A kind of low-temperature denitration technique
Technical field
The invention belongs to gas denitrifying technology fields, more particularly to a kind of low-temperature denitration technique.
Background technique
Nitrogen oxides is collectively referred to as NOx, is one of primary pollution source of atmosphere pollution.Endanger it is maximum mainly: NO, NO2。
The main harm of NOx is as follows: (1) to the toxic effect of human body;(2) to the toxic effect of plant;(3) acid rain, acid mist can be formed;
(4) photochemical fog is formed with hydrocarbon;(5) ozone layer is destroyed.
Denitrating flue gas refers to the NOx in removing flue gas, can be divided into wet denitration and Dry denitration by Processing tecchnics.Mainly
It include: sour absorption process, Alkali absorption method, selective catalytic reduction, non-selective catalytic reduction, absorption method, gas ions activation
Method etc..Domestic and international some scientific research personnel also developed with microorganism the method for handling NOx exhaust gas.But there is industrial value,
With being most widely selective catalytic reduction (SCR).
The FCC regenerated flue gas denitration of the flue gas, oil plant of coal-burning power plant at present, which is administered, mainly uses SCR method, and mating wet
Method washing desulphurization dedusting.By taking FCC flue gas as an example, main flow is as follows: 500~600 DEG C of FCC regenerated flue gas first passes through waste heat pot
Furnace carries out recycling heat, and flue-gas temperature is reduced to 320~400 DEG C to enter SCR fixed bed reactors and carries out denitration reaction, removes cigarette
Then NOx in gas returns waste heat boiler and carries out recycling heat, flue-gas temperature is down to 150~200 DEG C, subsequently into desulfurization
SOx in flue gas is washed by dedusting washing tower with dust simultaneously using alkaline absorption solution, and flue-gas temperature is reduced to 55~60 DEG C
Discharge.Desulfurization give up absorbing liquid to be settled, be filtered, be concentrated and etc. progress solid-liquor separation, ask liquid to use after solid-liquor separation
Air aeration oxidation, COD qualified discharge, solid are filled.
Existing SCR denitration process is all made of fixed bed Benitration reactor, and catalyst uses cellular, board-like or ripple
Formula, catalyst are placed in reactor in modular form.Reducing agent NH is initially injected before reaction bed3, allow NH3With cigarette
NOx in gas is sufficiently mixed, and by denitrating catalyst bed, NOx catalysis is reduced to N2。
The prior art has the following problems:
1, due to typically containing SO in flue gas2、SO3, O2With vapor, meeting and SO when (the escaping of ammonia) when reaction zone ammonia surplus3Instead
Ammonium salt, the ammonium salt (NH of generation should be generated4HSO4), it is in a liquid state at 180~240 DEG C of temperature, there is viscosity, it is de- to be liable to stick to SCR
On the heat exchanger tube of the downstream unit economizer of nitre reactor, be bonded flue gas in dust, cause heat exchange tube layer fouling blockage with
Corrosion, influences the device cycle of operation.In order to avoid the escaping of ammonia, SCR fixed bed reactors entrance spray ammonia uniformity is generally required just
Minus deviation is less than 5%.
2, the NOx content in flue gas is related to the process conditions of master device, and variation fluctuation range is larger, and SCR fixed bed
The catalytic amount of reactor be it is fixed, once NOx concentration range exceed design value, then the NOx of purifying smoke cannot row up to standard
It puts.Therefore the operating flexibility of fixed bed is smaller.
3, during operation, the activity of catalyst is gradually reduced fixed bed reactors, when reactor outlet NOx can not be up to standard
When discharge, it is necessary to more catalyst changeout.The cycle of operation of general SCR device at least requires 3-4, otherwise will affect master device
Operating.General SCR device denitrification rate demand is at least 60~90% or more, and when more catalyst changeout, the activity of catalyst is extremely
It is few that there are also 60% or so.It can be seen that too low using utilization rate of the fixed bed SCR reactor to catalyst.
4, after general denitrating flue gas, wet scrubbing dedusting is also used, is carried out together with desulfurization, desulfurization and dedusting process produces
Raw desulfurization waste liquor will also carry out solid-liquor separation, and the numerous length of process is complicated for operation, and investment is high with operating cost.
