CN108480157A - One kind urging cracking unit desulphurization denitration inner wall of tower anticorrosion composite membrane and its implementation - Google Patents
One kind urging cracking unit desulphurization denitration inner wall of tower anticorrosion composite membrane and its implementation Download PDFInfo
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05D1/00—Processes for applying liquids or other fluent materials
- B05D1/36—Successively applying liquids or other fluent materials, e.g. without intermediate treatment
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- 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
- B01D53/46—Removing components of defined structure
- B01D53/60—Simultaneously removing sulfur oxides and nitrogen oxides
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- 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
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- B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05D3/00—Pretreatment of surfaces to which liquids or other fluent materials are to be applied; After-treatment of applied coatings, e.g. intermediate treating of an applied coating preparatory to subsequent applications of liquids or other fluent materials
- B05D3/12—Pretreatment of surfaces to which liquids or other fluent materials are to be applied; After-treatment of applied coatings, e.g. intermediate treating of an applied coating preparatory to subsequent applications of liquids or other fluent materials by mechanical means
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2258/00—Sources of waste gases
- B01D2258/02—Other waste gases
- B01D2258/0283—Flue gases
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
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Abstract
One kind urging cracking unit desulphurization denitration inner wall of tower anticorrosion composite membrane and its implementation, composition adjusts II type of paint by II type of FS300 nanofiber desulfurization priming paint, FD300 nanometer desulfuration current potentials, complex method first sprays II type of FS300 nanofiber desulfurization priming paint 8 10 times in bottom, 600 μm of thickness of dry film.Surface spraying FD300 nanometer desulfuration current potentials adjust II type of paint 1 time, and 80 μm of thickness of dry film, material itself has excellent environment-friendly function without heavy metals such as Zn, Cr, Pb；The material is novel high-tech environment-friendly materials; it is nontoxic, harmless, tasteless, environmentally friendly; protect construction personnel's health; the key technical indexes reaches and considerably beyond national standard after surface treatment; it can effectively solve the problem that petrochemical industry catalytic cracking unit desulphurization denitration inner wall of tower anticorrosion problem, application range are wide；And repair coating is convenient, can compare far from enamel, plating, and the coating of very thin only part millimeters thick effectively plays etch-proof effect really.
Description
Technical field
The present invention relates to coating construction methods, and in particular to one kind urges cracking unit desulphurization denitration inner wall of tower anticorrosion compound
Film and its implementation.
Background technology
Further to implement State Council《The comprehensive programme of work of energy-saving and emission-reduction》And《Energy-saving and emission-reduction statistical monitoring and examination are real
Apply scheme and method》, improve the operational efficiency and management level of desulphurization denitration facility, it is ensured that realize that Eleventh Five-Year Plan sulfur dioxide is total
Emission reduction targets are measured, reinforce the supervision to desulphurization denitration facility operation process conscientiously, reinforce operation, the dimension of desulphurization denitration facility conscientiously
Shield and management, it is ensured that the normal operation and denitrification efficiency of desulphurization denitration facility solve catalytic cracking unit high-efficiency tobacco qi exhaustion
Sulphur denitrating tower Anticorrosion Problems are particularly important.
In recent years, with increasing for high Sulphureous acidiferous crude oil is processed, the equipment etching problem exposure of catalytic cracking unit is non-
Chang Yanchong, the stable operation for correctly recognizing and the etching problem of catalytic unit being prevented to be directly related to device.
Catalytic cracking is the effect by catalyst, under the conditions of certain temperature and pressure, makes feedstock oil by a series of
Chemical reaction, cracking as light-end products process.Catalytically cracked stock be heavy distillate and heavy oil (reduced crude,
Decompression residuum), wherein containing the metals such as nonhydrocarbons element and Ni-V-Fe, calcium, sodium such as carbon, protium and more sulphur, nitrogen, oxygen
Element.In process of production, a part is transferred in product, catalyst and technique waste water for nonhydrocarbon element and metallic element, one
Divide and is discharged into atmospheric environment by flue gas and catalyst dust.
Catalytic cracking unit flue gas desulfurization and denitrification equipment, design temperature：62 degrees Celsius, operating pressure：2.6 kPas, liquid
Flow velocity：20-25m/sec, solid content：5000mg/L, pH value：Normal condition 6.5, emergency are less than 4；It is straight in the middle part of desulfurizing tower
The entrance that 2.8 meters of diameter, as liquid inlet, which is gas attack, is liquid corrosion below and is washed away position,
The region flow rate of liquid is big, and solid content is high, and scouring force is strong.
Atmosphere pollution is mainly compound, nitrogen compound, carbon monoxide and the catalyst powder of the sulphur in regenerated flue gas
Dirt.Catalytic cracking flue gas contains a large amount of SOX, NOX, particulate matter and CO etc., has become important air pollution source.Oil plant
The SOX of discharge accounts for about the 6%~7% of its total release, and the SOX of catalytic cracking unit discharge just accounts for 5% or so.
The catalytic cracking flue gas discharge standard in the U.S. be often burning 1000kg coke allow discharge 25g sulfur dioxide and
1kg particles.
