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Dual-Bed Catalytic System for Direct Conversion of Methane to Liquid Hydrocarbons

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Journal of natural Gas Chemistry 2006年第3期15卷 191-202页

作者： N. A. S. Amin Sriraj Ammasi chemical Reaction engineering Group (CREG) Faculty of Chemical and Natural Resources EngineeringUniversiti Teknologi Malaysia81310 UTMSkudaiJohorMalaysia

A dual-bed catalytic system is proposed for the direct conversion of methane to liquid hydrocarbons. In this system, methane is converted in the first stage to oxidative coupling of methane （OCM） products by selective catalytic oxidation with oxygen over La-supported MgO catalyst. The second bed, comprising of the HZSM-5 zeolite catalyst, is used for the oligomerization of OCM light hydrocarbon products to liquid hydrocarbons. The effects of temperature （650-800 ℃）, methane to oxygen ratio （4-10）, and SIO2/Al2O3 ratio of the HZSM-5 zeolite catalyst on the process are studied. At higher reaction temperatures, there is considerable dealumination of HZSM-5, and thus its catalytic performance is reduced. The acidity of HZSM-5 in the second bed is responsible for the oligomerization reaction that leads to the formation of liquid hydrocarbons. The activities of the oligomerization sites were unequivocally affected by the SiO2/Al2O3 ratio. The relation between the acidity and the activity of HZSM-5 is studied by means of TPD-NH3 techniques. The rise in oxygen concentration is not beneficial for the C5＋ selectivity, where the combustion reaction of intermediate hydrocarbon products that leads to the formation of carbon oxide （CO＋CO2） products is more dominant than the oligomerization reaction. The dual-bed catalytic system is highly potential for directly converting methane to liquid fuels.

关键词： dual-bed HZSM-5 oligomerization acidity liquid hydrocarbons

Improved Performance of W/HZSM-5 Catalysts for Dehydroaromatization of Methane

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Journal of natural Gas Chemistry 2004年第3期13卷 148-159页

作者： Nor Aishah Saidina Amin Kusmiyati Department of chemical engineering Faculty of Chemical and Natural Resources EngineeringUniversiti Teknologi Malaysia 81310 UTM Skudai Johor Malaysia.Department of Chemical Engineering Faculty of Chemical and Natural Resources EngineeringUniversiti Teknologi Malaysia 81310 UTM Skudai Johor Malaysia.

The dehydroaramatization of methane over W-supported ZSM-5 with varying degrees of Li+ ion-exchanged catalysts was studied with and without oxygen at 1073 K and atmospheric pressure. Catalyst activity and stability were found to be influenced by the catalyst acidity related to Bronsted acid sites and by the presence of oxygen in the feed. The NH3-TPD and FTIR-pyridine results demonstrated that partially exchanged of H+ ions by Li+ into the W/HZSM-5 catalysts could be used to control the amount of strong acid sites on the catalyst surface. Without oxygen, the 3WHLi-Z (5:1) catalyst that has strong acid sites equal to nearly 74% of the original strong acid sites in the parent HZSM-5 exhibited the highest methane conversion and selectivity towards aromatics. However, the catalyst deactivated in a five hour period. In the presence of oxygen, the catalyst activity and stability could be improved further. The results of this study revealed that a suitable amount of strong Bronsted acid sites as well as oxygen addition in the feed increased the catalyst activity and stability. The 3WHLi-Z(5:1) catalyst exhibited improved performance in the dehydroaromatization of methane.

关键词： dehydroaromatization methane W-supported ZSM-5 partial ion exchange H+ ion Li ion catalyst activity catalyst stability catalyst acidity oxygen presence improved performance

Methane to Liquid Hydrocarbons over Tungsten-ZSM-5 and Tungsten Loaded Cu/ZSM-5 Catalysts

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Journal of natural Gas Chemistry 2006年第4期15卷 340-347页

作者： Didi Dwi Anggoro Nor Aishah Saidina Amin Department of chemical engineering University of Diponegoro TembalangSemarang 50239Indonesia faculty of chemical and natural resources engineering Universiti Teknologi MalaysiaJohor Bahru 81130Malaysia

