Detailed introduction
Introduction
Lime shaft kiln, which also called vertical kiln, due to the vertical position of its kiln shell does not rotate, it is known as vertical kiln or shaft kiln. Vertical kiln is always used to produce the products, such as cement, refractory materials (bauxite and mullite), lime, etc. Thus, the commonly used veritical kiln is also known as cement vertical kiln, lime vertical kiln and so on.
There are two main types of shaft kiln: ordinary shaft kiln and mechanical shaft kiln. ordinary shaft kiln is artificial feeding and artificial unloading, or mechanical feeding and artificial unloading; mechanical shaft kiln is mechanical feeding and mechanical unloading. Mechanical shaft kiln has continuous operation, its production quality and labor productivity are higher than ordinary shaft kiln's. With the market development and technological innovation, ordinary shaft kiln has been replaced by mechanized shaft kiln.
With the development and application of rotary kiln, and generally cement shaft kiln can only choose coal as heat source, so application of cement shaft kiln is less and less. Yuhong lime shaft kiln, with its small investments and yield quick returns, and the continuous improvement of the lime shaft kiln technology, it is still widely used in china and foreign areas, such as Southeast Asia area, Central Asia area, the Middle East area and Africa area, etc.
Lime vertical shaft kiln has many forms, the vertical kiln with continuous operation is mostly adopted. Its heating fuel includes coal, nature gas and coal gas. The solid fuel can be added together with the limestone, it can also be burned into gas outside the kiln and then introduced into it. The former is called mixing shaft kiln, the latter is called gas kiln. Mixing shaft kiln has the advantages of large production capacity, fully mechanized procedure, high concentration of kiln gas, high thermal efficiency, good lime quality and so on, so it is often adopted.
Structure of lime kiln equipment is shown below. The kiln shell is formed of ordinary brick or steel plate, its inner is formed of refractory bricks, the thermal insulation material (e.g., asbestos slag, foam diatomite, etc.) is filled between the two layers to reduce heat loss. Air is blowed into the kiln by blower below.
Working Principle:
After mixed well, blocks of limestone and coke are put into the kiln above. They do top-down movement and go through three areas: preheating zone, calcining and cooling zone. Preheating zone is located in the upper part of kiln, accounting for 1/4 of the total height, and it uses the hot kiln gas from the calcining zone to preheat and dry the limestone fuel and evaporate the moisture. When the temperature exceeds 70 degrees, furnace burden starts to burn. Hot kiln gas conducts nearly half heat to furnace burden, and its temperature drops to 50-100 degrees, discharged from the kiln crown. Calcining zone is located in the middle of the kiln, accounting for 1/2 of the kiln height. To avoid over-sintering, this zone temperature should not exceed 1200 degrees. Cooling zone is located in the bottom of the kiln, about 1/4 of the total kiln height, its main role is to preheat the air in the kiln to cool the hot lime to 30-60 degrees, not only recycle the heat but also protect the kiln gate from burning-out.
The main technological conditions to maintain the normal operation of lime kiln is to maintain the normal and stable temerature distribution inside the kiln.
Features:
1. using energy-saving way of calcination.
2. dust removal system makes flue gas and dust keep clever collocation flue gas emissions meet standards;
3. scientific process the waste heat can be most effectively used.
4. distributing equipment has unique structure and uniform distributing quantity.
5. uniform wind supplying maintains good furnace condition.
6. high automation level.
Technical Parameter
| Capacity | Effectivevolume | EffectiveHeight | Cross SectionDiameter | Limestone Size | Heat Consumption | CaO | Active Degree |
|---|
| （t/d） | (m³) | (m) | (m) | (mm)< | (KJ/kg) | (%) | (ml) |
|---|
| 100 | 98 | 20 | 2.5 | 40-80 | <4600 | >90 | >300 |
| 120 | 141 | 20 | 3 | 40-80 | <4600 | >90 | >300 |
| 150 | 202 | 21 | 3.5 | 40-80 | <4500 | >90 | >300 |
| 200 | 301 | 24 | 4 | 40-80 | <4500 | >90 | >300 |
| 300 | 397 | 25 | 4.5 | 40-80 | <4400 | >90 | >300 |
| 400 | 491 | 25 | 5 | 40-80 | <4200 | >90 | >300 |
| 500 | 735 | 26 | 6 | 40-80 | <4200 | >90 | >300 |
