Steam Reforming Of Bioethanol Research Articles

Enhancing Bio-Ethanol conversion to renewable H2 via Ethanol Steam Reforming over a highly porous “one-pot” nickel and molybdenum carbide-based catalyst

The pursuit of an economical, active, and stable catalyst for Bio-Ethanol Steam Reforming (ESR) to facilitate renewable H2 production continues. Especially considering that traditional-noble-metal-based catalysts, are too expensive for large scale applications. In this paper, a sol-gel Ni–Mo2C–Al2O3 catalyst was employed for the first time in the ESR reaction. Synthesized by an innovative “one-pot” sol-gel method, this highly porous catalyst (670 m2. gcat−1) promises to deliver, in a single material, the nickel's ability on cleaving C–C bonds with the known catalytic stability of Mo2C in reforming reactions. Catalytic stability and activity were tested over a wide range of temperatures (450 °C-700 °C) and at a high Gas-Hourly-Space-Velocity (GHSV), 200,000 mmol h−1. gcat−1. The high temperature tests (T > 650 °C) exhibited elevated stability (over 12 h) and activity (ethanol conversion and H2-Production-Rate of 100 % and 1700 mmol h−1. gcat−1, respectively). Besides, TPO-O2 and TEM micrographs have shown the presence of both graphitic and aromatic coke on tests E and H spent catalysts, 2.08 mgcarbon. gcat− 1h−1 and 541 mgcarbon. gcat− 1h−1, respectively. Nevertheless, given its more graphitic nature and lower formation rate, H2 yield, and conversion remained constant throughout the entirety of the high-temperature tests, confirming that the coke did not block the catalytic sites.

Development of Ni Nanoparticle Encapsulated with Silicalite-1 Catalyst for High Activity Steam Reforming of Bioethanol with High Sintering Resistance and Coke Suppression

Development of Ni Nanoparticle Encapsulated with Silicalite-1 Catalyst for High Activity Steam Reforming of Bioethanol with High Sintering Resistance and Coke Suppression

Modulating Mxene‐Derived Ni‐Mom‐Mo2‐mTiC2Tx Structure for Intensified Low‐Temperature Ethanol Reforming

AbstractThe technology of steam reforming of bioethanol has drawn great attention to green hydrogen production. However, catalyst deactivation has always been a significant obstacle to its applications. Here, a series of yNi/Mo2TiC2Tx (yNi/MTC) materials are tailored as robust catalysts for highly efficient long‐term ethanol reforming. The results reveal that hydrogen utilization efficiency of up to 95.6% and almost total ethanol conversion can be achieved at 550 °C using a 10Ni/MTC‐72h catalyst. Moreover, this catalyst has remarkable stability without obvious deactivation after 100 h of bioethanol reforming, which can be attributed to the formation of a Ni─Mo alloy and the strong interaction of the Ni‐Mom‐Mo2‐mTiC2Tx structure. The FTIR‐MS studies demonstrate the superiority of the 10Ni/MTC‐72h catalyst for reinforcing low‐temperature bioethanol activation, as verified by the faster conversion of acetate species than with Ni/Al2O3. The adsorption energies of ethanol on the surface of Ni (−1.07 eV) and Ni/MTC (−1.46 eV) are compared by density functional theory calculations and show the superiority of the Ni/MTC catalyst for activating ethanol during steam reforming. This study provides new implications for highly stabilized Ni‐Mom‐Mo2‐mTiC2Tx construction, which is expected to substantially promote the development and application of bioethanol‐to‐hydrogen production technologies.

Recent advances and prospects in high purity H2 production from sorption enhanced reforming of bio-ethanol and bio-glycerol as carbon negative processes: A review

