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TORREFACTION OF RUBBERWOOD WASTE: THE EFFECTS OF PARTICLE SIZE, TEMPERATURE & RESIDENCE TIME Wulandari, Winny; Jahsy, Nursayyidah Ainun; Tandias, Adrian Hartanto; Rizkiana, Jenny; Rubani, Inga Shaffira; Saputera, Wibawa Hendra; Sasongko, Dwiwahju
Journal of Engineering and Technological Sciences Vol 52, No 2 (2020)
Publisher : Institute for Research and Community Services, Institut Teknologi Bandung

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.5614/j.eng.technol.sci.2020.52.2.1

Agriculture waste has created massive challenges over the last few decades and yet also opportunities. This work aimed to produce high-quality biochar from rubberwood waste with calorific properties close to subbituminous coal. Using a tubular vertical reactor, the effects of rubberwood particle size (wood chips and shredded wood), torrefaction temperature (220, 260, and 300 °C), and residence time (30, 60, and 90 minutes) on the quality of torrefied rubberwood were studied. The results showed that the mass loss of the rubberwood increased as the temperature increased. Also, the particle size and residence time increased due to excessive devolatilization. A higher fixed-carbon content and calorific value as well as lower moisture and volatile-matter content were achieved by increasing the torrefaction temperature and residence time in comparison to the untreated sample (raw rubberwood). The highest fixed-carbon content and calorific value were found to be 56.7% and 6313 kcal/kg, respectively, for the wood chip particles that were torrefied at 300 °C for 60 minutes. Based on the Van Krevelen diagram, torrefaction of woodchip rubberwood at 300 °C with a residence time of 60 minutes demonstrated the optimum condition to generate a product with properties that are close to those of subbituminous rank coal.

Synthesis and Characterization of Hydrochar and Bio-oil from Hydrothermal Carbonization of Sargassum sp. using Choline Chloride (ChCl) Catalyst Rustamaji, Heri; Prakoso, Tirto; Rizkiana, Jenny; Devianto, Hary; Widiatmoko, Pramujo; Guan, Guoqing
International Journal of Renewable Energy Development Vol 11, No 2 (2022): May 2022
Publisher : Center of Biomass & Renewable Energy, Diponegoro University

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.14710/ijred.2022.42595

The purpose of this study is to alter the biomass of Sargassum sp. into elective fills and high valuable biomaterials in a hydrothermal process at 200oC for 90 minutes, using ZnCl2 and CaCl2 activating agents, withChClas a catalyst. This method generatedthree primaryoutputs: hydrochar, bio-oil, and gasproducts. ChCl to water ratio varies from 1:3, 1:1, and 3:1. The hydrochar yield improved when the catalyst ratio was increased, but the bio-oil and gas yield declined. The highest hydrochar yields were 76.95, 63.25, and 44.16 percent in ZnCl2, CaCl2, and no activating agent samples, respectively.The porosity analysis observed mesopore structures with the most pore diameters between 3.9-5.2 nm with a surface area betweenÂ 44.71-55.2. The attribute of interaction between activator and catalyst plays a role in pore formation. The hydrochar products with CaCl2 showed the best thermal stability. From the whole experiment, the optimum hydrochar yield (76.95%), optimum surface area (55.42 m2 g-1), and the increase in carbon content from 21.11 to 37.8% were achieved at the ratio of ChCl to water was three, and the activating agent of ZnCl2. The predominant bio-oil components were hexadecane, hexadecanoic, and 9-octadecenoic acids, with a composition of 51.65, 21.44, and 9.87%, respectively the remaining contained aromatic alkanes and other fatty acids. The findings of this study reported that adding activating agents and catalysts improve hydrochar yield and characteristics of hydrochar and bio-oil products, suggesting the potential of hydrochar as a solid fuel or biomaterial and bio-oil as liquid biofuel

Simulation and optimization of coupling reaction of methanol synthesis and isopropyl alcohol dehydrogenation Jenny Rizkiana; Yogi Wibisono Budhi; Azis Trianto
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.2011.10.3.3

