Synthesis of Light Hydrocarbons via Oxidative Coupling of Methane over Silica-supported Na2WO4-TiO2 Catalyst

Methane is of great interest for conversion into high-value hydrocarbons (C2+) and olefins, via oxidative coupling of methane (OCM) using catalysts. In this work, Na2WO4-TiO2/SiO2 catalyst, along with the single catalysts of its components (Na2WO4/SiO2 and TiO2/SiO2), was investigated for OCM reaction to C2+. We found that 5 wt% Na2WO4+ 5 wt% TiO2 on the SiO2 support was a superior catalyst for OCM reaction compared to the single catalysts. The maximum C2+ formation of the Na2WO4-TiO2/SiO2 catalyst was found under test conditions of a N2/(4CH4:1O2) feed gas ratio of 1:1, a reactor temperature of 700 ºC, and gas hourly space velocity of 9,500 h−1, exhibiting 71.7% C2+ selectivity, 6.8% CH4 conversion, and 4.9% C2+ yield. Moreover, the activity of the catalyst had good stability over 24 h of on-stream testing. The characterizations of the Na2WO4-TiO2/SiO2 catalyst using XRD, FT-IR, XPS, FE-SEM, and TEM revealed that a crystalline structure of α-cristobalite of SiO2 was present along with TiO2 crystals, substantially enhancing the activity of the catalyst for OCM reaction to C2+

Green Diesel Production from Oleic Acid Deoxygenation Using Subcritical Water under Hydrogen-Free Condition

Green diesel or bio-hydrogenated diesel (BHD) is a second generation renewable liquid fuel that can be produced from several types of renewable sources such as triglyceride in vegetable oils or animal fats, free fatty acid in waste from refining palm oil industry, and their derivatives via a catalytic reaction involving hydrogenation and deoxygenation provided n-alkanes as a main product. In this work, the aim was to investigate the effect of reaction time and catalyst type on green diesel production in a batch mode without H2 feed. The green diesel was produced from oleic acid using activated carbon and commercial catalyst at reaction temperature of 250 °C and total pressure of 40 bars under DI water as a hydrogen source. The results showed that 100% oleic acid conversion was obtained by using both type of catalysts. Pentadecane was the main product with 96% percentage at 3 h reaction time for commercial catalyst and 100% percentage at 5 h reaction time for activated carbon. In addition, the products in gas phase were CO2 and CO for both types of catalyst and CH4 only appeared when commercial catalysts were used.&nbsp

Influence of drying technique on physicochemical properties of bimodal meso-macropore structure of silica support

[EN] Drying process directly affect in structure of the silica support for catalysts. Therefore, we herein prepared bimodal meso-macropore structure of silica by sol-gel method and investigated the silica support obtained from various drying techniques, namely, hot air drying (HA), microwave drying(MW)and freeze drying (FD)by means of BET and BJH N2-sorption, and SEM. The results showed a significant effect of drying technique on the textural properties of the dried bimodal porous silica support. In addition, it was found that freeze drying could enhance surface area of silica support with higher than 500 m2/g.The authors express their sincere appreciation to the Kasetsart University Research and Development Institute (KURDI) and the Center of Excellence on Petrochemical and Materials Technology, National Science and Technology Development Agency ( NSTDA) for supporting the study financially.Panchan, N.; Niamnuy, C.; Chukeaw, T.; Seubsai, A.; Devahastin, S.; Chareonpanich, M. (2018). Influence of drying technique on physicochemical properties of bimodal meso-macropore structure of silica support. En IDS 2018. 21st International Drying Symposium Proceedings. Editorial Universitat Politècnica de València. 1935-1942. https://doi.org/10.4995/IDS2018.2018.8369OCS1935194

High Throughput Synthesis and Screening of New Catalytic Materials for the Direct Epoxidation of Propylene

