CN113501681B - Temperature-resistant anti-corrosion lining coating for riser heat exchanger and construction method - Google Patents

Abstract

The invention relates to a temperature-resistant anti-corrosion lining coating for a riser heat exchanger and a construction method. The lining coating comprises 40.0-50.0% of electric mullite, 32.0-42.0% of silicon carbide powder, 5.0-10.0% of alumina micropowder, 2.0-10.0% of steel fiber and 2.0-10.0% of cement in percentage by mass, wherein the total mass of the electric mullite, the silicon carbide powder, the alumina micropowder, the steel fiber and the cement is 100% of the total mass of the electric mullite, the silicon carbide powder, the alumina micropowder, the steel fiber and the cement, and the mass of the silica sol is 5-10% of the total mass of the electric mullite, the silicon carbide powder, the alumina micropowder and the steel fiber; the construction method comprises the steps of mixing solid raw materials, preparing the paint, fixing the framework and coating the paint, wherein the prepared paint is uniformly coated on the inner wall of the rising pipe, and baking the paint into a formed solid paint layer after natural curing. The lining coating is uniformly coated on the inner wall of the riser heat exchanger and is fixed through the tortoise shell net, so that the coating is effectively prevented from peeling off, the problems of corrosion, coking and smoking of the riser heat exchanger are effectively solved, the damage of the riser heat exchanger is prevented, and the safety and stability of the heat exchange device are improved.

Description

Temperature-resistant and anti-corrosion lining coating for riser heat exchanger and its construction method

technical field

The invention belongs to the technical field of riser pipe coatings, and in particular relates to a temperature-resistant and anti-corrosion lining paint for heat exchangers of riser pipes and a construction method.

Background technique

At present, the domestic coking process is mainly that the coking coal is heated and dry-distilled in the coke oven with isolated air to generate coke, and at the same time produce a large amount of volatilized raw gas. Among them, the temperature of the red coke released from the coke oven carbonization chamber is 950-1050°C, and the temperature of the raw gas of the coke oven is 650-800°C.

Raw coal gas has complex components, high temperature and strong corrosiveness. When the temperature drops, tar will be precipitated, and the inner wall of the riser heat exchanger will be corroded and tarred during use; the inner wall corrosion will seriously affect the riser tube exchange The service life of the heater and potential safety hazards; the problem of tar formation will cause the coking plant to fail to discharge coke normally, and often emit black and yellow smoke, which will affect the normal operation of the coke oven and cause serious environmental pollution.

Chinese invention patent application CN 106543779 A provides a high-temperature-resistant, corrosion-resistant nano-self-cleaning coating, through nano-silica, nano-zirconia, nano-scale ceramic powder, nano-titanium dioxide, nano-silicon nitride, nano-iron oxide, nano-oxidation Composed of magnesium, triphenyl phosphate, absolute ethanol, aminosilane, and water, the composition is complex. When spraying, it has strict requirements on the surface of the riser and is not easy to squeegee; the self-cleaning coating prevents tar adhesion through the low friction coefficient of the surface layer. However, its heat transfer performance is poor, and it cannot fundamentally solve the problem of tar generation. At present, there is an urgent need for a temperature-resistant and anti-corrosion lining coating and a construction method for a riser heat exchanger.

Contents of the invention

The technical problem to be solved by the present invention is: in view of the above-mentioned defects, the present invention provides a heat-resistant anti-corrosion lining coating and a construction method for the riser heat exchanger. The lining coating is a high-temperature resistant plastic silicon carbide coating, which is evenly coated on On the inner wall of the riser heat exchanger and fixed by the tortoise shell net, it can effectively prevent the paint from peeling off, effectively solve the problems of corrosion, coking and smoking of the riser heat exchanger, prevent the riser heat exchanger from being damaged due to high temperature corrosion, and improve heat transfer. Device safety and stability.

