Working layer castable for natural gas reforming furnace and preparation method of working layer castable

Abstract

The invention discloses a working layer castable for a natural gas reforming furnace and a preparation method of the working layer castable. The invention relates to a working layer castable for a natural gas reforming furnace and a preparation method thereof. The preparation method comprises the following three steps: preparing a solid material, preparing a liquid binding agent, and stirring and mixing the solid material and the liquid binding agent. The solid material is prepared from the following components in percentage by weight: 82 to 88 percent of high-purity aluminum oxide electric frit crushed material, 3.5 to 10 percent of electric melting calcium aluminate frit fine grinding powder and 1 to 8 percent of calcined aluminum oxide micro powder. And feeding, mixing and homogenizing the solid materials weighed in proportion by adopting a V-shaped material self-circulation mixer, and then weighing and subpackaging for later use. And the liquid binding agent component comprises 1 part of deionized water, 1.67-3.75 parts of a strong-alkali weak-acid surfactant, 6.67-15 parts of a high-molecular crosslinking regulator and the like. And uniformly stirring the liquid binder solid material and the liquid binder in a weight ratio of (100: 4)-(100: 6) by using a forced stirrer, and carrying out casting molding operation. The prepared working layer castable for the natural gas reforming furnace has the characteristics of being high in component purity, good in material uniformity and stability and high in CO-H2-CO2-H2O-CH4 composite reducing gas corrosion resistance, and is suitable for preparing composite reducing gas in the natural gas reforming furnace.

Description

Technical Field

[0001] The present invention relates to the technical field of composite materials, and particularly relates to a working layer castable for a natural gas reforming furnace and a preparation method thereof. Background Art

[0002] Under the background of "dual carbon", the large-scale and low-cost production of hydrogen has become increasingly important. Among them, the hydrogen production process from natural gas will exist as the main body in a short period of time. A natural gas reforming furnace is a high-temperature device that uses natural gas as a raw material and uses water vapor, CO2, O2 or air as an oxidant to produce a reducing CO and H2 composite gas under high-temperature conditions. Among them, steam reforming is a relatively common method. The process gas contains components such as CO, H2, CO2, H2O, and CH4. Due to the strong reducibility and permeability of the CO and H2 composite gas, the uniformity and stability of the lining material for the natural gas reforming furnace are crucial for the safety and economy of the operation of the entire furnace body.

[0003] Traditional corundum castable is prepared by mixing corundum aggregate, corundum fine powder, cement binder, dispersant and water reducer as initial raw materials in a forced mixer. Among them, the addition amounts of the dispersant and the water reducer are relatively small, and the total addition amount is about 0.5wt%, making it difficult to disperse evenly. At the same time, local segregation will occur between the fine powder and the cement binder during the mixing process. This will result in the formation of regions with uneven micro-components and pores inside the cast lining body. These structural characteristics will be preferentially corroded under high-temperature CO and H2 composite gas conditions, leading to the destruction of the entire lining body and causing safety problems. Summary of the Invention

[0004] The purpose of the present invention is to propose a working layer castable for a natural gas reforming furnace and a preparation method thereof, aiming at the above-mentioned deficiencies of the prior art. The working layer castable for a natural gas reforming furnace prepared by this method has high chemical purity, good structural uniformity, and strong corrosion resistance to CO-H2-CO2-H2O-CH4 composite reducing gas.

[0005] A working layer castable for a natural gas reforming furnace and its preparation method according to the present invention. The preparation method is divided into three steps: preparation of solid materials, preparation of liquid binders, and stirring and mixing of solid materials and liquid binders. The composition of the solid materials includes 82-88 wt% of crushed materials of high-purity alumina fused blocks, 3.5-10 wt% of finely ground powder of fused calcium aluminate blocks, and 1-8 wt% of calcined alumina micropowder. After weighing according to the ratio, the solid materials are fed and mixed and homogenized by a V-type material self-circulation mixer, and then weighed and sub-packed for standby. The components of the liquid binder include 1 part of deionized water, 1.67-3.75 parts of strong base-weak acid surfactants, 6.67-15 parts of polymer cross-linking regulators, etc. The solid materials and the liquid binder are stirred evenly by a forced mixer according to a weight ratio of 100:4-100:6, and then the casting and molding operation can be carried out.