The standard limit of smog release in Europe is that newly-built catalytic cracking unit SO 2 from fume concentration of emission is 20~150mg/
M3, granule content are 10~30mgm3.
Catalytic cracking flue gas feature The Waste Heat Boiler of Catalytic Cracking Units flue gas is flue gas and temperature of the dust-laden containing SO2 and SO3
High (180~240 DEG C of normal temperature, temperature is up to 500 DEG C when highest).
Dust contained flue gas fluctuation is big, flows speed soon, big to inner wall erosive wear.
Smaller (after three rotations or four cyclone dust removals, 0~5 μm of grain size accounts for 75%) and hard flue dust particle diameter distribution in flue gas
Degree is big (sieve and silica-sesquioxide catalyst).
Normal operating temperature is between 50~100 DEG C inside catalytic cracking and desulfurizing denitrating tower, and temperature reduces, smoke moisture
It greatly increases；Simultaneously because the acid dew-point temperature of flue gas reduces, inner wall easily condenses, shape after remaining SO3NOX dissolvings in flue gas
At corrosivity, the very strong dilute sulfuric acid solution of permeability, very strong corrosivity is caused to catalytic cracking and desulfurizing denitration tower structure.It is using
Catalytic cracking and desulfurizing denitrating tower outside cylinder wall is found in the process there are the different degrees of leakage phenomenon in many places, and sepage is on stack shell surface
Crystallization is formed, winter forms bulk icicle.Catalytic cracking and desulfurizing denitrating tower coated inside has lost anti-corrosion effect, and Fig. 1 is to urge
Change cracking desulfurization denitrating tower inner wall corrosion situation.
One, desulphurization denitration anti-corrosion means and problems faced are commonly used
From the point of view of present situation, the technological means of catalytic cracking and desulfurizing denitrating tower inner wall corrosion can be effectively prevent very limited,
Common method includes：Poly- urine, acid resistant adhesive mortar and glass flake, stainless steel inner lining, titanium alloy liner etc.；From actual use for many years
Situation, the anti-corrosion time that used anti-corrosion means can play were very limited, it is virtually impossible to more than 1 year, in practice it has proved that titanium closes
Golden liner can not be used for a long time under acidic environment.
The reason of causing current anti-corrosion means that can not obtain promising result includes mainly following three aspects：
(1) corrosive medium complicated component：There are water vapour, sulfur dioxide, sulfur trioxide, titanium dioxide in catalytic cracking and desulfurizing denitrating tower
Nitrogen, fluoride and chloride etc., the strong corrosive medias such as dilute sulfuric acid, dust technology, diluted hydrofluoric acid, dilute hydrochloric acid formed with water are molten
The dilute sulfuric acid solution formed after solution passes through gap, is formed and is corroded to inner wall of tower, and penetrate chimney wall quickly, causes serious safety
Hidden danger；
(2) it is run inside tower due to being in damp and hot acidic environment for a long time after catalytic cracking and desulfurizing denitration, traditional inside is anti-
Rotten layer cannot resist the corrosion under the environment and occur coating leakage, fall off damage, cause its inner wall anti-corrosive layer to lose anti-corrosion work(
Energy.
(3) poor adhesive force of anti-corrosion material and catalytic cracking inner wall, permeability resistance is low, causes acid accumulator penetration to base material, hair
Life corrodes and fails and fall off.
(4) catalytic cracking and desulfurizing denitrating tower corrosion is made not only into huge direct economic loss and the wasting of resources, Er Qieshi
The direct risk factor of serious accident.
Two, the meaning studied
The corrosion of catalytic cracking and desulfurizing denitrating tower is made not only at huge direct economic loss and the wasting of resources, but also is considerable safety
The direct risk factor of accident, seriously affects the safe operation of equipment.The research of the method and material that prevent corrosion of metal is not only
It is a great problem in science, and plays an important role in national economy and status.The developing water of heavy anticorrosive material
It is flat how, performance is how, it has also become one of the mark of mark one national science technical merit.Further to implement State Council
《The comprehensive programme of work of energy-saving and emission-reduction》And《Energy-saving and emission-reduction statistical monitoring and examination embodiment and method》, improve desulphurization denitration
The operational efficiency and management level of equipment, it is ensured that realize Eleventh Five-Year Plan total sulfur dioxide emission reduction targets, reinforce conscientiously to desulfurization
The supervision of denitration facility operation process, it is ensured that the safe normal operation and desulfuration efficiency of desulphurization denitration facility, for using efficient
Flue gas desulfurization and denitrification system is particularly important.
Invention content
In order to overcome the above-mentioned deficiencies of the prior art, the object of the present invention is to provide one kind urging cracking unit desulphurization denitration tower
Inner wall anti-corrosive composite membrane and its implementation make it have the corrosion of the acidproof, alkaline-resisting of overlength, salt tolerant, water vapour and nuisance
Ability reduces composite bed thickness, improves the ageing resistance of material, has the function of unprecedented high-performance anticorrosion ability and steady
It is qualitative, it is nontoxic, harmless, tasteless, environmentally friendly, protect a kind of desulphurization denitration inner wall of tower anticorrosion composite wood of construction personnel's health
Feed composition.
