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Addition of egbe and ethanol to enhance mes performance as chemical flooding material Dewi Tristantini; Humala Paulus Hakim; Muhammad Fadly Zuliardy
Jurnal Teknik Kimia Indonesia Vol 10, No 3 (2011)
Publisher : ASOSIASI PENDIDIKAN TINGGI TEKNIK KIMIA INDONESIA (APTEKIM)

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.5614/jtki.2011.10.3.2

Methyl ester sulfonate (MES) performance as chemical flooding material for EOR was investigated by adding emulsifier ethyl glycol mono butyl ether (EGBE) and ethanol. MES had interfacial tension (IFT) value as low as 10-3 dyne/cm, but its disadvantage was low solubility in brine water. Repairing this nature, MES was modified by adding nonyl phenol ethoxylate (Tergitol, as secondary surfactant), EGBE and ethanol. The mixed surfactant was tested for IFT value, solubility, and thermal influence to IFT value in various concentrations. The result indicated a significant effect of emulsifier concentration to IFT value. The longer carbon chains, the easier micelle interaction was formed. The positive effects to solubility were caused by the polarity of long chain EGBE and the increase of micro emulsion stability by ethanol. The best formulas were 1% concentration surfactant in brine water consist of MES 40%, Tergitol 20%, ethanol 40% and 0.3% of MES 40%, Tergitol 20%, EGBE 40%. These formulas also had better solubility than MES alone, since they only form one phase. Heat treatment at 62.5 oC for 1 day caused lower IFT because of increasing interaction between emulsifier and micelle. Further heating resulted in a higher IFT as the emulsifier structure collapsed, which made interactions difficult to achieve. Keywords: EOR, interfacial tension, methyl ester sulfonate, non-ionic, surfactantAbstrakKinerja metil ester sulfonat (MES) sebagai bahan chemical flooding untuk EOR telah dilakukan dengan menambahkan pengemulsi etil glikol mono butil eter (EGBE) dan etanol. MES memiliki nilai tegangan permukaan (IFT) sebesar 10-3 dyne/cm, tetapi memiliki kelarutan yang rendah dalam air formasi. Untuk memperbaiki sifat ini, MES ditambahkan dengannonyl phenol ethoxylate (Tergitol) sebagai surfaktan kedua, EGBE dan etanol. Hasil formulasi surfaktan diuji nilai IFT, kelarutan dan pengaruh termal terhadap nilai IFT dalam berbagai tingkat konsentrasi. Hasil pengujian mengindikasikan adanya pengaruh konsentrasi pengemulsi yang besar terhadap nilai IFT. Rantai karbon yang lebih panjang berakibat semakin mudah interaksi micelle terjadi. Kelarutan yang semakin tinggi disebabkan polaritas dari rantai panjang EGBE dan meningkatnya stabilitas mikroemulsi oleh alkohol. Hasil formulasi terbaik didapatkan pada konsentrasi surfaktan 1% dengan MES 40%, Tergitol 20%, Alkohol 40% dan konsentrasi surfaktan 0,3% dengan MES 40%, Tergitol 20%, EGBE 40%. Formula ini memiliki kelarutan yang lebih baik daripada MES karena hanya membentuk 1 fase. Pengaruh pemanasan 62,5 oC selama 1 hari menyebabkan IFT semakin rendah karena meningkatnya interaksi antara pengemulsi dan micelle. Pemanasan yang berlebihan menyebabkan IFT naik karena rusaknya struktur pengemulsi sehingga interaksi sulit terjadi.Kata kunci: EOR, metil ester sulfonat, non-ionik, surfaktan, tegangan permukaan

Pengujian Aktivitas Antioksidan Menggunakan Metode DPPH pada Daun Tanjung (Mimusops elengi L) Dewi Tristantini; Alifah Ismawati; Bhayangkara Tegar Pradana; Jason Gabriel Jonathan
Prosiding Seminar Nasional Teknik Kimia "Kejuangan" 2016: Prosiding SNTKK 2016
Publisher : Seminar Nasional Teknik Kimia Kejuangan

