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All Journal Jurnal Teknik ITS Journal of Engineering and Technological Sciences JMES The International Journal of Mechanical Engineering and Sciences
Bambang Arip Dwiyantoro
Institut Teknologi Sepuluh Nopember
Energy Engineering Materials Science & Nanotechnology Mechanical Engineering

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Analisa Heat Balance Thermal Oxidizer dengan Waste Heat Recovery Unit Alfian Bani Susiloputra; Bambang Arip Dwiyantoro
Jurnal Teknik ITS Vol 6, No 1 (2017)
Publisher : Direktorat Riset dan Pengabdian Masyarakat (DRPM), ITS

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (746.206 KB) | DOI: 10.12962/j23373539.v6i1.22384

Abstract

Central Processing Plant (CPP) merupakan plant yang memproses feed gas hingga menjadi natural gas siap pakai. Pengolahan feed gas di CPP menimbulkan dampak limbah berupa waste gas. Thermal Oxidizer (TOX) memiliki peran penting dalam mengatasi waste gas. Energi panas gas buang (flue gas) dimanfaatkan pada Waste Heat Recovery Unit (WHRU) yang berada diatas chamber, digunakan untuk memanaskan hot oil. Kondisi operasional pembakaran TOX di CPP saat ini, jumlah input sangat berbeda dengan desain awal. Suhu pembakaran juga sangat tinggi, yaitu diatas 1.144 K. Sementara itu WHRU belum berjalan secara normal, suhu hot oil pada outlet WHRU masih 438-444 K. Analisa pembakaran TOX dilakukan dengan analisa termodinamika pada jumlah bahan bakar serta jumlah excess air untuk mendapatkan pembakaran sempurna pada suhu ideal chamber, yaitu 1.088-1.144 K. Bahan bakar yang digunakan sejumlah 60%-100% dari fuel gas operasional, sedangkan excess air yang digunakan 10%-35%. Selain itu pemanfaatan energi panas flue gas pada WHRU dilakukan analisa supaya suhu hot oil keluar WHRU mencapai 449 K. Analisa WHRU dilakukan dengan analisa perpindahan panas, untuk mendapatkan flowrate dari hot oil dari suhu dan laju aliran massa flue gas hasil variasi pembakaran TOX tersebut. Dari penelitian ini, suhu TOX hasil pembakaran operasional yang sesuai dengan desain awal yaitu pada 60% fuel gas dengan excess air (EA) antara 30% hingga 35%. Pada 60% fuel gas dengan EA antara 30% hingga 35% didapatkan suhu antara 1.095 K hingga 1.138 K. Pada hasil analisa WHRU, untuk mencapai suhu hot oil sebesar 449,817 K pada variasi TOX tersebut diperlukan laju aliran massa hot oil sebesar 1.257.720 kg/jam dan 1.481.420 kg/jam.
Analisa Pengaruh Variasi Pinch Point dan Approach Point terhadap Performa HRSG Tipe Dual Pressure Ryan Hidayat; Bambang Arip Dwiyantoro
Jurnal Teknik ITS Vol 6, No 1 (2017)
Publisher : Direktorat Riset dan Pengabdian Masyarakat (DRPM), ITS

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (743.993 KB) | DOI: 10.12962/j23373539.v6i1.22474

Abstract

Siklus kombinasi adalah siklus termodinamika yang menggabungkan siklus Rankine dan siklus Brayton dengan komponen HRSG sebagai penghubung. Untuk mendapat rancangan HRSG yang baik, maka perlu untuk mengetahui pengaruh parameter internal maupun eksternal dari HRSG. Parameter yang ditinjau adalah pinch point dan approach point, juga perubahan beban turbin gas. Dengan menggunakan perangkat lunak cycle tempo, simulasi pembangkit dengan konfigurasi 1x1x1 dilakukan. Hasil yang didapat dari simulasi adalah nilai net power output, net plant efficiency, dan net plant heat rate dengan variasi parameter yang telah disebutkan. Setelah simulasi dilakukan, pada beban turbin gas 100% didapatkan hasil berupa nilai net power output sebesar 72,205 MW yang mengalami penurunan, juga net plant efficiency 47,044%, dan net plant heat rate 7652,3 kJ/kWh yang tetap seiring menurunnya beban turbin. Sementara untuk variasi pinch point dan approach point akan mengakibatkan power output, dan net plant efficiency meningkat, dan net plant heat rate menurun seiring dengan berkurangnya nilai kedua parameter tersebut. Variasi yang menghasilkan performa terbaik adalah pada pengurangan nilai pinch point modul low pressure dimana pinch point sebesar 50,8o C dan approach point 9,77o C menghasilkan power sebesar 16,069 MW, net plant efficiency sebesar 50,462 %, dan net plant heat rate sebesar 7132,535 kJ/kWh, namun untuk dapat membangkitkan daya sebesar itu diperlukan tambahan sumber panas sebesar 25 MW.
The Influence of Cross-Sectional Shape and Orientation of Micropillar Surface on Microdroplet Formation by a Dewetting Process Bambang Arip Dwiyantoro; Shiu-Wu Chau
Journal of Engineering and Technological Sciences Vol. 45 No. 2 (2013)
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.2013.45.2.5