The technical scheme adopted by the present invention to solve the technical problem is as follows: the temperature-resistant and anti-corrosion lining coating for the riser heat exchanger includes the following components: fused mullite, silicon carbide powder, alumina micropowder, steel fiber, cement, silicon Sol. The temperature-resistant and anti-corrosion lining coating for the riser tube heat exchanger uses fused mullite as the coating base material, and is equipped with high-temperature-resistant and corrosion-resistant silicon carbide powder. The lining coating has good high-temperature resistance and anti-corrosion; the introduction The auxiliary agent alumina micropowder can improve the fluidity of the coating and reduce the viscosity of the coating. When used, it can form a continuous solid film with a certain strength to ensure the strength of the coating after forming; the introduced steel fiber can increase the lining coating in use. When cement is introduced, the lining coating has good adhesion to the inner wall of the riser, is easy to paste, and has good plasticity; the introduced silica sol is used as a solvent, which is convenient for electric melting mullite, silicon carbide powder, Alumina micropowder, steel fiber, and cement are dispersed in this solvent system, and the component _SiO2 in the silica sol interacts with fused mullite, silicon carbide powder, and alumina micropowder, and there is intermolecular force and good adhesion , not easy to peel off, easy to dry and shape the paint, short construction period when applied, after the paint is formed, it can isolate the corrosion of the inner wall of the riser by high-temperature raw gas and solve the problem of tar generation.

Further, the mass percentages of the fused mullite, silicon carbide powder, alumina micropowder, steel fiber, and cement are:

The total mass percentage of the fused mullite, silicon carbide powder, alumina micropowder, steel fiber, and cement is 100%, and the quality of the silica sol used is the above-mentioned fused mullite, silicon carbide powder, alumina micropowder , steel fiber, and 5%-10% of the total mass of cement.

Further, the mass percentages of the fused mullite, silicon carbide powder, alumina micropowder, steel fiber, and cement are:

The mass of the silica sol used is 5.5%-7.0% of the total mass of the above-mentioned fused mullite, silicon carbide powder, alumina micropowder, steel fiber and cement. With the coating of this quality composition, the lining coating has high strength after molding and is not easy to be damaged, and it interacts with the skeleton of the tortoise shell net to resist deformation and peeling problems caused by high temperature. The lining coating can withstand high temperatures of up to 2000°C. Long service life; the heat-resistant anti-corrosion lining coating for the riser heat exchanger of this component can also effectively improve the heat transfer coefficient of the inner wall of the riser, and prevent the occurrence of tar precipitation caused by a sharp drop in the temperature of the raw gas due to excessive heat transfer. Solved the problems of coking and smoke in the ascending pipe.

Further, the Al ₂ O ₃ -SiO ₂ content in the fused mullite is not less than 98.2%; the SiC content in the silicon carbide powder is not less than 95%; the Al ₂ O ₃ The content is not less than 98.5%; the steel fiber is a stainless steel filament with a diameter of 0.25mm-1.0mm and a length of 1mm-10.0mm; the content of SiO ₂ in the silica sol is 25%-40%. Limit the appropriate percentage of main components in fused mullite, silicon carbide powder, alumina micropowder, and silicon solution to ensure the physical properties of the lining coating for temperature resistance and corrosion resistance; limit the reasonable steel fiber diameter and length, It facilitates the connection strength between the steel fiber and the inner wall of the riser, the tortoise shell net and the paint itself during coating, and avoids the problem of deformation and peeling of the inner lining coating after forming. The steel fiber also has a heat transfer function, which improves to a certain extent The heat transfer coefficient of the inner wall of the riser heat exchanger.

Further, the silicon carbide powder has a particle size of 150 mesh to 300 mesh; the alumina fine powder is α-Al ₂ O ₃ , and the alumina fine powder has a particle diameter of 600 mesh to 1000 mesh. The use of α-Al ₂ O ₃ alumina powder can improve the insulation performance of the coating, good stability, strong heat resistance, good formability, stable crystal phase, and high hardness; at the same time, silicon carbide powder and alumina powder are limited The appropriate particle size and the size of the particle size cooperate with each other to further improve the strength of the coating after molding, and it is not easy to be damaged.

