CN114405450A - Filling type urea catalytic hydrolysis device - Google Patents
Filling type urea catalytic hydrolysis device Download PDFInfo
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- CN114405450A CN114405450A CN202210170920.2A CN202210170920A CN114405450A CN 114405450 A CN114405450 A CN 114405450A CN 202210170920 A CN202210170920 A CN 202210170920A CN 114405450 A CN114405450 A CN 114405450A
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- hydrolysis
- urea
- filler
- reaction kettle
- hydrolysis reaction
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- 238000006460 hydrolysis reaction Methods 0.000 title claims abstract description 114
- XSQUKJJJFZCRTK-UHFFFAOYSA-N Urea Chemical compound NC(N)=O XSQUKJJJFZCRTK-UHFFFAOYSA-N 0.000 title claims abstract description 88
- 239000004202 carbamide Substances 0.000 title claims abstract description 88
- 230000007062 hydrolysis Effects 0.000 title claims abstract description 51
- 230000003197 catalytic effect Effects 0.000 title claims abstract description 34
- 238000011049 filling Methods 0.000 title claims description 11
- 239000000945 filler Substances 0.000 claims abstract description 75
- 239000007788 liquid Substances 0.000 claims abstract description 52
- 238000012856 packing Methods 0.000 claims abstract description 34
- 238000005192 partition Methods 0.000 claims abstract description 19
- 239000000463 material Substances 0.000 claims description 6
- 230000003301 hydrolyzing effect Effects 0.000 claims 1
- 238000000034 method Methods 0.000 abstract description 12
- 230000008569 process Effects 0.000 abstract description 6
- 230000008021 deposition Effects 0.000 abstract description 4
- 239000007787 solid Substances 0.000 abstract description 4
- 239000007789 gas Substances 0.000 description 44
- 239000000243 solution Substances 0.000 description 30
- 239000003054 catalyst Substances 0.000 description 23
- 239000012071 phase Substances 0.000 description 14
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 description 11
- 239000010865 sewage Substances 0.000 description 9
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 9
- 238000006243 chemical reaction Methods 0.000 description 7
- 239000011248 coating agent Substances 0.000 description 7
- 238000000576 coating method Methods 0.000 description 7
- 238000012546 transfer Methods 0.000 description 7
- 238000005516 engineering process Methods 0.000 description 6
- 238000011068 loading method Methods 0.000 description 6
- 238000004140 cleaning Methods 0.000 description 5
- 230000001965 increasing effect Effects 0.000 description 5
- 239000007791 liquid phase Substances 0.000 description 5
- 239000000203 mixture Substances 0.000 description 5
- 239000003513 alkali Substances 0.000 description 4
- 229910021529 ammonia Inorganic materials 0.000 description 4
- 239000012530 fluid Substances 0.000 description 4
- 239000000047 product Substances 0.000 description 4
- 238000000926 separation method Methods 0.000 description 4
- 239000000126 substance Substances 0.000 description 4
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 description 3
- 238000010586 diagram Methods 0.000 description 3
- 239000003546 flue gas Substances 0.000 description 3
- 238000010438 heat treatment Methods 0.000 description 3
- 239000000413 hydrolysate Substances 0.000 description 3
- 238000004064 recycling Methods 0.000 description 3
- 230000008929 regeneration Effects 0.000 description 3
- 238000011069 regeneration method Methods 0.000 description 3
- 229920006395 saturated elastomer Polymers 0.000 description 3
- 230000009471 action Effects 0.000 description 2
- 238000007664 blowing Methods 0.000 description 2
- 239000006227 byproduct Substances 0.000 description 2
- 239000002131 composite material Substances 0.000 description 2
- 238000005265 energy consumption Methods 0.000 description 2
- 230000002209 hydrophobic effect Effects 0.000 description 2
- 238000007654 immersion Methods 0.000 description 2
- 238000005470 impregnation Methods 0.000 description 2
- 239000012535 impurity Substances 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 229910044991 metal oxide Inorganic materials 0.000 description 2
- 150000004706 metal oxides Chemical class 0.000 description 2
- 239000000843 powder Substances 0.000 description 2
- 238000002360 preparation method Methods 0.000 description 2
- 230000001737 promoting effect Effects 0.000 description 2
- 239000002994 raw material Substances 0.000 description 2
- 238000005507 spraying Methods 0.000 description 2
- VHUUQVKOLVNVRT-UHFFFAOYSA-N Ammonium hydroxide Chemical compound [NH4+].[OH-] VHUUQVKOLVNVRT-UHFFFAOYSA-N 0.000 description 1
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 1
- 230000004913 activation Effects 0.000 description 1
- 230000004075 alteration Effects 0.000 description 1
- 235000011114 ammonium hydroxide Nutrition 0.000 description 1
- 238000013459 approach Methods 0.000 description 1