Nanoparticles of 35 individual metals as well as their binary combinations were synthesized using High Throughput pulsed laser ablation (PLA), and collected on Al2O3, CeO2, SiO2, TiO2, and ZrO2 pellets. These materials were then screened for their catalytic activities and selectivities for the partial oxidation of propylene, in particular for propylene oxide (PO), using array channel microreactors. Reaction conditions were the following: 1 atm pressure, gas hourly space velocity (GHSV) of 20,000 h(-1), temperature 300 degrees C, 333 degrees C, and 367 degrees C, and feed gas composition 20 vol% O-2, 20 vol% C3H6 and balance He. Initial screening experiments resulted in the discovery of SiO2 supported Cr, Mn, Cu, Ru, Pd, Ag, Sn, and Ir as the most promising leads for PO synthesis. Subsequent experiments pointed to bimetallic Cu-on-Mn/SiO2, for which the PO yields increased several fold over single metal catalysts. For multimetallic materials, the sequence of deposition of the active metals was shown to have a significant effect on the resulting catalytic activity and selectivity

New Catalytic Materials for the Direct Epoxidation of Propylene by Oxygen: Application of High-Throughput Pulsed Laser Ablation

New catalytic materials were prepared by depositing nanoparticles of 35 different metals as well as their select binary combinations on Al2O3, CeO2, SiO2, TiO2, and ZrO2 supports. Nanoparticles were synthesized by high-throughput pulsed laser ablation (PLA). Catalytic materials were then screened for their selectivities towards the synthesis propylene oxide (PO) from propylene and oxygen using array channel microreactors at 1 atm and 300, 333, and 367 A degrees C. A gas hourly space velocity (GHSV) of 20,000 h(-1) was used at the feed gas composition of 20% O-2, 20% C3H6 and the balance He. Initial screening experiments resulted in the discovery of SiO2 supported Cr, Mn, Cu, Ru, Pd, Ag, Sn, and Ir as the most promising leads for PO synthesis. Subsequent experiments pointed to bimetallic Cu-on-Mn/SiO2, for which the PO yields increased several fold over single metal catalysts. For multimetallic materials, the sequence of deposition of the active metals was shown to have a significant effect on the resulting catalytic activity and selectivity

Chromium-Ruthenium Oxides Supported on Gamma-Alumina as an Alternative Catalyst for Partial Combustion of Methane

Catalyst screening of γ-Al2O3-supported, single-metal and bimetallic catalysts revealed several bimetallic catalysts with activities for partial combustion of methane greater than a benchmark Pt/γ-Al2O3 catalyst. A cost analysis of those catalysts identified that the (2 wt%Cr + 3 wt% Ru)/γ-Al2O3 catalyst, denoted as 2Cr3Ru/Al2O3, was about 17.6 times cheaper than the benchmark catalyst and achieved a methane conversion of 10.50% or 1.6 times higher than the benchmark catalyst based on identical catalyst weights. In addition, various catalyst characterization techniques were performed to determine the physicochemical properties of the catalysts, revealing that the particle size of RuO2 became smaller and the binding energy of Ru 3d also shifted toward a lower energy. Moreover, the operating conditions (reactor temperature and O2/CH4 ratio), stability, and reusability of the 2Cr3Ru/Al2O3 catalyst were investigated. The stability test of the catalyst over 24 h was very good, without any signs of coke deposition. The reusability of the catalyst for five cycles (6 h for each cycle) was noticeably excellent

Lead Ions Removal Using Pineapple Leaf-Based Modified Celluloses

Pineapple leaves are largely discarded in the harvest area and considered as agricultural waste. Herein, the extracted pineapple leaves fiber was altered with chelating agents to become an adsorbent for lead ions (Pb2+) removal from aqueous solutions. The initial investigation determined that the most appropriate conditions for extracting cellulose fiber from pineapple leaves were stirring at 90–100 °C in 10%w/v NaOH for 1 h. Next, carboxymethyl, amide, and amidoxime were used to modify with the extracted cellulose fiber, denoted as Cell-CMC, Cell-AM, and Cell-AMX, respectively. At pH 6, Cell-CMC, Cell-AM, Cell-AMX, and the extracted cellulose fiber had maximum adsorption potential values of 9.3, 1.5, 3.6, and 6.3 mg g–1, respectively. In the kinetic analysis, Cell-CMC, Cell-AM, and extracted cellulose adsorption behaviors were well represented using a model of pseudo 1st order, while the adsorption behavior of Cell-AMX was best represented using a model of pseudo 2nd order. Further investigation demonstrated that the desorption efficiency of each adsorbent increased as the pH value was lowered from 3, 4, and 6