects 0.000 claims description 6
- 229910052698 phosphorus Inorganic materials 0.000 claims description 6
- 239000011574 phosphorus Substances 0.000 claims description 6
- 238000002360 preparation method Methods 0.000 claims description 3
- 230000036571 hydration Effects 0.000 description 14
- 239000002253 acid Substances 0.000 description 12
- 238000004519 manufacturing process Methods 0.000 description 12
- 238000005516 engineering process Methods 0.000 description 8
- 239000000243 solution Substances 0.000 description 7
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 6
- 230000009286 beneficial effect Effects 0.000 description 5
- 239000000126 substance Substances 0.000 description 5
- 238000012360 testing method Methods 0.000 description 5
- 238000010521 absorption reaction Methods 0.000 description 4
- 239000002994 raw material Substances 0.000 description 4
- 238000005201 scrubbing Methods 0.000 description 4
- 229910019142 PO4 Inorganic materials 0.000 description 3
- 230000010354 integration Effects 0.000 description 3
- 229910052757 nitrogen Inorganic materials 0.000 description 3
- NBIIXXVUZAFLBC-UHFFFAOYSA-K phosphate Chemical compound [O-]P([O-])([O-])=O NBIIXXVUZAFLBC-UHFFFAOYSA-K 0.000 description 3
- 239000010452 phosphate Substances 0.000 description 3
- 229920000137 polyphosphoric acid Polymers 0.000 description 3
- 238000004064 recycling Methods 0.000 description 3
- 238000011160 research Methods 0.000 description 3
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 2
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 2
- 239000007864 aqueous solution Substances 0.000 description 2
- 230000007797 corrosion Effects 0.000 description 2
- 238000005260 corrosion Methods 0.000 description 2
- -1 electronics Substances 0.000 description 2
- 239000012535 impurity Substances 0.000 description 2
- 230000003472 neutralizing effect Effects 0.000 description 2
- 239000002367 phosphate rock Substances 0.000 description 2
- OJMIONKXNSYLSR-UHFFFAOYSA-N phosphorous acid Chemical compound OP(O)O OJMIONKXNSYLSR-UHFFFAOYSA-N 0.000 description 2
- 239000007921 spray Substances 0.000 description 2
- 238000012546 transfer Methods 0.000 description 2
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 description 1
- 230000004913 activation Effects 0.000 description 1
- 229910052799 carbon Inorganic materials 0.000 description 1
- 238000012824 chemical production Methods 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 208000012839 conversion disease Diseases 0.000 description 1
- 238000000354 decomposition reaction Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 239000003814 drug Substances 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000005265 energy consumption Methods 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 238000000605 extraction Methods 0.000 description 1
- 239000003337 fertilizer Substances 0.000 description 1
- 239000012847 fine chemical Substances 0.000 description 1
- 239000002925 low-level radioactive waste Substances 0.000 description 1
- 238000005272 metallurgy Methods 0.000 description 1
- 238000002156 mixing Methods 0.000 description 1
- 239000002105 nanoparticle Substances 0.000 description 1
- 229910017604 nitric acid Inorganic materials 0.000 description 1
- 239000003208 petroleum Substances 0.000 description 1
- 230000000704 physical effect Effects 0.000 description 1
- 238000004886 process control Methods 0.000 description 1
- 238000000746 purification Methods 0.000 description 1
- 230000002787 reinforcement Effects 0.000 description 1
- 230000002194 synthesizing effect Effects 0.000 description 1
- 238000010977 unit operation Methods 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
- C01B25/00—Phosphorus; Compounds thereof
- C01B25/16—Oxyacids of phosphorus; Salts thereof
- C01B25/18—Phosphoric acid
- C01B25/20—Preparation from elemental phosphorus or phosphoric anhydride
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F22—STEAM GENERATION
- F22B—METHODS OF STEAM GENERATION; STEAM BOILERS
- F22B1/00—Methods of steam generation characterised by form of heating method
- F22B1/02—Methods of steam generation characterised by form of heating method by exploitation of the heat content of hot heat carriers
- F22B1/18—Methods of steam generation characterised by form of heating method by exploitation of the heat content of hot heat carriers the heat carrier being a hot gas, e.g. waste gas such as exhaust gas of internal-combustion engines
-
- 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
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P20/00—Technologies relating to chemical industry
- Y02P20/10—Process efficiency
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- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Sustainable Development (AREA)
- Combustion & Propulsion (AREA)
- Life Sciences & Earth Sciences (AREA)
- Inorganic Chemistry (AREA)
- Sustainable Energy (AREA)
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Gas Separation By Absorption (AREA)
- Treating Waste Gases (AREA)
Abstract
The invention discloses a method for preparing phosphoric acid by a thermal method and recovering heat energy and a device thereof, wherein the method uses a micro absorber to absorb heat of reaction heat of hydration reaction, the reaction heat is brought into a separating tank by a gas-liquid mixture after passing through the micro absorber, the heat of gas phase and liquid phase is absorbed respectively by tail gas heat recovery equipment and a concentrated phosphoric acid cooler, then the heat of the gas phase and the liquid phase is neutralized, and finally the heat is conveyed to an evaporation device of a yellow phosphorus boiler in a saturated soft water form for steam, so that the heat energy can be recovered while the phosphoric acid is prepared; the mass of oxygen in the oxidant is 1.2-2.6 times of that of yellow phosphorus, and the hydrating agent is water or different P 2 O 5 The mass fraction of the solution is 0.29-6 times of that of yellow phosphorus, and the mass of the water for preparing saturated soft water is 1-20 times of that of yellow phosphorus.
