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All Journal Reaktor Journal of Engineering and Technological Sciences JURNAL SELULOSA ASEAN Journal of Chemical Engineering Jurnal Teknologi Bahan dan Barang Teknik Jurnal Teknik Kimia Indonesia Bulletin of Chemical Reaction Engineering & Catalysis
S. Subagjo
Chemical Engineering Department, Institut Teknologi Bandung
Biochemistry, Genetics & Molecular Biology Chemical Engineering, Chemistry & Bioengineering Chemistry Computer Science & IT Control & Systems Engineering Education Electrical & Electronics Engineering Energy Engineering Materials Science & Nanotechnology

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Dynamic Behavior of Reverse Flow Reactor for Lean Methane Combustion Budhi, Yogi W.; Effendy, M.; Bindar, Yazid; Subagjo, S.
Journal of Engineering and Technological Sciences Vol 46, No 3 (2014)
Publisher : ITB Journal Publisher, LPPM ITB

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (1273.272 KB) | DOI: 10.5614/j.eng.technol.sci.2014.46.3.5

Abstract

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.
Determination of Kinetic Parameters for Methane Oxidation over Pt/γ-Al2O3 in a Fixed-Bed Reactor Wonoputri, Vita; Effendy, Mohammad; Budhi, Yogi Wibisono; Bindar, Yazid; Subagjo, S.
Journal of Engineering and Technological Sciences Vol 45, No 2 (2013)
Publisher : ITB Journal Publisher, LPPM ITB

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (518.085 KB) | DOI: 10.5614/j.eng.technol.sci.2013.45.2.7

Abstract

This paper describes akinetic study for the determination of the kinetic parameters of lean methane emission oxidation over Pt/γ-Al2O3 in a dedicated laboratory scale fixed bed reactor. A model ofthemechanistic reaction kinetic parameters has been developed. The reaction rate model was determined using therate-limiting step method, which was integrated and optimized to find the most suitable model and parameters. Based on this study, the Langmuir-Hinshelwood reaction rate model with the best correlationis the one where the rate-limiting step is thesurface reaction between methane and one adsorbed oxygen atom. The pre-exponential factor and activation energy were 9.19 x 105 and 92.04 kJ/mol, while the methane and oxygen adsorption entropy and enthalpy were –17.46 J/mol.K, –2739.36 J/mol,–16.34 J/mol.K, and –6157.09 J/mol, respectively.
Homogeneity of Continuum Model of an Unsteady State Fixed Bed Reactor for Lean CH4 Oxidation Subagjo, S.; Budhi, Yogi Wibisono; Effendy, M.; Bindar, Yazid
Journal of Engineering and Technological Sciences Vol 46, No 2 (2014)
Publisher : ITB Journal Publisher, LPPM ITB

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (479.426 KB) | DOI: 10.5614/j.eng.technol.sci.2014.46.2.6

Abstract

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.
Synthesis of -Al2O3 Catalyst Support from Kaolin of Indonesian Origin Samadhi, Tjokorde Walmiki; Subagjo, Subagjo; Lismana, Kevin R.; Fuadi, Khasin
Journal of Engineering and Technological Sciences Vol 43, No 2 (2011)
Publisher : ITB Journal Publisher, LPPM ITB

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (140.925 KB) | DOI: 10.5614/itbj.eng.sci.2011.43.2.3

Abstract

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.
Synthesis and Activity Test of Cu/ZnO/Al2O3 for the Methanol Steam Reforming as a Fuel Cell’s Hydrogen Supplier Makertihartha, IGBN; Subagjo, Subagjo; Gunawan, Melia Laniwati
Journal of Engineering and Technological Sciences Vol 41, No 1 (2009)
Publisher : ITB Journal Publisher, LPPM ITB

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (532.438 KB) | DOI: 10.5614/itbj.eng.sci.2009.41.1.3

