Study of Hydrodynamics and Overall Gas Hold Up Validation in Bubble Column by Computational Fluid Dynamics

The study of overall gas hold up has been carried out experimentally with the bed expansion. The superficial gas velocities used for the experiments are 6.369 m/s and 10.616 m/s. The experiment is carried out in a bubble column with inside diameters of 7 cm and a height of 100 cm. Gas from the gas cylinder is supplied through a distributor consisting of a perforated plate and glass beads. The perforated plate has a hole diameter of 1 mm and 0.5 mm. Computational Fluid Dynamic (CFD) using a Eulerian coupled with Population Balance model is developed to predict overall gas hold up and bubble size distribution. The effect of superficial gas velocity, perforated plate diameter, gas properties, and initial liquid level on gas hold up were studied. The use of population balance can significantly improve the overall gas hold-up results compared to constant bubble diameter. It is found that several operating conditions affect the whole gas hold up, namely initial liquid level, superficial gas velocity, and differences in gas properties. While the influence of the difference in perforated plate diameter to overall gas holds up, results are small compared to other operating conditions

The Effect of Solid Rate on Cyclones Pressure Drop and Erosion Rate at Coal Boiler Plant Using Computational Fluid Dynamics

Gas-solid separation systems with turbulent swirl flow that occur inside the cyclone will cause pressure drop and erosion on the cyclone wall. Both of these can cause a decrease in performance and increase maintenance costs for cyclones. CFD simulation is carried out on the actual cyclone dimensions used in the coal boiler industry. It was performed using the Reynolds Stress Model (RSM) for turbulent flow in the gas phase and Oka erosion model for its erosion model. The inlet velocity is fixed 6 m/s with variations in the solid rate ranged from 30 to 40 kg/s. This study will analyze the pressure drop and erosion rate on the cyclone walls in various solid rate variations. The simulation results show that the higher the solid rate with the same speed will reduce the pressure drop by 4% and at selected local area, increase the erosion rate on the cyclone wall by about 19

Sistem Informasi Layanan SMS Gateway Bagi Bidan Dalam Program Pemantauan Kesehatan Ibu Dan Anak (PWS KIA) Di Kabupaten Bantul Provinsi Daerah Istimewa YOGYAKARTA

Pemantauan wilayah setempat kesehatan ibu dan anak (PWS KIA) merupakan program pemerintah dalam monitoring perkembangan kesehatan ibu dan anak di suatu wilayah. Keberhasilan program PWS KIA tidak terlepas dari peran bidan dalam pengumpulan data dan luas cakupan wilayah sehingga pelaporan baru diperoleh pada periode tertentu sementara informasi yang dibutuhkan bersifat realtime layanan. Pemanfaatan teknologi telekomunikasi khususnya perangkat mobile merupakan teknologi yang banyak digunakan masyarakat dalam berkomunikasi . Pertukaran pesan melalui Sort Message Service (SMS) merupakan media komunikasi yang paling efektif dalam menyampaikan pesan. Perkembangan Teknologi SMS Gateway memungkinkan untuk mengolah data pesan SMS menjadi suatu informasi yang bermanfaat. Berdasarkan uraian  diatas, maka  adapun tujuan penelitian mengembangkan sistem layanan SMS gateway dalam program PWS KIA dengan metode waterfall dalam pengembangan  perangkat lunak. Pengembangan sistem menggunakan bahasa pemrograman PHP, DBMS MySQL dan Gammu SMS Gateway. Hasil penelitian diharapkan dapat memberikan kemudahan bagi bidan untuk melaporkan setiap layanan PWS KIA secara realtime dan diharapkan Dinas Kesehatan Bantul dapat memperoleh data terbaru  layanan PWS KIA  tanpa harus menunggu dalam periode tertentu