Currently, CN102008893A describes a kind of using biography in the world still without industrialized moving bed SCR reactor
The moving-burden bed reactor of system carries out SCR reaction, needs pressure drop since flue gas passes through bed, is not suitable for exhaust gas volumn and contains greatly, in flue gas
The not high operating condition of dirt, flue gas overbottom pressure.And catalyst is moved down by gravity, when reactor is larger, is existed mobile uniform
Property problem, bed is easy blocking of building bridge, and requires the granularity of catalyst relatively high, and there are also problems for reaction uniformity.
Summary of the invention
In view of the deficiencies of the prior art, the present invention provides a kind of low-temperature denitration technique.By conventional denitration reaction in the present invention
Catalyst module in device replaces with micro-spherical catalyst, and using low-temp reaction, the ammonium salt for allowing reaction to generate is taken out of by catalyst
Reactor avoids the problem of the escaping of ammonia causes ammonium hydrogen sulfate to block bed, extends the cycle of operation of device.
Low-temperature denitration technique of the invention, including following content: low-temperature flue gas enters at the top of Benitration reactor, contains ammonia
Gaseous mixture be filled into flue gas through ammonia-spraying grid, air-flow passes through the staggered catalyst bed of multiple-layer horizontal from top to bottom,
It carries out denitration desulphurization reaction and removes NOx and SOx, the ammonium salt (NH that desulfurization generates4HSO4) be adhered on microspheroidal denitrating catalyst,
Dust in flue gas is filtered by catalyst bed simultaneously to be adhered to, and purifying smoke is discharged from reactor bottom;Wherein catalyst bed
It is made of the microspheroidal denitrating catalyst accumulated on mesh belt and conveyer belt, the traffic direction of adjacent upper layer and lower layer conveyer belt
On the contrary, upper layer microspheroidal denitrating catalyst is moved to transmission end of tape with conveyer belt, lower layer's conveyer belt is dropped down by free gravity
Traffic direction starting point, microspheroidal denitrating catalyst falls into catalyst hooper in the end of the last layer conveyer belt, through vapour
Removing ammonium salt is mentioned, is recycled;
The microspheroidal denitrating catalyst, on the basis of catalyst weight, comprising: 75% ~ 94% alumina support, 3% ~ 20%
Fe2O3With 3% ~ 20% MnO2;Catalyst is microspheroidal, 2 ~ 6mm of diameter, preferably 3 ~ 5mm, overall porosity 60% ~ 85%, Suo Youkong
In gap, the mesoporous ratio for accounting for overall porosity of 5 ~ 20nm is 15% ~ 55%, and the ratio that the macropore of 100 ~ 1000nm accounts for overall porosity is
40%~75%;Macropore is evenly distributed and three-dimensional perforation;Side pressure breaking strength is 5 ~ 20N/mm, preferably 8 ~ 18N/mm.
The BET specific surface area of microspheroidal denitrating catalyst of the invention is 120 ~ 400m20.45 ~ 1.50cm of/g, Kong Rongwei3/
g。
It can also be containing one or more of auxiliary agents such as Zr, Ce or Cu, preferably Zr, with catalysis in catalyst of the present invention
On the basis of agent total weight, auxiliary agent is calculated as 1% ~ 10% with oxide, and the sum of each component content is 100% in catalyst.
The preparation method of microspheroidal denitrating catalyst of the invention, including following content:
(1) organic compound of silicon source, polyethylene glycol and phosphinylidyne-containing amine group is dissolved in low carbon alcohol solution, be uniformly mixed obtain it is clear
Clear solution;Pyridine is added in step (1) resulting mixture, is uniformly mixed;Wherein the viscosity average molecular weigh of polyethylene glycol is
10000 ~ 3000000, preferably 100000 ~ 2000000;
(2) resulting mixture is added drop-wise in 20 ~ 50 DEG C of oil column and is shaped to microspheroidal, and aging 12 ~ 60 is small at 40 ~ 80 DEG C
When, ageing products are impregnated using low-carbon alcohols or low carbon alcohol solution, then through being separated by solid-liquid separation, solid phase is obtained through dry and roasting
Microspheroidal alumina support;
(3) with the soluble-salt oxide impregnation alumina supporter containing Mn and Fe, then drying and roasting, obtain microspheroidal denitration catalyst
Agent.