Metal containing ZSM-5 can produce higher hydrocarbons in methane oxidation. Many researchers have studied the applicability of HZSM-5 and modify ZSM-5 for methane conversion to liquid hydrocarbons, but their research results still lead to low conversion, low selectivity and low heat resistance. The modified HZSM-5, by loading with tungsten （W）, could enhance its heat resistant performance, and the high reaction temperature （800 ℃） did not lead to a loss of the W component by sublimation. The loading of HZSM-5 with tungsten and copper （Cu） resulted in an increment in the methane conversion as well as CO2 and C5＋ selectivities. In contrast, CO, C2-3 and H2O selectivities were reduced. The process of converting methane to liquid hydrocarbons （C5＋） was dependent on the metal surface area and the acidity of the zeolite. High methane conversion and C5＋ selectivity, and low H20 selectivity are obtained over W/3.0Cu/HZSM.

关键词： methane liquid hydrocarbons HZSM-5 W-ZSM-5 W-Cu/ZSM-5

An evaluation of harvesting costs in present and planned operations: case study—Waston District of Mazandaran Wood and Paper Industries

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Journal of Forestry Research 2018年第1期29卷 215-220页

作者： Majid Lotfalian Mohammad Ali Akbari Gorji Seyed Ataollah Hoseini Maryam Kazemi Department of Forestry Faculty of Natural Resources Sari University of Agricultural Sciences and Natural Resources Forestry Master of Science Graduates Faculty of Natural Resources Sari University of Agricultural Sciences and Natural Resources Department of Forestry Faculty of Natural ResourcesTehran University

Amongst all forest utilization phases, harvesting plays a key role as the beginning phase of the utilization cycle and has a significant effect on the following *** this research, in order to examine the reduction of costs with respect to present and planned operations, the starting time of the harvesting or cutting phase and work flow were recorded. The starting time of each phase of the entire operation was recorded as well. Before harvesting the marked tree, the appropriate felling direction was determined and the azimuth of the correct direction was *** results indicate that there was not a meaningful relationship between the differences in direction of a leaning tree compared with the felling direction. However, there was a significant relationship between the difference of the defined and felling direction and the difference in tree leaning and defined direction. The same trend was observed between tree leaning and felling directions and tree leaning and defined directions. On the other hand,there was no significant relationship between tree leaning and felling directions and the defined and tree felling directions. In addition, this research shows that with an increase in tree volume, the time for tree cutting ***, when the difference of tree leaning and felling direction decreased, the time to cut the tree *** regression equation is Y = 168.9–0.14（the difference between tree leaning and felling direction）＋ 0.7（volume）.

关键词： Chainsaw Felling direction Cutting time Tree leaning direction

Tracing suspended and bed sediments during high and low water periods using geochemical characteristics-Case study:Vazrood watershed,northern Iran

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Journal of Mountain Science 2024年第2期21卷 470-483页

作者： KARIMI Nabiyeh GHOLAMI Leila KAVIAN Ataollah KHALEDI DARVISHAN Abdulvahed Department of Watershed Management Faculty of Natural ResourcesSari Agricultural Sciences and Natural Resources UniversitySari ***Iran Department of Watershed Management engineering Faculty of Natural ResourcesTarbiat Modares UniversityNoor ***Iran

Complete and comprehensive information about sediment dynamic and identification of hotspots of sediment production and transport are necessary for understanding the erosion processes and increasing the efficiency of soil and water conservation *** studies used the sediment fingerprint techniques to investigate the contribution of different sources in suspended and bed sediment yield of the ***,the contribution of various land use/land covers in suspended and bed sediment yield for the great Caspian Sea basin is in an aura of ambiguity and the present study was conducted to gather information about an important part of this area in northern Iran,where rangelands are located upstream of Hyrcanian forests and dense agricultural lands are located *** surface soil of different land use/land covers including forest,rangeland,agriculture and streambank lands were sampled in 30 *** and bed sediments were sampled in the watershed outlet in two high and low water *** characteristics of soil and sediment samples containing 59 elements were measured using ICP-OES GBC *** reliable and suitable tracers from 59 elements were then selected using Range test,Kruskal-Wallis and Discriminant Function Analysis,respectively,in FingerPro package of R *** results showed that for suspended sediment,streambank and rangeland had the highest contributions of 86.2%and 47.5%,respectively,in two high and low water *** bed sediment,in two high and low water periods,rangeland and streambank had the highest contributions of 73.8%and 84.4%,*** use change and especially human activities such as agriculture,road construction and development of residential areas along the main river riparian zone has led to a significant increase in suspended and bed sediments.