Abstract

The  synthesis  of  hydrogen  from  hydrocarbons  through  the  steam reforming  of  methanol  on  Cu/ZnO/Al2O3  catalyst  has  been  investigated.  This process is assigned to be one of the promising alternatives for  fuel cell hydrogen process source. Hydrogen synthesis from methanol can be carried out by means of  methanol  steam  reforming  which  is  a  gas  phase  catalytic  reaction  between methanol and water. In this research, the  Cu/ZnO/Al2O3  catalyst  prepared by the dry  impregnation  was  used.  The  specific  surface  area  of  catalyst  was  194.69 m2/gram.The  methanol  steam  reforming  (SRM)  reaction  was  carried  out  by means of the injection of gas mixture containing methanol and water with 1:1.2 mol ratio and 20-90 mL/minute feed  flow rate to a fixed bed reactor loaded by 1 g of catalyst. The reaction temperature was 200-300 °C, and the reactor pressure was 1 atm. Preceding  the reaction, catalyst was reduced in the H2/N2  mixture at 160  °C.  This  study  shows  that  at  300  °C  reaction  temperature,  methanol conversion  reached  100%  at  28  mL/minute  gas  flow  rate.  This  conversion decreased  significantly  with  the  increase  of  gas  flow  rate.  Meanwhile,  the catalyst prepared for SRM  was stable in 36 hours of operation at 260  °C. The catalyst exhibited a good stability although the reaction condition was shifted to a higher gas flow rate.
The Influence of PEG400 and Acetone on Polysulfone Membrane Morphology and Fouling Behaviour Aryanti, P.T.P.; Joscarita, Shelli R.; Wardani, Anita K.; Subagjo, S.; Ariono, Danu; Wenten, I Gede
Journal of Engineering and Technological Sciences Vol 48, No 2 (2016)
Publisher : ITB Journal Publisher, LPPM ITB

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (292.652 KB) | DOI: 10.5614/j.eng.technol.sci.2016.48.2.1

Abstract

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.
Pengembangan katalis Kalsium Oksida untuk sintesis biodiesel Widdy Andya Fanny; S Subagjo; Tirto Prakoso
Jurnal Teknik Kimia Indonesia Vol 11, No 2 (2012)
Publisher : ASOSIASI PENDIDIKAN TINGGI TEKNIK KIMIA INDONESIA (APTEKIM)

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.5614/jtki.2012.11.2.1

Abstract

The Improvement of Calcium Oxide Catalyst for Biodiesel Synthesis The development of industrial’s sector resulted in increasing demand for fuel. Fuel used is obtained from fossil fuel which is limited, and it produces several harmful gases to environment. To overcome these obstacles, the research on alternative energy resources has begun. Biodiesel has become more attractive because of its environmental benefits and it is made from renewable resources. Biodiesel is produced from vegetable oil by transesterification reaction. The aim of this research is development of CaO become super base CaO as heterogeneous for biodiesel synthesis by transesterification. The activities of both catalysts were tested by transesterification reaction in batch reactor at 60–65 oC for 4 hours. Both of those catalysts were characterized; include crystallinity by XRD, strength of base and surface area by BET method. Those solids have the basic strength about 10–11, crystalline structures, and the surface area of super base CaO about 7.7 m2/g and CaO about 9.6 m2/g. The content of methyl ester in biodiesel produced reaches 98.8%. According to SNI (minimal 96.5 %-wt) and ASTM, biodiesel of this reaction can be used as renewable energy source. Keywords: CaO, super base CaO, transesterification, biodiesel Abstrak Berkembangnya industri di dunia mengakibatkan meningkatnya kebutuhan akan bahan bakar. Selama ini bahan bakar yang digunakan diperoleh dari bahan bakar fosil yang jumlahnya terbatas, terlebih lagi hasil pembakaran bahan bakar fosil cenderung tidak ramah lingkungan. Untuk mengatasi berbagai kendala yang ditimbulkan dari penggunaan bahan bakar fosil, penelitian terhadap sumber energi alternatif mulai dilakukan. Biodiesel menarik perhatian dunia karena hasil pembakarannya lebih ramah lingkungan dan berasal dari sumber yang terbarukan. Biodiesel dihasilkan dari minyak nabati melalui reaksi transesterifikasi.Penelitian ini mengembangkan katalis CaO menjadi katalis CaO super basa untuk reaksi transesterifikasi pembentukan biodiesel. Aktivitas katalis CaO dan katalis CaO super basa tersebut diuji melalui reaksi transesterifikasi di dalam reaktor partaian pada suhu 60–65 oC selama 4 jam. Karakterisasi padatan meliputi uji kristalinitas dengan metode XRD, uji kekuatan basa, dan uji luas permukaan dengan metode BET. Hasil penelitian menunjukkan bahwa padatan memiliki kekuatan basa berkisar 10–11, bersifat kristalin, dan memiliki luas permukaan sebesar 7,7 m2/g untuk CaO super basa dan 9,6 m2/g untuk CaO. Kadar metil ester biodiesel yang dihasilkan mencapai 98,8%. Kadar metil ester menurut SNI (minimal 96,5 %-b) dan ASTM, biodiesel dari reaksi ini dapat digunakan sebagai sumber energi terbarukan. Kata Kunci: CaO, CaO super basa, transesterifikasi, biodiesel
Sintesis y-alumina sebagai penyangga katalis T. Walmiki Samadhi; S. Subagjo; Temy Nurfahmiawati
Jurnal Teknik Kimia Indonesia Vol 6, No 1 (2007)
Publisher : ASOSIASI PENDIDIKAN TINGGI TEKNIK KIMIA INDONESIA (APTEKIM)