On the basis of the weight of step (1) resulting mixture, the additional amount of low carbon alcohol solution is 10% ~ 80%, and silicon source adds
Entering amount is 10% ~ 20%, and the additional amount of polyethylene glycol is 0.1% ~ 3.0%, preferably 0.2% ~ 2.0%;Wherein, in low carbon alcohol solution
Water and the mass ratio of low-carbon alcohols are 1.0 ~ 1.3;The molar ratio of the organic compound of polyethylene glycol and phosphinylidyne-containing amine group be 0.05 ~
1.0, preferably 0.1 ~ 0.8;Pyridine and Al3+Molar ratio be 3.0 ~ 9.0, preferably 3.5 ~ 7.0.
Silicon source described in step (1) is one or more of aluminum nitrate, aluminium chloride and aluminum sulfate.
Low-carbon alcohols described in step (1) and (2) are generally C5Alcohol below, preferably methanol, ethyl alcohol, normal propyl alcohol and isopropyl
One of alcohol is a variety of, preferably ethyl alcohol and/or propyl alcohol.
The organic compound of phosphinylidyne-containing amine group described in step (1) is selected as formamide, one in n,N-Dimethylformamide
Kind is a variety of.
Soaking conditions described in step (2) are as follows: 10 ~ 80 DEG C of soaking temperature, soaking time is 24 ~ 48 hours.
Drying described in step (2), be common constant pressure and dry, drying temperature be not more than 60 DEG C, preferably 20 ~ 40 DEG C,
It is dry to exist to without obvious liquid object.The roasting is to roast at 400 ~ 950 DEG C 1 ~ 24 hour, and preferably 550 ~ 850 DEG C
Roasting 5 ~ 10 hours.
The soluble-salt of step (3) described Mn is manganese nitrate, and the soluble-salt of Fe is ferric nitrate.It is helped when containing in catalyst
When agent, auxiliary agent can introduce during step (3).The soluble salt solutions of Mn and Fe described in step (3) are according to target
Catalyst composition, which calculates, to be prepared.Volume impregnation, incipient impregnation or spray impregnating mode, dip time 1- can be used
5 hours.Drying condition described in step (3): drying temperature is 100-130 DEG C, and drying time is 1-10 hours;The roasting
Condition are as follows: maturing temperature is 450-600 DEG C, and calcining time is 2-6 hours.
In catalyst preparation process of the present invention, the polyethylene glycol of special ratios and the organic compound of phosphinylidyne-containing amine group are introduced
The characteristic of the macropore is formed to meet.The mesoporous of concentration of the invention derives from sol gel network, enriches and perforation is big
Hole derives from solid-liquid two-phase laminated flow caused by polyethylene glycol.Pass through the addition of amide substance, the sol-gel mistake of regulation system
Journey produces sol-gel system more evenly, to obtain more evenly after baking, that is, has mesoporous point more concentrated
Cloth gel rubber material.
On the basis of above-mentioned formation mesoporous gel, polyethylene glycol is also more evenly fine and closely woven in distribution wherein.With pyridine plus
Enter, pH is improved in reaction system, and the organic compound of phosphinylidyne-containing amine group will release a certain amount of ammonia, and make the alkalinity of system liquid phase
Effect is more significant, and under alkaline environment, the polyethylene glycol in liquid phase becomes relative constriction state from opposite extended position, then its
Pore range in space can reduce, generate the relatively small and more macropore in aperture, these increase significantly relative small size it is big
Hole is mutually communicated, and low-carbon alcohols or low carbon alcohol solution is used to impregnate to remove the liquid phases such as polyethylene glycol, such stoste phase after aging
The space occupied becomes the duct that macroporous aluminium oxide is mutually communicated, and former solid fraction constitutes macropore hole wall, improves aluminium oxide
Porosity, while in subsequent drying and roasting process, the pore structure of aluminium oxide can be good at keeping.
Sol-gel process of the present invention due to introducing the adjustable system of phosphinylidyne-containing amine group, generates colloidal sol more evenly
Gel rubber system can make the reduction of Solid-Liquid Separation degree, to accordingly reduce the aperture of macropore.Said effect can be dry in normal pressure
There is uniform stress distribution when dry, roasting, keep the integrality of macropore, avoid the broken of material, be conducive to improve material
Whole mechanical strength.Ageing step of the invention uses higher alcohol-water mixture and higher aging temperature, can make gel particles
Hydration reaction occurs for son, enhances interparticle bond strength, and in constant pressure and dry, roasting, system is substantially shunk, consistency
It is opposite to improve, thus can be further improved mechanical strength.