Description
Technical Field
The invention relates to a method and a device for preparing phosphoric acid by a thermal method and recovering heat energy, belonging to the technical field of phosphoric acid preparation and low-level heat energy recovery and utilization.
Background
Phosphoric acid is an important chemical intermediate, is a common raw material for synthesizing most of phosphate and partial phosphate and other phosphorus-containing compounds, and is widely applied to industries such as food, medicine, electronics, petroleum, metallurgy, chemical industry and the like. Depending on the production process, the source of phosphoric acid is wet-process phosphoric acid and hot-process phosphoric acid. Wet phosphoric acid is produced by double decomposition of strong acid, usually sulfuric acid, nitric acid, hydrochloric acid, fluosilicic acid and phosphorite to obtain coarse phosphoric acid with high impurity content, and is generally used for fertilizer. After the phosphoric acid is purified, food grade phosphoric acid can be obtained; the phosphoric acid is obtained by reducing phosphorite with carbon at high Wen Xiali to obtain yellow phosphorus, then burning the yellow phosphorus to obtain phosphorus pentoxide, and then reacting with water. The hot phosphoric acid has few impurities, and is almost the only raw material of the fine phosphate product before the popularization of the wet phosphoric acid purification technology. From the process flow, compared with hot phosphoric acid, the wet phosphoric acid has long and complex process flow, and has more unit operations and supporting facilities. However, wet phosphoric acid is economically advantageous over hot phosphoric acid, and an important reason for the high cost of hot phosphoric acid is the high energy consumption of production. The traditional hot phosphoric acid production process is quite extensive. The heat of reaction of yellow phosphorus combustion and hydration is directly removed by low-temperature circulating water, becomes low-level waste heat and is difficult to utilize, and in recent years, in order to reduce the cost of hot phosphoric acid, the recovery of heat released by yellow phosphorus phosphoric acid is becoming more and more interesting, and only a few related researches and practices have been carried out, for example:
the invention patent CN1355133A yellow phosphorus combustion heat energy recycling device and a hot phosphoric acid production system thereof provide a boiler-like combustion heat energy recycling device and a hot phosphoric acid production system. The emphasis of this patent is on the introduction of the device for the combustion heat recovery device, and the consideration of the heat recovery process of the high-temperature tail gas after leaving the device fails to completely jump out of the mode of the traditional hydration tower. Because of the different physical properties and flow rates of the gas phase and the liquid phase, the heat efficiency of the hydration tower with the jacket for heat exchange with the gas phase and the liquid phase is very limited. In addition, the kind of absorbent in the hydration tower is not specified in the claims, only the direct water is mentioned in the examples, and no tail gas treatment is mentioned.
The invention patent CN201531862U yellow phosphorus combustion heat energy recovery device provides a safer yellow phosphorus combustion heat energy recovery device, which uses a certain gas as an intermediate heat exchange medium, and can effectively avoid corrosion of equipment caused by phosphoric acid generated by the reaction of phosphorus pentoxide and soft water due to the rupture of a boiler heat exchange calandria, and the patent does not mention the recovery of hydration heat and heat integration.
The invention patent CN105731405A discloses a device for producing phosphoric acid by a thermal method with low-level heat energy recovery, which can recover partial hydration heat energy, and the obtained vapor pressure is 0.8MPa at most, and the heat recovery and heat integration of the unremoved tail gas are realized.
The invention patent CN102910602A discloses a device for efficiently recovering yellow phosphorus combustion heat energy, which is similar to a heat energy recovery device of a phosphorus combustion boiler, and does not consider recovery of high-temperature tail gas heat energy and hydration reaction heat of the device.
The invention patent CN102556990A discloses a device for absorbing yellow phosphorus combustion heat energy by heat conduction oil, which is used for heat exchange and releasing heat.
At present, the reports of related patents and documents are mostly focused on the technology and equipment for recovering the combustion heat energy of yellow phosphorus, but the recovery of hydration heat energy and final tail gas with heat is hardly noticed, and the heat integration of the whole process system for preparing phosphoric acid or polyphosphoric acid with different concentrations by taking yellow phosphorus as a raw material is not mentioned, so that the energy recovery rate is not high.
