Figs 4 and 5 show that within the pressure range, pure PSU membrane presented a decreasing trend of permeance with increasing
feed pressure. Here in the Fig, the CO2 and CH4 permeance decreased from 7.40+-0.12 to 3.87+-0.2 GPU and 1.05+-0.05 to 0.34+-0.1 GPU with an increase in the pressure from 2 to 10 bar for pure PSU membrane.
Process data via DuPont's innovative, proprietary software, Wave, shows how the pre-treatment stage in the system minimizes membrane fouling, which in turn lowers required system
feed pressure and the need for frequent membrane cleanings.
Variable
feed pressure is applied through a motor/gearbox/chain combination providing 30,000-lb.
Interestingly, PSf/Ti[O.sub.2] 3 wt% did not have C[H.sub.4] permeability at 1 bar
feed pressure. While, the amount of C[O.sub.2] permeance at same pressure for mentioned membrane was 0.26 GPU.
The reason to cool the screw this way is to prevent polymer from sticking to its surface until some
feed pressure is developed to "clean" the screw by conveying material forward.
The
feed pressure as well as other parameters such as operational temperature and properties of the membrane has significant effect on the performance of SWRO process.