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STUDI KINETIKA PROSES ATMOSPHERIC PRESSURE ACID LEACHING BIJIH LATERIT LIMONIT MENGGUNAKAN LARUTAN ASAM NITRAT KONSENTRASI RENDAH Wanta, Kevin Cleary; Tanujaya, Felisha Hapsari; Susanti, Ratna Frida; Petrus, Himawan Tri Bayu Murti; Perdana, Indra; Astuti, Widi
Jurnal Rekayasa Proses Vol 12, No 2 (2018)
Publisher : Departemen Teknik Kimia Fakultas Teknik Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (671.213 KB) | DOI: 10.22146/jrekpros.35644

Abstract

A B S T R A C TKinetics study of atmospheric pressure acid leaching (APAL) process is indispensable for extractor design in an industrial scale. So far, the kinetic model used for this process is the shrinking core model. In this study, the shrinking core model was evaluated against experimental data for laterite leaching process using a solution of low concentration nitric acid (0.1 M). Variations in temperature and particle size were carried out at 303?358 K and <75?250 microns. Other operating conditions, such as pulp density, stirring speed, and time were kept at 20% w/v, 200 rpm, and 120 minutes, respectively. The model evaluation results showed that the shrinking core model was not suitable for this process because the process controlling stage is not just one stage only.Keywords: kinetics; laterite; leaching; shrinking core.A B S T R A KStudi terkait kinetika proses atmospheric pressure acid leaching (APAL) sangat diperlukan untuk proses perancangan ekstraktor dalam skala industri. Selama ini, model kinetika yang digunakan untuk proses tersebut adalah model shrinking core. Dalam studi ini, model shrinking core dievaluasi terhadap data percobaan proses leaching bijih laterit dengan menggunakan larutan asam nitrat konsentrasi rendah, 0,1 M. Variasi suhu dan ukuran partikel dilakukan pada 303?358 K dan <75?250 mikron. Kondisi operasi lainnya, seperti densitas pulp, kecepatan pengadukan, dan lama proses dijaga tetap pada 20%b/v, 200 rpm, dan 120 menit, secara berurutan. Hasil evaluasi model menunjukkan bahwa model shrinking core tidak cocok untuk proses ini karena tahapan pengendali proses tidak hanya satu tahapan saja.Kata kunci: kinetika; laterit; leaching; shrinking core
MODEL DISPERSI GAS DAN VAPOR CLOUD EXPLOSION PADA KEBOCORAN OUTLET PIGTAIL TUBES PRIMARY REFORMER Perwitasari, Perwitasari; Sumardi, Sumardi; Perdana, Indra
Jurnal Rekayasa Proses Vol 12, No 1 (2018)
Publisher : Departemen Teknik Kimia Fakultas Teknik Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (873.915 KB) | DOI: 10.22146/jrekpros.33802

