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    Product Details: Advantages of an Annular Shaft Kiln are lower thermal loss, higher activity of lime, simpler structure and greater fuel adaptability compared with a traditional lime kiln. Lumpy materials such as limestone are going to be calcined and sintered in the annular space with uniformity of air flow distribution There are no cooling units in the kiln, fault rate therefore could be fairly Iow and easy to maintain. The Annular Shaft Kilns are widely applied in iron industry to manufacture high quality lime with coke-oven gas or in chemical industry with calcium carbide furnace gas as its fuel.Technica Fetures:1. Production Capacity: 150t/d, 300t/d, 500t/d, 600t/d four diferent standards of annularshaft kilns can be designed and manufactured by XinHua. Production capacity can beregulated within a certain limits without compromising quality and consumption rates.2. Grain Size: 20-100mm, scale factor 1:33. Fuel type: natural gas, coke oven gas, calcium carbide furnace gas, oil.4. Lime: with up to 1.5% C02 remains(24 hours average value), activity is greater than 360ml(4N, HCL method 10 mins).5. Thermal loss: with the maximum limits use of thermal energy, abstracted heat air from cooling lime and inner shaft and partially exhaust gas generated from combustion aretransferred into calcining zone by an ejector. Under normal situations, the thermal loss can becontrolled within 930kcal/kg.6. OperabBty: 48 weeks consecutively.7. Methods of calcining: a combined method of countercurrent and cocurrent calcining can prevent lime from overburning, ensure that the lime is fully decomposed and dramaticallyimprove the activity of lime.Annular Shaft Kilns  Structural features and process instruction:1. An annular shaft kiln has a circumferential wall surrounding a shaft insert spaced between a inner wall, where lumpy materials such as limestone are processed in the annular space. The body of kiln is consist of a preheating zone a countercurrent calcining zone acocurrent calcining zone and a cooling zone.a) The preheating zone is from Iow air inlets of an upper range of inner cylinder to wastegas outlets of an upper range of the kiln. There are 70% waste gas introducing to the preheating zone to preheat the material after calnining and sintering.b) One of outsranding features of annular shaft kiln is that operation of countercurrent calcining is synchronized with cocurrent calcining process. Two range of burner units form the kiln into one calcining zone with two countercurrent operations and the second calcining zone with one cocurrent operation. the two countercurrent calcining zones are located in an area from upper part of burning region to top of Iow inner cylinder and a space between upper and nether burning regions respectively The cocurrent calcining zone is positioned from the nether burning region to bottom of Iow inner cylinder.c) Incomplete combustion gas is generated in the upper burning region by around 50% insufficient air supply. However, perfect combustion can take place when incomplete combustion gas is induced into a upper layer of material by a draught fan and encounters an airflow which contains excess air from lower regions. The operation above is processed in the areas named upper calcining zone where the direction of airflow is countercurrent to the material flow direction. Under thecountercurrent calcination. limestone is in an initial decomposition stagerequiring to absorb a large quantity of heat, so phenomenon of overburning is avoidable.d) Perfect combustion is obtained in a nether burning region generating high temperture gas (temp<1350℃) which is divided into two streams: one passes through central part of calcining zone, upper calcining zone flowing to top of the kiln and comes cross the incomplete combustion gas coming from the upper burning region; another one is projected downward by the ejector in the nether burning region forming the cocurrent calcining zone.2. Cocurrent calcining is the key of calcination process in designing an annular shaft kiln which produces finished products lime. There are two air flows mixed called recyclegas in which the excess gas serves as a fuel for second combustion: high temperture gas come through material layer calcining limestone and enter to the Iow inner cylinder through equispaced air inlets; cooling air flow inhaled into the kiln is preheated by high temperature lime and enters into the Iow inner cylinder along with high temperture gas. The tempreture is around 800-90O℃ The circulating follows: inlets of Iow inner cylinder the top of inner cylinder--ejectors--material layers in the nether burning region-inlets of Iow inner cylinder.3. In the cocurrent zone, with material flowing downward, CaO shells gradually formed on surface of limestones reduce heat absorptivity.however. Low heating value fuels meet air creating combustion which provides moderate heat energy at the right time Consequently raw cores can keep decomposing without overbuming the CaO shells.4. There are two inner cylinders, the upper one is hung up the top of the kiln and the Iow one is positioned in the lower part of the shaft kiln. Both inner cylinder are made of rolled steel boiler plates with two layer. There is an annular space between two layers where is supplied with forced cooling air. Refractory material which contains magnesia alumina spinels high purity mullites, alumina bricks clay bricks and high density clay bricks are applied in both sides of the inner cylinders.5. From what has been introduced above, it can be seen that inner pressures of the kiln. air flows and tempretures are uniformity in the ringsection and the limestone layers which guarrentees homogeneity of lime calcination, improves quality of products and reduces unit consumption Thus, the annular shaft kiln has better adaptability to the lumpy material than a traditional lime kiln.