A study on simulation and optimization of coupling reaction between methanol synthesis and isopropyl alcohol (IPA) dehydrogenation was performed. The analysis is carried out theoretically to obtain the optimum operation conditions which give the best performance. The reactions are just interacting thermally. In this study, both reactions are held catalytically in a heat-exchanger type reactor. As a high pressure reaction, methanol synthesis is placed in the inner side of reactor tube while dehydrogenation of IPA is in the opposite. Tube wall acts as a heat transfer media. The reactor is modeled by a steady state heterogeneous equation for a fixed bed reactor. Optimization is done in order to find the optimum value of operation conditions, those are the inlet temperature of both side of reactor and the molar feed flow ratio between the exothermic side and the endothermic side. Sum of weighted reaction conversion is considered to be the objective function that is maximized. The simulation result shows that coupled reactor makes the reaction conversion higher than a conventional adiabatic reactor and the optimum operation conditions give the maximum value of the conversion. This study presents a theoretical proof that coupling reaction is feasible. Keywords: coupling reaction, IPA dehydrogenation, methanol synthesis, optimization, simulated annealingAbstrak Telaah mengenai simulasi dan optimisasi reaksi perangkaian (coupling reaction) antara sintesis metanol dengan dehidrogenasi isopropil alkohol (IPA) telah dilakukan. Analisis dilaksanakan secara teoretik guna mendapatkan kondisi optimum yang akan memberikan hasil terbaik. Pada penelitian ini, kedua reaksi dilaksanakan secara katalitik dalam reaktor bertipe buluh-cangkang. Karena bertekanan tinggi, sintesis metanol ditempatkan pada sisi buluh, sedangkan dehidrogenasi IPA ditempatkan pada sisi cangkang. Dinding buluh berperan sebagai media perpindahan panas. Reaktor dimodelkan dengan reaktor heterogen tunak unggun tetap. Optimisasi dilakukan dalam rangka mendapatkan nilai optimum dari kondisi operasi yang mencakup temperatur inlet sisi eksotermik dan endotermik serta rasio umpan molarnya. Jumlah total konversi reaksi terbobotkan dipilih sebagai nilai objectif yang akan dioptimumkan. Hasil simulasi menunjukkan bahwa reaktor perangkaian termal mampu meningkatkan konversi reaksi jika dibandingkan dengan reaktor adiabatik dan pada kondisi operasi yang optimum diperoleh konversi maksimal. Penelitian ini menunjukkan bahwa reaksi perangkaian layak untuk dilaksanakan.Kata kunci: reaksi perangkaian, dehidrogenasi IPA, sintesis methanol, optimisasi, simulated annealing

Torrefaction of Rubberwood Waste: The Effects of Particle Size, Temperature & Residence Time Winny Wulandari; Nursayyidah Ainun Jahsy; Adrian Hartanto Tandias; Jenny Rizkiana; Inga Shaffira Rubani; Wibawa Hendra Saputera; Dwiwahju Sasongko
Journal of Engineering and Technological Sciences Vol. 52 No. 2 (2020)
Publisher : Institute for Research and Community Services, Institut Teknologi Bandung

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.5614/j.eng.technol.sci.2020.52.2.1

Agriculture waste has created massive challenges over the last few decades and yet also opportunities. This work aimed to produce high-quality biochar from rubberwood waste with calorific properties close to subbituminous coal. Using a tubular vertical reactor, the effects of rubberwood particle size (wood chips and shredded wood), torrefaction temperature (220, 260, and 300 °C), and residence time (30, 60, and 90 minutes) on the quality of torrefied rubberwood were studied. The results showed that the mass loss of the rubberwood increased as the temperature increased. Also, the particle size and residence time increased due to excessive devolatilization. A higher fixed-carbon content and calorific value as well as lower moisture and volatile-matter content were achieved by increasing the torrefaction temperature and residence time in comparison to the untreated sample (raw rubberwood). The highest fixed-carbon content and calorific value were found to be 56.7% and 6313 kcal/kg, respectively, for the wood chip particles that were torrefied at 300 °C for 60 minutes. Based on the Van Krevelen diagram, torrefaction of woodchip rubberwood at 300 °C with a residence time of 60 minutes demonstrated the optimum condition to generate a product with properties that are close to those of subbituminous rank coal.

