Problems with centrifugal ammonia compressors’ impellers
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We installed a centrifugal ammonia compressor with 6 stages of compression: the inlet pressure is 0.25, and the outlet pressure is 0.7. When I opened the equipment, I noticed that the impellers in stages 1 to 4 gradually became thinner, with smaller cavities on them; however, the impellers in stages 5 and 6 suddenly became much thicker, much more so than those in the inlet stage. Why are the impellers at the outlet thicker than those at the inlet?
Compressors are designed to increase pressure; the further along, the higher the pressure becomes. To meet the requirements of a particular process, it is necessary to adjust the thickness of the impeller in order to achieve the desired pressure level.
The pressure at the outlet is high and the flow velocity is fast, which also causes significant wear and corrosion to the impeller; it’s meant to be resistant to wear and corrosion, right?
Compressors are designed to increase pressure; the further along, the higher the pressure becomes. The holes in the impeller become thinner, and the inlet at stage 5 may introduce more ammonia, resulting in an increase in the width of the impeller.