Problem with suspended material in the slaked lime powder silo for boiler desulfurization!
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Our company’s boilers use wet flue gas desulfurization, and for this purpose there is a 70 m3 slaked lime powder silo. A fluidizing air system is installed at the funnel of the silo to prevent the slaked lime from caking or remaining in suspension. The equipment connected below the silo’s bottom funnel is arranged in the following order: straight short pipe – circular compensator – elbow fitting of different sizes – manual slide gate – electric slide gate – star feeder – lime storage tank； Due to the flowing air provided above the funnel, this section prevents slaked lime from caking or remaining in suspension; however, nowadays caking and suspension occur frequently at the manual sliding door located at the lower part of the funnel. I would like to ask if any of you have encountered this phenomenon? Is there any good way to deal with this? The straight section at the lower part of the funnel has a diameter of DN300; an inclined DN80 maintenance access hole is provided in this straight section. When operators insert a iron rod into it, it feels as though there is a bucket on an iron plate, making it impossible to insert slaked lime. The length from the lower part of the funnel to the storage tank is approximately 1.2 meters
A solution is provided for reference. A vibration motor is installed on the wall of the discharge funnel; its operation is synchronized with that of the feeder. That is, when the feeder operates, the vibration motor also operates simultaneously to quickly discharge the slaked lime ； When the feeder stops, the vibration motor also stops, preventing the accumulation of slaked lime inside the cylinder.
Timed control of the motor’s start and stop does save energy, but what we are addressing are the problems of caking and hanging material. If the feeder stops, the vibration motor also stops simultaneously (it is preferable for it to stop after a delay), which allows the contents inside the cylinder to be emptied completely, preventing caking and residual material. Of course, it would be better if the start and stop times of the motor during the feeding period could be controlled. :)
I think it’s because the slaked lime absorbs moisture and then reacts with carbonic acid, causing it to clump together. Solution: It is recommended to install electric heating tapes for insulation in the straight pipe section between the funnel and the valve, to ensure that the slaked lime remains dry; this should resolve the issue.