Among them, the use of hydration heat is very difficult in the conventional thermal acid process. In order to avoid equipment corrosion, the traditional thermal acid process adopts a large amount of cold circulation acid as an absorbent to absorb phosphorus pentoxide in a spray tower so as to control the temperature of the materials to be not more than 80 ℃. Heat at 80 ℃ is difficult to use. Therefore, the temperature of the material during absorption must be increased, and more expensive equipment materials must be selected; for large plants, material upgrades mean an increase in equipment investment, which impairs the benefits of heat recovery. For this reason, it is necessary to minimize the volume of the apparatus.
Microreaction technology is a new technology that enhances process delivery, precise process control, which has been increasingly focused in recent years. Along with the continuous progress of research on micro-chemical technology such as micro-mixing and multiphase micro-flow, micro-heat exchange and mass transfer, micro-scale reaction and the like, the micro-chemical technology is widely applied to various research fields such as chemistry, chemical industry, materials, energy sources, environment and the like, and industrial application is realized in the fields such as large-scale controllable preparation of nano particles, reinforcement of extraction and separation processes, fine chemical production and the like; one of the meanings of the bright spot 'micro' of the technology is that the space size of the process or the characteristic size of the micro reactor is extremely small compared with the traditional large-scale equipment such as towers, tanks and the like under the same production intensity, so that the miniaturization, the refinement and the flexible activation of a factory are possible. The nature of the system varies for different processes, and the degree of "micro" varies, so that the characteristic size of the mixture ratio is an important parameter in the specific process application of the micro-reaction technology.
The hydration process in the hot phosphoric acid production process is a reaction absorption process. The reaction is carried out by reacting phosphorus pentoxide with water, phosphorus pentoxide reflected in a gas phase is absorbed, the inlet of the gas phase material is mixed gas of nitrogen, oxygen and gaseous phosphorus pentoxide, the outlet is mainly nitrogen and oxygen, the absorbent is mainly aqueous solution containing phosphoric acid or polyphosphoric acid, the outlet concentration is higher than that of the inlet, and at present, no micro-reactor aiming at the system exists, therefore, the micro-reactor is introduced into the process, and the characteristic size of the micro-reactor is provided.
Disclosure of Invention
The invention aims to solve the technical problems of providing a method and a device for preparing phosphoric acid by a thermal method and recovering heat energy, which can improve the recovery rate of combustion heat of yellow phosphorus and reaction heat of phosphorus pentoxide, are beneficial to saving energy sources, effectively reduce the production cost and can overcome the defects of the prior art.
The technical scheme of the invention is as follows: a method for preparing phosphoric acid by a thermal method and recovering heat energy is characterized in that yellow phosphorus is contacted with an oxidant to generate combustion reaction to generate gas containing phosphorus pentoxide, and the gas containing phosphorus pentoxide is contacted with a hydrating agent to generate hydration reaction, and the method is characterized in that: the method uses a micro absorber to absorb heat of reaction heat of hydration reaction, the heat of reaction is brought into a separation tank by a gas-liquid mixture after passing through the micro absorber, the heat of gas phase and liquid phase is absorbed respectively by tail gas heat recovery equipment and a concentrated phosphoric acid cooler, then the heat of the gas phase and the liquid phase is neutralized, and finally the heat is conveyed to an evaporation device of a yellow phosphorus boiler in a saturated soft water form for steam, so that the heat energy can be recovered while the phosphoric acid is prepared; the mass of oxygen in the oxidant is 1.2-2.6 times of that of yellow phosphorus, the hydrating agent is water or solution with different P2O5 mass fractions, the mass of water in the hydrating agent is 0.29-6 times of that of yellow phosphorus, and the mass of water for preparing saturated soft water is 1-20 times of that of yellow phosphorus.
The gas containing phosphorus pentoxide contacts with the hydrating agent, and the hydrating agent is added at one time or added again after the first time, and is separated from the gas and liquid at the downstream of the liquid phase.
The tail gas heat recovery device comprises a tail gas cooler and an 85 phosphoric acid cooler, the gas absorbs heat through the tail gas cooler, then the cooled tail gas is sent to the tail gas scrubber for washing, the consumption of washing water is 0.29-6 times of the mass of yellow phosphorus, and the washed water is used for hydration reaction.
The device for preparing phosphoric acid by a thermal method and recovering heat energy comprises a yellow phosphorus boiler, wherein an outlet of the yellow phosphorus boiler is connected with a gas inlet end of a micro absorber, an absorbent inlet and a gas-liquid mixture outlet are arranged on the micro absorber, the gas-liquid mixture outlet is connected with a separation tank, a gas phase outlet of the separation tank is connected with a tail gas cooler, the tail gas cooler is connected with a gas treatment device, a liquid phase outlet of the separation tank is connected with a concentrated phosphoric acid cooler, the tail gas cooler is provided with a soft water inlet and a preheated soft water outlet, the preheated soft water outlet is sequentially connected with the 85 phosphoric acid cooler and the concentrated phosphoric acid cooler through pipelines, and a saturated soft water outlet of the concentrated phosphoric acid cooler is connected with a steam device of the yellow phosphorus boiler.
