Steam Reforming Of Ethylene Glycol Research Articles

Efficacy of Lithium Zirconate-Based Bifunctional Materials to Produce High-Purity Hydrogen via Sorption-Enhanced Ethylene Glycol Steam Reforming

Efficacy of Lithium Zirconate-Based Bifunctional Materials to Produce High-Purity Hydrogen via Sorption-Enhanced Ethylene Glycol Steam Reforming

Steam reforming of monohydric alcohols and polyalcohols: Influence of single or multiple hydroxyl group(s) on nature of the coke

Alcohols like ethanol and glycerol have been extensively investigated as potential feedstock for on-site hydrogen production by steam reforming. The varied number of hydroxyl group in the alcohols inevitably affects the reaction intermediates generated and eventually properties of coke formed. In this study, four alcohols (ethanol, ethylene glycol, 1-propanol and glycerol) with the single or multiple hydroxyl groups were steam reformed, focusing on the influence of the hydroxyl group on the properties of the coke. The research results showed that steam reforming of ethanol and glycerol produced more coke than that in steam reforming of 1-propanol or ethylene glycol, while the Ni/SBA-15 catalyst deactivated to a higher extent in steam reforming of ethylene glycol or glycerol with multiple hydroxyl group, due to the coke of varied properties. The coke produced by steam reforming of ethanol and 1-propanol contained more defective structures but more aromatic. However, the generated coke from the steam reforming of ethylene glycol and glycerol had more aliphatic structures, especially in that from ethylene glycol. On the other hand, the carbon nanotubes formed by the steam reforming of ethanol or 1-propanol had thin wall thickness and smooth surface, while that in steam reforming of ethylene glycol and glycerol had thick wall and very rough surface, resulting from the distinct reaction intermediates formed.

Catalytic performance and kinetic modeling of ethylene glycol steam reforming over surfactant-modified Pd–Ni/KIT-6

In the current study, steam reforming of ethylene glycol as a well-known bio-oxygenate, was carried out over 2%Pd–10%Ni/KIT-6 catalyst in a fixed-bed reactor. 2%Pd–10%Ni/KIT-6 was synthesized via surfactant-assisted impregnation method, whose physicochemical properties were determined by XRD, XRF, BET, FE-SEM, EDX-dot mapping, TEM, H 2 -TPR, NH 3 -TPD and TGA analyses. The performance of the synthesized catalyst was investigated at temperatures from 623 to 773 K and at 10 wt% of ethylene glycol in water. Furthermore, the W cat /F EG0 ratio varied between 100.08 and 202.22 (g h mol −1 ). At T = 773 K and W cat /F EG0 = 202.22, ethylene glycol conversion and H 2 yield were 99.8% and 71.36%, respectively. Also, a stability test of 2%Pd–10%Ni/KIT-6 was conducted for 28 h. No significant change was shown in the catalytic activity. Some different models were used to describe the kinetic behavior. The power-law model indicated that the reaction order changed with temperature. The kinetic data were interpreted by the Langmuir-Hinshelwood models, in which the surface reaction between the adsorbed reactants was considered as a rate-determining step. The activation energy for the Langmuir-Hinshelwood and power-law models were 28.03 and 33.07 kJ mol −1 , respectively. This synthesized nanocatalyst as the first Pd–Ni/zeolite in SREG through well-known kinetics and mechanism, is superior in high stability, excellent EG conversion, good yield and selectivity to H 2 and less production of toxic products. • 2%Pd–10%Ni/KIT-6 was prepared by surfactant-assisted-impregnation method. • EG steam reforming over Pd–Ni/KIT-6 was carried out at various operating conditions. • Highest H 2 selectivity and EG conversion were achieved at 773 K and WHSV of 3 h −1 . • Kinetic modeling was done using the power-law and Langmuir-Hinshelwood models.

Hydrogen production using ethylene glycol steam reforming in a micro-reformer: Experimental analysis, multivariate polynomial regression and genetic programming modeling approaches

Three types of catalysts, i.e. Pt/γ-alumina (PGA), Ni/γ-alumina (NGA) and Ni–Pt/γ-alumina (NPGA), were prepared by incipient wetness impregnation (IWI) and deposited on a micro-reformer for hydrogen production by ethylene glycol steam reforming (EGSR). Multivariate polynomial regression (MPR) and genetic programming (GP) approaches were used to model the EGSR process based on experimental data. In these models, temperature and weight hourly space velocity (WHSV) as independent variables and ethylene glycol (EG) conversion, H2 selectivity, H2 yield and CO selectivity were considered as target functions. Based on the results, the GP model predicts objective functions with the highest prediction power and this model was selected as the optimal model. For example, for the NGA catalyst and the dependent variable of EG conversion, the values of correlation coefficient (R2) and root mean squared error (RMSE) were 0.9980 and 1.3191, respectively based on the GP model while for the best MPR (cubic) model; these parameters were 0.9735 and 4.2476, respectively. The results showed that the EG conversion values for the NPGA bimetallic catalyst were higher than for the PGA or NGA monometallic catalysts. The maximum values of EG conversion, H2 selectivity and H2 yield for all the catalysts were obtained at a temperature of 450 °C and at a WHSV of 80.8 h−1.

