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Modified Two-Step Dimethyl Ether (DME) Synthesis Simulation from Indonesian Brown Coal Sasongko, Dwiwahju; Luthan, Abdurrahman Fadhlil Halim; Wulandari, Winny
Journal of Engineering and Technological Sciences Vol 48, No 3 (2016)
Publisher : ITB Journal Publisher, LPPM ITB

A theoretical study was conducted to investigate the performance of dimethyl ether (DME) synthesis from coal. This paper presents a model for two-step DME synthesis from brown coal represented by the following processes: drying, gasification, water-gas reaction, acid gas removal, and DME synthesis reactions. The results of the simulation suggest that a feedstock ratio of coal : oxygen : steam of 1 : 0.13 : 0.821 produces the highest DME concentration. The water-gas reactor simulation at a temperature of 400Â°C and a pressure of 20 bar gave the ratio of H2/CO closest to 2, the optimal value for two-step DME synthesis. As for the DME synthesis reactor simulation, high pressure and low temperature promote a high DME concentration. It is predicted that a temperature of 300Â°C and a pressure of 140 bar are the optimum conditions for the DME synthesis reaction. This study also showed that the DME concentration produced by the two-step route is higher than that produced by one-step DME synthesis, implying that further improvement and research are needed to apply two-step DME synthesis to production of this liquid fuel.

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.

Modified Two-Step Dimethyl Ether (DME) Synthesis Simulation from Indonesian Brown Coal Dwiwahju Sasongko; Abdurrahman Fadhlil Halim Luthan; Winny Wulandari
Journal of Engineering and Technological Sciences Vol. 48 No. 3 (2016)
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.2016.48.3.6

A theoretical study was conducted to investigate the performance of dimethyl ether (DME) synthesis from coal. This paper presents a model for two-step DME synthesis from brown coal represented by the following processes: drying, gasification, water-gas reaction, acid gas removal, and DME synthesis reactions. The results of the simulation suggest that a feedstock ratio of coal : oxygen : steam of 1 : 0.13 : 0.821 produces the highest DME concentration. The water-gas reactor simulation at a temperature of 400°C and a pressure of 20 bar gave the ratio of H2/CO closest to 2, the optimal value for two-step DME synthesis. As for the DME synthesis reactor simulation, high pressure and low temperature promote a high DME concentration. It is predicted that a temperature of 300°C and a pressure of 140 bar are the optimum conditions for the DME synthesis reaction. This study also showed that the DME concentration produced by the two-step route is higher than that produced by one-step DME synthesis, implying that further improvement and research are needed to apply two-step DME synthesis to production of this liquid fuel.

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.

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%.

Analisis Ekonomi Awal Proses Produksi Biobutanol dari Tandan Kosong Sawit dengan Proses Hidrolisis dan Fermentasi Secara Terpisah Reno Susanto; Tjokorde Walmiki Samadhi; Winny Wulandari; Said Zul Amraini
Jurnal Teknik: Media Pengembangan Ilmu dan Aplikasi Teknik Vol 21 No 2 (2022): Jurnal Teknik - Media Pengembangan Ilmu dan Aplikasi Teknik
Publisher : Fakultas Teknik - Universitas Jenderal Achmad Yani

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.55893/jt.vol21no2.447

The limitation of petroleum reserves and environmental issues have led countries worldwide to shift towards producing and utilizing biofuels as an alternative solution to replace fossil fuels. One of the biofuels that can be used is biobutanol, which can be produced from residual waste containing lignocellulose. An empty fruit bunch (EFB) from oil palm is a residual waste used as raw material for biobutanol production. The method that can be used in biobutanol production is the Separated Hydrolysis and Fermentation (SHF) process, which allows the cellulose hydrolysis process to be pre-treated with acid at lower temperature but for longer time or at higher temperature for shorter time. The product from Clostridium acetobutylicum using hydrolysate from cellulose hydrolysis is higher than that from acid hydrolysis. The cellulase enzyme hydrolysis process can be separated from the fermentation process according to their optimum conditions. From the initial economic analysis calculation with production basis of 10,000 tons per year, total gross profit margin of IDR 39,459/kg was obtained, indicating that biobutanol production from EFB biomass is economically feasible and profitable. Further study is needed to conduct a techno-economic analysis of the biobutanol production process using EFB as raw material.

