In industrial applications, the traditional use of brickwork refractory bricks for the insulation of the connecting flue has the disadvantages of difficult construction, serious heat loss, large energy consumption, large heat storage, slow temperature rise and fall, and easy cracking. In order to avoid such problems, this paper proposes a construction technology of zirconium-containing refractory ceramic fiber module. The construction technology of zirconium-containing refractory ceramic fiber module is a construction technology specially applied to the insulation project of the connecting flue of the baking furnace. The construction with this technology has the advantages of energy saving such as light weight, low heat storage and low heat loss. Based on my own practical engineering experience, the author analyzes and elaborates the construction principle and details of the key technology of the modular construction of the connecting flue of the calciner.
Principle and key points of modular construction technology
2.1 Technical principle
The basic principle of this technology is: the inner wall of the connecting flue is paved with lightweight thermal insulation material layer by layer, fixed with special technology, tight joints, and excellent thermal insulation and energy saving effect. After the anchor nails are welded on the inner wall of the steel connecting fire channel, the flexible heat shield nano-panel shall be paved tightly on the inner wall of the connecting fire channel, and then the flexible heat shield nano-panel shall be paved and installed with two layers of aluminum silicate fiber standard blanket, which shall be fixed with a quick card, and then the refractory ceramic fiber module shall be sent and tightened along the plastic pipe in the module with a special wrench and bolt, and finally the high-temperature thermal protective coating shall be sprayed on the heating surface of the module. Under this insulation measure, ceramic fiber materials form a close whole, and it is worth noting that its folding modules can be fixed on the steel plate anchor nails of the furnace wall connected with the flue by using anchors.
2.2 Technical features and scope of application
Compared with the traditional construction method, the application of this technology can speed up the construction progress, greatly shorten the construction period, and ensure the construction period; It can effectively reduce the loss of heat sources, increase the thermal energy by 30% compared with traditional refractory materials, and meet the requirements of green construction in terms of energy conservation and environmental protection. It is applicable to thermal insulation works such as fire resistance and thermal insulation of heavy chemical industry, long distance pipeline network, building fire protection and thermal insulation, ship fire protection and high temperature thermal insulation.
2.3 Key technologies and operation points
The key technologies and difficulties are the installation of zirconium-containing refractory ceramic fiber modules, the installation of compensation strips at joints and the leveling of modules. In particular, in the practical application of the project, the guide pipe should first be aligned with the anchor bolt and vertically tightened, and then use a special wrench to send the nut from the heating surface of the module along the plastic pipe and tighten it. In addition, special attention should be paid to the fact that there must be no false thread hanging. In order to prevent the through joint, the fiber blanket of the same material as the module shall be folded in half at the through joint, and the compression ratio of not less than 40% shall be kept to force it in to ensure the high temperature sealing effect between the modules in the connecting flue.
Technological process and application effect
This technology is applied to the heat preservation operation of the connecting flue of the baking furnace of the carbon system project in a certain area of Shanxi Province. The specific technical operation process includes 7 points: production and installation of the connecting fire channel – marking of the inner wall of the fire channel – welding anchor nail – fiber blanket laying – ceramic fiber module installation ^ compensation strip installation – module leveling and coating.
3.1 Fabrication and installation of connecting flue
Blanking of plates: the blanking must be based on the blanking size. In the actual process, the steel plates can be spliced. Generally, the splicing gap is 3.5 ± 0.5mm, and the left and right symmetrical skip welding is required for butt welding. Before rolling the steel plate repeatedly with the plate rolling machine, ensure that the operation index of the equipment is qualified (meet the relevant requirements). In practice, in order to prevent welding deformation, the internal and external surfaces should be welded symmetrically at the same time, and the form of group butt welding should be adopted. Of course, spot welding of angle steel on its inner side can make the welding joint of the workpiece very flat. Before the hoisting of the connecting flue, the pipe support must be inspected and the vertical and horizontal centerline and elevation of the pipe support must be checked to determine the axis and elevation of the pipe. Before the pipeline is in place, all pipe supports shall be installed in place. The support elevation on the same horizontal pipe section shall be kept at the same elevation. The pipeline can be hoisted in place only after it is checked to be correct.
