Hasil Pencarian  ::  Simpan CSV :: Kembali

"The research aims to scale up a small-scale stirred batch reactor to a large-scale stirred batch reactor in order to degum crude palm oil for use as a raw material in biodiesel production. The scale-up is based on the similarity of fluid Reynolds numbers in the two differently sized reactors. To achieve this aim, computational fluid dynamic modeling and simulations of the two reactors were performed. A small-scale palm oil degumming process was carried out in a 250 cc autoclave reactor using a magnetic stirrer at 500 rpm. The simulation results of this small reactor yielded a fluid Reynolds number in the range of 5 to 3,482. The large-scale reactor proposed in this research is 1.25 m3 in volume and is equipped with two impellers: a pitched blade impeller and a Rushton turbine impeller. The pitched blade impeller is placed over the Rushton turbine impeller. They are rotated at 100 rpm. Under this setting and operation, the resulting fluid Reynolds number was in the range of 486 to 202,000. This result indicates that the large-scale reactor was able to reproduce the reaction performance obtained in the small-scale reactor."

"The research aims to scale up a small-scale stirred batch reactor to a large-scale stirred batch reactor in order to degum crude palm oil for use as a raw material in biodiesel production. The scale-up is based on the similarity of fluid Reynolds numbers in the two differently sized reactors. To achieve this aim, computational fluid dynamic modeling and simulations of the two reactors were performed. A small-scale palm oil degumming process was carried out in a 250 cc autoclave reactor using a magnetic stirrer at 500 rpm. The simulation results of this small reactor yielded a fluid Reynolds number in the range of 5 to 3,482. The large-scale reactor proposed in this research is 1.25 m3 in volume and is equipped with two impellers: a pitched blade impeller and a Rushton turbine impeller. The pitched blade impeller is placed over the Rushton turbine impeller. They are rotated at 100 rpm. Under this setting and operation, the resulting fluid Reynolds number was in the range of 486 to 202,000. This result indicates that the large-scale reactor was able to reproduce the reaction performance obtained in the small-scale reactor."

"ABSTRAKPenelitian ini bertujuan menerapkan metode computational fluid dynamics dalam scale-up reaktor batch berpengaduk dengan studi kasus proses penghilangan getah minyak sawit mentah. Dalam scale-up tersebut, kesebangunan geometri reaktor tidak bisa dipenuhi. Koefisien perpindahan massa volumetrik kca dijadikan parameter kesamaan. Koefisien perpindahan massa yang diperoleh dari pengukuran laboratorium dikorelasikan dalam bentuk bilangan Sherwood sebagai fungsi bilangan Reynolds butir dan bilangan Schmidt dengan bentuk persamaan Shd = 0,02576 Red0,673Sc0.431. Luas bidang antarfasa diturunkan dari hasil simulasi menggunakan model mixture, setelah divalidasi dengan persamaan empiris. Sebagai acuan, digunakan kondisi operasi skala laboratorium 500 rpm dan 80 C dengan nilai kca sebesar 5,551x10-6 s-1. Simulasi reaktor skala besar dilakukan dengan variasi jenis impeller radial dan aksial , serta kecepatan putar 40, 75, 93, 141, dan 500 rpm . Dengan variasi tersebut, tidak diperoleh kesamaan nilai kca. Dari ekstrapolasi tren linear kca vs rpm, diperkirakan kriteria kesamaan diperoleh pada kecepatan 16,07 rpm. Namun, simulasi pada kecepatan tersebut tidak memberikan nilai yang diperkirakan. Penyebabnya gravitasi menjadi lebih dominan terhadap medan aliran sehingga dispersi tidak merata dan nilai kca terlalu kecil. Diperlukan studi lebih lanjut mengenai parameter geometri reaktor yang menghasilkan dispersi merata, sehingga dicapai kriteria kesamaan dalam scale-up reaktor.

---

ABSTRACTThis research aims to implement computational fluid dynamics for scale up of stirred batch reactor with case study of CPO degumming process. Reactor geometric similarity cannot be maintained while scale up. Volumetric mass transfer coefficient kca becomes similarity criteria. Mass transfer coefficient from laboratory data is correlated in Sherwood number as the function of drop Reynolds number and Schmidt number with the form Shd 0.02576 Red0,673Sc0.431. Interfacial area is derived from simulation using mixture model, by validating to empirical correlation. Laboratory scale reactor operating condition of 500 rpm, 80 C with kca of 5.551x10 6 s 1 is set as reference. Simulation of large scale reactor is run by varying the impeller type radial and axial and speed 40, 75, 93, 141, and 500 rpm . However, by those variations, kca similarity cannot be achieved. By extrapolating the linear trend between kca vs rpm, similarity is expected at 16.07 rpm. However, simulation doesn rsquo t confirm that. This is due to gravitational effect become more dominant and the equal dispersion is not obtained so that the kca is too low. It needs further investigation of the reactor geometries that will produce equal dispersion, so that similarity criteria of scale up can be achieved. "

"The combination ofbaffled air flotation and a membrane system for the treatment of palm oil milleffluent (POME) was studied. The POME was obtained from a palm oil factory inPTPN I Tanjong Seumantoh, Aceh, Indonesia. Operation variables and conditions,such as the hydraulic retention time and air flow rates, were varied to findthe optimum process. The air flotation process is able to reduce theconcentration of suspended solids and fats/ oils contained in the wastewater,which increases the performance of the membrane by reducing clogging. Theresults showed that this method was promising for POME treatment. The optimumorganic removal efficiency of the air flotation pretreatment was obtained atHRT = 5 days and at an air flow rate of 11 L/min. The effluent was subsequentlypassed through an anaerobic membrane system to achieve the highest removalefficiency treatment. The removal efficiency of chemical oxygen demand (COD),total suspended solids (TSS), turbidity, mixed liquor suspended solids (MLSS),mixed liquor volatile suspended solids (MLVSS), and fats/oils after passingthrough the membrane system were 97%, 93.9%, 99.8%, 94.5%, 96.2%, and 99.9%,respectively. The results also showed that the pH could be neutralized to 6.18,while a dissolved oxygen (DO) level of 1.60 mg/L could be achieved. A highquality of effluent was obtained, which met the standards for POME effluent."