Abstract

In this study the dewetting process on micropillars of three different cross-sectional shapes, i.e. circular, square and triangular, was numerically investigated. The influence of the orientation of the triangular and square micropillars on the dewetting behavior was also studied. The numerical simulations showed that the cross-sectional shapes of the micropillars and their orientation play an important role in determining the flow pattern of the dewetting process, especially the evolution and movement of the meniscus across the micropillar before a microdroplet is formed. The diameter of the microdroplets is mainly determined by the capillary effect, viscous drag and fluid inertia contributed by the peeling rate and the thickness of the water layer above the micropillar. The numerical results also indicate that the hydraulic diameter of the micropillars (Dp) is one of the parameters governing the size of the microdroplets formed on the top surface of the micropillars after the dewetting process, while the microdroplet diameter is almost insensitive to the cross-sectional shape and orientation of the micropillars. The dimensionless diameter of the microdroplets (d) can then be expressed as a function of a dimensionless group, i.e. the Ohnesorge number (Oh), the capillary number (Ca), the dimensionless liquid thickness (H), and the contact angle (q).
Study of Coal Drying Characteristics Using Boiler Blowdown in a Rotary Coal Dryer Aripin Gandi Marbun; Bambang Arip Dwiyantoro; Alvin Mizrawan Tarmizi
JMES The International Journal of Mechanical Engineering and Sciences Vol 6, No 1 (2022)
Publisher : LPPM, Institut Teknologi Sepuluh Nopember, Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.12962/j25807471.v6i1.12053

Abstract

Drying lignite coal to reduce its moisture content has become popular in the last decade. Previously, coal dryers used typical energy such as steam, fuel, or electrical as heat sources. Waste energy had never been implemented in a coal dryer while using it would reduce the cost of production and raise the economic value of the coal itself. An experimental study of drying low-rank coal was conducted using waste energy boiler blowdown in a rotary coal dryer. With variations of 0.595 mm, 1.18 mm, and 4.75 mm coal particle size and the flow's changes of 20 kg/hour, 30 kg/hour, and 40 kg/hour. The hot air temperature of 70oC, mass flow rate of 36 kg/hour, and pressure of 0,03 MPa were the constant parameters on the 15 rpm rotary drum. The results found that the coal moisture decreased significantly at 0.595 mm particle size and 20 kg/hour of flow. The final coal moisture dropped by 20.685%, and the calorific value increased by 879.6 kcal/kg from its initial value. In addition, the efficiency of the rotary coal dryer is 81.8%.
Optimization Design Analysis of Boiler Blowdown Utilization on A Rotary Coal Dryer with Drum Tilt Angle Variations Alvin Mizrawan Tarmizi; Bambang Arip Dwiyantoro; Aripin Gandi Marbun
JMES The International Journal of Mechanical Engineering and Sciences Vol 6, No 1 (2022)
Publisher : LPPM, Institut Teknologi Sepuluh Nopember, Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.12962/j25807471.v6i1.12046

Abstract

Lignite coal has dominated the use of steam power plants in recent years. Despite the consequences, which cause many problems, lignite is cheap and easy to obtain. One of the problems was mitigated by reducing the moisture content using a rotary coal dryer. Coal dryer is deemed uneconomical with the current energy sources from turbine extraction steam, electric heaters, and exhaust gas using large-powered fans. The waste energy from boiler blowdown, a water-vapored fluid discharged from the boiler to maintain water and steam quality, is being conducted to improve. Blowdown investigated in a rotary coal dryer type. The compressed air absorbed the heat from the blowdown through the steam coil. The hot air mixed with the coal in the rotary drum. A rotary drum was tested with the tilt angles of 0°, 10°, 20°, 30°, 40°, 50°, 60°, 70°, 80°, and 90°. The research steps were designing, preliminary modeling, numerical analysis, prototyping, and experimental performing. The result shows that the moisture content has decreased significantly from 35.37% to 21.28%, within an angle of 10°. Based on an economic assessment, this coal dryer also proves that dried lignite coal has increased 4.9% economic value than bituminous coal.
Numerical Study of Savonius Wind Turbine Rotor with Elliptic Angle Shape Variation Antonius Hadi Sudono Putranto; Vivien Suphandani Djanali; Bambang Arip Dwiyantoro
JMES The International Journal of Mechanical Engineering and Sciences Vol 3, No 2 (2019)
Publisher : LPPM, Institut Teknologi Sepuluh Nopember, Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.12962/j25807471.v3i2.9367