- 239000007864 aqueous solution Substances 0.000 description 1
- 230000001174 ascending effect Effects 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- OHJMTUPIZMNBFR-UHFFFAOYSA-N biuret Chemical compound NC(=O)NC(N)=O OHJMTUPIZMNBFR-UHFFFAOYSA-N 0.000 description 1
- 238000010531 catalytic reduction reaction Methods 0.000 description 1
- 229910010293 ceramic material Inorganic materials 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 239000003638 chemical reducing agent Substances 0.000 description 1
- 238000000354 decomposition reaction Methods 0.000 description 1
- 238000009792 diffusion process Methods 0.000 description 1
- 239000012153 distilled water Substances 0.000 description 1
- 230000002708 enhancing effect Effects 0.000 description 1
- 230000005484 gravity Effects 0.000 description 1
- 230000002401 inhibitory effect Effects 0.000 description 1
- 238000012423 maintenance Methods 0.000 description 1
- 239000011259 mixed solution Substances 0.000 description 1
- 238000002156 mixing Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 230000035484 reaction time Effects 0.000 description 1
- 238000011084 recovery Methods 0.000 description 1
- 230000004044 response Effects 0.000 description 1
- 231100000817 safety factor Toxicity 0.000 description 1
- 239000011949 solid catalyst Substances 0.000 description 1
- 239000007921 spray Substances 0.000 description 1
- 238000003756 stirring Methods 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
- 238000003786 synthesis reaction Methods 0.000 description 1
- 238000005406 washing Methods 0.000 description 1
- 239000002699 waste material Substances 0.000 description 1
Images
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J19/00—Chemical, physical or physico-chemical processes in general; Their relevant apparatus
- B01J19/24—Stationary reactors without moving elements inside
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D29/00—Filters with filtering elements stationary during filtration, e.g. pressure or suction filters, not covered by groups B01D24/00 - B01D27/00; Filtering elements therefor
- B01D29/01—Filters with filtering elements stationary during filtration, e.g. pressure or suction filters, not covered by groups B01D24/00 - B01D27/00; Filtering elements therefor with flat filtering elements
- B01D29/03—Filters with filtering elements stationary during filtration, e.g. pressure or suction filters, not covered by groups B01D24/00 - B01D27/00; Filtering elements therefor with flat filtering elements self-supporting
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J19/00—Chemical, physical or physico-chemical processes in general; Their relevant apparatus
- B01J19/0006—Controlling or regulating processes
- B01J19/0013—Controlling the temperature of the process
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J19/00—Chemical, physical or physico-chemical processes in general; Their relevant apparatus
- B01J19/0053—Details of the reactor
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J4/00—Feed or outlet devices; Feed or outlet control devices
- B01J4/001—Feed or outlet devices as such, e.g. feeding tubes
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01C—AMMONIA; CYANOGEN; COMPOUNDS THEREOF
- C01C1/00—Ammonia; Compounds thereof
- C01C1/02—Preparation, purification or separation of ammonia
- C01C1/08—Preparation of ammonia from nitrogenous organic substances
- C01C1/086—Preparation of ammonia from nitrogenous organic substances from urea
-
- 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
Abstract
The invention provides a filler type urea catalytic hydrolysis device which is simple in structure, effectively improves the catalytic effect of urea hydrolysis, improves the hydrolysis reaction rate, solves the problem of deposition and blockage of insoluble solid matters in the high-pressure hydrolysis process of a high-concentration urea kettle body, and improves the heat exchange efficiency. A filler type urea catalytic hydrolysis device comprises a hydrolysis reaction kettle, wherein a gas outlet is formed in the top of the hydrolysis reaction kettle, the hydrolysis reaction kettle divides the interior of the hydrolysis reaction kettle into a heat exchange area and a filler area through a partition plate arranged at the bottom of the hydrolysis reaction kettle, and an overflow weir notch is formed in the top end of the partition plate; a heat exchanger is arranged in the heat exchange area, and a urea solution inlet is formed in the bottom of the heat exchange area; the gas distributor, the supporting grid and the liquid distributor are sequentially arranged from the bottom to the top end of the partition plate in the packing area, the side walls of the supporting grid, the liquid distributor, the partition plate and the hydrolysis reaction kettle jointly surround to form a packing layer for placing packing, and a gas inlet and a circulating liquid outlet are formed in the bottom of the packing area.
