Filtration and Dewatering - Customer-site case study
TF238 dry screw vacuum pump for phosphogypsum dewatering in Nanzhang
In May 2025, a phosphate chemical plant in Nanzhang, Hubei, China installed one TF238 dry screw vacuum pump on a vacuum belt filter for phosphogypsum dewatering. The pump was specified for continuous operation at 30,000 Pa(a) and 183 m3/min.
Installed pump
One TF238 dry screw vacuum pump
Working pressure
30,000 Pa(a)
Required volumetric flow rate
183 m3/min
Previous vacuum system
Two 2BEC60 water ring vacuum pumps
Project background
The May 2025 order was part of a production-line expansion. It followed a successful test at another plant in the same group in May 2024. The existing line used two 2BEC60 water ring vacuum pumps for its vacuum duty.
With acidic liquid in the process, electricity use and the handling of the water-ring working liquid added to the operating load. The earlier group test gave the customer a basis to select the dry screw package for the new line.
Vacuum duty on the belt filter
At this plant, phosphate rock reacts with sulfuric acid to produce phosphogypsum slurry. After solid-liquid separation and washing, the slurry passes to a vacuum belt filter for dewatering. The resulting filter cake then moves to managed stockpiling or further utilization.
During washing, phosphorus- and fluorine-containing components are removed from the phosphogypsum for recovery and reuse. The TF238 draws vacuum for the belt filter during dewatering.
Material feeds continuously across the filter. The pump package maintains the required vacuum until the line is stopped manually. This project used one TF238 at 30,000 Pa(a) with a required volumetric flow rate of 183 m3/min.
Conditions reviewed at the pump inlet
Acidic liquid carryover
The gas stream could carry acidic liquid from the process. The protection arrangement was set around this line's liquid condition and carryover pattern.
Fine solids at the inlet
Fine particles could travel with the carried liquid. A vacuum buffer filter tank and inlet filter were installed ahead of the pump to limit what reached it.
Materials and discharge
SS316 was used for process-contact parts, and the discharge included an exhaust silencer. Both choices followed the conditions confirmed for this installation.
Customer-reported operating reference
On this production line, the customer reported that the previous two-pump water-ring system used about 500 kW. The TF238 has a theoretical power of 185 kW, while the customer reported operating power consumption of about 135 kW.
Based on the customer's electricity-cost calculation, the estimated annual saving was nearly RMB 2.2 million, with the purchase cost recovered in about one year. The estimate is specific to this line and the two-pump water-ring system it replaced, so a similar project should be assessed against its own operating duty and electricity price.
Customer feedback
“SC Air Power Tech's dry screw pump cost more upfront, but one unit now replaces the two water ring pumps we used before. That makes maintenance easier, and the lower power consumption was a welcome surprise. It also helped us meet the carbon-neutrality target set by our management.”
Anonymous project lead, Nanzhang phosphate chemical plant. Portrait adapted for privacy. Edited translation.
FAQ
What's next
Need a vacuum belt-filter dewatering review?
Send the working pressure and required volumetric flow rate first. Process liquid, carryover, inlet protection, operating pattern, and site conditions can be confirmed during follow-up.
