Phone:
0086 28 87573647
+86 19150187139
How to Decide Whether to Use 4" or 8" Membrane Elements in a System
According to the membrane company's design guidelines, the recommended average permeate flow rates are 8-14 gfd (using surface water as the feed water source), 14-18 gfd (using groundwater as the feed water source), and 20-30 gfd (using permeate from the first-stage reverse osmosis system as feed water to the second-stage reverse osmosis system).
Based on these design guidelines, the minimum permeate flow rate for a single 8040 membrane element is 0.46 t/h (using surface water as the feed water source), 0.80 t/h (using groundwater as the feed water source), and 1.15 t/h (using permeate from the first-stage reverse osmosis system as feed water to the second-stage reverse osmosis system). Theoretically, 8040 membrane elements can be used when the system permeate flow rate exceeds these values. However, the decision to use 8040 membrane elements must also consider factors such as the system's recovery rate requirements, whether concentrate recirculation is permitted, the system's footprint, the cost of the pressure vessel, and the overall economic viability of the system.
Based on a comprehensive balance of various factors, it is generally believed that 8040 membrane elements are more suitable for reverse osmosis systems with a capacity of 5t/h or above, while 4040 membrane elements are more suitable for systems with a capacity of less than 3t/h. For reverse osmosis systems with a capacity of 3-5t/h, either 8040 or 4040 membrane elements can be used.