Volatile State Mathematical Models for Predicting Components in Biomass Pyrolysis Products Pandit Hernowo; Carolus B. Rasrendra; Yogi W. Budhi; Jenny Rizkiana; Anton Irawan; Septhian Marno; Yana Meliana; Oki Muraza; Yazid Bindar
Journal of Engineering and Technological Sciences Vol. 54 No. 1 (2022)
Publisher : Institute for Research and Community Services, Institut Teknologi Bandung

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.5614/j.eng.technol.sci.2022.54.1.8

Volatile state mathematical models for quantifying the chemical components in volatile biomass pyrolysis products were developed. The component mass yield Yi rate depends linearly on its pseudo kinetic constant and the remaining mass yield. The mass fraction rate of each component was modeled from the derivation of its mass yield rate equation. A new mathematical model equation was successfully developed. The involved variables are: biomass number, temperature, heating rate, pre-exponential factor, and pseudo activation energy related to each component. The component mass fraction yi and the mass yield were predicted using this model within a temperature range. Available experimental pyrolysis data for beechwood and rice husk biomass were used to confirm the developed model. The volatile products were separated into bio-pyrolysis gas (BPG) and a bio-pyrolysis oil (BPO). Five components in the BPG and forty in the BPO were quantified. The pseudo activation energy for each pseudo chemical reaction for a specific component was modeled as a polynomial function of temperature. The component mass fraction and yield are quantifiable using this developed mathematical model equation within a temperature range. The predicted component mass fractions and yields agreed excellently with the available experimental data.

Evaluation on Energy Efficiency Improvement in Geothermal Power Plant with The Application of Load-based Gas Removal System and Cooling Water Pump Control System Wibisono Yamin; I.G.B Ngurah Makertihartha; Jenny Rizkiana
Jurnal Rekayasa Proses Vol 14, No 1 (2020)
Publisher : Departemen Teknik Kimia Fakultas Teknik Universitas Gadjah Mada

