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"Numerical modelling of hydrogen production by means of methanol decomposition in a thermocatalytic reactor using corrugated foil made of the Ni3Al intermetallic phase is shown in the paper. Experimental results of the flow analysis of mixtures containing helium and methanol in a thermocatalytic reactor with microchannels were used for the initial calibration of the CFD calculations (calculations based on the Computational Fluid Dynamics method). The reaction of the thermocatalytic methanol decomposition was modelled based on experimental data, considering the size of the active surface. The drop in the methanol concentration at the inlet to the reactor, ten millimetres in front of the thermocatalytic region, is associated with the diffusion of streams of other components, mainly hydrogen and carbon monoxide. The commercial CFD code was expanded by User Defined Functions (UDFs) to include surface chemical reaction rates in the interphase between the fluid and the solid. Extrapolation of data by means of the implemented numerical model enabled the assessment of the minimum length of microreactor channels and prediction of the optimal dimension at the system outlet. The results obtained by means of numerical calculations were calibrated and compared with the experimental data, confirming a satisfactory consistency of the data"

"Objectives of this research are mainly to study impacts of acidity strength (by varying amount of precipitant and loading Al-Si) and the effect of nickel particle size (by varying calcinations temperature) on decomposition reaction performances. In this research, high-nickel-loaded catalyst is prepared with two methods. Ni-Cu/Al catalysts were prepared with co-precipitation method. While the Ni-Cu/Al-Si catalyst were prepared by combined co-precipitation and sol-gel method. The direct cracking of methane was performed in 8mm quartz fixed bed reactor at atmospheric pressure and 500-700°C. The main results showed that the Al content of catalyst increases with the increasing amount of precipitant. The activity of catalyst increases with the increasing of catalyst?s acidity to the best possible point, and then increasing of acidity will reduce the activity of catalyst. Ni-Cu/4Al and Ni-Cu/11Al deactivated in a very short time hence produced fewer amount of nanocarbon, while Ni-Cu/15Al was active in a very long period. The most effective catalyst is Ni-Cu/22Al, which produced the biggest amount of nanocarbon (4.15 g C/g catalyst). Ni catalyst diameter has significant effect on reaction performances mainly methane conversion and product yield. A small Ni crystal size gave a high methane conversion, a fast deactivation and a low carbon yield. Large Ni particle diameter yielded a slow decomposition and low methane conversion. The highest methane conversion was produced by catalyst diameter of 4 nm and maximum yield of carbon of 4.08 g C/ g catalyst was achieved by 15.5 nm diameter of Ni catalyst."

"Produksi hidrogen dengan menggunakan metanol atau gliserol sebagai elektron donor pada fotokatalis TiO2, TiNT, Pt/TiO2 dan Pt/TiNT pada suhu reaksi dari 30 oC sampai dengan 70 oC telah diteliti. Metanol dan gliserol efektif sebagai elektron donor untuk produksi hidrogen secara fotokatalisis. Penggunaan metanol lebih unggul 10% dari gliserol pada semua katalis dalam total produksi hidrogen. Produksi hidrogen terbaik ditunjukkan oleh fotokatalis Pt(1%)/TiNT dengan metanol sebagai elektron donor, yaitu sebesar 2306 µmol/gcat, sementara total hidrogen dengan gliserol sebesar 2120 µmol/gcat. Penggunaan dopan Pt pada fotokatalis menghasilkan produksi hidrogen dua kali lebih besar dibandingkan dengan tanpa dopan.

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Hidrogen production with methanol or glycerol as sacrificial agent using TiO2, TiO2 Nanotubes, Pt/TiO2 and Pt/TiO2 Nanotubes photocatalysts at reaction temperature 30 oC to 70 oC have been investigated. Methanol and glycerol were effective for hydrogen production and the best result was methanol with Pt(1%)/TiO2 that have 2306 µmol/gcat, meanwhile with glycerol only produce 2120 µmol/gcat. The other photocatalyst also have the same pattern, which metanol give 10% higher result on total hydrogen production. Catalyst with Pt give twice higher hydrogen production rather than with no Pt."

"Flex matala biofilter dengan luas permukaan 365 m2/m3 (M365) dan 190 m2/m3 (M190) digunakan sebagai carrier bkteri dalam produksi biohidrogen menggunakan reaktor CSTR. Reaktor CSTR yang dilengkapi dengan biofilter (CSTR-PBF) didesain dan dioperasikan untuk memproduksi gas biohidrogen dengan bahan baku limbah pabrik minuman sebagai substrat pada konsentrasi 10 ? 30 g total glukosa/L dan waktu tinggal 8 jam ? 0,5 jam. Carrier atau biofilter dipasang pada bagian tengah fermentor (60 mm dari dasar fermentor) yang berfungsi untuk menghindari washout. Hasil menunjukkan bahwa konsentrasi substrat 15 ? 20 g/L memberikan yield dan Laju produksi gas biohidrogen (LPH) yang tinggi. Biofilter M365 memberikan kinerja produksi hidrogen yang lebih baik dibanding dengan biofilter M190. HRT 0,5 jam memberikan LPH yang paling tinggi, yakni 124,87 L H2/L/hari, namun yieldnya 1,17 mol H2/mol glukosa. Di sisi lain, kondisi yang memberikan yield tertinggi dicapai pada waktu tinggal 4 jam dengan LPH sebesar 13,74 L H2/L/hari dan yield sebesar 1,82 mol H2/mol glukosa. Kondisi operasi yang direkomendasikan adalah waktu tinggal 1 jam dan konsentrasi substrat 20 g glukosa/L dengan LPH 88,69 L H2/L/hari, konversi substrat, 91,85 % dan yield 1,42 mol H2/mol glukosa. Pada waktu tinggal yang rendah, yakni 1 jam dan 0,5 jam terdapat perbedaan distribusi konsentrasi biomassa pada bagian atas, tengah dan bawah reaktor. Produk cair terbesar adalah asam butirat dan asam asetat dengan rasio 1,41 mol asam butirat/mol asam asetat sampai dengan 5,66 mol asam butirat/mol asam asetat.

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A flex-matala packed biofilter with specific surface area M365 m2/m3 (M365) and 190 m2/m3 (M190) were used as a bacteria carrier in a Continuous Stirred Tank Reactor (CSTR) in this study. The continuous stirred tank reactor with packed biofilter (CSTR-PBF) was designed and operated under sugary wastewater substrate at concentration of 10 g total sugar/L ? 30 g total glukosa/L and hydraulic retention time (HRT) 8 h - 0.5 h to assess the biohydrogen producing ability. Biofilter was installed at 60 mm height from the bottom of bioreactor (middle of the bioreactor). The biofilter played a role in avoiding biomass washout. It was found that substrat concentration of 15 ? 20 g glucose/L lead the hydrogen production performa. Biofilter M365 produced the higher hydrogen production rate and yield. The condition producing the higher hydrogen production rate was at HRT 0.5 h with hydrogen production rate (HPR) of 124.87L H2/L/d, and yield of 1.17 mol H2/mol glucose. On the other hand, the condition producing the higher yield obtained when the fermentor operated at HRT 4 h, which hydrogen production rate and yield were 13.74 H2/L/d, and yield of 1.42 mol H2/mol glucose. Operation condition suggested for hydrogen production was HRT 1 h and 20 g total glucose/L which HPR, susbtrate conversion and yield were 88.69 H2/L/d; 91.85 % and 1.42 mol H2/mol glucose. There was difference distribution of biomassa on top, middle and bottom part of the bioreactor observed at HRT 1 h to 0,5 h. Butyric acid and acetic acid were the main liquid product that the ratio was 5.66 mol butyric/mol acetic. A flex packed biofilter used in CSTR system is a better approach to accumulate biomass concentration in bioreactor for enhancing biohydrogen production rate comparison with other kinds of bioreactor."

"ABSTRAKGas hidrogen banyak diperoleh dari proses elektrolisis yang memerlukan energi listrikyang besar. Elektrolisis plasma adalah teknologi baru dalam meningkatkan produktifitashidrogen sekaligus menekan kebutuhan listrik. Penelitian ini dilakukan untuk mengujiefektivitas proses elektrolisis plasma dengan penambahan aditif (larutan metanol danetanol) yang dinyatakan sebagai jumlah produk hidrogen per satuan energi listrik yangdikonsumsi dengan memvariasikan temperatur, tegangan listrik dan konsentrasi larutanKOH. Efektivitas proses ini dibandingkan dengan efektivitas elektrolisis Faraday danelektrolisis plasma tanpa penambahan aditif. Hasil percobaan menunjukkan kenaikankonsentrasi KOH dan tegangan listrik menyebabkan kenaikan jumlah produk hidrogen.Proses elektrolisis plasma pada penelitian ini dapat meningkatkan efektivitas proseshingga 5 kali lipat lebih tinggi dibandingkan dengan elektrolisis plasma tanpapenambahan aditif.

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ABSTRACTHydrogen is commonly produced by electrolysis which consumes a great deal of energy.Plasma electrolysis is a new technology that can increases hydrogen productivity whilelowering electrical energy needs. This research aimed to test the effectiveness of theplasma electrolysis process with methanol and ethanol addition which is expressed as thenumber of products of hydrogen per unit of electrical energy consumed by investigatedtemperature, electrical voltage and the concentration of KOH solution. Then, theeffectiveness of this process compared with the effectiveness of electrolysis Faraday.Results showed an increase of KOH concentration and the voltage causes an increase inthe hydrogen product. Plasma electrolysis process in this research can improve theeffectiveness of processes to 5 fold higher compared plasma electrolysis withoutmethanol and ethanol addition."

"Bintang diklasifikasikan berdasarkan luminositas dan temperatur. Ketika inti panas bintang yang memancarkan energi dengan spektrum kontinu dilewatkan pada gas yang lebih dingin di atmosfer, gas tersebut akan menyerap cahaya tersebut pada panjang gelombang tertentu. Akibatnya, diperoleh spektrum kontinu yang diselang-seling garis serapan. Kuat garis serapan dari unsur yang diamati berbeda pada setiap kelas spektrum. Pengamatan kali ini tentang spektroskopi resolusi tinggi terhadap berbagai kelas spektrum bintang. Selanjutnya didapat spektrum pengamatan unsur Hidrogen yang dianalisis berdasarkan pengaruh pelebaran Doppler. Dalam tugas akhir ini analisis dilakukan untuk menentukan pengaruh pelebaran Doppler terhadap kelimpahan Hidrogen dari sampel bintang-bintang deret utama (kelas V) yang ada dalam rentang kelas menurut katalog Henry Draper. Untuk bintang kelas O yang memiliki nilai temperatur tertinggi,nilai adalah 1:02311 1008 . Dan untuk bintang kelas K yang memiliki nilai temperatur terendah, nilai adalah 3:61362 10 09. Dari nilai untuk masing-masing sampel bintang, dapat dilihat perubahan evolusi bintang darimasing-masing kelas spektrum."

"This book addresses the direct imaging of hydrogen-bond dynamics within water-based model systems assembled on a metal surface, using a scanning tunneling microscope (STM). The dynamics of individual hydrogen bonds in water clusters, hydroxyl clusters, and water-hydroxyl complexes are investigated in conjunction with density functional theory. In these model systems, quantum dynamics of hydrogen bonds, such as tunneling and zero-point nuclear motion, are observed in real space. Most notably, hydrogen atom relay reactions, which are frequently invoked across many fields of chemistry, are visualized and controlled by STM. This work presents a means of studying hydrogen-bond dynamics at the single-molecule level, providing an important contribution to wide fields beyond surface chemistry."

"Produksi hidrogen menggunakan proses elektrolisis plasma sangat potensial untuk dikembangkan karena dapat menjadi alternatif yang praktis demi memenuhi kebutuhan sumber energi. Elektrolisis plasma dapat meningkatkan laju produksi dan efisiensi energi elektrolisis Faraday. Modifikasi reaktor kompartemen ganda dilakukan untuk mencapai kondisi proses pada tegangan listrik yang tinggi namun menekan arus yang mengalir pada sistem sehingga konsumsi energi menjadi rendah. Penelitian ini dilakukan untuk melihat pengaruh tegangan, konsentrasi KOH, penambahan aditif etanol, kedalaman katoda, dan suhu operasi terhadap laju produksi, konsumsi energi, dan efisiensi proses. Produksi hidrogen terbaik diperoleh sebesar 26,50 mmol/menit dengan konsumsi energi sebesar 1,71 kJ/mmol H2. Peningkatan efisiensi terhadap proses elektrolisis mencapai 90 kali lebih besar.

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Hydrogen production by plasma electrolysis is potential to be developed for fulfilling alternative energy needs. Plasma Electrolysis can increase the rate of production and energy efficiency of electrolysis. Double compartment modification reactor is designed to achieve the high electrical voltage and reduce the energy consumption. This research was carried for determining the effect of voltage, KOH concentration, addition of ethanol and temperature in hydrogen production, energy consumption, and process efficiency.The highest hydrogen production obtained is 26,50 mmol / min with 1,71 kJ / mmol H2. This experiment can reach up 90 times hydrogen production compared to electrolysis process."

"Hidrogen merupakan senyawa penting yang digunakan pada kilang minyak bumi terutama untuk menghasilkan produk dengan pengotor yang rendah dan kestabilan yang bagus. Hidrogen umumnya diproduksi oleh hydrogen plant melalui jalur steam reforming – shift converter – CO2 removal. Pada Major Turn Around (TA) yang dilakukan setiap 5 (lima) tahun sekali, penulis diberikan tugas oleh General Manager suatu kilang untuk menjadi Leader pada proyek ini, yang bertanggungjawab dalam proses penggantian katalis di unit Hydrogen Plant. Perbedaan material dan karakteristik pada tiap katalis, serta perbedaan desain reaktor menjadi tantangan tersendiri dalam melaksanakan penggantian katalis. Meskipun demikian, laporan ini berfokus pada upaya perbaikan proses reduksi katalis Low Temperature Shift Converter (LTSC) supaya memperoleh proses reduksi yang stabil dan minim gangguan. Beberapa kendala berdasarkan pengalaman pada proses reduksi sebelumnya berhasil diidentifikasi dan menghasilkan beberapa alternatif solusi antara lain: (a) once-through menggunakan gas alam, (b) recycle menggunakan nitrogen dan dedicated facility, serta (c) recycle menggunakan hidrogen eksternal sebagai gas pereduksi. Alternatif solusi (c) dipilih berdasarkan aspek efektivitas, biaya, dan dampak lingkungan. Penggunaan hidrogen eksternal berhasil memperbaiki proses reduksi menjadi lebih stabil dan minim gangguan yang dapat dilihat dari profil temperatur bed katalis dan tidak terjadinya temperature runaway. Selain itu, durasi reduksi dapat dipangkas dari sebelumnya 6 hari menjadi 3 hari. Dalam menjalankan praktik keinsinyuran tersebut, penulis berpedoman pada peraturan perusahaan antara lain: Tata Kerja Organisasi Penyusunan Hazard Identification & Risk Assessment (No. B07-012), Pedoman pemilihan jenis dan pengadaan katalis untuk kilang (No. A-002), Tata Kerja Penggunaan Alat untuk pelaksanaan unloading dan loading katalis LTSC (No. D04-31), dan Tata Kerja Penggunaan Alat untuk pelaksanaan reduksi katalis LTSC (No. D04-027).

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Hydrogen is an important substance used in petroleum refineries, especially to produce products with low impurities and good stability. Hydrogen is generally produced by hydrogen plants through steam reforming – shift converter – CO2 removal pathways. On the Major Turn Around (TA) which is carried out every 5 (five) years, the author is given the task by General Manager of a refinery to become Leader of this project which is responsible for the catalyst replacement process in Hydrogen Plant unit. Differences in materials and characteristics of each catalyst, as well as differences in reactor design, become challenges in implementing catalyst replacement. However, this report focuses on efforts to improve the Low Temperature Shift Converter (LTSC) catalyst reduction process, in order to obtain a stable reduction process with minimal disruption. Several obstacles based on experience in previous reduction processes were identified and resulted in several alternative solutions, including: (a) once-through using natural gas, (b) recycling using nitrogen and a dedicated facility, and (c) recycling using external hydrogen as a reducing gas. Alternative solution (c) is selected based on aspects of effectiveness, cost, and environmental impact. The use of external hydrogen succeeded in improving the reduction process to be more stable and with minimal disturbance which can be seen from the temperature profile of the catalyst bed and the absence of temperature runaway. In addition, the reduction duration can be cut from the previous 6 days to 3 days. The author is guided by company regulations in carrying out these engineering practices, including: Work Procedures for preparation of hazard identification & risk assessment (No. B07-012), Guidelines for selecting the type and procurement of catalysts for refineries (No. A-002), Work Procedures for carrying out unloading and loading of LTSC catalysts (No. D04-31), and Procedure for carrying out LTSC catalyst reduction (No. D04-027)."

"Siklopentanon merupakan senyawa yang dapat dikonversi menjadi siklopentana, untuk digunakan sebagai prekursor jet fuel, agar dapat mengurangi titik beku bahan bakar pesawat. Siklopentanon dapat dihasilkan dari reaksi katalitik hidrogenasi berbahan dasar furfural. Namun pengaplikasian reaksi hidrogenasi ini memiliki kekurangan karena tekanan hidrogen yang dibutuhkan sangat tinggi, hingga 80 bar, sehingga memerlukan biaya yang mahal. Karena keterbatasan tingkat kelarutan gas hidrogen dalam cairan, maka pada umumnya, untuk mendapatkan angka konversi dan yield produk yang tinggi, reaksi diberikan tekanan gas hidrogen yang setinggi mungkin. Namun, tingginya tekanan tersebut menjadi tidak efisien jika ditinjau dari segi ekonomi dan safety. Cara untuk mengurangi tekanan yang tinggi tersebut dapat dilakukan dengan melakukan reduksi parsial pada inti aktif katalis dan penggunaan self-inducing impeller. Penelitian ini dilakukan dengan tiga variasi rasio Ni-NiO dan dua variasi tekanan yang berbeda. Katalis Ni-NiO/ZrO2-Re450 dengan struktur heterojunction Ni-NiO (Ni 75,2% dan NiO 24,8%), dan tekanan reaksi 10 bar mampu menghasilkan konversi umpan furfural terbanyak (80,16%), yield siklopentanon terbanyak (58,82%), dan selektivitas siklopentanon tertinggi (73,38%). Hasil kuantitatif tersebut dikaitkan dengan tingkat solubilitas gas hidrogen pada fase liquid yang tinggi, luas permukaan katalis yang besar, komposisi logam nikel yang kecil, interaksi yang kuat antara ini aktif dan penyangga katalis, serta tingkat kebasaan katalis yang kecil.

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Cyclopentanone is a compound that can be converted into cyclopentane to be used as jet fuel precursor to reduce freezing point of aircraft fuel. Cyclopentanone produced from the catalytic reaction of furfural hydrogenation. Applying hydrogenation reaction has drawbacks because the high required hydrogen pressure, up to 80 bar. Due to the limited solubility of hydrogen gas in liquids, the reaction is given the highest pressure possible to obtain high conversion and product yields. However, the high pressure becomes inefficient from an economic and safety point of view. The high pressure can be reduced by converting partial reduction of the catalyst active core and using a self-inducing impeller. This research was conducted with three variations of the Ni-NiO ratio and two different pressure. The Ni-NiO/ZrO2-Re450 catalyst with a Ni-NiO heterojunction structure (75.2% NiO; 24.8% NiO), and a reaction pressure of 10 bar was able to produce the highest furfural conversion (80.16%), cyclopentanone yield (58.82%), and cyclopentanone selectivity (73.38%). These quantitative results are attributed to the high solubility of hydrogen gas in the liquid phase, the large catalyst surface area, the small composition of nickel metal, the strong interaction between active and catalyst support, and the low alkalinity of the catalyst."