Comparison of perennial grasses and corn-based biomass materials for high-yielding hydrogen gas production

Both perennial grasses and corn biomass residues are non-edible for humans and have high carbohydrate contents that make them promising raw materials for biofuel production. This study evaluated perennial grasses (miscanthus and switchgrass) and corn-based biomass materials (corn stover, stalk, cob, husk, and bran) for high-yielding hydrogen gas production by aqueous-phase reforming (APR). The biomass materials were dissolved in subcritical water to obtain hydrolysates for use as feed solutions in APR. The dissolution experiments showed that hydrolysis percentages and total organic carbon releases were considerably higher in corn biomass fractions as compared to perennial grasses. The highest (66.7 mL H2) and lowest (27.0 mL H2) hydrogen yields were observed when miscanthus and corn bran biomass hydrolysates, respectively, were used as the feed solution. Hydrogen production yields were found to be in the following descending order: Miscanthus > corn cob > corn stover > switchgrass > corn husk corn stalk >> corn bran. In general, the biomass hydrolysates that had less organic carbon resulted in higher hydrogen production. Hydrolysis and gasification results for corn husks from various types of corn (field corn, sweet corn, seed corn, and popcorn) were different. The findings of this study will be beneficial for selection of the right biomass material for production of a specific value-added product from biomass. This study focused on biofuel hydrogen gas, which has the highest specific energy content of all conventional fuels. © 2017 American Society of Agricultural and Biological Engineers

Electrolysis of coal slurries to produce hydrogen gas: Effects of different factors on hydrogen yield

The study was aimed to investigate the effects of different factors (such as acid concentration, cell potential, temperature, coal types, and geometric area of the membrane) on the coal slurry electrolysis and hydrogen evolution. It was observed that all of the above factors affected hydrogen production upon completion of the electrolysis. The results revealed that an increase in the initial acid concentration up to 5.0 M brought about an increase in the current density and hydrogen evolution. However, the higher the acid concentration was taken (>7.0 M) then the lower the current density and hydrogen evolution were, which resulted in significant change due to the agglomeration of coal samples and stuck on the electrode surface. Furthermore, the CO2 evolution (14 ml) was observed only at high temperature (100 °C) and high (2.0 V) cell potential when the H2 amount was 776 ml. The coal type was observed to have influenced the electrolysis. © 2011, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.MAG 106M306 Çukurova ÜniversitesiFinancial supports from Scientific and Technical Research Council of Turkey (TUBITAK, the project number: MAG 106M306) and Çukurova University Research Fund are gratefully acknowledged

Production of activated carbon materials from kenaf biomass to be used as catalyst support in aqueous-phase reforming process

In the present study, low value-added woody biomass, kenaf (Hibiscus cannabinus L.), was utilized for production of activated carbons (ACs) that can be used as catalyst support for deposition of metal particles such as Pt to produce highly active catalysts for gasification of biomass hydrolysates by aqueous-phase reforming (APR) process. H3PO4 was used as activating agent for production of AC materials. ACs produced from kenaf and non-hydrolyzed fraction of kenaf after dissolution in subcritical water were compared with the commercial one. The activated carbon material from kenaf had highest BET surface area and total pore volume among the materials tested including commercial AC. The catalyst prepared by Pt deposition on this material (kenaf AC-Pt) had also highest BET surface area and total pore volume. This catalyst exhibited very high activity and selectivity for hydrogen production (0.015 mol H2/g catalyst) in APR of biomass hydrolysate. © 2016 Elsevier B.V. All rights reserved

Preparation of activated carbon supported Pt catalysts and optimization of their catalytic activities for hydrogen gas production from the hydrothermal treatment of biomass-derived compounds

In the fields of energy science, it is a challenging issue to develop a highly active catalyst for hydrogen-rich gas production from biomass-derived compounds. In the present study, active reforming catalysts for use of gasification of glucose, biomass-derived compound, in aqueous medium were developed by deposition of platinum on active carbon (AC) support using nanotechnological approaches in supercritical carbon dioxide (ScCO 2) media and impregnation (IMP) in aqueous media. Effects of reduction methods for platinum metal and chemical treatment for AC support were evaluated for hydrogen production activity. It was observed that reduction of platinum precursor first by NaBH 4 and then heat treatment resulted in more active catalysts compared to one single reduction method applied. The metal particles deposited on AC in ScCO 2 had smaller sizes than those prepared by IMP in aqueous media. In case of IMP catalysts, NaBH 4 and heat treatment double reduction methods applied catalysts showed greater activity for hydrogen production than those prepared by ScCO 2 deposition technique. Activity of CH 3COOH and HCl treated supports exhibited higher catalytic performance compared to H 3PO 4 and KOH treated supports however, untreated AC had still better activity in hydrogen production. Copyright © 2012, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.Çukurova Üniversitesi: FEF2011D18The authors thank NORIT Inc. (The Netherlands) for generously providing activated carbon used in this study. Financial support from Çukurova University is gratefully acknowledged (Project number: FEF2011D18 )

Xylitol production from lignocellulosics: Are corn biomass residues good candidates?