Efficient Geothermal Power Plant (GPP) operation can be achieved through the optimum use of steam for turbine and auxiliary (ejectors), and minimum possible condenser pressure for maximum energy conversion in the turbine. In all GPPs, a condenser vacuum is maintained by adequate circulation of cooling water and effective operation of ejectors, which absorb the accumulation of Non-Condensable Gas (NCG), mostly CO2 and H2S, and dispose it to the atmosphere. Typically, GPPs are designed for baseload (100% capacity) operation. Therefore, the performance of supporting equipment such as ejectors and cooling water pumps are not sensitive to load-set fluctuations or changes in NCG content. This fact consequently results in constant parasitic load and ejector's motive steam consumptions. Since 2017 many GPPs in Indonesia have no longer operated at constant full capacity following demand fluctuation, as stated in grid dispatcher's Daily Operating Plan. This condition brings up energy efficiency opportunity to reduce steam and electricity own use through modification or installation of the load-following controller in the ejector system and cooling water pumps. The study aimed to identify the best alternative in devising this adaptive feature in gas removal and circulating water systems from economic and technical aspects. Evaluation's methodology included the development of GPP process modeling and data validation, setting up an alternative framework, testing of GPP performance for each alternative with the calibrated model, and decision analysis from economic and technical aspects to select the best option. The evaluation showed that the ejector's motive steam flow controller was able to reduce auxiliary steam usage at maximum by 7% (equal to 0.7 MWe). In comparison, the circulation water flow controller with Variable Frequency Drive (VFD) could reduce pumps electricity use by 35% (0.76 MWe). The study results recommended the implementation of a motive steam flow controller over the pump's VFD, considering its economic performance, operation flexibility, and lower execution risk. A B S T R A KOperasi Pembangkit Listrik Tenaga Panas Bumi (PLTP) yang efisien dapat dicapai melalui penggunaan uap yang optimal pada turbin dan sistem pendukung (ejektor), serta pengaturan tekanan kondensor yang rendah untuk mencapai konversi energi maksimum di turbin. Pada hampir semua PLTP, kevakuman kondensor dijaga melalui sirkulasi air pendingin yang memadai, dan efektivitas operasi ejektor dalam menghisap akumulasi Non-Condensable Gas (NCG), yaitu CO2, dan H2S, serta dispersinya ke atmosfer. Pada umumnya PLTP didesain untuk beroperasi pada basis bebannya (100% kapasitas) sehingga kinerja peralatan penunjang seperti ejektor dan pompa tidak sensitif terhadap fluktuasi beban pembangkitan maupun perubahan kandungan NCG dari sumur. Hal ini mengakibatkan pemakaian listrik sendiri dan konsumsi uap ejektor pada PLTP cenderung tetap. Sejak 2017 banyak PLTP di Indonesia tidak lagi beroperasi dengan kapasitas penuh karena mengikuti fluktuasi permintaan grid seperti yang dinyatakan dalam Rencana Operasi Harian dari pengatur beban. Kondisi ini memberi peluang upaya efisiensi energi untuk mengurangi konsumsi listrik dan uap melalui modifikasi dan instalasi pengontrol load-following pada sistem kerja ejektor dan pompa sirkulasi air pendingin. Studi ini bertujuan untuk mengidentifikasi alternatif terbaik dalam merancang fitur adaptif ini, baik dari aspek ekonomi maupun teknis. Metodologi evaluasi mencakup pengembangan pemodelan proses PLTP dan validasi datanya, menyiapkan kerangka evaluasi alternatif, pengujian kinerja PLTP untuk setiap alternatif dengan model yang terkalibrasi, dan analisis pemilihan opsi terbaik secara ekonomi dan teknis. Hasil evaluasi menunjukkan bahwa pengontrol aliran uap motif pada ejektor mampu mengurangi penggunaan uap maksimum sebesar 7% (setara 0,7 MWe), sedangkan pengontrol aliran air sirkulasi dengan Variable Frequency Drive (VFD) dapat mengurangi penggunaan pompa listrik sebesar 35% (0,76 MWe). Hasil studi merekomendasikan penerapan sistem pengontrol aliran uap motif pada ejektor dibandingkan aplikasi VFD pada pompa dengan mempertimbangkan kinerja ekonomi, fleksibilitas operasi, dan risiko eksekusinya yang lebih rendah.

KARBONISASI LIMBAH KELAPA SAWIT DENGAN PROSES HIDROTERMAL SEBAGAI BAHAN BAKU ELEKTRODA SUPERKAPASITOR Tantra Diwa Larasati; Tirto Prakoso; Jenny Rizkiana
Jurnal Chemurgy Vol 5, No 1 (2021): Jurnal Chemurgy-Juni 2021
Publisher : Universitas Mulawarman

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.30872/cmg.v5i1.5916

Limbah kelapa sawit merupakan sumber biomassa yang melimpah di Indonesia. Ketersediaan biomassa kelapa sawit ini dapat dimanfaatkan sebagai bahan baku produk bernilai tambah tinggi. Salah satu produk yang dapat dihasilkan adalah karbon aktif. Karbon aktif merupakan material berpori dan memiliki konduktivitas yang baik, membuat karbon aktif cocok digunakan sebagai material elektroda superkapasitor. Karbon aktif dibuat melalui dua proses utama yaitu karbonisasi dan aktivasi. Proses karbonisasi yang dilakukan adalah karbonisasi hidrotermal dilanjutkan dengan aktivasi secara fisika. Penelitian ini difokuskan pada pembuatan karbon aktif berbasis limbah kelapa sawit dengan proses karbonisasi hidrotermal untuk bahan baku superkapasitor. Mesopore area dari karbon aktif terbentuk akibat penggunaan CaCl2 sebagai agen pengaktivasi selama proses hidrotermal. Karbon aktif yang dihasilkan dari tandan kosong kelapa sawit memiliki luas permukaan 375 – 723 m2/g dan ukuran pori 3,4 – 5,6 nm. Pada penelitian ini, karbon aktif digunakan sebagai elektroda kerja pada superkapasitor tipe hybrid simetrikal. Sel superkapasitor ini mampu menghasilkan kapasitansi sebesar 4,3015 F/g.