Hydrogen has wide applications in the chemical and petroleum industries and is a clean energy carrier for electrical power generation and transportation. However, in current industries, H2 is mainly obtained from the steam reforming of natural gas and coal gasification, which resulted in huge emissions of CO2 (greenhouse gasses) and high energy consumption for H2 purification. Hence, developing H2 production technology in sustainable routes with low carbon emissions is still urgent. Sorption-enhanced steam reforming of bio-ethanol (SESRE) and sorption-enhanced steam reforming of bio-glycerol (SESRG), which coupled in-situ CO2 capture with the steam reforming of bio-ethanol or bio-glycerol, are promising strategies to yield high purity of H2 without emitting CO2 into the atmosphere. In these strategies, high purity of H2 can be produced when the high energy-consumption process such as H2 purification is avoided; besides, negative CO2 emissions can be achieved when the captured CO2 is used or sequestered. The catalysts play a pivotal role in the steam reforming processes, and the dual-functional materials (DFMs) are well regarded as the most promising solid catalysts that contribute to high-purity H2 production and CO2 capture. Thus far, there is no criterion to guide DFMs engineering for H2 generation in the SESRE and SESRG processes. Hence, in this work, a comprehensive review of the recent advances and prospects in SESRE and SESRG is presented, which provides constructive insight into the development of SESRE and SESRG technology. The optimum operating conditions in the SESRE and SESRG systems are analyzed via thermodynamics and kinetics, and the recent research progress of the DFMs is critically reviewed. Furthermore, the reforming reaction pathways and reaction mechanisms were discussed to improve the understanding of DFMs design. Finally, the prospect and challenges in the SESRE and SESRG strategies are outlooked.

Rice Husk Ash-Derived Ca-Mg-Modified Silicate as Support for Ni-Co for Hydrogen Production by Sorption-Enhanced Steam Reforming of Bioethanol

A multipurpose catalyst made of nickel and cobalt supported on silicate-based material modified by Ca and Mg was developed and used in sorption-enhanced steam reforming of (bio)-ethanol (SESRE). In SESRE, steam reforming and CO2 conversion to carbonates occur together to yield clean hydrogen. The catalyst was designed using silica sourced from rice hull ash (RHA) by oxidation and, subsequently, Ni and Co were loaded by the wet-impregnation technique. Three catalysts, namely, Ni/Ca-Mg silicate, Co/Ca-Mg silicate, and Ni-Co/Ca-Mg silicate, were synthesized with different metal loadings (5–15% w/w), among which 10 %Ni-10% Co/Ca-Mg silicate was the most active and selective. Various characterization techniques were used to determine the physico-chemical properties of 10% NI-10% Co/Ca-Mg silicate. CO2-sorption capacity and adsorption breakthrough time were measured. An adsorption capacity of 7.4 mol CO2/kg sorbent and a breakthrough time of 58 min at T = 723 K were observed with hydrogen production at 88 mol %. The catalyst was evaluated and optimized using such parameters as temperature, S/C ratio, and space velocity. The catalyst was tested for its robustness and found to be stable for 10 cycles. 10% Ni-10% Co/Ca-Mg yielded the best hydrogen output under the optimized operating conditions.

CO2 utilization for the production of liquid hydrocarbons by coupled steam and dry reforming of bioethanol

ABSTRACT Ethanol is an interesting fuel that can be produced by both renewable and nonrenewable resources and can be used as fuel or additive to fuels. But bioethanol is not equivalent one by one by fossil fuels in vehicles. In this study, the production of liquid hydrocarbons as synthetic fuels using bioethanol reforming has been simulated by Aspen HYSYS. For this purpose, two processes for syngas production have been proposed: 1: bioethanol steam reforming (ESR) and 2: bioethanol steam reforming coupled with dry reforming (ESR+EDR). Effective parameters including temperature, steam-to-carbon ratio, residence time, and feed split ratio have been evaluated. It is shown that the value of H2/CO using the syngas produced from ESR is in the range of 5. This ratio was modified using ESR+EDR without and with CO2 injection by 2.5 and 2, respectively. These values are suitable for the production of liquid hydrocarbons in the gasoline range. The C5 + selectivity using synthesis gas produced in the Fischer-Tropsch reactor in the ESR and the ESR+EDR without and with CO2 injection has been obtained by is 17.21%, 40.43%, and 42.96%, while CO2 selectivity has been emitted by 0.11, 0.53, and 0.71.