Pentosan-rich fractions of biomass materials have potential for production of value-added product, xylitol. Xylitol is widely used as a sugar substitute in food industry but it is also a building block for a variety of commodity chemicals. Xylitol is one of top 12 high value-added intermediate chemicals that can be produced from biomass. Present study evaluated corn biomass residues (corn stover, husk, and cob) and corn bran as alternative raw materials for xylitol production. The productions were performed by chemical and thermochemical routes that were based on releasing of xylose sugar from the materials and then reduction of the hydrolysates for xylitol formation. The results showed that the use of isolated hemicellulose fraction versus biomass material itself as starting material produced more concentrated xylitol with fewer amounts of byproducts. Corn bran is the best alternative raw material to produce xylitol compared to corn stover, husk and cob. The yield of xylitol was observed to be higher in chemical method in the conditions studied. © 2017 Elsevier LtdUniversity of Nebraska-Lincoln: 1024460Financial support from University of Nebraska-Lincoln is gratefully acknowledged (Foundation fund name and number: Layman 1024460)

Hydrogen production from aqueous-phase reforming of sorghum biomass: An application of the response surface methodology

Aqueous-phase reforming (APR) of sorghum hydrolyzate was performed in a fixed bed reactor applying response surface methodology (RSM) based on the Box-Behnken design (BBD) to produce hydrogen gas. The results showed that RSM based on the BBD was a well-matched method for optimizing of APR of sorghum hydrolyzate. The independent variables such as interactive effects of temperature, feed flow rate, and carbon content of sorghum hydrolyzate on the APR were investigated. The mathematical model and experimental results showed that the operation temperature was the main positive linear effect whereas the interaction between temperature and feed flow rate was the main negative linear effect on the hydrogen yield. The highest hydrogen production was found to be a temperature of 270°C, a hydrolyzate flow rate of 0.30mL/min, and a carbon content of biomass concentration of 2500mg/L. The highest H2/CO2 mole ratio (7.9) obtained at 270°C when carbon content of sorghum hydrolyzate was 1000mg/L. © 2013 Elsevier Ltd.FEF2010BAP11Financial support from Çukurova University Research Fund is gratefully acknowledged (Project number: FEF2010BAP11 ). The authors would like to thank to Dr. Deniz Yildirim for his valuable comments on RSM results

Does reduced or non-reduced biomass feed produce more gas in aqueous-phase reforming process?

There has been increasing interest in the production of gaseous and liquid biofuels from biomass. Biomass feed type and its content to be used in the conversion process are very important parameters to produce high yield biofuel. In this study, reduced and non-reduced forms of biomass-derived compound (glucose) and actual biomass hydrolysate feeds were evaluated to produce hydrogen-rich gas mixture by aqueous-phase reforming (APR) in presence of supported Ru catalyst. Various hydrogenation conditions were tested for effective conversion. The results showed that reduced solutions always produced significantly higher gas yield with high hydrogen selectivity. Although biomass hydrolysate was composed of variety of complex compounds, it exhibited significantly better performance compared to glucose, simple biomass model compound. © 2014 Elsevier Ltd. All rights reserved

Utilization of waste cotton linter for preparation of activated carbon to be used as catalyst support in aqueous-phase reforming process

Waste cotton linter was evaluated for production of activated carbons (ACs) that can be used as catalyst support in aqueous-phase reforming (APR) process. Activated carbons were prepared by two different precarbonization methods (thermal and hydrothermal) and two types of chemical activating agents (H 3 PO 4 and KOH). The catalysts prepared by deposition of platinum particles on these carbon materials were evaluated for conversion of glycerol to hydrogen gas by APR. Thermal precarbonization treated LTA and LTB samples had a higher surface area (416.7 and 775.2 m 2 /g) than hydrothermal precarbonized LHA and LHB samples (395.8 and 627.5 m 2 /g) regardless type of the activating agent. In general, KOH was more effective activating agent than H 3 PO 4 in creating porosity in the carbon structures derived from cotton linter. The Pt/LHB catalyst (hydrothermal precarbonization-KOH activation) showed promising catalytic performance with hydrogen selectivity of 76.0% and 99.0% glycerol conversion at same APR conditions. © 2018 American Institute of Chemical Engineers Environ Prog, 38: 445–450, 2019. © 2018 American Institute of Chemical Engineer

Influence of particle size of support on reforming activity and selectivity of activated carbon supported platinum catalyst in APR

The aqueous-phase reforming (APR) of biomass-derived compounds has been considered as a promising way to produce hydrogen and developing active reforming catalysts for this process is the challenging issue. The current research was conducted to determine the effect of particle size of support on activity and hydrogen selectivity of activated carbon supported platinum catalyst for APR of glucose, biomass-derived model compound. The commercial activated carbon material was pounded and fractionated based on particle size using 60, 80 and 170 mesh sieves. The activated carbon supported Pt catalysts were prepared by deposition of Pt metals on those fractions by incipient wetness impregnation method. The results showed that although Pt particles deposited on the pounded supports were same size, smaller-sized activated carbon supported Pt catalyst exhibited higher activity and hydrogen selectivity. The performance of the catalyst was better when narrower size distribution of the support particles was used. © 2014 Elsevier Ltd. All rights reserved

Biofuel production by liquefaction of kenaf (Hibiscus cannabinus L.) biomass

PubMedID: 24262837In this study, kenaf biomass, its dried hydrolysate residue (solid residue left after removing water from hydrolysate) and non-hydrolyzed kenaf residue (solid residue left after hydrolysis process) were liquefied at various temperatures. Hydrolysis of biomass was performed in subcritical water condition. The oil. +. gas yield of biomass materials increased as the temperature increased from 250 to 300. °C. Increasing temperature to 350. °C resulted in decreases in oil. +. gas contents for all biomass feeds studied. On the other hand, preasphaltene. +. asphaltene (PA. +. A) and char yields significantly decreased with increasing the process temperature. The use of carbon or activated carbon supported Ru catalyst in the process significantly decreased char and PA. +. A formations. Oils produced from liquefaction of kenaf, dried kenaf hydrolysate and non-hydrolyzed kenaf residue consist of fuel related components such as aromatic hydrocarbons, benzene and benzene derivative compounds, indane and trans/cis-decalin. © 2013 Elsevier Ltd