In order to overcome the shortage of prior art, the technical scheme is that solve in this way：
One kind urging cracking unit desulphurization denitration inner wall of tower anticorrosion composite membrane, II type of the FS300 nanofiber desulfurization priming paint way bottom of to
600 μm of the dry film overall thickness of II type of layer 8~10, FS300 nanofiber desulfurization priming paint, FD300 nanometer desulfuration current potentials adjust paint
II type way is to surface 1,80 μm of dry film overall thickness, the bottom FS300 nanometer desulfurations priming paint II types with surface FD300 nanometers
Desulfurization current potential adjusts 680 μm of the dry film overall thickness of II type of paint.
Described II type of FS300 nanofibers desulfurization priming paint, FD300 nanometer desulfuration current potentials adjust II type of paint by Xi'an Hua Jieao
Extra large new material company production, wherein II type of desulfurization priming paint, nanometer desulfuration current potential adjust II type by specification of paint and prepare.
One kind urging cracking unit desulphurization denitration inner wall of tower anticorrosion composite membrane implementation, includes the following steps：
Pre-processing：
1) high-lift operation hanging cradle is built as construction tool；
2) surface sand-blasting process is carried out to inner wall of tower surface substrate, abrasive material uses copper ore, forbids to carry out operation using river sand；
3) abrasive blasting derusting reaches Sa3 grades, or reaches St3 grades using power tool polishing derusting；
4) construction surface requirements are clean, dry；All macroscopic greases, oil, dirt, lubricant and other pollutants must be complete
Portion removes；
5) desulphurization denitration inner wall of tower remains clean and tidy, clean；Repeatability must to be carried out to construction surface clear before per pass paint application
It is clean, keep ventilation, inner wall to keep dry state；
Composite membrane is implemented：
1) reach construction surface requirements in surface cleaning state, smear first of FS300 nanometer desulfurations priming paint (II), thickness of dry film
60 μm, from inner wall of tower top to bottom application and there cannot be holiday defect, abutment joint region carries out pre-coating；
2) after first of coating surface is done something in disregard of obstacles, application second FS300 nanometer desulfurations are carried out from top to bottom using spraying equipment
Priming paint (II), 80 μm of thickness of dry film；
3) after second coating surface is done something in disregard of obstacles, application third road FS300 nanometer desulfurations are carried out from top to bottom using spraying equipment
Priming paint (II), 80 μm of thickness of dry film；
4) after coating surface is done something in disregard of obstacles after third road, the 4th FS300 nanometer desulfurations of application are carried out from top to bottom using spraying equipment
Priming paint (II), 80 μm of thickness of dry film；
5) after the 4th coating surface is done something in disregard of obstacles, the 5th FS300 nanometer desulfurations of application are carried out from top to bottom using spraying equipment
Priming paint (II), 80 μm of thickness of dry film；
6) after the 5th coating surface is done something in disregard of obstacles, the 6th FS300 nanometer desulfurations of application are carried out from top to bottom using spraying equipment
Priming paint (II), 80 μm of thickness of dry film；
7) after the 6th coating surface is done something in disregard of obstacles, the 7th FS300 nanometer desulfurations of application are carried out from top to bottom using spraying equipment
Priming paint (II), 80 μm of thickness of dry film；
8) after the 7th coating surface is done something in disregard of obstacles, the 8th FS300 nanometer desulfurations of application are carried out from top to bottom using spraying equipment
Priming paint (II), 80 μm of thickness of dry film；
9) after the 8th coating surface is done something in disregard of obstacles, the 9th FD300 nanometer desulfurations of application are carried out from top to bottom using spraying equipment
Current potential adjusts II type of paint, 80 μm of thickness of dry film；
10) it after the 9th coating surface is done something in disregard of obstacles, carries out routine examination to entire compound layer surface, nine application process dry films are total
680 μm of thickness answers timely processing, entire coat system to must satisfy coating process check criteria, repair coating defect problems
It must dry 7-10 days under the environmental condition divulged information or heated after benefit, routinely be checked again, it is ensured that after qualified
It can put into production use.
Described composite membrane can form fine and close intercommunication interpenetrating conductive network structure, and corrosion of metal current potential is made to increase
223mv, 173.2 μ A/cm of the close decline of corrosion current2, corrosion electric current density substantially reduces, and the condition and difficulty for so that corrosion is occurred carry
Height, while the adhesive force >=22MP of the composite membrane and base material steela, chloride permeability rate (mg/cm2.d)≤3.6×10-5, this is multiple
Film elongation at break is closed, the maximum displacement value being more than under base material limiting temperature situation, elongation at break 62.9%.