The Effect of Water Contents to Diesel Fuel-Water Emulsion Fuel Stability

The declining world oil and gas reserves along with increasing gas emissions from fossil fuel consumption has received serious attention as an urgent problem worldwide. The alternative solution to the problem uses emulsified fuel which is expected to provide better combustion efficiency and will contribute to emission reductions, such as NOx and particulate matter (PM). The one of most important factor in emulsion fuel is its stability. In this work, the effect of water contents to stability of diesel-water emulsion fuels has been investigated. The stability of emulsion fuel related to coalescence and sedimentation formation. The diesel fuel-water emulsification process was carried out in a standard stirred tank consisting of a cylinder tank (93 mm in diameter) and Rushton disk turbine (40 mm in diameter). Materials used consist of diesel oil (Pertamina DEX), demineralized water, surfactants (Lecithin, Triton X-100 and Tween 80). The surfactant used is a mixture of Lecithin - Triton X-100 (76.6%: 23.4%) and Lecithin - Tween 80 (45.5%: 54.5%) at 1% total volume of emulsion. The impeller set in constant speed at 1900 rpm. To reduce emulsification energy consumption, water is added gradually into the tank at 2 mL/min of flowrate. Water content varies at 5%, 10%, 20%, and 40% by total volume of emulsion. Physical properties of emulsion fuel such as viscosity and density at room temperature were investigated periodically. The characterization of emulsion fuel stability was measured by slope value of absorbance ratio at wavelength 450 nm and 850 nm. Sediment formation was periodically by visual observation as emulsion phase percentage. Emulsion droplet size was measured by Dynamic Light Scattering (DLS) method. Physical properties of emulsions such as density and viscosity tend to constant value in order of time. Emulsion fuel with 5% water content has the largest volume of emulsion phase in the rest of time, 83 % for L-T emulsion fuel and 95% for L-Tx. The lowest slope value shown by 5% emulsion fuel water content, -8.657×10-5 for 5% L-T emulsion fuel and -2,084 × 10-4 for 5% L-Tx emulsion fuel. Droplet size measurement of emulsion shown that different amount of added water caused the different droplet size of emulsion

Computational Fluid Dynamics Simulation of Clearance Effect in High Solid Loading Polydisperse Solid-Liquid Mixing

A high solid loading concentration of solid-liquid mixing was investigated to observe the effect of ratio C, Clearance, and T, diameter tank, with C/T 0.33; C/T 0.25 and C/T 0.17 on local volume of hydrodynamic and spatial distribution of polydisperse solid suspension using CFD, Computational Fluid Dynamics. The 45o pitch blade turbine, diameter 0.5T, with down pumping flow simulation was used to remove solid particle from bottom of the tank. The tank is also equipped with four baffle with the size of 0.1T.. A solid-liquid mixing consists of five fractions of glass beads with equal proportion (X1=X2=X3=X4=X5=0.2X) have 40% wt total solid concentration with liquid fraction is aqueous solution of NaCl. The effect of ratio C/T at impeller speed 612 rpm create a flow pattern in the tank different. Effect ratio C / T also indicated the distribution on solid had a good uniformity index when N≥ Njs, just suspended speed. The highest uniformity was obtained on C/T 0.17. it also made difference power consumption on each geometry with C/T 0.17, 0.25, and 0.33 respectively are 251.18, 238.13, and 270.65watt

Studi Analisa Ekonomi Pabrik CPO (Crude Palm Oil) dan PKO (Palm Kernel Oil) Dari Buah Kelapa Sawit

