Effect of Flow Rates on Operation of a Solar Thermochemical Reactor for Splitting CO2 Via the Isothermal Ceria Redox Cycle

Hathaway, Brandon J.; Chandran, Rohini Bala; Sedler, Stephen Joseph; Thomas, Daniel E.; Gladen, Adam C.; Chase, Thomas R.; Davidson, Jane H.

doi:10.1115/1.4032019

Cited by 21 publications

(31 citation statements)

References 21 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The authors reported thermal efficiencies up to 5.22%. More recently, Fosheim et al evaluated CLDRM in a solar cavity receiver integrated with highly effective gas‐phase heat recuperation; the reactor prototype consists of a concentric array of coaxial alumina tubes that each contain a packed bed of ceria and alumina reticulated porous ceramic. Here, ten isothermal chemical‐looping cycles were consecutively performed with 336 g of ceria, or 1/6th of the total reactor capacity, at two tube temperatures (i.e., 955 and 1000 °C) and the following gas flow rates: 5.5

{μ mol}_{{CH}_{4}}

s −1 g −1 (diluted with 1.7

{μ mol}_{N_{2}}

s −1 g −1 ) and 7.1

{μ mol}_{{CO}_{2}}

s −1 g −1 for reduction and oxidation, respectively.…”

Section: Introductionmentioning

confidence: 99%

Solar Reactor Demonstration of Efficient and Selective Syngas Production via Chemical‐Looping Dry Reforming of Methane over Ceria

et al. 2020

View full text Add to dashboard Cite

Technologies that facilitate the conversion of CH4 and/or CO2 with concentrated sunlight provide a viable strategy for storing solar energy in the form of liquid fuels and reducing anthropogenic greenhouse gas emissions. Herein, a scalable prototype receiver‐reactor is developed to experimentally demonstrate the chemical‐looping, dry reforming of methane over ceria with simulated concentrated solar radiation. Optimal operating conditions are identified by investigating wide ranges of parameters like temperature, gas flowrate, inlet CH4 concentration, initial oxygen nonstoichiometry, and particle size. Ultimately, a selectivity to H2 and CO of greater than 0.93 is observed at reactant conversions of 0.69 and 0.88 for CH4 and CO2, respectively. As a result, the calorific value of the products relative to the reactants is upgraded, and a solar‐to‐fuel conversion efficiency of 10.06% is attained, higher than the previously reported record of 7%. Near‐perfect selectivity to syngas is achieved by operating with low reactant residence times, and if reactions were initiated over oxygen‐deficient ceria. Reactant conversion is enhanced through a reduction in particle size, which enables more rapid kinetics via an increase in surface oxygen availability. Stable performance is demonstrated over 10 consecutive redox cycles under conditions that maximized efficiency for the system presented herein.

show abstract

{μ mol}_{{CH}_{4}}

s −1 g −1 (diluted with 1.7

{μ mol}_{N_{2}}

s −1 g −1 ) and 7.1

{μ mol}_{{CO}_{2}}

s −1 g −1 for reduction and oxidation, respectively.…”

Section: Introductionmentioning

confidence: 99%

Solar Reactor Demonstration of Efficient and Selective Syngas Production via Chemical‐Looping Dry Reforming of Methane over Ceria

et al. 2020

View full text Add to dashboard Cite

show abstract

“…Fuel is produced continuously by alternating the gas flows between reactive elements. The design gas flow rates and cycling period are set to maximize reactor thermal efficiency and fuel productivity (Hathaway et al, 2015;Venstrom et al, 2014). The design flow rates are 0.67 Â 10 À 4 mol s À 1 g ceria À 1 of N 2 and CO 2 for a 200 s cycle equally split between reduction and oxidation.…”

Section: Reactormentioning

confidence: 99%

“…The reactor is well insulated to reduce thermal losses to the ambient. Based on operation of the reactor, thermal losses are anticipated to equal 35% of the absorbed solar energy (Hathaway et al, 2015).…”

Section: Reactormentioning

confidence: 99%

“…At the University of Minnesota, we have developed a 4 kW th solar reactor prototype with integrated gas phase heat recovery to implement the isothermal ceria redox cycle and have demonstrated continuous, production of CO from CO 2 (Hathaway et al, 2015). Prior publications present the supporting analyses for design and operation of the reactor (Bader et al, 2015;Hathaway et al, 2015;Venstrom et al, 2014) and the gas heat recovery system (Bala Chandran et al, 2015b;Banerjee et al, 2015).…”

Section: Introductionmentioning

confidence: 98%

“…Prior publications present the supporting analyses for design and operation of the reactor (Bader et al, 2015;Hathaway et al, 2015;Venstrom et al, 2014) and the gas heat recovery system (Bala Chandran et al, 2015b;Banerjee et al, 2015). In the present study, we present a transient, three-dimensional (3-D) numerical model of the reactor that couples heat and mass transport processes with the chemical reactions for splitting CO 2 .…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Model of transport and chemical kinetics in a solar thermochemical reactor to split carbon dioxide

Chandran

Davidson

2016

Chemical Engineering Science

Self Cite

View full text Add to dashboard Cite

A 3-D model of a solar reactor for the isothermal ceria redox cycle is presented. Reaction rate parameters are extracted for the redox reactions at 1773 K. Recovery of 90% of the sensible heat of the gases is achieved. For CO 2 splitting, CO is produced at 3.6×10 -4 mol s -1 for a 4.2 kW solar input. a b s t r a c t Solar thermochemical reactors to carry out the nonstoichiometric reduction and oxidation of cerium dioxide (ceria) to split water and carbon dioxide provide a pathway to store sunlight in a chemical fuel. One of the challenges in the design of these reactors is understanding the complex coupling of heat and mass transfer and redox chemistry. To elucidate this coupling, we present a three-dimensional, transient model of a recently developed prototype solar reactor that implements an isothermal, pressure-swing ceria redox cycle. Radiative transport is modeled by a hybrid Monte Carlo/finite volume approach and paired with the transport and chemical processes within a fixed bed of porous ceria particles. Morphology specific reaction rate coefficients for the gas-solid reactions in ceria are extracted for the first time from global rate measurements in a bench-top reactor at 1773 K. Results demonstrate the interdependent spatial and temporal variations in temperature, species concentration and reaction rates, and provide insight on the effects of optical properties on reactor performance. For a solar input of 4.2 kW, the reactor achieves nearly isothermal cycling at 1791 K with carbon monoxide produced continuously at 3.6 Â 10 À 4 mol s À 1 . At this temperature, global reaction rates are driven by advective mass transport rates and the intrinsic material thermodynamics. Predicted surface temperatures and fuel production rates compare favorably to measured data.

show abstract

Optimized operational strategy of a solar reactor for thermochemical hydrogen generation

Lampe,

Menz

2023

Optim Eng

View full text Add to dashboard Cite

Effect of Flow Rates on Operation of a Solar Thermochemical Reactor for Splitting CO2 Via the Isothermal Ceria Redox Cycle

Cited by 21 publications

References 21 publications

Solar Reactor Demonstration of Efficient and Selective Syngas Production via Chemical‐Looping Dry Reforming of Methane over Ceria

Solar Reactor Demonstration of Efficient and Selective Syngas Production via Chemical‐Looping Dry Reforming of Methane over Ceria

Model of transport and chemical kinetics in a solar thermochemical reactor to split carbon dioxide

Optimized operational strategy of a solar reactor for thermochemical hydrogen generation

Contact Info

Product

Resources

About