DEMINERALIZATION STAGE:
The plant is conceived to deliver 4-6 m3/h of permeate stream with an electrical conductivity ≤5 µS/cm, starting from 6-8 m3/h of raw water with a maximum concentration of ions of about 375mg/l (TDS). This choice allows to cover most of the civil/industrial applications where it is expected to draw water from the local network (2 bars at least) by ensuring the production of high-quality demineralized water (low conductivity) for industrial uses and, in particular, for the production of high purity AdBlue®.
The grade of water is based on the definition of water grade 3 of ISO 3696.
[Reference: ISO 22241-1:2006(E)]
During this phase the feed water passes through 3 semi permeable membranes under pressure. As a result, water is split into two streams:
- The permeate (Demineralized water)
- The concentrate (A concentrated solution of impurities)
The key functions and components of this stage are:
- Flushing management (tank capacity of 500 liters approximately).
- Dosage of antiscalant (scale inhibitor) and dechlorinating product in to a storage tank.
- Pre‐filtration of the feed water through a couple of filter cartridges.
- Pressurization by vertical multistage centrifugal pump (HPP).
- Filtration through osmotic membranes.
- In‐ line conductivity measurement system that is designed to control the production process.
- Permeate and concentrate streams management (delivery/recirculation).