Description
Technical Field
The invention relates to the technical field of flue gas denitration of thermal power plants, in particular to a filler type urea catalytic hydrolysis device.
Background
In the selective catalytic reduction technology in the flue gas denitration technology of the thermal power plant, the preparation of the reducing agent ammonia usually adopts three sources of liquid ammonia, ammonia water and urea. In recent years, due to the importance of safety factors and potential risks, the market demand of the urea hydrolysis ammonia production technology is increased. The urea hydrolysis technology is mature and applied to a waste liquid recovery process for urea synthesis in the chemical industry, and the main principle is that urea aqueous solution with certain concentration is utilized to perform hydrolysis reaction under certain pressure and temperature, and finally ammonia gas is generated. The urea hydrolysis technology is applied to the field of ammonia preparation by flue gas denitration, and has the advantages of high urea conversion rate, simple process, low energy consumption and the like. However, the urea hydrolysis reaction rate is slow, so that the requirement of variable load working conditions on response time cannot be well met, and the urea catalytic hydrolysis technology is an approach for effectively promoting the urea decomposition rate except for timely adjustment of process parameters.
The traditional urea catalytic hydrolysis device is usually carried out in an inner-outer double-layer reaction kettle with stirring, mass transfer diffusion is generated through the liquid level of urea solution under the action of added catalyst, and gas-phase products are sent out from an outlet at the top of the kettle under certain pressure and temperature. And the composite catalyst is also adopted and is sent into the urea solution in an on-line supply mode, and the urea catalytic hydrolysis reaction is carried out in a catalyst coating mode. The urea catalytic hydrolysis for preparing ammonia can effectively reduce the steam consumption, reduce the operation temperature and pressure, and simultaneously reduce the activation energy required by urea hydrolysis, thereby reducing the operation cost of the system.
The existing urea catalytic hydrolysis device has the problems that the traditional urea hydrolysis reaction is carried out at a higher reaction temperature, particularly, urea solution with higher concentration is usually adopted for urea hydrolysis for denitration of a coal-fired power plant, enough reaction time cannot be ensured in a reactor with a fixed volume, and NH generated by hydrolysis cannot be taken away in time3And CO2Free NH present in the urea solution3Free NH with hydrolysis inhibiting effect3The urea hydrolysis rate is reduced, which results in that the urea solution in the reactor with a high concentration cannot be completely hydrolyzed in time. In addition, the heat required by the low-temperature urea solution and the high-temperature materials in the system do not exchange heat efficiently, so that the energy consumption is increased, and the operation cost is increased.
Disclosure of Invention
In order to solve the problems in the prior art, the invention provides a filler type urea catalytic hydrolysis device which is simple in structure, effectively improves the catalytic effect of urea hydrolysis, improves the hydrolysis reaction rate, solves the problem of deposition and blockage of insoluble solid substances in the high-pressure hydrolysis process of a high-concentration urea kettle body, and improves the heat exchange efficiency.