The effect of the present invention：
1. through large sizes such as sinopec Guangzhou Branch catalytic cracking and desulfurizing denitration equipment, BP companies of Britain desulphurization denitration TPA equipments
Major project actually uses verification more 2 years, efficiently solve the Anticorrosion Problems under desulphurization denitration harsh environment, Guangzhou
Branch company's project is proved to be successful has played the good exemplary role of industry, Guangzhou Branch catalytic cracking and desulfurizing denitration dress in sinopec
Standby successful operation, and win the great Innovation Awards of sinopec in 2016.BP companies of Britain successfully use, and solve world chemical industry TPA
The problem for equipping corrosion, the gate of international market is opened for company, and international other major companies also negotiate to prepare to use with us
This achievement.
Nanofiber high-performance heavy antisepsis 2. " metallo-plastic " cylinder composite technology index
1. it is as follows that FS300 nanometer desulfurations priming paint (II types), FD300 nanometer desulfuration current potentials adjust paint (II types) main performance index
Table：
2. anti-leakage, extension at break require：
| Project | Index |
| Chloride permeability rate (mg/cm2.d)≤ | 3.6×10-9 |
| Elongation at break (%) >= | 62.9 |
Description of the drawings
Fig. 1 is catalytic cracking and desulfurizing denitrating tower inner wall corrosion situation.
Fig. 2 is corrosion pit datagram.
Specific implementation mode
The present invention is further discussed below with reference to embodiments.
One kind urging cracking unit desulphurization denitration inner wall of tower anticorrosion composite membrane, II type of FS300 nanofiber desulfurization priming paint way
To bottom 8~10,600 μm of the dry film overall thickness of II type of FS300 nanofiber desulfurization priming paint, FD300 nanometer desulfuration current potential tune
Section II type of paint way to surface 1,80 μm of dry film overall thickness, the bottom FS300 nanometer desulfurations priming paint II types and surface
FD300 nanometer desulfuration current potentials adjust 680 μm of the dry film overall thickness of II type of paint：
One kind urging cracking unit desulphurization denitration inner wall of tower anticorrosion composite membrane implementation, includes the following steps：
Pre-processing：
1) high-lift operation hanging cradle is built as construction tool；
2) surface sand-blasting process is carried out to inner wall of tower surface substrate, abrasive material uses copper ore, forbids to carry out operation using river sand；
3) abrasive blasting derusting reaches Sa3 grades, or reaches St3 grades using power tool polishing derusting；
4) construction surface requirements are clean, dry；All macroscopic greases, oil, dirt, lubricant and other pollutants must be complete
Portion removes；
5) desulphurization denitration inner wall of tower remains clean and tidy, clean；Repeatability must to be carried out to construction surface clear before per pass paint application
It is clean, keep ventilation, inner wall to keep dry state；
Composite membrane is implemented：
1) reach construction surface requirements in surface cleaning state, smear first of FS300 nanometer desulfurations priming paint (II), thickness of dry film
60 μm, from inner wall of tower top to bottom application and there cannot be holiday defect, abutment joint region carries out pre-coating；
2) after first of coating surface is done something in disregard of obstacles, application second FS300 nanometer desulfurations are carried out from top to bottom using spraying equipment
Priming paint (II), 80 μm of thickness of dry film；
3) after second coating surface is done something in disregard of obstacles, application third road FS300 nanometer desulfurations are carried out from top to bottom using spraying equipment
Priming paint (II), 80 μm of thickness of dry film；
4) after coating surface is done something in disregard of obstacles after third road, the 4th FS300 nanometer desulfurations of application are carried out from top to bottom using spraying equipment
Priming paint (II), 80 μm of thickness of dry film；
5) after the 4th coating surface is done something in disregard of obstacles, the 5th FS300 nanometer desulfurations of application are carried out from top to bottom using spraying equipment
Priming paint (II), 80 μm of thickness of dry film；
6) after the 5th coating surface is done something in disregard of obstacles, the 6th FS300 nanometer desulfurations of application are carried out from top to bottom using spraying equipment
Priming paint (II), 80 μm of thickness of dry film；
7) after the 6th coating surface is done something in disregard of obstacles, the 7th FS300 nanometer desulfurations of application are carried out from top to bottom using spraying equipment
Priming paint (II), 80 μm of thickness of dry film；
8) after the 7th coating surface is done something in disregard of obstacles, the 8th FS300 nanometer desulfurations of application are carried out from top to bottom using spraying equipment
Priming paint (II), 80 μm of thickness of dry film；
9) after the 8th coating surface is done something in disregard of obstacles, the 9th FD300 nanometer desulfurations of application are carried out from top to bottom using spraying equipment
Current potential adjusts II type of paint, 80 μm of thickness of dry film；
10) it after the 9th coating surface is done something in disregard of obstacles, carries out routine examination to entire compound layer surface, nine application process dry films are total
680 μm of thickness answers timely processing, entire coat system to must satisfy coating process check criteria, repair coating defect problems
It must dry 7-10 days under the environmental condition divulged information or heated after benefit, routinely be checked again, it is ensured that after qualified
It can put into production use.
Basic principle
Metal material surface is due to the chemistry or electrochemistry by surrounding medium (air, high temperature, fused salt, non-aqueous or water-bearing media)
Effect and the variation of generating state and be converted into cenotype, to make metal material by destruction, this phenomenon is referred to as metal
Corrosion.Metal erosion is a spontaneous process, and extremely serious.