关键词： Caspian Sea basin FingerPro Geochemistry Sediment transport Tracer combination

Co-Generation of C_2 Hydrocarbons and Synthesis Gases from Methane and Carbon Dioxide: a Thermodynamic Analysis

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Journal of natural Gas Chemistry 2005年第3期14卷 140-150页

作者： Istadi Nor Aishah Saidina Amin chemical Reaction engineering Group (CREG) Faculty of Chemical and Natural Resources Engineering Universiti Teknologi Malaysia UTM Skudai Johor 81310 Malaysia Chemical Reaction Engineering Group (CREG) Faculty of Chemical and Natural Resources Engineering Universiti Teknologi Malaysia UTM Skudai Johor 81310 Malaysia

This paper deals with thermodynamic chemical equilibrium analysis using the method of direct minimization of Gibbs free energy for all possible CH4 and CO2 reactions. The effects of CO2/CH4 feed ratio, reaction temperature, and system pressure on equilibrium composition, conversion, selectivity and yield were studied. In addition, carbon and no carbon formation regions were also considered at various reaction temperatures and CO2/CH4 feed ratios in the reaction system at equilibrium. It was found that the reaction temperature above 1100 K and CO2/CH4 ratio=1 were favourable for synthesis gas production with H2/CO ratio unity, while carbon dioxide oxidative coupling of methane （CO2 OCM） reaction to produce ethane and ethylene is less favourable thermodynamically. Numerical results indicated that the no carbon formation region was at temperatures above 1000 K and CO2/CH4 ratio larger than 1.

关键词： thermodynamic chemical equilibrium co-generation synthesis gas C2 hydrocarbons Gibbs free energy CH4 C02 carbon

Characterization and Activity of Cr, Cu and Ga Modified ZSM-5 for Direct Conversion of Methane to Liquid Hydrocarbons

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Journal of natural Gas Chemistry 2003年第2期12卷 123-134页

作者： Nor Aishah Saidina Amin Didi Dwi Anggoro faculty of chemical and natural resources engineering Universiti Teknologi Malaysia 81130 Skudai Johor MalaysiaFaculty of Chemical and Natural Resources Engineering Universiti Teknologi Malaysia 81130 Skudai Johor Malaysia 2 Department of chemical engineering University of Diponegoro 23589 Semarang Indonesia

Direct conversion of methane using a metal-loaded ZSM-5 zeolite prepared viaacidic ion exchange was investigated to elucidate the roles of metal and acidity in the formation ofliquid hydrocarbons. ZSM-5 (SiO_2/Al_2O_3=30) was loaded with different metals (Cr, Cu and Ga)according to the acidic ion-exchange method to produce metal-loaded ZSM-5 zeolite catalysts. XRD,NMR, FT-IR and N_2 adsorption analyses indicated that Cr and Ga species managed to occupy thealuminum positions in the ZSM-5 framework. In addition, Cr species were deposited in the pores ofthe structure. However, Cu oxides were deposited on the surface and in the mesopores of the ZSM-5zeolite. An acidity study using TPD-NH_3, FT-IR, and IR-pyridine analyses revealed that the totalnumber of acid sites and the strengths of the Broensted and Lewis acid sites were significantlydifferent after the acidic ion exchange treatment. Cu loaded HZSM-5 is a potential catalyst fordirect conversion of methane to liquid hydrocarbons. The successful production of gasoline via thedirect conversion of methane depends on the amount of aluminum in the zeolite framework and thestrength of the Broensted acid sites.

