Energy-conservation and emission-reduction type active lime calcination method and apparatus

Abstract

The invention provides a burning method for preparing an energy-conservation and emission-reduction type active lime. The method comprises the following steps: subjecting the raw material (1) limestone to size grading; respectively and evenly distributing the limestone of different grades into each preheating chamber (8.1) of a novel vertical preheater (8), preheating and partially decomposing the limestone with high temperature exhaust gas and introducing the limestone into a rotary kiln (15); calcining and decomposing the limestone under the action of a temperature field to allow CO2 to be produced and the limestone to become lime; and allowing the lime to enter into a shaft well device (18) for annealing and heat exchange, then introducing the lime into a cooling machine (19) for cooling and carrying out screening to separate blocky lime from powdery lime, thereby obtaining finished products, i.e., blocky lime and powdery lime. The invention further provides an apparatus composed of a size grading device (2), a distributor (5), a distribution warehouse (6), the novel vertical preheater (8), the rotary kiln (15), a kiln hood (17), a combustor (16), the shaft well device (18) and the cooling machine (19) for the method. The method and the apparatus provided by the invention has the characteristics of an expandable range of the size of the raw material limestone, low heat consumption, high production efficiency, a high activity degree of the products, low discharge of SO2 and exhaust gas, low cost, simple and convenient operation and capacity of meeting needs of larger-scale industrial production.

Description

Technical field [0001] The invention involves a high -active limestone industrialized production method and device with high activity, low energy consumption, low sulfur and exhaust emissions.It belongs to the field of industrial lime manufacturing. Specifically, it involves a method and device that involves a method and device that uses natural lime as its raw material, uses industrialized methods to produce high -active lime and reduce its energy consumption, reduce sulfur and exhaust emissions.The present invention can also be widely used in the heating of granular materials such as building materials, chemicals, metallurgy. Background technique [0002] So far, the method of producing lime producing lime has two types: vertical kiln burning and rotating kiln.There are ordinary old -fashioned mechanized vertical kiln and modern vertical kiln.Ordinary old -fashioned mechanized vertical kiln has backward craftsmanship, large labor intensity, old equipment, poor quality, high ene...

AI Technical Summary

Problems solved by technology

The disadvantages are: (1) The rate of raw and dead combustion of lime is relatively high

(2) The distribution of limestone in the preheater is uneven, the heat transfer is uneven, and the thermal efficiency is low

Various forms of vertical preheater material receiving areas are located on the inner side of the cross section of the preheater, and the outer space is based on the inner limestone rolling along the angle of repose and then accumulated. The height difference of the layer is very large, the distribution of limestone particle size is uneven, the resistance encountered when the high-temperature exhaust gas from the kiln tail passes through the material layer is greatly different, the distribution of hot air is uneven, and the limestone is heated unevenly

(3) Low pre-decomposition rate

Various forms of vertical preheater discharge are equipped with multiple pushing devices, but limestone can only be pushed into the rotary kiln in sequence. When one pushing device is pushing, other pushing devices are in a waiting state. The more feeding devices, the longer the waiting time; when the pushing device is in the waiting state, the limestone above it is in a static state. As the exchange progresses, the temperature difference between the material and the hot air flow becomes smaller and smaller, and even tends to " Zero", thus slowing down the heat transfer from the limestone surface to the interior, and also reducing the pre-decomposition rate of the preheater

(4) The vibrating vertical cooler adopts multiple vibrating unloading devices to vibrate unloading at the same time. Affected by the difference in vibration frequency, it is difficult to achieve balanced unloading, and it is prone to "heart-pulling" phenomenon, resulting in partial cooling or even red material. The lime is unloaded; at the same time, under the action of the vibration force, the lump lime is easily broken, which reduces the lump lime rate

In addition, the larger the output of the production line, the larger the diameter of the feeding chamber, which brings many technical difficulties to the corresponding support structure and affects the development of larger industrial production.

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