CN112279226A - Device and method for improving quality of dilute nitric acid product - Google Patents
Device and method for improving quality of dilute nitric acid product Download PDFInfo
- Publication number
- CN112279226A CN112279226A CN202011404815.8A CN202011404815A CN112279226A CN 112279226 A CN112279226 A CN 112279226A CN 202011404815 A CN202011404815 A CN 202011404815A CN 112279226 A CN112279226 A CN 112279226A
- Authority
- CN
- China
- Prior art keywords
- air
- pipeline
- tower
- gas
- nitrogen oxide
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 title claims abstract description 68
- 229910017604 nitric acid Inorganic materials 0.000 title claims abstract description 68
- 238000000034 method Methods 0.000 title claims abstract description 12
- MWUXSHHQAYIFBG-UHFFFAOYSA-N Nitric oxide Chemical compound O=[N] MWUXSHHQAYIFBG-UHFFFAOYSA-N 0.000 claims abstract description 281
- 239000007789 gas Substances 0.000 claims abstract description 112
- 238000010521 absorption reaction Methods 0.000 claims abstract description 95
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 claims abstract description 60
- 238000007254 oxidation reaction Methods 0.000 claims abstract description 59
- 230000003647 oxidation Effects 0.000 claims abstract description 57
- 239000002253 acid Substances 0.000 claims abstract description 53
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 50
- 238000006243 chemical reaction Methods 0.000 claims abstract description 43
- 229910021529 ammonia Inorganic materials 0.000 claims abstract description 33
- 238000004061 bleaching Methods 0.000 claims abstract description 27
- 238000001816 cooling Methods 0.000 claims abstract description 25
- 230000003584 silencer Effects 0.000 claims abstract description 12
- 230000006835 compression Effects 0.000 claims abstract description 7
- 238000007906 compression Methods 0.000 claims abstract description 7
- 239000007788 liquid Substances 0.000 claims description 38
- 239000003054 catalyst Substances 0.000 claims description 35
- 230000001105 regulatory effect Effects 0.000 claims description 34
- 238000001914 filtration Methods 0.000 claims description 17
- 239000002245 particle Substances 0.000 claims description 10
- 239000012071 phase Substances 0.000 claims description 9
- 230000007246 mechanism Effects 0.000 claims description 8
- 239000002918 waste heat Substances 0.000 claims description 8
- 230000009471 action Effects 0.000 claims description 7
- 239000000498 cooling water Substances 0.000 claims description 7
- 239000007791 liquid phase Substances 0.000 claims description 7
- 238000004519 manufacturing process Methods 0.000 claims description 7
- 230000003197 catalytic effect Effects 0.000 claims description 5
- 238000002156 mixing Methods 0.000 claims description 5
- 239000007787 solid Substances 0.000 claims description 5
- 230000001276 controlling effect Effects 0.000 claims description 4
- PXXKQOPKNFECSZ-UHFFFAOYSA-N platinum rhodium Chemical compound [Rh].[Pt] PXXKQOPKNFECSZ-UHFFFAOYSA-N 0.000 claims description 4
- 230000008569 process Effects 0.000 claims description 4
- 238000005507 spraying Methods 0.000 claims description 3
- 238000007599 discharging Methods 0.000 claims description 2
- 239000012530 fluid Substances 0.000 claims description 2
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 claims 2
- 229910052757 nitrogen Inorganic materials 0.000 claims 1
- 239000007921 spray Substances 0.000 description 9
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical compound [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 description 8
- WNLRTRBMVRJNCN-UHFFFAOYSA-N adipic acid Chemical compound OC(=O)CCCCC(O)=O WNLRTRBMVRJNCN-UHFFFAOYSA-N 0.000 description 6
- 239000004744 fabric Substances 0.000 description 5
- 229910052697 platinum Inorganic materials 0.000 description 4
- 238000000926 separation method Methods 0.000 description 4
- 238000003466 welding Methods 0.000 description 4
- 235000011037 adipic acid Nutrition 0.000 description 3
- 239000001361 adipic acid Substances 0.000 description 3
- 230000006872 improvement Effects 0.000 description 3
- 239000003595 mist Substances 0.000 description 3
- 239000000203 mixture Substances 0.000 description 3
- 238000011084 recovery Methods 0.000 description 3
- MGWGWNFMUOTEHG-UHFFFAOYSA-N 4-(3,5-dimethylphenyl)-1,3-thiazol-2-amine Chemical compound CC1=CC(C)=CC(C=2N=C(N)SC=2)=C1 MGWGWNFMUOTEHG-UHFFFAOYSA-N 0.000 description 2
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 2
- 229910000975 Carbon steel Inorganic materials 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 2
- 229910052799 carbon Inorganic materials 0.000 description 2
- 239000010962 carbon steel Substances 0.000 description 2
- 238000004140 cleaning Methods 0.000 description 2
- 238000005260 corrosion Methods 0.000 description 2
- 230000007797 corrosion Effects 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 239000000428 dust Substances 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 230000008014 freezing Effects 0.000 description 2
- 238000007710 freezing Methods 0.000 description 2
- 230000008676 import Effects 0.000 description 2
- JCXJVPUVTGWSNB-UHFFFAOYSA-N nitrogen dioxide Inorganic materials O=[N]=O JCXJVPUVTGWSNB-UHFFFAOYSA-N 0.000 description 2
- 239000002994 raw material Substances 0.000 description 2
- 239000010935 stainless steel Substances 0.000 description 2
- 229910001220 stainless steel Inorganic materials 0.000 description 2
- PAWQVTBBRAZDMG-UHFFFAOYSA-N 2-(3-bromo-2-fluorophenyl)acetic acid Chemical compound OC(=O)CC1=CC=CC(Br)=C1F PAWQVTBBRAZDMG-UHFFFAOYSA-N 0.000 description 1
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 1
- 229910000629 Rh alloy Inorganic materials 0.000 description 1
- 150000003863 ammonium salts Chemical class 0.000 description 1
- 238000004458 analytical method Methods 0.000 description 1
- 239000007844 bleaching agent Substances 0.000 description 1
- 239000000919 ceramic Substances 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 229910052802 copper Inorganic materials 0.000 description 1
- 239000010949 copper Substances 0.000 description 1
- 238000002425 crystallisation Methods 0.000 description 1
- 230000008025 crystallization Effects 0.000 description 1
- HPXRVTGHNJAIIH-UHFFFAOYSA-N cyclohexanol Chemical compound OC1CCCCC1 HPXRVTGHNJAIIH-UHFFFAOYSA-N 0.000 description 1
- 230000008021 deposition Effects 0.000 description 1
- 238000004090 dissolution Methods 0.000 description 1
- 238000009826 distribution Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 239000003365 glass fiber Substances 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 238000013021 overheating Methods 0.000 description 1
- 239000011087 paperboard Substances 0.000 description 1
- 238000005096 rolling process Methods 0.000 description 1
- 230000008719 thickening Effects 0.000 description 1
- 230000009466 transformation Effects 0.000 description 1
- 229910052720 vanadium Inorganic materials 0.000 description 1
- LEONUFNNVUYDNQ-UHFFFAOYSA-N vanadium atom Chemical compound [V] LEONUFNNVUYDNQ-UHFFFAOYSA-N 0.000 description 1
Images
Classifications
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
- C01B21/00—Nitrogen; Compounds thereof
- C01B21/20—Nitrogen oxides; Oxyacids of nitrogen; Salts thereof
- C01B21/38—Nitric acid
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D46/00—Filters or filtering processes specially modified for separating dispersed particles from gases or vapours
- B01D46/56—Filters or filtering processes specially modified for separating dispersed particles from gases or vapours with multiple filtering elements, characterised by their mutual disposition
- B01D46/62—Filters or filtering processes specially modified for separating dispersed particles from gases or vapours with multiple filtering elements, characterised by their mutual disposition connected in series
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
- B01D53/14—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols by absorption
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
- B01D53/14—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols by absorption
- B01D53/18—Absorbing units; Liquid distributors therefor
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
- B01D53/34—Chemical or biological purification of waste gases
- B01D53/74—General processes for purification of waste gases; Apparatus or devices specially adapted therefor
- B01D53/86—Catalytic processes
- B01D53/8621—Removing nitrogen compounds
- B01D53/8634—Ammonia
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
- C01B21/00—Nitrogen; Compounds thereof
- C01B21/20—Nitrogen oxides; Oxyacids of nitrogen; Salts thereof
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