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.5614/jtki.2007.6.1.5

Abstract

Synthesis of y-alumina as catalist supportOf the numerous catalyst support materials utilized in the petroleum refining industry, y-alumina is one ofthe most commonly used materials, especially in the hydrotreating processes. Due to the large­ scale application of y-alumina, a competence in the synthesis of this material is essential in an effort to reduce the dependency of catalyst development in Indonesia on imported materials. The objectives of this research is to identify key variables in the synthesis of y-alumina according to a sol-gel procedure patented by Rana et al., which utilizes aluminum nitrate as the precursor for the formation of boehmite gel, which in turn is calcined to obtain they-alumina phase. The synthesis is undertaken in 23 full factorial experiment design involving type of base (gelling agent), concentration of base, and aging time as experimental variables. Types of base in this research are ammonium carbonate and urea. Concentrations of base and aging time were varied at 50% and 200% relative to the values set in the patented procedure. Analysis of variance (ANOVA) of the specific surface area results at a confidence level of 95% indicates the significance of type and concentration of base, and the interaction between the two variables. The highest specific surface area obtained is 195.16 m2/g, using ammonium carbonate at a concentration of 5.05 mole/mole aluminum nitrates and aging time of 20 hours. This specific surface area is higher than that stated in Rana's procedure, which is namely 175 m2/g.Keywords: y-alumina, catalyst support, specific surface area, ANOVAAbstrakDari berbagai material penyangga katalis yang digunakan dalam industri pengilangan minyak bumi, y-alumina merupakan salah satu material yang paling umum digunakan, terutama dalam proses-proses hydrotreating. Sehubungan dengan luasnya penggunaan y-alumina, sintesis material ini merupakan kompetensi kunci yang sangat penting dalam upaya mengurangi ketergantungan pengembangan katalis di Indonesia terhadap bahan-bahan impor. Tujuan penelitian ini adalah mengindentifikasi variabel-variabel kunci dalam sintesis y-alumina menurut metode sol-gel yang dipatenkan oleh Rana dkk., yang menggunakan aluminum nitrat sebagai bahan awal pembentukan gel boehmite, yang selanjutnya dikalsinasi untuk memperoleh fasa y-alumina. Sintesis dilaksanakan pada rancangan percobaan statistik 23 full factorial yang melibatkan jenis basa (sebagai gelling agent), konsentrasi basa, dan waktu aging sebagai variabel-variabel percobaan. Jenis-jenis basa yang digunakan dalam penelitian ini adalah amonium karbonal dan urea. Konsentrasi  basa dan waktu aging divariasikan pada 50% dan 200% dari nilai yang digunakan dalam prosedur paten Rana dkk. Analisis varians (ANOVA) terhadap hasil pengukuran luas permukaan spesifik pada tingkat keyakinan 95% menunjukkan signifikansi jenis dan konsentrasi basa, serta interaksi antara kedua variabel tersebut. Luas permukaan spesifik tertinggi yang diperoleh adalah 195,16 m2/g, dengan menggunakan amonium karbonat pada konsentrasi 5,05 mol/mol aluminum  nitrat,  dan waktu aging 20 jam. Luas permukaan ini lebih tinggi daripada nilai yang dicantumkan dalam prosedur Rana, yakni sebesar 175 m2/g.Kata kunci: y-alumina, penyangga katalis, luas permukaan spesifik, ANOV
Pengembangan katalis Ni/Al2o3 untuk steam reforming tar hasil gasifikasi Deviana Pramitasari; S Subagjo
Jurnal Teknik Kimia Indonesia Vol 10, No 2 (2011)
Publisher : ASOSIASI PENDIDIKAN TINGGI TEKNIK KIMIA INDONESIA (APTEKIM)