The micro absorber comprises a bottom plate and a cover plate, wherein one reaction plate is arranged in the bottom plate and the cover plate, an absorbent inlet is formed in the corner of the cover plate, absorbent channels are formed in the corresponding positions of the reaction plate, parallel channels are uniformly distributed on the upper plate surfaces of the bottom plate and the reaction plate, a dispersion plate perpendicular to the direction of the parallel channels is arranged at the absorbent channels, dispersion holes are formed in the dispersion plate, grooves embedded in the dispersion plate are formed in the bottom of the reaction plate, a gas inlet is formed in the bottom plate on the same side as the absorbent channels, and a gas-liquid mixture outlet is formed in the reaction plate on one side far away from the absorbent channels.
The hydraulic radius of the parallel channel is 0.05mm-10mm, the radius of the dispersion hole is 0.01mm-2mm, the included angle between the axis of the dispersion hole and the axis of the parallel channel is 20-90 degrees, and the retention time of the material is 1s-60s.
Compared with the prior art, the method for preparing the phosphoric acid by the thermal method and recovering the heat energy comprises the steps of absorbing the reaction heat of hydration reaction by using a micro absorber, taking the reaction heat into a separation tank by a gas-liquid mixture after passing through the micro absorber, respectively absorbing the heat of a gas phase and a liquid phase by using tail gas heat recovery equipment and a concentrated phosphoric acid cooler, neutralizing the heat of the gas phase and the liquid phase, and finally conveying the heat of the gas phase and the liquid phase to an evaporation device of a yellow phosphorus boiler in a saturated soft water form for steam, so that the heat energy can be recovered while the phosphoric acid is prepared; according to the method, the recovery rate of combustion heat of yellow phosphorus and reaction heat of phosphorus pentoxide can be improved, tests prove that 95% of the reaction heat released by phosphoric acid production by using the method by taking yellow phosphorus as a raw material is recycled, the pressure of generated steam can be higher than 1.0MPa, and meanwhile, the heat recovery rate is effectively improved by adopting a microreactor;
the quality of oxygen in the oxidant is 1.2-2.6 times of that of yellow phosphorus, the hydrating agent is water or solution with different P2O5 mass fractions, the quality of water in the hydrating agent is 0.29-6 times of that of yellow phosphorus, and the quality of water for preparing saturated soft water is 1-20 times of that of yellow phosphorus, so that the data is a key data set which is obtained by the applicant through multiple experiments and is economic and energy-saving and does not influence the quality of products;
the gas containing phosphorus pentoxide contacts with the hydrating agent, and the hydrating agent is added once or added again from the downstream of the liquid phase separated from the gas and the liquid after the first addition, so that the added hydrating agent is beneficial to the reaction;
the tail gas heat recovery device comprises a tail gas cooler and an 85 phosphoric acid cooler, the gas is sent to the tail gas scrubber for scrubbing after absorbing heat by the tail gas cooler, the consumption of the scrubbing water is 0.29-6 times of the mass of yellow phosphorus, the scrubbed water is used for hydration reaction, the consumption of the scrubbing water can ensure the scrubbing effect of the tail gas, the emission standard of the tail gas is ensured, and meanwhile, the circulated use water is beneficial to saving economic cost;
the outlet of the yellow phosphorus boiler with the structure is connected with the gas inlet end of the micro absorber, the micro absorber is provided with an absorbent inlet and a gas-liquid mixture outlet, the gas-liquid mixture outlet is connected with a separating tank, the gas-phase outlet of the separating tank is connected with a tail gas cooler, the tail gas cooler is connected with a gas treatment device, the liquid-phase outlet of the separating tank is connected with a concentrated phosphoric acid cooler, the tail gas cooler is provided with a soft water inlet and a preheated soft water outlet, the preheated soft water outlet is sequentially connected with the 85 phosphoric acid cooler and the concentrated phosphoric acid cooler through pipelines, the saturated soft water outlet of the concentrated phosphoric acid cooler is connected with a steam device of the yellow phosphorus boiler, most of reaction heat of combustion and hydration reaction is recovered uniformly by the device, especially, the heat recovery is also carried out on the tail gas, and the grade of regenerated heat energy is high, which is shown in that the pressure of generated steam is more than 1.0MPa, thus the device can be used as power of a factory and a heat source;
