Maintaining the correct amount of solids in a precipitation circuit is paramount to optimal yield. The challenge lies in removing the right amount of product solids to ensure that the correct amount of solids is recycled. This is further complicated by other factors, such as:
- Planned and unplanned process variations;
- Delays of around two days between operator adjustments and the resulting eff ect on solids content;
- Not all the adjustments are available on the Process Control System (PCS). For example the removal to or recovery from hydrate storage are discrete field operations.
Historically the amount of solids to be removed was estimated by reviewing historical data and forecasting future process changes. This required a high degree of process experience and knowledge to determine the appropriate target.