In this work, a custom dynamic mathematical model of an industrial vertical-cylindrical type natural gas fired natural draft heater is developed using gPROMS (R) ProcessBuilder (R). The integrated model comprises sub-...
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In this work, a custom dynamic mathematical model of an industrial vertical-cylindrical type natural gas fired natural draft heater is developed using gPROMS (R) ProcessBuilder (R). The integrated model comprises sub-models for each of the distinct sections of the fired heater which are connected by mass and energy flows. The temperature profiles of the tubular coils and the process fluid, a heat transfer fluid (HTF) are modelled using the distributed parameter system (DPS) in the axial direction (1D). The flue gas temperature in each section is modelled using the lumped parameter approach. Published empirical methods and correlations are used for estimating some unknown model parameters. The resulting model is a system of partial differential-algebraic equations (PDAEs) and serves as a basis for conducting an optimisation study to aid decision-making and to identify the best operating conditions within the specified constraints that minimise the daily operational costs. Through process simulation studies, the model predictions are adjusted to closely approximate collected actual plant data. It is demonstrated through the optimisation study that significant reduction in fuel gas consumption can be achieved compared to the current operating consumption levels. The developed models can be extended for use by other hydrocarbon processing plant operators with slight modifications, by specifying geometric parameters, HTF thermophysical properties, fuel gas composition and properties, among others.
The Rogowski Coil (RC) has air as core around which coil is wound. It works on the principle of Faraday's and Ampere's law. RC can be used to measure both high speed impulse and alternating currents. RC offers...
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ISBN:
(纸本)9781467385886
The Rogowski Coil (RC) has air as core around which coil is wound. It works on the principle of Faraday's and Ampere's law. RC can be used to measure both high speed impulse and alternating currents. RC offers some very important properties like wide bandwidth, galvanic isolation, linearity, lightness and cheap. Presence of all these properties makes RC better than conventional current transducers. It also offers many other applications viz., energy management, protection systems, CT calibration, current sharing, resistance, welding process, measurement of partial discharges and earth resistance of transmission towers. It can measure currents ranging from mili-amperes (mA) to mega-amperes (MA) without any saturation. The construction and measurement conditions decide the application of RC. The eccentricity of coil is the main parameter considered for modelling of RC. The eccentricity effect becomes prominent when the conductor gets displaced away from the centre due to the deviation from circular shape. Change in conductor position affects the measurements done, so this analysis ensures the accuracy of RC. In this paper, eccentricity analysis of RC is done using ANSYS software tool. The observed deviation of mutual inductance during the analysis can be justified with the theoretical existing data.
This work presents a new approach for state-space modeling of distributed parameter transmission line for transient analysis. The lossless line model based on the method of characteristics is used and the state equati...
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This work presents a new approach for state-space modeling of distributed parameter transmission line for transient analysis. The lossless line model based on the method of characteristics is used and the state equations are derived. These equations are converted to a set of difference equations using the trapezoidal rule of integration. By solving these equations, the state of system at discrete time points is obtained. An illustrative example is given and the obtained results are compared with those obtained using conventional methods based on s-domain and fast inverse Laplace transform (FILT). The study also investigates the effects caused by lumped parameter approximation of line losses.
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