Tjokorde Walmiki Samadhi
Chemical Engineering Program, Bandung Institute of Technology, Jalan Ganesha 10 Bandung 40132, Indonesia

Published : 5 Documents

Found 5 Documents

Miscibility Development Computation in Enhanced Oil Recovery by Flare Gas Flooding

Journal of Engineering and Technological Sciences Vol 44, No 3 (2012)
Publisher : ITB Journal Publisher, LPPM ITB

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The use of flare gas as injection gas in miscible gas flooding enhanced oil  recovery  (MGF-EOR)  presents  a  potential  synergy  between  oil  production improvement  and  greenhouse  gases  emission  mitigation.  This  work  is  a preliminary evaluation of the feasibility of miscible flare gas injection based on phase behavior computations of  a model oil (43% n-C5H12 : 57% n-C16H34) and a model flare gas (91% CH4  : 9% C2H6). The computations employed the multiple mixing-cell  model  with  Peng-Robinson  and  PC-SAFT  equations  of  state,  and compared the minimum miscibility pressure (MMP) value in the cases of flare gas  injection  and  CO2  injection.  For  CO2  injection,  both  equations  of  state produced  MMP  values  close  to  the  measured  value  of  10.55  MPa.  Flare  gas injection MMP values were predicted to be 3.6-4.5 times those of CO2  injection. This very high MMP implies high gas compression costs, and may compromise the  integrity  of  the  reservoir.  Subsequent  studies  shall  explore  the  gas -oil miscibility  behavior  of  mixtures  of  flare  gas  with  intermediate  hydrocarbon gases and  CO2,  in  order to  identify  a suitable approach for rendering flare  gas feasible as an injection gas in MGF-EOR.


REAKTOR Volume 15 No.4 Oktober 2015
Publisher : Dept. of Chemical Engineering, Diponegoro University

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STUDY OF SPRAY DRYING PROCESS FOR THE PRODUCTION OF PETROLEUM CRACKING CATALYST. Catalyst for the hydrocarbon fluid catalytic cracking (FCC) process consists of zeolite, matrix, fillers, and binders. The FCC catalyst has a microsphere form (10-120 µm), and can be produced by spray drying. Operating conditions of spray drying affect the characteristics of the microspheres FCC catalyst. The composition slurry (24% by weight) is 27% (by weight) of zeolite NaY, 33% (by weight) of Belitung kaolin, 20% (by weight) of silica alumina, 20% (by weight) of silica sol. The slurry is fed to spray dryer with constant air temperature of 190oC, ratio of atomizing air flow to slurry feed rate between 0.75:1 to 1:1, hot air flow rate between 0.2-0.3 m3/min, and slurry feed rate between 15-20 mL/min. Catalyst particle size distribution produced is in the range of 0.3752-161.1770 µm. Angle of repose of the dry product isin the 41.45-49.00 range, which translates to a flowability between passable and poor. Statistical treatment of experimental data by ANOVA method indicates that hot air velocity and interaction between the atomizing air to slurry feed rate ratio and the hot air velocity significantly affect the average particle size. The interaction between the atomizing air to slurry feed ratio with hot air velocity significantly affect particle size distribution as well. Keywords: FCC catalyst; operation conditions; spray drying Abstrak Katalis FCC memiliki empat komponen yaitu zeolit, matriks, bahan pengisi, dan bahan pengikat. Katalis FCC berbentuk mikrosfer berukuran 10-120 µm. Produksi katalis FCC melibatkan operasi pengering sembur. Kondisi operasi pengering sembur mempengaruhi karakteristik katalis FCC mikrosfer. Campuran slurry (24% berat) memiliki komposisi 27% (berat) zeolit NaY, 33% (berat) kaolin Belitung, 20% (berat) silika alumina, 20% (berat) silika sol. Slurry diumpankan ke pengering sembur dengan temperatur udara konstan 190oC, nisbah antara laju udara atomisasiterhadap laju alir umpan 0,75:1-1:1, laju alir udara panas 0,2-0,3 m3/min, dan laju umpan masuk 15-20 mL/min. Percobaan menghasilkan distribusi ukuran partikel sebesar 0,3752 µm hingga 161,1770 µm. Nilai analisis sudut diam 41,4498 sampai 48,9666, menunjukkan kriteria sifat aliran antara passable dan poor. Pengolahan data percobaan dengan metode ANOVA menunjukkan kecepatan udara panas masuk dan interaksi antara nisbah laju udara atomisasi terhadap laju alir umpan dengan kecepatan udara panas masuk berpengaruh secara signifikan terhadap rata-rata ukuran partikel dan rentang distribusi ukuran katalis FCC.

