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"The aim of this study is to evaluate the effects of absorbent flow rate on CO2 absorption through a super hydrophobic hollow fiber contactor. The absorbent used in this study was a physical absorbent, namely a polyethyleneglycol-300 (PEG-300) solution. Meanwhile, the feed gases used in the experiments were pure CO2 and a mixture of 30% CO2 and 70% CH4. Gas absorption using a physical absorbent provides various benefits; for example, it can produce sufficiently high selectivity towards CO2 and it is less corrosive than chemical solvents. Three super hydrophobic hollow fiber contactors, each 6 cm in diameter and 25 cm in lengthconsist of 1000, 3000 and 5000 fibers, respectively, were used in this study. The type ofsuper hydrophobic fiber membrane used was polypropylene-based, with an outer and inner diameter of about 525 and 235 µm, respectively. During the experiments, the absorbent was flowed through the lumen fibers, whilst the feed gas flowed through the shell side of the membrane contactors. The experimental results showed that the mass transfer coefficient, the flux, and the absorption efficiency increased, but the CO2 loading decreased, with increasing absorbent flow rate in the membrane contactor. Meanwhile, it was found that an increase in the number of fibers in the membrane contactor, in general, will increase the absorption efficiency and the CO2 loading, but will decrease the overall mass transfer coefficient and the flux."

"Telah dilakukan penelitian mengenai proses sintesis polyacrylic acid yang bertujuan untuk mengetahui pengaruh penambahan polimer pada peningkatan kapasitas penyerapan air. Sampel yang digunakan untuk mengetahui kapasitas penyerapan air yaitu produk absorben komersial berupa Disposable Baby Diapers. Proses sintesis polimer dilakukan dengan metode polimerisasi emulsi dengan teknik semi-kontinyu dengan komponen komposisi yaitu aquades, surfaktan anionik SDS, dan larutan PVA terhidrolisis sebagian medium viscosity. Kemudian untuk monomer acrylic acid dan inisiator APS dicampurkan secara kontinyu selama proses sintesis berlangsung pada temperatur ±70°C, kecepatan agitasi 300 rpm, dan waktu sintesis selama 4 jam dengan tiga variasi komposisi yaitu PAA, PAA+SDS, dan PAA+SDS+PVA. Kapasitas penyerapan air dihitung dengan mengikuti standar dari ASTM D570-98 dan diperoleh nilai kapasitas penyerapan air yang meningkat pada semua variasi komposisi dengan dilakukan pelapisan sebanyak 1 gram pada sampel diapers dan diperoleh peningkatan kapasitas penyerapan air pada variasi komposisi satu sebesar 229%, variasi kedua sebesar 206%, dan variasi ketiga sebesar 705%.

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Research has been conducted on the synthesis process of polyacrylic acid to determine the effect of adding polymer on the water absorption capacity. The sample used to determine water absorption capacity is a commercial absorbent product in Disposable Baby Diapers (DBD). The polymer synthesis process utilized the emulsion polymerization method with a semi-continuous technique. The composition included distilled water, SDS anionic surfactant, and partially hydrolyzed PVA solution with medium viscosity. Acrylic acid monomer and APS initiator were continuously mixed during the synthesis process at a temperature of approximately 70°C, an agitation speed of 300 rpm, and a synthesis time of 4 hours. Three composition variations were used, namely PAA, PAA+SDS, and PAA+SDS+PVA. The water absorption capacity was calculated following the ASTM D570-98 standard. The resultsshowed an increased water absorption capacity for all composition variations. Coating 1 gram of the sample diapers resulted in an increase of 229% for the first composition variation, 206% for the second variation, and 705% for the third variation."

