DOCSLIB.ORG

Continuous Distillation Theory This Handout Provides Important Information on Filtration Theory and Related Issues

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Continuous Distillation Theory This Handout Provides Important Information on Filtration Theory and Related Issues Continuous Distillation Theory This handout provides important information on filtration theory and related issues: o Continuous Distillation Theory o Determination of Composition by Gas Chromatography o Computer Simulation o Degrees of Freedom/Sensitivity o Material and Energy Balances o Properties o Statistical Analysis o Important Remarks Continuous Distillation Theory The theory is well developed for the prediction of distillation column operations. This section provides an overview of some of the equations and theory associated with continuous distillation. For additional theory development, see Resources. In continuous mode, with feed and distillate and/or bottoms products, lighter components rise up the trays in the column as vapor and are finally liquefied in the condenser. This condensed liquid is either drawn off or reintroduced into the top of the column. Each tray of the column is assumed to be in vapor-liquid equilibrium. Geankoplis (1993) (see Resources) provides excellent diagrams illustrating the flows within a distillation column and the equilibrium on each tray. Several approaches can be taken: • Graphical Methods (McCabe-Thiele method and Ponchon-Savart method) • Shortcut Methods (e.g. Fenske-Underwood-Gilliland method) • Rigorous plate-to-plate calculations (using computer software) The graphical and shortcut methods are specifically for steady state operations. While they do not apply directly to the unsteady operation of a distillation column, they can be useful in initially characterizing a column. For total reflux calculations, the Fenske equation (part of the FUG Shortcut Method) can be used to determine the number of plates required for a given separation. The rigorous plate-to-plate calculations can easily be performed with available computer aided engineering flowsheet simulation programs or special purpose distillation programs. Determination of Composition by Gas Chromatography o You will be injecting 0.1 micro-liter samples o At the beginning of each lab period, inject ethanol, isopropanol, and methanol standards. Note the retention time for each of these peaks. o Use the retention time for the standard peaks to identify peaks from your samples. o Use the relative peak areas of the components in your sample to determine the mass fractions of components in the sample. Computer Simulation Using your knowledge and resources on Continuous Distillation Theory, develop a theoretical basis for predicting steady-state temperatures, pressures, flows, compositions, etc. for your experimental conditions. Use these results to plan your experimental runs then compare your actual results with those predicted. HYSYS is an excellent programming resource for computer simulation of distillation columns. A tutorial is available online at http://hysys.che.ufl.edu/unit_op_lab_examples/index.html Start-up Simulation o Several computer programs are available to perform the dynamic calculations, and return the tray-by-tray characteristics as a function of time. o The HYSYS Plant flowsheet simulation package can be run in dynamic mode for this purpose. o Ideally, you would like to determine the following as a function of time: • distillate product composition • bottoms product composition • stage by stage composition profile • stage by stage flow profile • heat transfer rate to the condenser • heat transfer rate to the reboiler o And determine the • effect of Murphree efficiency on the above • effect of feed plate location on the above • time to reach steady state Steady State Simulation o Several computer programs are available to perform the dynamic calculations, and return the tray-by-tray characteristics as a function of time. o The HYSYS Plant flowsheet simulation package run in steady-state mode is recommended for this. o Ideally, you would like to determine steady-state values for: • distillate product composition • bottoms product composition • stage by stage composition profile • stage by stage flow profile • heat transfer rate to the condenser • heat transfer rate to the reboiler o And determine the: • effect of Murphree efficiency on the above • effect of feed plate location on the above Tray Efficiency Evaluation Determining the efficiency of the trays in the column is an iterative trial and error procedure. First the programs or simulation packages (e.g. in HYSYS Plant simulation) must be setup to simulate the operation of the column. Next, the user guesses the tray efficiencies and the computer performs a tray-by-tray calculation to determine the concentration of the distillate and bottoms products. If the values of the calculated distillate and bottoms concentrations equal to the values found experimentally, then the guessed efficiencies are assumed to be correct. Otherwise, another estimate of the efficiencies is made and the program should be executed again. This is repeated until the predicted product compositions are the same as those determined experimentally. Degrees of Freedom/Sensitivity The main independent variables available for study in the experiments include: • Flow rates (feed, distillate, bottoms) • Steam flow rate • Condenser water flow rate • Feed position Consider effects of changes of these variables on key distillation performance indicators. Note that there are limits to the control of these variables with the equipment available, and not all of these variables will affect performance in a measurable way. Material and Energy Balances Use the experimentally determined compositions and flow rates to determine material balances. Also perform energy balances over the column, around the reboiler, and around the condenser, determining duties and heat transfer coefficients as needed. Resolve any data discrepancies and obtain closure on the material and energy balances. Properties Properties for ethanol and isopropanol are well known. Material and Safety Data Sheets for these major components, as well as methanol, methyl isobutyl ketone, and ethyl acetate, which are present in small amounts, are available for download on the Continuous Distillation Safety webpage. HYSYS DISTIL can be used to create vapor-liquid equilibrium curves for the binary system of ethanol and isopropanol, as well as the ternary system of methanol, ethanol, and isopropanol. Preparation of XY phase diagrams and HXY diagrams for the experimental conditions is strongly recommended. Note the importance of selecting an appropriate property estimation model. Statistical Analysis Apply appropriate statistical procedures to determine the apparent error in results. Important Remarks Whenever possible, measure variables several times and different ways to verify values. .
