Chemical kinetics of two-step thermochemical decomposition of hydrogen sulfide over nickel sulfide

Asma Al Blooshi; Khalid Al-Ali; Ahmed AlHajaj; Giovanni Palmisano

doi:10.1016/j.ijhydene.2023.06.310

Chemical kinetics of two-step thermochemical decomposition of hydrogen sulfide over nickel sulfide

Asma Al Blooshi, Khalid Al-Ali, Ahmed AlHajaj, Giovanni Palmisano

Research output: Contribution to journal › Article › peer-review

3 Scopus citations

Abstract

The study develops a multistep reaction mechanism for a two-step thermochemical cycle that produces hydrogen from H₂S decomposition, using nickel sulfide as a catalyst. Two mechanisms were investigated: 1) a gas-phase mechanism that occurs without a Ni catalyst to determine the contribution of thermal decomposition to the overall reaction without a catalyst, and 2) a microkinetic model of the catalytic Ni surface phase to examine the key parameters affecting the overall cycling process and H₂S conversion efficiency. Both mechanisms were validated using CHEMKIN-Pro software to analyze the experimental data and trends. The study showed that gas-phase H₂S conversion was not kinetically significant below 850 °C. The microkinetic model showed that most H₂S was transformed into H₂ and NiS products when the sulfurization temperature reached 500 °C. Additionally, the site fraction of NiS decreased while the number of free active nickel sites increased as the regeneration temperature increased from 500 °C to 800 °C. A temperature limit of 700 °C was set for the regeneration step due to the agglomeration behavior of nickel sulfide particles.

Original language	British English
Pages (from-to)	433-446
Number of pages	14
Journal	International Journal of Hydrogen Energy
Volume	52
DOIs	https://doi.org/10.1016/j.ijhydene.2023.06.310
State	Published - 2 Jan 2024

Keywords

HS reaction mechanism
HS splitting
Hydrogen
Hydrogen sulfide
Nickel sulfide
Thermochemical cycle

UN SDGs

This output contributes to the following UN Sustainable Development Goals (SDGs)

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10.1016/j.ijhydene.2023.06.310

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title = "Chemical kinetics of two-step thermochemical decomposition of hydrogen sulfide over nickel sulfide",

abstract = "The study develops a multistep reaction mechanism for a two-step thermochemical cycle that produces hydrogen from H2S decomposition, using nickel sulfide as a catalyst. Two mechanisms were investigated: 1) a gas-phase mechanism that occurs without a Ni catalyst to determine the contribution of thermal decomposition to the overall reaction without a catalyst, and 2) a microkinetic model of the catalytic Ni surface phase to examine the key parameters affecting the overall cycling process and H2S conversion efficiency. Both mechanisms were validated using CHEMKIN-Pro software to analyze the experimental data and trends. The study showed that gas-phase H2S conversion was not kinetically significant below 850 °C. The microkinetic model showed that most H2S was transformed into H2 and NiS products when the sulfurization temperature reached 500 °C. Additionally, the site fraction of NiS decreased while the number of free active nickel sites increased as the regeneration temperature increased from 500 °C to 800 °C. A temperature limit of 700 °C was set for the regeneration step due to the agglomeration behavior of nickel sulfide particles.",

keywords = "HS reaction mechanism, HS splitting, Hydrogen, Hydrogen sulfide, Nickel sulfide, Thermochemical cycle",

author = "{Al Blooshi}, Asma and Khalid Al-Ali and Ahmed AlHajaj and Giovanni Palmisano",

note = "Publisher Copyright: {\textcopyright} 2023 Hydrogen Energy Publications LLC",

year = "2024",

month = jan,

day = "2",

doi = "10.1016/j.ijhydene.2023.06.310",

language = "British English",

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journal = "International Journal of Hydrogen Energy",

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TY - JOUR

T1 - Chemical kinetics of two-step thermochemical decomposition of hydrogen sulfide over nickel sulfide

AU - Al Blooshi, Asma

AU - Al-Ali, Khalid

AU - AlHajaj, Ahmed

AU - Palmisano, Giovanni

PY - 2024/1/2

Y1 - 2024/1/2

N2 - The study develops a multistep reaction mechanism for a two-step thermochemical cycle that produces hydrogen from H2S decomposition, using nickel sulfide as a catalyst. Two mechanisms were investigated: 1) a gas-phase mechanism that occurs without a Ni catalyst to determine the contribution of thermal decomposition to the overall reaction without a catalyst, and 2) a microkinetic model of the catalytic Ni surface phase to examine the key parameters affecting the overall cycling process and H2S conversion efficiency. Both mechanisms were validated using CHEMKIN-Pro software to analyze the experimental data and trends. The study showed that gas-phase H2S conversion was not kinetically significant below 850 °C. The microkinetic model showed that most H2S was transformed into H2 and NiS products when the sulfurization temperature reached 500 °C. Additionally, the site fraction of NiS decreased while the number of free active nickel sites increased as the regeneration temperature increased from 500 °C to 800 °C. A temperature limit of 700 °C was set for the regeneration step due to the agglomeration behavior of nickel sulfide particles.

AB - The study develops a multistep reaction mechanism for a two-step thermochemical cycle that produces hydrogen from H2S decomposition, using nickel sulfide as a catalyst. Two mechanisms were investigated: 1) a gas-phase mechanism that occurs without a Ni catalyst to determine the contribution of thermal decomposition to the overall reaction without a catalyst, and 2) a microkinetic model of the catalytic Ni surface phase to examine the key parameters affecting the overall cycling process and H2S conversion efficiency. Both mechanisms were validated using CHEMKIN-Pro software to analyze the experimental data and trends. The study showed that gas-phase H2S conversion was not kinetically significant below 850 °C. The microkinetic model showed that most H2S was transformed into H2 and NiS products when the sulfurization temperature reached 500 °C. Additionally, the site fraction of NiS decreased while the number of free active nickel sites increased as the regeneration temperature increased from 500 °C to 800 °C. A temperature limit of 700 °C was set for the regeneration step due to the agglomeration behavior of nickel sulfide particles.

KW - HS reaction mechanism

KW - HS splitting

KW - Hydrogen

KW - Hydrogen sulfide

KW - Nickel sulfide

KW - Thermochemical cycle

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U2 - 10.1016/j.ijhydene.2023.06.310

DO - 10.1016/j.ijhydene.2023.06.310

M3 - Article

AN - SCOPUS:85164664696

SN - 0360-3199

VL - 52

SP - 433

EP - 446

JO - International Journal of Hydrogen Energy

JF - International Journal of Hydrogen Energy

ER -

Chemical kinetics of two-step thermochemical decomposition of hydrogen sulfide over nickel sulfide

Abstract

Keywords

UN SDGs

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