Steam Reforming of Bioethanol Using Metallic Catalysts on Zeolitic Supports: An Overview

Hydrogen is considered one of the energy carriers of the future due to its high mass-based calorific value. Hydrogen combustion generates only water, and it can be used directly as a fuel for electricity/heat generation. Nowadays, about 95% of the hydrogen is produced via conversion of fossil fuels. One of the future challenges is to find processes based on a renewable source to produce hydrogen in a sustainable way. Bioethanol is a promising candidate, since it can be obtained from the fermentation of biomasses, and easily converted into hydrogen via steam catalytic reforming. The correct design of catalysts and catalytic supports plays a crucial role in the optimization of this reaction. The best results have to date been achieved by noble metals, but their high costs make them unsuitable for industrial application. Very satisfactory results have also been achieved by using nickel and cobalt as active metals. Furthermore, it has been found that the support physical and chemical properties strongly affect the catalytic performance. In this review, zeolitic materials used for the ethanol steam reforming reaction are overviewed. We discuss thermodynamics, reaction mechanisms and the role of active metal, as well as the main noble and non-noble active compounds involved in ethanol steam reforming reaction. Finally, an overview of the zeolitic supports reported in the literature that can be profitably used to produce hydrogen through ethanol steam reforming is presented.

Regulation of Oxygen Activity by Lattice Confinement over Ni Mg1−O Catalysts for Renewable Hydrogen Production

The chemical looping steam reforming (CLSR) of bioethanol is an energy-efficient and carbon-neutral approach of hydrogen production. This paper describes the use of a Ni x Mg 1− x O solid solution as the oxygen carrier (OC) in the CLSR of bioethanol. Due to the regulation effect of Mg 2+ in Ni x Mg 1− x O, a three-stage reaction mechanism of the CLSR process is proposed. The surface oxygen of Ni x Mg 1− x O initially causes complete oxidation of the ethanol. Subsequently, H 2 O and bulk oxygen confined by Mg 2+ react with ethanol to form CH 3 COO* followed by H 2 over partially reduced Ni x Mg 1− x O. Once the bulk oxygen is consumed, the ethanol steam reforming process is promoted by the metallic nickel in the stage III. As a result, Ni 0.4 Mg 0.6 O exhibits a high H 2 selectivity (4.72 mol H 2 per mole ethanol) with a low steam-to-carbon molar ratio of 1, and remains stable over 30 CLSR cycles. The design of this solid-solution OC provides a versatile strategy for manipulating the chemical looping process.

Stability of bimetallic Ni/CeO2–SiO2 catalysts during fuel grade bioethanol reforming in a fluidized bed reactor

Oxidative steam reforming of bioethanol has been investigated in a fluidized bed reactor under atmospheric pressure at 500 °C over Pt–Ni/CeO2–SiO2 and Ru–Ni/CeO2–SiO2 catalysts, prepared with a noble metal content in the range 0–3 wt%. A preliminary investigation of the bimetallic catalysts performance was performed under a simulated bioethanol/oxygen stream (C2H5OH:H2O:O2:Ar = 10:40:5:45) at 500 °C and WHSV = 61.7 h−1. Poor stability was recorded over the low-loaded samples of both the series and the highest ethanol conversion as well as H2 yield after 25 h of time-on-stream were recorded over the 2 Pt–10Ni/CeO2–SiO2 catalyst. In fact, a growth in the content of the noble metal assured an improvement in terms of resistance towards deactivation. However, a further increase up to 2 wt% was detrimental for both Pt and Rh-based catalysts. The most durable catalyst (2 Pt–10Ni) was additionally tested under a raw bioethanol stream (commercial fuel grade bioethanol) for 100 h at 4.1 h−1: complete conversion and a stable H2 yield above 50% was obtained; the characterization of the spent catalyst mainly revealed the formation of filamentous coke, which is expected to cause a low extent of deactivation. As a result, no apparent activity loss was observed and the bimetallic catalyst appeared a promising candidate for reforming of crude ethanol.

