Wood M.,Cameron International Inc.
GPA Annual Convention Proceedings
The molecular sieve dehydration unit is an important process in any plant that uses natural gas as a feedstock. Molecular sieve dehydration is currently the process by which almost all water is removed from gas. The switching valves (gas in, gas out, regeneration in, regeneration out, pressuring and depressuring) are critical components in this process. A discuzssion covers selection of the proper valve type for use as a molecular sieve switching valve; common pitfalls; construction, start-up, and plant commissioning phases; common problem in the operation of switching valves; turnarounds, shutdowns, repair, and maintenance; and recommendations to extend the operating life on switching valves used in molecular sieve dehydration service. This is an abstract of a paper presented at the 90th Annual Convention of the GPA (San Antonio, TX 4/3-6/2011). Source
Citirik E.,Cameron International Inc.
Journal of Pressure Vessel Technology, Transactions of the ASME
A comprehensive methodology is developed to understand and characterize the fracture behavior of circumferentially cracked boiler tubes in this study. Weld overlay is applied on the coal-fired boiler tubes in order to prevent the degradation of corrosive and erosive environment that the boiler tubes are exposed to in the power plants. Finite element modeling and analysis are employed for all of the computations including steady-state and transient stress intensity factor (SIF) calculations in this study. Circumferential cracking has been one of the failure modes in waterwall boiler tubes, which results in high maintenance and replacement costs. Thermomechanical stresses and corrosive environment are basically the two remarkable contributors that bring about this failure mode. The former one is investigated and quantified in this study in order to explain the fracture behavior of weld overlay coatings during the power plant operation. Periodic soot blowing operations cause cyclic transient thermomechanical stresses on the weld overlay coating that results in crack propagation and fatigue failure. Three-dimensional fracture analysis of circumferentially cracked boiler tubes is examined using enriched finite element method in this study. Transient temperatures and thermomechanical stresses are computed using ANSYS for five different periodic crack spacing values (h), which are 2, 4, 6, 10, and 20 mm in the axial direction. 3D fracture analysis was performed, and stress intensity factors were computed using FRAC3D, which is Finite Element Analysis (FEA) software developed at Lehigh University. The maximum stress intensity factor is obtained at the deepest penetration of the crack in the model which has the largest periodic axial crack spacing, h 20 mm. The stress intensity factors due to welding residuals decrease as the axial crack spacing, h, decreases. The FEA methodology developed in this research would provide the engineers with the ability to understand the fracture problem and predict component life and improve the reliability of the weld overlay coated boiler tubes utilized in the power plants. © 2012 American Society of Mechanical Engineers. Source
Nathan M.L.,University of Texas at Austin |
Nathan M.L.,Cameron International Inc. |
Dyson T.E.,University of Texas at Austin |
Dyson T.E.,General Electric |
And 2 more authors.
Journal of Turbomachinery
There have been a number of previous studies of the adiabatic film effectiveness for the showerhead region of a turbine vane, but no previous studies of the overall cooling effectiveness. The overall cooling effectiveness is a measure of the external surface temperature relative to the mainstream temperature and the inlet coolant temperature, and consequently is a direct measure of how effectively the surface is cooled. This can be determined experimentally when the model is constructed so that the Biot number is similar to that of engine components, and the internal cooling is designed so that the ratio of the external to internal heat transfer coefficient is matched to that of the engine. In this study, the overall effectiveness was experimentally measured on a model turbine vane constructed of a material to match Bi for engine conditions. The model incorporated an internal impingement cooling configuration. The cooling design consisted of a showerhead composed of five rows of holes with one additional row on both pressure and suction sides of the vane. An identical model was also constructed out of low conductivity foam to measure adiabatic film effectiveness. Of particular interest in this study was to use the overall cooling effectiveness measurements to identify local hot spots which might lead to failure of the vane. Furthermore, the experimental measurements provided an important database for evaluation of computational fluid dynamics simulations of the conjugate heat transfer effects that occur in the showerhead region. Continuous improvement in both measures of performance was demonstrated with increasing momentum flux ratio. © 2014 by ASME. Source
Gavanluei A.B.,Cameron International Inc. |
Mishra B.,Colorado School of Mines |
Olson D.L.,Colorado School of Mines
NACE - International Corrosion Conference Series
Corrosion rate of a low alloy tempered martensite downhole tubular steel was studied at different temperatures and CO2 partial pressures using direct weight loss measurement. Experiments were carried out in a high pressure high temperature autoclave. CO2 partial pressures of 40 (276), 80 (552), 160 (1103), and 320 (2206) psi (kPa) were examined at temperatures 25, 40, 50, and 75 °C. A linear trend between corrosion rate and CO2 partial pressure was observed at different temperatures and increasing CO 2 partial pressure increased the slope of the lines. In addition, at constant CO2 partial pressure, increasing temperature increased the corrosion rate. X-ray diffraction (XRD) and scanning electron microscopy (SEM) were used to study the corrosion products formed on the surface. At 50 °C and below, only iron and iron carbide were detected using XRD analysis, but, at 75 °C, in addition to iron carbide, iron carbonate was also detected. Formation of scattered iron carbonate crystals was studied using SEM. Finally, having the corrosion rate at different temperatures and CO2 partial pressures, the activation energy of the corrosion process was calculated using the de Waard Equation. © 2013 by NACE International. Source
Cameron International Inc. | Date: 2010-06-15
In at least some embodiments, an apparatus includes a hydraulic directional control manifold and a plurality of electric piezopumps. The apparatus also includes an electric piezopump controller that operates the plurality of electric piezopumps in varying combinations to provide generation and directional control of hydraulic power to linear hydraulic actuators using localized closed-loop hydraulic fluid.