Interplay of Kinetics and Thermodynamics in Catalytic Steam Methane Reforming over Ni/MgO-SiO2

Naoki Kageyama, Brigitte R. Devocht, Atsushi Takagaki, Kenneth Toch, Joris W. Thybaut, Guy B. Marin, S. Ted Oyama

Research output: Contribution to journalArticle

4 Citations (Scopus)

Abstract

The steam methane reforming (SMR) reaction was studied on a Ni/MgO-SiO2 catalyst at 923 K (650°C) and 0.40 MPa in a tubular packed-bed reactor. The partial pressures of CH4 and H2O were varied between 20 and 140 kPa and 80 and 320 kPa, respectively. Measurements were carried out without mass and heat transport limitations, as verified by the Weisz-Prater and Mears criteria. Experimentally, the CH4 conversion increased with the inlet partial pressure of H2O and decreased with the inlet partial pressure of CH4. However, at low CH4 inlet partial pressures, i.e., at 40 and 60 kPa, the conversion passed through a maximum. Rate expressions were derived based on a simple two-step sequence. A statistical analysis led to a globally significant, weighted regression and resulted in a good agreement between the model and the experimental data, as indicated by a low F value of model adequacy of 2.84. The rate and equilibrium coefficient parameters were statistically significant as indicated by narrow confidence intervals. The model was able to correctly describe the experimentally observed maximum in the methane conversion and allowed relating this behavior to CH4 and H2O surface coverages. The model was able to capture the increasing selectivity to CO2 with increasing H2O inlet partial pressure and methane conversion. The effect of changing the total pressure and H2O/CH4 ratio on the CH4 conversion as a function of the space velocity was simulated and corresponded to both the experimental and literature data. A major finding of the modeling was that as flow rate was increased there was a crossover in the order of conversion with pressure due to a transition from thermodynamic to kinetic control. Although the SMR equilibrium conversion decreased with pressure, away from equilibrium at high flow rates, conversion was higher at higher pressures because of enhanced adsorption rates. (Graph Presented).

Original languageEnglish
Pages (from-to)1148-1158
Number of pages11
JournalIndustrial and Engineering Chemistry Research
Volume56
Issue number5
DOIs
Publication statusPublished - Feb 8 2017
Externally publishedYes

Fingerprint

Steam reforming
Partial pressure
Thermodynamics
Kinetics
Methane
Flow rate
Packed beds
Reforming reactions
Statistical methods
Adsorption
Catalysts

All Science Journal Classification (ASJC) codes

  • Chemistry(all)
  • Chemical Engineering(all)
  • Industrial and Manufacturing Engineering

Cite this

Interplay of Kinetics and Thermodynamics in Catalytic Steam Methane Reforming over Ni/MgO-SiO2 . / Kageyama, Naoki; Devocht, Brigitte R.; Takagaki, Atsushi; Toch, Kenneth; Thybaut, Joris W.; Marin, Guy B.; Oyama, S. Ted.

In: Industrial and Engineering Chemistry Research, Vol. 56, No. 5, 08.02.2017, p. 1148-1158.

Research output: Contribution to journalArticle

Kageyama, Naoki ; Devocht, Brigitte R. ; Takagaki, Atsushi ; Toch, Kenneth ; Thybaut, Joris W. ; Marin, Guy B. ; Oyama, S. Ted. / Interplay of Kinetics and Thermodynamics in Catalytic Steam Methane Reforming over Ni/MgO-SiO2 In: Industrial and Engineering Chemistry Research. 2017 ; Vol. 56, No. 5. pp. 1148-1158.
@article{f0267b071aba476bae7f74ebcddf1b70,
title = "Interplay of Kinetics and Thermodynamics in Catalytic Steam Methane Reforming over Ni/MgO-SiO2",
abstract = "The steam methane reforming (SMR) reaction was studied on a Ni/MgO-SiO2 catalyst at 923 K (650°C) and 0.40 MPa in a tubular packed-bed reactor. The partial pressures of CH4 and H2O were varied between 20 and 140 kPa and 80 and 320 kPa, respectively. Measurements were carried out without mass and heat transport limitations, as verified by the Weisz-Prater and Mears criteria. Experimentally, the CH4 conversion increased with the inlet partial pressure of H2O and decreased with the inlet partial pressure of CH4. However, at low CH4 inlet partial pressures, i.e., at 40 and 60 kPa, the conversion passed through a maximum. Rate expressions were derived based on a simple two-step sequence. A statistical analysis led to a globally significant, weighted regression and resulted in a good agreement between the model and the experimental data, as indicated by a low F value of model adequacy of 2.84. The rate and equilibrium coefficient parameters were statistically significant as indicated by narrow confidence intervals. The model was able to correctly describe the experimentally observed maximum in the methane conversion and allowed relating this behavior to CH4 and H2O surface coverages. The model was able to capture the increasing selectivity to CO2 with increasing H2O inlet partial pressure and methane conversion. The effect of changing the total pressure and H2O/CH4 ratio on the CH4 conversion as a function of the space velocity was simulated and corresponded to both the experimental and literature data. A major finding of the modeling was that as flow rate was increased there was a crossover in the order of conversion with pressure due to a transition from thermodynamic to kinetic control. Although the SMR equilibrium conversion decreased with pressure, away from equilibrium at high flow rates, conversion was higher at higher pressures because of enhanced adsorption rates. (Graph Presented).",
author = "Naoki Kageyama and Devocht, {Brigitte R.} and Atsushi Takagaki and Kenneth Toch and Thybaut, {Joris W.} and Marin, {Guy B.} and Oyama, {S. Ted}",
year = "2017",
month = "2",
day = "8",
doi = "10.1021/acs.iecr.6b03614",
language = "English",
volume = "56",
pages = "1148--1158",
journal = "Industrial & Engineering Chemistry Research",
issn = "0888-5885",
publisher = "American Chemical Society",
number = "5",

