The double-beam active lime kiln has the advantages of low heat consumption, high lime activity, strong fuel adaptability, simple structure and low cost.

It is suitable for the iron and steel industry to use blast furnace gas and coke oven gas, and the chemical industry and calcium carbide industry to use calcium carbide furnace tail gas or co-firing with coal powder to achieve the purpose of improving lime quality and energy saving, and calcining high-quality active lime.

 

 

 

 

 

1. The kiln body is quasi rectangular or circular. The kiln body is equipped with two layers of burner beams, the middle kiln body is equipped with a peripheral burner, and the upper part of the kiln body is equipped with a layer of exhaust gas suction beam. They divide the kiln into five areas, and the calcination process includes material storage zone, pre-heating zone, calcination zone, post-calcination zone and cooling zone.

â—† From the upper part of the suction beam to the kiln top is the material storage belt, which is used to store a proper amount of limestone to ensure that the kiln does not need to be shut down once the charging device on the kiln top needs short-term maintenance, so as not to affect production.

â—† The pre-heating zone is between the suction beam and the upper burner beam, and the limestone is preheated with the kiln gas calcined at high temperature.

â—† There is a calcination zone between the upper burner beam and the lower burner beam. In this zone, limestone is uniformly calcined into high-quality lime. The height of this area can be adjusted according to the quality requirements of lime or the physical properties of limestone.

â—† The area between the lower burner beam and the lower suction beam is a post-calcination zone. The calcined lime enters the high temperature and pressure-free quiet atmosphere in this area for homogenization and finishing, which significantly improves the lime activity.

◆ There is a cooling zone between the lower burner beam and the ash outlet. The cooling air enters the kiln from the bottom and cools the limestone to about 75 ℃ and exits the kiln. The heated secondary air enters the calcination area upward to continue to play a role in supporting combustion.

 

2. The burner beam of two-layer beam combustion device is the core part of the kiln. A number of fuel (gas, liquid and solid) feed pipes are introduced into the beam, and the burner distributes the fuel evenly on the kiln section and evenly mixes with combustion air for combustion. The number of burner beams in each layer is the same as that of special burners. So as to ensure the uniform temperature distribution on the whole kiln section, realize efficient and uniform calcination, so that the lime will not be burnt, reduce the raw overburning rate, and increase the lime activity. This is a major feature of the kiln.

In order to protect the burner beam working at high temperature in the calcination area, medium (water or heat transfer oil) is introduced into the interlayer of the burner beam for circulating cooling. The medium (water or heat transfer oil) is cooled by the cooler to reduce the temperature and continue to circulate for cooling. The primary air is preheated by the exhaust gas and then sent into the kiln by the burner beam. Heat energy is fully utilized to reduce heat consumption. In order to ensure the absolute safety of the burner beam, an alarm is set when the temperature of the medium (water or heat transfer oil) exceeds the temperature, and a standby pump is provided to ensure the continuous circulation of the medium (water or heat transfer oil).

 

3. A layer of exhaust gas suction beam is set at the upper part of the kiln. The quantity depends on the size of the kiln. There are many evenly distributed openings on the lower side of the suction beam. The kiln gas is drawn out by the suction beam through the openings to ensure that the negative pressure of the whole kiln section is evenly distributed.

 

4. The use of two-way pressure system is another important feature of the kiln. The secondary air is blown in by a small blower and enters the cooling zone through a specially shaped distribution beam to evenly cool the lime, so that the positive pressure is maintained below the calcination zone in the kiln, which is easier to accurately control the primary and secondary air volume than the full negative pressure system. The exhaust gas at the upper part of the kiln is pumped out by an adjustable induced draft fan to keep the negative pressure above the calcination area in the kiln and make the heating temperature on the kiln section uniform. The adjustment range of air volume is from 10% to 100%. By adjusting and balancing the amount of combustion air required, the kiln can work under the best operating conditions, so as to ensure good combustion, reduce heat consumption, reduce power consumption and reduce production costs.

