Heavy Oil Without Coke: Removing Asphaltenes Before Coking with Vacuum Separation and TEGA

Venezuela holds some of the largest heavy-oil reserves in the world, and the way that oil is processed leaves a mountain behind it. Orinoco oil is thick and sulfurous. It is heated, blended with lighter oil, stripped of its distillate fractions and the heavy residue is sent to delayed coking, where up to a third of the residue by mass leaves as petroleum coke carrying sulfur, vanadium and nickel. Stocks of this coke at the port of Jose are estimated at 15–30 mln t; exports stalled after a fire in 2009, sanctions complicate sales and new coke is added every day. This preprint proposes to attack the cause rather than the pile: remove the asphaltenes, the molecules that turn into coke, before coking. The proposed scheme has 3 steps. Feed is dehydrated; ARBOK-VC separates the light fractions under deep vacuum without hydrogen or consumables, at an electricity consumption of 1–2.5 kWh/t against 15–25 kWh/t at a conventional refinery; the heavy phase is passed over TEGA, the graphene-like expanded graphite of ARBOK, where the aromatic cores of asphaltenes adsorb on the graphitic surface and carry vanadium and nickel with them. The product is a deasphalted oil for refineries and a loaded TEGA phase that can be processed further. Each percentage point of additional yield is 10 kg of usable oil per tonne of heavy oil; the TEGA dose is 0.1–0.5% of the feed, that is 1–5 kg per tonne. Published work supports the individual links of the chain but no study tests TEGA or graphene on heavy residue, so the preprint closes with a 2-series R&D programme on real Orinoco residue.