In-situ catalytic upgrading of biomass pyrolysis vapor: Co-feeding with methanol in a multi-zone fixed bed reactor

The in-situ catalytic upgrading of the biomass pyrolysis vapor and its mixture with methanol were conducted in a fixed bed multi-zone reactor. The steps were comprised; thermally converting the biomass in the pyrolysis reactor, passing its vapor in contact with the HZSM-5 zeolite catalyst in the presence of methanol vapor, and transformation of the resulting upgraded pyrolysis vapor into the liquid product. The biomass pyrolysis and catalytic pyrolysis vapor upgrading were performed at 500 degrees C. The highly valuable chemicals production was a function of the hydrogen to carbon effective ratio (H/C-eff) of the feed. This ratio was regulated by changing the relative amount of biomass and methanol. More aromatic hydrocarbons (50.02 wt.) and less coke deposition on the catalyst (1.3 wt.) were yielded from the biomass, when methanol was co-fed to the catalytic pyrolysis process (H/C-eff = 1.35). In this contribution, the deposited coke on the catalyst was profoundly investigated. The coke, with high contents of oxo-aromatics and aromatic compounds, was generated by polymerization of biomass lignin derived components activated by catalyst acid sites. (C) 2015 Elsevier Ltd. All rights reserved

Co-production of hydrogen and carbon nanofibers from methane decomposition over zeolite Y supported Ni catalysts

The objective of this paper is to study the influences of different operating conditions on the hydrogen formation and properties of accumulated carbon from methane decomposition using zeolite Y supported 15 and 30 Ni, respectively, at a temperature range between 500 and 650 degrees C in a pilot scale fixed bed reactor. The temperature ramp was showed a significant impact on the thermo-catalytic decomposition (TCD) of methane. An optimum temperature range of 550-600 degrees C were required to attain the maximum amount of methane conversion and revealed that at 550 and 600 degrees C, catalyst showed longer activity for the whole studied of experimental runs. Additionally, at 550 degrees C, the methane decomposition is two times longer for 30 Ni/Y zeolite than that for 15 Ni/Y zeolite catalyst, whereas it is almost three times higher at 500 degrees C. A maximum carbon yield of 614.25 and 157.54 g(c)/g(Ni) were reported after end of the complete reaction at 600 degrees C with 30 and 15 Ni/Y zeolite catalyst, respectively. From BET, TPD, and XRD analysis, we had reported that how the chemistry between the TCD of methane and metal content of the catalysts could significantly affect the hydrogen production as well as carbon nano-fibers. TEM analysis ensured that the produced carbon had fishbone type structures with a hollow core and grew from crystallites of Ni anchored on the external surface of the catalysts and irrespective of the metal loadings, the whisker types of nano filaments were formed as confirmed from FESEM analysis. Nevertheless, the effect of volume hourly space velocity (VHSV) on the methane conversion was also investigated and reported that the methane conversion increased as VHSV and nickel concentration in Ni-Y catalysts increased. Additionally, the initial methane decomposition rate increases with VHSV and it has reverse and non-linear relevancy to the weight of Ni/Y zeolite catalyst. (C) 2014 Elsevier Ltd. All rights reserved

Parametric and adsorption kinetic studies of reactive black 5 removal from textile simulated wastewater using oil palm (Elais guineensis) empty fruit bunch

The potential of using Empty Fruit Bunch (EFB), an agrowaste material, as a low-cost biosorbent for the removal of Reactive Black 5 (RB5) from aqueous solution was investigated in this study. The influences of solution pH, contact time, initial concentration and biosorbent dosage were studied in batch experiments at room temperature. Adsorption equilibrium was achieved after 30 min of agitation. The maximum adsorption uptake of RB5 dye occurred at pH 2, resulting in a rapid adsorption (more than 50% RB5 uptake) for the first 5 min of contact. Lower solution pH values showed better adsorption because the dye molecules tend to adsorb on positively charged adsorbent sites. Furthermore, higher biosorbent dosages increased the dye uptake by up to 90% due to the availability of more active adsorption sites. Both the pseudo-second-order kinetic model and the Langmuir model indicated that monolayer coverage on the adsorbent was dominant and that chemisorption was the rate-determining ste