Load more

Recommended publications
  • Innovation in Continuous Rectification for Tequila Production
    processes Communication Innovation in Continuous Rectification for Tequila Production Estarrón-Espinosa Mirna, Ruperto-Pérez Mariela, Padilla-de la Rosa José Daniel * and Prado-Ramírez Rogelio * Centro de Investigación y Asistencia en Tecnología y Diseño del Estado de Jalisco (CIATEJ), Av. Normalistas No. 800, C.P. 44720 Guadalajara, Jalisco, Mexico; [email protected] (E.-E.M.); [email protected] (R.-P.M.) * Correspondence: [email protected] (P.-d.l.R.J.D.); [email protected] (P.-R.R.); Tel.: +33-33455200 (P.-d.l.R.J.D.) Received: 23 March 2019; Accepted: 6 May 2019; Published: 14 May 2019 Abstract: In this study, a new process of continuous horizontal distillation at a pilot level is presented. It was applied for the first time to the rectification of an ordinario fraction obtained industrially. Continuous horizontal distillation is a new process whose design combines the benefits of both distillation columns, in terms of productivity and energy savings (50%), and distillation stills in batch, in terms of the aromatic complexity of the distillate obtained. The horizontal process of continuous distillation was carried out at the pilot level in a manual mode, obtaining five accumulated fractions of distillate that were characterized by gas chromatography (GC-FID). The tequila obtained from the rectification process in this new continuous horizontal distillation process complies with the content of methanol and higher alcohols regulated by the Official Mexican Standard (NOM-006-SCFI-2012). Continuous horizontal distillation of tequila has potential energy savings of 50% compared to the traditional process, besides allowing products with major volatile profiles within the maximum limits established by the regulation for this beverage to be obtained.
    [Show full text]
  • Page2 Sidebar 1.Pdf
    Headquarters & Forge Americas Office [email protected] [email protected] +49 (0) 7161 / 97830 215.242.6806 +49 (0) 7161 / 978321 fax fax 215.701.9725 artisan distilling systems 600 liter whiskey still the fine art of distillery technology Germany’s oldest distillery fabricator, since 1869, combining traditional family craftsmanship with leading eau-de-vie distillery innovations and technologies. Meticulously custom-crafted artisan copper pot still systems for all the great distilling traditions, and efficient continuous plants, grappa distillery in copper and stainless steel, for all capacities and applications: 450 liter artisan pot stills – brandy & vodka vodka, whiskey, eaux-de-vie, brandy, rum, gin, grappa, tequila, aguardientes… 1000 liter artisan vodka system 650 liter system with CADi automation continuous mash stripping column C. CARL Ziegelstraße 21 Americas Office Brewing & Distilling Ing. GmbH D-73033 Göppingen PO Box 4388 Technologies Corp. www.christiancarl.com Germany Philadelphia, PA 19118-8388 www.brewing-distilling.com CARL artisan distillery systems the fine art of distillery technology CARL custom-builds each distillery to order in our family shop near Stuttgart in Swabia, with the attention and care of crafting a finely- tuned instrument. All-the-while, we stay focused on the continued development of our distillery technology. There are always new ideas and realizations, such our the in-house developed CARL CADi distillery automation or our patented aroma bubble plate technologies, Our innovations have fostered CARL’s nearly 140 years of family tradition and experience as Germany’s oldest and most respected distillery fabricator, with thousands of successful commissions worldwide. form and function Our diverse customers, from small farmers to winemakers to brewers to large spirits houses, show great enthusiasm and appreciation for the aesthetics and functionality of a CARL distillery: its design, its form, classic and intuitively easy to understand, clear in conception.
