Bambang Arip Dwiyantoro
Institut Teknologi Sepuluh Nopember

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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

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%.
Effect of Diffusers Installation in Inlet Primary Air Coal Pulve R. Panji Satrio Wening Galih; Bambang Arip Dwiyantoro
JMES: 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.v6i2.12045

Abstract

This paper investigates the effect of installing several diffuser models in the pulverizer ZGM123-GII inlet ducting on air flow characteristics and wear concentration. Results of the internal check found that an area of the wall and the surrounding components were wearing abnormally or faster than usual. This condition will affect the availability of the pulverizer. There are 6 variations model used in this study to solve this problem. The 2 variations in the number of blade, there are 2 and 3 blades, combined with 3 angle variations, namely 30o, 45o, and 50o. In this study, the viscous k-omega SST model was used to simulate airflow from the primary inlet to the area above the throat ring. The results show the contours of velocity of the air and the velocity vector on the pulverizer. Model with an angle of 45 degrees and the number of blade 3, is able to circulate air dominantly on the left side of the primary air inlet ducting, according to the reference study. From all variations, the model 45o angle with 3 blades and 50o angle with 3 blades are able to overcome the wear concentration problem.
Numerical Study of Heat Transfer Characteristics in High Pressure Steam Turbine During Stop Unit Process with Sliding Pressure Budi Santoso; Bambang Arip Dwiyantoro
JMES: 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 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 theturbine. 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-ωSST 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.