Optimization of reactive dyes degradation by Fenton oxidation using response surface method

The objective of this study is to determine the influence of various parameters on the degradation of dye (with high COD value) by using Fenton process. Design of experiment was applied for the optimization with respect to: initial concentration of Fe2+ and H2O2 to ascertain their respective effects on the treatment efficiency. The progress of dye degradation was analyzed by monitoring the Chemical Oxygen Demand (COD). The experimental results show that the initial concentration of H2O2, and Fe2+, had great influence on degradation of dye by Fenton process. Application of optimum operation conditions of: Fe2+/Dye = 10 and Fe2+/H2O2= 25 at constant pH=3, mineralization of 78% was achieved for the dye with initial COD value of 1228 mg/L. Based on the degradation effciency , the optimized initial concentration of Fe2+ and H2O2 has a proven influence in treatment of waste water with high COD value by Fenton process

Production of lactic acid and glycolic acid in one-pot electrochemical cell

In recent years, due to the oversupply of glycerol globally, its price has dropped dramatically or become valueless. The aim of this study is to convert glycerol into high value-added compounds such as glycolic acid and lactic acid in one-pot electrochemical cell. The electrochemical process was carried out over platinum (as anode electrode) and activated carbon composite (as cathode electrode), with amberlyst-15 as reaction catalyst. The results obtained have proven that this simple method is applicable to produce glycolic acid and lactic acid in one step electrochemical process with a total product yield above 70 %. Finally, the overview reaction mechanism to the formation of these products was proposed. Please click Additional Files below to see the full abstract

Atmospheric hydrodeoxygenation of bio-oil oxygenated model compounds:A review

Hydrodeoxygenation (HDO) of various bio oil oxygenated model compounds in low H2 pressure has been discussed in this study. Because of the high yield of aromatic mixtures in bio-oil, they carry great potential for fuel efficiency. Nevertheless, due to its high viscosity, abundance of acid, and heteroatom contaminants, the bio-oil ought to be upgraded and hydrotreated in order to be applied as an alternative fuel. A continuous low H2 pressure HDO of bio-oil is favored as it could be simply integrated with conventional pyrolysis systems, functioning at low pressures, as well as supporting a flexible plan for serial processing in respective bio-refineries. Additionally, such a process is cheaper and safer in comparison with the high pressure set ups. This review meticulously elaborates on the operation conditions, challenges, and opportunities for using this process in an industrial scale. The operating temperature, the H2 flow ratio, the active site, and the catalyst stability are some important factors to be considered when it is intended to reach a high conversion efficiency for the HDO in low H2 pressure

Preparation and characterization of activated carbon from Typha orientalis leaves

Background In this study, activated carbon (AC) was prepared from Typha orientalis or commonly known as cattail leaves using physical and chemical activation phosphoric acid (H3PO4), as dehydrating agent. A two-stage process was used, i.e., semi-carbonization stage at 200 °C for 15 min as first stage followed by second stage activation, at 500 °C for 45 min. The precursor material with the impregnated agent was exposed straight away to semi-carbonization and activation temperature using a laboratory scale muffle furnace (Carbolite RHF 1500, England) under static condition in a self-generated atmosphere. Results The best condition in AC production was based on chemical activation which is AC2 with 2 M of H3PO4. AC2 has the highest removal efficiency, 97.4 % in 4 ppm concentration of Pb(II) and percentage yield of 62.73 % could be reached. The pH of the AC was controlled in the range 5–6. From Fourier transform infrared spectroscopy, functional groups such as hydroxyl group, lactone group, and carboxyl group were obtained. These were clearly illustrated by scanning electron microscopy micrographs that porous structure was progressively developed with sponge-like structure. Conclusions The Pb(II) adsorption results were best fitted in the Langmuir isotherm for equilibrium data while the adsorption kinetic fitted to the pseudo-second order model. The maximum Brunauer, Emmett and Teller surface area of the best produced AC was found to be around 1,238 m2/g. The maximum adsorption capacity was found to be 7.95 mg/g