- C01B21/00—Nitrogen; Compounds thereof
- C01B21/20—Nitrogen oxides; Oxyacids of nitrogen; Salts thereof
- C01B21/24—Nitric oxide (NO)
- C01B21/26—Preparation by catalytic or non-catalytic oxidation of ammonia
- C01B21/265—Preparation by catalytic or non-catalytic oxidation of ammonia characterised by the catalyst
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
- C01B21/00—Nitrogen; Compounds thereof
- C01B21/20—Nitrogen oxides; Oxyacids of nitrogen; Salts thereof
- C01B21/38—Nitric acid
- C01B21/40—Preparation by absorption of oxides of nitrogen
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2257/00—Components to be removed
- B01D2257/40—Nitrogen compounds
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2257/00—Components to be removed
- B01D2257/40—Nitrogen compounds
- B01D2257/406—Ammonia
-
- 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
- Y02P20/129—Energy recovery, e.g. by cogeneration, H2recovery or pressure recovery turbines
Landscapes
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Engineering & Computer Science (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Inorganic Chemistry (AREA)
- Oil, Petroleum & Natural Gas (AREA)
- Analytical Chemistry (AREA)
- General Chemical & Material Sciences (AREA)
- Environmental & Geological Engineering (AREA)
- Materials Engineering (AREA)
- Biomedical Technology (AREA)
- Health & Medical Sciences (AREA)
- Treating Waste Gases (AREA)
Abstract
The invention discloses a device and a method for improving the quality of a dilute nitric acid product. The air compression system comprises an air inlet silencer, an air preheater, an air filter and an air compressor, and the oxidation system comprises an ammonia gas filter, an ammonia gas-air mixer and an oxidation furnace; the cooling system comprises a high-temperature gas-gas heat exchanger, an economizer, a low-pressure reaction water cooler, a nitrogen oxide separator, a nitrogen oxide compressor, a tail gas preheater and a high-pressure reaction water cooler which are sequentially connected through pipelines, the bottom of the nitrogen oxide separator is connected with a dilute acid pump through a pipeline, the absorption system comprises an absorption tower, a bleaching tower and a finished product acid cooler which are sequentially connected through pipelines, and the lower part of the bleaching tower is connected with a secondary air cooler through a pipeline.
Description
Technical Field
The invention belongs to the technical field of nitric acid production, and particularly relates to a device and a method for improving the quality of a dilute nitric acid product.
Background
Adipic acid of our company is obtained by carrying out oxidation reaction on cyclohexanol, copper and vanadium under the action of a catalyst and nitric acid, and carrying out crystallization, dissolution, decoloration, thickening, centrifugal separation and other processes on the solution after the reaction is finished. In order to improve the quality of adipic acid, the quality of nitric acid, which is a raw material for producing adipic acid, needs to be preferentially improved.
At present, the dilute nitric acid production process in China mostly adopts a double-pressurization method nitric acid production process, ammonia oxidation is carried out at medium pressure, and nitrogen dioxide absorption is carried out at high pressure. Liquid ammonia is filtered, evaporated, heated and mixed with excessive compressed air to enter an oxidation furnace, nitric oxide is generated under the action of a platinum catalyst, the nitric oxide and the excessive compressed air react to generate nitrogen dioxide in the process of cooling through a heat exchanger, and simultaneously react with product water of an ammoxidation reaction to generate condensed acid, after a gas-liquid mixture enters a nitrogen oxide separator to be subjected to gas-liquid separation, a gas phase enters a nitrogen oxide compressor to be pressurized, the gas phase is cooled through a series of heat exchangers and enters the bottom of an absorption tower to be in reverse contact with desalted water at the top of the absorption tower on a tower plate to generate a dilute nitric acid product, and the dilute nitric acid enters a bleaching tower to be subjected to secondary air denitration to generate qualified dilute nitric acid.
Because the traditional filter has low filtration precision, suspended particles in air enter an oxidation furnace to cause the activity of a platinum mesh catalyst to be reduced, the conversion rate of ammonia is reduced, the water content in the raw material gas of the nitric acid process is high, the traditional nitrogen oxide separator is difficult to capture submicron fog particles in the air flow, the performance of a nitrogen oxide compressor is limited, and the yield and the concentration of dilute nitric acid are low.
Disclosure of Invention
In order to overcome the problems in the prior art, the invention aims to provide a device and a method for improving the quality of a nitric acid product. The device and the method for improving the quality of the nitric acid product can effectively filter suspended particles in air and absorb water in the air, keep a catalyst bed layer clean and pollution-free, protect the activity of the catalyst, improve the conversion rate of ammonia and effectively improve the capacity and the concentration of nitric acid.
In order to achieve the purpose, the technical scheme adopted by the invention is as follows:
a device for improving the quality of dilute nitric acid products comprises an air compression system, an oxidation system, a cooling system and an absorption system, wherein the air compression system comprises an air inlet silencer, an air preheater, an air filter and an air compressor, the oxidation system comprises an ammonia-air mixer and an oxidation furnace, the cooling system comprises a high-temperature gas-gas heat exchanger, an economizer, a low-pressure reaction water cooler, a nitrogen oxide separator, a nitrogen oxide compressor, a tail gas preheater and a high-pressure reaction water cooler which are sequentially connected through pipelines, the absorption system comprises an absorption tower, a bleaching tower, a finished acid cooler and a secondary air cooler which are sequentially connected through pipelines, the air inlet silencer, the air preheater and the air filter are sequentially connected, the air filter is connected with the air compressor through pipelines, and a primary air pipeline and a secondary air pipeline are arranged at the tail end branch of a main pipeline at the outlet of the air compressor, the primary air pipeline is connected with the ammonia-air mixer, the secondary air pipeline is connected with the secondary air cooler, the upper part of the oxidation furnace is provided with a catalyst basket, the lower part of the oxidation furnace is sequentially provided with a steam superheater and a waste heat boiler, a plurality of catalyst layers and a plurality of supporting nets are arranged in the oxidation furnace, cooling coils are arranged on tower plates of the absorption tower, a plurality of baffle plates are further arranged on tower plates of the absorption tower, so that liquid flows in a double S shape in the horizontal direction, a plurality of overflow pipes are arranged on each tower plate, and the positions of the overflow pipes on the tower plates of the odd number layers and the tower plates of the even number layers are in mirror symmetry with each other.
Further, the ammonia-air mixer is provided with two paths of inlets, one path of inlets is connected with an outlet of the air compressor through a pipeline, the other path of inlets is a gas-ammonia inlet pipeline, the pipeline is provided with a gas-ammonia flow regulating valve, a pressure gauge, a remote thermometer, a flow meter and a gas-ammonia check valve, a main pipeline at the outlet of the air compressor is provided with the pressure gauge and the remote thermometer, a primary air check valve, a primary air flow regulating valve, the pressure gauge, the remote thermometer and the flow meter are arranged on the primary air pipeline, a secondary air check valve, the flow meter and a secondary air flow regulating valve are arranged on the secondary air pipeline, the outlet of the ammonia-air mixer is connected with the top of the oxidation furnace through the pipeline, the pipeline is provided with the remote thermometer and an expansion joint, and the oxidation furnace: the uppermost layer of the support net supports 6 catalyst layers, the rest support nets support one catalyst layer each layer, and the lowermost layer of the support net is fixed in the catalyst frame through Raschig rings.
