Abstract
Heavy oil contains a significantly lower H/C ratio and higher quantity of organic heteroatoms and organo-metallic complexes than conventional light oil. Consequently, novel catalytic materials are needed to aid in heavy oil upgrading to remove the deleterious components and support the higher demand for low sulfur and higher value fuels. Heavy oil upgrading was studied using an inexpensive nickel-aluminum Layered Double Hydroxide (LDH)-derived Ni-enriched Mixed Metal Oxides (Ni-MMO) dispersed catalyst in a Baskerville autoclave. The conditions were set at 425 °C, initial pressure of 20 bar, 0.02 Catalyst-To-Oil (CTO) ratio, and a residence time of 30 min to mimick previously optimized conditions for in situ upgrading processes. The extent of the upgrading following catalytic pyrolysis was evaluated in terms of a solid, liquid, and gaseous phase mass balance, liquid viscosity reduction, desulphurization, and True Boiling Point (TBP) distribution. A typical in situ activated CoMo-alumina commercial hydroprocessing catalyst was used as a reference. It was found that the produced oil from dispersed ultrafine Ni-MMO exhibited superior light oil characteristics. The viscosity decreased from 811 to 0.2 mPa·s while the light naptha fraction increased from 12.6% of the feed to 39.6%, with respect to the feed. Using a thorough suite of analytical techniques on the petroleum coke product, including Thermogravimetric Analysis (TGA) and Scanning Electron Microscopy (SEM), a reaction mechanism has been hypothesized for the upgrading by dispersed Ni-MMO under both N2 and H2 atmospheres. Under a N2 atmosphere, the Ni-MMO, generated by the in situ thermal decomposition of the LDH, demonstrate a preferential asphaltene and poly aromatic adsorption mechanism, generating a poly aromatic mixed oxide-coke precursor. While using Ni-enriched mixed oxides under a reducing H2 atmosphere, hydrogenation reactions become more significant.
Highlights
Petroleum demand is expected to grow over the coming decades before being phased out by renewable alternatives
The intercalation of Ni and Al into the brucite-like layer was confirmed with a molar ratio at 3.3:1. This demonstrates the successful enrichment of nickel into the Layered Double Hydroxide (LDH) during the coprecipitation synthesis method
A high-surface area Ni-enriched Mixed Metal Oxides (Ni-MMO) catalyst was used as an ultradispersed variation of the fixed-bed production liner, simulating upgrading with a different contacting pattern
Summary
Petroleum demand is expected to grow over the coming decades before being phased out by renewable alternatives. There are an estimated 8 trillion barrels of heavy oil and bitumen remaining in Canada and Venezuela.[2] primary production in these petroleum reservoirs is limited by both the physical and chemical properties of the oil. These unfavorable properties constitute an excessive viscosity, which significantly limits the flow rates of production wells. Enhanced Oil Recovery (EOR) techniques are employed to partially upgrade these heavy oils. High temperatures may be achieved in the reservoirs as a result of thermal techniques, with a notable example Toe-to-Heel Air Injection (THAI) leading to temperatures exceeding 450 °C and peaking up to 600 °C in laboratory simulations.[3,4] This is an adequate temperature to promote catalytic upgrading and as such has lent itself to the development of an in-well catalyst interface otherwise known as CAtayltic upgrading PRocess In-situ (CAPRI) comprising a fixed bed of hydroprocessing catalysts within the annulus of the production liner
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