In order to achieve the purpose, the invention provides the following technical scheme:
a filler type urea catalytic hydrolysis device comprises a hydrolysis reaction kettle, wherein a gas outlet is formed in the top of the hydrolysis reaction kettle, the hydrolysis reaction kettle divides the interior of the hydrolysis reaction kettle into a heat exchange area and a filler area through a partition plate arranged at the bottom of the hydrolysis reaction kettle, and an overflow weir notch is formed in the top end of the partition plate;
a heat exchanger is arranged in the heat exchange area, and a urea solution inlet is formed in the bottom of the heat exchange area;
the gas distributor, the supporting grid and the liquid distributor are sequentially arranged from the bottom to the top end of the partition plate in the packing area, the side walls of the supporting grid, the liquid distributor, the partition plate and the hydrolysis reaction kettle jointly surround to form a packing layer for placing packing, and a gas inlet and a circulating liquid outlet are formed in the bottom of the packing area.
Preferably, the bottom of the filling area is also provided with a drain outlet, and a filter screen is arranged at the outlet of the drain outlet.
Preferably, the packing of the packing layer adopts one of corrugated plates, Raschig rings or pall rings.
Preferably, the length of the liquid distributor is greater than the length of the gas distributor.
Preferably, one side of the hydrolysis reaction kettle heat exchange area is provided with a protruding section with an inclined angle.
Preferably, the hydrolysis reaction kettle is a horizontal reaction kettle.
Preferably, the heat exchanger is a shell and tube heat exchanger.
Preferably, the support grid is arranged at an oblique angle.
Preferably, the circulating liquid outlet is connected with the urea solution inlet through a pipeline, and the gas outlet at the top of the hydrolysis reaction kettle is connected with the gas inlet at the bottom through a pipeline.
Preferably, a demister is further arranged at a gas outlet at the top of the hydrolysis reaction kettle.
Compared with the prior art, the invention has the following beneficial effects:
the invention provides a filler type urea catalytic hydrolysis device, which adopts a filler mode, wherein a filler area is arranged in a hydrolysis reaction kettle, gas is introduced through a gas inlet arranged at the bottom of the filler area, urea solution flows in from a urea solution inlet, and flows into the filler area provided with the filler along an overflow weir crest at the top end of a partition plate after being provided with certain heat through a heat exchanger, the urea solution flows from top to bottom along a filler surface structure to form a liquid film which is dispersed in introduced continuously flowing gas, the urea solution and hydrolysate gas are converged in the filler layer, the gas-liquid two-phase contact surface is arranged on the liquid film surface of the filler, the high-specific-surface-area filler structure enables the gas-liquid two phases to be fully contacted, the area between two-phase fluids is increased, the heat transfer quality between the urea hydrolysis gas-liquid two phases is enhanced, and the separation of gas phase and the hydrolysis rate of liquid phase are promoted, effectively improves the catalytic effect of urea hydrolysis and achieves the aim of improving the hydrolysis reaction rate.
Furthermore, the bottom of the filler area is also provided with a drain outlet, a filter screen is arranged at the outlet of the drain outlet, the support grid is arranged in an inclined angle to form a slope, the filler to be treated is intercepted by the filter screen and then drained, when the catalyst needs to be cleaned or regenerated, the filter screen is taken out, the filler is drained from the drain outlet along the slope formed by the support grid, and the filler is sent to the links of filler cleaning, catalyst regeneration and catalyst coating, the filler is cleaned irregularly to bring out byproducts in high-temperature high-concentration urea hydrolysis, such as biuret for cleaning and removing, and the problems of deposition and blockage of insoluble solid substances in the high-pressure hydrolysis process of high-concentration urea are solved to a certain extent.
Drawings
FIG. 1 is a schematic diagram of a packed urea catalytic hydrolysis unit according to the present invention;
FIG. 2 is a schematic structural diagram of a Raschig ring packing in an embodiment of the invention;
FIG. 3 is a schematic structural diagram of a pall ring packing according to an embodiment of the present invention;
FIG. 4 is a top view of the structure of the pall ring packing in the embodiment of the present invention.
