You know which common types of lime kilns
Date：2019-11-13 16:34 Source：cementepcViews:
With the increase in the application of lime kiln, the major lime kiln manufacturers increased the research on equipment, various kiln specifications and models, in order to meet the needs of industrial processing at the same time, the selection of enterprises brought difficulties, you know which common types of lime kiln
1. Type of lime kiln
1.1 rotary kiln
Rotary kiln has the following advantages: the quality of calcined lime is the best among all kiln types.Can burn more than 5mm gravel raw material, is conducive to the utilization of mine resources;High degree of mechanization, simple control system, easy production operation;Single kiln has the highest productivity.
Its disadvantage is that the heat consumption is higher than the vertical kiln, the equipment weight is large, the occupation is much, the investment is high.
1.2 imported vertical kilns (double-bore vertical kilns and sleeve vertical kilns)
This type of shaft kiln has the following advantages: the quality of calcined lime is good;Waste heat can be fully utilized.High thermal efficiency;Compared with rotary kiln, the area is small;The temperature and dust content of the exhaust gas are lower, and it is easy to take measures to purify the exhaust gas, which is beneficial to reduce environmental pollution.
The disadvantage of double - chamber kiln is the complexity of mechanical equipment, which requires high quality of operating workers.Positive pressure operation of kiln body makes maintenance difficult.The disadvantages of the sleeve kiln are the complex structure of the kiln body, the high requirements on the quality of refractory lining materials and the masonry, and the large amount of daily maintenance.The deficiency of beam kiln is that there are few kilns in China, and the grade of lime products is slightly lower than that of other imported kilns.
1.3 gas-fired vertical kiln
The quality of lime is moderate, the lowest investment in the construction of active lime kiln.Because of using gas as fuel, the quality of lime can meet the requirement of active lime when the condition of raw fuel meets the requirement.
The disadvantages are high temperature, low thermal efficiency and low output of single kiln.
2. Kiln type selection principle
Due to the above different kiln types, different characteristics;Different enterprises, different periods, the choice of kiln when the weight of the characteristics are also different.But most of them follow the following principles:
2.1 comprehensive utilization efficiency of resources
In traditional shaft kilns, the lumpiness of calcined raw materials should be more than 40mm, while in limestone mining, the lumpiness composition of raw ore is generally less than 4Omm, accounting for about 1/3 of the total.Considering the comprehensive utilization factors, the rotary kiln has a great advantage (over 10mm), and the double-bore vertical kiln can roast limestone raw materials over 20mm. Therefore, from the perspective of comprehensive utilization of resources, the rotary kiln and double-bore vertical kiln are beneficial to improve the comprehensive utilization rate of resources.
2.2 consider the factors of energy conservation and emission reduction
The double - bore vertical kiln has a unique design structure and its thermal efficiency can reach over 85%.The lowest heat consumption means the lowest energy consumption and the lowest emission of pollutants.Due to the design defects of domestic gas-fired vertical kilns and the use of low-calorific value fuel, the exhaust gas temperature at the top of the kilns is too high, resulting in the highest energy consumption among all kilns.
2.3 reasonable selection according to production scale
In lime industry, equipment upsizing is the development direction, which is beneficial to production management, improve labor productivity and reduce fuel heat consumption.From the view of technology maturity and application practice, rotary kiln has the most large-scale conditions.The annual output of calcining lime in rotary kiln can reach up to 500,000t.
2.4 product production quality
According to product quality (activity degree), the lime kiln type can be roughly divided into three grades: the first grade, rotary kiln, double-bore vertical kiln and sleeve vertical kiln, with activity degree of about 350ml;The second grade, vercas vertical kiln, domestic gas burning vertical kiln, the activity degree of 320ml or so: the third grade, coke vertical kiln, energy saving vertical kiln, the activity degree of about 280ml.Therefore, the kiln type of active lime production should be selected from the previous two grades.
2.5 consider fuel adaptability
The rotary kiln must use coke oven gas with high calorific value gas or coal powder.The imported vertical kilns, such as double-chamber kiln, sleeve kiln and double-beam kiln, can use mixed gas mainly from converter gas.When the specification of vertical kiln is large, the calorific value of gas should be appropriately adjusted, otherwise the utilization coefficient of lime kiln will be affected.
In addition to technological factors, the determination of the new lime kiln type should also be determined by external factors such as site conditions, capital conditions and fuel conditions.The choice of kiln type and specifications should be as simple as possible.The unification of equipment is beneficial to production management, staff training and reduction of spare parts inventory.Thus the production cost can be reduced.