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Mimusops elengi L is one of the plantfrom India, Sri Lanka and Burma that have potential as antioxidant which can be used to treat various disease. The main content of the ethanol extract of the leaves Mimusops elengi L which have antioxidant activity are quercetin, hentriacontane, and β-carotenewhich is a source of natural antioxidants.Extraction using reflux method by varying the extraction time 15 minutes, 30 minutes, 45 minutes, 60 minutes and 75 minutes. The extract of leaves of M. elengi were prepared in methanol. The measurement of antioxidant activity carried out using DPPH method. The result showed that the extract ethanol at 45 minutes variaty of time extraction have the highest antioxidant activity, with IC50 value were 10,6.

Pengaruh Penambahan Kacang Merah, Ampas Kedelai, dan Textured Vegetable Protein pada Kandungan Nutrisi dan Tekstur Daging Sapi Sintetik Dewi Tristantini; Angela Susanti
Prosiding Seminar Nasional Teknik Kimia "Kejuangan" 2016: Prosiding SNTKK 2016
Publisher : Seminar Nasional Teknik Kimia Kejuangan

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As beef consumption can increase risk of cancer and cardiovascular disease, an alternative food in the form of synthetic beef which contains important nutrients with less health risk can be made. In this research, protein content will be derived from gluten, kidney bean, soy pulp, and textured vegetable protein which are varied in concentration. Our results indicated that increase of kidney bean flour and textured vegetable protein will increase ash, protein, and fat content while increase of soy pulp will increase water and carbohydrate content, decrease the amount of calories, and reduce synthetic beef’s hardness. The best synthetic beef has been made with a combination of 60% gluten, 10% kidney bean flour, 20% soy pulp, and 10% textured vegetable protein. According to proximate and calorimetry analysis, the best synthetic beef contained 60.3% water, 0.6% ash, 19.3% protein, 4.5% fat, 15.6% carbohydrate, and 178 kal/100 g. According to texture profile analysis, the best synthetic beef had 0.570 cohesiveness, 5845.4 gf hardness, and 88.0 springiness. Synthetic beef has similar cohesiveness and elasticity but higher hardness than beef. Based on this research, synthetic beef with sufficient amount of nutrient and less health risk has been produced.

Outcome of Soybean Dregs and Cassava Addition towards Synthetic Chicken Meat Texture and Nutrition Dewi Tristantini; Tiara Febriani; Monica Winata
Prosiding Seminar Nasional Teknik Kimia "Kejuangan" 2016: Prosiding SNTKK 2016
Publisher : Seminar Nasional Teknik Kimia Kejuangan

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Meat is one of the main sources of protein that society enjoys consuming, particularly chicken. However, meat may be unhealthy and cause excessive cholesterol, diabetes, and weight gain, also pathogenic such as avian influenza. Meat alternative that is healthier is synthetic meat. Synthetic meat is created from organic ingredients with protein content that resembles meat. Protein in synthetic meat is obtained from ingredients such as gluten, soybean dregs, and cassava. Aside from protein, other nutrition such as fiber, carbohydrate, fats, and minerals are also incorporated in synthetic meat. In manufacturing synthetic meat, the concentration of soybean dregs and cassava are varied in order to observe the effect from both ingredients towards nutrition and texture. Synthetic meat will be analyzed proximately, calorimetrically, its texture by texture profile analysis (TPA) and scanning electron microscopy (SEM), shelf life, and amino acids. From this research, a formulation for synthetic chicken meat is obtained based on its nutrition and texture. The best composition for synthetic chicken meat consists of 60% gluten, 5% cassava, and 20% soybean dregs.