Kelapa sawit merupakan salah satu komoditi utama yang mempengaruhi pertumbuhan ekonomi Indonesia. Industri pengolahannya memberikan kontribusi yang penting dalam menghasilkan devisa dan lapangan pekerjaan. Hal tersebut dikarenakan minyak kelapa sawit  merupakan industri hulu yang sangat penting bagi berbagai industri lainnya, seperti: makanan, kosmetik, sabun dan cat. Bahkan akhir-akhir ini ada upaya penggunaan minyak kelapa sawit sebagai bahan baku pembuatan bahan bakar alternatif. Kondisi ini memacu perkembangan industri pengolahan kelapa sawit, baik kebutuhan dalam negeri maupun ekspor. Dan perkembangan industri sejalan dengan semakin meningkatnya luas areal perkebunan kelapa sawit. Kapasitas produksi kelapa sawit direncanakan sebesar 237.600 Ton/tahun. Perencanaan ini berdasarkan jumlah lahan yang dimiliki oleh pabrik. Dalam pemenuhan kapasitas tahunan, pabrik akan beroperasi kontinyu 24 jam per hari selama 330 hari Untuk memproduksi CPO sebesar 89.742 ton/tahun diperlukan bahan baku TBS 237.600 ton/tahun, CO2 199 ton/tahun dan propan 9 ton/tahun. Selain CPO, pabrik ini juga menghasilkan produk berupa Palm Kernel Oil (PKO) yang dihasilkan sebanyak 9.338 ton/tahun. Dari perhitungan analisa ekonomi, dengan harga jual CPO sebesar $562 per ton dan harga PKO sebesar$810 diperoleh Internal Rate Return (IRR) sebesar 45%. Dengan IRR tersebut mengindikasikan bahwa pabrik layak untuk didirikan dengan suku bunga 12% dan waktu pengembalian modal (pay out period) selama 2,6 tahun. Perhitungan analisa ekonomi didasarkan pada discounted cash flow. Modal untuk pendirian pabrik menggunakan rasio 60% modal sendiri dan 40% modal pinjaman. Modal total yang dibutuhkan untuk mendirikan pabrik adalah sebesar Rp. 211.001.470.206 dan laba bersih yaitu sebesar Rp. 112.838.149.952. Sedangkan Break Event Point (BEP) yang diperoleh adalah sebesar 36,53%

Petrophysical Study and Rock Type Determination of Siliciclastic Reservoir: Case Study Sand of Bekasap Formation, AF Field, Central Sumatra Basin, Indonesia

An integrated subsurface study has been performed for a large and mature field at the Bekasap Formation in Central Sumatra Basin. The Bekasap Formation sand represents an undeveloped reservoir because of its heterogeneity. There are five sand reservoirs (BK1, BK2, BK3, BK4, and BK5) from Bekasap Formation, which each zone or layer bounded by a flooding surface. Each sand reservoir has particular characterization based on petrophysical properties that represent geological process. The petrophysical properties consist of shale volume, porosity, and water saturation obtained by wireline log calculation. This study uses conventional core data to validate the log calculation to achieve an accurate interpretation. Bekasap reservoir is a sandstone reservoir deposited in an estuarine with tide-dominated. Formation evaluation was done to determine the interest zone by petrophysical properties. The result well-log calculation and reservoir cut-offs showed the thickest reservoir in the BK 3 with the best average values of petrophysical properties with an average shale volume 0.32; porosity of 0.245. Otherwise, in rock type determination, four lithofacies are divided in the reservoir based on flow units. The sample RT 1 and RT2 provided the best reservoir zones with HFU1 and HFU2. The RT 3 and RT 4 dominated in HFU3 and HFU4 had the lowest potential zones of reservoir. The final findings showed a good correlation between sedimentologic analysis and petrophysical properties in the rock type determination. As a result, the best reservoir quality development is controlled by the depositional environment (texture and structure) rather than the diagenetic process in this reservoir. It is proven by petrophysical properties in BK1, and BK2 is coastal barrier sand (tidal sand bar) has more clean sand rather than in BK3 and BK4 deposited in the offshore bar

Computational Fluid Dynamics Simulation of Clearance Effect in High Solid Loading Polydisperse Solid-Liquid Mixing

