タイトルまたは説明

Annular Shaft Kiln originated in the sixty's of last century, Germany, formerly known as Beckenbach Annular furnace charge zone lime Vertical kiln, is a kind of lime vertical kiln, with two shafts, inner shaft and outer shaft. The raw material is calcined between the inner and outer shaft space.
Annual Shaft kiln technological process
Annual Shaft kiln inner structure from top to bottom is pre-heating zone, upper counter-follow calcining zone, lower parallel-follow calcining zone, and cooling / discharge zone. Raw material is screened firstly, then transferred to the top of the kiln by the hoisting hopper, and then feed into the kiln body by the rotary distributor evenly. Preheated raw material moves into the upper calcining zone along the annular furnace charge space in where the raw material is effective in decarburization. The almost-finished lime in the upper calcining zone moves into the lower calcining zone for effective homogeneous, then moves down to the cooling zone, finally drops into the lime silo under the kiln by lime pusher platform. The finished lime transferred to the storage by the belt conveyer.
Main system equipment
A) limestone feeding and distributing system: lime stone hopper, weighing device, hoisting hopper, cable, electric winch, feeding device and rotary distributor, also limit switch, signal transmitter, hydraulic cylinder and hydraulic station.
B) lime discharging system: pusher platform, pusher rod, hydraulic cylinder and lime silo.
C) fuel distribution system: the fuel manifold, distribution branch pipe, related instruments and valves, online low calorific value analysis instrument.
D) exhaust system: exhaust pipe, exhaust fan (1set), bag dust collector, dedust fan (1 set), also relative  valves, instrumentation, discharge chimney.
E) driving air system: driving air pipe, driving air blower (2 sets), heat exchanger, injector, also relative valves, instrumentation.
F) the inner shaft cooling air system: pipeline, blower (2 sets, 1  for use, 1 for preparing), also relative valves, instrumentation.   
G) Combustion system: fuel and combustion pipeline, regenerative burner, UV (ultraviolet) flame detector, also relative valve, instrument.
H) Control system: MCC (motor control center), PLC, PC, and printer.
 
From the above system equipment, Annual Shaft kiln system is relatively simple, blowers are only six sets, and the permanent work ones are only five sets. This will bring the following advantages: 1, the system is simple, easy to operate; 2, less movable parts, saving electric energy; 3, low failure rate, high utilization rate, low maintenance cost,  and low spare parts consumption.
 
Technical Characteristics
 
 1, it effectively reduces the layer thickness of raw material, the permeability of the kiln body is better;
2, raw material stone has a complete tumble during across the arch bridge, the calcination is more uniform;
3, the calcination flame isn't directly in contact with the material because of the existence of the combustion shaft,  the heat transfer is mainly through the way of heat radiation, the fuel has better adaptability;
4, heat recovery is finished through effective heat exchange mechanism, which reduces the heat consumption;
5, counter flow calcination and parallel flow calcination are in one kiln body, which effectively solves the problems of under-burnt and over-burnt, the lime activity is improved;
6, it has high degree of automatic control, it can realize fully automatic control;
 7, the productivity elastic range is large, up to *0% ~ **0%; 
8, the whole kiln body is a negative pressure operation, in favor of calcination and more environmental protection;
 

Technology improvement
      Heat exchanger structure makes some improvements, making the pipeline dredging and replacement more convenient
      by adopting the special material, the gas sampling tube have been improved, which makes the measuring instrument no longer blocked
      it changes only one temperature measuring point into 6 (or 7) temperature measurement points in the recycle air outlet from the old kiln to the improved new kiln, which will benefit the users accurately know the kiln calcines completely or not
      Arch bridge refractory material makes further improvement , it changes the inner shaft brick from two sides occlusion to four sides occlusion, which makes the overall kiln lining longer life
      Flameless combustion technology
Technical specifications
      Daily output: **0 tons to **0 tons
      Fuel: coal powder, natural gas, coke oven gas, converter gas, high / coke mixed or other mixed coal gas( the mini low heating value: ***0Kcal/Nm3)
      Limestone particle size: *0mm to *0mm (large, small granularity ratio 1: 2)
      Heat consumption: between **0~**0kcal/kg lime
      power consumption: *8Kwh/t lime
      Lime quality: the activity >**0ml (4NHCI, 5 minutes) CO2  residue≤ 1.5%;