Hydrogen production from the steam reforming of bioethanol over novel supported Ca/Ni-hierarchical Beta zeolite catalysts

This paper studies the H2 production via the steam reforming of a bioresource-derived ethanol mixture over supported Ca-modified Ni-hierarchical Beta zeolite catalysts. The results showed that the hierarchical Beta zeolite with rich pore structure could be synthesized in one step by using the new quaternary ammonium gemini cationic surfactant. The zeolite had bigger BET area and pore volume than the traditional Beta zeolite. The support plays a key role for the improve of catalytic behavior. The internal structure of the catalyst can be changed by introducing calcium and nickel ions into the synthesized zeolite at the same time through ion exchange. The interaction between active metal and the support would increase, so the dispersion of the active metal can be improved. The intermediate CO2 was efficiently absorbed by Ca in situ, which is an exothermic reaction and also help to provide the heat for the reactor. The adsorption of СО2 in situ transmitting the reversible reforming and water gas shift reactions to the products outside their conventional thermodynamic restrictions, which enhanced H2 production and permits high conversion to be attained. By using the method of gradient distribution of active metal in the support, the repeated catalytic effect similar to that of a hierarchical reactor was constructed, which showed excellent catalytic effect in low and medium high temperature bioethanol reforming to hydrogen. The experimental results show that when the reaction temperature is 350 °C, the 10Ni-MBeta(DI) catalyst maintains stable catalytic efficiency for continuous hydrogen production of 50 h via ESR, high hydrogen production and good stability.

Tunable metal-oxide interaction with balanced Ni0/Ni2+ sites of NixMg1−xO for ethanol steam reforming

Steam reforming of bio-ethanol is one of the most promising methods to produce renewable hydrogen and reduce carbon footprint. Nickel and magnesium are two main elements in commercial steam reforming catalysts for which NixMg1−xO solid solution contributes its unique property. This paper describes the interplay between Ni and NixMg1−xO to explore the roles of Ni0 and Ni2+ in hydrogen production from bio-ethanol steam reforming. With a non-equilibrium synthetic method, the ratio of metallic Ni0 to Ni2+ in Ni/NixMg1−xO system could be altered with same Ni loading. The catalytic performance of Ni/NixMg1−xO is dependent on the surface area of metallic Ni0 and the surface concentration of Ni2+ sites. Ni/NixMg1−xO with balanced Ni0 to Ni2+ sites could achieve H2 production rate of 11.5 L∙h−1∙gcat−1 from renewable bio-ethanol at 400 °C. The results from in-situ diffuse reflectance infrared Fourier transform spectroscopy suggest that geometrically adjacent Ni0 nanoparticles facilitate the oxidation of α-C in ethanol and electron-deficient Ni2+ sites promote the dehydrogenation of methyl group, further increasing H2 selectivity and suppressing the formation of CH4.

Bioethanol steam reforming over monoliths washcoated with RhPt/CeO2–SiO2: The use of residual biomass to stably produce syngas

Ethanol steam reforming of synthetic bioethanol (i.e., anhydrous ethanol plus water), as well as bioethanol obtained from glucose standards and sugarcane press-mud was evaluated on monoliths washcoated with RhPt/CeO2–SiO2. Tests with synthetic bioethanol indicated that the lower pressure drop favors higher ethanol conversion in the monoliths with respect to the powder samples. Also, two monoliths in series with 0.08 gcat/cm3 improved H2 yield compared to just one monolith with 0.16 gcat/cm3. Similarly, a decrease in the amount of carrier gas contributes to diffusion limitations in the monoliths, reducing the H2/CO ratio. Monoliths stability was also evaluated with “real” bioethanol samples (from glucose standards and sugarcane press-mud-SPM). In all cases, a syngas with >60% of H2 was produced. For SPM-bioethanol, 3.1 ± 0.2 mol H2/mol EtOH were obtained without evidence of deactivation for 120 h, at a cost of 6.9 $/kgH2, becoming a promising way to develop a technology for sustainable energy production.

