Satellite cooler belongs to contranatant gas-solid heat transfer equipment, composed of 6 to 15 cylinder configuration surround by the rotary kiln’s discharge end, whose length is generally 4 ~ 7m, diameter of 0.8 ~ 1.4m, long diameter ratio is 4.5 to 5.5, the structure shown in Figure 7.2.
Cylinder is generally composed of welded 10 ~ 15mm thick rolled steel plate, the hot end of the kiln is connected to the cylinder by the elbow pipe, refractory and heat-resistant steel plate are gabled in the hot end and the elbow pipe, the cold end is equipped with heat cast iron or other material of lifting plate in order to increase heat-transfer surface area, circular kiln and kiln are fused in the whole. With the kiln rotating, transmission is separately installed. Cooling cylinder's feeding end has elbow pipe,the heat-resistant refractory brick and lining plate are inside it. Some plants use the special ceramic liner plate in the elbow part,the service-life can be extended.
Burning clinker in the kiln is moving forward as the firing zone, respectively doing material movement in each cooling cylinder. The gas motion and heat exchange process are the same as the single cylinder cooler.Cool air encounter against clinker flowing the clinker's countercurrent, clinker is cooled, the air is hot, then into the kiln as the secondary air. Satellite cooler has simple structure and reliable operation, covering small area without special care due to the fixed kiln.Because the secondary air flows uniformly from cooled cylinder around the kiln, so the flame shape is great, and beneficial to observe the fire operation without ventilation heat loss, exhaust and dust removal and environmental pollution. However due to the multi-cylinder is integrally connected with kiln,thus increasing the kiln load; cooler's length is shorter, the heat conditions are poor, elbow pipe and liner plate are burned and damage by high temperature clinker, thus maintenance workload is large, consumption materials are more;
After damage, the turning joint is easy to cause air leakage, so the secondary air's temperature is not high, usually 350~550 ℃, the clinker’s cooling effect is bad.After cooling, the clinker's temperature is high, up to 200~350 ℃, thermal efficiency is low, generally only 55 % to 65%.
As for larger yield, low heat consumption kiln , such as Lepol kiln, suspension preheater kiln, Cement Kiln, etc,satellite cooler is not easy to extract tertiary air due to insufficient cooling capacity. Because of the structure,the cylinder can not do too much, otherwise the kiln barrel load is large,limiting the multi barrel cooler cooling capability's increase and the applications of the new drying method on the kiln, generally applicable to producing smaller kiln.
New type satellite cooler
The mid-1960s, Denmark Smith made significant improvements on the old-fashioned multi-cylinder cooler, developing a new multi-barrel cooling machine Una Fox; On the early 1970s, the German company KHD has developed Humboldt cooling machines; Krupp- Khabarovsk Syracuse has developed the single cylinder/multi-cylinder combined cooling machines. The new coolers's improvement points are as the following aspects:
(1) Increasing the length of the cooling machine, old style muti-cylinder's aspect ratio (L/D) is generally 4.5 to 5.5, the new satellite cooler's aspect ratio is added to 8-12.
(2) Improved cutting bend structure, and lined with high temperature, wear-resistant ceramic lining.
(3) High-temperature stage is accounted for more than half of the cylinder, lined with refractory, strengthening insulation, protecting the cylinder, reducing heat loss.
(4)Various forms of lifting equipment, forming an ideal curtain material, enhancing convection heat transfer.
(5)Extending the kiln part, adding a set of rolleron the cylinder of the front portion of the cooling cylinder, in order to reduce the kiln load.
(6)Kiln burner extends to the kiln's internal part, maintaining a longer cooling zone in the kiln, in order to reduce the clinker's temperature in the kiln, prevent adhesive blockage of the satellite cooler.
(7)The water cooling apparatus is set at the outlet of the cooling cylinder.