The construction method of the temperature-resistant and anti-corrosion lining paint for the riser heat exchanger includes the following steps:

S1, mixing solid raw materials, according to the mass ratio of the temperature-resistant and anti-corrosion lining coating for the riser heat exchanger, pour the fused mullite, silicon carbide powder, alumina micropowder, steel fiber, and cement into the mixer respectively In the middle, stir evenly to form a solid mixed castable, set aside;

S2, paint preparation, adding the solid mixed castable mixed in S1 into the silica sol according to the percentage, bonding and stirring until uniform;

S3, the skeleton is fixed, and the inner wall of the heat exchanger of the riser is pretreated by sand blasting and rust removal. After the pretreatment is completed, a tortoise shell net is fixed on the inner wall of the heat exchanger of the riser;

S4, paint coating, the paint prepared in the above S2 is evenly coated on the inner wall of the riser, and baked to form a formed solid paint layer after natural curing. The construction method of this kind of lining coating is simple. After the solid raw materials are mixed evenly, they are evenly stirred with the silica sol. They are prepared and used immediately to avoid air-drying when the coating is left for a long time; the tortoise shell net is introduced to exchange heat with the rising pipe when the coating is formed. The connection skeleton between the inner walls of the device can effectively improve the resistance of the molding coating to the deformation and peeling problems caused by high-temperature starved gas; after coating, the coating is naturally cured and then baked to avoid the rapid evaporation of water at the beginning. Forming cracks, the surface of the coating is flat and free of cracks after coating and molding, the strength is high after molding, it is not easy to break, the construction time is short, and the coating can be put into use after baking, and the work efficiency is high.

Further, the coating thickness of the coating in the S4 coating is greater than the thickness of the tortoise shell net. The relationship between the coating thickness of the paint and the thickness of the tortoise shell net is limited to avoid the exposure of the tortoise shell net to direct contact with the raw gas, which will affect the service life of the ascending heat exchanger coated with the lining paint.

Further, the coating thickness of the coating in the S4 coating is 2mm-10mm. According to the size of the riser heat exchanger, the appropriate paint coating thickness can effectively isolate the high-temperature raw gas from corroding the inner wall of the riser. At the same time, the inner lining paint has high strength after forming, and is not easy to be damaged, deformed or peeled off at high temperature. question.

Further, the time for natural health preservation in S4 is 1h-5h, the time for baking in S4 is 0.5h-2h, and the baking temperature is 250°C-400°C. Limiting the appropriate natural curing time can effectively avoid the cracks caused by the sharp reduction of moisture when the paint is baked and formed, and the paint has a long service life after forming.

The beneficial effects of the present invention are:

1. The temperature-resistant and anti-corrosion lining coating for the riser tube heat exchanger can effectively isolate the corrosion of the inner wall of the riser tube by high-temperature raw gas. After forming, it has high strength and is not easy to be damaged. The problem of peeling off, the lining coating can withstand the high temperature of 2000 ℃, and the service life is long; the heat-resistant and anti-corrosion lining coating for the riser heat exchanger of this component can also effectively improve the heat transfer coefficient of the inner wall of the riser, and prevent the heat transfer caused by excessive heat transfer. It will quickly lead to the occurrence of tar precipitation caused by a sharp drop in the temperature of raw gas, which effectively solves the problems of coking and smoke in the rising pipe, prevents damage to the heat exchanger of the rising pipe caused by high temperature corrosion, and improves the safety and stability of the heat exchange device.

2. The construction method of the temperature-resistant and anti-corrosion lining coating for the riser tube heat exchanger is simple. The solid raw materials are mixed evenly and then mixed with the silica sol. The introduction of tortoise shell nets as the connection skeleton between the coating and the inner wall of the riser heat exchanger can effectively improve the resistance of the forming coating to the deformation and peeling caused by high-temperature raw gas when it is used; the coating is baked after natural curing Forming, to avoid forming cracks caused by the rapid evaporation of water at the beginning, the surface of the coating is flat and free of cracks after forming, the strength is high after forming, it is not easy to break, the construction time is short, and the coating can be put into operation after baking. Use, high work efficiency.