the micro absorber comprises a bottom plate and a cover plate, wherein a reaction plate is arranged on the bottom plate and the cover plate, an absorbent inlet is arranged at the corner of the cover plate, absorbent channels are arranged at corresponding positions of the reaction plate, parallel channels are uniformly distributed on the upper plate surfaces of the bottom plate and the reaction plate, a dispersion plate perpendicular to the direction of the parallel channels is arranged at the absorbent channels, dispersion holes are formed in the dispersion plate, a groove embedded in the dispersion plate is formed in the bottom of the reaction plate, a gas inlet is formed in the bottom plate on the same side as the absorbent channels, a gas-liquid mixture outlet is formed in the reaction plate on the side far away from the absorbent channels, and most of reaction heat generated by phosphorus pentoxide and a hydrating agent is taken away by phosphoric acid mixture by the micro absorber, and a small part of reaction heat is stored in the gas phase, so that the heat recovery in the next process is facilitated; a dispersion plate for distributing an absorbent into each of the strip-shaped micro-channels so as to increase the surface area contacted by the gas;
the dispersion holes are used for allowing the absorbent to pass through the dispersion plate so as to distribute the absorbent into each strip-shaped micro-channel;
the parallel channels provide a place for the contact and flow of gas and absorbent;
the hydraulic radius of the parallel channel is 0.05mm-10mm, the radius of the dispersion hole is 0.01mm-2mm, the included angle between the axis of the dispersion hole and the axis of the parallel channel is 20-90 degrees, the retention time of materials is 1s-60s, so that the micro absorber with the size can better absorb heat, and is beneficial to improving the heat recovery efficiency, meanwhile, compared with the traditional spray absorption tower, the mass transfer rate of the micro absorber is fast, the reaction conversion rate is high, the production strength is greatly improved, the equipment volume is obviously reduced, the reduction of the equipment volume means that the liftable space of the material performance is large, the excellent materials are the key for ensuring the high hydration absorption temperature and the utilizable hydration heat, and the other advantages of small equipment volume are that: the investment is saved, the liquid holdup is low, the operation is flexible, and the process condition is controlled rapidly and accurately.
Drawings
Fig. 1 is a schematic structural view of the present invention.
Fig. 2 is a schematic diagram of a micro absorber.
Fig. 3 is a schematic structural view of the dispersion plate.
FIG. 4 is a schematic structural view of a reaction plate.
Wherein, the yellow phosphorus boiler 1; a micro absorber 2; a separation tank 3; an exhaust gas cooler 4; a tail gas scrubber 5; a concentrated phosphoric acid cooler 6;85 phosphoric acid cooler 7; an acid circulation pump 8; a wash water circulation pump 9; an exhaust fan 10.
Detailed Description
The invention relates to a method for preparing phosphoric acid by a thermal method and recovering heat energy, which comprises the steps of contacting yellow phosphorus with an oxidant to generate combustion reaction, generating gas containing phosphorus pentoxide, contacting the gas containing phosphorus pentoxide with a hydrating agent to generate hydration reaction, absorbing reaction heat of the hydration reaction by a micro absorber 2, taking the reaction heat into a separation tank 3 by a gas-liquid mixture after passing through the micro absorber 2, respectively absorbing heat of a gas phase and a liquid phase by a tail gas heat recovery device and a concentrated phosphoric acid cooler 6, neutralizing the heat of the gas phase and the liquid phase, and finally conveying the heat of the gas phase and the liquid phase to an evaporation device of a yellow phosphorus boiler 1 in a saturated soft water form to steam, so that the heat energy can be recovered while the phosphoric acid is prepared; the mass of oxygen in the oxidant is 1.2-2.6 times of that of yellow phosphorus, the hydrating agent is water or solution with different P2O5 mass fractions, the mass of water in the hydrating agent is 0.29-6 times of that of yellow phosphorus, the mass of water in the prepared saturated soft water is 1-20 times of that of yellow phosphorus, wherein gas containing phosphorus pentoxide contacts with the hydrating agent, and the required hydrating agent is added at one time or added again from the downstream of a liquid phase separated from gas and liquid after the first addition; the tail gas heat recovery device comprises a tail gas cooler 4 and a 85 phosphoric acid cooler 7, the gas absorbs heat through the tail gas cooler 4 and then sends cooled tail gas to a tail gas washer 5 for washing, the consumption of washing water is 0.29-6 times of the mass of yellow phosphorus, and the washed water is used for hydration reaction.
The device for preparing phosphoric acid by a thermal method and recovering heat energy is shown in a figure 1, and structurally comprises a yellow phosphorus boiler 1, wherein an outlet of the yellow phosphorus boiler 1 is connected with a gas inlet end of a micro absorber 2, an absorbent inlet and a gas-liquid mixture outlet are arranged on the micro absorber 2, the gas-liquid mixture outlet is connected with a separation tank 3, a gas phase outlet of the separation tank 3 is connected with a tail gas cooler 4, the tail gas cooler 4 is connected with a gas treatment device, a liquid phase outlet of the separation tank 3 is connected with a concentrated phosphoric acid cooler 6, the tail gas cooler 4 is provided with a soft water inlet and a preheated soft water outlet, the preheated soft water outlet is sequentially connected with a 85 phosphoric acid cooler 7 and a concentrated phosphoric acid cooler 6 through pipelines, and a saturated soft water outlet of the concentrated phosphoric acid cooler 6 is connected with a steam device of the yellow phosphorus boiler 1.