3.2 Lining of furnace wall, welding anchor nail and laying of fiber blanket
After the installation of the flue, the furnace wall of the connected flue shall be marked with chalk and chalk to ensure that the crossing point of the line is consistent with the welding point position indicated in the drawing. In the actual process, there are certain requirements for the welding of anchor nails. The bolts must be vertically welded on the steel plate of the furnace wall (corresponding to the previously marked position). After the welding is completed, the deviation between the center lines of the two adjacent anchor nails must be less than two nanometers, and they should be fully welded to ensure that there will be no loosening, falling off and other phenomena. In order to make the project effect better, it is necessary to use a small weight hammer to knock and check them one by one after welding, and remove the welding slag. After laying the flexible thermal shield nanoboard on the anchor nail, lay two layers of fiber standard blanket on the flexible thermal shield nanoboard, and compact and fix it with a quick card.
3.3 Installation of ceramic fiber module and compensation strip
The installation of ceramic fiber modules and compensation strips is the key point of the construction process. The installation of modules follows the form of “soldier line” – “row by row plus compensation strips”. In the practical process, the first step is to determine the installation position of objects of different specifications and follow the sequence of installation from one side to the other. In particular, in the practical application process of the project, the guide pipe should first be aligned with the anchor bolt vertically and then use a special wrench to send the nut from the direction of the module heating surface along the plastic pipe and tighten it. In addition, special attention should be paid to the fact that there must be no false thread hanging. After the installation of the first row of modules, fold the 20 mm thick fiber needled blanket in half and add the compensation strip. Of course, it should be noted that the same grade as the heating surface should be selected and the design dimension of the drawing should be followed. After the installation of the first row is completed, the installation of the second row can be started, and the construction can be carried out in this order.
3.4 Module leveling and coating
Cut off the packing belt and pull out the splint after the module is installed, and use the clapping plate to level the surface, pull out the guide tube, protective sheet and binding belt. After the surface treatment, conduct a comprehensive inspection and find that the through gap with a width of more than 5mm should be repaired by inserting the folded fiber blanket into the thin steel plate. Use a small spray machine to spray the 1600 ℃ high temperature thermal protective coating onto the laid and installed ceramic fiber module. The coating shall be evenly sprayed. All parts of the heating surface layer (near the inner side of the connecting flue) must be sprayed in place.
3.5 Other key construction points
In engineering, in order to avoid the through-joint of the module at the interface position, staggered joint shall be used. In particular, it is necessary to set a compensation joint at the junction of the wall top, use the fiber blanket to fold in half (and meet the size of the drawing), maintain a compression ratio of not less than 40% and force it in. The main purpose of this is to avoid the high temperature shrinkage at the junction of the heating surface module, and strive to ensure the sealing effect when the temperature is high. When the compensation strip is installed on the furnace top, the compensation strip between modules shall be fixed firmly with U-shaped nails.
In short, this construction technology uses special process to fix the module, and inserts the same material compensation strip into the module joint to ensure that the joint is tight and the thermal insulation effect is good under high temperature. Compared with traditional construction methods, this technology can effectively reduce the loss of heat sources, can increase the heat energy by nearly one third compared with traditional refractory materials, and does not burn, release heat and toxic and harmful gases, reduce the labor intensity of operators, effectively accelerate the construction progress, and energy conservation and environmental protection meet the requirements of green construction.
To sum up, the construction method of “zirconium-containing ceramic fiber module+high-temperature thermal protective coating” is adopted for the construction of the connecting flue of the baking furnace, and the modular construction technology is innovatively applied, and the dry method is adopted, with good energy conservation and environmental protection effects. It overcomes the disadvantages of traditional technology such as difficult construction, large energy consumption, slow temperature rise and fall, easy cracking, etc., effectively accelerates the construction progress, reduces the construction cost, reduces the maintenance frequency, improves the production efficiency, and conforms to the requirements of green and environmental protection construction. It can be widely used in the thermal insulation installation of the connecting flue of the baking furnace of the industrial carbon system, the thermal insulation of the heavy chemical industry, the thermal insulation of the long-distance pipeline network, the building fire insulation, the high temperature thermal insulation and other thermal insulation projects. It has good social and economic benefits, and has been unanimously praised by the relevant units and departments, and is worthy of promotion and application.