关键词： characterization activity modified ZSM-5 methane direct conversion liquid hydrocarbons

Spatio-temporal suspended sediment fingerprinting under different land management practices

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International Journal of Sediment Research 2023年第4期38卷 481-493页

作者： Maziar Mohammadi Abdulvahed Khaledi Darvishan Nader Bahramifar Seyed Jalil Alavi Department of Watershed Management engineering Faculty of Natural Resources Tarbiat Modares University Department of Geography University of Zurich Department of Environmental Science Faculty of Natural Resources Tarbiat Modares University Department of Forestry Faculty of Natural Resources Tarbiat Modares University

Understanding spatio-temporal suspended sediment dynamics is more important in large watersheds due to the decisive role of local source apportionment in sediment transport and yield. The Talar River with a large mountainous watershed in northern Iran, which plays a vital role in water supply for agriculture and drinking, recently has faced quality degradation. The current study explores the relative contribution of suspended sediment sources using geochemical tracers and fingerprinting techniques in high and low flow periods along this river. Soil samples were collected from four major land uses including rangeland, forest, rainfed agriculture, and irrigated agriculture, as well as riverbanks and riparian zones along the main river. Furthermore, suspended sediment was sampled at four sampling points along the main river in two seasons. Land use apportionment in suspended sediment yield was calculated using an unmixing model included in a newly developed package(Finger Pro) in high flow and low flow, separately. The fingerprinting results showed a highly spatio-temporal dynamic for sediment source contribution along the main river in high and low flow periods. natural land uses(forest and rangeland) in upstream reaches and agricultural land uses and riverbank sources in downstream reaches showed higher contributions to suspended sediment yield. The mean contribution of various land uses for both high and low flow periods indicated substantial contributions from forest(34%-41%) and riverbanks(31%-33%). The significant difference in sediment geochemical properties for the two flow seasons highlights the important role of the prevailing climatic-hydrologic condition on river ***, this issue indicates that sediment source contributions and transfer mechanisms are highly dynamic in Talar River watershed. The current study outcomes provide essential knowledge to create a robust strategy for mitigation of river sediment pollution.

关键词： Land use River water quality Sediment fingerprinting Sustainability Unmixing model

Removal of antibiotics in a parallel-plate thin-film-photocatalytic reactor: Process modeling and evolution of transformation by-products and toxicity

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Journal of Environmental Sciences 2017年第10期29卷 114-122页

作者： Can Burak?zkal Zacharias Frontistis Maria Antonopoulou Ioannis Konstantinou Dionissios Mantzavinos Süreyya Meric Environmental engineering Namik Kemal University Faculty of Engineering Department of chemical engineering University of Patras Department of Environmental&natural resources Management University of Patras Department of Chemistry University of Ioannina

Photocatalytic degradation of sulfamethoxazole（SMX） antibiotic has been studied under recycling batch and homogeneous flow conditions in a thin-film coated immobilized system namely parallel-plate（PPL） reactor. Experimentally designed, statistically evaluated with a factorial design（FD） approach with intent to provide a mathematical model takes into account the parameters influencing process performance. Initial antibiotic concentration, UV energy level, irradiated surface area, water matrix（ultrapure and secondary treated wastewater） and time, were defined as model parameters. A full of 2~5 experimental design was consisted of 32 random experiments. PPL reactor test experiments were carried out in order to set boundary levels for hydraulic, volumetric and defined defined process parameters. TTIP based thin-film with polyethylene glycol ＋ TiO2 additives were fabricated according to pre-described methodology. Antibiotic degradation was monitored by High Performance Liquid Chromatography analysis while the degradation products were specified by LC–TOF-MS analysis. Acute toxicity of untreated and treated SMX solutions was tested by standard Daphnia magna method. Based on the obtained mathematical model, the response of the immobilized PC system is described with a polynomial equation. The statistically significant positive effects are initial SMX concentration,process time and the combined effect of both, while combined effect of water matrix and irradiated surface area displays an adverse effect on the rate of antibiotic degradation by photocatalytic oxidation. Process efficiency and the validity of the acquired mathematical model was also verified for levofloxacin and cefaclor antibiotics. Immobilized PC degradation in PPL reactor configuration was found capable of providing reduced effluent toxicity by simultaneous degradation of SMX parent compound and TBPs.

关键词： Thin-film photocatalysis Sulfamethoxazole (SMX) Levofloxacin (LVX) Cefaclor (CFL) Factorial design Modeling Parallel-plate reactor