阅读说明：本技术 一种硫磺回收反应炉用刚玉-SiAlON-氮化硅梯度砖及其制备工艺 (corundum-SiAlON-silicon nitride gradient brick for sulfur recovery reaction furnace and preparation process thereof ) 是由 王寿杰 陈松林 崔杰 魏翰 牛瑞华 于 2018-07-20 设计创作，主要内容包括：本发明涉及一种硫磺回收反应炉用刚玉-SiAlON-氮化硅梯度复合耐火砖及其制备工艺。复合耐火砖采用梯度设计,梯度分布依次为：工作层、梯度过渡层一、梯度过渡层二、非工作层,梯度过渡层一为重量比2/3工作层和1/3非工作层的混合配比,梯度过渡层二的为重量比1/3工作层和2/3非工作层混合配比。制备方法包括称取原料、湿碾、成型、干燥和高温烧成,将成型的砖坯在120℃干燥48~72h,在1450~1520℃保温3~4h烧结。所制备的梯度耐火砖性能优良,在各层的结合强度高,砖的整体性能好。(The invention relates to gradient composite refractory bricks of corundum-SiAlON-silicon nitride for a sulfur recovery reaction furnace and a preparation process thereof, wherein the composite refractory bricks adopt a gradient design and are distributed in a gradient manner, and sequentially comprise a working layer, a gradient transition layer , a second gradient transition layer and a non-working layer, wherein the gradient transition layer is a mixed proportion of a 2/3 working layer and a 1/3 non-working layer in weight ratio, and the second gradient transition layer is a mixed proportion of a 1/3 working layer and a 2/3 non-working layer in weight ratio.)

The refractory brick for the sulfur recovery reaction furnace is characterized in that the refractory brick is a trapezoidal brick, and a working layer, a transition layer , a second transition layer and a non-working layer are respectively arranged in the vertical direction from the upper bottom surface to the lower bottom surface, wherein the raw materials of the working layer and the non-working layer are different in proportion, the transition layer is formed by mixing the raw materials of the working layer and the non-working layer according to the weight part of 2: 1, and the raw materials of the working layer and the non-working layer are mixed according to the weight part of 1: 2 to form the second transition layer.

2. The refractory brick as claimed in claim 1, wherein the thickness ratio of the working layer, the transition layer , the second transition layer and the non-working layer arranged in the vertical direction from the upper bottom surface to the lower bottom surface is 2: 1: 1: 2.

3. The refractory brick as claimed in claim 1, wherein: the formula of the working layer comprises, by weight, 8-11% of tabular corundum with the particle size of 4-2 mm, 12-22% of tabular corundum with the particle size of 2-1 mm, 9-13% of mesoporous alumina with the particle size of 1-0.5 mm, 15-20% of mesoporous alumina with the particle size of 0.5-0.088 mm, 5-8% of silicon nitride with the particle size of 0.5-0.088 mm, 16-19% of tabular corundum with the particle size of less than or equal to 0.045mm, 8-15% of SiAlON5 with the particle size of less than or equal to 0.045mm, 8-15% of silicon nitride with the particle size of less than or equal to 0.020mm, 1-2% of Suzhou white mud with the particle size of less than or equal to 0.045.

4. The refractory brick as claimed in claim 1, wherein: the non-working layer comprises, by weight, 9-12% of an alumina hollow sphere with the granularity of 3-2 mm, 20-38% of an alumina hollow sphere with the granularity of 2-1 mm, 9-21% of mesoporous alumina with the granularity of 1-0.5 mm, 15-19% of mesoporous alumina with the granularity of 0.5-0.088 mm, 12-15% of andalusite with the granularity of less than or equal to 0.045mm, 8-13% of Suzhou white mud with the granularity of less than or equal to 0.010mm, 3-6% of magnesium carbonate with the granularity of less than or equal to 0.010mm and 2.5-3% of added alumina sol.