The micro absorber 2 comprises a bottom plate and a cover plate, wherein a reaction plate is arranged on the bottom plate and the cover plate, an absorbent inlet is arranged at the corner of the cover plate, absorbent channels are arranged at corresponding positions of the reaction plate, parallel channels are uniformly distributed on the upper plate surfaces of the bottom plate and the reaction plate, a dispersion plate perpendicular to the direction of the parallel channels is arranged at the absorbent channels, dispersion holes are formed in the dispersion plate, grooves embedded in the dispersion plate are formed in the bottom of the reaction plate, a gas inlet is formed in the bottom plate on the same side as the absorbent channels, a gas-liquid mixture outlet is formed in the reaction plate on the side far away from the absorbent channels, the hydraulic radius of the parallel channels is 0.05-10 mm, the radius of the dispersion holes is 0.01-2 mm, the included angle between the axes of the dispersion holes and the axes of the parallel channels is 20-90 degrees, and the retention time of materials is 1s-60s.
The invention discloses a method for preparing phosphoric acid by a thermal method and recovering heat energy and a device thereof, wherein the process principle is as shown in figure 1, and liquid yellow phosphorus of 5.5t/h is atomized and then contacts 11.7Nm < 3 >/s air in a yellow phosphorus boiler 1 for combustion. The heat released by the combustion is absorbed by the soft water or steam in the boiler to produce saturated steam or superheated steam, while the phosphorus pentoxide-containing gas, boiler tail gas, is cooled. The phosphorus pentoxide in the cooled boiler tail gas reacts with a hydrating agent in the micro absorber 2 to generate phosphoric acid or polyphosphoric acid solution, namely concentrated phosphoric acid, and meanwhile unreacted oxygen and nitrogen are accompanied with hydration tail gas. The hydrating agent is aqueous solution with the mass fraction of P2O5 being more than 61.58 percent, and the gas-liquid mixture discharged from the micro absorber 2 is separated in the separating tank 3. The gas phase-hydration tail gas is discharged from the top after defogging, heat is recovered by the tail gas cooler 4, then the gas phase-hydration tail gas is purified and defogged by the tail gas scrubber 5, finally the gas phase-hydration tail gas is pumped out and discharged to the atmosphere by the tail gas fan 10, and the washing water at the bottom of the tail gas scrubber 5 is partially circulated to the upper part of the tail gas scrubber 5 and mixed with desalted water to be used as the water inlet of the tail gas scrubber 5 while the other part is used for preparing the hydrating agent required by the micro absorber 2 under the conveying of the washing water circulating pump 9. After heat is recovered from the concentrated phosphoric acid at the lower part of the separation tank 3 through the concentrated phosphoric acid cooler 6, one part of the concentrated phosphoric acid is sent by the acid circulating pump 8 to be mixed with washing water entering the micro absorber 2 to form a hydrating agent entering the micro absorber 2, and the other part of the concentrated phosphoric acid is sent by the acid circulating pump 8 to be mixed with desalted water serving as a secondary hydrating agent to realize secondary hydration to generate heat 85 acid. The hot 85 acid is transformed into cold 85 acid, commercial phosphoric acid, after heat recovery by 85 phosphoric acid cooler 7. Soft water required by the boiler flows through the tail gas cooler 4, the 85 phosphoric acid cooler 7 and the concentrated phosphoric acid cooler 6 in series in sequence to recover heat of hydration tail gas, hot 85 acid and concentrated phosphoric acid respectively, and then enters the boiler to absorb combustion heat and turns into steam as described above.
Use of the micro absorber 2: the absorbent is added from the absorbent inlet, passes through the gaps below the cover plate and the reaction plates of each layer, passes through the small holes on the separation plates, and enters the parallel channels above each layer of reaction plates or the bottom plate to be contacted and mixed with the gas. The gas containing the absorbed component enters the micro absorber 2 from the gas inlet end, is distributed into parallel channels on each layer of reaction plate or bottom plate, and leaves the micro absorber 2 from the gas-liquid mixture outlet end after being contacted and mixed with the absorbent.
Example 1:
every 1 ton of yellow phosphorus is used, the mass of oxygen is 1.2 tons of the mass of the yellow phosphorus, the hydrating agent is water or solutions with different P2O5 mass fractions, the mass of the water in the hydrating agent is 0.29 ton of the mass of the yellow phosphorus, the mass of the water for preparing the saturated soft water is 1 ton of the mass of the yellow phosphorus, and the consumption of the washing water is 0.29 ton of the mass of the yellow phosphorus.