Metal erosion can be divided into following several types：
1. electrochemical corrosion.Metal forms corrosion caused by battery in aqueous solution, is most important in anticorrosion field
Research object.
2. chemical attack.Such as the high-temperature oxydation of steel fire door, and anhydrous solution forms battery.
3. biological corrosion.Such as the bacterial corrosion of underground buried tube.
By its corrosion product type, metal erosion can be divided into following two again：
1. film-forming type.When such as alumina, aluminum oxide film is generated, the further oxidation of metal has been delayed in resistance.Metal is in slightly higher temperature
When reacted with the oxygen in air and generate oxidation film, when film layer is very thin, oxygen can readily penetrate through, oxidation make speed that film thickens with
Film thickness is unrelated and is constant.
2. not film-forming type.Such as steel plate is in brine, the Fe that anode generates2+It cannot form a film, must leave at anode on the spot
Meet the OH of cathode generation.Ion precipitation is at Fe (OH)2, then in outer layer it is oxidized to iron rust FeOOH or Fe203.nH20, Bu Neng
The further corrosion of close film barrier metal is generated on steel face.
Electrochemical corrosion can be summarized as following three points
1) it can only lead to that metal material destroys and externally cannot make the short-circuit primary battery of useful work in boundary.
2) chemical affinity of the power from corrosion reaction of corrosion cell effect.
3) in corrosion cell, it is necessary to which at least a kind of equilibrium potential of the cathodic reduction reaction of substance is higher than corrosion failure
Metal anodic solution reaction equilibrium potential.
In aqueous solution, due to the potential difference of different metal, battery can be generated.Even if in same metallic plate, due to its office
The difference of portion's internal stress, the difference of composition of weld line, concentration of electrolyte solutions be poor, difference in oxygen concentration etc. in temperature difference, solution, all can
It generates potential difference and causes to corrode.
By taking steel plate as an example, corrosion cell reaction is：
Anode：Fe→Fe2++2e
Fe2+→Fe3++e
3Fe2++4H20→Fe304+8H++2e
Cathode：2H++2e→2H→H2(evolving hydrogen reaction of acid solution)
02+4H++2e→2H20 (oxygen reduction reaction of acid solution)
02+2H20+4e → 40H (oxygen reduction reaction in neutral or alkaline medium)
Fe3++30H→Fe(0H)3(corrosion product)
It is most important reaction for anticorrosive coating in oxygen reduction reaction acid, neutral, in alkaline medium, general
The corrosion of air and marine environment belongs to such.Due to generating the OH of alkalinity at cathode position.Ion can make grease type, alkyd
Type paint film saponification is peeled off.In addition, because of the necessary aerobic participation of the reaction, and it is very low in seawater depths oxygen concentration, therefore metal erosion
Reaction is very slow.Daily some corrosion seen be since oxygen concentration difference causes, as under rivet, rusty scale it is inferior because oxygen supply is few
And become anode.Dew drop on steel plate, outer layer oxygen supply is more and forms cathode, and Central oxygen-supply is few and becomes anode, and corrosion pit is such as
Shown in Fig. 2.
The driving force of corrosion cell is two interelectrode potential difference △ E.So the corrosion current of the battery is represented by
Following formula：
R in formulaa--- anode resistance；
RcOne cathode resistor
Re--- electrolyte solution resistance；
Rw--- external circuit resistance.
Corrosion current is bigger, and corrosion rate is faster.
The protection of metal erosion
In order to reduce corrosion, corrosion current must be reduced, in original Ec-EeIn the case of constant, it is (excellent that resistance control S rj can be used
Good thick-layer paint film), anodic control (anodic passivity), cathodic control (retardance cathode reaction).Also can take have concurrently anodic control,
Resistance controls and the mixing of cathodic control control, carrys out control corrosion rate.
People take many measures to reduce the loss of corrosion, but so far still with organic coating be it is most effective, most economical,
Using most universal.Coating is a kind of chemical materials, coated on can protect it from the erosion of environment on object plane, while can simultaneously be assigned
Beautiful (such as car paint), livery (such as Chinese red of bay mechanical hazard component), camouflage (such as battlebus weapon), and apply
It fills easy for construction, it is not necessary to as enamel needs large-scale baker, plating to need the equipment such as electroplating bath, also only limited the use of in water not necessarily like cathodic protection
Under, underground submerge position.Coating object can be as big as bridge spanning the sea, drilling platforms, as low as bicycle, tin can etc., so using
Wide scope；And repair coating is convenient, can compare far from enamel, plating.The coating of very thin only part millimeters thick,
Really effectively play etch-proof effect.
In general, the coating of zinc-rich and crome metal, copper is traditional anti-corrosion of metal material, but these anti-corrosion of metal materials are in ring
Border protection, resource and cost etc. have certain limitation.Therefore, green, novel anticorrosion material at low cost tool are explored
There is considerable economic and social benefit.