Sustainable and selective hydrogen production by steam reforming of bio-based ethylene glycol: Design and development of Ni–Cu/mixed metal oxides using M (CeO2, La2O3, ZrO2)–MgO mixed oxides

Hydrogen (H2) production in a clean and green manner via renewable sources is at present of great interest. Ethylene glycol, a bio-based feedstock, offers a sustainable route for high purity H2 production. In the current investigation, MgO based mixed metal oxides containing CeO2, La2O3 and ZrO2 were synthesized and used to support 20 wt% Ni–Cu (1:1). The impacts of altering support characteristics on catalytic behavior have been studied and compared in H2 synthesis via ethylene glycol steam reforming (SR), employing various characterization techniques such as XRD, SEM, EDX, TEM, H2-TPR, H2-TPD, TG-DSC and BET. Further, high resolution XPS studies were performed to explore the valence states and effectiveness of surface engineering of the catalysts. Assessment of the efficacy of catalysts was done via several parameters such as reactant conversion, H2 concentration and long-term stability. All the synthesized materials produced encouraging results with high H2 yield and conversion under the said operating conditions [T- 623 to 773 K; GHSV - 3120 to 6240 h−1; P - 0.1 MPa; S/C - 3 to 7.5 mol/mol]. Amongst the three catalysts, Ni–Cu/La2O3–MgO and Ni–Cu/CeO2–MgO exhibited superior behavior for high H2 production. Ni–Cu/La2O3–MgO was better in comparison to Ni–Cu/CeO2–MgO in terms of reactant conversion whereas Ni–Cu/CeO2–MgO showed highest H2 concentration (98 mol %) and improved stability along with absence of carbon deposition owing to its high mobile oxygen vacancies in its lattice. The highly active cubic CeO2 species and its long-term durability (up to 8 cycles) owing to its exceptional redox property further justified its efficacy. The optimized process showed that at T = 773 K, GHSV = 3120 h−1, S/C = 4.5 mol/mol for Ni–Cu/La2O3–MgO and Ni–Cu/CeO2–MgO and at T = 773 K, GHSV = 3120 h−1, S/C = 6 mol/mol and for Ni–Cu/ZrO2–MgO, maximum H2 concentration was obtained. At the end, reaction pathway followed by the catalysts was proposed.

Improvement of low temperature activity and stability of Ni catalysts with addition of Pt for hydrogen production via steam reforming of ethylene glycol

Hydrogen production by steam reforming of ethylene glycol (EG) at 300 °C was investigated over SiO2 and CeO2 supported Pt–Ni bimetallic catalysts prepared by incipient wetness impregnation methods. It was observed that impregnation sequence of Pt and Ni can affect the performance of catalysts apparently. Catalyst with Pt first and then Ni addition showed higher EG conversion and H2 yield owing to the Ni enrichment on the surface and the proper interaction between Pt and Ni. It was observed that although SiO2 supported catalysts exhibited better activity and H2 selectivity, CeO2 supported ones had better stability. This is attributed to the less coke formation on CeO2. Increasing Pt/Ni ratio enhanced the reaction activity, and Pt3–Ni7 catalysts with 3 wt% Pt and 7 wt% Ni showed the highest activity and stability. Ni surficial enrichment facilitated the C—C bond rupture and water gas shift reactions; and Pt addition inhibited methanation reaction. Electron transfer and hydrogen spillover from Pt to Ni suppressed carbon deposition. These combined effects lead to the excellent performance of Pt3–Ni7 supported catalysts.