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.5614/jtki.2011.10.2.1

Abstract

The development of catalysts Ni/Al2O3 for steam reforming gasification tar This research studied the secondary tar removal in gasification technology through catalytic toluene steam reforming reactions. The objective of this study was to obtain a nickel catalyst that has good performance for steam reforming of tar (toluene) by selecting the -Al2O3 or -Al2O3 supports, and adding promoter to inhibit deactivation due to coke formation. The performance of the catalyst is determined from the activity test in a fixed bed reactor at a temperature of 700 oC, atmospheric pressure, Time on Stream (TOS) 10 hours and stability test indicated by XRD and TGA. The catalyst showed the best performance was the Ni/-Al2O3 catalyst with the average of toluene conversion of 96%. The addition of 2% and 5% by weight of CaO decreased the catalytic activity. Although it proved to inhibit the formation of coke, it did not reduce the rate of deactivation of catalyst. The XRD analysis showed that the Ni/-Al2O3 after 10 hours in operation did not undergo any phase changes, thus the catalyst was still stable. Keywords: tar cracking, steam reforming, nickel catalyst, toluene conversion, stability. AbstrakPenelitian ini merupakan suatu bagian dalam pengembangan teknologi penghilangan tar gasifikasi secara sekunder dengan cara perengkahan katalitik menggunakan reaksi steam reforming toluen. Tujuan penelitian ini adalah mendapatkan katalis berbasis nikel yang memiliki kinerja yang baik untuk steam reforming tar (toluen) dengan memilih penyangga -Al2O3 atau -Al2O3, dan menambah promotor CaO untuk menghambat deaktivasi akibat pembentukan arang. Kinerja katalis ditentukan dari uji aktivitas di dalam reaktor fixed bed pada temperatur 700 oC, tekanan atmosferik, selama 10 jam dan uji stabilitas yang diindikasikan menggunakan XRD dan TGA. Hasil pengujian aktivitas memperlihatkan bahwa katalis Ni/-Al2O3 menghasilkan aktivitas yang paling baik dengan rata - rata konversi toluen 96%. Penambahan promotor CaO 2% dan 5% berat menurunkan aktivitas katalis Ni/-Al2O3 dan menghambat pembentukan arang, tetapi tidak mengurangi laju deaktivasi katalis. Hasil XRD katalis Ni/-Al2O3 setelah reaksi 10 jam menunjukkan tidak adanya perubahan fasa dari -Al2O3 ke -Al2O3, yang berarti katalis masih tetap stabil.Kata Kunci: perengkahan tar, katalis nikel, konversi toluen, stabilitas.
Pembuatan dan uji aktivitas katalis htsc berbasis besi oksida Fitri Rumiani; S Subagjo
Jurnal Teknik Kimia Indonesia Vol 6, No 3 (2007)
Publisher : ASOSIASI PENDIDIKAN TINGGI TEKNIK KIMIA INDONESIA (APTEKIM)