Nano material refers to material of the characteristic size in 1-100nm ranges of material component.When the size of a particle is small
When to nanometer scale, its microstructure and properties be both different from the microsystem of atom, molecule, also different from display eigen
The bulky grain material meta system of property, but a transition system therebetween.Nanoparticle size is small, specific surface
Product is big, has very high surface energy, to have a significant impact to its chemical property.It is demonstrated experimentally that particle dispersion degree is increased to one
After determining degree, with the reduction of particle diameter, atomicity and the ratio of total atom number positioned at particle surface increased dramatically, and work as grain
When diameter is reduced to 5nm, surface atom proportion is up to 50%.Since surface atom number increases, atomicity is reduced in particle, is made
Electron energy level in energy band divides, the level spacing (1 × 12 after division-2-1×10-5eV).Nano material due to its from
Feature on body structure and there is small-size effect, surface-interface effect, quantum size effect and macro quanta tunnel effect,
Thus compared with the conventional material with component, there are many unusual performances in catalysis, optics, magnetism, mechanics etc., in weight
Good development prospect is shown in terms of anti-corrosion.
The invention uses the FS300 nanofiber desulfurization priming paint (II of Xi'an Hua Jie Sci.＆Tech Developing Co., Ltd.'s production
Type), to adjust paint (II type) be base material to FD300 nanometer desulfuration current potentials, base material contains multifunctional nano series macromolecular fibre material
Material, shape is in threadiness, 40~80nm of grain size, 2~3 μm of length, conductivity 13s/m.
In terms of weight antirust.Nanoparticle size is small, large specific surface area, has very high surface energy, the material can be with
Metal surface forms one layer of invisible binary interface protective film, which keeps metal positive under water or salting liquid effect
Pole is in purifying current potential, and metal surface can be made to form fine and close oxide passivation layer, has anodic protection effect, anodic protection
Afterwards, nano-macromolecule material serves as catalyst, to interfere metal to be oxidized to this chemical reaction of becoming rusty.Electronics first is drawn from metal,
Then it is passed in oxygen.The two steps can form one layer of pure-oxide to prevent corrosion.
Nanofiber high molecular material can form fine and close intercommunication interpenetrating conductive network structure, keep corrosion of metal electric
Position increases and (increases 223mv), 173.2 μ A/cm of the close decline of corrosion current2, corrosion electric current density substantially reduces, and corrosion is made to occur
Condition and difficulty improve, and corrosion is not susceptible to.
Due to forming fine and close intercommunication interpenetrating conductive network structure, electronics is moved to coating surface, redox reaction hair
Life is happened at metal surface in the outer surface of paint, so that reaction is formed with metal and is spatially separating, protects metal not rotten
Erosion.Multifunctional nano high molecular material, in preservation process, the advantage for having reversible oxidation ← → reduction characteristic, not being lost, anti-corrosion
Function was up to 50 years as long as；
Binary interface can substantially reduce the surface tension of metal material again simultaneously, and the surface energy of material is made to be reduced to 10~15mJ/
m3, reach material surface modifying, acid, alkali, salt, water vapour and nuisance be not easy it is Nian Jie with surface, make material surface have acid-proof,
The erosion of alkali, salt, water vapour and nuisance to metal surface, reaches the function of high-performance antirust, anti-corrosive；
Nano-high molecule fibrous material is highly stable to acid, alkali, salt, water vapour and nuisance, due to its big specific surface area and
Special geometry can form fine and close separation layer, can effectively obstruct acid, alkali, salt, water vapour and nuisance to metal watch
The erosion in face.Nanofiber high molecular material can form metallo-plastic with resin, and the characteristics such as the acidproof, alkaline-resisting of overlength, salt tolerant are
High-performance rush-resisting material of new generation, and the ageing resistance of coating is improved, make the big raising of the colour fasteness to sunlight of coating, coating can be made
Color keep is permanent bright-coloured constant, has unprecedented functional stabilization.
Designing central principle is：Using functions such as superpower acidproof, the alkaline-resisting, salt tolerants of nano anti-corrosive material, in desulphurization denitration
Inner wall of tower forms nanofiber high-performance heavy antisepsis " metallo-plastic " composite material, one is built by receiving in desulphurization denitration inner wall of tower
Flexibility " metallo-plastic " cylinder that rice heavy anticorrosive material is constituted, to effectively prevent corruption of the acidic liquid to desulphurization denitration inner wall of tower
Erosion.Lot of experimental data and engineering verification show：The appearance of this novel nano fiber anti-corrosion " metallo-plastic " cylinder composite material,
The pattern for changing current desulphurization denitration tower aseptic technic completely becomes the most effectual way for solving this problem.
Material itself has excellent environment-friendly function without heavy metals such as Zn, Cr, Pb；
The material is novel high-tech environment-friendly materials, nontoxic, harmless, tasteless, environmentally friendly, protects construction personnel's health.Surface
After processing the key technical indexes reach and considerably beyond：
Surface treatment requires
1) in order to ensure that coat system plays optimum performance, ground before treatment, need to first carry out pattern handling, by GB/T26935-
2011 standards first clean greasy dirt, cleaning and repairing welding and gas cutting defect with organic solvent, manual work are used to not downhand weld
Tool is polished and is modified, and break corner is removed.