5. The process for preparing the refractory brick as claimed in of claim 1-4, which includes weighing raw materials, wet grinding, shaping, drying and high-temperature sintering, and is characterized in that the raw materials are weighed in proportion, the working layer, the gradient transition layer , the gradient transition layer II and the non-working layer are independently mixed and ground, the working layer material, the transition layer material, the transition layer II material and the non-working layer material are sequentially poured into a mould, and are shaped by mechanical pressing or hydraulic pressing, the brick blank is dried for 48-72 h at 120 ℃, and is sintered for 3-4 h at 1450-1520 ℃.

Technical Field

The invention relates to corundum-SiAlON-silicon nitride gradient composite refractory bricks for a sulfur recovery reaction furnace and a preparation process thereof, belonging to the field of refractory materials.

Background

The petroleum chemical enterprise produces a great deal of H in the crude oil refining process₂S is toxic gas, and has great harm to human bodies and the environment. H is recycled through a sulfur recovery reaction furnace₂The combined sulfur in S and other sulfur-containing gases is converted into elemental sulfur, and a very small amount of residual H in tail gas₂The sulfur recovery reaction furnace has the disadvantages of severe working condition environment, high temperature, temperature fluctuation, pressure, corrosion, explosion and other dangerous factors and complicated smoke components, so the requirement on the refractory lining of the reaction furnace is high, and the refractory material with high strength, good corrosion resistance and good thermal shock resistance needs to be selected^-1The compressive strength is more than or equal to 100MPa, and the heat conductivity coefficient is less than or equal to 1.5 W.m^-1·K^-1Or a chromium corundum brick having a bulk density of about 3.0g cm^-1The compressive strength is more than or equal to 80MPa, and the heat conductivity coefficient is less than or equal to 1.8 W.m^-1·K^-1About 150mm thick; the second layer is a light brick which is a light heat-insulating mullite brick with the volume density of 1.1-1.3 g-cm^-1The compressive strength is more than or equal to 8MPa, and the heat conductivity coefficient is less than or equal to 0.45 W.m^-1·K^-1The thickness is about 100 to 150 mm; the third layer is made of a heat-insulating pouring material which is a high-aluminum light pouring material with the volume density of 0.95-1.1 g-cm^-1The compressive strength is more than or equal to 6MPa, and the heat conductivity coefficient is less than or equal to 0.25 W.m^-1·K^-1The thickness is about 100mm, the refractory lining material of the sulfur recovery device is shown in the schematic diagrams of fig. 1 and 2, the three-layer refractory material design has the advantages that the th layer of heavy refractory brick has high strength, good abrasion resistance and erosion resistance, and can resist severe working environment, the second layer of light heat-insulating brick has low heat conductivity, small heat capacity and good heat-insulating effect, and the third layer of light castable has low heat conductivity, good heat-insulating effect and strong adaptability to the shapeAs shown in fig. 3.

In order to eliminate hidden danger of collapse of lining bricks caused by brick dropping due to deformation, the refractory bricks adopt the arc-shaped bricks with large volume (as shown in figure 4), and the gravity and the load of the heavy bricks can be resisted through the extrusion stress and the friction force of the large-angle slope surfaces of the arc-shaped bricks with large volume (as shown in figure 4), so that hidden danger of accidents of brick dropping and collapse is eliminated. However, the arc bricks with large volume must be customized according to the diameter of each reaction furnace, and the slope surfaces of the arc bricks with different diameters are different, so that the different diameters must adopt the dies adapted to the diameters, which causes great waste of the dies and high cost. When there is an order, the mold must be opened first for reproduction, which causes a serious project period for delivery, and when there is no order, the tunnel kiln for sintering the product idles, which causes a great waste of fuel.

In addition, the small-size trapezoidal bricks can adapt to the diameters of different kilns, can be used as samples of standard bricks, can produce stock even when no order is available, and cannot waste fuel due to idle running of a tunnel kiln, but because the current sulfur recovery reaction furnace adopts a three-layer design, the second layer and the third layer of the lining of the reaction furnace are made of light refractory materials, deformation cannot be avoided, the extrusion stress and the friction force of the small-angle gradient surface of the small-size trapezoidal bricks are not enough to resist the gravity collapse and the load of heavy bricks (the stress analysis is shown in figure 5), and brick falling and kiln hidden trouble accidents inevitably exist.

