Experimental Investigation of Metal-Based Calixarenes as Dispersed Catalyst Precursors for Heavy Oil Hydrocracking

Slurry-phase hydrocracking utilizing metal-containing oil-soluble compounds as precursors of dispersed catalysts is an effective approach for heavy oil upgrading. We propose applying metal-based p-tert-butylcalix[6]arene (TBC[6]s) organic species as dispersed catalyst precursors to enhance catalytic hydrogenation reactions involved in the upgrading of vacuum gas oil (VGO). Co- and Ni-based TBC[6]s were synthesized and characterized by SEM-EDX, ICP, XRD, and FT-IR. The thermogravimetric and calorimetric behaviors of the synthesized complexes, which are key properties of dispersed hydrocracking catalysts, were also explored. The experimental evaluation of the synthesized catalyst precursors show that the synthesized metal-based TBC[6] catalyst precursors improved the catalytic hydrogenation reactions. A co-catalytic system was also investigated by adding a commercial, first-stage hydrocracking supported catalyst in addition to the dispersed catalysts. The naphtha yields increased from 10.7 wt.% for the supported catalyst to 11.7 wt.% and 12 wt.% after adding it along with Ni-TBC[6] and Co-TBC[6], respectively. Mixing the metal-based precursors resulted in elevated yields of liquid products due to the in situ generation of highly active Co–Ni bimetallic dispersed catalysts.This research was funded by Deanship of Research Oversight and Coordination (DROC) at King Fahd University of Petroleum and Minerals (KFUPM), grant number DF181018

Electrochemical Reduction of CO2 to Ethylene with 32% Lower Energy at 80% Lower Cost via Coproduction of Glycolic Acid

We are in a race against time to implement technologies for carbon capture, conversion, and utilization (CCU) to create a closed anthropogenic carbon cycle. Renewable energy powered electrochemical CO2 reduction (eCO2R) to fuels and chemicals is an attractive technology in this context. Here, we demonstrate a strategy to drive economic feasibility of eCO2R to ethylene (C2H4), the largest produced organic chemical, by coupling with glycerol oxidation on anode. Our gold nano-dendrite anode catalyst demonstrated very high activity (J ~377 mA/cm2 at 1.2 V vs reversible hydrogen electrode) and selectivity (~50% to glycolic acid (GA)) for glycerol oxidation. The co-electrolysis process demonstrated record high selectivity of ~60% for C2H4 production at a very low cell voltage of ~ 1.7 V, translating to 32% reduction in required energy compared to conventional eCO2R with water oxidation reaction on anode. The experimental results were complemented with a detailed technoeconomic analysis that indicated economic feasibility will depend on several factors such as price of organic feed, selectivity of anode electrode, market value of chemicals produced and most importantly cost of separation and purification. Our results indicate that C2H4 produced via conventional eCO2R would require electricity price to plummet to 2H4 and GA will help reduce C2H4 production cost by ~ 80% to ~1.08 $/kg, reaching cost parity at electricity price of 5 cents/kWh. This study may trigger research efforts for design of electrochemical processes with low electricity requirement using cheap industrial waste streams. </p

Seawater Electrolysis for Hydrogen Production: A Solution Looking for a Problem?

As the price of renewable electricity continues to plummet, hydrogen (H2) production via water electrolysis is gaining momentum globally as a route to decarbonize our energy systems. The requirement of high purity water for electrolysis as well as the widespread availability of seawater have led significant research efforts in developing direct seawater electrolysis technology for H2 production. In this Perspective, we critically assess the broad-brush arguments on the research and development (R&D) needs for direct seawater electrolysis from energy, cost and environmental aspects. We focus in particular on a process consisting of sea water reverse osmosis (SWRO) coupled to proton exchange membrane (PEM) electrolysis. Our analysis reveals there are limited economic and environmental incentives of pursuing R&D on today’s nascent direct seawater electrolysis technology. As commercial water electrolysis requires significant amount of energy compared to SWRO, the capital and operating costs of SWRO are found to be negligible. This leads to an insignificant increase in levelized cost of H2 (2) and CO2 emissions (<0.1%) from a SWRO-PEM coupled process. Our analysis poses the questions: what is the future promise of direct seawater electrolysis? With an urgent need to decarbonize our energy systems, should we consider realigning our research investments? We conclude with a forward-looking perspective on future R&D priorities in desalination and electrolysis technologies