Hydrogen production via steam reforming of ethylene glycol over Attapulgite supported nickel catalysts

Steam reforming of ethylene glycol was investigated over Ni-based catalysts supported on Attapulgite (ATP; originating from Jiangsu (JS), Anhui, and Gansu (GS) provinces in China). N2 adsorption–desorption, XRD, FTIR, H2-TPR, NH3-TPD, SEM, and TEM-EDS measurements were performed to analyze the catalyst properties. The results revealed that Ni/ATPGS had the largest particle size (17.9 nm) and the highest reductive degree (98.0%). Consequently, Ni/ATPGS showed the highest ethylene glycol conversion (97.2%) during the first 4 h of reaction. However, this catalyst showed the lowest H2 yield (71.2%), possibly owing to large Ni particle sizes as well as ample surface acidic sites and acidity, leading to a high selectivity toward CH4 (20.8%) and C2H4 (2.2%). In contrast, Ni/ATPJS presented the highest H2 yield (89.8%) owing to it having the smallest Ni particle sizes and lowest amount of surface acidic sites. Additionally, this catalyst showed the highest stability over 8 h of reaction. An examination of the spent catalysts revealed that Ni/ATPJS possessed excellent antisintering and coking properties.

Renewable hydrogen production by ethylene glycol steam reforming over Al2O3 supported Ni-Pt bimetallic nano-catalysts

Abstract The steam reforming of ethylene glycol, a simple model compound for biomass-derived liquids, is considered to be an environmentally green process for producing renewable hydrogen. Both Pt and Ni species are known for their catalytic activity under steam reforming reaction conditions. In this investigation, alumina supported Ni-Pt bimetallic catalysts (X wt% Ni-Y wt% Pt/Al2O3 named XNi-YPt) were employed for steam reforming of ethylene glycol. The prepared catalysts were characterized by XRD, BET, H2-TPR, H₂-Chemisorption, and TEM. It was observed that Ni/Pt ratio strongly affected the redox behavior, BET surface area, and particle size of the samples that in turn affected their catalytic performance. The optimum catalyst sample was 3.75Ni-1.25 Pt which resulted in the highest ethylene glycol conversion (60%), highest H2 selectivity (45%) and yield (27%), and a minimum of 20 h of stability due to the lowest amount of coke formed the catalyst surface. The overall order of the catalytic performance of the samples was as follows: 3.75Ni-1.25 Pt > 2.5Ni-2.5 Pt > 1.25Ni-3.75 Pt > 0Ni-5Pt > 5Ni-0Pt. A kinetic model for the steam reforming of ethylene glycol in a packed bed reactor containing the 3.75Ni-1.25 Pt catalyst was employed indicating a good agreement between experimental and predicted H2 selectivity and yield. Intrinsic reaction rate data in the absence of the heat and mass transfer limitations were obtained in parametric studies (Temperature range of 823–893 K, ethylene glycol mole fraction range of 0.056–0.116 and bed density of 18–26 kg m−3). Higher temperature and bed density and lower ethylene glycol mole fraction enhanced the reactivity. The maximum ethylene glycol conversion (70%), H2 yield (36.5%) and H2 selectivity (52%) was observed for conditions of 893 K, bed density of 24 kg m−3 and ethylene glycol mole fraction of 0.056.

Evaluation of a micro-channel reactor for steam reforming of ethylene glycol: A comparative study of catalytic activity of Pt or/and Ni supported γ-alumina catalysts

Steam reforming of ethylene glycol (EG) was studied using γ-alumina supported 12%Ni, 3%Pt and 3%Pt12%Ni catalysts, in a micro-channel reactor. The parallel micro-channels were etched on a stainless steel plate using micro-milling technique with high speed CNC machine. The catalysts were prepared by the incipient wetness impregnation method and were characterized by using XRD, BET, FE-SEM, H2-TPR and TGA analyses. The effects of reaction temperature and feed flow rate on the EG conversion, hydrogen yield and selectivities of the gaseous products were investigated. Experimental findings revealed that 3%Pt12%Ni/γ-alumina catalyst can provide the highest EG conversion (96.1%) with 76.6% hydrogen yield and 5.3% CO selectivity at 450 °C temperature and 4 mL h−1 feed flow rate. Furthermore, continuous EG steam reforming identified 3%Pt12%Ni/γ-alumina as the most stable catalyst. This catalyst can remain stable after being on stream for more than 20 h.

Sorption‐Enhanced Steam Reforming of Ethylene Glycol over Dual Functional Hydrotalcite Materials Promoted with Pt and Ru