The precondition for eliminating the brick dropping of the small-sized trapezoid brick is only , namely the second layer and the third layer must not deform, the strength of the load must be large enough, and the light refractory material cannot meet the requirement of high strength after long-term hot operation, therefore, the solution only abandons the commonly used idea of three-layer design at present, namely, the design of layers of heavy bricks, the second layer of light bricks and the third layer of light castable is not adopted, but an integral design method is adopted.

Disclosure of Invention

The invention relates to corundum-SiAlON-silicon nitride gradient composite refractory bricks for a sulfur recovery reaction furnace, which are trapezoidal bricks, the longitudinal section of each refractory brick is isosceles trapezoid, the height of each refractory brick is 300-400 mm, the upper bottom surface and the lower bottom surface of each refractory brick are both rectangular or square, the side length of each of the upper bottom surface and the lower bottom surface of each refractory brick is 80-100mm, a working layer, a transition layer , a second transition layer and a non-working layer are respectively arranged in the vertical direction from the upper bottom surface to the lower bottom surface of each refractory brick, the raw materials of the working layer and the non-working layer are different in proportion, the transition layer is formed by mixing the raw materials of the working layer and the non-working layer according to the weight ratio of 2: 1, the transition layer , the second transition layer and the non-working layer which are arranged in the vertical direction from the upper bottom surface to the lower bottom surface of each transition layer is 2: 1: 1: 1: 2.

The raw materials used by the refractory brick comprise: (1) plate-shaped corundum with the granularity of 4-2 mm and 2-1 mm, mesoporous alumina with the granularity of 1-0.5 mm and 0.5-0.088 mm, and silicon nitride with the granularity of 0.5-0.088 mm are used as frameworks; (2) the alumina hollow spheres with the granularity of 3-2 mm and 2-1 mm; (3) plate-shaped corundum powder with the granularity less than or equal to 0.045mm and SiAlON powder with the granularity less than or equal to 0.045mm are taken as matrixes; (4) silicon nitride powder with the granularity less than or equal to 0.020 mm; (5) suzhou white clay with the particle size less than or equal to 0.010 mm; (6) magnesium carbonate powder with the granularity less than or equal to 0.010 mm; (7) and (3) an aluminum sol binder.

The formula of the raw materials of the working layer of the refractory brick comprises the following components in percentage by mass:

(1) 8-11% of plate-shaped corundum with the granularity of 4-2 mm;

(2) 12-22% of plate-shaped corundum with the granularity of 2-1 mm;

(3) 9-13% of mesoporous alumina with the granularity of 1-0.5 mm;

(4) 15-20% of mesoporous alumina with the particle size of 0.5-0.088 mm;

(5) 5-8% of silicon nitride with the granularity of 0.5-0.088 mm;

(6) 16-19% of plate-shaped corundum with the granularity less than or equal to 0.045 mm;

(7) 5-10% of SiAlON with the granularity less than or equal to 0.045 mm;

(8) silicon nitride powder with the particle size of less than or equal to 0.020mm and 8-15 percent;

(9) 1-2% of Suzhou white mud with the granularity less than or equal to 0.010 mm;

(10) and 2.5-3% of alumina sol is added.

The non-working layer of the refractory brick comprises the following raw materials in percentage by mass:

(1) 9-12% of alumina hollow spheres with the granularity of 3-2 mm;

(2) 20-38% of alumina hollow spheres with the granularity of 2-1 mm;

(3) 9-21% of mesoporous alumina with the granularity of 1-0.5 mm;

(4) 15-19% of mesoporous alumina with the particle size of 0.5-0.088 mm;

(5) 12-15% of andalusite with the granularity less than or equal to 0.045 mm;

(6) 8-13% of Suzhou white mud with the granularity less than or equal to 0.010 mm;

(7) 3-6% of magnesium carbonate with the granularity less than or equal to 0.010 mm;

(8) plus alumina sol and 2.5-3%.

