Northshore CES1490: FCC slurry de-ashing

The refinery collected slurry from two FCC units in a receiving tank and returned the oil to catalytic cracking. Catalyst fines in the slurry created an ash burden, and the customer's stated operating objective included maintaining acceptable flue-gas particulate performance when the material was recycled. The refinery wanted to improve slurry quality using its existing receiving and additive systems.

The acceptance criteria addressed the tank's usable oil zone, with samples taken at upper, middle and lower levels above the high draw-off point. Settling time and the expected incoming-solids range were also included. That gave the plant a defined basis for deciding whether treated slurry was suitable for the intended route, rather than judging the result from a clean-looking top sample alone.

Northshore CES1490 is Cestoil's slurry settling aid. Its role in this application was to promote separation of fine solids so that clarified oil could be withdrawn above the settled material. The refinery metered the product into the slurry receiving line through its existing additive system, mixed it with the incoming slurry and allowed separation in the receiving tank.

The program was evaluated against the actual slurry and the available settling arrangement. Incoming solids, additive delivery and tank operation all affected the context in which the ash result was assessed. For a comparable site, the important question is whether the treatment can meet the required quality within the settling time and draw-off arrangement the refinery can provide.

The initial tank results did not meet the agreed ash requirement. Cestoil replaced the first batch and worked with the plant on laboratory settling tests before dosing resumed. This development is part of the case's technical value: the final reported performance followed a corrective step and confirmation testing, rather than uninterrupted success from the first application.

The laboratory work helped confirm treatment conditions on the plant's slurry. Subsequent tank monitoring followed the program through later deliveries and winter operation. The distinction between the initial results, laboratory confirmation and later tank observations is preserved in the full report so that a reviewing team can see how the application developed.

The refinery assessed ash at multiple tank levels and after defined settling periods. This approach helped determine whether the usable zone of the tank had improved, rather than relying on a single favorable sampling location. Later records included observations from upper, middle and lower positions as available for each sampling event.

The report also lists solids measurements alongside ash in parts of the operating record. Those values should retain their original labels: ash and measured solids are related quality indicators but are not interchangeable test results. A comparable program should agree on the analytical method, sampling levels and acceptance calculation before treatment starts, so that the operator and supplier judge performance on the same basis.

The case offers a practical way to evaluate whether an existing slurry tank can deliver a more suitable recycle stream. It emphasizes the quality of the oil that can actually be withdrawn, the time available for settling and the need to follow incoming-solids variation. Laboratory screening and plant monitoring serve complementary purposes in that assessment.

The report does not quantify a monetary saving for this refinery. An economic assessment would use the volume treated, additive consumption, the value of the intended recycle or alternative disposition and any relevant operating constraints. Tank capacity, settling time and solids-removal arrangements would also need to fit the refinery's operating plan. Those inputs help connect the measured ash improvement to a realistic commercial decision.