AbstractCatalytic steam reforming of renewable bio‐oxygenates coupled with on‐site carbon dioxide (CO2) capture is a potential option for sustainable hydrogen (H2) production. The current work focuses on high‐purity H2 production over modified hydrotalcite (HTlc) based multi‐functional hybrid materials via sorption‐enhanced steam reforming of ethylene glycol. The unpromoted hybrid material (HM1) was copper‐based HTlc, integrated with nickel. HM1 was promoted with platinum and ruthenium to yield two novel hybrid materials (Pt‐HM1 and Ru‐HM1). The performance of HM1, Pt‐HM1 and Ru‐HM1 was compared. Our lab‐made hybrid materials exhibited encouraging performance, e. g., improved H2 production, less by‐product formation, long‐term stability and no coking. Particularly, promotion of the hybrid materials with platinum and ruthenium proved beneficial, due to the high H2 concentration in the product stream (98.6 and 93.2% for Pt‐HM1 and Ru‐HM1). Interestingly, the adsorption capacity of Ru‐HM1 (1.3 mol CO2 kg sorbent−1) was higher than that of Pt‐HM1 (0.93 mol CO2 kg sorbent−1) and HM1 (0.43 mol CO2 kg sorbent−1) at their optimal conditions. The cyclic resilience of the hybrid materials was also encouraging. Ru‐HM1, Pt‐HM1 and HM1 remained durable for 22, 16 and 8 cycles, correspondingly. Finally, a likely reaction mechanism followed over the hybrid materials was proposed.

Experimental study of 2-methoxyethanol steam reforming in a membrane reactor for pure hydrogen production

For the first time, 2-methoxyethanol (C3H8O2) was used for producing pure hydrogen in a catalytic membrane reactor (CMR) via steam reforming (SR). The SR experiments were performed at 923K and 1–10bar using a mixture of 2-methoxyethanol (MEX) and water at S/C ratio of 3. Moreover, SR experiments were performed under the same operating conditions using ethylene glycol (EG), methanol (MET), and a mixture of EG+MET, keeping a constant carbon molar flow rate into the CMR to study the reaction pathway through which 2-methoxyethanol is converted to SR products (CH4, CO, CO2, and H2). Hydrogen recovery values of up to 90% and pure hydrogen yields of 0.5 and 0.63 at 10bar were reached in the case of the steam reforming of MEX and EG+MET, respectively. An outstanding value of 4mol of pure hydrogen per mol of MEX was obtained at 10bar. The presence of methanol promoted the SR of EG. The experimental results showed that 2-methoxyethanol is a promising source for producing hydrogen, especially in a CMR where a better efficiency (complete fuel conversion and high hydrogen yield) is reached.

Steam reforming of ethylene glycol over Ni-based catalysts: the effect of K

The effect of K on the activities of Ni/Al2O3 catalysts in steam reforming of ethylene glycol was investigated. Ni/Al2O3 catalysts were prepared by incipient wetness impregnation and co-precipitation methods. The addition of K was achieved using an incipient wetness impregnation method. The prepared catalysts were characterized by N2 physisorption, inductively coupled plasma-atomic emission spectroscopy, X-ray diffraction, temperature-programmed reduction, and scanning electron microscopy. Irrespective of the preparation method, the promotional effect of K was observed and the optimum K content (~5 wt%) was verified for K-promoted Ni/Al2O3 catalysts. The addition of K to the Ni–Al2O3 catalyst prepared by co-precipitation led to higher catalytic activity than addition of K to the Ni/Al2O3 catalyst prepared by incipient wetness impregnation.

Hydrogen production from steam reforming of ethylene glycol over supported nickel catalysts

A series of nickel catalysts were prepared by the impregnation and co-precipitation methods and characterized by X-ray diffraction, nitrogen physisorption, and H2 temperature-programmed reduction. The effects of nickel loading, calcination temperature, reaction temperature, support modification and cobalt oxide addition on the catalytic activity and selectivity to H2 in the steam reforming of ethylene glycol were investigated. The results indicate that the nickel catalyst prepared by co-precipitation has smaller particle size and relatively higher activity in comparison with the catalyst prepared by impregnation. Adding a small amount of cobalt oxide to the Ni/CeO2 catalysts can enhance the catalytic activity; over the Ni-Co bimetallic catalyst, the yield of hydrogen reaches 72.6%. Modifying CeO2 with Al2O3, TiO2 and ZrO2 also has a certain influence on the catalytic activity and the Ni/CeO2-Al2O3 catalyst exhibits the highest activity, with an ethylene glycol conversion of 94% to gaseous products and a hydrogen yield of 67%. However, Ni/CeO2-SiO2 shows a very low activity in spite of its large surface area and pore volume.

