Environmental and thermodynamic performance assessment of biomass gasification process for hydrogen production in a downdraft gasifier

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Tayebeh Marzoughi ◽  
Fereshteh Samimi ◽  
Mohammad Reza Rahimpour
Keyword(s):  
Hydrogen Production ◽  
Steam Gasification ◽  
Molar Ratio ◽  
Inlet Temperature ◽  
Hydrogen Yield ◽  
Comparative Performance ◽  
Gasification Process ◽  
Thermodynamic Performance ◽  
Biomass Materials ◽  
Gasification Temperature

Abstract Gasification is one of the most efficient techniques for sustainable hydrogen production from biomass. In this study, a comparative performance analysis of the gasification process using various types of biomass materials was undertaken via thermodynamic approach. Air, steam, and air/steam as the traditional gasifying agents were applied to provide an opportunity to choose the most proper agent in the process. This paper also evaluates the environmental impacts of the process in terms of CO2 emission by using Aspen Energy Analyzer. The effects of agent to biomass molar ratio, agent inlet temperature, moisture content of biomass material, and gasification temperature were estimated based on the producer gas compositions, hydrogen yield and heating values. The results indicate that the highest hydrogen yield (0.074 g H2/g biomass) was obtained in the steam gasification of plastic, while air gasification of paper generates the lowest one. It was also observed that manure is the most beneficial from environmental perspectives, while tire and plastic have the highest contribution to CO2 emission and consequently global warming. The higher values of hydrogen production and LHV of produced gas are associated respectively with using steam, air/steam, and air as the gasification agents. The lowest value of CO2 emission is obtained for air, air/steam, and steam as the gasifying agents, respectively.

Catalytic Steam Gasification of Glucose for Hydrogen Production Using Stable Based Ni on a γ–Alumina Fluidizable Catalyst

2019 ◽  
Vol 17 (11) ◽  
Author(s):  
Daniel Gibran González Castañeda ◽  
Adriana Sanchez Enríquez ◽  
Ivan Cruz Reyes ◽  
Alan Ruben Calzada Hernández ◽  
Benito Serrano Rosales
Keyword(s):  
Hydrogen Production ◽  
Close Agreement ◽  
Steam Gasification ◽  
The Other ◽  
Hydrogen Yield ◽  
Acid Solutions ◽  
Metal Dispersion ◽  
Catalytic Gasification ◽  
Oxygen Conditions ◽  
Hydrogen Pretreatment

Abstract Six different Ni-based fluidizable catalysts were synthesized using both incipient impregnation and co-impregnation. Ni-based catalysts were also promoted with 2.0 wt% La or alternatively with 2 wt% Ce. The preparation procedure included catalysts treated at high temperatures and under free of oxygen conditions. Catalysts were characterized using BET, XRD, AA, PSD, TPR, TPD, H2-chemisorption. TPR and H2 chemisorption showed good metal dispersion with 10 nm- 40 nm metal crystallites. Glucose catalytic gasification runs were performed in a CREC Riser Simulator to evaluate the following catalysts: (a) 5 %Ni/γ-Al2O3, (b) 5 %Ni-2 %La/γ-Al2O3 and (c) 5 %Ni-2 %Ce/γ-Al2O3. In all cases, the preparation steps involved acid solutions with pHs of 1 and 4. In between consecutive runs, different approaches were considered: (a) A catalyst was regenerated by air, (b) A catalyst was regenerated by air followed by hydrogen pretreatment, (c) A catalyst was reused directly without any regeneration or hydrogen pretreatment. It was observed that Ni-based catalysts, which were subjected after every run, to both, air regeneration and hydrogen pretreatment, displayed the best yields in close agreement with thermodynamic equilibrium. On the other hand, Ni-based catalysts regenerated with air only, showed the worst hydrogen yields. In between these two-hydrogen yield limits, where catalysts not contacted with air nor hydrogen, with these yields being moderately below chemical equilibrium. This shows that Ni-based fluidizable catalysts can perform on stream for extended periods, requiring limited reactivation with air and H2. This makes of gasification using the catalysts of the present study, a viable process alternative that could be implemented at industrial scale.

Pyrolysis and Steam Gasification of Paper and Evaluation of Paper Char Kinetics

2009 ◽  
Author(s):  
Islam Ahmed ◽  
Ashwani K. Gupta
Keyword(s):  
Flow Rate ◽  
Steam Gasification ◽  
Energy Yield ◽  
Hydrogen Yield ◽  
Hydrogen Flow Rate ◽  
Hydrogen Flow ◽  
Char Gasification ◽  
Gasification Process ◽  
Reactor Temperature ◽  
Partial Overlap