2) before being surface-treated, all greases is removed, the comprehensive grinding process of angle grinder strip wire brush is used after dry.
3) after being surface-treated, surface dirt is removed with the methods of compressed air purging or vacuum cleaning, surface dirt is not low
The grade 3 as defined in ISO 8502-3.
4) substrate surface for preparing japanning after being surface-treated will clean, dry, without grease, keep roughness and clean-up performance
Until the construction of prime paint.
This project key technology
The selection of nanometer high-property anti-corrosion material, composite Materials Design.Whether material is non-to acid, alkali, salt, water vapour and nuisance
Often stablize, nanofiber high-performance heavy antisepsis " metallo-plastic " composite material can be formed, protect it from the erosion of environment, rises
To the key of iris action；Heavy antisepsis " metallo-plastic " composite layer can form fine and close intercommunication interpenetrating conductive network knot
Structure makes corrosion of metal current potential increase and (increase 223mv), 173.2 μ A/cm of the close decline of corrosion current2, corrosion electric current density is significantly
It reduces, the condition and difficulty for so that corrosion is occurred improve, and corrosion is not susceptible to.With anodic protection effect, after anodic protection, due to
Fine and close intercommunication interpenetrating conductive network structure is formed, electronics is moved to coating surface, and redox reaction is happened at the appearance of paint
Face, rather than it is happened at metal surface, so that reaction is formed with metal and be spatially separating, metal is protected not to be corroded.
1., realize heavy antisepsis " metallo-plastic " and composite layer and base material steel adhesive force >=22MPa, chloride permeability rate
(mg/cm2.d)≤3.6×10-5It is the pass of catalytic cracking unit smoke-gas wet desulfurization denitrating tower anticorrosion engineering long life anti corrosion
Key guarantee.
2., nanofiber heavy-duty anticorrosive " metallo-plastic " fracture of composite materials elongation, be more than base material limiting temperature situation under most
The elongation at break of big displacement value, nanofiber heavy-duty anticorrosive " metallo-plastic " composite material is 62.9%, considerably beyond base material
The novel anticorrosion system of maximum displacement value under limiting temperature situation, the design can meet desulfurization in catalytic cracking unit operation
The generated linear extendible of denitrating tower changes.
Compound success novel nano fiber heavy antisepsis " metallo-plastic " composite material of material innovation, has traditional material can not
The acid-resistant anti-corrosion performance of analogy is great innovation and anti-corrosion theory and the technology of catalytic cracking unit antisepsis composite material
Revolution can effectively solve the problem that the long-standing corrosion problem of petrochemical industry desulphurization denitration.
Principle innovation has anodic protection action principle, relatively has with traditional sacrificial anode and protective cathode antiseptic principle bright
Aobvious advantage can bear the corrosion of strong acid in desulphurization denitration tower.Nanofiber high-performance heavy antisepsis " metallo-plastic " composite material,
Flexibility " plastic-metal " cylinder being made of nanometer heavy anticorrosive material is built in desulphurization denitration inner wall of tower, to effectively prevent acid
Corrosion of the property liquid to inner wall of tower.
The nano combined heavy antisepsis of technological innovation " plastic-metal " protective layer, chloride permeability rate are 3.6 × 10-5, than country
Standard 5 × 10-3Low two orders of magnitude have the ability of very strong barrier acid solution leakage, non-leakage under certain film thickness.
Two kinds of Material claddings of process innovation, simple for process, proportion is only 1.02kg/l, and construction safety is easy, can be shortened big
Measure the duration.It is provided simultaneously with superpower adhesive force and wearability, the long-term of liquid can be born and washed away, heavy metal is free of, is food-grade
Safety and environmental protection material；
Embodiment
Through large-scale weights such as sinopec Guangzhou Branch catalytic cracking and desulfurizing denitration equipment, BP companies of Britain desulphurization denitration TPA equipments
Point engineering project actually uses verification more 2 years, efficiently solve the Anticorrosion Problems under desulphurization denitration harsh environment.
Claims (3)
1. one kind urging cracking unit desulphurization denitration inner wall of tower anticorrosion composite membrane, which is characterized in that FS300 nanofiber desulfurization
II type of priming paint way is to bottom 8~10, and 600 μm of the dry film overall thickness of II type of FS300 nanofiber desulfurization priming paint, FD300 receives
Rice desulfurization current potential adjusts II type of paint way to surface 1,80 μm of dry film overall thickness, the bottom FS300 nanometer desulfuration priming paint II
Type adjusts 680 μm of the dry film overall thickness of II type of paint with surface FD300 nanometer desulfuration current potentials.