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.5614/jtki.2007.6.3.6

Abstract

High temperature shift conversion is a water gas shift reaction using water to produce carbon dioxide and hydrogen in high temperature (370-400oC). The aim of this research is examining the preparation procedure of HTSC catalyst. The catalyst made by Co-precipitation method of Fe and Cr nitrate solution with Na2CO3 as precipitating agent. The specific surface area of catalyst is determined by BET method. The crystal structure was analyzed by XRD method. The catalyst activity was evaluated in the fixed bed reactor on laboratory scale with 370oC and 1 atm. The result shows that the preparation procedure of HTSC ITB catalyst is reproducible. Based on the preparation procedure, calcinations temperature has a great influence to the catalyst surface area. The calcinations temperature at 300oC gave the highest catalyst surface area (198 m2/g), and it is comparable with the surface area claimed by Jennings (200 m2/g). The catalyst has also the highest activity by means of CO conversion resulted by the catalyst activity test (86%) which is larger than commercial catalyst conversion (81%)Keywords : Activity, Catalyst based on Fe/Cr, HTSC, Precipitation Abstrak High temperature shift conversion (HTSC) merupakan reaksi pergeseran CO menggunakan air menjadi CO2 dun H2 yang diselenggarakan pada temperatur tinggi (370-400oC). Penelitian ini bertujuan untuk mendapatkan resep dan prosedur pembuatan katalis HTSC. Katalis dibuat dengan metode kopresipitasi larutan garam nitrat dart Fe dan Cr dengan Na2CO3 sebagai senyawa pengendap. Untuk mengetahui keberhasilan penelitian ini, dilakukan penentuan luas permukaan, struktur kristal, dan aktivitas katalis yang kemudian dibandingkan dengan katalis komersial. Luas permukaan spesiftk diukur menggunakan metode BET, sedangkan struktur kristal dianalisis menggunakan XRD. Uji aktivitas katalis dilakukan dalam reaktor fixed bed skala laboratorium pada 370oC dan 1 atm. Hasil penelt.tian menunjukkan bahwa pelaksanaan prosedur pembuatan katalis HTSC ITB sudah dapat diulangi dengan hasil yang sama (reproducible). Berdasarkan prosedur tersebut, temperatur kalsinasi sangat berpengaruh terhadap lnas permukaan katalis. Dalam rentang temperatur yang dipelajari (300-400oC), kalsinasi pada temperatur 300oC menghasilkan katalis dengan luas permukaan paling tinggi yaitu 192-198 m2/g. Makin tinggi luas permukaan katalis yang dihasilkan, makin tinggi aktivitas katalis tersebut. Katalis dengan luas permukaan 192-198 m2/g menghasilkan aktivitas paling tinggi, konversi CO yang dihasilkan adalah 86 %, sedikit lebih besar dari konversi katalis komersial (81 %).Kata Kunci : Aktivitas, HTSC, Katalis berbasis Fe/Cr, Prespitasi
Co-Authors Achmad Syamsul Arief Adnanta Rio Agus Subekti Ahlul Hafizan Resha Anita K. Wardani Anita K. Wardani, Anita K. Danu Ariono Danu Ariono David Bahrin Deviana Pramitasari Endang Sri Rahayu Endar Puspawiningtiyas Fitri Rumiani Galang Putra Persada Hendra Suherman Herri Susanto I Gede Wenten I.G.B Ngurah Makertihartha IGBN Makertihartha IGBN Makertihartha IGBN Makertihartha Kadja, Grandprix Thomryes Marth Kevin R. Lismana Kevin R. Lismana Khasin Fuadi Khasin Fuadi M. Effendy M. Effendy M. Effendy M. Effendy M. Effendy Maria Ulfah Meiti Pratiwi Melia L. Gunawan Melia Laniwati Melia Laniwati Gunawan Melia Laniwati Gunawan Melia Laniwati Gunawan Melia Laniwati Gunawan Mohammad Effendy Mohammad Effendy P.T.P. Aryanti P.T.P. Aryanti, P.T.P. Praharso Paharso Praharso Praharso Pratama Istiadi Rino R. Mukti Shelli R. Joscarita Shelli R. Joscarita, Shelli R. Syamsudin Syamsudin Syamsudin Syamsudin T. Walmiki Samadhi Tatang Hernas Soerawidjaja Temy Nurfahmiawati Tirto Prakoso Tjokorde Walmiki Samadhi Tjokorde Walmiki Samadhi Tjokorde Walmiki Samadhi Tobias Richards Ulfah, Maria Vita Wonoputri Vita Wonoputri Widdy Andya Fanny Winny Wulandari, Winny Yazid Bindar Yazid Bindar Yazid Bindar Yazid Bindar Yogi W. Budhi Yogi W. Budhi Yogi Wibisono Budhi Zaky Al Fatony