Evaluation on Energy Efficiency Improvement in Geothermal Power Plant with The Application of Load-based Gas Removal System and Cooling Water Pump Control System Wibisono Yamin; I.G.B Ngurah Makertihartha; Jenny Rizkiana
Jurnal Rekayasa Proses Vol 14, No 1 (2020)
Publisher : Departemen Teknik Kimia Fakultas Teknik Universitas Gadjah Mada

Efficient Geothermal Power Plant (GPP) operation can be achieved through the optimum use of steam for turbine and auxiliary (ejectors), and minimum possible condenser pressure for maximum energy conversion in the turbine. In all GPPs, a condenser vacuum is maintained by adequate circulation of cooling water and effective operation of ejectors, which absorb the accumulation of Non-Condensable Gas (NCG), mostly CO2 and H2S, and dispose it to the atmosphere. Typically, GPPs are designed for baseload (100% capacity) operation. Therefore, the performance of supporting equipment such as ejectors and cooling water pumps are not sensitive to load-set fluctuations or changes in NCG content. This fact consequently results in constant parasitic load and ejector's motive steam consumptions. Since 2017 many GPPs in Indonesia have no longer operated at constant full capacity following demand fluctuation, as stated in grid dispatcher's Daily Operating Plan. This condition brings up energy efficiency opportunity to reduce steam and electricity own use through modification or installation of the load-following controller in the ejector system and cooling water pumps. The study aimed to identify the best alternative in devising this adaptive feature in gas removal and circulating water systems from economic and technical aspects. Evaluation's methodology included the development of GPP process modeling and data validation, setting up an alternative framework, testing of GPP performance for each alternative with the calibrated model, and decision analysis from economic and technical aspects to select the best option. The evaluation showed that the ejector's motive steam flow controller was able to reduce auxiliary steam usage at maximum by 7% (equal to 0.7 MWe). In comparison, the circulation water flow controller with Variable Frequency Drive (VFD) could reduce pumps electricity use by 35% (0.76 MWe). The study results recommended the implementation of a motive steam flow controller over the pump's VFD, considering its economic performance, operation flexibility, and lower execution risk. A B S T R A KOperasi Pembangkit Listrik Tenaga Panas Bumi (PLTP) yang efisien dapat dicapai melalui penggunaan uap yang optimal pada turbin dan sistem pendukung (ejektor), serta pengaturan tekanan kondensor yang rendah untuk mencapai konversi energi maksimum di turbin. Pada hampir semua PLTP, kevakuman kondensor dijaga melalui sirkulasi air pendingin yang memadai, dan efektivitas operasi ejektor dalam menghisap akumulasi Non-Condensable Gas (NCG), yaitu CO2, dan H2S, serta dispersinya ke atmosfer. Pada umumnya PLTP didesain untuk beroperasi pada basis bebannya (100% kapasitas) sehingga kinerja peralatan penunjang seperti ejektor dan pompa tidak sensitif terhadap fluktuasi beban pembangkitan maupun perubahan kandungan NCG dari sumur. Hal ini mengakibatkan pemakaian listrik sendiri dan konsumsi uap ejektor pada PLTP cenderung tetap. Sejak 2017 banyak PLTP di Indonesia tidak lagi beroperasi dengan kapasitas penuh karena mengikuti fluktuasi permintaan grid seperti yang dinyatakan dalam Rencana Operasi Harian dari pengatur beban. Kondisi ini memberi peluang upaya efisiensi energi untuk mengurangi konsumsi listrik dan uap melalui modifikasi dan instalasi pengontrol load-following pada sistem kerja ejektor dan pompa sirkulasi air pendingin. Studi ini bertujuan untuk mengidentifikasi alternatif terbaik dalam merancang fitur adaptif ini, baik dari aspek ekonomi maupun teknis. Metodologi evaluasi mencakup pengembangan pemodelan proses PLTP dan validasi datanya, menyiapkan kerangka evaluasi alternatif, pengujian kinerja PLTP untuk setiap alternatif dengan model yang terkalibrasi, dan analisis pemilihan opsi terbaik secara ekonomi dan teknis. Hasil evaluasi menunjukkan bahwa pengontrol aliran uap motif pada ejektor mampu mengurangi penggunaan uap maksimum sebesar 7% (setara 0,7 MWe), sedangkan pengontrol aliran air sirkulasi dengan Variable Frequency Drive (VFD) dapat mengurangi penggunaan pompa listrik sebesar 35% (0,76 MWe). Hasil studi merekomendasikan penerapan sistem pengontrol aliran uap motif pada ejektor dibandingkan aplikasi VFD pada pompa dengan mempertimbangkan kinerja ekonomi, fleksibilitas operasi, dan risiko eksekusinya yang lebih rendah.