    [Show full text]
  • Distillation 6
    CHAPTER Energy Considerations in Distillation 6 Megan Jobson School of Chemical Engineering and Analytical Science, The University of Manchester, Manchester, UK CHAPTER OUTLINE 6.1 Introduction to energy efficiency ....................................................................... 226 6.1.1 Energy efficiency: technical issues................................................... 227 6.1.1.1 Heating.................................................................................... 227 6.1.1.2 Coolingdabove ambient temperatures...................................... 229 6.1.1.3 Coolingdbelow ambient temperatures ...................................... 230 6.1.1.4 Mechanical or electrical power.................................................. 232 6.1.1.5 Summarydtechnical aspects of energy efficiency ..................... 233 6.1.2 Energy efficiency: process economics............................................... 233 6.1.2.1 Heating.................................................................................... 233 6.1.2.2 Cooling..................................................................................... 235 6.1.2.3 Summarydprocess economics and energy efficiency ............... 237 6.1.3 Energy efficiency: sustainable industrial development........................ 237 6.2 Energy-efficient distillation ............................................................................... 237 6.2.1 Energy-efficient distillation: conceptual design of simple columns...... 238 6.2.1.1 Degrees of freedom in design ..................................................
    [Show full text]
  • Modelling of Crude Oil Distillation
    Modelling of Crude Oil Distillation Modellering av råoljedestillation JENN Y BEATRIC E SOUC K K T H C h em i ca l S ci en c e and E n gi n e e r i n g Master’s Thesis in Chemical Engineering Stockholm, Sweden 2012 " One never notices what has been done; one can only see what remains to be done" (Marie Curie, 1867-1934) 1 Sammanfattning Under de föhållanden som reservoarens miljö erbjuder, definieras en petroleumvätska av dess termodynamiska och volymetriska egenskaper och av dess fysikalisk-kemiska egenskaper. För att korrekt simulera bearbetningen av dessa vätskor under produktion, deras beteende modelleras från experimentella data Med tillkomsten av nya regler och oflexibilitet som finns på tullbestämmelser vid gränserna idag, har forskningscenter stora svårigheter att få större mängder prover levererade. Av den anledningen, trots att det finns flera metoder för att karakterisera de olika komponenterna av råolja, tvingas laboratorier att vända sig mer och mer till alternativa analysmetoder som kräver mindre provvolymer: mikrodestillation, gaskromatografi, etc. Mikrodestillation, som är en snabb och helt datoriserad teknik, visar sig kunna ersätta standarddestillation för analys av flytande petroleumprodukter. Fördelar med metoden jämfört med standarddestillering är minskad arbetstidsåtgång med minst en faktor 4. Därtill krävs endast en [24] begränsad provvolym (några mikroliter) i jämförelse med standarddestillation. Denna rapport syftar till att skapa en enkel modell som kan förutsäga avkastningskurvan av fysisk destillation, utan att använda mikrodestillationsteknik. De resultat som erhölls genom gaskromatografiska analyser möjliggjorde modelleringen av det vätskebeteendet hos det analyserade provet. Efter att ha identifierat och behandlat praktiskt taget alla viktiga aspekter av mikro destillation genom simuleringar med PRO/II, fann jag att, oberoende av inställningen och den termodynamiska metod som används, det alltid finns stora skillnader mellan simulering och mikro destillation.