In the figure, a heat exchanger inlet 1, a heat exchanger outlet 2, a heating tube bundle 3, a urea solution inlet 4, a hydrolysis reaction kettle 5, a partition plate 6, an overflow weir port 7, a liquid distributor 8, a packing layer 9, a gas distributor 10, a gas inlet 11, a circulating liquid outlet 12, a filter screen 13, a reaction kettle liquid level meter 14, a safety valve 15, a demister 16, a drain outlet 17, a support grid 18 and a gas outlet 19.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
The invention relates to a filler type urea catalytic hydrolysis device, which comprises a hydrolysis reaction kettle 5, wherein the top of the hydrolysis reaction kettle 5 is provided with a gas outlet 19, the hydrolysis reaction kettle 5 divides the interior of the hydrolysis reaction kettle 5 into a heat exchange area and a filler area through a partition plate 6 arranged at the bottom of the hydrolysis reaction kettle 5, and the top end of the partition plate 6 is provided with an overflow weir crest 7;
a heat exchanger is arranged in the heat exchange area, and a urea solution inlet 4 is arranged at the bottom of the heat exchange area;
the gas distributor 10, the supporting grid 18 and the liquid distributor 8 are sequentially arranged from the bottom to the top end of the partition plate 6 in the packing area, the supporting grid 18, the liquid distributor 8, the partition plate 6 and the side wall of the hydrolysis reaction kettle 5 are jointly surrounded to form a packing layer 9 for placing packing with a high specific surface area structure, and the bottom of the packing area is provided with a gas inlet 11 and a circulating liquid outlet 12.
Wherein, the support grid 18 of the packing area is arranged above the gas distributor 10 and plays the role of a packing support plate, the packing is arranged above the support grid 18 in a stacking mode, and the liquid distributor 8 is longer and plays the role of a packing pressure plate to prevent the packing from entering the other side of the clapboard 6 along with the fluid.
The invention provides a filler type urea catalytic hydrolysis device, which adopts a filler mode, wherein a filler area is arranged in a hydrolysis reaction kettle 5, gas is introduced through a gas inlet 11 arranged at the bottom of the filler area, urea solution flows in from a urea solution inlet 4, after certain heat is provided by a heat exchanger, the urea solution flows into the filler area provided with the filler along an overflow weir crest 7 at the top end of a partition plate 6, the urea solution flows from top to bottom along a filler surface structure to form a liquid film, the liquid film is dispersed in the introduced continuously flowing gas, the urea solution and hydrolysate gas are converged in a filler layer 9, a gas-liquid two-phase contact surface is arranged on the surface of the liquid film of the filler, and the filler structure with high specific surface area ensures that gas and liquid phases are fully contacted, thereby not only increasing the area between two-phase fluids, but also enhancing the heat transfer quality between the gas and liquid phases of urea hydrolysis, and promoting the separation of gas phases and the hydrolysis rate of liquid phases, effectively improves the catalytic effect of urea hydrolysis and achieves the aim of improving the hydrolysis reaction rate.
Furthermore, the bottom of the filler area is also provided with a drain outlet 17, a filter screen 13 is arranged at the outlet of the drain outlet 17, the support grid 18 is arranged in an inclined angle to form a slope, the filler to be treated is intercepted by the filter screen 13 and then drained, when the catalyst needs to be cleaned or regenerated, the filter screen 13 is drawn off, the filler is drained from the drain outlet 17 along the slope formed by the support grid 18 and sent to the links of filler cleaning, catalyst regeneration and catalyst coating, the filler is cleaned irregularly to bring byproducts in the high-temperature high-concentration urea hydrolysis to be cleaned and removed, and the problems of deposition and blockage of insoluble solid substances in the high-concentration urea high-pressure hydrolysis process are solved to a certain extent.
Before loading the filler, the filler needs to be subjected to catalyst loading treatment, the composite catalyst is loaded on the surface of the filler through multiple steps, and the filler can be treated in a manner of loading a liquid catalyst through an immersion method and spraying a catalyst coating on the surface, for example, the immersion method is adopted to load an alkali liquor on the surface of the filler, and then metal oxide powder is sprayed on the surface of a dried alkali liquor catalyst, but the method is not limited to this.