Abstract

Outlet pigtail tubes, one of the components in primary reformer, have a function to carry the reformed gas from the catalyst tubes to the collection manifold. Moreover, it also has a function to provide the required flexibility within the system to avoid overstress at the end of connections of the pigtail to the manifold and to the bottom of the catalyst tube. It operates in an extreme condition with temperature range of 825-850 oC and pressure 36.2 kg/cm2 which is possible to initiate a failure. The consequences of outlet pigtail tubes failure are a dispersion of synthesis gas and vapor cloud explosion. This research aimed to make a model of those consequences with an assumption that the leakage hole was the same as the diameter of outlet pigtail tubes. The gas dispersion model used in this research was dense gas dispersion continuous release model. The results showed that the highest ratio of synthesis gas-air concentration was 0.1 at 17.4 m distance from leaking point. Whereas the lowest ratio of synthesis gas-air concentration was 0.002 at 163.4 m distance from leaking point. The highest ratio of the concentration of gas dispersion gave vapor cloud explosion energy of about 11.67 x 105 kJ with an overpressure of about 8.41 kPa. The overpressure caused a partial demolition of the building (for example control room), panels blow in, and fastening fails of equipment or machines around the area. A B S T R A KOutlet pigtail tubes adalah salah satu komponen pada primary reformer yang berfungsi untuk membawa gas hasil reforming dari tube katalis ke manifold. Selain itu outlet pigtail tubes juga berfungsi untuk memberikan fleksibilitas yang diperlukan di dalam sistem sehingga terhindar dari overstress di bagian akhir sambungan antara pigtail dengan manifold dan bagian bawah dari tube katalis. Outlet pigtail tubes beroperasi pada kondisi ekstrim yaitu suhu 825-850 oC dan tekanan 36,2 kg/cm2 yang mana memungkinkan untuk terjadinya kegagalan. Konsekuensi dari kegagalan outlet pigtail tubes adalah dispersi gas sintesis dan ledakan awan uap. Penelitian ini bertujuan untuk membuat model dari konsekuensi tersebut dengan asumsi bahwa lubang kebocoran sama dengan diameter outlet pigtail tubes. Model dispersi gas yang digunakan dalam penelitian ini adalah model dispersi dense gas untuk pengeluaran yang kontinu. Hasil menunjukkan bahwa rasio konsentrasi gas sintesis-udara tertinggi adalah 0,1 pada jarak 17,4 meter, sedangkan rasio konsentrasi terendah adalah 0,002 pada jarak 163,4 meter. Konsentrasi tertinggi dari gas terdispersi memberikan energi untuk ledakan awan uap sebesar 11,67 x 105 kJ dengan overpressure sebesar 8,41 kPa. Overpressure tersebut menyebabkan kerusakan pada sebagian dari bangunan (sebagai contoh ruang kontrol), terlemparnya papan, dan mempercepat kegagalan dari peralatan atau mesin di sekitar area.
KINETIKA PELARUTAN SILIKA AMORF DARI LUMPUR PANAS BUMI DIENG Riyanto, Nurdin; Sumardi, P; Perdana, Indra
Jurnal Rekayasa Proses Vol 6, No 1 (2012)
Publisher : Departemen Teknik Kimia Fakultas Teknik Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (375.699 KB) | DOI: 10.22146/jrekpros.2450

Abstract

Lumpur geotermal yang dihasilkan dari proses operasi Pembangkit Listrik Tenaga Panas Bumi Dieng mengandung silika amorf sebesar 50 %, yang sangat potensial untuk dijadikan sumber kebutuhan silika amorf untuk dunia industri. Penelitian ini bertujuan untuk mempelajari kinetika pelarutan silika amorf dari lumpur panas bumi dengan menvariasikan variabel ? variabel yang mempengaruhinya. Pada penelitian ini, alkali-solubilization yang merupakan proses pelarutan silika dalam larutan NaOH dalam labu berpengaduk dipelajari dengan memvariasikan variabel suhu (50 ? 90 °C), kecepatan pengadukan (150 ? 450 rpm), perbandingan molar Na/Si (2 ? 8), dan ukuran diameter padatan (0,0069 ? 0,01975 cm). Hasil penelitian menunjukkan bahwa laju pelarutan silika amorf dari limbah geotermal meningkat dengan naiknya suhu dan kecepatan pengadukan. Namun, ukuran padatan dan perbandingan molar pereaksi tidak menunjukkan pengaruh yang berarti terhadap proses pelarutan. Kata kunci: lumpur geotermal, silika amorf, alkali-solubilization, kinetika pelarutan Dieng?s geothermal power plant generates not only energy but also wastes as sludge that contains around 50% silica in an amorphous state. The waste has a great potential to be used as a source of micro-amorphous silica synthesis to fulfill industrial needs. This research aimed to study the dissolution kinetics of amorphous silica. In the present work, the alkali ? solubilization process by means of the dissolution of amorphous silica in an agitated flask was studied by varying process temperatures (50 ? 90C), stirring speed (150 ? 450 rpm), Na/Si molar ratio (2 ? 3), and silica particle size (0,0069 ? 0,01975 cm). Experimental results showed that the rate of geothermal silica dissolution increased with temperature and stirring speed. Meanwhile, Na/Si molar ratios and silica particle sizes showed no significant influence on the dissolution process. Calculation results indicated that the dissolution process involved a solid ? liquid reaction that occured at the solid surface. Keywords : geothermal sludge, amorphous silica, alkali-solubilization, dissolution kinetics
PENGARUH PENAMBAHAN SURFAKTAN SODIUM LIGNOSULFONAT (SLS) DALAM PROSES PENGENDAPAN NANO CALCIUM SILICATE (NCS) DARI GEOTHERMAL BRINE Ulya, M Ridho; Perdana, Indra; Mulyono, Panut
Jurnal Rekayasa Proses Vol 11, No 2 (2017)
Publisher : Departemen Teknik Kimia Fakultas Teknik Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (543.901 KB) | DOI: 10.22146/jrekpros.28245

Abstract

High concentration of dissolved silica in geothermal brine frequently causes operational problem in production of steam for electric generation.  Mitigation of silica scaling is necessary to reduce the risk of steam production failure. In the present work, silicic acid in Dieng geothermal brine was reduced by introduction of calcium hydroxide that lead to formation of insoluble nano calcium silicates (NCS).The purpose of this work was to control size of the precipitated NCS by introducing surfactant sodium lignosulfonate (SLS) as surfactant in the Ca(OH)2 added geothermal brine. The effect of temperature (30, 50 and 70°C), pH (7, 8 and 9), and surfactant concentration (0.05, 0.15 and 0.30% (w/v)) on the particle size of the resulting NCS was studied to obtain the optimum operating condition. The precipitation-sedimentation behavior of the resulting particles was measured in a vertical tube. Having measured the solid density and solution density and viscosity, average diameter of the precipitated particles was determined using stoke?s principle. The calculated particle size was the compared with measurement result using particle size analyzer (PSA). The soluble silica concentration in the solution was measured using spectroscopy method while composition of the resulting solid particles was measured using EDX and FTIR. Experimental results showed that the dissolve silica in Dieng geothermal brine can be reduced and controlled with the addition of Ca(OH)2 and surfactant SLS. The greater the concentration of surfactant SLS, the smaller the resulting particle size. It was found that the formation of NCS particles was accompanied with precipitation of silica and salts. The optimum condition of NCS formation was at temperature 30°C and pH 9 while the concentration of surfactant SLS added to the brine was 0.3 % (w/v).ABSTRAKKonsentrasi yang tinggi dari kelarutan silika dalam larutan geothermal menyebabkan masalah dalam pengoperasian produksi uap di PLTP Dieng. Mitigasi silika scaling diperlukan untuk mengurangi resiko kegagalan produksi uap. Dalam penelitian ini, asam silika dalam larutan geothermal direaksikan dengan kalsium hidroksida (Ca(OH)2) membentuk n ano calcium silicate (NCS). Tujuan penelitian ini adalah membentuk endapan NCS dari surfaktan SLS dan Ca(OH)2 ke dalam larutan geothermal. Mempelajari perubahan suhu (30, 50 dan 70°C), pH (7, 8 dan 9), dan konsentrasi surfaktan (0,05, 0,15 and 0,30% (w/v) serta mengetahui kondisi optimum. Pengujian yang dilakukan yaitu pengendapan partikel yang dilakukan di gelas ukur vertical, densitas padatan, densitas larutan, viskositas, dan diameter rata-rata partikel yang mengendap ditentukan dari persamaan diameter stokes. Kemudian membandingkan hasil perhitungan dari diameter stokes dengan particle size analyzer (PSA). Konsentrasi silika yang terlarut dapat diukur dengan metode spectroscopy dan komposisi padatan di uji dengan instrumen EDX dan FTIR. Hasil penelitian menunjukkan bahwa silika terlarut dalam larutan geothermal berkurang dan dapat dikontrol dengan penambahan Ca(OH)2 dan penambahan surfaktan SLS. Semakin besar konsentrasi surfaktan maka ukuran partikel akan semakin kecil. Pembentukan NCS dapat dihasilkan dan disertai juga dengan partikel silika dan garam. Kondisi optimum pembentukan NCS terjadi pada suhu 30 oC pH 9 dan konsentrasi surfaktan SLS 0,30 %w/v.
UJI VALIDITAS MODEL SHRINKING CORE TERHADAP PENGARUH KONSENTRASI ASAM SITRAT DALAM PROSES LEACHING NIKEL LATERIT Wanta, Kevin Cleary; Petrus, Himawan TBM; Perdana, Indra; Astuti, Widi
Jurnal Rekayasa Proses Vol 11, No 1 (2017)
Publisher : Departemen Teknik Kimia Fakultas Teknik Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (427.743 KB) | DOI: 10.22146/jrekpros.23321

Abstract

Atmospheric pressure acid leaching process is one of nickel laterite processing which has a big potential to be applied in industry. The leaching process is influenced by several factors and one of them is concentration of acid as leachant. The purpose of this present study is to learn the effect of concentration of citric acid  on the use of shrinking core kinetic model. The process was done by varying citric acid concentration at 0.1, 1, and 2 M. The other operation conditions, such as particle size, solid-liquid ratio, temperature, stirring speed, and leaching process were kept constant at 125-150 ?m, 0,2 sample mass/volume of acid solution, 85 oC, 200 rpm, and 120 minutes, respectively. The experimental results showed that the higher concentration of citric acid was used, the higher the percentage recovery of nickel was obtained. In addition, the validity test of shrinking core model indicated a positive impact to describe physical phenomenon of leaching process.ABSTRAKProses atmospheric pressure acid leaching merupakan salah satu proses pengolahan nikel laterit yang berpotensi untuk diaplikasikan dalam skala industri. Proses leaching ini dipengaruhi oleh beberapa faktor, diantaranya konsentrasi asam sebagai leachant. Studi ini dilakukan dengan tujuan untuk mempelajari pengaruh konsentrasi asam sitrat terhadap penggunaan model kinetika shrinking core dalam proses leaching nikel laterit. Proses leaching dilakukan dengan memvariasikan konsentrasi asam sitrat sebesar 0,1; 1,0, dan 2,0 M. Kondisi operasi lainnya, seperti ukuran partikel, rasio padat-cair, suhu, kecepatan pengadukan, dan lama proses dijaga konstan pada 125-150 ?m, 0,2 massa sampel/volume larutan asam, 85 oC, 200 rpm, dan 120 menit, secara berurutan. Hasil percobaan menunjukkan bahwa semakin tinggi konsentrasi asam sitrat yang digunakan, maka semakin tinggi pula nilai persentase recovery nikel yang diperoleh. Selain itu, uji validitas model shrinking core terhadap data percobaan menunjukkan dampak yang positif dalam mendeskripsikan fenomena fisis proses leaching. 
IMPLEMENTATION OF FUSION TALK APPLICATION IN NARRATIVE WRITING Perdana, Indra
IJER - INDONESIAN JOURNAL OF EDUCATIONAL REVIEW Vol 3 No 1 (2016): IJER (Indonesian Journal of Educational Review)
Publisher : Program Pascasarjana Universitas Negeri Jakarta

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (337.014 KB)

Abstract

This study aims to determine: (1) differences in narrative writing between the groups using Talk Fusion applications and groups not using the Talk Fusion applications, and (2) the effectiveness of the use of Talk Fusion applications in narrative writing for semester VI students of University of Palangka Raya. The study was an experimental study. The design of the study was Pre-test and Post-test Control Group Design. There are two variables in this study, namely the independent variable in the form of Talk Fusion applications and the dependent variable namely the narrative writing. The results of t-test calculation shows t scores that is greater than t table (th: 4.711&gt; tt: 1.980) at a significance level of 5% and db 70. This shows that there are significant differences in the narrative writing between groups by learning by using Talk Fusion applications and the group learning without the use of Talk Fusion applications. Scheffe test calculation results showed F count is higher than F table (Fh: 22.194&gt; Ft: 3.98) with 70 db and at a significance level of 5% of 36 students. This indicates that the value of the struggle of a character in biographies by using Talk Fusion applications are more effective than learning character that is not using Talk Fusion applications in the control group. Thus, it can be concluded that the use of Talk Fusion applications can improve the ability to write narrative.
Pemanfaatan LNG sebagai Bahan Bakar Kendaraan Umum di Yogyakarta: Tinjauan Aspek Keselamatan dalam Pengangkutan dan Penyimpanan Supriyadi, Didik; Mahrurrozi, Moh.; Perdana, Indra
Prosiding Seminar Nasional Teknik Kimia "Kejuangan" 2016: Prosiding SNTKK 2016
Publisher : Prosiding Seminar Nasional Teknik Kimia "Kejuangan"

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Abstract

Liquefied natural gas (LNG) has economic and technical benefits as an alternative fuel for public transportation and heavy-duty vehicle.  It is also safer, more reliable and more secure from domestic energy supply. However, LNG possesses different hazard compared to conventional automotive fuel.  This paper aims to discuss about risk analysis on LNG transportation and storage as part of an energy supply system for public transportation in Yogyakarta city.  This study was conducted for transportation routes between receiving terminal in Semarang port and storage facility in Yogyakarta.  Storage capacity was assumed to serve for 12-day-operation which is equivalent to three storages with a capacity of 53 m3 each. The results of risk analysis show that the causes of LNG release were failure of loading LNG to road tank and unloading to storage facility with frequency of 2,4 x10-3failures/year and 7,4 x 10-5 failures/year respectively. The study also found the most probable outcomes that give significant consequences were pool fire, fire ball, vapor cloud explosion and vapor cloud.  These results have led to the conclusion that LNG transportation and storage to support public transportation in Yogyakarta city is safe and reliable as long as a good standard operation procedure is consistently implemented
SINTESIS BIOADITIF GASOLINE MELALUI KETALISASI GLISEROL MENGGUNAKAN KATALISATOR PADAT Nuryoto, Nuryoto; Sulistyo, Hary; Sediawan, Wahyudi Budi; Perdana, Indra
Jurnal Bahan Alam Terbarukan Vol 5, No 2 (2016): December 2016 [Nationally Accredited]
Publisher : Semarang State University

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.15294/jbat.v5i2.7431

Abstract

Utilization of glycerol side product from biodiesel as waste management application is required for reduced   negative effect which possible emerged. Glycerol  have three bond of hydroxyde, so its  opportunity  to utilize  to be solketal as bio-additive of gasoline. Indion 225 Na ion exchanger resin is strong acid cation category and low  prices, so  its potency to use alternatively of solid catalyst to get efficient and economic process. The purpose of this research was focussed to search  of the best condition by optimalization indion 225 Na performance as catalyst in glycerol ketalization reaction, by integrated of variables that have effected to reaction for maximize glycerol coversion. To get maximize of reactants molecular interaction and for  optimalization indion 255 Na performance, observation  conducted  in the  range variables which widely enough that were  reactant ratio of 5:1-6:1 mole of acetone mole/mole of glycerol, diameter size  catalyst of  20-40 mesh, catalyst concentration of 3-5% mass of acetone, and reaction temperature of 35-65oC. Result of the research showed that  indion 225 Na catalyst have good performance, by glycerol conversion to reach of 51.89%. Glycerol conversion mentioned was obtained at reactant ratio of 6:1 mole of acetone/mole of gycerol, diameter size catalyst of  40 mesh, catalyst concentration of 4%  mass of acetone, and  reaction temperature of  65oC.
PENINGKATAN UNJUK KERJA KATALISATOR ZEOLIT ALAM BAYAH PADA REAKSI KETALISASI GLISEROL Nuryoto, Nuryoto; Sulistyo, Hary; Budi Sediawan, Wahyudi; Perdana, Indra
Reaktor Volume 17 No.1 Maret 2017
Publisher : Dept. of Chemical Engineering, Diponegoro University

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (489.371 KB) | DOI: 10.14710/reaktor.17.1.9-16

