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Pengambilan minyak melati (Jasminum sambac) dengan metode enfleurasi telah dilakukan dengan memvariasikan waktu enfleurasi dan jenis adsorben. Metode enfleurasi dapat mencegah kerusakan minyak atsiri yang diperoleh karena dilakukan pada suhu rendah. Tujuan penelitian untuk melihat jenis adsorben dan berat bunga yang tepat untuk mendapatkan minyak melati optimum. Penelitian dilakukan dengan memvariasikan jenis adsorben (mentega putih dan mentega kuning) dan waktu enfleurasi (6, 10, 12, 16, dan 20 hari). Parameter yang diamati adalah rendemen, komponen minyak, densitas, aroma dan warna minyak yang diperoleh. Hasil penelitian menunjukkan adsorben mentega putih lebih efektif dibandingkan mentega kuning dengan perolehan minyak atsiri tertinggi pada waktu enfleurasi 20 hari dan jumlah bunga 230 gram dengan rendemen 8,69%. Perolehan minyak terendah dengan rendemen 5,21% menggunakan adsorben mentega kuning pada waktu enfleurasi 10 hari dengan berat bunga 115 gram. Komponen-komponen dominan yang terdeteksi dalam minyak diantaranya adalah linalool (8,82%), benzyl acetat (4,58%), hexyl salicylate (4,90%), 1-Phenanthrenecarboxylic acid (5,99%), versalide (3,14%), dan 3-phenyl-propenal (3,29%). Minyak melati yang dihasilkan berwarna kuning muda jernih dengan densitas berkisar antara 0,8821-0,8845 g/mL pada penggunaan adsorben mentega putih dan 0,8175-0,8675 g/mL dengan adsorben mentega kuning. Hasil uji organoleptik menunjukkan rata-rata panelis menyukai aroma dan warna pada minyak melati pada perlakuan waktu enfleurasi 6, 10, dan 12 hari dengan tingkat kesukaan panelis 100% suka

Flow structure inside a chamber greatly determines the process performances. Therefore, the flow structure inside a chamber are often constructed in such a way as an effort to obtain equipment performances in accordance with the expectations. This study explored flow structure inside several chamber geometries and operating conditions. Three types of chamber, namely; GTC, DTC and TJC were set as the investigated chambers. The Computational Fluid Dynamics technique, supported by some experimental data from the literature, is used as an investigation method. The RANS based models, under Ansys-Fluent software were used in this numerical investigation. Simulation results revealed that the flow structures of GTC and DTC are predominantly created by spiral and vortex patterns. The vortex stabilizer diameter in the GTC affects the vortex pattern, velocity profile and pressure drop. The flow structure of DTC presents the most complex behavior. The flow structure inside TJC, in the case of unconfined outlet boundary, is characterized by the helical and wavy jet pattern. This structure is determined by the initial tangential intensity (IIT) and the inlet aspect ratio (RIA). The structures of vortex, helical, and wavy axial flow are properly constructed and visualized in this paper. There is no a turbulence model which is always superior to the other models, consistently. The standard k-ε model exhibits the realistic and robust performances among all of investigatied cases.

Miscanthus is one of the potential bioenergy crops in the world. This non-woody biomass can grow almost anywhere and does not require high cultivation costs. Its energy content is approximately 525 GJ/ha/year, the highest among other non-woody biomass. This research aims to study the potency of Miscanthus × giganteus as fuel in a suspended furnace. Some combustion characteristics of Miscanthus particles were determined experimentally and numerically. At a 40°C/min heating rate, the particle's initial and active decomposition temperatures are 197 and 352°C, respectively. The study also reveals that the combustion mode of the Miscanthus particles was affected by the furnace temperature. At furnace temperatures of 300–400°C, the combustion mode of the Miscanthus particles refers to the simultaneous combustion model. While, at temperatures 450–600°C, its combustion produces extensive flames and is called the sequential combustion model. The extensive flames are useful in cyclone furnaces to maintain combustion stability. Under cold modelling, the average drag time of the representative particles with an equivalent diameter of 1384 µm, in a typical furnace, is 26.82 s, much higher than its combustion time of 11.25 s. This indicates that the particles can be burned out in a suspended state. [ABSTRACT FROM AUTHOR]

Computational fluid dynamics (CFD) is a powerful tool to provide information on detailed turbulent flow in unit processes. For that reason, this study intends to reveal the flow structures in the horizontal pipe and biomass combustor. The simulation was aided by ANSYS Fluent employing standard k‐ ε model. The results show that a greater Reynolds number generates more turbulence. The pressure drop inside the pipe is also found steeper for small pipe diameters following Fanning's correlation. The fully developed flow for the laminar regime is found in locations where the ratio of entrance length to pipe diameter complies with Hagen–Poiseuille's rule. The sucking phenomenon in jet flow is also similar to the working principle of ejector. For the biomass combustor, the average combustion temperature is 356–696°C, and the maximum flame temperature is 1587–1697°C. Subsequently, air initially flows through the burner area and then moves to the outlet when enters the combustor chamber. Not so for particle flow, the particle experiences sedimentation in the burner area and then falls as it enters the combustor chamber. This study also convinces that secondary air supply can produce more circulating effects in the combustor. [ABSTRACT FROM AUTHOR]

The knowledge of fluid–particle flow behavior is necessary. Unfortunately, computational fluid dynamics (CFD) studies are mostly focused on developing numerical methods in detail. Instead, the CFD studies should also subtly shift to become a tool for digitalizing fluid science to guide the practical industrial aspects. Therefore, this simulation study intends to reveal the air and rice husk flow behaviors in a vertical suspension furnace, complete with presenting digital simulation data, aiming to alleviate the escape particle amount. According to this study, the escaped particle amount was suppressed under more sphere particle, smaller particle size, and feed inlet pipe that sunk into the burner. The properties change from rice husk to ash, along with temperature escalation (as in combustion phenomena), enlarging the escaped particle amount, so the cyclone should be installed to handle it. In addition, the results of digital turbulent data from CFD simulation have succeeded in intriguing and revealing the fluid–particle flow behavior in the vertical suspension furnace. The data show a close match to the real phenomena occurring inside this furnace which reflects the standard k–ε model can conclusively predict fluid–particle flow behavior without conflicting Newton's second law of particle motion. [ABSTRACT FROM AUTHOR]

Abundant availability and large silica content in rice husk black ash (RHBA) make the use of it very interesting to study. Many works only deal with lab‐scale rice husk ash extraction while the studies on bench‐scale RHBA extraction are still limited. This study, hence, presents the influence of pretreatment, extraction variables, and posttreatment on bench‐scale RHBA processing to bio‐silica. The pretreatment through acid leaching was carried out using HCl. The extraction was implemented under varying process variables such as alkaline‐to‐feed ratio (RA/F), extraction duration, and acid precipitation agent. According to this study, the highest extraction yield up to 98% was gained under RA/F 6 g/g and 1‐h extraction. The amorphous bio‐silica had an asymmetric siloxane bond and white appearance with a purity exceeding 95% and surface area up to 406.98 m2/g. Meanwhile, precipitation under HCl and H2SO4 had little impact on product purity and surface area. This study exhibits that acid leaching is executed to release mineral impurities but is still not sufficient to remove the remaining carbon content in bio‐silica. However, the contribution of refining process is able to do so. Moreover, the produced bio‐silica is suitable for adsorbent purposes which could adsorb up to 83.5% of 3‐monochloropropanediol compound. [ABSTRACT FROM AUTHOR]