2. one kind urging cracking unit desulphurization denitration inner wall of tower anticorrosion composite membrane implementation, which is characterized in that including following step
Suddenly：
Pre-processing：
1）High-lift operation hanging cradle is built as construction tool；
2）Surface sand-blasting process is carried out to inner wall of tower surface substrate, abrasive material uses copper ore, forbids to carry out operation using river sand；
3）Abrasive blasting derusting reaches Sa3 grades, or reaches St3 grades using power tool polishing derusting；
4）Surface requirements of constructing are clean, dry;All macroscopic greases, oil, dirt, lubricant and other pollutants must be complete
Portion removes；
5）Desulphurization denitration inner wall of tower remains clean and tidy, clean;Repeatability must to be carried out to construction surface clear before per pass paint application
It is clean, keep ventilation, inner wall to keep dry state；
Composite membrane is implemented：
1）Reach construction surface requirements in surface cleaning state, smears first of FS300 nanometer desulfurations priming paint (II), thickness of dry film
60 μm, from inner wall of tower top to bottom application and there cannot be holiday defect, abutment joint region carries out pre-coating；
2）After first of coating surface is done something in disregard of obstacles, application second FS300 nanometer desulfurations are carried out from top to bottom using spraying equipment
Priming paint (II), 80 μm of thickness of dry film；
3）After second coating surface is done something in disregard of obstacles, application third road FS300 nanometer desulfurations are carried out from top to bottom using spraying equipment
Priming paint (II), 80 μm of thickness of dry film；
4）After coating surface is done something in disregard of obstacles after third road, the 4th FS300 nanometer desulfurations of application are carried out from top to bottom using spraying equipment
Priming paint (II), 80 μm of thickness of dry film；
5）After the 4th coating surface is done something in disregard of obstacles, the 5th FS300 nanometer desulfurations of application are carried out from top to bottom using spraying equipment
Priming paint (II), 80 μm of thickness of dry film；
6）After the 5th coating surface is done something in disregard of obstacles, the 6th FS300 nanometer desulfurations of application are carried out from top to bottom using spraying equipment
Priming paint (II), 80 μm of thickness of dry film；
7）After the 6th coating surface is done something in disregard of obstacles, the 7th FS300 nanometer desulfurations of application are carried out from top to bottom using spraying equipment
Priming paint (II), 80 μm of thickness of dry film；
8）After the 7th coating surface is done something in disregard of obstacles, the 8th FS300 nanometer desulfurations of application are carried out from top to bottom using spraying equipment
Priming paint (II), 80 μm of thickness of dry film；
9）After the 8th coating surface is done something in disregard of obstacles, the 9th FD300 nanometer desulfurations of application are carried out from top to bottom using spraying equipment
Current potential adjusts II type of paint, 80 μm of thickness of dry film；
10）After the 9th coating surface is done something in disregard of obstacles, carry out routine examination to entire compound layer surface, nine application process dry films are total
680 μm of thickness answers timely processing, entire coat system to must satisfy coating process check criteria, repair coating defect problems
It must dry 7-10 days under the environmental condition divulged information or heated after benefit, routinely be checked again, it is ensured that after qualified
It can put into production use.
3. one kind according to claim 1 urges cracking unit desulphurization denitration inner wall of tower anticorrosion composite membrane, which is characterized in that
The composite membrane can form fine and close intercommunication interpenetrating conductive network structure, and corrosion of metal current potential is made to increase 223mv, corrosion electricity
Flow 173.2 μ A/cm of close decline2, corrosion electric current density substantially reduces, and the condition and difficulty for so that corrosion is occurred improve, while this is multiple
Close adhesive force >=22MP of film and base material steela, chloride permeability rate（mg/cm2.d）≤3.6×10-5, the composite membrane extension at break
Rate, the maximum displacement value being more than under base material limiting temperature situation, elongation at break 62.9%.
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| CN201711235570.9A CN108480157B (en) | 2018-02-08 | 2018-02-08 | Anti-corrosion composite membrane for inner wall of desulfurization and denitrification tower of catalytic cracking unit and implementation method thereof |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN110280461A (en) * | 2019-06-11 | 2019-09-27 | 西安华捷奥海新材料有限公司 | A kind of corrosion-resistant composite membrane of the anti-rock burst device in long-acting corrugated plating tunnel and implementation method |
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| CN105499034A (en) * | 2015-12-30 | 2016-04-20 | 山东瑞嘉通风环保科技有限公司 | Internal corrosion resistant treatment process of desulfurization tower |
| CN106622897A (en) * | 2016-12-23 | 2017-05-10 | 山东国舜建设集团有限公司 | Construction process of anticorrosion ceramic organic coating used for inner wall of desulfurizing tower and inner wall of flue |
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| CN102604509A (en) * | 2012-02-08 | 2012-07-25 | 西安华捷奥海新材料有限公司 | Nanofiber heavy-duty anti-corrosive coating, preparation method and spraying method of nanofiber heavy-duty anti-corrosive coating |
| CN105499034A (en) * | 2015-12-30 | 2016-04-20 | 山东瑞嘉通风环保科技有限公司 | Internal corrosion resistant treatment process of desulfurization tower |
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| CN110280461A (en) * | 2019-06-11 | 2019-09-27 | 西安华捷奥海新材料有限公司 | A kind of corrosion-resistant composite membrane of the anti-rock burst device in long-acting corrugated plating tunnel and implementation method |
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