Preheater clogging analysis
Date：2019-07-18 15:03 Source：未知Views:
There is a common problem in the production process line of pre-decomposing kiln, which is the kiln tail system -- preheating system and decomposing furnace skilling, accumulating and blocking.Once the skin clogging occurs in the preheating system, the thermal working system is disrupted, which seriously affects the quality of cement production. Moreover, it is difficult to resume production if the skin clogging is handled, and even worse, human casualties are caused by the clogging.
How to correctly understand and serious about this phenomenon of objective existence, know it will bring danger to the production, and through some necessary means of control and certain process handling measures, and scientifically forecast and prevention, is to ensure production run smoothly, ensuring the safety of process facilities, the key to giving full play to the advantages of the system.
1. Formation of skin
The most prone to skin formation in the predecomposing kiln are the smoke chamber at the end of the kiln, the discharging slope, the shrinking mouth at the end of the kiln, the discharging pipe of the lowest two-stage cylinder, and the places in the decomposing furnace.Skilling reduces the effective cross-sectional area of the ventilation passage and increases the resistance correspondingly, which affects the ventilation of the system and increases the draught of the main exhaust fan.When the crust collapses, it is also prone to blockage.
2. Blockage symptoms of kiln tail system
The blocking of preheater can be judged in central control room and on site.In normal production, the control parameters of the preheater system are very regular from the operation screen of central control: the negative pressure decreases step by step from top to bottom, and the temperature increases step by step, and the difference between the two columns is very small.
However, when blocking occurs in a column:
(1) take the plugging site as the boundary, and the negative pressure value of many places above the plugging site rises sharply;Positive pressure appears below the plugging site;There is a phenomenon of ash in the place of punching hole and exhaust valve.
(2) the negative pressure of kiln head is insufficient, and positive pressure will be generated in case of serious problems, and fire will be emitted from observation holes and other places.
(3) the exhaust fan of kiln tail, primary cylinder outlet, decomposition furnace outlet and kiln tail are abnormal in many places.
(4) the cone negative pressure of the blocked preheater drops sharply, even reaches or approaches zero pressure.
(5) abnormal drop of blanking temperature.
(6) reduce the materials entering the kiln.
Usually, the occurrence of 3 or more of these symptoms indicates that the kiln tail system has been blocked, and measures should be taken in time.
Clogging may occur in many parts of the pre-decomposition system, but it mainly occurs in the fifth and fourth stage cyclone cylinders.If not handled in time, the blanking pipe at all levels and inside the flap valve can sometimes block the preheater cone from the blanking pipe or even the whole cyclone tube.It is decomposing furnace and its slope, connecting pipe, deformation or diameter pipe, etc.
3. Jam time
In terms of time, most of the blockage occurred shortly after ignition, kiln operation was abnormal, and the thermal system of the system was unstable.In addition, the system accident is many, when frequently starts and stops the kiln, because the wind material collocation is improper, the coal powder is not completely burnt and other external causes, also very easy to cause the blockage.