"NOx dan SO2 merupakan komponen primer hasil pembakaran bahan bakar fosil. Dengan dihadapinya komitmen serta tantangan dalam pengendalian emisi NOx dan SO2, maka dikembangkannya berbagai teknologi dan metode dalam penurunan tingkat emisi gas NOx dan SO2, salah satu diantaranya yaitu penggunaan metode basah penyisihan gas, yaitu wet scrubbing. Penyisihan pada penelitian ini dilakukan dengan memanfaatkan membran kontaktor serat berongga berbahan dasar PVDF (polyvinylidene fluoride). Larutan absorben yang digunakan yaitu H2O2 dan HNO3, dimana H2O2 berfungsi untuk menyisihkan NOx dan SO2 dengan mengubah gas NOx menjadi gas yang lebih larut dalam air, sedangkan HNO3 digunakan sebagai autokatalis untuk mempercepat laju reaksi penyisihan. Variabel bebas pada penelitian ini yaitu laju alir gas umpan NOx dan SO2 dan konsentrasi H2O2 pada larutan absorben. Variasi laju alir gas umpan yang digunakan yaitu 100, 125, 150, 175, dan 200 mL/menit, sedangkan variasi konsentrasi yang digunakan yaitu 0,02; 0,04; 0,06; 0,08; dan 0,1% b/v H2O2. Penelitian menghasilkan penyisihan gas NOx dan SO2 maksimum berurutan sebesar 98,5% dan 100%, yang didapatkan dengan konsentrasi H2O2 sebesar 0,1% b/v, pada laju alir gas umpan sebesar 100 mL/menit, dengan modul membran sebanyak 50 buah.

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NOx and SO2 are the primary gas components from the combustion of fossil fuels. With the commitment and challenges faced in controlling NOx and SO2 emissions, various technologies and methods were developed to reduce NOx and SO2 gas emission levels, one of which is the use of the wet gas removal method. The allowance in this study was carried out by using a hollow fiber contactor membrane made from PVDF (polyvinylidene fluoride). The absorbent solutions used are H2O2 and HNO3, where H2O2 was used to absorb the NOx and SO2 gases by converting NOx gas into a gas that is more soluble in water, while HNO3 is used as an autocatalyst to accelerate the rate of removal reactions. The independent variables in this study were the feed gas flow rate of NOx and SO2 and the concentration of H2O2 in the absorbent solution. Variations in the feed gas flow rate used were 100, 125, 150, 175, and 200 mL/minute, while the concentration variations used were 0.02; 0.04; 0.06; 0.08; and 0.1% w/v H2O2. The research resulted in maximum NOx and SO2 gas removal respectively 98.5% and 100%, which was obtained with a H2O2 concentration of 0.1%wt, a feed gas flow rate of 100 mL/min, and 50 membrane modules."

"Kontaktor membran serat berongga dapat menutupi kerugian yang terjadi pada metode konvensional. Terdapat dua jenis konfigurasi aliran dari membran kontaktor serat berongga ini. Konfigurasi 1 ketika pelarut dialirkan ke bagian tube and gas di bagian shell, sedangkan konfigurasi 2 sebaliknya. Penelitian ini dilakukan untuk menganalisis efektivitas antara dua konfigurasi tersebut dengan menggunakan larutan Triethanolamine 10% berat sebagai pelarut dan membran PVC. Hasil penelitian ini menyatakan bahwa konfigurasi 1 menghasilkan kinerja yang lebih baik dalam menyerap CO2 dibandingkan dengan konfigurasi 2. Penggunaan Triethanolamine sebagai pelarut menunjukkan kinerja yang kurang optimal, ditunjukkan dengan persentase CO2 yang terserap sekitar 1.98%.

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The hollow fiber membrane contactor overcomes the disadvantages of the conventional method. There are two flow patterns: Case 1 operation where the liquid flows in tube and gas in shell. The case 2 operation where the liquid flows at shell side and gas at tube side. This study is conducted to analyze the effectiveness between both patterns using 10% weight of Triethanolamine as the solvent and PVC membrane. The result of this study: the case 1 provides more effective CO2 absorption performance rather than case 2. The use of triethanolamine shows suboptimal performance, because the maximum CO2 absorbed was 1.98%."