Steam Reforming of Alcohols for Hydrogen Production

To understand the complexity of the reactions involved in the steam reforming of glycerol and with the aim of identifying the contribution of C-C and C-O bonds cleavage, in this work we have studied the steam reforming of C3 alcohols simpler than glycerol such as 1-propanol, 2-propanol, 1,2-propanediol and 1,3-propanediol. A Pt/SiO2 catalyst was employed and were studied the conversion and the product distribution for each alcohol. It was possible to determine the absence of C-O and C-C bonds cleavage in a secondary alcohol such as 2-propanol and 1,2 propanediol. The presence of reaction intermediates with an aldehyde function, deactivates the catalyst due to their strong adsorption on the metal site, moreover, the presence of hydroxyl-aldehydes promotes the C-C bonds cleavage favoring the gas production. The reaction pathway from glycerol to acetol by cleavage C-O bonding or dehydration on metal site is responsible for the subsequent reactions leading to deactivation. The main reaction pathway to obtain gaseous products from glycerol reforming involve C-C bonds cleavage of primary alcohols such as 2,3-dihydroxypropanal, 1,2-ethanediol and 2-hydroxyethanal. In order to confirm the proposed reaction pathways, steam reforming of ethylene glycol was performed, identifying this compound as primary intermediates to obtain gaseous products from glycerol. Keywords: C3-alcohols, platinum catalyst, steam reforming, hydrogen production.

On the Efficacy of Ru/Al2O3 Catalyst for Steam Reforming of Ethylene Glycol

This work describes hydrogen (H2) production via steam reforming of ethylene glycol (EG) over a supported ruthenium catalyst. EG is chosen as a model compound for the alcohols contained in the aqueous phase of bio-oil. Using a fixed-bed reactor, experimental runs are carried out over Ru/Al2O3 at various temperatures (350–500°C), ratios of the mass of the catalyst (W) to the molar flow rate (FO) of EG at the inlet (W/FO = 0.37 − 2.38 g h/mol), and feed concentrations (22.3–53.4 wt.% EG in water). The role of Ru in conversion of EG, production of H2, and product distribution of the carbonaceous species is studied. Reaction pathways previously described in the literature are used to elucidate our results.

Comparison of Ethylene Glycol Steam Reforming Over Pt and NiPt Catalysts on Various Supports

Steam reforming of ethylene glycol (EG) was studied on Pt and NiPt catalysts supported on γ-Al2O3, TiO2, and carbon. On all supports bimetallic NiPt catalysts show higher activity for H2 production than the corresponding Pt catalysts as predicted from model surface science studies. The kinetic trends are similar for all catalysts (Pt and NiPt) with the H2 production rate being zero-order and fractional order with respect to water and ethylene glycol, respectively. Slight differences in selectivity to minor products are observed depending both on active metal and support. On γ-Al2O3, NiPt shows higher H2 and less alkane formation than Pt. TiO2 supported catalysts show increased water-gas shift activity but also increased selectivity to alkane precursors. NiPt/C is identified as an active and selective catalyst for EG reforming.

Microkinetic modeling of Pt-catalyzed ethylene glycol steam reforming

A predictive mean-field microkinetic model is developed for steam reforming of ethylene glycol over a Pt catalyst using a hierarchical multiscale modeling approach. The model's predictive capabilities are assessed by comparison to experimental data under kinetically controlled conditions. It is found that early dehydrogenation reaction steps control the reaction rate, highlighting a kinetic analogy between ethylene glycol steam reforming and CH4 steam reforming on Pt catalysts.

On the origin of reactivity of steam reforming of ethylene glycol on supported Ni catalysts

This paper describes a strategy for producing hydrogen via steam reforming of ethylene glycol over supported nickel catalysts. Nickel plays a crucial role in conversion of ethylene glycol and production of hydrogen, while oxide supports affect product distribution of carbonaceous species. A plausible reaction pathway is proposed based on our results and the literature.

Sustainable hydrogen production for fuel cells by steam reforming of ethylene glycol: A consideration of reaction thermodynamics

The use of renewable biomass, such as ethylene glycol (EG), for hydrogen production offers a more sustainable system compared to natural gas and petroleum reforming. For the first time, the reaction thermodynamics of steam reforming and sorption enhanced steam reforming of EG have been investigated. Gibbs free energy minimization method was used to study the effect of pressure (1–5 atm), temperature (500–1100 K) and water to EG ratio (WER 0–8) on the production of hydrogen and the formation of associated by-products (CH 4, CO 2, CO, C). The results suggest that hydrogen production is optimum when steam reforming occurs at atmospheric pressure, 925 K and with a WER of 8. Moreover, working at high temperature (>900 K) and with a WER above 6 inhibits almost entirely the production of methane and carbon. The main source of hydrogen in the system is found to be steam reforming of methane and water gas shift reaction by the analysis of the response reactions (RERs). Hydrogen production is governed by the former reaction at low temperatures while the latter one comes into prominence as temperature increases. By coupling with in situ CO 2 capture using CaO, the formation of CO 2 and CO can be avoided and high purity of hydrogen (>99%) can be achieved.