A high solid loading concentration of solid-liquid mixing was investigated to observe the effect of ratio C, Clearance, and T, diameter tank, with C/T 0.33; C/T 0.25 and C/T 0.17 on local volume of hydrodynamic and spatial distribution of polydisperse solid suspension using CFD, Computational Fluid Dynamics. The 45o pitch blade turbine, diameter 0.5T, with down pumping flow simulation was used to remove solid particle from bottom of the tank. The tank is also equipped with four baffle with the size of 0.1T.. A solid-liquid mixing consists of five fractions of glass beads with equal proportion (X1=X2=X3=X4=X5=0.2X) have 40% wt total solid concentration with liquid fraction is aqueous solution of NaCl. The effect of ratio C/T at impeller speed 612 rpm create a flow pattern in the tank different. Effect ratio C / T also indicated the distribution on solid had a good uniformity index when N≥ Njs, just suspended speed. The highest uniformity was obtained on C/T 0.17. it also made difference power consumption on each geometry with C/T 0.17, 0.25, and 0.33 respectively are 251.18, 238.13, and 270.65watt

Effect of Mixing Time to Homogeneity of Propellant Slurry

Propellant is a rocket fuel that can be solid or liquid. This research focused on composite solid propellant that was made from solid and liquid materials become a slurry. Homogeneity of the propellant slurry is important to investigate because it can affect specification and performance of the propellant. This research objective was to study effect of mixing time to homogeneity of propellant slurry that was processed by horizontal sigma blade mixer. Density data were used to assess the homogeneity and stated as degree of homogeneity. The result showed that the mixing time affect the density values and it was obtained the most homogeneous slurry was at total mixing time 135 minut

Aplikasi Packet Diffusion Model untuk Menganalisis Pengaruh Fenomena Micromixing terhadap Jalannya Reaksi Kimia Paralel di dalam Reaktor Tangki reraduk Kontinyu dengan Aliran Umpan Terpisah

The effect of turbulent  mixing on  the  course  of two fast parallel competitive  chemical reactions  (netralization  of sodium  biborate  snd  iodide-iodate  oxidation-reduction  reactions) carried  out  in  continuous  stiwed  tank  reaktors  have been  studied  theoretically,  using  PacketDiffusion  Model,  and  experimentally  to  validate  the  theoretical predictions.System studied  consists  of flat bottom  cylindrical  tank  0.2 m in  diameter.  The height of liquid  in  the  tank  is  also  0.2 m. The  tank  was equipped  with Fan Turbine  with diameter equal  to I/3  tank  diameter. Sulphuric  acid solution  (0.5  Il,Q was fed into  the  tank through  2 mm-diameter pipe,  and  the  aquous  solution containing 0.0909  M NaH2Boj,  0.0909  M H:Bo:,  0.0116667  M KI, and  0.0023333  M KIO3wasfed  into  the  tank  through  I0  mm-diameter  pipe.  The rate  of acid solution  was  varied  0,045,  0.068,  and 0.09  liter/minute,  while the  rate  of  the  other solution  was varied  I,  1.5,  and  2 liter/minute  (the  rate  variation  coruespond  to  the  mean residence  time variation of 6, 4, and 3 minutes). The  impeller  rotation  speedwas  varied;  9,12,  and  I5  rps.  The iodine  concenftation  in  the  tank  influent  was  analyzed  using  spectrophotometer.The  simulation  works  conclude  that  the  selectivity  of iodine  decrease  with  increasing impeller  rototion  speed for the  mean  residence  time of 3 and 4 minutes,  while for the  mean residence  time of  6 minutes,  the iodine  selectivity increase  with  increasing  impeller  rotation speed. Increasing  the  mean residence  time from 3 to  4 minutes will decrease  the  iodine selectivity, while  increasing  the  mean residence  time further to  6 minutes  will  increase  the selectivity.  The theoretical  prediction  using  Packet  Difusion  Model agree fairly well  with  the experimental data.  The  experimental studies  also  showed  that  the feed position  in  the  region  of high  turbulent  intensity  (impeller  region)  give  lower iodine  selectivity compaired  to  the selectivity  in  the  region  of lower  turbulent  intensity.  The  Packet  Dffision  Model  cannot simulate  the  effect  offeed  position  on the  iodine  selectivity.Keywords:  Packet  Diffusion Model, Micromixing, and  Continuous  Stirred  Tank  Reacto