"Penyerapan gas CO2 memiliki peran yang vital dalam industri gas alam. Teknologi alternatif untuk proses penyerapan CO2 ialah kontaktor membran serat berongga. Teknologi kontaktor membran ini dapat mengatasi kelemahan yang dimiliki kolom konvensional. Namun dalam prakteknya kontaktor membran masih memiliki kekurangan seperti permasalahan pembasahan membran oleh pelarut. Oleh karena itu penelitian ini akan menguji pengaruh laju alir pelarut dan jumlah serat membran dalam kinerja penyerapan gas CO2 murni melalui kontaktor membran serat berongga dengan bahan material membran bersifat superhidrofobik. Pelarut yang digunakan dalam penelitian ini adalah larutan DEA 5% volum. Variabel bebas yang digunakan pada penelitian ini ialah laju pelarut dan jumlah serat membran. Laju pelarut yang digunakan antara 100-500 cm3/menit, sedangkan jumlah serat membran 2000, 4000 dan 6000. Setiap percobaan dilakukan pada laju gas CO2 sebesar 240 cm3/menit. Parameter kinerja perpindahan massa yang dihasilkan pada penelitian ini yaitu efisiensi penyerapan 56%, laju CO2 terabsorpsi 9x10-2 mmol/s, koefisien perpindahan massa 6x10-4 cm/s, fluks CO2 1,85x--5 mmol/cm2.s, serta acid loading 9,5x10-2.

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The absorption of CO2 gas has a vital role in the natural gas industry. A promising alternative technology that overcome the disadvantages of conventional gas absorption is hollow fiber membrane contactor. However, in practice, contactor membrane still has problem such as wetting membrane by the solvent. Therefore this study evaluates the effect of solvent flow rate and the number of fibers in pure CO2 gas absorption performance through superhydrofobic hollow fiber membrane contactor using DEA 5%-volume as solvent. The abosrbent that we used in this research is diethanolamine (DEA) with the concentration 5 %-v. Independent variables in this research are solvent flow rate and the number of fibers. Solvent flow rate that we used between 100-500 cm3/minute, and for the amount of fibers are 2000, 4000 and 6000. Each of the experiments that conducted at the CO2 flow rate 240 cm3/minute. Results show that CO2 removal efficiency is 56%, while the rate of CO2 absorption is 9x10-2 mmol/s with overall mass transfer coefficient 6x10-4 cm/s, flux of CO2 absorption is 1.85x10-5 mmol/cm2.s and the acid loading is 9.5x10-2."

"Dalam studi ini, efektivitas penyerapan CO2 menggunakan kontaktor membran serat berongga dievaluasi berdasarkan variasi laju alir gas, variasi laju alir pelarut, dan alokasi cairan. Pada studi ini digunakan kontaktor membrane yang terdiri dari 50 serat PVC dan pelarut Triethanolamine. Laju alir gas yang digunakan adalah 0.1, 0.15 dan 0.2 L/min, sedangkan laju pelarut yang digunakan adalah 200, 250, 300, 350, dan 400 mL/min. Kemampuan penyerapan paling baik adalah ketika laju alir pelarut sebesar 400 mL/min, laju alir gas sebesar 0.2 L/min dan mengalirkan pelarut di dalam fiber.

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In this study, the effectiveness of CO2 absorption through hollow fiber membrane contactor is evaluated based on the gas flow rate variation, solvent flow rate variation, and fluid allocations. The present stud involves a membrane contactor with 50 PVC fibers and Triethanolamine as solvent. Gas flow rate used was 0.1, 0.15 L and 0.2 L / min, while the rate of solvent used is 200, 250, 300, 350, and 400 mL / min. The absorption is at its best when the solvent flow rate is 400 mL/min, when gas flow rate is 0.2 L/min and by flowing the solvent inside the fiber."

"Desired higher ship speeds can be achieved using many performance enhancement techniques. One of the techniques is drag reduction of ships’ hulls by imbuing their surfaces with hydrophobic properties This paper presents an alternative method of fabricating micro-riblets using laminate transfer molding to modify painting morphology for micro-riblets’ replication on ships’ hulls. A performance test of these micro-riblets is also performed. The results show that micro-riblets can be replicated from the pattern to the ships’ hulls. The geometries of micro-riblets are verified, which shows good agreement with the pattern. The performance of the fabricated micro-riblets was verified to decrease drag on the ship. As a result, ships’ speeds increased under similar propulsion power. The significant effect of micro-riblets is obtained with these higher speeds."