Kinetic features of ethanol steam reforming and decomposition using a biochar-supported Ni catalyst

The catalytic steam reforming of bio-ethanol will provide a sustainable route for renewable hydrogen production in a future hydrogen economy. Ni catalysts will be an economically attractive alternative to noble metals. Biochar is a promising reforming catalyst or catalyst support, having shown already good activity for tar reforming. The structure of biochar, its inherent alkali and alkaline earth metallic species and the content of O-containing functional groups are factors affecting its catalytic performance. A kinetic study of ethanol steam reforming and decomposition over a biochar-supported Ni catalyst is presented in this study in order to elucidate the role of biochar in the reaction mechanism. The effects of temperature, space velocity and reactant partial pressure were investigated over a range of conditions. The chemical structural features of used biochar samples were characterized with Raman spectroscopy. Biochar itself was found to be catalytically active and participating in ethanol reforming and decomposition. It was established that the reactions on Ni and biochar active sites were not independent. Analysis of kinetic compensation effects showed commonality on biochar and suggested that the rate-limiting step occurs in the dehydrogenation pathway on the biochar surface. O-containing functional groups in biochar were observed to reduce with reforming/decomposition time.

Development and Test Performance of Heterogeneous Catalysts on Steam Reforming of Bioethanol for Renewable Hydrogen Synthesis: A Review

Development and Test Performance of Heterogeneous Catalysts on Steam Reforming of Bioethanol for Renewable Hydrogen Synthesis: A Review

Novel core-shell-like Ni-supported hierarchical beta zeolite catalysts on bioethanol steam reforming

Hierarchical-Beta zeolites have been hydrothermally synthesized by adding a new gemini organic surfactant. The used gemini surfactant play the role of a “pore-forming agents” on the mesoscale, on the same time, providing alkaline environment for the system. With this hierarchical Beta zeolite as the core support, we successfully prepared a shell layer of Ni-containing (22 wt%) petal-like core-shell-like catalyst and applied it to bioethanol steam reforming. At the reaction temperature of 350 °C–550 °C, the conversion rate of ethanol and the selectivity of hydrogen were always above 85% and 70%. After reaction of 100 h on stream at 400 °C, there were not obvious inactivation could be observed on NiNPs/OH-MBeta catalyst.

Hydrogen Production and Purification by Bioethanol Steam Reforming and Preferential Oxidation of CO

Hydrogen production and purification was studied in a combined system including double catalytic bed reaction system. Steam Reforming of Ethanol (SRE) was performed in Ni/CeO2-ZrO2 catalyst and, subsequently, the reforming products gases passed through a second fixed bed containing Au/CeO2-ZrO2 catalyst in order to carry out the preferential CO oxidation (PROX-CO). Initially, the effect of temperature and the initial water concentration in the fed ethanol were evaluated to determine the conditions that maximize the H2/CO ratio while maintaining 100% conversion of ethanol. These requirements were accomplished when 25 mol% H2O and 4 mol% C2H5OH (steam/ethanol molar ratio = 7) were used. The catalyst stability was assessed under these reaction conditions at 600 oC, during more than 160 h on stream, obtaining ethanol conversions above 99% during the entire test and H2 productivity close to ideal. In the second part of the work, in order to obtain H2 grade PEM, the effect of O2 concentration in the feed stream on the selective CO oxidation using Au-CZ catalysts was investigated in the temperature range of 50-250 oC. Catalytic stability test was also performed. Characterization techniques: Temperature Programmed Reduction (TPR), X-Ray Diffraction (XRD), SEM-EDX, which confirmed the presence of a strong interaction between the mixed oxide support and the metal. In this study, we show a reaction system with double catalytic fixed bed in which hydrogen is obtained with the specifications required by PEM fuel cell. The tested materials exhibit high activity and selectivity towards hydrogen production and CO selective oxidation in the range of temperature studied

Hydrogen, ethylene and power production from bioethanol: Ready for the renewable market?

The economic sustainability of renewable based sources is a matter of debate and the technology is changing very fast. We here considered three examples of exploitation of bioethanol as renewable source: a) centralised hydrogen prodution; b) heat and power cogeneration (residential scale); c) ethylene production. Bioethanol can be a suitable starting material for the production of H2, as fuel or chemical, or syngas. After designing the process and the implementation of kinetic expressions based on experimental data collected in our lab or derived from the literature, an economic evaluation and sensitivity analysis allowed to assess the economic sustainability of hydrogen production and purification by the steam reforming of bioethanol. The attention was mainly put on diluted bioethanol solutions, easy to purify and cost effective. The centralised hydrogen production from bioethanol was considered cost effective at least starting from diluted bioethanol from first generation crops. When dowscaling the hydrogen production and purification unit to feed a 5 kW fuel cell, the most undetermined item was the fuel cell cost, since no acclarate market price is still available.Finally, ethylene market is steadily increasing by ca. 4% each year due to economic growth. The demand for renewable ethylene, as well as the increasing oil price experienced in the recent past, suggested the development of alternative routes to ethylene. Based on the increasing availability of ethanol form renewable biomass, bioethanol-to-bioethylene processes have been recently designed, finding economic sustainability, at the moment, in Brazil.

