Atmospheric pressure granulation technology
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Who has any insights on granulation using atmospheric pressure nozzles? Let’s discuss it
Currently, urea is generally granulated at atmospheric pressure, but care must be taken to prevent nozzle clogging.
These days, urea is generally granulated under pressure. It is pumped from the melt pump into the granulation tower and goes straight to the nozzles, with no pressure-reduction equipment in between; therefore, it is granulated under pressure, and it cannot be considered granulation at atmospheric pressure
Ladies and gentlemen, the equipment used in our factory operates at atmospheric pressure, which means that it’s very prone to clogging! Impurities as small as possible can cause blockages, while operating under pressure can help avoid this (of course, to some extent). The equipment is provided by the Beijing Aerospace Power Research Institute and Beijing Aerospace Petrochemical Technology Equipment Engineering Company!
High-tower granulation is essentially carried out under atmospheric pressure; the nozzles are located at a high altitude (60–100 meters). The outlet of the melt pump leads to the top of the granulation tower, which helps to reduce pressure drops. In addition, there are buffers in front of the nozzles, ensuring that the pressure remains at atmospheric levels. The nozzles have numerous openings through which the liquid is sprayed into the atmospheric space, further eliminating any residual pressure. The buffer in front of the nozzle is a device that operates at atmospheric pressure; if pressure builds up, the flange of the buffer will leak. Careful control is necessary during operation to prevent blockage of the nozzle.
For oil granulation, the process used is the granulation technology developed by Chengde Oil Co., Ltd. Factors such as the melting point of the oil, moisture content, and other elements play a role; what’s crucial is the heating effect in the pipelines. It is necessary to check the nozzles during startup and shutdown, and the oil inside these nozzles must be cleaned thoroughly. Before starting up, steam should be used to melt the oil inside the nozzles. The control of blowers and exhaust fans is also very important.
Granulation in the granulation tower is carried out at atmospheric pressure, and it is prone to issues such as nozzle clogging and urea sticking to the tower; care should be taken during operation
Urea granulation is mostly carried out under normal pressure, with the main focus being on preventing blockages during the process; attention should also be paid to the abrasion of nozzles during maintenance.
Our factory uses centrifugal nozzles, and they work very well
Small-particle urea is produced through atmospheric-pressure spray granulation; be careful not to make it too liquidy and to avoid clogging the nozzles； Large-grain urea is produced by fluidized bed granulation.
The nozzles in our factory also get clogged, and there’s no good solution for it.
How to solve the problem of clogged nozzles? Should I purge them?
Large-grain urea has also been used more in recent years, and the problem of clogging is not as severe
We also gave it a try and found that increasing the diameter of the nozzle makes it less likely to get clogged