Wet spraying repair technology of lime kiln lining
Lime shaft kiln is a thermal equipment, in the long-term production by high temperature erosion, material erosion, especially the calcination of high temperature zone also subject to chemical reaction corrosion. The lining of lime shaft kiln must have the following properties: good volume stability at high temperature for a long time, good re-burning shrinkage, high mechanical strength, good wear resistance, compact structure, low porosity, good slag resistance (chemical corrosion resistance), good thermal insulation performance. The selection of refractory materials and the quality of lining determine the service life of the lime shaft kiln.
Classification:
Description
1. Technical Background
1. Lime shaft kiln belongs to thermal equipment, which is subject to high temperature erosion and material erosion in long-term production, especially in the high temperature zone of calcination, which is subject to chemical reaction corrosion. The lining of lime shaft kiln must have the following properties: good volume stability at high temperature for a long time, good re-burning shrinkage, high mechanical strength, good wear resistance, compact structure, low porosity, good slag resistance (chemical corrosion resistance), good thermal insulation performance. The selection of refractory materials and the quality of lining determine the service life of the lime shaft kiln.
The temperature of the gas medium in the lime kiln is about 1350 ℃. The spraying process uses a coating made of special materials, which is fully equipped with the performance that lime shaft kiln lining must have. It not only solves the shortcomings of clay brick in alkali resistance and poor wear resistance, but also overcomes the problem of high price of alkaline magnesia refractory brick.
2, the use of amorphous refractory wet spraying repair lime shaft kiln lining of advanced technology, more than ten years of practice has proved to have achieved good results. The lime kiln repaired by spraying has good overall structure, wear resistance, high compressive strength, and the spraying surface is not easy to crack. Compared with the masonry process, the capital can be saved by more than half. For example, the total refractory brick lining of the 250m lime shaft kiln is nearly 500 tons, and the working layer alone is more than 250 tons. The general material used by the spraying process is about 100 tons.
Technical and economic comparison of 2. furnace lining repair methods.
At present, there are two methods to repair the damaged furnace lining: one is to take the traditional overall removal of refractory bricks in the kiln and re-masonry; the other is to use amorphous refractory spraying to repair the furnace lining. The two methods are compared as follows:
(1) repair time: from the shutdown of the kiln overhaul to the repair of the kiln after the opening of the kiln, the fastest masonry also takes about 28 days, spraying process repair only takes 12 to 15 days, the latter saves half of the time than the former.
(2) Repair cost: Taking 250m3 lime shaft kiln as an example, it costs 100-1.2 million yuan to overhaul a kiln by masonry process. The spraying process is used to repair a 250m3 lime shaft kiln, which will not exceed 100 tons of spray paint, and the total spraying cost is 50-600000 yuan.
(3) Comparison of workload and environment: The wet spraying process is used to repair the kiln lining according to the damage degree. Only the potholes and erosion surfaces of about 5-6 meters in the damaged parts of the calcination zone are removed. The refractory bricks of about 10 meters above and below the preheating zone and the cooling zone are basically intact and do not need to be removed. The removed tumor impurities are only about 10 tons, and can be cleaned up in 1-2 days. Due to the use of water and moisture measures in the kiln, there is no dust in the material out of the kiln, and there is no need to pile up materials in a large area. The spray coating in the kiln is driven into the kiln by high-pressure pump, which does not affect the environment of the workshop.
(4) Thermal insulation performance and control: The lining of the shaft kiln repaired by the spraying process, the entire kiln wall is smooth and flat, seamless and seamless as a whole, and the thermal insulation performance is good.
(5) The spraying repair process is simple: kiln wall treatment-anchoring setting-spraying-drying kiln.
Main Performance Indexes of 3. High Alumina Wet Spray Coating
Characteristics of 4. spraying process
The characteristics of the spraying process are good overall structure of the furnace lining, wear resistance, high compressive strength, and the spraying surface is not easy to crack. Its advantages are low cost, short construction period and low heat consumption.
(1) Cost saving: Compared with the spraying process and the masonry process, it can be seen that the cost can be saved by more than half.
(2) Short construction period: lime shaft kiln can be put into production after a week of spraying process, and it only takes about 15 days from kiln shutdown to oven production, which is 3/4 shorter than masonry process.
(3) Low heat consumption: lime shaft kiln is repaired by spraying process, the overall structure of the furnace lining is good after spraying, the spray surface is not easy to crack, the hidden danger of air leakage is removed, the thermal efficiency is high, and the thermal insulation performance is good.
(4) Long service life: Judging from the operation of the three vertical kilns of Maanshan Iron and Steel Co., the service life has reached more than 4 years.
Recommended Products
online message
Hebi Zhongsheng Metallurgical Engineering Co., Ltd.
Address: 227 Hengshan Road, qibin district, Hebi City, Henan Province