The preparation process of the refractory brick comprises the following steps:

(1) and (3) batching and mixing, namely weighing the required raw materials in proportion, and respectively batching and separately mixing and grinding according to the proportion of the working layer, the gradient transition layer , the gradient transition layer II and the non-working layer.

The working layer is prepared by mixing 98 plate-shaped corundum with the particle size of less than or equal to 0.045mm, SiAlON powder with the particle size of less than or equal to 0.045mm, andalusite with the particle size of less than or equal to 0.45mm, silicon nitride powder with the particle size of less than or equal to 0.020mm and Suzhou white mud with the particle size of less than or equal to 0.010mm for 20 minutes in advance, and marking the mixture as A powder for later use, mixing and grinding the 98 plate-shaped corundum with the particle size of 4-2 mm, 2-1 mm, mesoporous alumina with the particle size of 1-0.5 mm, 0.5-0.088 mm and silicon nitride powder with the particle size of 0.5-0.088 mm for 15-20 minutes in a strong manner, adding aluminum sol as a binding agent.

And in the non-working layer, andalusite with the granularity of less than or equal to 0.45mm, Suzhou white mud with the granularity of less than or equal to 0.010mm and magnesium carbonate with the granularity of less than or equal to 0.010mm are mixed strongly for 20 minutes and marked as B powder for later use, mesoporous alumina with the granularity of 1-0.5 mm and 2-1 mm, mesoporous alumina with the granularity of 0.5-0.088 mm are mixed and ground strongly for 15-20 minutes, alumina sol is added as a binding agent, the premixed B powder is added, and is subjected to wet grinding for 30 minutes.

And (3) a gradient transition layer , mixing the material A by 2 weight parts and the material B by 1 weight part, and performing the same processes of pre-mixing and mixing the fine powder and grinding the material A and the material B.

A second gradient transition layer; mixing 1 weight of material A and 2 weight of material B, and performing the same processes of fine powder premixing and wet grinding as those of the material A and the material B.

(2) And (3) forming, namely dividing the die into four areas by using a paperboard, pouring the material A, the material of the transition layer, the material II of the transition layer and the material B into the four areas in sequence according to the cloth sequence of the working layer, the gradient transition layer , the gradient transition layer II and the non-working layer, spreading and flattening, then drawing out the paperboard, and performing mechanical pressing or hydraulic forming.

(3) And (5) drying. And drying the green brick at 120 ℃ for 48-72 h.

(4) And (5) sintering. And (3) preserving the temperature for 3-4 h and sintering at 1450-1520 ℃.

The performance of the firebrick working layer of the invention is as follows: the bulk density is 2.7 to 2.9 g/cm^-1Compressive strength of more than or equal to 80MPa, and heat conductivity coefficient of less than or equal to 1.3 W.m at 1100 DEG C^-1·K^-1(ii) a The properties of the non-working layer were: a bulk density of 1.15 to 1.25 g/cm^-1Compressive strength of not less than 20MPa, and thermal conductivity of not more than 0.6 W.m at 500 DEG C^-1·K^-1。

The refractory brick adopts a gradient transition formula, the bonding strength of the working layer, the transition layer , the transition layer II and the non-working layer is high, the problem of interface falling does not exist between the layers, the overall performance of the brick is good, and the technical effect is outstanding.

(1) The corundum-SiAlON-silicon nitride gradient brick has the advantages that the working layer of the corundum-SiAlON-silicon nitride gradient brick is high in mechanical strength, good in wear resistance, high in refractoriness under load, good in anti-corrosion performance and good in thermal shock resistance, can resist severe working conditions such as high temperature, temperature fluctuation, pressure, corrosion and the like in a sulfur recovery reaction furnace, the non-working layer of the corundum-SiAlON-silicon nitride gradient brick is high in refractoriness under load and low in heat conductivity coefficient, the heat preservation function is achieved, and the corundum-SiAlON-silicon nitride gradient brick has enough support strength.

(2) The working layer and the non-working layer are gradually transited from gradient, the interface bonding strength is good, and the integrity of the brick is good.