Further, the nitrogen oxide separator is provided with a gas phase outlet and a liquid phase outlet, the gas phase outlet is connected with the nitrogen oxide compressor through a pipeline, the liquid phase outlet is connected with the dilute acid pump through a pipeline, the tail end of an outlet pipeline of the dilute acid pump is divided into five paths and is respectively connected with the 7 th to 11 th tower plates of the absorption tower, the high-pressure reaction water cooler is provided with a gas outlet and a liquid outlet, the gas outlet is connected with the lower part of the first layer tower plate of the absorption tower through a pipeline, and the liquid outlet is connected with the 3 rd tower plate of the absorption tower through a pipeline.
Further, the bleaching tower is provided with a secondary air inlet, a gas outlet, a dilute nitric acid inlet and a dilute nitric acid outlet, the secondary air inlet is connected with an outlet of a secondary air cooler through a pipeline, the gas outlet is provided with an output pipeline, the output pipeline is communicated with a pipeline between the low-pressure reaction water cooler and the nitrogen oxide separator, the dilute nitric acid inlet is connected with a bottom outlet of the absorption tower through a pipeline, and the dilute nitric acid outlet is connected with a finished product acid cooler through a pipeline.
Further, the upper portion in the nitrogen oxide separator is equipped with the silk screen demister, and the below of silk screen demister is equipped with the blade separator, and the silk screen demister is a cylinder of constituteing by the lateral wall and the roof of locating the lateral wall top, and the upper portion of silk screen demister, the top and the below of blade separator all are equipped with and spray the mechanism, it links to each other with the spray piping to spray the mechanism.
Furthermore, a tail gas discharge pipeline is arranged at the top of the absorption tower, a demister is arranged above the uppermost tower plate in the absorption tower, a downcomer is arranged at the bottom of an overflow pipe on the lowermost tower plate of the absorption tower so as to send liquid to the bottom of the absorption tower, and a finished acid delivery pipeline is arranged at the bottom of the finished acid cooler.
Furthermore, the tower plates of the absorption tower are 32 layers, two groups of cooling coil pipes are arranged on the rest layers except 29 and 31 layers, the downcomer is obliquely arranged, the height of the overflow pipe protruding out of the tower plates is 3-5 cm, and the distance between every two adjacent tower plates is 50-1 m.
Further, the air filter is a three-stage filter, the primary filtering precision is 5 μm, the secondary filtering precision is 3 μm, and the third filtering precision is 0.5 μm.
Wherein, a pressure gauge is arranged between each stage of the air filter, a remote thermometer is arranged on a pipeline between the oxidation furnace and the high-temperature gas-gas heat exchanger, a remote thermometer is arranged on an inlet pipeline of the nitrogen oxide separator, a remote thermometer and a liquid level meter are arranged on a main body of the nitrogen oxide separator, and a condensed acid regulating valve is arranged on an outlet pipeline of the dilute acid pump so as to realize automatic regulation according to a liquid level control index of the nitrogen oxide separator; be equipped with compressed nitrogen oxide check valve and pressure gauge on the pipeline between nitrogen oxide compressor and the tail gas preheater, the pipeline is equipped with the teletransmission thermometer between high-pressure reaction water cooler gas outlet and the absorption tower, set up the teletransmission thermometer on the pipeline between secondary air cooler to the bleaching tower, be equipped with the teletransmission thermometer on the tail gas discharge pipeline at absorption tower top, be equipped with the liquid level control valve on the pipeline between absorption tower and the bleaching tower, be equipped with teletransmission thermometer and finished product acidizing fluid level regulating valve on the finished product acid outward transport pipeline, the teletransmission thermometer, the teletransmission pressure gauge, the teletransmission flowmeter, the DCS system is all even gone into to the governing valve.
The method for producing the dilute nitric acid by using the device for improving the quality of the dilute nitric acid product comprises the following steps:
(1) air uniformly enters an air filter through an air silencer and an air preheater to be subjected to three-stage filtration, solid particles larger than 0.5 mu m in the air are filtered out, moisture in the air is removed, the filtered air is compressed by an air compressor and then is divided into two paths, one path of the filtered air is primary air which passes through a primary air check valve, a primary air flow regulating valve enters an ammonia-air mixer, and the other path of the filtered air is secondary air which passes through a secondary air check valve, and a secondary air flow regulating valve enters a secondary air cooler;
(2) uniformly mixing primary air and gas ammonia in an ammonia-air mixer, enabling the gas ammonia to enter the ammonia-air mixer through a gas ammonia flow regulating valve and a check valve, controlling the ammonia-air ratio to be 9-9.5%, enabling the ammonia-air mixed gas to enter an oxidation furnace, reacting under the catalytic oxidation action of a platinum-rhodium catalyst to generate nitric oxide, and performing heat recovery on high-temperature nitric oxide in the oxidation furnace through a steam superheater and a waste heat boiler;
(3) the high-temperature nitrogen oxide from the oxidation furnace is subjected to heat exchange through a high-temperature gas-gas heat exchanger, an economizer and a low-pressure reaction water cooler, the temperature is reduced to 45 ℃ and then enters a nitrogen oxide separator, a dilute acid pump is connected to the bottom of the nitrogen oxide separator to continuously send condensed acid to tower plates with corresponding concentration gradients of the absorption tower, the nitrogen oxide gas dried at the top enters a nitrogen oxide compressor for pressurization, and the pressurized nitrogen oxide gas passes through a tail gas preheater and is cooled by a high-pressure reaction water cooler and then enters the lower part of a first-layer tower plate of the absorption tower;
(4) condensed acid accumulated in a high-pressure reaction water cooler is discharged from the bottom and is conveyed to a 3 rd layer of tower plate of an absorption tower through a pipeline, tower gas entering the tower and absorption water from the top of the absorption tower are in contact reaction on the tower plate to generate dilute nitric acid, the absorption tower adopts a sectional cooling structure, 1-11 layers adopt circulating cooling water at 32 ℃ for heat exchange, 12-27 layers adopt low-temperature cooling water at 20 ℃ for heat exchange, 28-32 layers adopt freezing water at 12 ℃ for heat exchange, liquid flows in a double-S shape on each layer of the absorption tower and flows in an S shape between the layers, the dilute nitric acid at the bottom of the absorption tower is conveyed to the top of a bleaching tower through a liquid level regulating valve, secondary air enters from the lower part of a first layer of pedal of the bleaching tower and is in countercurrent contact with the first layer of pedal to strip nitric acid gas dissolved in nitric acid products, and the bleaching2Mixing the gas, finally entering a nitrogen oxide compressor to be pressurized, discharging qualified dilute nitric acid products from the bottom of the bleaching tower, cooling the dilute nitric acid products to 50 ℃ through a finished product acid cooler, and delivering the dilute nitric acid products outside through a finished product acid liquid level regulating valve.
Preferably, the volume ratio of the primary air to the secondary air is 12:1, the temperature of the ammonia-air mixed gas at the inlet of the oxidation furnace is 180 ℃, the reaction temperature of the oxidation furnace is 830 ℃, and the temperature of nitrogen oxides at the outlet is 450 ℃; the outlet pressure of the nitrogen oxide compressor is 0.9MPa, the temperature of the nitrogen oxide at the inlet of the absorption tower is 45 ℃, the temperature of the absorption water is 18 ℃, and the outlet temperature of the tail gas at the top of the absorption tower is 25 ℃.