Lump Kinetic Analysis of Syngas Composition Effect on Fischer-Tropsch Synthesis over Cobalt and Cobalt-Rhenium Alumina Supported Catalyst Dewi Tristantini; Ricky Kristanda Suwignjo
Bulletin of Chemical Reaction Engineering & Catalysis 2016: BCREC Volume 11 Issue 1 Year 2016 (April 2016)
Publisher : Department of Chemical Engineering - Diponegoro University

This study investigated lump kinetic analysis of Fischer-Tropsch synthesis over Cobalt and Cobalt-Rhenium Alumina supported catalyst (Co/γ-Al2O3 and Co-Re/γ-Al2O3) at 20 bars and 483 K using feed gas with molar H2/CO ratios of 1.0 to 2.1. Syngas with H2/CO molar ratio of 1.0 represents syngas characteristic derived from biomass, while the 2.1 molar ratio syngas derived from coal. Rhenium was used as the promoter for the cobalt catalyst. Isothermal Langmuir adsorption mechanism was used to build kinetic model. Existing kinetic model of Fischer-Tropsch synthesis over cobalt alumina supported catalysts only valid for operating pressure less than 10 bar. CO insertion mechanism with hydrogenation step of catalyst-adsorbed CO by catalyst-adsorbed H component as the rate-limiting step is valid for operating condition in this research. Higher H2/CO ratio makes faster hydrogenation step and less-product dominated in the associative CO adsorption step and dissociative H2 adsorption equilibrium step. Kinetic constant for hydrogenation step increases 73-421% in syngas with 2.1 H2/CO molar ratio compared to condition with 1.0 H2/CO molar ratio. Faster hydrogenation step (with higher kinetic constant) results in higher reactant conversion. Equilibrium constant for associative CO adsorption and dissociative H2 adsorption step decreases 53-94% and 13-82%, respectively, in syngas with higher H2/CO molar ratio. Less product dominated reactant adsorption step (lower equilibrium constant for CO and H2 adsorption step) gives higher CH4 product selectivity, which occurred on 2.1 molar ratio of syngas. Rhenium (Re) metal on cobalt catalyst with composition 0.05%Re-12%Co/γ-Al2O3 only gives effect as structural promoter, which only increases reactant conversion with the same product selectivity.

Suhu dan Rasio Kukus Optimum pada Proses Gasifikasi Kukus Berkatalis K2CO3 terhadap Arang Batu bara Lignit Hasil Pirolisis dengan Laju Pemanasan Terkontrol Dewi Tristantini; Ricky Kristanda Suwignjo
Jurnal Rekayasa Proses Vol 8, No 2 (2014)
Publisher : Departemen Teknik Kimia Fakultas Teknik Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22146/jrekpros.11372

In order to fulfill the raw material needs of Fischer Tropsch process for producing synthethic fuel (synfuel), high yield of synthesis gas (syngas) with H2/CO ratio ≈ 2.0 should be obtained from lignite coal gasification. Steam gasification can enhance H2 composition in syngas. Lower activation energy of gasification reaction can be obtained using K2CO3 catalyst during the process. Pyrolysis step with controlled heating rate will affect pore surface area of char which will influence the composition and yield of syngas. In this study, lignite char from pyrolysis with controlled heating rate with 172.5 m2/g surface area and K2CO3 catalyst was fed in fixed bed steam gasification reactor. Steam to char mass ratio (2.0; 3.0; 4.0) and gasification temperature (675; 750; 825C) was varied. Optimum condition for syngas production obtained in this study was steam gasification at 675C with steam/char mass ratio 2.0. This condition will produce syngas with H2/CO ratio 2.07 and gas yield 1.128 mole/mole C (45% carbon conversion). Keywords: lignite, controlled pyrolysis, catalytic steam gasification, fixed bed reactor Untuk memenuhi persyaratan bahan baku pembuatan bahan bakar cair sintetis (synfuel) melalui proses Fischer Tropsch, diperlukan proses gasifikasi batu bara lignit yang menghasilkan gas sintesis dengan rasio H2/CO ≈ 2,0 dan yield gas yang tinggi. Metode gasifikasi kukus dapat meningkatkan komposisi H2 dalam gas sintesis. Energi aktivasi reaksi gasifikasi dapat diturunkan dengan menggunakan katalis K2CO3. Laju pemanasan terkontrol pada tahap pirolisis menentukan ukuran pori arang yang berpengaruh pada komposisi dan yield gas sintesis. Penelitian ini dilakukan dengan mengumpankan arang batu bara lignit hasil pirolisis dengan laju pemanasan terkontrol yang memiliki luas permukaan pori 172,5 m2/g bersama dengan katalis K2CO3 ke dalam reaktor unggun tetap. Rasio massa kukus/arang yang ditambahkan bervariasi 2,0; 3,0; 4,0 dan suhu gasifikasi 675, 750, 825C. Hasil penelitian ini menunjukkan bahwa kondisi reaksi gasifikasi yang sesuai untuk produksi gas sintesis bahan baku proses Fischer Tropsch adalah reaksi gasifikasi berkatalis K2CO3 pada suhu 675C dan rasio massa kukus/arang 2,0. Kondisi ini menghasilkan gas sintesis dengan rasio H2/CO 2,07 dengan yield gas 1,128 mol/mol C (45% konversi karbon). Kata kunci: lignit, pirolisis terkontrol, gasifikasi kukus berkatalis, reaktor unggun tetap