Main characteristics of gaseous yield from steam gasification have been investigated experimentally. Results of steam gasification have been compared to that of pyrolysis. The temperature range investigated were 600 to 1000°C in steps of 100°C. Results have also been obtained under pyrolysis conditions at same temperatures. For steam gasification runs, steam flow rate was kept constant at 8.0 gr./Min.. Investigated characteristics were evolution of syngas flow rate with time, hydrogen flow rate, chemical composition of syngas, energy yield and apparent thermal efficiency. Residuals from both processes were quantified and compared as well. Material destruction, hydrogen yield and energy yield is better with gasification as compared to pyrolysis. This advantage of the gasification process is attributed mainly to char gasification process. Char gasification is found to be more sensitive to the reactor temperature than pyrolysis. Pyrolysis can start at low temperatures of 400 °C; however char gasification starts at 700 °C. A partial overlap between gasification and pyrolysis exists and is presented here. This partial overlap increases with increase in temperature. As an example, at reactor temperature 800 °C this overlap represents around 27% of the char gasification process and almost 95% at reactor temperature 1000°C.

Hydrogen Production from Ethanol Steam Reforming over Ni-Cu/ZnO Catalyst

2011 ◽  
Vol 236-238 ◽  
pp. 1067-1072
Author(s):  
Li Ping Liu ◽  
Xiao Jian Ma ◽  
Peng Zhang ◽  
Ya Nan Liu
Keyword(s):  
Hydrogen Production ◽  
Steam Reforming ◽  
Fixed Bed ◽  
Surface Characteristics ◽  
Catalytic Performance ◽  
Fixed Bed Reactor ◽  
Molar Ratio ◽  
Ethanol Steam Reforming ◽  
Hydrogen Yield ◽  
Ethanol Steam

Hydrogen production by ethanol steam reforming over Ni-Cu/ZnO catalyst in the temperatures range of 250-550°C was studied on a fixed bed reactor. The effects of reaction temperature and water/ethanol molar ratio on hydrogen production were investigated. The structure and surface characteristics of the catalyst were measured by scanning electron microscopy (SEM), X-ray diffraction (XRD) and differential thermal analyzer (TG-DSC). The results show that the Ni-Cu/ZnO catalyst has good catalytic performance with higher hydrogen yield of 4.87molH2/molEtOH reacted. A comparison of hydrogen production from ethanol steam reforming over Ni-Cu/ZnO catalyst with over a commercial catalyst was made in this paper.

Simulation of Hydrogen Production by Using Concentrated Solar Energy Through Thermo-Chemical Water Splitting Process: Part II—Simulation of Zinc Hydrolysis Reaction to Generate Hydrogen

2011 ◽  
Author(s):  
Furqan Ahmad Khan ◽  
Kamran Siddiqui
Keyword(s):  
Hydrogen Production ◽  
Wall Temperature ◽  
Particle Diameter ◽  
Molar Ratio ◽  
Reactor Wall ◽  
Hydrogen Yield ◽  
Concentrated Solar Energy ◽  
Cylindrical Reactor ◽  
Chemical Cycle ◽  
Zinc Particle

This study is focused on the second step of ZnO/Zn thermo-chemical cycle, where zinc (produced in the first step of the cycle) reacts with steam to produce hydrogen and zinc oxide. The simulation of this hydrogen production step was carried out inside a cylindrical reactor using commercial CFD software, FLUENT. A parametric study was conducted based on the zinc particle diameter, reactor wall temperature, and steam/zinc molar ratio. The yield of hydrogen was found to increase with an increase in the reactor wall temperature, and with a decrease in the zinc particle diameter. However, steam/zinc molar ratio was found to have no effect on the hydrogen yield.

scholarly journals Hydrogen Production by Partial Oxidation Reforming of Methane over Ni Catalysts Supported on High and Low Surface Area Alumina and Zirconia

Processes ◽  
2020 ◽  
Vol 8 (5) ◽  
pp. 499 ◽  
Author(s):  
Anis Fakeeha ◽  
Ahmed A. Ibrahim ◽  
Hesham Aljuraywi ◽  
Yazeed Alqahtani ◽  
Ahmad Alkhodair ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Hydrogen Production ◽  
Surface Area ◽  
Partial Oxidation ◽  
Reaction Temperature ◽  
Molar Ratio ◽  
Hydrogen Yield ◽  
Impregnation Method ◽  
H2 Yield ◽  
Partial Oxidation Reforming

The catalytic activity of the partial oxidation reforming reaction for hydrogen production over 10% Ni supported on high and low surface area alumina and zirconia was investigated. The reforming reactions, under atmospheric pressure, were performed with a feed molar ratio of CH4/O2 = 2.0. The reaction temperature was set to 450–650 °C. The catalytic activity, stability, and carbon formation were determined via TGA, TPO, Raman, and H2 yield. The catalysts were calcined at 600 and 800 °C. The catalysts were prepared via the wet-impregnation method. Various characterizations were conducted using BET, XRD, TPR, TGA, TPD, TPO, and Raman. The highest methane conversion (90%) and hydrogen yield (72%) were obtained at a 650 °C reaction temperature using Ni-Al-H-600, which also showed the highest stability for the ranges of the reaction temperatures investigated. Indeed, the time-on-stream for 7 h of the Ni-Al-H-600 catalyst displayed high activity and a stable profile when the reaction temperature was set to 650 °C.