Synthesis of NaY Zeolite Using Mixed Calcined Kaolins

Journal of Engineering and Technological Sciences Vol 47, No 6 (2015)
Publisher : ITB Journal Publisher, LPPM ITB

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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.

Thermal and Ash Characterization of Indonesian Bamboo and Its Potential for Solid Fuel and Waste Valorization

International Journal of Renewable Energy Development Vol 5, No 2 (2016): July 2016
Publisher : Center of Biomass & Renewable Energy, Dept. of Chemical Engineering, Diponegoro University

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Bamboo has been widely used in Indonesia for construction, handicrafts, furniture and other uses. However, the use of bamboo as a biomass for renewable energy source has not been extensively explored. This paper describes the thermal and ash characterization of three bamboo species found in Indonesia, i.e. Gigantochloa apus, Gigantochloa levis and Gigantochloa atroviolacea. Characterization of bamboo properties as a solid fuel includes proximate and ultimate analyses, calorific value measurement and thermogravimetric analysis. Ash characterization includes oxide composition analysis and phase analysis by X-Ray diffraction. The selected bamboo species have calorific value comparable with wood with low nitrogen and sulphur contents, indicating that they can be used as renewable energy sources. Bamboo ash contains high silicon so that bamboo ash has potential to be used further as building materials or engineering purposes. Ash composition analysis also indicates high alkali that can cause ash sintering and slag formation in combustion process. This implies that the combustion of bamboo requires the use of additives to reduce the risk of ash sintering and slag formation. Article History: Received May 15, 2016; Received in revised form July 2nd, 2016; Accepted July 14th, 2016; Available online How to Cite This Article: Purbasari, A., Samadhi, T.W. & Bindar, Y. (2016) Thermal and Ash Characterization of Indonesian Bamboo and its Potential for Solid Fuel and Waste Valorization. Int. Journal of Renewable Energy Development, 5(2), 95-100. 

The Effect of Alkaline Activator Types on Strength and Microstructural Properties of Geopolymer from Co-Combustion Residuals of Bamboo and Kaolin

Indonesian Journal of Chemistry Vol 18, No 3 (2018)
Publisher : Universitas Gadjah Mada

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Geopolymer as a Portland cement substitute had been synthesized from alkaline activation of co-combustion residuals of bamboo and kaolin. Types of used alkaline activators were NaOH solution, KOH solution, a mixture of NaOH solution-water glass, and a mixture of KOH solution-water glass. Geopolymer with NaOH solution as activator had a compressive strength which was higher compared to geopolymer with KOH solution as an activator. However, geopolymer with NaOH solution-water glass as activator had a compressive strength which was lower compared to geopolymer with KOH solution-water glass as activator either at room temperature curing or at a curing temperature of 60 °C. The use of water glass with NaOH or KOH solution as activator could increase the compressive strength of geopolymer and yielded geopolymer having more dense and more homogeneous microstructure seen from SEM images. XRD patterns revealed the presence of sodium aluminosilicate hydrate in geopolymer with NaOH solution and NaOH solution-water glass as activators, and potassium aluminosilicate hydrate in geopolymer with KOH solution and KOH solution-water glass as activators. Furthermore, FTIR spectra indicated asymmetrical vibration of Si(Al)-O at around 1008 cm-1 related to geopolymer product.