In the invention, the air filter adopts a brickyard type structure. Indoor three-stage dry filter: the first stage is of a rolling curtain type, when the pressure difference is high, the filter cloth can be manually updated, the second stage and the third stage are fixed frame types, fine glass fiber paperboards are adopted to be processed into a pocket type and a square box type and are arranged on the fixed frame, a covering layer is added on the first stage filter cloth, the filtering precision is 5 micrometers, the precision of the second stage filter bag is 3 micrometers, and the precision of the third stage filter element is 0.5 micrometer. Can filter out 0.5 micron dust, and has small resistance and high efficiency up to 99%. In order to prevent the outdoor temperature from being too low in winter, an air preheater is also arranged at an air inlet, and a differential pressure gauge is arranged between each stage.
The ammonia gas is filtered and purified by a gas ammonia filter, enters an ammonia-air mixer, is fully mixed with primary air, enters an oxidation furnace, is subjected to ammonia oxidation reaction under the action of a catalyst to generate NO gas and release a large amount of heat, when hot gas flows through a steam superheater and a waste heat boiler, part of heat is recovered, and NO at an equipment outlet is recoveredXThe gas temperature is reduced to 450 ℃. NO leaving the oxidation oven as the temperature of the nitrogen oxide gas decreasesXThe gas begins to be oxidized and enters a high-temperature gas-gas heat exchanger, an economizer and a low-pressure reaction water cooler in sequence, and NO is generated in the low-pressure reaction water cooler2And a small amount of dilute nitric acid (-28%). The acid gas mixture is separated by a nitrogen oxide separator, and NO is obtained after separationXMixing the gas with secondary air from a bleaching tower, pressurizing the mixed gas to 0.9MPa by a nitrogen oxide compressor, sending the mixed gas into a tail gas preheater and a high-pressure reaction water cooler, and finally entering the lower part of a first-layer tower plate of an absorption tower.
Preferably, each set of cooling coils on the absorption tower is clamped and bolted against vibration. The tower plate bracket and the tower plate are fixed by movable bolts, so that the welding deformation and the stress corrosion of the tower body can be avoided, and the levelness of the installed tower plate is within the range of +/-2 mm. All welding parts in the tower body and the tower are made of ultra-low carbon stainless steel 304L type, and the others are 304 type. The tower skirt is made of carbon steel.
The improvement point of the application comprises (1) adding a covering layer on the primary filtration of the air filter, wherein the precision is from 10 mu m to 5 mu m, the precision of a secondary filter bag is changed from 5 mu m to 3 mu m, and the precision of a tertiary filter element is changed from 1.0 mu m to 0.5 mu m;
(2) the catalyst in the oxidation furnace is changed from seven layers of platinum-rhodium alloy nets to 11 layers of multifunctional catalytic nets,
(3) controlling the ammonia-air ratio to be 9.3%, the temperature of the ammonia-air mixed gas at the inlet of the oxidation furnace to be 180 ℃, and the reaction temperature of the oxidation furnace to be 830 ℃;
(4) controlling the pressure of the pressurized nitrogen oxide gas to be 0.9MPa, the temperature of the nitrogen oxide at the inlet of the absorption tower to be 45 ℃, the temperature of the absorption water to be 18 ℃, and the temperature of the tail gas at the top of the absorption tower to be 25 ℃; cooling water coils are arranged on tower plates of each layer of the absorption tower and are used for absorbing reaction heat;
(5) the method for improving the separating capacity of the nitrogen oxide separator comprises the step of replacing the folded plate type separator with a novel efficient separator consisting of a novel blade separator and a wire mesh demister.
Compared with the prior art, the invention has the beneficial effects that: the high-precision filtering element can filter out 0.5 micron dust, has small resistance and high efficiency up to 99 percent, and effectively filters suspended particles and water in the air; the catalyst adopts a novel multifunctional catalytic net, so that the active area of the platinum net is increased, and the conversion rate of ammonia is improved; the nitrogen oxide separator effectively captures submicron mist particles which are difficult to capture in airflow, the mist removal precision is less than 1 mu m, the mist removal efficiency is as high as 99.99 percent, the performance of a nitrogen oxide compressor is improved, the air inlet pressure of an absorption tower is improved, and the absorption of nitrogen oxides is facilitated. In conclusion, the quality of the nitric acid is effectively improved, and the yield and the concentration of the nitric acid are improved through technical transformation.
Drawings
FIG. 1 is a schematic structural diagram of an apparatus for improving the quality of a dilute nitric acid product according to the present invention;
FIG. 2 is a schematic view of the construction of the oxidation furnace, and the distribution of the catalyst and support screen;
FIG. 3 is a schematic view of the structure of an absorption column;
FIG. 4 is a schematic diagram of a nitrogen oxide separator;
in the figure: 1 is an air inlet silencer, 2 is an air preheater, 3 is an air filter, 4 is an air compressor, 5 is an ammonia-air mixer, 6 is an oxidation furnace, 7 is a high-temperature gas-gas heat exchanger, 8 is an economizer, 9 is a low-pressure reaction water cooler, 10 is a nitrogen oxide separator, 11 is a nitrogen oxide compressor, 12 is a tail gas preheater, 13 is a high-pressure reaction water cooler, 14 is an absorption tower, 15 is a bleaching tower, 16 is a secondary air cooler, 17 is a catalyst, 18 is a steam superheater, 19 is a waste heat boiler, 20 is a finished product acid cooler, 22, a primary air flow regulating valve, 23, a liquid level regulating valve, 21, a gas-ammonia flow regulating valve, 24, a finished product acid liquid level regulating valve, 25, 26 is a condensed acid regulating valve, 27, a gas-ammonia check valve, 29, a primary air check valve, 39, a secondary air check valve, 47 is a check valve for compressing nitrogen oxide, 30, 31, 34, 36 and 52 are pressure gauges, 28, 32, 35, 37, 41, 43, 44, 45, 49, 50, 51 and 53 are telemetering thermometers, 33, 38, 40, 54, 55 and 56 are flow meters, 42 is an expansion joint, 46 is a liquid level meter, 48 is a dilute acid pump, 101 is a wire mesh demister, 102 is a blade separator, 103 is a spraying mechanism, 141 is a demister, 142 is an overflow pipe, 143 is a tower plate, 144 is a downcomer, 145 is a baffle plate, 146 is a manhole, 147 is a water supply pipeline of a cooling coil, 148 is a water return pipeline of the cooling coil, 171 is a catalyst layer, 172 is a supporting net.
Detailed Description
The invention is further illustrated, but not limited, by the following examples and the accompanying drawings.
Example 1
An apparatus for improving the quality of a dilute nitric acid product, as shown in fig. 1 to 4, comprises an air compression system, an oxidation system, a cooling system and an absorption system. The air compression system comprises an air inlet silencer 1, an air preheater 2, an air filter 3 and an air compressor 4, the oxidation system comprises an ammonia-air mixer 5 and an oxidation furnace 6, the cooling system comprises a high-temperature gas-gas heat exchanger 7, an economizer 8, a low-pressure reaction water cooler 9, a nitrogen oxide separator 10, a nitrogen oxide compressor 11, a tail gas preheater 12 and a high-pressure reaction water cooler 13 which are sequentially connected through pipelines, and the absorption system comprises an absorption tower 14, a bleaching tower 15, a finished product acid cooler 20 and a secondary air cooler 16 which are sequentially connected through pipelines.
