<p>The production of chlorate, chlorine and sodium hydroxiderelies heavily on electrical energy, so that savings in thisarea are always a pertinent issue. This can be brought aboutthrough increased mass transfer of reacting species to therespective electrodes, and through increased catalytic activityand uniformity of current density distribution at theseelectrodes. This thesis will present studies involvingmathematical modelling and experimental investigations of theseprocesses. They will show the effect that hydrodynamicbehaviour has on the total current density and cell voltages,along with the effects on current density distributions andindividual overpotentials atthe respective electrodes.</p><p>Primary, secondary and psuedo-tertiary current densitydistribution models of a chlor-alkali anode are presented anddiscussed. It is shown that the secondary model presentsresults rather similar to the pseudo-tertiary model, when thecurrent density distribution is investigated, although thepotential distribution differs rather markedly. Furthermore, itis seen that an adequate description of the hydrodynamicsaround the anode is required if the potential distribution, andthereby the prevalence of side-reactions, is to be reasonablepredicted.</p><p>A rigorous tertiary current density distribution model ofthe chlorate cell is also presented, which takes into accountthe developing hydrodynamic behaviour along the height of thecell. This shows that an increased flowrate gives more uniformcurrent density distributions. This is due to the fact that theincreased vertical flowrate of electrolyte replenishes ioncontent at the electrode surfaces, thus reducing concentrationoverpotentials. Furthermore, results from the model lead to theconclusion that it is the hypochlorite ion that partakes in themajor oxygen producing side-reaction.</p><p>A real-scale cross-section of a segmented anode-cathode pairfrom a chlorate cell was designed and built in order to studythe current density distribution in industrial conditions.These experiments showed that increased flowrate brought aboutmore even current density distributions, reduced cell voltageand increased the total current density. An investigation ofthe hydrodynamic effects on the respective electrodeoverpotentials shows the anode reactions being more favoured byincreased flowrate. This leads to the conclusion that theuniform current density distribution, caused by increasedflowrate, occurs primarily through decreasing the concentrationoverpotential at the anode rather than by decreasing thebubble-induced ohmic drop at the cathode.</p><p>Finally, results from experiments investigating thebubble-induced free convection from a small electrochemicalcell are presented. These experiments show that Laser DopplerVelocimetry is the most effective instrument for investigatingthe velocity profiles in bubble-containing electrochemicalsystems. The results also show that the flow can transform fromlaminar to turbulent behaviour on both the vertical andhorizontal planes, in electrochemical systems where bubbles areevolved.</p>

Universiẗat, Diss., 2003--Stuttgart.

The thesis deals with the issue of possible chlorine leakage from the Aqua Park in the town of Uherské Hradiště. Chlorine is a toxic substance, widely used in industry. The amount of chlorine used in the aqua park does not comply with the values stipulated under the Major Accident Prevention Act, as it is under the limits set in the act and the object therefore cannot be classified into either group A or group B. Since the aqua park falls between unclassified sources, it is not subject to any obligations under this act, including processing documentation for cases of emergency. Despite that it is necessary to ensure the safety of persons in the aqua park area, as well as in its immediate vicinity in case of leakage of large quantities of the substance. The aim of the thesis is to determine whether the aqua park can ensure preparedness for emergencies, especially for chlorine leakage. Chlorine is a moderately toxic substance which irritates particularly the respiratory system, eyes and mucous membranes, and in high concentrations, it can cause pulmonary edema and death. The thesis defines its basic physical and chemical properties, the method of using and providing first aid in case of exposure to the substance. Furthermore, it presents basic concepts related to emergencies and leakages of hazardous substances as well as basic legislation dealing with the issue. Such legislation includes primarily the Act on Integrated Rescue System, Act on Chemical Substances and Mixtures, as well as the Fire Protection Act. The thesis further includes risk assessment and analysis carried out using the Cause-Consequence Analysis or cause-effect analysis. This method is used for a better understanding of failures which can occur in an enterprise. It tries to deal mainly with the evaluation of the probability of system failures and looks for the causes of such failures. Using the Aloha and Terex software programs, a chlorine leak was simulated into the surrounding areas during the summer and winter seasons. Both programs simulated a chlorine leak in the total amount of 975 kg, under the same meteorological conditions for both seasons. Based on the specified input information, endangered zones in which it is necessary to evacuate the people were determined.

