Engineering topics

Neal, Luke M.

Publications and source records attributed to Neal, Luke M..

4 records

DOE OSTI2023

Kinetic study of Ni-M/CNT catalyst in methane decomposition under microwave irradiation

Methane catalytic decomposition has been studied with catalysts that can attenuate the energy of electromagnetic waves to heat and drive the reaction. Herein, we report, for the first time, a comprehensive kinetic study of Ni-M (M=Pd, Cu, or Fe)-CNT catalysts under microwave irradiation. These binary metal alloy nanoparticles have been synthesized on multiwalled carbon nanotube support with solvothermal process. These catalysts showed incredible performance for both absorbing microwave energy and catalyzing the reaction to form carbon nanotubes and hydrogen. Ni-M-CNT has a reaction order of 0.74. 10Ni-1 Pd-CNT, 10Ni-1Cu-CNT, and 10Ni-1Fe-CNT have activation energies at 87, 75, and 69 kJ/mol. The investigation was carried out in a differential reactor. The results indicated that 10Ni-1Fe-CNT had the lowest activation energy due to the increase in microwave susceptibility. Here, this work pioneered the microwave catalytic methane decomposition field as well as paving the way for future electrification of CO x -free hydrogen production.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

DOE OSTI2022

Methane Catalytic Pyrolysis by Microwave and Thermal Heating over Carbon Nanotube-Supported Catalysts: Productivity, Kinetics, and Energy Efficiency

Methane catalytic pyrolysis, which is the reaction to produce hydrogen and carbon without emitting CO 2 , represents an approach for decarbonization using natural gas as an energy resource. In this work, the endothermic pyrolysis reaction was carried out under two heating scenarios: convective thermal heating and microwave-driven irradiative heating. The pyrolysis reaction was conducted at 550-600 °C over carbon nanotube-supported Ni-Pd and Ni-Cu catalysts. On both catalysts, an enhanced methane conversion rate was observed under microwave irradiation. The enhanced catalytic activity was hypothetically caused by the presence of free electrons in the carbon atoms within CNT that enabled the CNT support to absorb microwave energy effectively and to be heated efficiently by microwave. The microwave catalytic pyrolysis has shown improvement in kinetics, where the apparent activation energy dropped from 45.5 kJ/mol under conventional convective heating to 24.8 kJ/mol under microwave irradiation. When the methane conversion rate is increased by 37 %, the microwave power consumption only changed by 10.8 %. The research demonstrated the potential of transforming natural gas to clean hydrogen and value-added carbon in a more energy-efficient way. Process simulation and techno-economic analysis showed that potentially hydrogen minimum selling price of about $1 /kg H 2 could be achieved.

03 NATURAL GAS↗

DOE OSTI2021

A tailored multi-functional catalyst for ultra-efficient styrene production under a cyclic redox scheme

Abstract Styrene is an important commodity chemical that is highly energy and CO 2 intensive to produce. We report a redox oxidative dehydrogenation (redox-ODH) strategy to efficiently produce styrene. Facilitated by a multifunctional (Ca/Mn) 1− x O@KFeO 2 core-shell redox catalyst which acts as (i) a heterogeneous catalyst, (ii) an oxygen separation agent, and (iii) a selective hydrogen combustion material, redox-ODH auto-thermally converts ethylbenzene to styrene with up to 97% single-pass conversion and >94% selectivity. This represents a 72% yield increase compared to commercial dehydrogenation on a relative basis, leading to 82% energy savings and 79% CO 2 emission reduction. The redox catalyst is composed of a catalytically active KFeO 2 shell and a (Ca/Mn) 1− x O core for reversible lattice oxygen storage and donation. The lattice oxygen donation from (Ca/Mn) 1− x O sacrificially stabilizes Fe 3+ in the shell to maintain high catalytic activity and coke resistance. From a practical standpoint, the redox catalyst exhibits excellent long-term performance under industrially compatible conditions.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

DOE OSTI2020

Ethylene yield in oxidative dehydrogenation of ethane and ethane containing hydrocarbon mixtures

Methods and systems are provided for oxidative dehydrogenation of a hydrocarbon feed stream to produce a product stream with improved ethylene yield. The methods can include the steps of (i) combining a recycle stream with the feed stream to form a reactor feed stream, (ii) contacting the reactor feed stream with an oxide-based redox catalyst to produce the product stream comprising ethylene and one or more byproducts selected from the group consisting of methane, ethane, other byproducts, and mixtures thereof, and (iii) removing all or a part of the methane and ethane from the product stream to produce the recycle stream. Systems for the oxidative dehydrogenation (ODH) of a hydrocarbon feed stream are also provided to produce a product stream with improved ethylene yield. The systems and methods can include an oxide-based redox catalyst, such as Mg6MnO8, Cu6PbO8, and Ni6MnO8.

03 NATURAL GAS↗