An apparatus, process and system for treating a hydrocarbon feedstock having a specific gravity differential between components of the feedstock is disclosed and includes a treatment vessel having an inlet for receiving the feedstock. A primary separation container may be located in the treatment vessel to accumulate feedstock to cause a low specific gravity portion of the feedstock to separate and rise to an upper surface of the accumulated feedstock. A secondary separation container may be located in the treatment vessel to receive the collected low specific gravity portion from the primary separation container, to accumulate the collected low specific gravity portion to cause hydrocarbon products to separate and rise to an upper surface of the accumulated low specific gravity portion of the feedstock, producing a hydrocarbon product stream at a product outlet. The operating pressure of the treatment vessel may be regulated to remain within a desired range.