Application of Benzotriazoleas Corrosion Inhibitor Ofapi 5lx65 in Sodium Chloride Solution

APPLICATION OF BENZOTRIAZOLEAS CORROSION INHIBITOR OFAPI 5LX65 IN SODIUM CHLORIDE SOLUTION. The inhibition mechanismofAPI 5LX65 carbon steel corrosion by benzotriazole (BTAH) in 0.5% NaCl solution saturated with CO2 at temperatures of 25, 45, 65 and 85 oC was investigated using electrochemical impedance spectroscopy (EIS). The measurements were done on the steel specimens after they were immersed into the test solutions containing BTAH for 30 hours. The polarization resistance, Rp, of each specimen was then determined with respect to electrical equivalent circuit proposed by Randall for a metal which is actively corroding in its environment. The data were then used to calculate the inhibition efficiency and surface coverage of carbon steel by BTAH. It was found that the BTAH concentration and temperatures of the test solutions affected significantly the inhibition efficiency. The presence of carbonic acid decreases the inhibition efficiency, however by using 8.40 mmol/LBTAH the inhibition efficiency had reached more than 90% at all temperatures. The increase of temperature has reduced the surface coverage and has lead to decrease the inhibition efficiency. The re-increase of inhibition efficiency at 85oC was related to the decrease in FeCO3 and CO2 solubility. Moreover, it was revealed that the adsorption of BTAH on the steel surface obeyed the Temkin's adsorption isotherm

APPLICATION OF BENZOTRIAZOLEAS CORROSION INHIBITOR OFAPI 5LX65 IN SODIUM CHLORIDE SOLUTION

APPLICATION OF BENZOTRIAZOLEAS CORROSION INHIBITOR OFAPI 5LX65 IN SODIUM CHLORIDE SOLUTION. The inhibition mechanismofAPI 5LX65 carbon steel corrosion by benzotriazole (BTAH) in 0.5% NaCl solution saturated with CO2 at temperatures of 25, 45, 65 and 85 oC was investigated using electrochemical impedance spectroscopy (EIS). The measurements were done on the steel specimens after they were immersed into the test solutions containing BTAH for 30 hours. The polarization resistance, Rp, of each specimen was then determined with respect to electrical equivalent circuit proposed by Randall for a metal which is actively corroding in its environment. The data were then used to calculate the inhibition efficiency and surface coverage of carbon steel by BTAH. It was found that the BTAH concentration and temperatures of the test solutions affected significantly the inhibition efficiency. The presence of carbonic acid decreases the inhibition efficiency, however by using 8.40 mmol/LBTAH the inhibition efficiency had reached more than 90% at all temperatures. The increase of temperature has reduced the surface coverage and has lead to decrease the inhibition efficiency. The re-increase of inhibition efficiency at 85oC was related to the decrease in FeCO3 and CO2 solubility. Moreover, it was revealed that the adsorption of BTAH on the steel surface obeyed the Temkin’s adsorption isotherm

Investigation of Vortex Clouds and Droplet Sizes in Heated Water Spray Patterns Generated by Axisymmetric Full Cone Nozzles

The hot water sprays are an important part of many industrial processes, where the detailed knowledge of physical phenomena involved in jet transportation, interaction, secondary breakup, evaporation, and coalescence of droplets is important to reach more efficient processes. The objective of the work was to study the water spray jet breakup dynamics, vortex cloud formation, and droplet size distribution under varying temperature and load pressure. Using a high speed camera, the spray patterns generated by axisymmetric full cone nozzles were visualized as a function water temperature and load pressure. The image analysis confirmed that the spray cone angle and width do not vary significantly with increasing Reynolds and Weber numbers at early injection phases leading to increased macroscopic spray propagation. The formation and decay of semitorus like vortex clouds were also noticed in spray structures generated at near water boiling point temperature. For the nozzle with smallest orifice diameter (1.19 mm), these vortex clouds were very clear at 90°C heating temperature and 1 bar water load pressure. In addition, the sauter mean diameter (SMD) of the spray droplets was also measured by using Phase Doppler Anemometry (PDA) at different locations downstream of the nozzle exit. It was noticed that SMD varies slightly w.r.t. position when measured at room temperature whereas at higher temperature values, it became almost constant at distance of 55 mm downstream of the nozzle exit

Characterization of Modified Tapioca Starch Solutions and Their Sprays for High Temperature Coating Applications

