Description
The calcination process of rotary kiln with an output of 300 tons per hour is a commonly used lime production process, which is suitable for the calcination of limestone, chalk, feldspar and other ores. The furnace type used in this process is rotary kiln, which can efficiently complete the calcining process of lime, and has the advantages of high output, low energy consumption, stable furnace temperature, etc., which is widely used in the lime production industry.
Process
(1) Raw material storage and transportation
The limestone with particle size of 10 ~ 50mm is transported to the factory and stacked in the material yard, and the material yard is operated by loaders. The material with qualified particle size is loaded into the receiving trough set up in the material yard by the loader, the receiving trough is fed quantitatively by the feeder, the stone is fed to the high Angle conveyor, and then sent to the screening building. After the qualified particle size of the limestone is screened, it is weighed by the high Angle conveyor and sent to the top silo of the preheater. The powder under the screen is sent to the storage yard by the 3# conveyor and is regularly transported by the forklift truck.
(2) Calcination of limestone
Limestone calcining is composed of vertical preheater + rotary kiln + vertical cooler, the output is 100~1200t/d, the material from the top of the preheater bin through the feed chute into the preheater body, at the same time, the high temperature flue gas from the rotary kiln will preheat the material to more than 1000℃, so that the limestone partial decomposition, and then pushed into the tail of the rotary kiln by the hydraulic push rod. After high temperature calcination in rotary kiln, it is discharged into the cooler, cooled by the cold air blown into the fan, and cooled to the ambient temperature of +60℃ below the cooler. The air blown in by the cooler enters the rotary kiln as secondary air to participate in combustion.
(3) Finished product transportation
After the finished lime is discharged from the cooler, it is transported to each finished lime warehouse by chain conveyor, bucket elevator and belt conveyor. The discharge valve under the lime storage bin is used to load the lime in the bin into the car and the tank car before being transported out. Set up different size silos according to customer reserve requirements. The finished product silo is a circular silo, with 2 finished silos of 5~50mm and 1 finished silo of <5mm. The quantity of each silo is about 800t.
(4) Flue gas treatment
After heat exchange with limestone in the preheater, the temperature of the high temperature flue gas produced by the combustion of rotary kiln is reduced to below 250℃, and then the cyclone dust collector is used for primary dust collection, the large particles of dust are collected, and then the bag dust collector is discharged into the atmosphere by the high temperature fan after dust removal, and the dust concentration of the discharged gas is less than 30mg/m3. A cold risk control system is installed at the inlet of the dust collector to protect the dust collector.
Advantage
1. Efficient
The calcining process of lime rotary kiln has the characteristics of high efficiency, mainly manifested in the following two aspects:
(1) The use of clockwise rotation, limestone stone calcined at high temperature, can be quickly decomposed and sintered into quick lime, high production efficiency.
(2) The utilization rate of the kiln body is high, and the internal space of the kiln body is fully utilized, which can increase the production output.
2. Strong flexibility
The calcining process of lime rotary kiln has the characteristics of strong flexibility, mainly manifested in the following two aspects:
(1) Strong adaptability, can handle a variety of different types of limestone stone.
(2) The calcining temperature is adjustable, and the calcining temperature and the kiln body rotation speed can be adjusted according to different production requirements to obtain the best production results.
3. low energy consumption
The calcining process of lime rotary kiln has the characteristics of low energy consumption, which is mainly manifested in the following two aspects:
(1) The rotary kiln uses a clockwise rotation mode, using limestone stone to rotate under the action of gravity, without consuming additional energy.
(2) Lime rotary kiln can make full use of waste gas and waste heat, improve heat utilization efficiency and reduce energy consumption through heat exchange.