The hydraulic radius of the parallel channel of the micro absorber 2 is 0.05mm, the radius of the dispersion hole is 0.01mm, the included angle between the axis of the dispersion hole and the axis of the parallel channel is 20 degrees, and the residence time of the materials is 1s.
Example 2:
every 1 ton of yellow phosphorus is used, the mass of oxygen is 2.4 tons of the mass of the yellow phosphorus, the hydrating agent is water or solutions with different P2O5 mass fractions, the mass of the water in the hydrating agent is 3 tons of the mass of the yellow phosphorus, the mass of the water for preparing the saturated soft water is 10 tons of the mass of the yellow phosphorus, and the consumption of the washing water is 3 tons of the mass of the yellow phosphorus.
The used micro absorber 2 has a parallel channel hydraulic radius of 5mm, a dispersion hole radius of 1mm, an included angle between the axis of the dispersion hole and the axis of the parallel channel of 55 DEG, and the retention time of the material of 30s
Example 3:
every 1 ton of yellow phosphorus is used, the mass of oxygen is 2.6 tons of the mass of the yellow phosphorus, the hydrating agent is water or solutions with different P2O5 mass fractions, the mass of the water in the hydrating agent is 6 tons of the mass of the yellow phosphorus, the mass of the water for preparing the saturated soft water is 20 tons of the mass of the yellow phosphorus, and the consumption of the washing water is 6 tons of the mass of the yellow phosphorus.
The hydraulic radius of the parallel channel of the micro absorber 2 is 10mm, the radius of the dispersion hole is 2mm, the included angle between the axis of the dispersion hole and the axis of the parallel channel is 90 degrees, and the retention time of the materials is 60s.
Through the tests of the embodiments 1, 2 and 3, the test data can have a better test structure, and the test data can meet the production requirement of hot phosphoric acid and is beneficial to recycling of reaction heat and combustion heat energy in the production process.
Claims (4)
1. A method for preparing phosphoric acid by a thermal method and recovering heat energy is characterized in that yellow phosphorus is contacted with an oxidant to generate combustion reaction to generate gas containing phosphorus pentoxide, and the gas containing phosphorus pentoxide is contacted with a hydrating agent to generate hydration reaction, and the method is characterized in that: the method uses a micro absorber to absorb heat of hydration reaction heat, the reaction heat is brought into a separation tank by a gas-liquid mixture after passing through the micro absorber (2), and the heat of the tail gas is returned firstlyThe recovery device and the concentrated phosphoric acid cooler respectively absorb the heat of the gas phase and the liquid phase, then neutralize the heat of the gas phase and the liquid phase, and finally convey the heat to an evaporation device of a yellow phosphorus boiler in a saturated soft water form for steam, so that the heat energy can be recovered while the phosphoric acid is prepared; the mass of oxygen in the oxidant is 1.2-2.6 times of that of yellow phosphorus, and the hydrating agent is water or different P 2 O 5 The mass fraction of the solution is 0.29-6 times of that of yellow phosphorus in the hydrating agent, and the mass of the water for preparing the saturated soft water is 1-20 times of that of the yellow phosphorus;
the gas containing phosphorus pentoxide contacts with the hydrating agent, and the hydrating agent is added once or added again after the first time, and is separated from the gas and the liquid at the downstream of the liquid phase;
the device comprises a yellow phosphorus boiler (1), wherein an outlet of the yellow phosphorus boiler (1) is connected with a gas inlet end of a micro absorber (2), an absorbent inlet and a gas-liquid mixture outlet are arranged on the micro absorber (2), the gas-liquid mixture outlet is connected with a separation tank (3), a gas phase outlet of the separation tank (3) is connected with a tail gas cooler (4), the tail gas cooler (4) is connected with a gas treatment device, a liquid phase outlet of the separation tank (3) is connected with a concentrated phosphoric acid cooler (6), the tail gas cooler (4) is provided with a soft water inlet and a soft water preheating outlet, the preheated soft water outlet is sequentially connected with a 85 phosphoric acid cooler (7) and the concentrated phosphoric acid cooler (6) through pipelines, and a saturated soft water outlet of the concentrated phosphoric acid cooler (6) is connected with a steam device of the yellow phosphorus boiler (1);
the micro absorber (2) comprises a bottom plate and a cover plate, wherein one reaction plate is arranged in the bottom plate and the cover plate, an absorbent inlet is formed in the corner of the cover plate, absorbent channels are formed in the corresponding positions of the reaction plate, parallel channels are uniformly distributed on the upper plate surfaces of the bottom plate and the reaction plate, a dispersion plate perpendicular to the direction of the parallel channels is arranged at the absorbent channels, dispersion holes are formed in the dispersion plate, grooves embedded in the dispersion plate are formed in the bottom of the reaction plate, a gas inlet is formed in the bottom plate on the same side as the absorbent channels, and a gas-liquid mixture outlet is formed in the reaction plate on one side far away from the absorbent channels.
