The pumps were needed to evacuate gypsum cake resulting from the filtration of phosphoric acid slurry.
The project presented a challenge because the gypsum produced by the reaction between phosphate rock and sulfuric acid must be separated and removed from the mainstream phosphoric acid production process. The gypsum cake is collected from the filter, slurrified and then pumped to stacks. Over a period of time, the height of the stacks increases, and more energy is required to continue discharging the slurry. In this case, additional booster pumps were needed.
After analysing the slurry properties and operating conditions, Sulzer opted for a heavy-duty slurry pump type EMW in metal alloy construction.
The main characteristics of the solution include a heavy-duty slurry pump type EMW350MS, full-diameter closed impeller and low rotating speed and wear-resistant material (FC1) with corrosion-resistant properties.
A heavy-duty slurry design is intended to withstand erosion and offer durable performance despite wear. The wear is said to be mitigated by an appropriate combination of hydraulics and materials. In practice, this means a lower rotating speed, correct position of the nominal flow with regard to the best efficiency point, and selection of a wear-resistant material within the range of high chromium iron.
Alaa Abuissa, area sales manager at Sulzer, said: “The project was identified as highly critical. Therefore, we started a technical exchange with the customer to identify the key parameters and operating conditions. Also, some field tests were made to define the best technical proposal. The schedule for the manufacture of six (6) EMW350M slurry pumps was very tight. We delivered the pumps on time early 2021 and our customer is very satisfied with their performance.”
In this case, Sulzer considered the composition of the slurry and the operating conditions. The company estimated that the first factor to be considered was the erosive character of the application. Sulzer proposed corrosion testing at the site to confirm the suitability of the pre-selected materials.