Description of drawings

The foregoing and other objects, features and advantages of the present invention will become apparent from the following detailed description in conjunction with the accompanying drawings.

Fig. 1 is the structural representation of riser heat exchanger after construction of the present invention;

Fig. 2 is the cross-sectional schematic view of the riser heat exchanger after construction of the present invention;

Among them: 1. Outer cylinder; 2. Insulation layer; 3. Heat exchange layer; 31. Water inlet; 32. Heat exchange chamber; 33. Water outlet; 34. First distributor; 35. Second distributor; 36. The third distributor; 4. Inner cylinder; 5. Lining coating; 6. Tortoise shell net; 71. Upper connecting flange; 72. Lower connecting flange; 8. Smoke channel.

Detailed ways

In order to make the purpose, technical solution and advantages of the present invention more clear, the present invention will be further described in detail below in conjunction with the accompanying drawings and examples. It should be understood that the specific embodiments described here are only used to explain the present invention, not to limit the present invention.

Example 1

Calculated on the basis of 100kg of solid raw materials, fused mullite, silicon carbide powder, alumina micropowder, steel fiber, and cement, 42.5kg of fused mullite, 42.0kg of silicon carbide powder, 5.6kg of alumina micropowder, 3.5kg of steel fiber, 6.4kg of cement, and 5.2kg of silica sol; the content of Al ₂ O ₃ -SiO ₂ in the fused mullite is not less than 98.2%; the content of SiC in the silicon carbide powder is 97% %, the particle size of silicon carbide powder is 200 mesh; the alumina fine powder is α-Al ₂ O ₃ , the particle size of alumina fine powder is 800 mesh, and the content of α-Al ₂ O ₃ is 99.0%; the steel The diameter of the fiber is 0.5mm, and the length is 3.0mm-5.0mm stainless steel filament; the SiO ₂ content in the silica sol is 30%.

When preparing this kind of lining coating, pour the solid raw materials fused mullite, silicon carbide powder, alumina micropowder, steel fiber, and cement into the mixer, stir evenly, and pour the mixed solid mixture into the silicon solution Disperse evenly and set aside.

Example 2

Calculated on the basis of 100kg of solid raw material fused mullite, silicon carbide powder, alumina micropowder, steel fiber and cement, 48.0kg fused mullite, 32.0kg silicon carbide powder, 7.0kg alumina micropowder, 7.5kg of steel fiber, 5.5kg of cement, and 6.0kg of silica sol; the content of Al ₂ O ₃ -SiO ₂ in the fused mullite is not less than 98.2%; the content of SiC in the silicon carbide powder is 97% %, the particle size of silicon carbide powder is 200 mesh; the alumina fine powder is α-Al ₂ O ₃ , the particle size of alumina fine powder is 800 mesh, and the content of α-Al ₂ O ₃ is 99.0%; the steel The diameter of the fiber is 0.5mm, and the length is 3.0mm-5.0mm stainless steel filament; the SiO ₂ content in the silica sol is 30%.

Example 3

Calculated on the basis of 100kg of solid raw materials, fused mullite, silicon carbide powder, alumina micropowder, steel fiber, and cement, 44.8kg of fused mullite, 36.6kg of silicon carbide powder, 7.5kg of alumina micropowder, 5.7kg of steel fiber, 5.4kg of cement, and 6.8kg of silica sol; the content of Al ₂ O ₃ -SiO ₂ in the fused mullite is not less than 98.2%; the content of SiC in the silicon carbide powder is 97% %, the particle size of silicon carbide powder is 200 mesh; the alumina fine powder is α-Al ₂ O ₃ , the particle size of alumina fine powder is 800 mesh, and the content of α-Al ₂ O ₃ is 99.0%; the steel The diameter of the fiber is 0.5mm, and the length is 3.0mm-5.0mm stainless steel filament; the SiO ₂ content in the silica sol is 30%.