    [Show full text]
  • Computer Simulation of a Multicomponent, Multistage Batch Distillation Process
    COMPUTER SIMULATION OF A MULTICOMPONENT, MULTISTAGE BATCH DISTILLATION PROCESS By BRUCE EARL BAUGHER /J Bachelor of Science in Chemical Engineering Oklahoma State University Stillwater, Oklahoma 1985 Submitted to the Faculty of the Graduate College of the Oklahoma State University in partial fulfillment of the requirements for the Degree of MASTER OF SCIENCE July, 1988 \\,~s~ ~ \'\~~ B~~~to'­ <:.o?. ·;)._, ~ r COMPUTER SIMULATION OF A MULTICOMPONENT, MULTISTAGE BATCH DISTILLATION PROCESS Thesis Approved: Thesis Advisor U.bJ ~~- ~MJYl~ Dean of the GradU~te College ABSTRACT The material and energy balance equations for a batch distillation column were derived and a computer simulation was developed to solve these equations. The solution follows a modified Newton-Raphson approach for inverting and solving the matrices of material and energy balance equations. The model is unique in that it has been designed to handle hypothetical hydrocarbon components. The simulation can handle columns up to 50 trays and systems of up to 100 components. The model has been used to simulate True Boiling Point (TBP) diagrams for a variety of crude oils. This simulation is also applicable to simple laboratory batch distillations. The model was designed to accurately combine data files to simulate actual crude blending procedures. The model will combine files and calculate the results quickly and easily. The simulation involves removing material from the column at steady-state. The removal fraction is made small enough to approach continuity. This simulation can be adapted for use on microcomputers, although it will require extensive computation time. ACKNOWLEDGMENTS It has been a great pleasure to work with my thesis advisor, Dr.
    [Show full text]
  • Distillation Handbook
    I distillation terminology To provide a better understanding of the distillation process, the following briefly explains the terminology most often encountered. SOLVENT RECOVERY The term "solvent recovery" often has been a somewhat vague label applied to the many and very different ways in which solvents can be reclaimed by industry. One approach employed in the printing and coatings industries is merely to take impure solvents containing both soluble and insoluble particles and evapo- rate the solvent from the solids. For a duty of this type, APV offers the Paraflash evaporator, a compact unit which combines a Paraflow plate heat exchanger and a small separator. As the solvent ladened liquid is recirculated through the heat exchanger, it is evaporated and the vapor and liquid separated. This will recover a solvent but it will not separate solvents if two or more are present. Afurther technique is available to handle an air stream that carries solvents. By chilling the air by means of vent condensers or refrigeration equipment, the solvents can be removed from the condenser. Solvents also can be recovered by using extraction, adsorption, absorption, and distillation methods. S 0 LV E NT EXT R ACT I0 N Essentially a liquid/liquid process where one liquid is used to extract another from a secondary stream, solvent extraction generally is performed in a column somewhat similar to a normal distillation column. The primary difference is that the process involves two liquids instead of liquid and vapor. During the process, the lighter (i.e., less dense) liquid is charged to the base of the column and rises through packing or trays while the more dense liquid descends.
    [Show full text]
  • Building a Home Distillation Apparatus
    BUILDING A HOME DISTILLATION APPARATUS A Step by Step Guide Building a Home Distillation Apparatus i BUILDING A HOME DISTILLATION APPARATUS Foreword The pages that follow contain a step-by-step guide to building a relatively sophisticated distillation apparatus from commonly available materials, using simple tools, and at a cost of under $100 USD. The information contained on this site is directed at anyone who may want to know more about the subject: students, hobbyists, tinkers, pure water enthusiasts, survivors, the curious, and perhaps even amateur wine and beer makers. Designing and building this apparatus is the only subject of this manual. You will find that it confines itself solely to those areas. It does not enter into the domains of fermentation, recipes for making mash, beer, wine or any other spirits. These areas are covered in detail in other readily available books and numerous web sites. The site contains two separate design plans for the stills. And while both can be used for a number of distillation tasks, it should be recognized that their designs have been optimized for the task of separating ethyl alcohol from a water-based mixture. Having said that, remember that the real purpose of this site is to educate and inform those of you who are interested in this subject. It is not to be construed in any fashion as an encouragement to break the law. If you believe the law is incorrect, please take the time to contact your representatives in government, cast your vote at the polls, write newsletters to the media, and in general, try to make the changes in a legal and democratic manner.