"Kontaktor membran serat berongga digunakan untuk mengabsorpsi gas CO2 murni. Bahan membran yang digunakan adalah polipropilen dan pelarut yang digunakan merupakan pelarut campuran senyawa amina (MEA/DEA) dan dibandingkan pelarut tunggal DEA. Penelitian ini menganalisis efektivitas perpindahan massa dengan menghitung nilai koefisien perpindahan massa (kL), fluks, dan korelasi perpindahan massa pada variasi laju alir pelarut 200,250,300,350,400 ml/menit dan jumlah serat 20,30,40. Hasil dari penelitian ini menunjukkan bahwa pelarut campuran MEA/DEA lebih efektif menyerap gas CO2 dibandingkan pelarut tunggal DEA pada laju alir 400 ml/menit dan jumlah serat 40 dengan nilai kL, fluks dan sebesar 0.00244 cm/s dengan persentasi CO2 yang terabsorpsi sebesar 93%.

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Hollow fiber membrane contactor was used for the absorption of pure carbon dioxide. The membranes applied were made of PVC and the absorbents included aqueous solution of mixed amine (MEA/DEA) that would be compared with single amine absorbent. This research detemined the mass transfer efficiency with determining mass tranfer coefficient, flux and mass transfer correlation under different absorbent flow rate 200,250,300,350,400 cc/minutes and number of fiber 20,30,40. The results showed that the mixed amine absorbent was more effective in doing absorption than the single amine under the flow rate absorbent 400 cc/minutes and number of fiber 40 with the value kL 0.00244 cm/s with percentage of CO2 absorped 93%."

"Nitrogen oksida NOx merupakan salah satu gas yang sangat berbahaya karena sifatnya yang beracun. Salah satu kandungannya, yaitu Dinitrogen Monoksida merupakan gas rumah kaca yang dengan potensi pemanasan global yang sangat besar. Untuk mengatasinya, telah muncul teknologi absorpsi menggunakan kontaktor membran. Kontaktor membran juga mempunyai keunggulan seperti rasio luas kontak dan volum peralatan yang tinggi. Proses absorpsi berlangsung dengan cara melarutkannya dalam absorben yang merupakan campuran oksidator, H2O2 dan HNO3. Variabel bebas yang diuji adalah laju alir absorben antara 100 ndash; 500 cm3/menit serta jumlah serat membrane 2000, 4000, dan 6000. Pada penelitian ini diketahui bahwa nilai koefisien perpindahan massa, fluks, jumlah N2O terserap, efisiensi penyerapan, dan penurunan tekanan semakin meningkat dengan meningkatnya laju alir pelarut. Sebaliknya, jumlah N2O loading akan semakin kecil. Selain itu, nilai koefisien dan fluks perpindahan massa menurun dengan bertambahnya jumlah serat membran. Sedangkan, jumlah N2O terserap, efisiensi penyerapan dan N2O loading malah akan meningkat.

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Nitrogen oxide NOx is a dangerous gas due to its toxic nature. One of it, namely Dinitrogen Monoxide is a greenhouse gas with high global warming potential. Absorption using membrane contactros is develop to overcome these problems. Another advantages is the high ratio of contact area and equipment volume. The absorption process occurs by dissolving it in the absorbent which is a mixture of oxidizer, H2O2 and HNO3. The independent variables tested were absorbent flow rate between 100 500 cm3 min and number of membrane fibers 2000, 4000, and 6000.

In this research, is obtained that the mass transfer coefficient, flux, N2O absorb, absorption efficiency, and pressure decrease is increasing as solvent flow rate increasing. Conversely, N2O loading is decreasing. In addition, coefficient and mass transfer flux value is decreasing as the increasing number of membrane fibers. Meanwhile, the N2O absorb, absorption efficiency and N2O loading is increasing."