 

During the construction process, the anchor parts shall be welded first, and then the refractory ceramic fiber felt and calcium silicate board shall be pasted with high-temperature adhesive. Then lay light thermal insulation bricks, and then compact them with light thermal insulation self-flowing castables, and then lay high-alumina bricks for the working layer.

 

 

1. Before construction, the setting out shall be carried out according to the measured dimensions before demolition. The vertical lines shall be hung at the four corners to ensure the perpendicularity of the furnace wall during masonry. Bricks shall be arranged in advance before masonry, and complex or important parts can be pre-built if necessary.

2. The refractory bricks in the furnace wall shall not use broken bricks less than or equal to 1/2 brick length, and the number of broken bricks in each layer shall not exceed 2. Special cutting tools shall be used when breaking bricks, and the cutting section shall be polished.

3.  Masonry shall be built in staggered joints. Brick joints of adjacent bricks in front of and behind the same brick layer and upper and lower brick layers shall not be overlapped. The distance between upper and lower brick joints shall be less than 50mm. The masonry shall be horizontal and vertical, and the surface shall be smooth and flat to ensure that there is no dislocation.

4. In the brick joints of the masonry, the bonding agent shall be full and the joints shall be tight. The five faces of the brick body shall be full of mud. The thermal insulation brick joint shall be 2~2.5mm, and the high alumina brick joint shall be 1.8mm. The surface shall be pointed, and the brick surface shall be clean after masonry.

5. It is not allowed to cut and chisel bricks on the masonry. During the masonry, use a rubber hammer to align, and do not knock the masonry after the initial setting of the slurry.

6. Arch crown masonry is very important. The arch crown bricks shall be pre-built and assembled on site, and then the arch mold shall be made according to the size of the drawing. The mortar joint shall be less than 1.8mm during masonry. The corresponding arch height mold shall be made before pouring the castable, and then the pouring shall be carried out. The expansion joint of castable shall be reserved during pouring.

7. After the upper suction beam and manhole are poured with high-temperature and wear-resistant castables, they are sealed with insulating cotton to lower the temperature of kiln skin. The anchor shall use 304 stainless steel bars with a diameter of 10-12mm. The insulating material between the pouring layer and the furnace shell shall be poured tightly with castables.

 

 

1. Production capacity: 100t/d-600t/d.

The operating flexibility of the kiln can be adjusted from 70% to 100%. Taking a 300t/d kiln as an example, the production capacity can be adjusted arbitrarily within the range of 210t/d-300t/d, and stable operation can be achieved without affecting the quality and consumption indicators.

2. Limestone particle size

30mm-60mm; 40mm-80mm, particle size range ratio is 1:2.

3. Fuel type

The kiln can use natural gas, fuel oil, pulverized coal, coke oven gas, low calorific value gas (such as pure blast furnace gas), calcium carbide furnace gas, etc. as fuel. In addition to the above, an important feature is that the kiln can use a mixture of the above fuels (gas-gas, gas-liquid, gas-solid, liquid-solid and other mixtures).

4. Lime product

Good quality, high activity (up to 360ml, 4N HCL method for 10 minutes), lime quick-burning rate of 3-6% lime product: good quality, high activity (up to 360ml, 4N HCL method for 10 minutes), lime quick-burning rate of 3-6%.

5. Low heat consumption

the heat energy of the kiln is reasonably utilized. The primary air is preheated by flue gas, and the secondary air is preheated by cooling lime. The fuel is completely burned, and the heat of the fuel is fully utilized, so the heat consumption is low, about 800-900kcal/kg lime.

6. High operation rate

It can operate continuously for 48-50 weeks every year.

7. Calcination method

The latest technology of our company - 3-way pressure system calcination method is adopted to lower the calcination rate of the produced lime, especially the lime activity.

 

http://www.greatwallmachines.com/