When the invention is used for loading the filler, a certain volume of the filler is blown in by using an air blowing mode, or the filler is conveyed to the filler layer 9 along with the mixture of water, the mixture of the water and the filler is kept still for a period of time until the filler is settled and accumulated on the filler layer 9 after reaching the liquid level of the liquid distributor 8, a filter screen 13 device is added at the sewage discharge port 17 to discharge the input clear water, and the hydrolysis reaction kettle 5 is normally operated.
Preferably, the packing of the packing layer 9 is one of a corrugated plate, a raschig ring or a pall ring, the packing adopted by the invention is a material with a higher specific surface area, such as a corrugated plate, and the raschig ring or the modified pall ring made of a ceramic material can be used in consideration of the simplicity of disassembly and cleaning, wherein the common specification is 25-75mm in diameter and 2.5-9.5mm in wall thickness, and the size of the sewage discharge diameter at the bottom of the hydrolysis reaction kettle 5 is considered, and the packing structure with a small specification is selected as much as possible to facilitate discharge.
The Raschig ring has simple structure and low cost, the height and the diameter are almost equal, and the mode of flowing along with the fluid by the action of gravity is simple and easy to implement.
Further, the length of the liquid distributor 8 is greater than the length of the gas distributor 10.
In this embodiment, the hydrolysis reaction kettle 5 is a horizontal reaction kettle, one side of the heat exchange area of the hydrolysis reaction kettle 5 is provided with a protruding section with an inclined angle, and the inclined protruding section can increase a gas-phase product ascending path and increase the efficiency of gas-liquid separation.
In this embodiment, the heat exchanger adopts shell and tube heat exchanger, specifically comprises a set of coil pipe, and the one end of coil pipe is gone deep into hydrolysis reaction cauldron 5's the cauldron body, and the inside medium of coil pipe adopts circulating water vapour, and saturated steam gets into from heat exchanger entry 1, provides the heat for urea hydrolysis reaction, and low temperature is hydrophobic to be sent out from heat exchanger export 2, only needs to change the heat exchanger coil pipe during the maintenance, and is convenient quick, labour saving and time saving.
Further, the circulating liquid outlet 12 is connected with the urea solution inlet 4 through a pipeline, and the gas outlet 19 at the top of the hydrolysis reaction kettle 5 is connected with the gas inlet 11 at the bottom through a pipeline. In the invention, a gas-phase product after hydrolysis reaction is sent out through a gas outlet 19 at the top of the hydrolysis reaction kettle 5, and a part of the gas can be taken as circulating gas to be sent into a gas inlet 11 at the bottom of the hydrolysis reaction kettle 5 and then enters the packing layer 9 from bottom to top through a gas distributor 10 to provide gas for gas-liquid contact of the packing layer 9 for recycling, thus improving the recycling rate; the bottom of the hydrolysis reaction kettle 5 is provided with a circulating liquid outlet 12, and part of the urea solution can be used as a return material and sent to a urea raw material inlet for mixing and then recycling, so that the cost is reduced, and the economical efficiency is improved.
Specifically, as shown in fig. 1, saturated steam is introduced into a heating tube bundle 3 of a heat exchanger through an inlet 1 of a heat exchanger, so as to provide heat for a hydrolysis reaction for a urea solution in a hydrolysis reaction kettle 5, and high-temperature hydrophobic water formed by the saturated steam is sent out through an outlet 2 of the heat exchanger.
The hydrolysis reaction kettle 5 is provided with a reaction kettle liquid level meter 14 and a safety valve 15, the urea solution fed into the hydrolysis reaction kettle 5 through the urea solution inlet 4 continuously accumulates to reach a certain liquid level height after exchanging heat with a coil of the heating tube bundle 3 in the partition 6 area at the urea solution inlet 4 end, namely the heat exchange area, until the urea solution enters the partition 6 area at the sewage outlet 17 end through the overflow weir port 7, namely the filling area, firstly passes through a liquid distributor 8 arranged below the overflow weir port 7 and passes through a filling layer 9 arranged below the liquid distributor 8 from top to bottom; the gas phase product after hydrolysis reaction is sent out from the top of the hydrolysis reaction kettle 5 through a demister 16 and a gas outlet 19, and a part of the gas is taken as circulating gas to be sent into a gas inlet 11 at the bottom of the hydrolysis reaction kettle 5 and then enters a filling device from bottom to top through a gas distributor 1010.