In present invention process, the flue gas mainly includes coal-fired plant flue gas, FCC regenerated flue gas, refinery processes furnace
Flue gas or chemical industry kiln gas (such as cracking of ethylene kiln gas) etc..Flue gas mainly contains NOx, SOx and impurity, wherein described
Impurity is generally dust, water, CO2And O2Deng wherein the concentration of NOx is generally 700 ~ 4500mg/Nm3, the concentration of SOx is generally
700~4500mg/Nm3;Temperature into the low-temperature flue gas of Benitration reactor is 150 ~ 260 DEG C, preferably 180~240 DEG C.
In present invention process, the flue gas flow rate is 2~15m/s, preferably 4 ~ 10m/s;The denitration reaction residence time is
0.5~20s.
In present invention process, in the gaseous mixture containing ammonia of ammonia-spraying grid filling, NOx in ammonia and flue gas and
The total moles ratio of SOx is 0.9:1 ~ 1.15:1.
In present invention process, the gaseous mixture containing ammonia is the mixture of ammonia and air, and wherein ammonia is mixed
Closing the volumetric concentration in gas is 0.5% ~ 10%.In the method for the present invention, the conveyer belt uses conventional metal net shaped conveyer belt,
It is preferred that stainless steel mesh conveyer belt, conveyer belt mesh size guarantees to be less than catalyst particle size, to guarantee catalyst granules not
It is fallen from mesh, generally 0.1~3mm, preferably 1.5~2.5mm;Conveyer belt uses external motor driven, is driven by conveyer belt
Driving wheel drives conveyer belt rotation.
In present invention process, piling height is 50~500mm to the microspheroidal denitrating catalyst on a moving belt, preferably
200~300mm.
In present invention process, the conveyer belt transmission speed is 0.1mm/s~10mm/s, preferably 0.5~2mm/s.
In present invention process, the conveyer belt number of plies and width can according to actual needs and reactor size is selected
It selects, preferably 3~10 layers of the conveyer belt number of plies, more preferable 3~8 layers, conveyor width is limited with not brushing up against wall of reactor, conveyer belt
Width direction and wall of reactor gap are 2 ~ 50mm, preferably 2 ~ 5mm.
In present invention process, vertical range between the adjacent two layers conveyer belt is 1200 ~ 2000mm, preferably 1400
~1600mm。
In present invention process, the catalyst in catalyst hooper is fallen into, mortgage originator is filled into first layer after stripping
The circulation of conveyer belt completion catalyst.
In present invention process, the stripping carries out in stripper, stripping process are as follows: low pressure steam is by following logical
Enter, is stained with the catalyst of ammonium salt by being passed through above, is taken out of the ammonium salt gasification in catalyst using low pressure steam, ammonium salt gas
Change to decompose and obtains SO2、NH3、H2O etc., gaseous mixture enter condenser and react to ammonium salt solution.
Compared with prior art, present invention process has the advantage that
(1) in present invention process, for NOx and SOx directly with the mixing solid/liquid/gas reactions containing ammonia, NOx is reduced to N in flue gas2, SOx
Ammonium salt is directly generated, ammonium salt is to have sticking liquid at this temperature, is adhered on catalyst, the dust in flue gas is with ammonium
Salt is adhered on catalyst granules together, and reaction system is left together with catalyst granules, is achieved the effect that while dedusting, is taken off
Nitre, desulfurization and dedusting can be completed in a reactor, reduce follow-up process, reduce investment and operating cost, use simultaneously
Low-temp reaction reduces energy consumption and the requirement to equipment.The present invention has the dust in flue gas using micro-spherical catalyst bed
Filtration has better capture effect for the dust less than 1 micron due to containing dual pore size distribution in its catalyst,
It is not easy to block.
(2) mobile catalyst bed is formed using conveyer belt in the present invention, the ammonium salt of generation is adhered to catalyst granules
On, reaction system is left together with catalyst granules, is avoided the problem of the escaping of ammonia causes ammonium hydrogen sulfate to block bed, is extended
The cycle of operation of device;
(3) present invention process can adjust residence time of the catalyst in reactor by adjusting the movement velocity of conveyer belt,
By adjusting the bed height of catalyst on conveyer belt, reaction time of the flue gas by catalyst bed is adjusted, therefore can locate
The flue gas for managing different NOx and SOx concentration is more suitable for the FCC regenerated flue gas of high NOx concentration;
(4) catalyst circulation uses in the present invention, and the return into after ammonium salt is stripped off excessively of the catalyst after reaction is filled into first
The reaction was continued for layer conveyer belt, can substantially reduce the dosage of catalyst, while the ammonium salt that stripping obtains can be used as denitration reaction
Byproduct.