[0006] Further, the Al2O3 content of the high-purity alumina fused block ≥ 99.2 wt%; the particle size distribution of the crushed materials is:

[0007] The particle size less than 8 mm and greater than or equal to 1 mm accounts for 50-55 wt% of the crushed materials,

[0008] The particle size less than 1 mm and greater than or equal to 0.5 mm accounts for 30-40 wt% of the crushed materials,

[0009] The particle size less than 0.5 mm and greater than or equal to 0.2 mm accounts for 10-15 wt% of the crushed materials.

[0010] Further, the Al2O3 content of the calcined alumina micropowder ≥ 98.5 wt%, and the particle size of the calcined alumina micropowder ≤ 5 μm.

[0011] Further, the CaO of the fused calcium aluminate block ≤ 28 wt%, and the particle size of the finely ground powder ≤ 45 μm.

[0012] Further, the V-type material self-circulation mixer can realize the self-circulation stirring of solid mixtures with different particle sizes.

[0013] Further, the type of the strong base-weak acid surfactant is sodium-based phosphate.

[0014] Further, the types of the polymer cross-linking regulators are amine cross-linking agents, carboxylic acid and acid anhydride cross-linking agents.

[0015] A working layer castable for a natural gas reforming furnace prepared by the above preparation method.

[0016] Due to the adoption of the above technical solution, the present invention has the following positive effects compared with the prior art:

[0017] In the preparation process of the working layer castable for natural gas reforming furnaces, the use of a V-type material self-circulating mixer for the preparation of solid materials can eliminate the problem of segregation of fine powder materials that easily occurs in a forced mixer for solid mixtures of different particle sizes. By using a method of mixing a strong base-weak acid surfactant, a polymer cross-linking regulator, and deionized water to prepare a liquid binder, the uniform distribution of additive components with a small addition amount can be achieved by the action of capillary force. Using a method of pre-compounding a sodium-based phosphate surfactant and a polymer cross-linking regulator to prepare a liquid binder can ensure the stability of workability during the casting process of the working layer castable for natural gas reforming furnaces, thereby ensuring the stability of the internal component structure of the lining after casting and the elimination of irregular pores.

[0018] The working layer castable for natural gas reforming furnaces prepared by the present invention has been tested: the chemical composition has an Al2O3 content of ≥ 96 wt%; the bulk density is 2.9 - 3.3 g / cm 3 ; the cold flexural strength at 110°C × 24 h is greater than 20 Mpa, and the high-temperature flexural strength at 1000°C × 3 h is greater than 15 Mpa; the linear change at high temperature (1000°C × 3 h) is -0.15% to +0.15%.

[0019] Therefore, the working layer castable for natural gas reforming furnaces prepared by the present invention and the working layer castable for natural gas reforming furnaces prepared by its preparation method have high chemical purity, good structural uniformity, and strong corrosion resistance to CO-H2-CO2-H2O-CH4 composite reducing gases. It is suitable for producing H2 in natural gas reforming furnaces. Specific Embodiments

[0020] The following are specific examples of the present invention to further describe the technical solutions of the present invention, but the present invention is not limited to these examples. Specific Embodiments

[0022] The present invention will be further described below in conjunction with specific embodiments, which is not a limitation of its protection scope.

[0023] To avoid repetition, the materials used in this specific embodiment are uniformly described as follows and will not be repeated in the examples:

[0024] The Al2O3 content of the high-purity alumina fused block is ≥ 99.2 wt%; the particle size distribution of the crushed material is:

[0025] The particle size less than 8 mm and greater than or equal to 1 mm accounts for 50 - 55 wt% of the crushed material,

[0026] The particle size less than 1 mm and greater than or equal to 0.5 mm accounts for 30 - 40 wt% of the crushed material,

[0027] The particles with a size less than 0.5 mm and greater than or equal to 0.2 mm account for 10-15 wt% of the crushed material.

[0028] The Al2O3 content of the calcined alumina fine powder is ≥ 98.5 wt%, and the particle size of the calcined alumina fine powder is ≤ 5 μm.

[0029] The calcium aluminate fused block of the electrofused type has CaO ≤ 28 wt%, and the particle size of the finely ground powder is ≤ 45 μm.

[0030] The V-type material self-circulating mixer can achieve self-circulating stirring of solid mixtures with different particle sizes.

[0031] The type of the strong base and weak acid surfactant is sodium-based phosphate.

[0032] The types of the polymer crosslinking regulator are amine crosslinking agents, carboxylic acid and acid anhydride crosslinking agents.