The air inlet silencer 1, the air preheater 2 and the air filter 3 are sequentially connected, the air filter 3 is connected with the air compressor 4 through a pipeline, a primary air pipeline and a secondary air pipeline are arranged at the tail end branch of a main pipeline at the outlet of the air compressor 4, the primary air pipeline is connected with the ammonia-air mixer 5, the secondary air pipeline is connected with the secondary air cooler 16, filtered dry and clean air enters the air compressor 4 through the pipeline, the outlet is divided into two paths, one path is connected with the ammonia-air mixer 5 of the oxidation system through the pipeline, and the other path is connected with the secondary air cooler 16 of the absorption system through the pipeline. Pressure gauges 30 are arranged among the stages of the air inlet filter 3, a remote thermometer 28 is arranged on an inlet pipeline of the air compressor 4, a remote thermometer 35 and a pressure gauge 34 are arranged on an outlet main pipeline of the air compressor 4, a primary air check valve 29, a primary air flow regulating valve 22, a pressure gauge 36, a remote thermometer 37 and a flow meter 38 are sequentially arranged on a primary air pipeline, and a secondary air check valve 39, a flow meter 40 and a secondary air flow regulating valve 25 are sequentially arranged on a secondary air pipeline.
The ammonia-air mixer 5 is provided with two paths of inlets, one path is connected with the outlet of the air compressor 4 through a pipeline, the other path is a gas ammonia inlet pipeline, and the gas ammonia inlet pipeline is sequentially provided with a gas ammonia flow regulating valve 21, a pressure gauge 31, a remote thermometer 32, a flow meter 33 and a gas ammonia check valve 27. The air can uniformly pass through the air filter 3 through the air silencer 1, the air filter is of a three-stage filtering structure, the first stage is filter cloth, the second stage is a cloth bag type filter capable of filtering solid particles larger than 3 microns in the air, and the third stage adopts a filtering square box capable of filtering solid particles larger than 0.5 microns in the air and removing moisture in the air.
The outlet of the ammonia-air mixer 5 is connected with the top of the oxidation furnace 6 through a pipeline, as shown in fig. 2, the upper part of the oxidation furnace 6 is provided with a catalyst basket, the lower part is sequentially provided with a steam superheater 18 and a waste heat boiler 19, the oxidation furnace 6 is internally provided with 11 layers of catalyst layers 171 and 6 layers of supporting nets 172, the bottom of the supporting net 172 at the lowest layer is a ceramic raschig ring, the raschig ring is arranged in the catalyst basket, the catalyst frame is directly supported on the overheating coil pipe of the oxidation furnace 6, and the catalyst layers 171 and the supporting nets 172 in the oxidation furnace 6 are distributed as follows: the uppermost layer of support net 172 supports 6 catalyst layers 171, and each layer of the rest support nets 172 supports one catalyst layer 171 for supporting and isolating the catalyst 17, and can play a role in platinum recovery. A remote thermometer 41 and an expansion joint 42 are arranged on a pipeline between the ammonia-air mixer 5 and the oxidation furnace 6.
A remote thermometer 43 is arranged on a pipeline between the oxidation furnace 6 and the high-temperature gas-gas heat exchanger 7. The pipeline between the low-pressure reaction water cooler 9 and the nitrogen oxide separator 10 is provided with a remote thermometer 44, the nitrogen oxide separator 10 is provided with a remote thermometer 45 and a liquid level meter 46, the top of the nitrogen oxide separator 10 is provided with a gas phase outlet, the bottom of the nitrogen oxide separator 10 is provided with a liquid phase outlet, the gas phase outlet is connected with the nitrogen oxide compressor 11 through a pipeline, the liquid phase outlet is connected with a dilute acid pump 48 through a pipeline, an outlet pipeline of the dilute acid pump 48 is provided with a condensed acid regulating valve 26, the tail end of the outlet pipeline of the dilute acid pump 48 is divided into five paths and is respectively connected with the 7 th to 11 th tower plates of the absorption tower 14, the high-pressure reaction water cooler 13 is provided with a gas outlet and a liquid outlet, the gas outlet is connected with the lower part of the first layer tower plate of the absorption tower 14 through a pipeline, the liquid outlet is connected with the 3 rd tower plate of the absorption tower.
A compressed nitrogen oxide check valve 47 and a pressure gauge 52 are arranged on a pipeline between the nitrogen oxide compressor 11 and the tail gas preheater 12.
Nitrogen oxide separator 10 has adopted advanced separation technology and separating element, and upper portion in nitrogen oxide separator 10 is equipped with wire mesh demister 101, and the below of wire mesh demister 101 is equipped with vane separator 102, and wire mesh demister 101 is a cylinder of constituteing by the lateral wall and the roof of locating the lateral wall top, and the upper portion of wire mesh demister 101, the top and the below of vane separator 102 all are equipped with sprays mechanism 103, it links to each other with the spray line to spray mechanism 103, and the spray line entrance that spray mechanism 103 on wire mesh demister 101 upper portion is connected is equipped with flowmeter 54, and the spray line entrance that is connected of mechanism 103 is sprayed to the top of vane separator 102 and below is equipped with flowmeter 55 and flowmeter 56. The wire mesh demister 101 coagulates acid liquid through the action of collision and the like, so that the blade separator 102 can intercept the acid liquid conveniently, and an attachment site is provided for ammonium nitrate deposition; the third part is an online cleaning system, and the blade separator 102 and the wire mesh demister 101 are sprayed and cleaned under the condition that the operation of the equipment is not influenced, so that the purposes of dissolving ammonium salt and cleaning elements are achieved. Defogging efficiency: 99.99 percent.
Be equipped with liquid level control valve 23 on the pipeline between absorption tower 14 and bleaching tower 15, bleaching tower 15 is equipped with secondary air inlet, gas outlet, dilute nitric acid import and dilute nitric acid export, secondary air inlet is connected through the pipeline with secondary air cooler 16's export, gas outlet is equipped with the output pipeline, output pipeline and low pressure reaction water cooler 9 communicate on the pipeline between nitrogen oxide separator 10, dilute nitric acid import links to each other through the bottom export of pipeline and absorption tower 14, dilute nitric acid export is connected with finished product acid cooler 20 through the pipeline. A remote thermometer 50 is provided in the conduit between bleach tower 15 and secondary air cooler 16. The bottom of the finished acid cooler 20 is provided with a finished acid delivery pipeline, and the finished acid delivery pipeline is provided with a remote thermometer 51 and a finished acid liquid level regulating valve 24.
32 tower plates 143 of the absorption tower 14 are designed, cooling coils are arranged outside 29 and 31 layers, each tower plate 143 is provided with two groups of cooling coils, and each group consists of a cooling coil water feeding pipe 147 and a cooling coil water return pipe 148. A demister 141 is arranged above the uppermost tower plate 143 in the absorption tower 14, a plurality of baffle plates 145 are vertically arranged on the tower plate 143, so that the liquid flows in a double-S shape in the horizontal direction, specifically, two baffle plates 145 are arranged in parallel in the front and at the back of the middle of each tower plate 143, three baffle plates 145 are symmetrically arranged on two sides of each tower plate 143, and the baffle plates 145 on the two sides and the baffle plate 145 in the middle are arranged in an inserting manner. Two overflow pipes 142 and one manhole 146 are arranged on each layer of tower plate 143, and the positions of the overflow pipes 142 on the odd-numbered layer of tower plate and the even-numbered layer of tower plate are mirror images of each other so as to make the liquid flow in an S shape in the vertical direction. Each set of cooling coils is clamped with clamps and bolts to prevent vibration. The tower plate bracket and the tower plate are fixed by movable bolts, so that the welding deformation and stress corrosion of the tower body can be avoided, the levelness of the installed tower plate is strictly controlled, and the range of +/-2 mm is generally required. All welding parts in the tower body and the tower are made of ultra-low carbon stainless steel 304L type, and the others are 304 type. The tower skirt is made of carbon steel. The bottom of the overflow pipe 142 on the lowest tray of the absorption tower 14 is provided with a downcomer 144 to send the liquid to the bottom of the absorption tower 14, the downcomer 144 is arranged obliquely, the top of the absorption tower 14 is provided with an off-gas discharge pipeline, and the off-gas discharge pipeline is provided with a remote thermometer 49. The height of the overflow pipe 142 protruding out of the tower plates 143 is 3 cm-5 cm, and the distance between adjacent tower plates 143 is 50 cm-1 m.