Detailed description of the invention
The schematic diagram of denitrating technique and reactor Fig. 1 of the invention.
1, flue gas, 2, the gaseous mixture containing ammonia, 3, catalyst granules, 4, purified gas, 5, stripping gas, 6, ammonium salt steam,
7, ammonium salt solution, 8, ammonia-spraying grid, 9, catalyst addition pipe, 10, conveyer belt, 11, belt-driven wheel, 12, catalyst discharge
Pipe, 13, catalyst hooper, 14, reactor inner cylinder, 15, shell of reactor, 16, stripper, 17, condenser.
The stereoscan photograph of 1 catalyst of Fig. 2 the embodiment of the present invention.
Specific embodiment
It elaborates, but is not intended to limit the present invention to the method for the present invention below by specific embodiment.The hole
Distribution and porosity with mercury injection method by being characterized, and mechanical strength is characterized with side pressure breaking strength, using Dalian device diagnostic device
II Intelligent testing machine for particle of the ZQJ- measurement of factory's production.
Present invention simultaneously provides a kind of Benitration reactors, including condenser 17, stripper 16, shell of reactor 15, reaction
Pipe 9, conveyer belt 10, belt-driven wheel 11, catalyst exit line 12 and catalysis is added in device inner cylinder 14, ammonia-spraying grid 8, catalyst
Agent hopper 13;It is wherein reactor external seal chamber between shell of reactor 15 and reactor inner cylinder 14, belt-driven wheel 11 exists
Reactor external seal is intracavitary, and conveyer belt 10 is attached on belt-driven wheel 11, crosses reactor inner cylinder 14, and pipe 9 is added in catalyst
In reactor external seal top of chamber, 9 outlet at bottom face conveyer belt one end of pipe is added in catalyst, and catalyst hooper 13 is in reactor
External seal bottom of chamber portion, catalyst exit line 12 connect in 13 bottom of catalyst hooper, 12 outlet at bottom face vapour of catalyst exit line
Device 16 is mentioned, 16 solid outlet of stripper connects catalyst and pipe 9 is added, and the gas vent of stripper connects condenser 17.
The operating process of Benitration reactor of the invention is as follows: microspheroidal denitrating catalyst 3 is added pipe 9 by catalyst and adds
It infuses accumulation on first layer conveyer belt 10 and forms bed, belt-driven wheel 11 drives the bed movement on conveyer belt 10, bed
It is fallen on next conveyer belt under the effect of gravity across reactor inner cylinder 14 into reactor external seal chamber, forms bed,
And moved in the opposite direction under the driving of belt-driven wheel 11, according to the above-mentioned method of operation, formation is continuously run
Conveyer belt bed;Flue gas 1 enters from reactor bottom, and the gaseous mixture 2 containing ammonia is filled into flue gas 1 by ammonia-spraying grid 8,
Air-flow passes through the staggered catalyst bed of multiple-layer horizontal from top to bottom, carries out denitration desulphurization reaction, removes NOx and SOx, together
Shi Fenchen is discharged with the purified gas 4 on catalyst granules, obtained from reactor bottom with ammonium salt adherency, and catalyst is in the last layer
The end of conveyer belt 10 falls into catalyst hooper 13, enters stripper 16 via catalyst exit line 12, the ammonium salt being stripped off steams
Vapour 6 obtains ammonium salt solution 7 by the condensation of condenser 17, and catalyst granules after stripping, which returns to catalyst pipe 9 is added, is filled into the
Circulation is completed on one layer of conveyer belt 10.
Embodiment 1
Water, dehydrated alcohol, aluminium chloride, polyethylene glycol, formamide are uniformly mixed by (20 DEG C) at room temperature, add pyridine, mixing
By weight, content is respectively as follows: water 23%, ethyl alcohol 22%, aluminium chloride 20%, polyethylene glycol (viscosity average molecular weigh 1,000,000) to object each component
0.3%, formamide 1%, pyridine 33.7%.After being uniformly mixed, resulting mixture is added drop-wise in 20 ~ 50 DEG C of oil column and is shaped to
Microspheroidal aging 48 hours at 45 DEG C, then with mixture 48 hours after the mixed liquid dipping aging of ethyl alcohol and water, has been impregnated
After finishing and removing liquid phase, the drying at 40 DEG C is until apparent loss of weight no longer occurs for product.Then it roasts 6 hours, obtains at 600 DEG C
To alumina microsphere carrier;With the maceration extract incipient impregnation alumina support containing ferric nitrate and manganese nitrate, then at 80 DEG C
8 hours dry, 550 DEG C roast 6 hours, are cooled to room temperature, obtain microspheroidal denitrating catalyst A.
