No abstract

Nuclear based technology called gamma scanning technique found its application for troubleshooting and diagnosing industrial process performance. The success of application of the gamma scanning technique is attributed to its unique ability in providing information which is cannot be obtained by any other techniques. One of the most prominent advantages of the gamma scanning technique was demonstrated by implementing this technology for scanning caustic/water wash tower DA 202 which was running in normal condition of operation. The DA 202 tower is trayed column having diameter of 4.2 m and height of 40 m. The scanning work has been performed using 70 mCi 60 Co isotope as gamma emitter and scintillation detector as radiation counter to investigate condition of ten trays, starting from tray # 13 at elevation of 35050 mm to tray # 4 at elevation of 26950 mm above ground level. Scan data show that all trays were in their position. Tray # 4 to tray #10 were functioned properly and carried approximately the same amount of liquid. Light flooding on tray # 11 and heavy flooding on tray # 12 were identified. Partial flooding was identified on tray # 13. Further examination at the time of shutdown it was found that the liquid flooding on tray # 12 was caused by presence of a bucket covered with solidified mud.

Multiphase flow modeling presents great challenges due to its extreme importance in various industrial and environmental applications. In the present study, prediction of separation length of multiphase flow is examined experimentally by injection of two kinds of iodine-based radiotracer solutions into a hydrocarbon transport pipeline (HCT) having an inner diameter of 24 in (60,96 m). The main components of fluids in the pipeline are water 95%, crude oil 3% and gas 2%. A radiotracing experiment was carried out at the segment of pipe which is located far from branch points with assumptions that stratified flows in such segment were achieved. Two radiation detectors located at 80 and 100 m from injection point were used to generate residence time distribution (RTD) curve resulting from injection of radiotracer solutions. Multiphase computational fluid dynamics (CFD) simulations using Eulerian-Eulerian control volume and commercial CFD package Fluent 6.2 were employed to simulate separation length of multiphase flow. The results of study shows that the flow velocity of water is higher than the flow rate of crude oil in water-dominated system despite the higher density of water than the density of the crude oil. The separation length in multiphase flow predicted by Fluent mixture model is approximately 20 m, measured from injection point. This result confirms that the placement of the first radiation detector at the distance 80 m from the injection point was correct.

Industrial waste-based geopolymer cement is a greener alternative to Ordinary Portland Cement (OPC) for radiation shielding with comparable mechanical properties without the production of CO 2 during synthesis. In this paper, the linear attenuation coefficient of slag and fly ash-based geopolymers, unmodified by aggregates, is measured and used to calculate the mass attenuation coefficients, half-value layer (HVL), and tenth-value layer (TVL) of the geopolymers. Narrow Beam Gamma Spectrometry with gamma energy of 0.662 MeV, 1.173 MeV, and 1.332 MeV was used to irradiate a series of slag and fly ash-based geopolymer paste of cylindrical shape with a diameter of 7.5 cm and height of 9.5 cm. Slag geopolymer has linear attenuation coefficient of 0.1642/cm, 0.1237/cm, 0.1150/cm, mass attenuation coefficient of 0.0782 cm 2 /g, 0.0589 cm 2 /g, 0.0548 cm 2 /g, the HVL of 4.222 cm, 5.609 cm, 6.056 cm, and TVL of 14.025 cm, 18.633 cm, 20.118 cm, respectively. Fly ash geopolymer has linear attenuation coefficient of 0.1387/cm, 0.1075/cm, and 0.0964/cm, mass attenuation coefficient of 0.0761 cm 2 /g, 0.0589 cm 2 /g, 0.0529 cm 2 /g, HVL of 4.998 cm, 6.453 cm, 7.202 cm, and TVL of 16.603 cm, 21.437 cm, 23.926 cm, respectively. Test samples made from slag-based geopolymers have a better shielding capability compared to fly ash-based geopolymers due to having higher attenuation coefficients as well as lower HVL and TVL, thus requiring less material to absorb radiation of the same energy level.

Measurement of vapor flow in geothermal pipe faces great challenges due to fast fluids flow in high-temperature and high-pressure environment. In present study the flow rate measurement has been performed to characterization the geothermal vapor flow in a pipe. The experiment was carried out in a pipe which is connected to a geothermal production well, KMJ-14. The pipe has a 10" outside diameter and contains dry vapor at a pressure of 8 kg/cm 2 and a temperature of 170 o C. Krypton-85 gas isotope ( 85 Kr) has been injected into the pipe. Three collimated radiation detectors positioned respectively at 127, 177 and 227 m from injection point were used to obtain experimental data which represent radiotracer residence time distribution (RTD) in the pipe. The last detector at the position of 227 m did not respond, which might be due to problems in cable connections. Flow properties calculated using mean residence time (MRT) shows that the flow rate of the vapor in pipe is 10.98 m/s, much faster than fluid flow commonly found in various industrial process plants. Best fitting evaluated using dedicated software developed by IAEA expert obtained the Péclet number Pe as 223. This means that the flow of vapor of geothermal fluids in pipe is plug flow in character. The molecular diffusion coefficient is 0.45 m 2 /s, calculated from the axial dispersion model.