    [Show full text]
  • Batch Distillation of Spirits: Experimental Study and Simulation
    Research article Received: 5 April 2018 Revised: 11 January 2019 Accepted: 15 January 2019 Published online in Wiley Online Library (wileyonlinelibrary.com) DOI 10.1002/jib.560 Batch distillation of spirits: experimental study and simulation of the behaviour of volatile aroma compounds Adrien Douady,1 Cristian Puentes,1 Pierre Awad1,2 and Martine Esteban-Decloux1* This paper focuses on the behaviour of volatile compounds during batch distillation of wine or low wine, in traditional Charentais copper stills, heated with a direct open flame at laboratory (600 L) and industrial (2500 L) scale. Sixty-nine volatile compounds plus ethanol were analysed during the low wine distillation in the 600 L alembic still. Forty-four were quantified and classified according to their concentration profile in the distillate over time and compared with previous studies. Based on the online re- cording of volume flow, density and temperature of the distillate with a Coriolis flowmeter, distillation was simulated with ProSim® BatchColumn software. Twenty-six volatile compounds were taken into account, using the coefficients of the ‘Non- Random Two Liquids’ model. The concentration profiles of 18 compounds were accurately represented, with slight differences in the maximum concentration for seven species together with a single compound that was poorly represented. The distribution of the volatile compounds in the four distillate fractions (heads, heart, seconds and tails) was well estimated by simulation. Fi- nally, data from wine and low wine distillations in the large-scale alembic still (2500 L) were correctly simulated, suggesting that it was possible to adjust the simulation parameters with the Coriolis flowmeter recording and represent the concentration pro- files of most of the quantifiable volatile compounds.
    [Show full text]
  • Design of Multicomponent Heat Integrated Distillation Systems
    DESIGN OF MULTICOMPONENT HEAT INTEGRATED DISTILLATION SYSTEMS LIM RERN JERN A project report submitted in partial fulfilment of the requirements for the award of the degree of Bachelor of Engineering (Hons.) of Chemical Engineering Faculty of Engineering and Science Universiti Tunku Abdul Rahman April 2012 ii DECLARATION I hereby declare that this project report is based on my original work except for citations and quotations which have been duly acknowledged. I also declare that it has not been previously and concurrently submitted for any other degree or award at UTAR or other institutions. Signature : _________________________ Name : ______Lim Rern Jern________ ID No. : ______08UEB04540________ Date : ______April 14, 2012________ iii APPROVAL FOR SUBMISSION I certify that this project report entitled “DESIGN OF MULTICOMPONENT HEAT INTEGRATED DISTILLATION SYSTEMS” was prepared by LIM RERN JERN has met the required standard for submission in partial fulfilment of the requirements for the award of Bachelor of Engineering (HONS) Chemical Engineering at Universiti Tunku Abdul Rahman. Approved by, Signature : _________________________ Supervisor : ____Ms. Teoh Hui Chieh____ Date : _________________________ iv The copyright of this report belongs to the author under the terms of the copyright Act 1987 as qualified by Intellectual Property Policy of University Tunku Abdul Rahman. Due acknowledgement shall always be made of the use of any material contained in, or derived from, this report. © 2012, Lim Rern Jern. All rights reserved. v ACKNOWLEDGEMENTS I would like to express my deepest gratitude and thanks to my project supervisor, Ms Teoh Hui Chieh, for her invaluable advices, support, guidance, patience and time throughout this project. Special thanks to Prof.
    [Show full text]
  • Variety and the Evolution of Refinery Processing Bernard Bourgeois, Phuong Nguyen, Pier Paolo Saviotti, Michel Trommetter
    Variety and the evolution of refinery processing Bernard Bourgeois, Phuong Nguyen, Pier Paolo Saviotti, Michel Trommetter To cite this version: Bernard Bourgeois, Phuong Nguyen, Pier Paolo Saviotti, Michel Trommetter. Variety and the evolu- tion of refinery processing. Industrial and Corporate Change, Oxford University Press (OUP), 2005, 14 (3), p. 469-500. halshs-00003937 HAL Id: halshs-00003937 https://halshs.archives-ouvertes.fr/halshs-00003937 Submitted on 8 Jun 2005 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. VarPetrRef 1 VARIETY AND THE EVOLUTION OF REFINERY PROCESSING Phuong NGUYEN*, Pier-Paolo SAVIOTTI**1, Michel TROMMETTER** and Bernard BOURGEOIS* * CNRS / LEPII-EPE, Université Pierre Mendès-France, BP 47, 38040 Grenoble Cedex 9, France ** INRA / SERD, Université Pierre Mendès-France, BP 47, 38040 Grenoble Cedex 9, France Octobre 2004 Abstract Evolutionary theories of economic development stress the role of variety as both a determinant and a result of growth. In this paper we develop a measure of variety, based on Weitzman's maximum likelihood procedure. This measure is based on the distance between products, and indicates the degree of differentiation of a product population. We propose a generic method, which permits to regroup the products with very similar characteristics values before choosing randomly the product models to be used to calculate Weitzman's measure.