MnO2Content is 10wt%, Fe2O3Content is 5wt%, overall porosity 80%, and hole has dual pore size distribution, wherein
Macropore be evenly distributed, macropore average pore size 360nm, macro porosity led accounts for 55%;4 ~ 6nm of mesoporous pore size, mesoporous porosity account for
24%.Side pressure strength 7.1N/mm, BET specific surface area 160m2/ g, Kong Rongwei 0.51cm3/g.Through big known to scanning electron microscopic observation
Hole has three-dimensional connectivity.
Embodiment 2
Water, dehydrated alcohol, aluminium chloride, polyethylene glycol, formamide are uniformly mixed by (20 DEG C) at room temperature, add pyridine, mixing
By weight, content is respectively as follows: water 31%, ethyl alcohol 29%, aluminium chloride 16%, polyethylene glycol (viscosity average molecular weigh 2,000,000) to object each component
0.5%, formamide 3.5%, pyridine 20%.After being uniformly mixed, resulting mixture is added drop-wise in 20 ~ 50 DEG C of oil column and is shaped to
Microspheroidal aging 24 hours at 60 DEG C, is then impregnated mixture 48 hours after aging with ethyl alcohol, immersion finishes and removes liquid phase
Afterwards, it is dried at 50 DEG C until apparent loss of weight no longer occurs for product.Then it is roasted 5 hours at 750 DEG C, obtains microballoon oxidation
Alumina supporter;It is then 5 hours dry at 100 DEG C with the maceration extract incipient impregnation alumina support containing ferric nitrate and manganese nitrate,
550 DEG C roast 5 hours, are cooled to room temperature, obtain microspheroidal denitrating catalyst B.
MnO2Content is 8wt%, Fe2O3Content is 12wt%, overall porosity 73%, and hole has dual pore size distribution, wherein
Macropore be evenly distributed, macropore average pore size 180nm, macro porosity led accounts for 47%;7 ~ 11nm of mesoporous pore size, mesoporous porosity account for
31%.Side pressure strength 8.9N/mm.BET specific surface area is 155 m2/ g, Kong Rongwei 0.61cm3/g.Through big known to scanning electron microscopic observation
Hole has three-dimensional connectivity.
Comparative example 1
This example compares with embodiment 1.The difference is that being added without formamide.Average 4.6 μm of diameter macropores, porosity 45%, macropore
Porosity accounts for 13%.Pore-size distribution: mesoporous 4-20nm, 3.1 ~ 7.9 μm of macropore.Side pressure strength 1.3N/mm.Resulting materials BET compares table
Area is 115 m20.4 cm of/g, Kong Rongwei3/g.It is essentially through macropore known to scanning electron microscopic observation isolated, big pore size distribution is not yet
Too uniformly.
Embodiment 3
FCC regenerated flue gas flow is 150,000 Nm3/ h, temperature are 650 DEG C, pressure 10kPa, NOx concentration 600mg/Nm3, SO2
Concentration is 1000mg/Nm3, SO3Concentration is 20mg/Nm3, dust content 200mg/Nm3.NOx emission standard is 200 mg/Nm3。
Catalyst uses microspheroidal denitrating catalyst A.
FCC regenerated flue gas takes heat by boiler first, and temperature is reduced to 200 DEG C of reaction temperature by 650 DEG C, contains ammonia
Mixed gas flow is 1800Nm3/ h, wherein ammonia volume fraction is 4%, and stripping gas 0.8MPa, 420 DEG C of overheated steam steam
Vapour, flow 15Nm3/h.The present embodiment uses movable reactor, the interior seal chamber size of reactor be long 8m × wide 6m ×
High 8m;Reaction time is 0.5s, and 3 layers of conveyer belt are arranged, and catalyst bed layer height is 300mm on each conveyer belt, transmits mark
Very little is long 9m × wide 5.8m, selects stainless steel mesh conveyer belt, and aperture diameter 3mm drives wheel diameter 300mm, upper layer and lower layer
Outage 1300mm between conveyer belt, there are enough space for maintenances.After reaction, it is ensured that the NOx content of purifying smoke is
100mg/Nm3, SO2Content is 25mg/Nm3, dust content is less than 10mg/ Nm3, meet the environmental requirement of priority control area, cigarette
Gas can pass through smoke stack emission.