Karakterisasi dan Kinetika Kalsinasi Dolomit Winny Wulandari; Subagjo Subagjo; Adnanta Rio; Pratama Istiadi
Jurnal Teknologi Bahan dan Barang Teknik Vol 8, No 2 (2018)
Publisher : Balai Besar Bahan dan Barang Teknik

Calcination is a key processing step to increase added value of dolomite to many end-products, including as a feedstock for magnesium metal, as a flux for steelmaking, and refractory bricks. This research dealt with calcination of dolomite from Gresik, East Java. Calcination was carried out in a tubular reactor with a diameter of 3 cm, at an atmospheric pressure and using nitrogen as an elusion gas with the rate of 50 mL/min. Reaction temperature was varied at 700, 800 and 900°C and the reactions were carried out for 1, 2, 3, and 4 hours. The conversion of dolomite calcination reaches 98 to 99% as the calcination conducted at 800 and 900°C. The experimental results were presented using various kinetics models. The diffusion Ginstling-Brounshtein model was found as the best for describing the calcination reaction, which implied the reaction was controlled by internal diffusion of reactants. For the Ginstling-Brounshtein model, the apparent activation energy of dolomite calcination was found to be 77.07 kJ/mol.Kalsinasi merupakan salah satu proses untuk meningkatkan nilai tambah dolomit menjadi berbagai jenis produk akhir, seperti bahan baku pembuatan logam magnesium, sebagai fluks untuk pembuatan baja, serta batu bata tahan api. Penelitian ini dimaksudkan untuk menentukan kinetika kalsinasi dolomit Gresik, Jawa Timur. Temperatur reaksi divariasikan 700, 800 dan 900˚C. Kalsinasi dilakukan selama 1, 2, 3, dan 4 jam di dalam sebuah reaktor tubular dengan diameter 3 cm pada tekanan atmosfer. Reaksi kalsinasi dilakukan dalam kondisi gas nitrogen yang dialirkan sebagai gas-elusi dengan laju alir 50 mL/menit. Konversi dolomit mencapai 98 hingga 99% ketika kalsinasi dilakukan pada temperatur 800 dan 900˚C. Model difusi Ginstling-Brounshtein dapat dijadikan model yang paling sesuai untuk menggambarkan reaksi kalsinasi yang dikendalikan oleh perpindahan massa difusi di dalam partikel. Untuk model Ginstling-Brounshtein, energi aktivasi kalsinasi dolomit terhitung sebesar 77,07 kJ/mol.

Investigating the Performance of a 50MW CFB Boiler in a Coal-Fired Power Plant through Co-Firing with Gamal Biomass and RDF Arifta Suryanugraha; Wibawa Hendra Saputera; Winny Wulandari
Journal of Social Research Vol. 4 No. 7 (2025): Journal of Social Research
Publisher : International Journal Labs

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.55324/josr.v4i7.2566

The co-firing program at coal-fired power plants (CFPP) is part of PT PLN (Persero)’s short-term strategy to support Indonesia’s Net Zero Emission (NZE) target by 2060. Biomass and Refuse-Derived Fuel (RDF) are among the promising co-firing fuels. Biomass is considered carbon-neutral, while RDF helps reduce environmental waste. This study evaluates the technical effects of co-firing Gamal and RDF at blending percentages of 5%, 15%, and 30%, focusing on boiler performance and plant efficiency. SteamPRO software by Thermoflow was utilized to simulate and analyze the power plant’s thermodynamic performance under each co-firing condition. The simulations show that fuel specification or fuel composition and calorific value significantly affect key performance parameters. Co-firing with Gamal increases the Net Plant Heat Rate (NPHR) from 3034 kcal/kWh (baseline) to 3065, 3136, and 3264 kcal/kWh for 5%, 15%, and 30% co-firing, respectively. Plant efficiency correspondingly declines from 28.35% to 28.05%, 27.42%, and 26.35%. Boiler efficiency also drops from 83.69% to 82.98%, 81.47%, and 78.92%. RDF, in comparison, results in smaller deviations, with NPHR reaching only 3062 kcal/kWh and plant efficiency decreasing slightly to 28.08% at 30% co-firing. The lower calorific value of Gamal (2481 kcal/kg) increases the total fuel flow and raises auxiliary power consumption in the draught system, especially in the PA, SA, and ID fans, whereas RDF causes only minimal deviations. Emission results show that Gamal, with 0.07% sulfur, reduces SO? emissions from 0.474 to 0.4326 kg/MWh at 30% co-firing, while RDF increases it to 0.4905 kg/MWh due to higher sulfur content (0.42%). Uncorrected CO? emissions rise with Gamal but decrease after applying the carbon-neutral factor, from 984 to 730 kg/MWh at 30%. These results emphasize the importance of co-firing fuel specification selection and blending percentage optimization to balance performance and environmental outcomes.

