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Heat Transfer
Published in Arthur J. Kidnay, William R. Parrish, Daniel G. McCartney, Fundamentals of Natural Gas Processing, 2019
Arthur J. Kidnay, William R. Parrish, Daniel G. McCartney
Reboilers are the primary sources of heat in a distillation column and generate a liquid–vapor mixture by heating the liquid leaving the bottom mass transfer stage or tray. Side reboilers are normally used on demethanizer columns. Their main function is to recover refrigeration over a wider range of temperatures than would be possible with a single bottom reboiler. The Engineering Data Book (2016b) describes four reboiler types: KettleRecirculating thermosyphonPump-throughOnce-through
Two-Phase Flow and Boiling Heat Transfer in Tube Bundles
Published in Satish G. Kandlikar, Masahiro Shoji, Vijay K. Dhir, Handbook of Phase Change: Boiling and Condensation, 2019
Ramin Dowlati, Masahiro Kawaji
A significant portion of all heat exchangers employed in the process and power industries are used to boil pure or liquid mixtures. Many of these heat exchangers involve boiling heat transfer, and hence two-phase (vapor-liquid) cross-flow on the shell-side of horizontal tube bundles. In the chemical and petroleum industries, such equipment is commonly referred to as ‘reboilers,’ or by the more general term, ‘process vaporizers.’ Ultimately, these reboilers add energy to distillation columns, remove energy in refrigeration cycles, or prepare charge for vapor-phase reactions. Kettle-type reboilers (Figure 1), for example, are commonly found at the base of distillation towers. Baffled heat exchangers, such as inverted U-tube steam generators commonly employed in nuclear power reactors, also experience two-phase cross-flow in the top U-bend region.
Basic Concepts: Separation Processes and Other Unit Operations
Published in Victor H. Edwards, Suzanne Shelley, Careers in Chemical and Biomolecular Engineering, 2018
Victor H. Edwards, Suzanne Shelley
Continuous distillation occurs when a continuous flow of a liquid mixture is fed to a distillation column and is separated to produce a continuous flow of bottom product (a liquid stream) from the bottom of the column, and a continuous flow of overhead product (a vapor stream) from the top of the column. The overhead vapor product is then condensed to form a liquid overhead product, or condensate. Part of this overhead product is returned to the top of the column as reflux (the concept of reflux during distillation is discussed in greater detail below). Heat is provided to the bottom of the distillation column to vaporize part of the liquid. The vapor rising from the base of the column is enriched in the more-volatile component. Consequently, the overhead product is also enriched in the more-volatile component(s).
System identification and control of heat integrated distillation column using artificial bee colony based support vector regression
Published in Chemical Engineering Communications, 2022
E. Abdul Jaleel, S. M. Anzar, T. Rehannara Beegum, P. A. Mohamed Shahid
A distillation column is an essential manufacturing unit used to separate liquids or gaseous mixtures into their components, or fractions, based on the differences in boiling point or volatilities. Small and large-scale refineries and petrochemical industries widely employ distillation for 95% of fluid separations (Jaleel and Aparna 2016). It is a high-energy process that utilizes 3% of the world’s total energy consumption (Jana 2010; Mah et al. 1977). There has been immense research to find a reliable and energy-saving process for distilling fluid mixtures (Nakaiwa et al. 1997). It has been observed that an efficient heat integration of two distillation columns would result in greater energy savings (Gadalla 2009; Gadalla et al. 2005; Li et al. 2016; Naito et al. 2000; Nakanishi et al. 1999; Ponce et al. 2015). Heat-integrated distillation column (HIDC) consists of high-pressure and low-pressure columns, with the heat integration between the stripping and rectifying sections. Compared to traditional distillation columns, HIDC requires relatively small capital investments and low operating costs leading to high energy savings and thermodynamic efficiency.
An Improved Restarted Adomian-based Solution for the Minimum Reflux Ratio of Multicomponent Distillation Columns
Published in Indian Chemical Engineer, 2018
M. Danish, M. Mubashshir, S. Zaidi
Distillation columns constitute one of the vital parts of many process industries especially those involved in the separation and purification of multi-component mixtures, for example, petroleum refining, pharmaceutical and food distilling, and many other chemical process plants. An important parameter closely associated with the design of multi-component distillation columns is the minimum reflux ratio and its accurate prediction is important to avoid any ill-design feature, for example, poor separation performance, increased size, and large utility consumption. For quickly assessing the correct value of minimum reflux, several approaches are available in literature [1–3]. Of these approaches, the use of well-known Underwood equations is quite frequent. However, as reported in literature, these equations pose several difficulties in obtaining their solutions because of the presence of nonlinear and singular terms, and various specific methods are employed for overcoming them [4,5]. In one such recently published study [6], an elegant use of powerful analytical method, namely Adomian decomposition method (ADM), was made to predict the approximate analytical solutions for the roots of the Underwood’s equation. The work is remarkable in the sense that it not only exploited the nonlinearity removal properties of ADM but it also intelligently utilised the quick convergence properties of Shanks transformation (STr). This scheme (ADM coupled with STr) was also shown to be computationally simple and reasonably accurate as compared to the well-known Newton–Raphson method (NRM) which suffered from divergence-related issues in case of poor initial guess. Moreover, the scheme, unlike most of the other algorithms, does not require an initial guess and is applicable to all forms of nonlinearities [6–8].
Concentrated Nonequilibrium HD for the Cross Calibration of Hydrogen Isotopologue Analytics
Published in Fusion Science and Technology, 2020
Sebastian Mirz, Tim Brunst, Robin Größle, Bennet Krasch
The distillation column can be operated in two different modes: continuously or in a discontinuous batch mode. The discontinuous distillation process in this column can be described in three steps: 1. The gas mixture is injected from vessel BD701.2.During the injection process, the gas can be chemically equilibrated using a palladium catalyst. At the top of the column, called the condenser, the mixture is condensed. The produced liquid moves downward into the column body. After a sufficientaThe amount of substance is limited by the so-called holdup of the column as the lower limit. The holdup is the minimal amount of substance that is needed to fill the condenser, packing, and reboiler. The additional amount of substance to the holdup depends on the input mixture, intended output mixture, output amount of substance, and separation efficiency.amount of substance is injected, the valves to BD701.2 are closed. The pressure of the column is adjusted and stabilized to typically pt = 0.15 MPa by controlling the flow of the helium coolant and therefore the condenser temperature.2. The liquid accumulates at the bottom of the column,called the reboiler, where it is evaporated by an electric heater. The produced gas stream moves upward into the column body.3. The column body is equipped with a packing mate-rial. This packing provides a high surface area for the contact of the liquid and gas stream. At any point x in the packing, liquid vaporizes and/or gas condensates so that the pressure pt is the sum of the vapor pressures pi of the substances i in the column at this temperature T(x) if the column is in equilibrium. This means that if one follows an amount of substance from the bottom to the top, or from higher to lower temperature. Respectively, the concentration of the substance with the lowest boiling point increases. Similarly, the concentration of the substance with the highest boiling point decreases.