"Oil palm empty fruit bunch (OPEFB) is one of the waste products of oil palm plantations and has not been optimally used in Riau Province, Sumatera, Indonesia. OPEFB is reduced by incineration, which causes pollution problems. However, the combustion of OPEFB generates ash, which is rich in potassium. Moreover, OPEFB fiber has good strength, low cost, low density, and biodegradability, and it can be used as composite reinforcement. However, the natural fibers in composites have poor compatibility with the matrix and relatively high moisture absorption. Hydrolysis of OPEFB ash creates a base solution that can be utilized in an alkaline treatment process to increase the mechanical properties of natural composites.The aim of this study was to investigate the effect of various extracts of OPEFB ash on the tensile strength, flexural strength, and water absorption of an OPEFB fiber-polypropylene composite. The experimental design used was the Response Surface Method-Central Composite Design (RSM-CCD). The results showed that the tensile strength increased with an increase of fiber length and concentration of the OPEFB ash extract solution, but tensile strength decreased with a longer soaking time. Flexural strength increased with an increase in fiber length but decreased with an increase in the concentration of the OPEFB ash extract solution and longer soaking time. Water absorption increased with lower and higher concentrations of OPEFB ash extract solution and fiber length and with shorter and longer soaking times. The highest tensile strength (20.100 MPa) was achieved at 5%wt alkaline concentration, 36 h soaking time, and 3 cm fiber length. The highest flexural strength (30.216 MPa) was achieved at 5%wt alkaline concentration, 12 h soaking time, and 3 cm fiber length. The lowest water absorption (0.324%) was achieved at 10%wt alkaline concentration, 24 h soaking time, and 2 cm fiber length."

"This study was aimed todetermine the reaction stoichiometry between Cu(II) and di-2-ethylhexylphosphoricacid (D2EHPA) in Waste Palm CookingOil (WPCO). The stoichiometry was computed based onthe followingexperimentalmethods, namely slope analysis, loading test and Job?smethod. Slope analysis was used to measure the variation of the distribution coefficient"

"This paper describes thecase study of Semanggi intersection in Jakarta, a dynamic model of emissionreduction in the land transportation sector. The urban transportation system isa complex system with multiple variables, feedback loops, and is influenced bysocial, economic and environmental factors. The proposed model consists of twosubmodels: Vehicle Fleet and Emission Calculation. The model runs inPowersim Studio software using data from the Indonesia Japan EconomicPartnership Agreement, and the TrafficManagement Centre of the Indonesian National Police. The test was conducted by developing two scenarios:Business As Usual and Intention. The estimated results to beobtained using the first scenario in 2021 should be 1,113,398 units, while thesecond scenario is estimated to produce 850,733 units. We hypothesize that theIntentional Approach will have a more significant impact than the TechnicalApproach, which requires more investment. The Intentional Approach is designed to improve the intention ofprivate car users to switch to public transportation. The Technical Approach to the emission measurement of everyvehicle in a certain area is the data of vehicle emission which are usuallytaken to determine the current condition. This research will no doubthave a positive impact on emission reduction in Jakarta."

"As a result ofwaterflooding, inorganic salt precipitation occurs in the different parts of anoil production system, thereby leading to damage of production equipment.Different parameters affect the kinetics of salt precipitation. Scaleinhibitors are widely used to prevent inorganic salt formation. In this study,the effect of reservoir pressure, temperature, and mixing ratio of injection toformation water on calcium sulfate and barium sulfate precipitation wasinvestigated. For this purpose, two different formation waters and oneinjection water were used. In addition, the effect of temperature and mixingratio on inhibition performance was studied. Four different existing industrialscale inhibitors and one new scale inhibitor were used. The performance of thescale inhibitors was determined under static and dynamic conditions. Results ofthe study showed that calcium sulfate precipitation increased with an increasein temperature and a decrease in pressure. Barium sulfate precipitation wasfound to increase with a decrease in the temperature. The effect of pressure onbarium sulfate formation was negligible. The developed scale inhibitor showedthe highest performance for the prevention of calcium sulfate and bariumsulfate formation. A change in temperature from 60°C to 120°C reduced theinhibitor performance by 3%. In the cases of calcium sulfate and bariumsulfate, the minimum performance of the scale inhibitor was observed when themixing ratios of injection to formation waters were 60:40 and 50:50,respectively."

"The purpose of this paper was to investigate the performance of ceramic filters made from a mixture of natural clay, rice bran, and iron powder in removing cadmium from pulp industry effluent. Some parameters were examined such as acidity, total dissolved solid (TDS), total suspended solid (TSS), electrical conductivity (EC), and cadmium concentration. Results showed that the composition percentage of the ceramic filter, which in this case amounted to 87.5% natural clay, 10% rice bran, and 2.5% iron powder, may decrease cadmium concentration in pulp industry effluent by up to 99.0%. Furthermore, the permeate flux decreased after 30 minutes of filtration time, and subsequently became constant at one hour of contact time. In addition, Scanning Electron Microscope (SEM) micrographs of the ceramic filter surfaces indicate that ceramic filters have a random pore structure and can be categorized as microfiltration filters."

"in this paper, a 4.2GHz collinear antena is designed to be used for computer management of vehicles/communication utility that can be integrated into combat systems, that is air defense systems (ADS) and combat field management systems (CMS)."