The method for producing the dilute nitric acid by using the device for improving the quality of the dilute nitric acid product comprises the following steps:
(1) air uniformly enters an air filter 3 through an air silencer 1 and an air preheater 2 to be subjected to three-stage filtration, solid particles larger than 0.5 mu m in the air are filtered out, moisture in the air is removed, the filtered air is compressed through an air compressor 4 and then is divided into two paths, one path is primary air which passes through a primary air check valve 29, the other path is secondary air which passes through a secondary air check valve 39 and a secondary air flow control valve 25 and enters a secondary air cooler 16, and the volume ratio of the primary air to the secondary air is 12: 1;
(2) gas ammonia enters an ammonia-air mixer 5 through a gas ammonia flow regulating valve 21 and a gas ammonia check valve 27, primary air and the gas ammonia are uniformly mixed in the ammonia-air mixer 5, the ammonia-air ratio is controlled to be about 9.3 percent, the ammonia-air ratio is controlled to be adjusted by matching of the primary air flow regulating valve 22 and the gas ammonia through the gas ammonia flow regulating valve 21, the ammonia-air mixed gas enters an oxidation furnace 6 and reacts under the catalytic oxidation action of a platinum-rhodium catalyst 17 to generate nitric oxide, and after heat recovery is carried out on high-temperature nitric oxide in the oxidation furnace 5 through a steam superheater 18 and a waste heat boiler 19, the temperature of outlet nitric oxide is 450 ℃;
(3) the temperature of the high-temperature nitrogen oxide from the oxidation furnace 5 is reduced to 45 ℃ after heat exchange of a high-temperature gas-gas heat exchanger 7, an economizer 8 and a low-pressure reaction water cooler 9, the high-temperature nitrogen oxide enters a nitrogen oxide separator 10, a dilute acid pump 48 is connected to the bottom of the nitrogen oxide separator 10 to continuously send condensed acid to a tower plate 143 with a corresponding concentration gradient of an absorption tower 14, the nitrogen oxide gas dried and formed at the top enters a nitrogen oxide compressor 11 for pressurization, and the pressurized nitrogen oxide gas enters the lower part of a first-layer tower plate of the absorption tower 14 after being cooled by a tail gas preheater 12 and a high-pressure reaction water cooler 13;
(4) the condensed acid accumulated in the high-pressure reaction water cooler 13 is sent to the 3 rd layer tray of the absorption tower 14 from the bottom through a pipeline, and the tower gas entering the tower is contacted with the absorption water from the top of the absorption tower 14 to react on the tray to generate dilute nitric acidWhen the absorption efficiency is good, the outlet pressure of a nitrogen oxide compressor 11 is required to be controlled to be 0.9MPa, the gas temperature at the inlet of an absorption tower 14 (namely the temperature of a remote thermometer 53) is 45 ℃, the temperature of tail gas at the top of the tower (namely the temperature of a remote thermometer 49) is 25 ℃, the absorption tower 14 adopts a segmented cooling structure, 1-11 layers adopt circulating cooling water with the temperature of 32 ℃ for heat exchange, 12-27 layers adopt low-temperature cooling water with the temperature of 20 ℃ for heat exchange, 28-32 layers adopt freezing water with the temperature of 12 ℃ for heat exchange, liquid flows in a double S shape in each layer of the absorption tower 14, S flows are formed between the layers (the contact area of gas phase and liquid phase is improved, the heat exchange area of gas-liquid mixture in the tower is also increased to be beneficial to the absorption of nitrogen oxide), dilute nitric acid at the bottom of the absorption tower 14 is sent to the top of a bleaching tower 15 through a, the nitric acid product and the nitric acid product are in countercurrent contact with each other to strip out nitrogen oxide gas dissolved in the nitric acid product, and the bleaching gas is discharged from the top of a bleaching tower 15 and NO at the inlet of a nitrogen oxide separator 102The gas is mixed and finally enters a nitrogen oxide compressor 11 to be pressurized, qualified dilute nitric acid products come out from the bottom of a bleaching tower 15 and are cooled to 50 ℃ by a finished product acid cooler 20, and the dilute nitric acid products are delivered outside under the control of a finished product acid liquid level regulating valve 24.
Analysis of concrete implementation
TABLE 1 summary of the major parameters before and after improvement
TABLE 2 summary of the main parameters of the before and after improvement
Table 1 shows that the capacity increases after technical modification, which indicates that the measure of modifying the nitrogen oxide separator is used to improve the mechanical performance of the nitrogen oxide compressor, and the solution for increasing the concentration of the nitric acid product is feasible.
It can be seen from table 2 that under the condition that the furnace temperature is unchanged in the same period every year, the ammonia-to-air ratio is reduced, the liquid ammonia consumption is reduced, the product concentration is improved, and it is shown that the high-precision filter cloth keeps the catalyst bed layer clean and pollution-free, the novel multifunctional net increases the active area of the catalyst, improves the conversion rate of ammonia, and reduces the unit consumption of the product.
While the present invention has been described with reference to preferred embodiments, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.
Claims (10)
1. A device for improving the quality of dilute nitric acid products is characterized by comprising an air compression system, an oxidation system, a cooling system and an absorption system, wherein the air compression system comprises an air inlet silencer, an air preheater, an air filter and an air compressor, the oxidation system comprises an ammonia-air mixer and an oxidation furnace, the cooling system comprises a high-temperature gas-gas heat exchanger, an economizer, a low-pressure reaction water cooler, a nitrogen oxide separator, a nitrogen oxide compressor, a tail gas preheater and a high-pressure reaction water cooler which are sequentially connected through pipelines, the absorption system comprises an absorption tower, a bleaching tower, a finished product acid cooler and a secondary air cooler which are sequentially connected through pipelines, the air inlet silencer, the air preheater and the air filter are sequentially connected, the air filter is connected with the air compressor through pipelines, and a primary air pipeline and a secondary air pipeline are arranged at the tail end branch of a main pipeline at the outlet of the air compressor, the primary air pipeline is connected with the ammonia-air mixer, the secondary air pipeline is connected with the secondary air cooler, the upper part of the oxidation furnace is provided with a catalyst basket, the lower part of the oxidation furnace is sequentially provided with a steam superheater and a waste heat boiler, a plurality of catalyst layers and a plurality of supporting nets are arranged in the oxidation furnace, cooling coils are arranged on tower plates of the absorption tower, a plurality of baffle plates are further arranged on tower plates of the absorption tower, so that liquid flows in a double S shape in the horizontal direction, a plurality of overflow pipes are arranged on each tower plate, and the positions of the overflow pipes on the tower plates of the odd number layers and the tower plates of the even number layers are in mirror symmetry with each other.
2. The apparatus according to claim 1, wherein the ammonia-air mixer has two inlets, one inlet is connected to the outlet of the air compressor via a pipeline, the other inlet is a gas ammonia inlet pipeline, the pipeline is provided with a gas ammonia flow regulating valve, a pressure gauge, a remote thermometer, a flow meter and a gas ammonia check valve, the main pipeline of the outlet of the air compressor is provided with a pressure gauge and a remote thermometer, the primary air pipeline is provided with a primary air check valve, a primary air flow regulating valve, a pressure gauge, a remote thermometer and a flow meter, the secondary air pipeline is provided with a secondary air check valve, a flow meter and a secondary air flow regulating valve, the outlet of the ammonia-air mixer is connected to the top of the oxidation furnace via a pipeline, the pipeline is provided with a remote thermometer and an expansion joint, the oxidation furnace is provided with 11 catalyst layers and 6 support nets, and are distributed as follows: the uppermost layer of the support net supports 6 catalyst layers, the rest support nets support one catalyst layer each layer, and the lowermost layer of the support net is fixed in the catalyst frame through Raschig rings.