(3) Compared with the prior heavy material zirconium corundum mullite brick or chromium corundum mullite brick of the working layer, the brick is lower in cost because of no zirconium and more environment-friendly because of no chromium.

(4) The small-size trapezoidal brick has good universality, can adapt to reaction furnaces with different diameters, can be used as stock for standard brick production, and solves the problems that when an arc brick has an order, a die needs to be independently opened, the cost is increased, the delivery period is delayed, and when no order exists, a tunnel kiln idles, and the fuel is wasted.

Drawings

FIG. 1 is a schematic sectional (cylindrical) view of a sulfur recovery reactor, in which 1 is a heavy brick; 2 is a light heat-insulating brick; 3 is a light castable.

FIG. 2 is a schematic side sectional view (circular ring shape) of a sulfur recovery reactor, wherein 1 is a heavy brick; 2 is a light heat-insulating brick; 3 is a light castable.

FIG. 3 is a schematic sectional side view (oval ring shape) of the sulfur recovery reactor after deformation, wherein 1 is a heavy brick; 2 is a light heat-insulating brick; 3 is a light castable.

FIG. 4 is a schematic view of a large arc-shaped brick and its stress analysis

FIG. 5 is a schematic view of a trapezoidal tile and its force analysis

FIG. 6 is a schematic view of a gradient transition formulation of a gradient brick

Example 1

gradient composite corundum-SiAlON-silicon nitride refractory bricks for sulfur recovery reactor, which are trapezoidal in longitudinal section and 400mm in height, and have rectangular or square upper and lower bottom surfacesThe refractory brick comprises a refractory layer with the side length of 82mm and the bottom side of 95mm, four refractory layers which are formed by different raw materials in proportion along the vertical direction from the upper bottom surface to the lower bottom surface, wherein the refractory working layer comprises, by mass, 4-2 mm of plate-shaped corundum and 8% of plate-shaped corundum and 22% of 2-1 mm of mesoporous alumina, 9% of 1-0.5 mm of mesoporous alumina, 15% of 0.5-0.088 mm of mesoporous alumina, 8% of 0.5-0.088 mm of silicon nitride, 16% of 0.045mm of plate-shaped corundum and 16% of SiAlON, 5% of 0.045mm of mesoporous alumina, 15% of silicon nitride, 15% of 0.010mm of mesoporous alumina, 2% of Suzhou white clay and 3% of non-working layer, A3% of aluminum oxide hollow ball with the granularity of 3mm and 9% of aluminum oxide, 38% of the granularity of 2mm of alumina, a bonding agent of the 1.010 mm of the granularity of the 1.010 mm of the non-0.010 mm of the working layer, a working layer is prepared by adding, a non-sintered alumina hollow ball and a non-2 mm of a working layer prepared by mass, a non-sintered alumina according to a working layer prepared by weight ratio of a wet alumina, a working layer of a working slurry, a working slurry of a working layer of a working slurry of a working slurry of the slurry of 2mm of the slurryMixing 1 weight of A1 material with 2 weight of B1 material, fine powder premixing and wet grinding, the same process as the A1 material and the B1 material, dividing the four regions by using a paperboard in a die, pouring the A1 material, the transition layer material, the transition layer two material and the B1 material into the four regions in sequence according to the cloth sequence of a working layer, the gradient transition layer material, the gradient transition layer two material and a non-working layer, spreading and flattening, then extracting the paperboard, carrying out mechanical pressing or hydraulic forming, drying the brick blank at 120 ℃ for 48h, carrying out heat preservation at 1450 ℃ for 4h, and sintering to obtain the working layer of the refractory brick, wherein the performance parameters of the working layer of the refractory brick are that the volume density is 2.89 g-cm^-1A compressive strength at room temperature of 92MPa and a thermal conductivity at 1100 ℃ of 1.29 W.m.K^-1(ii) a A non-working layer: bulk density 1.17g cm^-1And a heat conduction system of 0.55 W.mK at 500 ℃ and a room temperature compressive strength of 22MPa^-1。