How to Choose Refractory Materials for Gasifiers?

The refractory material of the gasifier can be divided into three parts: the cone bottom, the cylinder body, and the vault. There is a certain expansion space between the vault and the furnace shell so that the lining refractory bricks expand upward when the gasifier is running. It can be divided into several layers from the inside to the outside. Taking the cylindrical refractory material as an example, it is divided into four layers: fireproof refractory material layer, backing layer, heat insulation layer, and compressible layer (the vault is the same as the cone bottom), the front An expansion gap of 3~5mm is reserved between the three layers. Expansion in the convenient radial direction is unrestricted.

1. Refractory bricks facing the fire
The working environment of refractory bricks is very poor, and design units and users are very cautious about their structural design and material selection. A fireproof surface refractory layer: also known as hot surface brick, is a high-temperature-resistant, corrosion-resistant consumable layer. Typically, high chromium materials are required, which require high-temperature chemical stability, high creep strength, and thermal shock resistance. The thickness from the cylinder to the fire surface of the CWS gasifier is about 230mm. Use 90 chrome aluminum zirconium bricks (high chrome bricks). The raw material for chrome-aluminum-zirconium bricks is Cr203 fusion composite material, the content of Cr2O3 is more than 99% (bulk density is more than 5.1g/cm3), and superfine powder is added. After mixing and shaping, it is fired in a high-temperature shuttle kiln. This product has the advantages of high bulk density (greater than 4.25g/cm3), low porosity (less than 16%), high-temperature resistance (greater than 120Mpa), low content of impurities such as iron oxide and silicon oxide, and good heat. Stable energy, temperature creep resistance, etc. all meet the requirements of refractory materials for the gasifier to the fire surface, so 90 chrome aluminum zirconium brick is an ideal product for the gasifier to the fire surface refractory.

2. Backing layer refractory brick
Its main function is heat insulation, but when the refractory brick disappears, it can be used for a short time as a lining. The backing bricks are mostly corundum bricks. The thickness of the cylinder refractory brick is about 200mm. Chromium corundum bricks are made of white corundum sand as aggregate and Cr2O3 as aggregate, which is mixed, formed, and sintered at high temperatures. Refractory bricks are mainly used for the fire surface of the slag mouth of the slag gasifier, the carbon black reactor, and the backing brick of the coal-water slurry gasifier.

3. Insulation layer
The insulating layer needs to be good thermal insulation to keep the metal case within a reasonable temperature range while minimizing heat loss. Alumina hollow ball bricks are generally used. The cylinder fire brick is about 110mm thick. Aluminum 2o3 hollow ball insulating firebrick/casting material is mainly used for the bottom layer of slag hydrocarbon furnace, carbon black reactor, and coal slurry furnace insulation layer.

4. Compressible layer
It can be compressed or recovered within a certain temperature range, thereby reducing the influence of radial thermal expansion stress on the shell. The thickness is about 15~20mm. Commonly used FBX1900 cement is a dry mixture of mineral fibers and no binder, which contains an effective rust inhibitor, but has no corrosive effect. It can be applied with a trowel or spray gun during construction.

In order to strengthen the integrity of the furnace lining, it is required to use a combination of circumferential bricks and longitudinal bricks to prevent the flow of high-temperature gas between the refractory bricks and ensure the pressure shell of the refractory bricks and the backing refractory bricks. In order to improve the integrity of the furnace lining, it is required that the circumference of Both bricks and vertical bricks should be firmly combined with bricks.

How to choose refractory materials for coal gasifiers? I believe you can get a general idea of chrome-aluminum-zirconium bricks (high chrome bricks) for gasifiers, backing layers of corundum or chrome corundum refractory products, and hollow sphere insulating refractory bricks for insulating layers. If you have any other questions, please contact us. Xinhongji Refractory will provide you with a full range of refractory solutions.