3. The apparatus for improving the quality of the dilute nitric acid product according to claim 1, wherein the nitrogen oxide separator is provided with a gas phase outlet and a liquid phase outlet, the gas phase outlet is connected with the nitrogen oxide compressor through a pipeline, the liquid phase outlet is connected with the dilute acid pump through a pipeline, the tail end of an outlet pipeline of the dilute acid pump is divided into five paths which are respectively connected with the tower plates from the 7 th layer to the 11 th layer of the absorption tower, the high-pressure reaction water cooler is provided with a gas outlet and a liquid outlet, the gas outlet is connected with the lower part of the first layer of the tower plate of the absorption tower through a pipeline, and the liquid outlet is connected with the 3 rd layer of the.
4. The apparatus of claim 1, wherein the bleaching tower is provided with a secondary air inlet, a gas outlet, a dilute nitric acid inlet and a dilute nitric acid outlet, the secondary air inlet is connected with the outlet of the secondary air cooler through a pipeline, the gas outlet is provided with an output pipeline, the output pipeline is communicated with a pipeline between the low-pressure reaction water cooler and the nitrogen oxide separator, the dilute nitric acid inlet is connected with the bottom outlet of the absorption tower through a pipeline, and the dilute nitric acid outlet is connected with the finished product acid cooler through a pipeline.
5. The apparatus for improving the quality of the dilute nitric acid product according to claim 1, wherein a wire mesh demister is arranged at the upper part in the nitrogen oxide separator, a blade separator is arranged below the wire mesh demister, the wire mesh demister is a cylinder consisting of a side wall and a top wall arranged at the top end of the side wall, and spraying mechanisms are arranged at the upper part of the wire mesh demister, above and below the blade separator and connected with a spraying pipeline.
6. The apparatus as claimed in claim 1, wherein the top of the absorption tower is provided with a tail gas discharge pipe, the upper part of the uppermost tower plate in the absorption tower is provided with a demister, the bottom of the overflow pipe on the lowermost tower plate in the absorption tower is provided with a downcomer for feeding liquid into the bottom of the absorption tower, and the bottom of the finished acid cooler is provided with a finished acid delivery pipe.
7. The device for improving the quality of the dilute nitric acid product according to claim 6, wherein the tower plates of the absorption tower are 32 layers, two groups of cooling coils are arranged on the rest layers except 29 and 31 layers, the downcomer is arranged in an inclined mode, the height of the overflow pipe protruding out of the tower plates is 3-5 cm, and the distance between every two adjacent tower plates is 50-1 m.
8. The apparatus for improving the quality of the dilute nitric acid product according to any one of claims 1 to 7, wherein the air filter is a three-stage filter, the primary filtration precision is 5 μm, the secondary filtration precision is 3 μm, and the tertiary filtration precision is 0.5 μm, a pressure gauge is arranged between each stage of the air filter, a telemetering thermometer is arranged on a pipeline between the oxidation furnace and the high-temperature gas-gas heat exchanger, a telemetering thermometer is arranged on an inlet pipeline of the nitrogen oxide separator, a telemetering thermometer and a liquid level meter are arranged on the main body of the nitrogen oxide separator, and a condensed acid regulating valve is arranged on an outlet pipeline of the dilute acid pump so as to realize automatic regulation according to a liquid level control index of the nitrogen; be equipped with compressed nitrogen oxide check valve and pressure gauge on the pipeline between nitrogen oxide compressor and the tail gas preheater, the pipeline is equipped with the teletransmission thermometer between high-pressure reaction water cooler gas outlet and the absorption tower, set up the teletransmission thermometer on the pipeline between secondary air cooler to the bleaching tower, be equipped with the teletransmission thermometer on the tail gas discharge pipeline at absorption tower top, be equipped with the liquid level control valve on the pipeline between absorption tower and the bleaching tower, be equipped with teletransmission thermometer and finished product acidizing fluid level regulating valve on the finished product acid outward transport pipeline, the teletransmission thermometer, the teletransmission pressure gauge, the teletransmission flowmeter, the DCS system is all even gone into to the governing valve.
9. A method for producing dilute nitric acid by using the apparatus for improving the quality of dilute nitric acid product according to any of claims 1 to 8, characterized in that the process is as follows:
(1) air uniformly enters an air filter through an air silencer and an air preheater to be subjected to three-stage filtration, solid particles larger than 0.5 mu m in the air are filtered out, moisture in the air is removed, the filtered air is compressed by an air compressor and then is divided into two paths, one path of the filtered air is primary air which passes through a primary air check valve, a primary air flow regulating valve enters an ammonia-air mixer, and the other path of the filtered air is secondary air which passes through a secondary air check valve, and a secondary air flow regulating valve enters a secondary air cooler;
(2) uniformly mixing primary air and gas ammonia in an ammonia-air mixer, enabling the gas ammonia to enter the ammonia-air mixer through a gas ammonia flow regulating valve and a gas ammonia check valve, controlling the ammonia-air ratio to be 9-9.5%, enabling the ammonia-air mixed gas to enter an oxidation furnace, reacting to generate nitric oxide under the catalytic oxidation action of a platinum-rhodium catalyst, and recovering heat of high-temperature nitric oxide in the oxidation furnace through a steam superheater and a waste heat boiler;
(3) the high-temperature nitrogen oxide from the oxidation furnace is subjected to heat exchange through a high-temperature gas-gas heat exchanger, an economizer and a low-pressure reaction water cooler, the temperature is reduced to 45 ℃ and then enters a nitrogen oxide separator, a dilute acid pump is connected to the bottom of the nitrogen oxide separator to continuously send condensed acid to tower plates with corresponding concentration gradients of the absorption tower, the nitrogen oxide gas dried at the top enters a nitrogen oxide compressor for pressurization, and the pressurized nitrogen oxide gas passes through a tail gas preheater and is cooled by a high-pressure reaction water cooler and then enters the lower part of a first-layer tower plate of the absorption tower;
(4) condensed acid accumulated in a high-pressure reaction water cooler is discharged from the bottom and is conveyed to a 3 rd layer of tower plate of an absorption tower through a pipeline, tower gas entering the tower and absorption water from the top of the absorption tower are in contact reaction on the tower plate to generate dilute nitric acid, the absorption tower adopts a sectional cooling structure, 1-11 layers adopt circulating cooling water for heat exchange, 12-27 layers adopt low-temperature cooling water for heat exchange, 28-32 layers adopt chilled water for heat exchange, liquid flows in a double-S shape on each layer of the absorption tower and flows in an S shape between the layers, the dilute nitric acid at the bottom of the absorption tower is conveyed to the top of a bleaching tower through a liquid level regulating valve, secondary air enters from the lower part of a first layer of pedal of the bleaching tower, the secondary air and the chilled water contact with each other in a countercurrent mode to discharge nitric oxide gas dissolved in a nitric acid product2Mixing the gas, finally entering a nitrogen oxide compressor to be pressurized, discharging qualified dilute nitric acid products from the bottom of the bleaching tower, cooling the dilute nitric acid products to 50 ℃ through a finished product acid cooler, and delivering the dilute nitric acid products outside through a finished product acid liquid level regulating valve.