    [Show full text]
  • The Production of Vinyl Acetate Monomer As a Co-Product from the Non-Catalytic Cracking of Soybean Oil
    Processes 2015, 3, 619-633; doi:10.3390/pr3030619 OPEN ACCESS processes ISSN 2227-9717 www.mdpi.com/journal/processes Article The Production of Vinyl Acetate Monomer as a Co-Product from the Non-Catalytic Cracking of Soybean Oil Benjamin Jones, Michael Linnen, Brian Tande and Wayne Seames * Department of Chemical Engineering, University of North Dakota, 241 Centennial Dr., Stop 7101 Grand Forks, ND 58202-7101, USA; E-Mails: [email protected] (B.J.); [email protected] (M.L.); [email protected] (B.T.) * Author to whom correspondence should be addressed; E-Mail: [email protected]; Tel.: +1-701-777-2958; Fax: +1-701-777-3773. Academic Editor: Bhavik Bakshi Received: 30 June 2015/ Accepted: 7 August 2015 / Published: 14 August 2015 Abstract: Valuable chemical by-products can increase the economic viability of renewable transportation fuel facilities while increasing the sustainability of the chemical and associated industries. A study was performed to demonstrate that commercial quality chemical products could be produced using the non-catalytic cracking of crop oils. Using this decomposition technique generates a significant concentration of C2−C10 fatty acids which can be isolated and purified as saleable co-products along with transportation fuels. A process scheme was developed and replicated in the laboratory to demonstrate this capability. Using this scheme, an acetic acid by-product was isolated and purified then reacted with ethylene derived from renewable ethanol to generate a sample of vinyl acetate monomer. This sample was assessed by a major chemical company and found to be of acceptable quality for commercial production of polyvinyl acetate and other products.
    [Show full text]
  • Batch Distillation
    Chapter 7: Batch Distillation In the previous chapters, we have learned the distillation operation in the continuous mode, meaning that the feed(s) is(are) fed continuously into the distillation column the distillation products [e.g., distillate, bottom, side stream(s)] are continuously withdrawn from the column In the continuous operation, after the column has been operated for a certain period of time, the system reaches a steady state 1 At steady state, the properties of the system, such as the feed flow rate the flow rates of, e.g., the distillate and the bottom the feed composition the compositions of the distillate and the bottom reflux ratio (LDo / ) system’s pressure are constant With these characteristics, a continuous dis- tillation is the thermodynamically and economi- cally efficient method for producing large amounts of material of constant composition 2 However, when small amounts of products of varying compositions are required, a batch dis- tillation provides several advantages over the continuous distillation (the details of the batch distillation will be discussed later in this chapter) Batch distillation is versatile and commonly employed for producing biochemical, biomedical, and/or pharmaceutical products, in which the production amounts are small but a very high purity and/or an ultra clean product is needed The equipment for batch distillation can be arranged in a wide variety of configurations 3 In a simple batch distillation (Figure 7.1), va- pour (i.e. the product) is withdrawn from the top of the re-boiler (which is also called the “still pot”) continuously, and by doing so, the liquid level in the still pot is decreasing continuously Figure 7.1: A simple batch distillation (from “Separation Process Engineering” by Wankat, 2007) Note that the distillation system shown in Fig- ure 7.1 is similar to the flash distillation 4 However, there are a number of differences between the batch distillation (e.g., Figure 7.1) and the flash distillation: i.e.
    [Show full text]