H2-poor bio-syngas in Fischer-Tropsch synthesis over un-promoted and rhenium promoted alumina-supported cobalt catalysts: Effect of water addition Dewi Tristantini; Borje Gevert
ASEAN Journal of Chemical Engineering Vol 9, No 1 (2009)
Publisher : Department of Chemical Engineering, Universitas Gadjah Mada

The effect of water addition on Fischer-Tropsch synthesis (FTS) over 12%Co/Al2O3 and 12%Co-0.5%Re/Al2O3 catalysts was investigated in a fixed bed reactor with model mixtures of biomass-derived syngas (bio-syngas). The bio-syngas model mixtures consist of H2 and CO of different molar H2/CO-ratios (1.0, 1.5 and 2.1). The FT-reaction requires a H2/CO molar ratio of approximately 2.1 above the catalyst surface. For the ratios lower than 2.1, an in situ water-gas shift (WGS) activity is desired in order to increase the H2/CO-ratio. However, the studied catalysts had quite low WGS activities. The addition of water slightly increased the WGS activity for all types of bio-syngases and for both catalysts. The highest WGS activity was found for the un-promoted Co-catalyst at the inlet H2/CO-ratio = 1.0. Water addition also results in an increase in selectivity to C5+ and a decrease in selectivity to CH4 . Interestingly, for both of catalysts the selectivity to C5+ and CH4 were rather similar for inlet H2/CO-ratios of 2.1 and 1.5, while the highest selectivity to C5+ and the lowest selectivity to CH4 were also found for the inlet ratio = 1.0. All catalysts were deactivated by water addition but the catalyst activity is partly recovered in H2/CO-ratio inlets = 1.0 and 1.5. The Co/Al2O3 was affected by water more severely in H2/CO ratios = 2.1. The Re-promoted Co catalyst was considerably more active and selective to longer hydrocarbons than the un- promoted one. The conclusion of this study is that in order to utilize the advantages of a bio-syngas with a low H2 content (higher selectivity to C5+, lower selectivity to CH4, no WGS-unit needed prior to FT-reactor), the catalyst must possess a much higher WGS activity than the ones studied.