10. The method for producing the dilute nitric acid by using the device for improving the quality of the dilute nitric acid product, according to claim 9, is characterized in that the volume ratio of primary air to secondary air is 12:1, the temperature of ammonia-air mixed gas at the inlet of the oxidation furnace is 180 ℃, the reaction temperature of the oxidation furnace is 830 ℃, and the temperature of nitrogen oxides at the outlet is 450 ℃; the outlet pressure of the nitrogen oxide compressor is 0.9MPa, the temperature of the nitrogen oxide at the inlet of the absorption tower is 45 ℃, the temperature of the absorption water is 18 ℃, and the outlet temperature of the tail gas at the top of the absorption tower is 25 ℃.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202011404815.8A CN112279226A (en) | 2020-12-04 | 2020-12-04 | Device and method for improving quality of dilute nitric acid product |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202011404815.8A CN112279226A (en) | 2020-12-04 | 2020-12-04 | Device and method for improving quality of dilute nitric acid product |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN112279226A true CN112279226A (en) | 2021-01-29 |
Family
ID=74426099
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202011404815.8A Pending CN112279226A (en) | 2020-12-04 | 2020-12-04 | Device and method for improving quality of dilute nitric acid product |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN112279226A (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113683066A (en) * | 2021-09-13 | 2021-11-23 | 太原柏悟化工科技有限公司 | Process for producing dilute nitric acid by medium-pressure method |
| CN114288835A (en) * | 2021-12-02 | 2022-04-08 | 赛鼎工程有限公司 | Structure and method for improving oxidation degree and efficiency in 65% -68% high-concentration dilute acid preparation process |
| CN114307595A (en) * | 2021-12-02 | 2022-04-12 | 赛鼎工程有限公司 | Efficient absorption tower for producing composite nitric acid and method for preparing acid |
| CN116518405A (en) * | 2023-07-03 | 2023-08-01 | 山西潞安环保能源开发股份有限公司 | Pulverized coal injection combustion device and method capable of automatically adding and mixing additives |
Citations (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1170976A (en) * | 1966-05-03 | 1969-11-19 | Chemie Linz Ag | Recovery of platinum metals from a gas steam |
| RU2024294C1 (en) * | 1990-02-22 | 1994-12-15 | Барелко Виктор Владимирович | Catalytic member of ammonium conversion |
| CN101554585A (en) * | 2009-05-08 | 2009-10-14 | 中国化工供销太原贵金属有限公司 | Dual-function knitted catalytic gauze used for nitric acid manufacture |
| CN202506160U (en) * | 2012-02-29 | 2012-10-31 | 甘肃蓝科石化高新装备股份有限公司 | Slurry stripping tower with overflow weirs |
| CN203183847U (en) * | 2013-04-17 | 2013-09-11 | 西安同大实业有限公司 | High-efficiency nitric oxide separator for nitric acid device |
| CN104495768A (en) * | 2015-01-13 | 2015-04-08 | 四川美丰化工股份有限公司 | Method and device for improving ammoxidation rate of nitric acid manufacture |
| CN206793088U (en) * | 2017-06-02 | 2017-12-26 | 宁波中科远东催化工程技术有限公司 | A kind of sulfuric acid vapor condenser of wet method Sulphuric acid |
| CN110550614A (en) * | 2019-03-25 | 2019-12-10 | 四川金象赛瑞化工股份有限公司 | Process for producing dilute nitric acid |
| CN213679839U (en) * | 2020-12-04 | 2021-07-13 | 河南神马尼龙化工有限责任公司 | Device for improving quality of dilute nitric acid product |
-
2020
- 2020-12-04 CN CN202011404815.8A patent/CN112279226A/en active Pending
Patent Citations (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1170976A (en) * | 1966-05-03 | 1969-11-19 | Chemie Linz Ag | Recovery of platinum metals from a gas steam |
| RU2024294C1 (en) * | 1990-02-22 | 1994-12-15 | Барелко Виктор Владимирович | Catalytic member of ammonium conversion |
| CN101554585A (en) * | 2009-05-08 | 2009-10-14 | 中国化工供销太原贵金属有限公司 | Dual-function knitted catalytic gauze used for nitric acid manufacture |
| CN202506160U (en) * | 2012-02-29 | 2012-10-31 | 甘肃蓝科石化高新装备股份有限公司 | Slurry stripping tower with overflow weirs |
| CN203183847U (en) * | 2013-04-17 | 2013-09-11 | 西安同大实业有限公司 | High-efficiency nitric oxide separator for nitric acid device |
| CN104495768A (en) * | 2015-01-13 | 2015-04-08 | 四川美丰化工股份有限公司 | Method and device for improving ammoxidation rate of nitric acid manufacture |
| CN206793088U (en) * | 2017-06-02 | 2017-12-26 | 宁波中科远东催化工程技术有限公司 | A kind of sulfuric acid vapor condenser of wet method Sulphuric acid |
| CN110550614A (en) * | 2019-03-25 | 2019-12-10 | 四川金象赛瑞化工股份有限公司 | Process for producing dilute nitric acid |
| CN213679839U (en) * | 2020-12-04 | 2021-07-13 | 河南神马尼龙化工有限责任公司 | Device for improving quality of dilute nitric acid product |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113683066A (en) * | 2021-09-13 | 2021-11-23 | 太原柏悟化工科技有限公司 | Process for producing dilute nitric acid by medium-pressure method |
| CN114288835A (en) * | 2021-12-02 | 2022-04-08 | 赛鼎工程有限公司 | Structure and method for improving oxidation degree and efficiency in 65% -68% high-concentration dilute acid preparation process |
| CN114307595A (en) * | 2021-12-02 | 2022-04-12 | 赛鼎工程有限公司 | Efficient absorption tower for producing composite nitric acid and method for preparing acid |
| CN116518405A (en) * | 2023-07-03 | 2023-08-01 | 山西潞安环保能源开发股份有限公司 | Pulverized coal injection combustion device and method capable of automatically adding and mixing additives |
| CN116518405B (en) * | 2023-07-03 | 2023-11-07 | 山西潞安环保能源开发股份有限公司 | Pulverized coal injection combustion device and method capable of automatically adding and mixing additives |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN112279226A (en) | Device and method for improving quality of dilute nitric acid product | |
| US3780499A (en) | System for the liquid-phase removal of a component from the gas stream especially the absorption of sulfur trioxide in sulfuric acid | |
| AU2017326895B2 (en) | Plant and process for producing nitric acid | |
| CN213679839U (en) | Device for improving quality of dilute nitric acid product | |
| CN204307461U (en) | Steam generator system high temperature fume dust removal device | |
| CN102320579A (en) | Technical method for preparing sulfuric acid from hydrogen sulfide | |
| CN111470941A (en) | High-quality cyclohexanol production device and process | |
| CN211514013U (en) | Continuous absorption device for byproduct hydrogen chloride gas in chlorination reaction | |
| CN215463249U (en) | Partitioned multistage circulating CO2Trapping concentration system | |
| CN212581530U (en) | Silicon tetrachloride cold hydrogenation system | |
| CN208413844U (en) | The purifying plant of high yield super clean, high purified hydrofluoric acid | |
| CN102107119A (en) | Multiple-effect membrane distillation device and method | |
| CN208244357U (en) | A kind of flue gas cleaning system | |
| CN113998677B (en) | CO recovery from chemical process 2 System and method for preparing nitrogen from waste gas of (a) a reactor | |
| CN116496225A (en) | Melamine production method and equipment | |
| CN201325876Y (en) | High-purity energy-saving type purifying device | |
| US4552744A (en) | Process for the production of sulfuric acid using coated catalysts | |
| CN212450644U (en) | Two-stage dihydrate wet-process phosphoric acid production device | |
| CN113230831A (en) | System and method for washing, arsenic removal and purification of nonferrous smelting flue gas through adiabatic evaporation and cooling | |
| CN2769807Y (en) | Orifice corrugated pipe heat exchanger | |
| CN110295072B (en) | Small skid-mounted natural gas purification device and purification method | |
| CN106823724A (en) | A kind of flue gas integrated purification system for realizing wastewater zero discharge | |
| CN211025457U (en) | Process gas separator for nitric acid device adopting double-pressurization method | |
| CN112158848A (en) | Silicon tetrachloride cold hydrogenation system | |
| CN101624343A (en) | Hydrogen recycling method and device of refining unit of pure terephthalic acid device |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination |