Production of Y and Usy Zeolite for the Active Component of Cracking Catalyst

Standard Y zeolite has been prepared from sodium aluminate as an alumina source and Cab-O-Sil or sodium silicate as a silicate source. This study in particular aimed to obtain a reliable procedure to produce Y zeolite with Si/Al ratio ≥5. The resulted zeolite was then converted into Ultra Stable Y Zeolite (USY) through hydrothermal dealumination at high temperature. The study managed to procure a formulae and procedure to produce a zeolite Y which has SiO2/Al2O3 > 5 and a very stable USY. The procedure succeeded in obtaining synthesized USY that is ready to use as an active phase of cracking catalyst by combining it with other components which are matrix (modified clay and active matrix) and additives (ZSM- 5)

Notes on the Molluscan Fauna of Pulau Pari

Among the soores of islands that make up "Pulau Seribu",Pulau Pari is ecologically interesting. It is composed of five small islands united by a common., distantly located, outer reef.Collectively they offer a long beach line easily within our reach.The vast intertidal area, the uneven bottom topography and the nature of the bottom, give rise to different kind of habitats from which we may expect different biotic populations

Peranan Pendapatan Luar USAhatani Dalam Mengurangi Tekanan Penduduk the Role Off-farm Income to Reduce the Population Pressure

Sempitnya luas lahan USAhatani yang diakibatkan tingkat pertumbuhan penduduk serta bertambah luasnya lahan pertanian untuk kepentingan takpertanian mengakibatkan naiknya tekanan penduduk. Namun, perkembangan keaktifan petani di luar USAhatani membawa konsekuensi turunnya tekanan penduduk atas sumberdaya alam. Tujuan penelitian ini untuk mengetahui: (1) tekanan penduduk baik di tingkat rumah tangga maupun wilayah dan (2) peranan pendapatan luar USAhatani terhadap tekanan penduduk. Penelitian yang dilaksanakan di dua desa di Kabupaten Banyumas dengan Sampel Acak Sederhana dalam memilih petani sampelnya. Hasil penelitian menunjukkan bahwa: (1) nilai tekanan penduduk lebih besar dari satu yang berarti bahwa kebutuhan dasar penduduk di dua desa penelitian belum terpenuhi dan (2) pendapatan luar USAhatani berperan dalam mengurangi tekanan penduduk

Synthesis of NaY Zeolite Using Mixed Calcined Kaolins

Kaolin is one of several types of clay minerals. The most common crystalline phase constituting kaolin minerals is kaolinite, with the chemical composition Al2Si2O5(OH)4. Kaolin is mostly used for manufacturing traditional ceramics and also to synthesize zeolites or molecular sieves. The Si-O and Al-O structures in kaolin are inactive and inert, so activation by calcination is required. This work studies the conversion of kaolin originating from Bangka island in Indonesia into calcined kaolin phase as precursor in NaY zeolite synthesis. In the calcination process, the kaolinite undergoes phase transformations from metakaolin to mullite. The Bangka kaolin is 74.3% crystalline, predominantly composed of kaolinite, and 25.7% amorphous, with an SiO2/Al2O3 mass ratio of 1.64. Thermal characterization using simultaneous DSC/TGA identified an endothermic peak at 527°C and an exothermic peak at 1013°C. Thus, three calcination temperatures (700, 1013, and 1050 °C) were selected to produce calcined kaolins with different phase distributions. The best product, with 87.8% NaY zeolite in the 54.7% crystalline product and an SiO2/Al2O3 molar ratio of 5.35, was obtained through hydrothermal synthesis using mixed calcined kaolins with a composition of K700C : K1013C : K1050C = 10 : 85 : 5 in %-mass, with seed addition, at a temperature of 93 °Cand a reaction time of 15 hours

Synthesis of -Al2O3 Catalyst Support From Kaolin of Indonesian Origin

Kaolin has been identified as a potential raw material for the production of -Al2O3 for hydrotreating catalyst support. This work explores the technical feasibility of applying the potassium hydroxide (KOH) e xtraction synthesis route on kaolin from the Belitung Island in Indonesia. The application of a published synthesis method to Belitung kaolin requires an approximately twofold increase in kaolin calcination time, an increase in kaolin calcination temperature from 950 to 1000 °C, and a tenfold increase in metakaolin extraction time, to obtain a specific surface area higher than 200 m2/g. The highest specific surface area of 233 m2/g was obtained when the kaolin was calcined at 1000 °C for 24 hours, and the metakaolin was extracted by concentrated KOH solution for 12 hours. Phase characterization of the final product confirmed the formation of -Al2O3, but with the inclusion of low-surface area -Al2O3 phase