The urea solution and the hydrolysate gas are converged in the packing layer 9, and the gas-liquid two phases are fully contacted by the packing structure with high specific surface area to carry out heat and mass transfer, so that the separation of the gas phase and the hydrolysis rate of the liquid phase are promoted; the bottom of the filling area is provided with a gas inlet 11, a circulating liquid outlet 12 and a sewage outlet 17; after the mass transfer and heat transfer of the packing layer 9, the high-temperature urea mixed solution passes through the circulating liquid outlet 12, is mixed with the fresh raw material liquid and is sent into the urea catalytic hydrolysis reaction device again to continue the next catalytic hydrolysis reaction.
And a sewage discharge outlet 17 arranged at the bottom of the hydrolysis reaction kettle 5 can discharge sewage in real time according to working conditions.
The filler to be treated is discharged from a sewage outlet 17 along a support grid 18 with a certain inclination, and when the catalyst needs to be cleaned and regenerated, the filter screen 13 and the filler are pumped out and sent to the links of filler cleaning, catalyst regeneration and catalyst coating. The catalyst loading treatment of the filler is carried out by a method of loading a liquid catalyst by an impregnation method and spraying a catalyst coating on the surface, or the impregnation method is adopted to load alkali liquor on the surface of the filler firstly and then spray metal oxide powder on the surface of a dried alkali liquor catalyst. After the filler is taken out, if the filler is blocked by certain impurities, the filler can be soaked by dilute hydrochloric acid at a certain temperature until the solution is transparent and free of impurities after being cleaned; and after washing for many times by using distilled water, repeating the steps to load the catalyst for later use.
When the filler is loaded, a certain volume of filler is blown in by using an air blowing mode, or the filler is conveyed to the filler layer 9 along with the mixture of water, the filler is settled and accumulated in the filler layer 9 after the mixture of the water and the filler reaches the liquid level of the liquid distributor 8 and stands for about 15min, and the input clean water is discharged through the filter screen 13 at the sewage discharge outlet 17, so that the urea catalytic hydrolysis reaction device is normally operated.
In the embodiment of the invention, urea solution generates urea catalytic hydrolysis reaction on the surface of the filler impregnated with the liquid catalyst and the solid catalyst coating under the conditions of the operation temperature of about 150 ℃ and the operation pressure of 0.6MPa, and generates ammonia gas mixture through gas-liquid mass transfer enhanced by the surface of the filler.
In the invention, the packing is made of a material with higher specific surface area, 1 height-diameter ratio, simple structure and lower manufacturing cost, such as a Raschig ring shown in figure 2, or an internally improved pall ring shown in figures 3 and 4, the conventional specification of the Raschig ring is 25-75mm in diameter and 2.5-9.5mm in wall thickness, and the specific size needs to consider the diameter of a sewage outlet 17 at the bottom of a hydrolysis reaction kettle 5 so as to be discharged.
Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.
Claims (10)
1. A filler type urea catalytic hydrolysis device is characterized by comprising a hydrolysis reaction kettle (5), wherein a gas outlet (19) is formed in the top of the hydrolysis reaction kettle (5), the hydrolysis reaction kettle (5) divides the interior of the hydrolysis reaction kettle (5) into a heat exchange area and a filler area through a partition plate (6) arranged at the bottom of the hydrolysis reaction kettle (5), and an overflow weir crest (7) is arranged at the top end of the partition plate (6);
a heat exchanger is arranged in the heat exchange area, and a urea solution inlet (4) is arranged at the bottom of the heat exchange area;
gas distributor (10), support grid (18) and liquid distributor (8) have set gradually from the bottom to the top of baffle (6) in the filler region, and the lateral wall that supports grid (18), liquid distributor (8), baffle (6) and hydrolysis reaction cauldron (5) surrounds jointly and forms filler layer (9) for place the filler, the bottom in filler region is equipped with gas inlet (11) and circulation liquid export (12).
2. The filling type urea catalytic hydrolysis device as claimed in claim 1, wherein a drain outlet (17) is further provided at the bottom of the filling region, and a filter screen (13) is provided at the outlet of the drain outlet (17).