Abstract

Abstract IMPROVED PERFORMANCE OF BAYAH NATURAL ZEOLITE AS CATALYST ON   REACTION OF GLYCEROL KETALIZATION. The catalyst has an important role for the rates of chemical reactions accelerating in orde to achieve the target product of reaction. Reactants mass transfer to the active sites of the catalyst is oftenbe anobstacle to reaching of this purpose, so that the catalyst performance becomes less than the maximum. The objective of this research was to observe how much effected the diameter size catalyst, stirring speed, and catalyst concentration  in order to improved performance of Bayah natural zeolite catalyst on glycerol ketalization reaction based on glycerol conversion. The experiments were performed using a batch reactor, reaction temperature of 50oC, reactant ratio of 6:1 mol of acetone/mol of glycerol, reaction time of 90 minutes, diameter size catalyst from -18+25 until -60+70 mesh, catalyst concentration of 0-11% mass of glycerol, and stirring speed of 200-800 rpm. The results showed that the best conditions obtained at the diameter size catalyst of -40+45 mesh, catalyst concentration of 9% mass of glycerol, and stirring speed of 600 rpm by glycerol conversion reached of 60.92%. Keywords: glycerol; ketalization; performance; natural zeolite   Abstrak Katalisator mempunyai peranan penting dalam mempercepat laju reaksi kimia untuk mencapai target produk reaksi yang diinginkan. Perpindahan massa reaktan ke sisi aktif katalisator seringkali menjadi kendala dalam mencapaimaksud tersebut, sehingga unjuk kerja katalisator menjadi kurang maksimal. Penelitian ini bertujuan untuk melakukan observasi seberapa besar pengaruh ukuran diameter katalisator, kecepatan pengadukan, dan konsentrasi katalisator dalam rangka meningkatkan unjuk kinerja katalisator zeolit alam Bayah pada reaksi ketalisasi gliserol berbasis konversi gliserol yang dihasilkan. Percobaan dilakukan dengan menggunakan reaktor batch, suhu reaksi 50oC, perbandingan pereaksi 6:1 mol aseton/mol gliserol,waktu reaksi 90 menit, ukuran diameter katalisator -18+25 sampai -60+70 mesh, konsentrasi katalisator 0-11% massa gliserol, dan kecepatan  pengadukan 200-800 rpm. Hasil percobaan menunjukkan bahwa kondisi terbaik diperoleh pada ukuran diameter katalisator -40+45 mesh, konsentrasi katalisator 9% massa gliserol, dan  kecepatan pengadukan 600 rpm  dengan konversi gliserol mencapai 60,92%. Kata kunci: gliserol;  ketalisasi; unjuk kerja; zeolit alam
Nanosilika dari Prekursor Silika Geotermal: Pengaruh Konsentrasi Surfaktan dan Dekomposisi Termal Pasca Sintesis Rakhmasari, Kirana Dipta; Perdana, Indra; Prasetya, Agus; Pidhatika, Bidhari
Prosiding Seminar Nasional Teknik Kimia "Kejuangan" 2019: PROSIDING SNTKK 2019
Publisher : Prosiding Seminar Nasional Teknik Kimia "Kejuangan"

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Abstract

Nanosilica is often used in many sectors, such as pharmacy, ceramics, electronics, etc. Silica from geothermal power plant’s solid waste is oneof  natural silica precursor that contain a lot of amorphous silica (~97% SiO2). In this work sol-gel method was used to prepare nanoparticle. Surfactant was added  tothe sol phase to control the size of particles. The purpose of this work was to investigate the effects of surfactantconcentration ( 0,1% w/v, 0,2%w/v, and 0,4%w/v) on particle size of the resulting nanosilica and thermal decomposition of alkyl benzene sulfonate surfactant-remaining in the product-  following the synthesis process. Particle Size Analyzer (PSA) was used to analyze the size of particlesand thermal decomposition of the surfactant was measured using thermogravimetric analyser (TGA). The experimental resultsshowed that particle sizedecreases with increasing of surfactant concentration and the optimum concentration was 0,4% w/v. Decomposition temperature of the surfactant was about 330o C.