Dynamic Behavior of Reverse Flow Reactor for Lean Methane Combustion

The stability of reactor operation for catalytic oxidation of lean CH4 has been investigated through modeling and simulation, particularly the influence of switching time and heat extraction on reverse flow reactor (RFR) performance. A mathematical model of the RFR was developed, based on one-dimensional pseudo-homogeneous model for mass and heat balances, incorporating heat loss through the reactor wall. The configuration of the RFR consisted of inert-catalyst-inert, with or without heat extraction that makes it possible to store the energy released by the exothermic reaction of CH4 oxidation. The objective of this study was to investigate the dynamic behavior of the RFR for lean methane oxidation and to find the optimum condition by exploring a stability analysis of the simple reactor. The optimum criteria were defined in terms of CH4 conversion, CH4 slip, and heat accumulation in the RFR. At a switching time of 100 s, the CH4 conversion reached the maximum value, while the CH4 slip attained its minimum value. The RFR could operate autothermally with positive heat accumulation, i.e. 0.02 J/s. The stability of the RFR in terms of heat accumulation was achieved at a switching time of 100 s

Homogeneity of Continuum Model of an Unsteady State Fixed Bed Reactor for Lean CH4 Oxidation

In this study, the homogeneity of the continuum model of a fixed bed reactor operated in steady state and unsteady state systems for lean CH4 oxidation is investigated. The steady-state fixed bed reactor system was operated under once-through direction, while the unsteady-state fixed bed reactor system was operated under flow reversal. The governing equations consisting of mass and energy balances were solved using the FlexPDE software package, version 6. The model selection is indispensable for an effective calculation since the simulation of a reverse flow reactor is time-consuming. The homogeneous and heterogeneous models for steady state operation gave similar conversions and temperature profiles, with a deviation of 0.12 to 0.14%. For reverse flow operation, the deviations of the continuum models of thepseudo-homogeneous and heterogeneous models were in the range of 25-65%. It is suggested that pseudo-homogeneous models can be applied to steady state systems, whereas heterogeneous models have to be applied to unsteady state systems

The Influence of PEG400 and Acetone on Polysulfone Membrane Morphology and Fouling Behaviour

Modification of polysulfone ultrafiltration membrane was conducted by blending polysulfone with PEG400 and acetone as additives. The influence of each additive on the resulted membrane morphology and fouling characteristics were investigated. The experimental results showed that the hydrophilicity of the polysulfone membrane was improved by the increase of PEG400 in the polysulfone membrane. The water contact angle of the membrane was decreased from 76.1° to 38.31° when 35 %wt of PEG400 was added into the polysulfone solution, while the water content of the membrane was increased by around 38%. The high concentration of PEG400 in the polysulfone solution led to the formation of longer finger-like cavities in the membrane structure and resulted in a thicker membrane skin layer. The high concentration of PEG400 also contributed to the increase in hydraulic resistance of the membrane due to organic matter fouling. This problem could be minimized by the addition of acetone into the polysulfone solution, which resulted in a lower fouling resistance of organic matter during up to five hours of peat water filtration

Pengolahan Kulit Kerang Untuk Bahan Baku Kerajinan

Kulit kerang (cangkang) untuk dapat dimanfaatkan sebagai kerajinan perlu diolah terlebih dahulu. Pengolahan ini dimaksudkan untuk menghilangkan kotoran, bau dan menghilangkan lapisan kulit luar agar supaya lapisan kulit mutiara (kulit dalam) bisa nampak. Pengolahan kulit kerang dapat dilakukan dengan cara kimia dan mekanik. Pengolahan kulit kerang cara kimia dilakukan dengan merendam didalam larutan asam klorida atau cuka. Sedangkan cara mekanik dilakukan dengan menggunakan gerinda. Hasil penelitian menunjukkan bahwa pengolahan dengan cara kimia mudah dilaksanakan, waktu lebih singkat (247 menit/4 kg/orang), tidak memerlukan ketrampilan namun menimbulkan limbah cair. Pengolahan dengan cara mekanik memerlukan ketrampilan, waktu lebih lama (425 menit/4 kg/orang), tidak menimbulkan limbah cair tetapi menimbulkan limbah padat