Hybrid Coal: Effects Of Composition And Co-pyrolysis Retention Time in Low Rank Coal and Biomass Waste Co-pyrolysis Process on The Product’s Yield Jenny Rizkiana; Slamet Handoko; Winny Wulandari; Muhammad Afif Ridha; Hendi Aviano Prasetyo; Dwiwahju Sasongko
ASEAN Journal of Chemical Engineering Vol 18, No 1 (2018)
Publisher : Department of Chemical Engineering, Universitas Gadjah Mada

Low rank coal upgrading into a more efficient and environmentally friendly fuel can be done through copyrolysis with biomass into a fuel called hybrid coal. The purpose of the research is to determine the effects of biomass composition and copyrolysis retention time to the hybrid coal yields. Copyrolysis process conducted in a vertical tubular fixed bed reactor in an inert condition with atmospheric pressure and temperature set at 300oC. Inert condition achieved by flowing nitrogen gas into the reactor with a flowrate of 1.6 L/minutes. Biomass mixing composition is varied at 20, 30, and 40% from the total weight of the mixture. Copyrolysis retention time varied at 30, 60, and 90 minutes. Hybrid coals are characterized by proximate analysis, ultimate analysis, and calorific value measurement. Increase in retention time of copyrolysis from 30 to 90 minutes causing an increase in calorific value of 12.57-23.80%. From the proximate analysis results, fixed carbon content rise with the increase of co-pyrolysis time. The highest fixed carbon content obtained in the variation of 90 minutes, in the range of 49.36-49.75%. Increasing of sawdust composition from 20 to 40%, lowering the calorific value in the range of 0.58-8.55%.

Effect of Pressure and Syngas Composition on Direct Synthesis of Dimethyl Ether using Dual Bed Catalyst Aisyah Ardy; Jenny Rizkiana; Melia Laniwati Gunawan; Herri Susanto
ASEAN Journal of Chemical Engineering Vol 19, No 1 (2019)
Publisher : Department of Chemical Engineering, Universitas Gadjah Mada

National General Energy Plan of Indonesia 2017 (RUEN 2017) stated that dimethyl ether (DME) is appointed as a blending of LPG to reduce LPG imports. DME can be made with two reaction pathways, namely direct synthesis and indirect synthesis. The objective of this study was to determine the effect of pressure and syngas composition on the direct synthesis of DME using dual fixed bed catalyst. The research was carried out with two types of catalyst: M-xxx as a commercial catalyst for methanol synthesis and γ-Al2O3 as catalyst for dehydration of methanol to DME. The later was prepared in our Laboratory of Chemical Reaction Engineering and Catalysis, ITB. The dual catalyst experiment was carried out at 5 and 7 bars, and a fixed temperature of 240oC. The mass ratio of the M-xxx to γ-Al2O3, so-called M/D ratios, were varied from 1/9 to 9/1. Two type of syngas were used, i.e. SA containing only H2 and CO with a SN of 2,3 and SB containing 4% CO2 with SN of 1,8. The dual bed with a M/D ratio of 1/4 gave a CO conversion up to 62% at 5 bars and 240oC (SA). As pressure increased, the conversion of CO and H2 increases to 85% and 83% at 7 bar and 240oC (SA). The presence of CO2 (SB) decreases catalyst activity, as indicated by the decrease in conversion of CO and H2 to 56% and 54%, at 7 bar and 240oC.

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