Lump Kinetic Analysis of Syngas Composition Effect on Fischer-Tropsch Synthesis over Cobalt and Cobalt-Rhenium Alumina Supported Catalyst Dewi Tristantini; Ricky Kristanda Suwignjo
Bulletin of Chemical Reaction Engineering & Catalysis 2016: BCREC Volume 11 Issue 1 Year 2016 (April 2016)
Publisher : Masyarakat Katalis Indonesia - Indonesian Catalyst Society (MKICS)

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.9767/bcrec.11.1.424.84-92

This study investigated lump kinetic analysis of Fischer-Tropsch synthesis over Cobalt and Cobalt-Rhenium Alumina supported catalyst (Co/γ-Al2O3 and Co-Re/γ-Al2O3) at 20 bars and 483 K using feed gas with molar H2/CO ratios of 1.0 to 2.1. Syngas with H2/CO molar ratio of 1.0 represents syngas characteristic derived from biomass, while the 2.1 molar ratio syngas derived from coal. Rhenium was used as the promoter for the cobalt catalyst. Isothermal Langmuir adsorption mechanism was used to build kinetic model. Existing kinetic model of Fischer-Tropsch synthesis over cobalt alumina supported catalysts only valid for operating pressure less than 10 bar. CO insertion mechanism with hydrogenation step of catalyst-adsorbed CO by catalyst-adsorbed H component as the rate-limiting step is valid for operating condition in this research. Higher H2/CO ratio makes faster hydrogenation step and less-product dominated in the associative CO adsorption step and dissociative H2 adsorption equilibrium step. Kinetic constant for hydrogenation step increases 73-421% in syngas with 2.1 H2/CO molar ratio compared to condition with 1.0 H2/CO molar ratio. Faster hydrogenation step (with higher kinetic constant) results in higher reactant conversion. Equilibrium constant for associative CO adsorption and dissociative H2 adsorption step decreases 53-94% and 13-82%, respectively, in syngas with higher H2/CO molar ratio. Less product dominated reactant adsorption step (lower equilibrium constant for CO and H2 adsorption step) gives higher CH4 product selectivity, which occurred on 2.1 molar ratio of syngas. Rhenium (Re) metal on cobalt catalyst with composition 0.05%Re-12%Co/γ-Al2O3 only gives effect as structural promoter, which only increases reactant conversion with the same product selectivity.

RETRACTED: Uji Aktivitas Ekstrak Bunga Telang (Clitoria ternatea L.) Sebagai Agen Anti-Katarak Eny Kusrini; Dewi Tristantini; Ni’matul Izza
Jurnal Jamu Indonesia Vol. 2 No. 1 (2017): Jurnal Jamu Indonesia
Publisher : Tropical Biopharmaca Research Center, IPB University

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.29244/jji.v2i1.28

Artikel dengan judul Uji Aktivitas Ekstrak Bunga Telang (Clitoria ternatea L.) Sebagai Agen Anti-Katarak telah dilakukan pencabutan dari Jurnal Jamu Indonesia Vol. 2 No. 1 (2017), pada tautan daring http://jamu.journal.ipb.ac.id/index.php/JJI/article/view/28.Pencabutan artikel dilakukan karena permintaan author.Pemberitahuan pencabutan dari artikel tersebut dapat ditemukan pada http://jamu.journal.ipb.ac.id/index.php/JJI/article/view/225.

RETRACTION NOTICE TO: Uji Aktivitas Ekstrak Bunga Telang (Clitoria ternatea L.) Sebagai Agen Anti-Katarak Eny Kusrini; Dewi Tristantini; Ni’matul Izza
Jurnal Jamu Indonesia Vol. 5 No. 3 (2020): Jurnal Jamu Indonesia
Publisher : Tropical Biopharmaca Research Center, IPB University

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.29244/jji.v5i3.225

Artikel dengan judul Uji Aktivitas Ekstrak Bunga Telang (Clitoria ternatea L.) Sebagai Agen Anti-Katarak telah dilakukan pencabutan dari Jurnal Jamu Indonesia Vol. 2 No. 1 (2017), pada tautan daring http://jamu.journal.ipb.ac.id/index.php/JJI/article/view/28.Pencabutan artikel dilakukan karena permintaan author.Pemberitahuan pencabutan dari artikel tersebut dapat ditemukan pada http://jamu.journal.ipb.ac.id/index.php/JJI/article/view/225.

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