Example 4

Calculated on the basis of 100kg of solid raw material fused mullite, silicon carbide powder, alumina micropowder, steel fiber and cement, 45.0kg fused mullite, 36.8kg silicon carbide powder, 7.4kg alumina micropowder, 5.8kg of steel fiber, 5.0kg of cement, and 6kg of silica sol; wherein the content of Al ₂ O ₃ -SiO ₂ in the fused mullite is not less than 98.2%; the content of SiC in the silicon carbide powder is 97% , the particle size of the silicon carbide powder is 200 mesh; the alumina micropowder is α-Al ₂ O ₃ , the particle size of the alumina micropowder is 800 mesh, and the α-Al ₂ O ₃ content is 99.0%; the steel fiber A stainless steel filament with a diameter of 0.5mm and a length of 3.0mm-5.0mm; the _SiO2 content in the silica sol is 30%.

The preparation method of the lining coating is the same as that described in Example 1.

Example 5

The construction method of the temperature-resistant and anti-corrosion lining paint for the riser heat exchanger includes the following steps:

S1, mixing of solid raw materials, according to the mass ratio of the components of the temperature-resistant and anti-corrosion lining coating for the riser heat exchanger described in Embodiment 1-Embodiment 4, the fused mullite, silicon carbide powder, oxidized Aluminum micropowder, steel fiber, and cement are poured into the mixer respectively, and stirred evenly to form a solid mixed castable, which is set aside;

S2, paint preparation, adding the solid mixed castable mixed in S1 into the silica sol according to the percentage, bonding and stirring until uniform;

S3, the skeleton is fixed, and the inner wall of the heat exchanger of the riser is pretreated by sand blasting and rust removal. After the pretreatment is completed, a tortoise shell net is fixed on the inner wall of the heat exchanger of the riser;

S4, paint coating, the paint prepared in the above S2 is evenly coated on the inner wall of the riser, the thickness of the lining paint layer after coating is greater than the thickness of the tortoise shell net, and the thickness of the tortoise shell net is 1mm as an example, in order to effectively isolate high temperature Corrosion of raw gas on the inner wall of the riser, the coating thickness of the paint is 2mm-10mm, and the coating thickness of the paint used in this embodiment is 5.0mm; Depending on the coating thickness of the paint, the natural curing time can be selected as 2-3 hours, and then baked at a baking temperature of 250°C-400°C for 0.5h-2h. Commonly, the baking temperature is controlled at 300°C The baking time is about 1 hour to form a baked solid paint layer, and the rising heat exchanger can be put into use after the baking is completed.

Referring to Fig. 1 and Fig. 2, adopt the construction method of the high-corrosion-resistant lining paint for the riser heat exchanger described in Example 5 to form a new type of riser heat exchange device after construction on the inner wall of the riser, including the inner cylinder 4. The outer cylinder 1, the inner cylinder 4 is arranged inside the outer cylinder 1, the inner cavity of the inner cylinder 4 forms a flue gas channel 8, and the upper end and the lower end of the inner cylinder 4 and the outer cylinder 1 are respectively provided with upper connecting flanges 71 and the lower connecting flange 72; an insulation layer 2 and a heat exchange layer 3 are arranged between the inner cylinder 4 and the outer cylinder 1, the heat exchange layer 3 is arranged outside the inner cylinder 4, and the insulation layer 2 is arranged on The outer side of the heat exchange layer 3; the inner cylinder 4 is a seamless steel pipe, and the inner cylinder 4 is made of heat-resistant alloy steel; the outer cylinder 1 is made of stainless steel; the insulation layer 2 is an airgel fiber felt ; The inner surface of the inner cylinder 4 is provided with a lining coating 5, and the lining coating 5 is fixed to the inner cylinder 4 through the tortoise shell net 6;