Embodiment 4
FCC regenerated flue gas flow, temperature, pressure are the same as embodiment 1, NOx concentration 2000mg/Nm3, SO2Concentration is 2000mg/
Nm3, SO3Concentration is 200mg/Nm3, dust content 400mg/Nm3.NOx emission standard is 100 mg/Nm3。
Catalyst uses microspheroidal denitrating catalyst B.
FCC regenerated flue gas takes heat by boiler first, and temperature is reduced to 200 DEG C of SCR denitration reaction temperature by 650 DEG C;Contain
The mixed gas flow for having ammonia is 1600Nm3/ h, wherein ammonia volume fraction is 3%, stripping gas 0.8MPa, 420 DEG C of overheat
Vapor steam, flow 15Nm3/h;The interior seal chamber size of reactor is long 8m × wide 6m × high 15m;Reaction time is
10 layers of conveyer belt are arranged in 2s, and catalyst bed layer height is 500mm on each conveyer belt, conveyer belt having a size of long 9m × wide 5.8m,
Stainless steel mesh conveyer belt is selected, aperture diameter 3mm drives wheel diameter 300mm, outage between upper layer and lower layer conveyer belt
1500mm, there are enough space for maintenances.After reaction, it is ensured that the NOx content of purifying smoke is 100mg/Nm3, SO2Contain
Amount is 30mg/Nm3, dust content is less than 10mg/ Nm3, meet the environmental requirement of priority control area, flue gas can be arranged by chimney
It puts.
Comparative example 2
With embodiment 1, only reactor replaces with traditional fixed bed reactors, and catalyst uses commercially available vanadium tungsten titanium honeycomb
Catalyst, group are divided into component known in the art, are loaded using modularization, and single catalyst module height is 1m, reactor
Size is 4.4m × 4.6m, and three layers of Catalyst packing, FCC regenerated flue gas first takes heat by boiler, and temperature is reduced to by 650 DEG C
200 DEG C of SCR denitration reaction temperature;The mixed gas flow containing ammonia that raw material drainage area provides is 1600Nm3/ h, wherein ammonia
Concentration is 3v%.Gaseous mixture containing ammonia is added in the upstream flue apart from reactor inlet certain distance, by ammonia-spraying grid
Mixing diffusion after, guarantee reactor inlet flue gas in ammonia concentration deviation less than 5%, enter back into SCR reactor reaction, pass through
After crossing denitration reaction, it is ensured that the NOx content of purifying smoke is 100mg/Nm3, the flue gas after denitration goes successively to downstream unit
It is exchanged heat, desulfurization and dedusting, meets the environmental requirement of priority control area.
Comparative example 3
Still using the reactor in comparative example 1, flue gas composition guarantees that ammonia is escaped since NOx concentration is too big in flue gas with embodiment 2
Escape ﹤ 3mgNm3, NOx concentration is 1000 ~ 1300mg/Nm after denitration3, it is unable to qualified discharge, and dust still needs to enter desulfurization and dedusting
System is handled.
Comparative example 4
With embodiment 2, only reactor replaces with traditional fixed bed reactors, guarantees that the NOx content of purifying smoke is up to standard.
Comparative example 5
With embodiment 4, only reactor replaces with the moving-burden bed reactor in CN102008893A.Select partial size be 2.5 ~
The catalyst of 7.5mm, catalyst shape are graininess, short cylinder or honeycomb etc., and group is divided into component known in the art,
Circulation total amount is 40m3, reactor size is 4.4m × 4.6m, the NH of addition3Molar ratio with NOx in flue gas is 1:1, and mixing is equal
It is even latter and enter Catalytic Layer, it removes the flue gas of NOx and is discharged from top.After denitration reaction, it is ensured that the NOx of purifying smoke
Content is 100mg/Nm3, the flue gas after denitration go successively to downstream unit exchanged heat, desulfurization and dedusting, with meeting priority control
Area's environmental requirement.The cycle of operation of embodiment and comparative example, catalyst amount and clean-up effect are shown in Table 1.
1 embodiment of table and the comparative example cycle of operation, catalyst amount and clean-up effect compare.