Thermodynamic Analysis of Hydrogen Production from Ethanol in Supercritical Water Oxidation

2011 ◽  
Vol 110-116 ◽  
pp. 77-82
Author(s):  
Nawadee Srisiriwat
Keyword(s):  
Carbon Dioxide ◽  
Carbon Monoxide ◽  
Hydrogen Production ◽  
Thermodynamic Analysis ◽  
Supercritical Water ◽  
Water Oxidation ◽  
Equilibrium Composition ◽  
Operating Conditions ◽  
Molar Ratio ◽  
Hydrogen Yield

A thermodynamic analysis was performed for hydrogen production from ethanol reforming and oxidation in supercritical water (SCW) conditions. The minimization of Gibbs free energy was used to calculate the equilibrium composition to investigate the effect of operating conditions, pressure, temperature, H2O2:EtOH molar ratio and H2O:EtOH molar ratio, on product yields. The theoretical results indicated that the yields of hydrogen and carbon monoxide decreased as the pressure increased but a H2/CO ratio at atmospheric pressure was lower than that at SCW conditions. High temperatures increased the efficiency of hydrogen production although the amount of carbon monoxide also increased. The presence of oxygen led to great decreases in methane oxidized to carbon dioxide and water. The spending of some hydrogen oxidized to water resulting in a lower hydrogen yield. High H2O:EtOH ratios increased the yields of hydrogen and carbon dioxide but decreased the methane and carbon monoxide production. It is possible to conclude that high temperature, high H2O:EtOH ratio and low addition of oxygen should lead to best results in the SCWO of ethanol.

Hydrogen production by steam reforming of glycerol over Ni/Ce/Cu hydroxyapatite-supported catalysts

2013 ◽  
Vol 67 (7) ◽  
Author(s):  
Lukman Hakim ◽  
Zahira Yaakob ◽  
Manal Ismail ◽  
Wan Daud ◽  
Ratna Sari
Keyword(s):  
Hydrogen Production ◽  
Steam Reforming ◽  
Fixed Bed ◽  
Supported Catalyst ◽  
Fixed Bed Reactor ◽  
Bet Surface Area ◽  
Precipitation Method ◽  
Molar Ratio ◽  
Hydrogen Yield ◽  
Glycerol Conversion

AbstractHydroxyapatite-supported Ni-Ce-Cu catalysts were synthesised and tested to study their potential for use in the steam reforming of glycerol to produce hydrogen. The catalysts were prepared by the deposition-precipitation method with variable nickel, cerium, and copper loadings. The performance of the catalysts was evaluated in terms of hydrogen yield at 600°C in a tubular fixed-bed microreactor. All catalysts were characterised by the BET surface area, XRD, TPR, TEM, and FE-SEM techniques. The reaction time was 240 min in a fixed-bed reactor at 600°C and atmospheric pressure with a water-to-glycerol feed molar ratio of 8: 1. It was found that the Ni-Ce-Cu (3 mass %-7.5 mass %-7.5 mass %) hydroxyapatite-supported catalyst afforded the highest hydrogen yield (57.5 %), with a glycerol conversion rate of 97.3 %. The results indicate that Ni/Ce/Cu/hydroxyapatite has great potential as a catalyst for hydrogen production by steam reforming of glycerol.

scholarly journals Thermodynamic Analysis of the Hydrogen Production from Ethanol: First and Second Laws Approaches

2012 ◽  
Vol 2012 ◽  
pp. 1-8 ◽  
Author(s):  
Yannay Casas-Ledón ◽  
Luis E. Arteaga-Perez ◽  
Mayra C. Morales-Perez ◽  
Luis M. Peralta-Suárez
Keyword(s):  
Hydrogen Production ◽  
Thermodynamic Analysis ◽  
Direct Method ◽  
Positive Influence ◽  
State Equation ◽  
Molar Ratio ◽  
Ethanol Conversion ◽  
Hydrogen Yield ◽  
System Quality ◽  
Ethanol Steam

A thermodynamic analysis of hydrogen production from ethanol steam reforming (ESR) is carried out in the present paper. The influence of reactants molar ratio feed into the reforming stage (), temperature (573 to 1173 K) and pressure ( atm) over equilibrium compositions is studied. The direct method employed to analyze the system is the minimization of Gibbs free energy (MGFE) in conjunction with Lee-Kesler state equation, using the Kay mixing rules. The temperature and reactants molar ratio showed a positive influence on the hydrogen yield; ethanol conversion is 100% for the whole interval analyzed while the pressure affected greatly the hydrogen production. The carbon deposition exhibits a maximum value at temperatures around 773 K, and three reactions are proposed to describe the solid carbon formation in a wide temperature range based on thermodynamics and experimental predictions. The conditioning stages (mixing, vaporization, and heating) are studied in addition to the reaction to analyze the system quality by means of an exergetic method applying the 2nd law of thermodynamic.

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