The heat exchange layer 3 includes a water inlet 31, a heat exchange chamber 32 and a water outlet 33. The water inlet 31 communicates with the heat exchange chamber 32 through the outer cylinder 1 and the insulation layer 2. The water inlet 31 is arranged near the lower One side of the connecting flange 72; the water outlet 33 passes through the insulation layer 2 to communicate with the outer cylinder 1 and the heat exchange chamber 32, and the water outlet 33 is arranged on the side close to the upper connecting flange 71; the water inlet 31 is set There is a first distributor 34, the water outlet 33 is provided with a second distributor 35, and several third distributors 36 are arranged in the heat exchange chamber 32; the heat exchange chamber 32 is a coil type or a jacket The layout of the heat exchange chamber 32 is set according to the heat exchange requirements of the riser heat exchange device.

The lining coating is a kind of high temperature resistant plastic silicon carbide coating, which is uniformly coated on the inner wall of the riser heat exchanger and fixed by the tortoise shell net, which can effectively prevent the paint from peeling off and effectively solve the corrosion, coking and smoking of the riser heat exchanger To prevent the damage of the riser heat exchanger due to high temperature corrosion, and improve the safety and stability of the heat exchange device; the new riser heat exchange device formed has good stability, long service life and high safety.

Inspired by the above-mentioned ideal embodiment according to the present invention, through the above-mentioned description content, relevant workers can make various changes and modifications within the scope of not departing from the technical idea of the present invention. The technical scope of the present invention is not limited to the content in the specification, but must be determined according to the scope of the claims.

Claims (3)

1. The temperature-resistant and anti-corrosion lining coating for the riser heat exchanger is characterized in that it is composed of the following components: fused mullite, silicon carbide powder, alumina micropowder, steel fiber, cement, and silica sol; The mass percent of described fused mullite, silicon carbide powder, alumina micropowder, steel fiber, cement is:

The quality of the silica sol used is 5.5%-7.0% of the total mass of the above-mentioned fused mullite, silicon carbide powder, alumina micropowder, steel fiber and cement; The Al ₂ O ₃ -SiO ₂ content in the fused mullite is not less than 98.2%; the SiC content in the silicon carbide powder is not less than 95%; the Al ₂ O ₃ content in the alumina micropowder is not less 98.5%; the steel fiber has a diameter of 0.25mm-1.0mm and a length of 1mm-10.0mm stainless steel filament; in the silica sol, the _SiO2 content is 25%-40%; The silicon carbide powder has a particle size of 150 mesh to 300 mesh; the alumina fine powder is α-Al ₂ O ₃ , and the alumina fine powder has a particle diameter of 600 mesh to 1000 mesh. 2. The construction method of the temperature-resistant and anti-corrosion lining coating for the riser heat exchanger is characterized in that it comprises the following steps: S1, mixing solid raw materials, preparing materials according to the mass ratio of temperature-resistant and anti-corrosion lining coatings for riser heat exchangers according to claim 1, mixing fused mullite, silicon carbide powder, alumina micropowder, steel fiber, cement Pour into the blender respectively, stir evenly to form a solid mixed castable, set aside; S2, paint preparation, adding the solid mixed castable mixed in S1 into the silica sol according to the percentage, and stirring until uniform; S3, the skeleton is fixed, and the inner wall of the heat exchanger of the riser is pretreated by sandblasting and derusting. After the pretreatment is completed, a tortoise shell net is fixed on the inner wall of the heat exchanger of the riser tube, and the coating thickness of the paint in the paint coating is greater than the thickness of the tortoise shell net; S4, paint coating, the paint prepared in the above S2 is evenly coated on the inner wall of the riser, and baked into a formed solid paint layer after natural curing; The time for natural health preservation in S4 is 1h-5h, the time for baking in S4 is 0.5h-2h, and the baking temperature is 250°C-400°C. 3. The construction method of heat-resistant and anti-corrosion lining paint for riser heat exchanger according to claim 2, characterized in that: the coating thickness of the paint in the S4 paint coating is 2mm-10mm.

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