[0033] Example 1

[0034] A working layer castable for a natural gas reforming furnace and a preparation method thereof. The preparation method described in this example is as follows:

[0035] The preparation method is divided into three steps: preparation of solid materials, preparation of liquid binders, and stirring and mixing of solid materials and liquid binders. The composition of the solid materials includes 82-83.5 wt% of crushed materials of high-purity alumina electrofused blocks, 3.5-5 wt% of finely ground powder of calcium aluminate fused blocks of the electrofused type, and 6-8 wt% of calcined alumina fine powder. After weighing in proportion, the solid materials are fed and mixed and homogenized by a V-type material self-circulating mixer, and then weighed, sub-packaged and reserved. The liquid binder components include 1 part of deionized water, 1.67-1.88 parts of strong base and weak acid surfactants, 12-15 parts of polymer crosslinking regulators, etc. The solid materials and the liquid binder are stirred evenly by a forced mixer according to a weight ratio of 100:4 to 100:4.5, and then the casting and molding operation can be carried out.

[0036] The working layer castable for a natural gas reforming furnace prepared in this example is tested: the chemical composition shows that the Al2O3 content is ≥ 96 wt%; the bulk density is 2.9-3.3 g / cm 3 ; the room temperature flexural strength at 110 °C × 24 h is greater than 20 Mpa, and the high temperature flexural strength at 1000 °C × 3 h is greater than 15 Mpa; the linear change at high temperature (1000 °C × 3 h) is -0.15% to +0.15%.

[0037] Example 2

[0038] A working layer castable for a natural gas reforming furnace and a preparation method thereof. The preparation method described in this example is as follows:

[0039] The preparation method is divided into three steps: preparation of solid materials, preparation of liquid binder, and stirring and mixing of solid materials and liquid binder. The composition of the solid materials includes 81-84 wt% of crushed high-purity alumina fused block, 4-6 wt% of finely ground fused calcium aluminate block powder, and 5-7 wt% of calcined alumina micropowder. After weighing the solid materials in proportion, a V-type material self-circulating mixer is used for feeding, mixing, and homogenizing, and then they are weighed, packaged, and reserved. The components of the liquid binder include 1 part of deionized water, 1.7-1.92 parts of strong base-weak acid surfactants, 11-14 parts of polymer cross-linking regulators, etc. The solid materials and the liquid binder are stirred evenly by a forced mixer at a weight ratio of 100:4.2-100:5, and then the casting and molding operation can be carried out.

[0040] The working layer castable for natural gas reforming furnace prepared in this example was tested: the chemical composition of Al2O3 content ≥ 96 wt%; the bulk density is 2.9-3.3 g / cm 3 ; the cold flexural strength at 110°C × 24 h is greater than 20 Mpa, and the high-temperature flexural strength at 1000°C × 3 h is greater than 15 Mpa; the linear change at high temperature (1000°C × 3 h) is -0.15% to +0.15%.

[0041] Example 3

[0042] A working layer castable for natural gas reforming furnace and its preparation method. The preparation method described in this example is as follows:

[0043] The preparation method is divided into three steps: preparation of solid materials, preparation of liquid binder, and stirring and mixing of solid materials and liquid binder. The composition of the solid materials includes 83.5-86 wt% of crushed high-purity alumina fused block, 5.5-8 wt% of finely ground fused calcium aluminate block powder, and 3.5-6 wt% of calcined alumina micropowder. After weighing the solid materials in proportion, a V-type material self-circulating mixer is used for feeding, mixing, and homogenizing, and then they are weighed, packaged, and reserved. The components of the liquid binder include 1 part of deionized water, 1.8-2.75 parts of strong base-weak acid surfactants, 8-13 parts of polymer cross-linking regulators, etc. The solid materials and the liquid binder are stirred evenly by a forced mixer at a weight ratio of 100:4.5-100:5.2, and then the casting and molding operation can be carried out.

[0044] The working layer castable for natural gas reforming furnace prepared in this example was tested: the chemical composition of Al2O3 content ≥ 96 wt%; the bulk density is 2.9-3.3 g / cm 3 ; the cold flexural strength at 110°C × 24 h is greater than 20 Mpa, and the high-temperature flexural strength at 1000°C × 3 h is greater than 15 Mpa; the linear change at high temperature (1000°C × 3 h) is -0.15% to +0.15%.

