(240c) Programmable Volumetric Temperature Control with Inductively Heated Metamaterial Reactors

The electrification of thermochemistry presents a direct route to decarbonizing heavy industry processes. There exist many routes to electrified heating, and amongst these, magnetic induction presents unique advantages in scaling due to the intrinsically volumetric nature of magnetic fields and the ability of induction to transduce large voltages on a drive coil to large currents in a susceptor. Recently, we proposed and demonstrated the inductively heated metamaterial reactor, which is a structured reactor concept in which the reactor baffles are geometrically tailored to support a volumetric induction heating profile and a heating efficiency of nearly 100%. While promising, the concept was limited to a fixed system featuring uniform axial heating profiles, which is suboptimal. Electrification concepts that can enable tailored axial temperatures can push the kinetics and conversion limits of thermochemical reactors.

In this talk, I will present two concepts in which the axial temperature profile within a metamaterial reactor can be customized to maximize conversion for endothermic gas reforming processes. In the first, we show that the metamaterial susceptor can be tailored to support a precise, preprogramed heating profile that is engineered to produce an ideal temperature profile. The heating profile is customized by varying the axial conductivity of the baffle, which comprises a discrete series of segments with high spatial resolution. Using energy balance relations, the heating profile required to produce ideal isothermal temperature profiles is specified by a machine learning-driven inverse design procedure that accounts for heat transfer and kinetics. We show that our axial metamaterial profile can be precisely tailored to enhance temperature uniformity in a reactor that performs the reverse water gas shift reaction, and that conversion can be enhanced by nearly 10% compared to uniformly heated reactors with the same maximum temperature.

In the second concept, we present the digitally programmable metamaterial reactor, in which the current profile produced in the drive coil is actively varied to control the temperature profile. In this idea, the drive coil is specified as a series of loops that are each impedance loaded with independent control. The series of loops collectively produce a magnetic “supermode” that produces a tailored volumetric heating profile. Importantly, temperature measurements from fiber optic temperature sensors within the reactor can be used in a feedback loop to actively tune the impedance load on each loop in a manner that controls the supermode profile and subsequent volumetric temperature profile. We show theoretically and experimentally that our programmable reactor can support a wide dynamic heating range, with a factor of ten variation in heating magnitude within the heating profile, and that it can be adapted to produce isothermal temperature profiles for the reverse water gas shift reaction operating under different maximum temperatures and gas flow rates.