3. A filled catalytic urea hydrolysis device according to claim 1, wherein the filling material of the filling material layer (9) is one of corrugated plate, raschig ring or pall ring.
4. A packed urea catalytic hydrolysis device according to claim 1, characterized in that the length of the liquid distributor (8) is greater than the length of the gas distributor (10).
5. The apparatus for catalytic hydrolysis of urea with packing according to claim 1, wherein the side of the heat exchange area of the hydrolysis reactor (5) is provided with a protruding section with an inclined angle.
6. The packed catalytic urea hydrolysis device according to claim 1, wherein the hydrolysis reactor (5) is a horizontal reactor.
7. The packed catalytic urea hydrolyzing device of claim 1, wherein the heat exchanger is a tubular heat exchanger.
8. A packed urea catalytic hydrolysis device according to claim 1, characterized in that the support grid (18) is arranged at an inclined angle.
9. The packed catalytic urea hydrolysis device according to claim 1, wherein the circulating liquid outlet (12) is connected to the urea solution inlet (4) through a pipeline, and the gas outlet (19) at the top of the hydrolysis reactor (5) is connected to the gas inlet (11) at the bottom through a pipeline.
10. The packed catalytic urea hydrolysis device according to claim 1, wherein a demister (16) is further provided at the gas outlet (19) at the top of the hydrolysis reactor (5).
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| Application Number | Priority Date | Filing Date | Title |
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| CN202210170920.2A CN114405450A (en) | 2022-02-23 | 2022-02-23 | Filling type urea catalytic hydrolysis device |
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| Application Number | Priority Date | Filing Date | Title |
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| CN202210170920.2A CN114405450A (en) | 2022-02-23 | 2022-02-23 | Filling type urea catalytic hydrolysis device |
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| CN114405450A true CN114405450A (en) | 2022-04-29 |
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| CN202210170920.2A Pending CN114405450A (en) | 2022-02-23 | 2022-02-23 | Filling type urea catalytic hydrolysis device |
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Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5240688A (en) * | 1990-08-01 | 1993-08-31 | Fuel Tech Gmbh | Process for the in-line hydrolysis of urea |
| CN202342931U (en) * | 2011-11-21 | 2012-07-25 | 南京师范大学 | Bulk packing tower section with inclined supporting plate |
| CN103011366A (en) * | 2012-12-14 | 2013-04-03 | 太原理工大学 | Method of carrying out catalytic hydrolysis on low-concentration urea wastewater by solid catalyst |
| CN103482649A (en) * | 2013-09-05 | 2014-01-01 | 西安热工研究院有限公司 | Urea solution hydrolysis reactor |
| CN113750948A (en) * | 2021-09-09 | 2021-12-07 | 西安热工研究院有限公司 | Urea catalytic hydrolysis reactor and method for flue gas denitration |
| CN216778831U (en) * | 2022-02-23 | 2022-06-21 | 西安热工研究院有限公司 | Filling type urea catalytic hydrolysis device |
-
2022
- 2022-02-23 CN CN202210170920.2A patent/CN114405450A/en active Pending
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5240688A (en) * | 1990-08-01 | 1993-08-31 | Fuel Tech Gmbh | Process for the in-line hydrolysis of urea |
| CN202342931U (en) * | 2011-11-21 | 2012-07-25 | 南京师范大学 | Bulk packing tower section with inclined supporting plate |
| CN103011366A (en) * | 2012-12-14 | 2013-04-03 | 太原理工大学 | Method of carrying out catalytic hydrolysis on low-concentration urea wastewater by solid catalyst |
| CN103482649A (en) * | 2013-09-05 | 2014-01-01 | 西安热工研究院有限公司 | Urea solution hydrolysis reactor |
| CN113750948A (en) * | 2021-09-09 | 2021-12-07 | 西安热工研究院有限公司 | Urea catalytic hydrolysis reactor and method for flue gas denitration |
| CN216778831U (en) * | 2022-02-23 | 2022-06-21 | 西安热工研究院有限公司 | Filling type urea catalytic hydrolysis device |
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