[0045] Example 4

[0046] A working layer castable for a natural gas reforming furnace and a preparation method thereof. The preparation method described in this embodiment is as follows:

[0047] The preparation method is divided into three steps: preparation of solid materials, preparation of liquid binders, and stirring and mixing of solid materials and liquid binders. The composition of the solid materials includes 84-88 wt% of crushed high-purity alumina fused blocks, 8-10 wt% of finely ground fused calcium aluminate blocks, and 1-3.5 wt% of calcined alumina micropowder. After weighing the solid materials in proportion, they are fed into a V-type material self-circulating mixer for mixing and homogenization, and then weighed and sub-packaged for standby. The components of the liquid binder include 1 part of deionized water, 2.75-3.7 parts of strong base and weak acid surfactants, 2.75-3.75 parts of polymer cross-linking regulators, etc. The solid materials and the liquid binder are stirred evenly by a forced mixer according to a weight ratio of 100:5-100:6, and then the casting and molding operation can be carried out.

[0048] The working layer castable for a natural gas reforming furnace prepared in this embodiment is tested: the chemical composition Al2O3 content ≥ 96 wt%; the bulk density is 2.9-3.3 g / cm 3 ; the room temperature flexural strength at 110°C × 24 h is greater than 20 Mpa, and the high temperature flexural strength at 1000°C × 3 h is greater than 15 Mpa; the linear change at high temperature (1000°C × 3 h) is -0.15% to +0.15%.

[0049] Where not otherwise involved above, it is applicable to the prior art.

[0050] Although some specific embodiments of the present invention have been described in detail by way of examples, those skilled in the art should understand that the above examples are only for illustration and not for limiting the scope of the present invention. Those skilled in the technical field to which the present invention pertains can make various modifications or supplements to the described specific embodiments or use similar methods for substitution, but will not deviate from the direction of the present invention or exceed the scope defined by the appended claims. Those skilled in the art should understand that any modifications, equivalent substitutions, improvements, etc. made to the above embodiments based on the technical essence of the present invention should be included in the protection scope of the present invention.

Claims

1. A working layer castable for a natural gas reforming furnace and a preparation method thereof, characterized in that: The preparation process includes three steps: preparation of solid materials, preparation of liquid binder, and stirring and mixing of solid materials and liquid binder. The composition of the solid materials includes 82-88 wt% of crushed materials of high-purity alumina fused block, 3.5-10 wt% of finely ground powder of fused calcium aluminate block, and 3-8 wt% of calcined alumina micropowder. After weighing in proportion, the solid materials are fed, mixed and homogenized by a V-type material self-circulating mixer, and then weighed, sub-packed and reserved for use. The components of the liquid binder include 1 part of deionized water, 1.67-3.75 parts of surfactant of strong base and weak acid type, 6.67-15 parts of polymer cross-linking regulator, etc. After stirring evenly, it is left standing for standby. Finally, the solid materials and the liquid binder are stirred evenly by a forced mixer according to the weight ratio of 100:4-100:6, and then the casting and molding operation can be carried out.

2. The working layer castable for natural gas reforming furnace and its preparation method according to claim 1, characterized in that, The step-by-step preparation includes: three steps of preparation of solid materials, preparation of liquid binder, and stirring and mixing of solid materials and liquid binder.

3. The working layer castable for natural gas reforming furnace and its preparation method according to claim 1, characterized in that, The Al2O3 content of the high-purity alumina fused block is ≥99.2 wt%; the particle size distribution of the crushed materials is: The particle size less than 8 mm and greater than or equal to 1 mm accounts for 50-55 wt% of the crushed materials, The particle size less than 1 mm and greater than or equal to 0.5 mm accounts for 30-40 wt% of the crushed materials, The particle size less than 0.5 mm and greater than or equal to 0.2 mm accounts for 10-15 wt% of the crushed materials.

4. The working layer castable for natural gas reforming furnace according to claim 1 and its preparation method are characterized in that, The Al2O3 content of the calcined alumina micropowder is ≥98.5 wt%, and the particle size of the calcined alumina micropowder is ≤5 μm.

5. The working layer castable for natural gas reforming furnace according to claim 1 and its preparation method are characterized in that, The CaO of the fused calcium aluminate block is ≤28 wt%, and the particle size of the finely ground powder is ≤45 μm.

6. The working layer castable for natural gas reforming furnace and its preparation method according to claim 1, characterized in that, The V-type material self-circulating mixer can realize self-circulating stirring of solid mixtures with different particle sizes.

7. The working layer castable for natural gas reforming furnace according to claim 1 and its preparation method are characterized in that, The type of the surfactant of strong base and weak acid type is sodium-based phosphate.

8. The working layer castable for natural gas reforming furnace and its preparation method according to claim 1, characterized in that, The types of the polymer cross-linking regulator are amine cross-linking agents, carboxylic acid and acid anhydride cross-linking agents.

9. A working layer casting material for a natural gas reforming furnace prepared by the preparation method according to any one of claims 1-8.