Abstract

The Savonius wind turbine uses a half-cylinder blade which is often called a bucket assembled so that the cross-section forms an "S". This turbine is seen in the form of a half-cylinder consisting of a concave side and a convex side. This turbine is one type of Vertical Axis Wind Turbine (VAWT) that uses the difference in drag forces between the two buckets to be able to rotate the rotor. Therefore this rotor has the ability to self-start, which other wind turbines do not have, even so, the performance of the turbine. Savonius wind is still relatively low, so that it cannot be applied until now. Many studies have been carried out to improve performance, some of which include adding shielding, end plates, changing the shape of the blades, gap overlap, and others. The analysis in this numerical study included a comparison of the performance of conventional Savonius wind turbines and elliptic Savonius wind turbines with an assumed steady flow 2D flow and using turbulent viscous transitions k-kL-ω and k-ω SST with variations in flow velocity and angle of incidence of flow to the position of the rotor of the Savonius turbine. This results evaluated were the static torque coefficient with respect to the rotor position, the pressure distribution along the blade surface, and the wind flow characteristics near the rotor. The results of this study indicated that the modified wind turbine rotor had a higher static torque coefficient at low speeds. The two types of turbine rotors had relatively the same self-starting capability at high speeds.
Numerical Study of Heat Transfer Characteristics in High Pressure Steam Turbine During Stop Unit Process with Sliding Pressure Budi Santoso; Bambang Arip Dwiyantoro
The International Journal of Mechanical Engineering and Sciences Vol 6, No 2 (2022)
Publisher : LPPM, Institut Teknologi Sepuluh Nopember, Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.12962/j25807471.v6i2.12048

Abstract

During maintenance of the turbine and its auxiliary equipment, which requires a stop of the turbine oil system equipment and an open turbine casing, the first stage metal temperature requirement must be below 150°C. The normal stop unit method with natural cooling takes about 14 to 17 days. In order to speed up the cooling time to 5 days, a forced cooling turbine is needed using the stop unit method with sliding pressure. The heat transfer that occurs in the high-pressure turbine during the stop unit process with sliding pressure was investigated using the numerical method of CFD simulation. The 2D geometry design was made from high-pressure turbine cutouts images. Then meshing was made. The solver stage and the post-processing stage were set. The simulation was running in a steady state and followed by transients. The validation method was to compare the first stage metal temperature parameter between the actual process and the results of the CFD simulation at a load of 350 MW, then re-simulate it at 500 MW and 645 MW. The stop unit process with sliding pressure starting at 645MW resulted in the best final cooling compared to the stop unit at 500 MW and 350MW loads. By increasing the main steam flow, the resulting cooling increases. By increasing the value of the fluid flow velocity, the Reynolds number increases, so the convection heat coefficient also increases.
Numerical Study of Reducer Modification with Adjuster Opening Variations on Turbine Lube Oil Pipe Agus Aopik; Bambang Arip Dwiyantoro
JMES The International Journal of Mechanical Engineering and Sciences Vol 7, No 1 (2023)
Publisher : LPPM, Institut Teknologi Sepuluh Nopember, Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.12962/j25807471.v7i1.12065

Abstract

The success criteria of the power plant are represented by EAF (Equivalent Availability Factor) value. In 2021, one of the causes of the Forced Outage (FO) at Adipala Steam Power Plant was the failure of the main lube oil turbine pipe. The sudden contraction of the reducer resulted in the previous failure. Modifications were made to the reducer using a conical shape to reduce the number of welding processes and minimize the probability of failure. Therefore, a study on reducer modification needs to be carried out to study the impact of changing the shape of the reducer and changing the opening check valve on process parameters and flow in the main lube oil turbine pipe. The modification of the reducer was the main focus in this study. This research aims to analyze the pressure of turbine lube oil in the existing adjuster and the modified adjuster, using the Computational Fluid Dynamics technique with check valve adjuster variations (distance between the tip of the check valve and the inner wall of the reducer). The inlet boundary condition was defined by a pressure inlet of 285803.4 Pa. Outlet boundary condition was set by a mass flow of 65.72 kg/s. The curve surface was set as wall boundary conditions with a stationary wall, no-slip, and standard roughness model. The oil pressure in the modified adjuster increased compared to the oil pressure in the existing adjuster. The pressure on the oil flow was required to distribute oil to the turbine bearings. With the small increase in pressure after the modification, the turbine lube oil transfer improved. The pressure drop (ΔP) value that occurred in the conical-shaped modified adjuster was smaller than the pressure drop (ΔP) in the existing adjuster. This is because the resistance on the modified adjuster was less than the existing adjuster. The flow streamlines that formed backflow and vortex on the conical modified adjuster were less compared to the existing adjuster due to fewer obstacles in the conical modified adjuster.
Co-Authors Agus Aopik Alfian Bani Susiloputra Alvin Mizrawan Tarmizi Alvin Mizrawan Tarmizi Annis Khoiri Wibowo Antonius Hadi Sudono Putranto Aripin Gandi Marbun Aripin Gandi Marbun Budi Santoso Dendi Nugraha Edo Wirapraja Khoiruz Zadit Taqwa Reza Hidayatullah Rezky Fadil Arnaw Ryan Hidayat Sandy Pramirtha Shiu-Wu Chau Shiu-Wu Chau Siti Duratun Nasiqiati Rosady Unggul Dwi Setyadi Vivien Suphandani Djanali