}

TY - JOUR

T1 - Interplay of Kinetics and Thermodynamics in Catalytic Steam Methane Reforming over Ni/MgO-SiO2

AU - Kageyama, Naoki

AU - Devocht, Brigitte R.

AU - Takagaki, Atsushi

AU - Toch, Kenneth

AU - Thybaut, Joris W.

AU - Marin, Guy B.

AU - Oyama, S. Ted

PY - 2017/2/8

Y1 - 2017/2/8

N2 - The steam methane reforming (SMR) reaction was studied on a Ni/MgO-SiO2 catalyst at 923 K (650°C) and 0.40 MPa in a tubular packed-bed reactor. The partial pressures of CH4 and H2O were varied between 20 and 140 kPa and 80 and 320 kPa, respectively. Measurements were carried out without mass and heat transport limitations, as verified by the Weisz-Prater and Mears criteria. Experimentally, the CH4 conversion increased with the inlet partial pressure of H2O and decreased with the inlet partial pressure of CH4. However, at low CH4 inlet partial pressures, i.e., at 40 and 60 kPa, the conversion passed through a maximum. Rate expressions were derived based on a simple two-step sequence. A statistical analysis led to a globally significant, weighted regression and resulted in a good agreement between the model and the experimental data, as indicated by a low F value of model adequacy of 2.84. The rate and equilibrium coefficient parameters were statistically significant as indicated by narrow confidence intervals. The model was able to correctly describe the experimentally observed maximum in the methane conversion and allowed relating this behavior to CH4 and H2O surface coverages. The model was able to capture the increasing selectivity to CO2 with increasing H2O inlet partial pressure and methane conversion. The effect of changing the total pressure and H2O/CH4 ratio on the CH4 conversion as a function of the space velocity was simulated and corresponded to both the experimental and literature data. A major finding of the modeling was that as flow rate was increased there was a crossover in the order of conversion with pressure due to a transition from thermodynamic to kinetic control. Although the SMR equilibrium conversion decreased with pressure, away from equilibrium at high flow rates, conversion was higher at higher pressures because of enhanced adsorption rates. (Graph Presented).

AB - The steam methane reforming (SMR) reaction was studied on a Ni/MgO-SiO2 catalyst at 923 K (650°C) and 0.40 MPa in a tubular packed-bed reactor. The partial pressures of CH4 and H2O were varied between 20 and 140 kPa and 80 and 320 kPa, respectively. Measurements were carried out without mass and heat transport limitations, as verified by the Weisz-Prater and Mears criteria. Experimentally, the CH4 conversion increased with the inlet partial pressure of H2O and decreased with the inlet partial pressure of CH4. However, at low CH4 inlet partial pressures, i.e., at 40 and 60 kPa, the conversion passed through a maximum. Rate expressions were derived based on a simple two-step sequence. A statistical analysis led to a globally significant, weighted regression and resulted in a good agreement between the model and the experimental data, as indicated by a low F value of model adequacy of 2.84. The rate and equilibrium coefficient parameters were statistically significant as indicated by narrow confidence intervals. The model was able to correctly describe the experimentally observed maximum in the methane conversion and allowed relating this behavior to CH4 and H2O surface coverages. The model was able to capture the increasing selectivity to CO2 with increasing H2O inlet partial pressure and methane conversion. The effect of changing the total pressure and H2O/CH4 ratio on the CH4 conversion as a function of the space velocity was simulated and corresponded to both the experimental and literature data. A major finding of the modeling was that as flow rate was increased there was a crossover in the order of conversion with pressure due to a transition from thermodynamic to kinetic control. Although the SMR equilibrium conversion decreased with pressure, away from equilibrium at high flow rates, conversion was higher at higher pressures because of enhanced adsorption rates. (Graph Presented).

UR - http://www.scopus.com/inward/record.url?scp=85013140423&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=85013140423&partnerID=8YFLogxK

U2 - 10.1021/acs.iecr.6b03614

DO - 10.1021/acs.iecr.6b03614

M3 - Article

AN - SCOPUS:85013140423

VL - 56

SP - 1148

EP - 1158

JO - Industrial & Engineering Chemistry Research

JF - Industrial & Engineering Chemistry Research

SN - 0888-5885

IS - 5

ER -