2. The method for preparing phosphoric acid by thermal process and recovering heat energy according to claim 1, wherein: the tail gas heat recovery device comprises a tail gas cooler and an 85 phosphoric acid cooler, the gas absorbs heat through the tail gas cooler and then sends cooled tail gas to the tail gas scrubber for washing, the consumption of washing water is 0.29-6 times of the mass of yellow phosphorus, and the washed water is used for hydration reaction.
3. Device for the preparation of hot phosphoric acid and recovery of thermal energy according to the method of claim 1 or 2, comprising a yellow phosphorus boiler (1), characterized in that: the outlet of the yellow phosphorus boiler (1) is connected with the gas inlet end of the micro absorber (2), the micro absorber (2) is provided with an absorbent inlet and a gas-liquid mixture outlet, the gas-liquid mixture outlet is connected with a separation tank (3), the gas-phase outlet of the separation tank (3) is connected with a tail gas cooler (4), the tail gas cooler (4) is connected with a gas treatment device, the liquid-phase outlet of the separation tank (3) is connected with a concentrated phosphorus cooler (6), the tail gas cooler (4) is provided with a soft water inlet and a preheated soft water outlet, the preheated soft water outlet is sequentially connected with an 85 phosphorus cooler (7) and a concentrated phosphorus cooler (6) through pipelines, and the saturated soft water outlet of the concentrated phosphorus cooler (6) is connected with a steam device of the yellow phosphorus boiler (1);
the micro absorber (2) comprises a bottom plate and a cover plate, wherein one reaction plate is arranged in the bottom plate and the cover plate, an absorbent inlet is formed in the corner of the cover plate, absorbent channels are formed in the corresponding positions of the reaction plate, parallel channels are uniformly distributed on the upper plate surfaces of the bottom plate and the reaction plate, a dispersion plate perpendicular to the direction of the parallel channels is arranged at the absorbent channels, dispersion holes are formed in the dispersion plate, grooves embedded in the dispersion plate are formed in the bottom of the reaction plate, a gas inlet is formed in the bottom plate on the same side as the absorbent channels, and a gas-liquid mixture outlet is formed in the reaction plate on one side far away from the absorbent channels.
4. The apparatus for preparing phosphoric acid by thermal process and recovering heat energy according to claim 3, wherein: the hydraulic radius of the parallel channel is 0.05mm-10mm, the radius of the dispersion hole is 0.01mm-2mm, the included angle between the axis of the dispersion hole and the axis of the parallel channel is 20-90 degrees, and the retention time of the material is 1s-60s.
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| JPS5484890A (en) * | 1977-12-19 | 1979-07-06 | Kawasaki Heavy Ind Ltd | Apparatus for preparing phosphoric acid |
| CN101157449A (en) * | 2007-09-26 | 2008-04-09 | 云南常青树化工有限公司 | Kiln-way phosphoric acid absorbing defluorination method |
| CN101612510A (en) * | 2008-06-25 | 2009-12-30 | 中国科学院大连化学物理研究所 | A kind of absorption CO 2Micro-channel absorber |
| CN201942519U (en) * | 2010-03-02 | 2011-08-24 | 广西越洋化工有限责任公司 | Thermal energy recovery and utilization device in production of thermal phosphoric acid and production system of thermal energy recovery and utilization device |
| CN202430008U (en) * | 2011-12-23 | 2012-09-12 | 中国化学工程第七建设有限公司 | Device for phosphorus pentoxide production and thermal energy recovery |
| CN105080307A (en) * | 2014-05-12 | 2015-11-25 | 陈汇宏 | Desulfurization and denitrification method for tail gas, used equipment and product application thereof |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| JPS5484890A (en) * | 1977-12-19 | 1979-07-06 | Kawasaki Heavy Ind Ltd | Apparatus for preparing phosphoric acid |
| CN101157449A (en) * | 2007-09-26 | 2008-04-09 | 云南常青树化工有限公司 | Kiln-way phosphoric acid absorbing defluorination method |
| CN101612510A (en) * | 2008-06-25 | 2009-12-30 | 中国科学院大连化学物理研究所 | A kind of absorption CO 2Micro-channel absorber |
| CN201942519U (en) * | 2010-03-02 | 2011-08-24 | 广西越洋化工有限责任公司 | Thermal energy recovery and utilization device in production of thermal phosphoric acid and production system of thermal energy recovery and utilization device |
| CN202430008U (en) * | 2011-12-23 | 2012-09-12 | 中国化学工程第七建设有限公司 | Device for phosphorus pentoxide production and thermal energy recovery |
| CN105080307A (en) * | 2014-05-12 | 2015-11-25 | 陈汇宏 | Desulfurization and denitrification method for tail gas, used equipment and product application thereof |
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