Activity Tests of Macro-Meso Porous Catalysts over Metal Foam Plate for Steam Reforming of Bio-Ethanol.

The catalytic activity of a macro-mesoporous catalyst coated on a metal foam plate in the reforming of bio-ethanol to synthesis gas was investigated. The catalysts were prepared by coating a support with a noble metal and transition metal. The catalytic activity for the production of synthetic gas by the reforming of bio-ethanol was compared according to the support material, reaction temperature, and steam/carbon ratio. The catalysts coated on the metal foams were prepared using a template method, in which macro-pores and meso-pores were formed by mixing polymer beads. In particular, the thermodynamic equilibrium composition of bio-ethanol reforming with the reaction temperature and steam/carbon ratio to produce synthetic gas was examined using the HSC (Enthalpy-Entropy-Heat capacity) chemistry program in this study. The composition of hydrogen and carbon monoxide in the reformate gas produced by steam reforming over the Rh/Ni-Ce-Zr/Al2O3-based pellet type catalysts and metal foam catalysts that had been coated with the Rh/Al-Ce-Zr-based catalysts was investigated by experimental activity tests. The activity of the metal foam catalyst was higher than that of the pellet type catalyst.

Integrated Plant Layout for Heat and Power Cogeneration from Diluted Bioethanol

A newly developed kinetic model for the steam reforming of bioethanol has been used to simulate a fully integrated bioethanol-to-power plant. The detailed geometrical model of a tube-bundle reformer has been designed, allowing for a reliable rescaling from a molar-scale hydrogen yield to the selected target of 0.45–0.50 kg/h. This hydrogen output is suitable to grant electrical (up to 5 kW) and thermal (from 5 to 10 kW) power supply for distributed microgeneration. The feedstock cost for this cogeneration plant has been sensibly reduced with respect to other available ethanol reformers proposed in the literature, as the alcohol can be used already mixed with water, i.e., using only partially purified bioethanol. With respect to our previous feasibility studies, the system layout has been further simplified, and a qualitative analysis of the system stability has been performed in relation to a chosen control parameter (i.e., the reformer heat input): the reformer outlet temperature stabilizes at 650 °C and...

Hydrogen Production by the Steam Reforming of Bio-Ethanol over Nickel-Based Catalysts for Fuel Cell Applications

The bio-ethanol steam reforming over nickel-based catalysts when the temperature is within the range of 700 to 800 K is studied for fuel cell applications. The effect of operating conditions such as the temperature, space time, water-to-ethanol molar ratio, and oxygen-to-ethanol molar ratio on the product distribution is evaluated. The water-gas shift reaction is examined in the reforming process. Adjusting feed ratios to favor carbon removal from the surface is discussed in detail. It is shown that a nickel-supported-on-alumina catalyst completely converts bio-ethanol and high hydrogen yields are obtained. High temperatures and water-to-ethanol ratios can promote hydrogen production. There is no evidence that the water-gas shift reaction occurs over nickel-based catalysts. Carbon formation can be minimized by using high water-to-ethanol ratios. The presence of oxygen in the feed plays a favorable effect on the carbon deposition, but the carbon monoxide production is not reduced. There are several reaction pathways that could occur in the bio-ethanol steam reforming process, and the catalyst produces ethylene and acetaldehyde as intermediate products. The region of carbon formation depends on the temperature as well as the water-to-ethanol and oxygen-to-ethanol molar ratios. Finally, an overall reaction scheme as a function of temperature is proposed. The best catalysts appear to be those that are sufficiently basic to inhibit the dehydration of ethanol to ethylene, which subsequently polymerizes and causes coke formation.