What is the reason for granulation in the furnace front chamber?
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Our large furnace is the type with a pre-chamber; these days we have noticed uneven temperatures in the pre-chamber, with drops in temperature occurring at times. In severe cases, it becomes difficult to feed material near the feeding port. The temperature is high in the rear area and low in the front area, and the sulfurization state of the material is not good; granulation occurs in the pre-chamber. I’ve guessed a few possibilities, but I’m not sure; please help analyze the reasons
How is the moisture content of the feed controlled? The accumulation of material in the front chamber is also a cause of uneven temperature.
There are about 9 levels of moisture content when entering the furnace. Granulation occurs in the front chamber; the material has poor mobility as it moves from the front chamber toward the rear area, remaining essentially stationary, and thus accumulates in the front chamber to form granular particles
Coarse grains are formed, which is also related to an inappropriate air-to-material ratio; an inappropriate air-to-material ratio has led to a phenomenon of air separation； Another cause is a high content of low-melting-point metals such as lead and zinc.
The lead and zinc contents are not low; the lead level ranges from 0.1 to 0.3, while the zinc oxide level is around 0.4 to 0.5
In addition to excessive moisture in the feed material, feeding too quickly and a rapid drop in furnace temperature can also lead to poor fluidization; the condition of the air nozzles also affects the local level of fluidization. Use a steel pipe to inspect the furnace, to check the condition of the air cap layer in the low-temperature area Consider the last few issues as a whole, take measures; if that doesn’t work, material removal will be necessary.