The objective of the research was to understand and improve the unusual physical and atomization properties of the complexes/adhesives derived from the tapioca starch by addition of borate and urea. The characterization of physical properties of the synthesized adhesives was carried out by determining the effect of temperature, shear rate, and mass concentration of thickener/stabilizer on the complex viscosity, density, and surface tension. In later stage, phenomenological analyses of spray jet breakup of heated complexes were performed in still air. Using a high speed digital camera, the jet breakup dynamics were visualized as a function of the system input parameters. The further analysis of the grabbed images confirmed the strong influence of the input processing parameters on full cone spray patternation. It was also predicted that the heated starch adhesive solutions generate a dispersed spray pattern by utilizing the partial evaporation of the spraying medium. Below 40°C of heating temperature, the radial spray cone width and angle did not vary significantly with increasing Reynolds and Weber numbers at early injection phases leading to increased macroscopic spray propagation. The discharge coefficient, mean flow rate, and mean flow velocity were significantly influenced by the load pressure but less affected by the temperature

Pemanfaatan Limbah Bottom Ash Sebagai Adsorben Limbah Zat Warna Industri Tekstil

Limbah bottom ash dari industri tekstil dengan kadar karbon yang masih tinggi berpotensi untuk dijadikan karbon aktif. Pembuatan karbon aktif diawali dengan proses pemisahan karbon dari residu bottom ash menggunakan teknik floating. Karbon yang dihasilkan kemudian diaktivasi menggunakan uap pada suhu 1000 selama 1 jam. Karbon aktif kemudian digunakan untuk mengadsorbsi zat warna reactive black 5 dan acid red 4. Untuk melihat kemungkinan penerapan proses adsorbsi pada efluen limbah tekstil, dilakukan uji coba adsorbsi dengan proses kontinu pada reaktor vertikal. Karbon aktif yang diperoleh pada percobaan ini mempunyai luas permukaan spesifik 548 m2/g dan nilai kalori 6370 kal/g. Kapasitas adsorbsi, Kf pada zat warna reactive black 5 dan acid red 4 berturut-turut 56 dan 47 mg/g dan hasil ini lebih baik dibandingkan karbon aktif komersial. Analisa struktur mikro menggunakan Scanning Electron Microscope (SEM) menunjukkan karbon aktif bottom ash mempunyai struktur makro pori yang banyak pada permukaannya. Uji coba terhadap efluen air limbah indigo berhasil menurunkan warna dan COD sebanyak 34% dan 53%. Sedangkan percobaan terhadap efluen limbah zat warna reaktif/disperse berhasil menurunkan warna dan COD sebanyak 89% dan 61%

Karakterisasi Varistor Zno-bi203-cuo

KARAKTERISASI VARISTOR ZnO-Bi203-CuO. Untuk mengetahui peran CuO dalam pembentukan varistor, pembuatan dan karakterisasi varistor ZnO-Bi2O3-CuO telah dilakukan. Dalam studi ini dilakukan penyinteran pelet ZnO-0,8% mol Bi203 yang ditambahi 0,5; 1 dan 2 % mol CuO pada suhu 1100°C selama 1 jam. Pelet sinter dianalisis memakai metode metalografi dan difraksi sinar-x. Karakteristik listrik dan pelet tersebut juga dievaluasi. Penambahan CuO menaikkan tegangan patah dan memperbesar arus bocor varistor ZnO-Bi203, tetapi tidak meningkatkan faktor kenon-linearannya. Dengan konsentrasi CuO 0,5-2 % mol, harga faktor kenon-linearan yang didapat masih lebih kecil dari pada harga faktor kenon-linearan untuk varistor ZnO Bi203 dan masih lebih kecil dari pada faktor kenon-linearan untuk kebutuhan pasar (lebih besar 20), karena penambahan CuO tidak dapat membentuk jebakan elektron dalam. Hasil analisis metalografi dan difraksi sinar-x memperlihatkan bahwa pada struktur mikro varistor ZnO-Bi203-CuO, lapisan batas butir dibentuk oleh ZnO.24Bi2O3 dan butirnya dibentuk oleh larutan padat ZnO-Cu

Deposisi Film Tipis Ceria Didadah Nd Menggunakan Teknik Pulsed-laser Ablation Deposition (Plad)

DEPOSISI FILM TIPIS CERIA DIDADAH Nd MENGGUNAKAN TEKNIK PULSED-LASER ABLATION DEPOSITION (PLAD). Film tipis ceria didadah Nd (Nd-doped ceria/NDC) telah berhasil dideposisikan di atas substrat Si(100) pada ~temperatur 400°C menggunakan teknik pulsed-laser ablation depostion (PI‑AD) dalam kondisi vakum dan tekanan 02 antara 15 - 29 mTorr. Analisis difraksi sinar-x, scanning electron microscopy (SEM), dan energy dispersive x-ray (EDX) digunakan untuk mengamati struktur, ketebalan dan komposisi kimia film. Hasil studi ini menunjukkan bahwa tekanan 02 selama proses deposisi menentukan kristalisasi, ketebalan film dan komposisi atom dalam film. Film tipis NDC dengan struktur kompak dan komposisi beragam yang diperoleh menunjukan bahwa teknik PLAD berpotensi untuk menghasilkan film tipis elektrolit yang penting bagi solid electrolyte fuel cell (SOFC)