Tangshan Tangbao Refractories Co., Ltd.
Address：Beijiadian Third Street, Guye District, Tangshan
I. Corrosion Detection of Lining Refractories
From the structural point of view, the inspection of riser lining can be carried out by contact method, including the use of contact thermometers. The descending tube is located at high altitude, and completely suspended, the length of which can reach 50 to 90 meters. The general means can not detect the corrosion of its lining.
Therefore, the corrosion detection technology of downcomer liner becomes the key to the formulation of maintenance technical scheme. With the development of far-infrared imaging technology, infrared imaging of the whole shell of riser or descender tube is taken by using far-infrared thermal imager, and then the temperature of the inner lining is analyzed by comparing the infrared photographs, and the erosion of the inner lining is indirectly inferred, so as to provide a basis for determining the maintenance location and scheme. In blast furnace, the lining refractories of riser and descender pipes are designed with brick lining and refractory spraying coating. Therefore, special attention should be paid to distinguishing the imaging results of different lining structures when analyzing thermal imaging photographs. According to the statistical results of inspection and repair, the vulnerable parts of the downcomer liner are generally within one third of the lower half ring; the vulnerable parts of the riser liner are at the corner; and the vulnerable parts of the gas seal are around the outlet. Repair technology of lining refractories (1) Repair of lining. As the riser is located above the blast furnace, a platform can be set up to reach the repaired part. Therefore, when repairing, the usual way is to set up repair manholes (or use the original repair manholes) on the pipe body, and repair the lining by spraying from outside to inside. In order to improve the effect of spraying, metal anchors are also installed on the inner surface of the shell. (2) Repair of inner lining of gas seal. Due to temperature fluctuation, impact of burden and scouring effect of high temperature raw gas, the refractory lining of top gas cover of blast furnace can not be synchronized with the life of first generation blast furnace, especially bell-less blast furnace, so intermediate maintenance is needed. Such repairs are usually carried out during blast stoppage. Usually, the refractory material of gas cover lining is sprayed coating with refractory spraying paint. Therefore, maintenance is basically carried out by spraying refractory paint. If the metal anchor in the lining refractory falls off, the metal anchor must be welded and repaired first. (3) Maintenance of downcomer liner. Compared with the maintenance of gas seal and riser liner, the maintenance of downcomer liner is more difficult. In addition to the high position of the structure and the poor construction conditions, there are also downcomers which are generally inclined tubes. In order to complete the repair in the process of wind break, special equipment needs to be designed to improve work efficiency. Such as: special car for manned maintenance, in-pipe movable construction platform and so on. 3. Gas plugging and discharging technology in pipeline. For maintenance of riser and descender pipelines, operators need to enter. In order to ensure safe construction, gas in pipeline must be controlled below 50mg/L. Therefore, how to effectively plug the blast furnace gas source and remove the gas in the pipe becomes the key to the implementation of this technology. Fourth, the application of refractory materials for lining use of refractory brick riser and descendent pipe, repair materials are generally the original design of refractory bricks. For the riser and descender pipes lined with amorphous refractories, refractory spraying coatings are often used when repairing. In view of the actual use conditions, besides the general requirements, the selection of the lining refractories for repair should also pay attention to high strength, wear resistance, CO corrosion resistance and low iron content, so as to withstand the wear and chemical erosion of long-term high-dust and high-speed waste gas.