DEVELOPMENT OF BIO-BASED PRESSURE-SENSITIVE ADHESIVE FORMULATIONS DERIVED FROM ROSIN ESTERS USING MIXTURE DESIGN METHODOLOGY Mardiah Mardiah; Aqsha Aqsha; Tjokorde Walmiki Samadhi; Winny Wulandari; Antonius Indarto
Jurnal Teknologi Lingkungan UNMUL Vol 10, No 1 (2026): Jurnal Teknologi Lingkungan UNMUL
Publisher : Mulawarman University Press

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.30872/jtlunmul.v10i1.27695

Pressure-sensitive adhesives (PSAs) are commonly used in medical, packaging and industrial applications. Nevertheless, conventional petroleum-based adhesives raise concerns about sustainability, environmental impact and dependence on non-renewable resources. The objective of this study was to synthesize an eco-friendly bio-based pressure-sensitive adhesive from rosin ester by using simplex lattice design (SLD) methodology. The adhesive formulation was comprised of glycerol rosin ester, polyethylene glycol (PEG) rosin ester, lecithin, polyvinyl alcohol (PVA) and borax as cross linking agent. Adhesive performance was evaluated by peel strength, holding power and cohesion analysis. The result indicated that formulations with greater concentrations of glycerol rosin ester showed better adhesive properties with peel strength 0.8 N/cm and holding power 800 s. The optimum formulation by SLD optimization was 9 parts glycerol rosin ester, 7 parts PEG rosin ester and 4 parts lecithin. The proposed bio-based adhesive has not yet exceeded the performance of acrylic-based pressure-sensitive adhesive. However, it demonstrated adequate performance for lightweight labeling. In addition, renewable rosin-based raw materials provide a sustainable option to petroleum-derived adhesives, reducing dependence on fossil resources and driving the growth of green adhesive materials.

Model Validation of Biomass-Coal Blends Co-Pyrolysis to Produce Hybrid Coal Aghietyas Choirun Az Zahra; Hendi Aviano Prasetyo; Jenny Rizkiana; Winny Wulandari; Dwiwahju Sasongko
Indonesian Journal of Energy Vol. 2 No. 2 (2019): Indonesian Journal of Energy
Publisher : Purnomo Yusgiantoro Center

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.33116/ije.v2i2.41

Co-pyrolysis of coal and biomass blend to produce hybrid coal has recently been experimentally studied by some previous researchers. For similar generated energy, a newly developed hybrid coal is claimed to be more environmentally friendly compared to the coal only due to the release of neutral CO2. To acquire a better understanding of co-pyrolysis of coal and biomass blend, an experiment had been carried out in a tubular furnace reactor. For this purpose, the blends of constant mass composition of 20 wt% sawdust and 80 wt% low-rank coal were used throughout the study. It was found from the experiment that approximately 42.1% carbon, and 1.6% of ash were produced from the co-pyrolysis blend. Then, a steady state simulation of co-pyrolysis was developed using Aspen Plus v8.8 to predict the hybrid coal carbon content and required heat to perform the co-pyrolysis. The model simulation showed that hybrid coal yielded 44.0% carbon, which was at 4.5% deviation from the experimental study. The model had also been successfully used to estimate heat required to produce hybrid coal. It predicted that the equivalent heat of 336.2 kW was required to produce hybrid coal from 1,000 kg/h blend feed. The heat generated by the modeling of sawdust biomass combustion for fuel purposes was also estimated to supply heat for endothermic co-pyrolysis. It was found that 1,000 kg/h sawdust was predicted to be equivalent to 371.4 kW. This suggests that for scaling up purpose, ratio of sawdust fuel to blend feed of 1:1.1 is sufficient for this process.

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