Submitted by Maria Medeiros (maria.dilva1@ufcg.edu.br) on 2018-07-06T13:50:36Z No. of bitstreams: 1 CARLOS THIAGO CÂNDIDO CUNHA - TESE (PPGCEMat) 2015.pdf: 3145702 bytes, checksum: bad9f1c620f682b0e77a37c797d9bc37 (MD5) / Made available in DSpace on 2018-07-06T13:50:36Z (GMT). No. of bitstreams: 1 CARLOS THIAGO CÂNDIDO CUNHA - TESE (PPGCEMat) 2015.pdf: 3145702 bytes, checksum: bad9f1c620f682b0e77a37c797d9bc37 (MD5) Previous issue date: 2015-06-22 / Capes / O hidróxido de sódio (NaOH) e o cloro estão entres os produtos químicos mais importantes na indústria e são produzidos simultaneamente pela eletrólise da salmoura. As células eletrolíticas são compostas de uma câmara catódica e uma anódica, separadas por um diafragma que permite a passagem dos íons por migração iônica. A maioria dos diafragmas se utilizam de amianto e as leis ambientais vigentes direcionam para extinção ou substituição deste material. Assim, foi realizado um estudo sobre o desenvolvimento de diafragmas alternativos à base de materiais poliméricos e aditivos que pudessem substituir o amianto e possibilitassem sua aplicação na indústria de cloro-soda. Para tanto, empregou-se fibras poliméricas, a exemplo do Polietileno de Ultra Alto Peso Molecular (PEUAPM), que resiste as condições severas do processo eletrolítico. Também se fez necessário o emprego da dopagem com carga inorgânica (argilas) para conferir menor permeabilidade aos diafragmas. Diante disso, foram desenvolvidos sistemas para deposição e caracterização dos diafragmas que possibilitam a reprodutividade e análises adequadas comparadas ao âmbito industrial. Partindo de um planejamento experimental de misturas com 5 diferentes fibras pode-se avaliar qual composição de diafragma favoreceu melhores resultados nos parâmetros da eletrólise. Os resultados se mostraram promissores, tendo em vista que dentre as 15 formulações testadas conseguiu-se chegar a uma composição cujas propriedades eletroquímicas atendem todas as especificações podendo inclusive ser aplicado em escala industrial. / Sodium hydroxide (NaOH) and chlorine are among the most important chemicals in industry and are produced simultaneously by the electrolysis of brine. Electrolyte cells are consisted by a cathodic and anodic chamber, separated by a diaphragm that allows the passage of ions by ion migration. Most diaphragms using asbestos and environmental laws in use direct to extinction or replacement of this material. In this way, it was done a study on the development of alternative diaphragm based on polymeric materials and additives that could replace the asbestos and could allow its application in chlorine-soda industry. So, polymeric fibres was used, such as, Ultra High Molecular Weight polyethylene (UHMWPE), resisting the harsh conditions of the electrolytic process. Also it was studied the use of doping with inorganic fillers (clays) to provide less permeability to the diaphragms. For this, systems were developed for deposition and characterization of diaphragms that make it possible the reproducibility and suitable analysis compared to the industrial scope. Starting from experimental planning of mixtures with 5 different fibers, it was evaluated which composition of diaphragm given best results in the electrolysis parameters. The results were promising, considering that among the 15 formulations, it was reached a composition whose electrochemical properties meet all specifications and can even be applied on an industrial scale.

Yes / The chlor-alkali industries produce caustic soda (NaOH), chlorine (Cl2 ), and hydrogen (H2 ) as primary products. In 2021, the global chlor-alkali market was valued at $63.2 billion. The article evaluates the global aspects of chlor-alkali industries and prospects for Bangladesh. The current production capacity of NaOH from the chlor-alkali industries in Bangladesh is around 282,150 metric tons/year (MT/y). The by-products, chlorine (Cl2 ) of 250,470 MT/y and hydrogen (H2 ) of 7055 MT/y, are produced domestically. The local demand of Cl2 is 68,779 MT/y. However, there are no systematic utilizations of the residual Cl2 and vented H2 , which threatens the sustainability of the chlor-alkali industries. The article prefigures that a 150,000 MT/y PVC plant can utilize 45.2 % of residual Cl2 of chlor-alkali plants, which would be an economical and environmental milestone for Bangladesh. The residual Cl2 can earn revenue of 908 million USD/y, which can be utilized to import ethylene. For the sustainable utilization of vented H2 , production of H2O2 , fuel cell electric vehicle (FCEV) and H2 fuel-cell-based power plant are the feasible solutions. Thus, for the long-term growth of the chlor-alkali industry in Bangladesh and other developing countries, systematic utilization of Cl2 and H2 is the only feasible solution. / This research was funded by ‘BUET Chemical Engineering Forum (BCEF), 001-2020.

HCl ist ein Nebenprodukt bei vielen organischen Chlorierungsprozessen. Die Aufarbeitung von HCl wäre wirtschaftlich sinnvoll. Eine der möglichen Optionen ist die Rückgewinnung des Chlors durch die katalytische HCl-Oxidation mit O2 (Deacon-Prozess). Das Hauptziel dieser Arbeit war es, die katalytische Aktivität von kupferchlorid-haltigen Schmelzen in Abhängigkeit von der Temperatur und dem Verhältnis der Reaktionsgase zu untersuchen. Dazu wurden Versuche unter stationären und instationären Reaktionsbedingungen im Temperaturintervall zwischen 400 und 500 °C durchgeführt. Für das bessere Verständnis des Katalysator-Systems wurde ein thermodynamisches Modell für das Stoffsystem MeCl-CuCl-CuCl2-CuO-HCl-H2O-Cl2-O2 (Me = Li, Na, K) erstellt. Weiterhin wurden mithilfe von kinetischen Untersuchungen Hinweise auf die Rolle der gelösten oxidischen Zwischenverbindungen im stufenweisen Reaktionsmechanismus gefunden. Mit den Versuchsergebnissen wurde gezeigt, dass die MeCl-CuCl-CuCl2-Schmelzen eine genügende katalytische Aktivität besitzen und damit eine Alternative zu den mit Feststoffträgern arbeitenden Katalysatoren darstellen. Zur Minderung von Korrosionsproblemen wurden mehrstufige Prozessführungen kritisch diskutiert.:1 Einleitung. . . . . . . . . . .7 2 Theoretische Grundlagen zum Deacon-Prozess in Salzschmelzen. . . . . . . . . . .9 2.1 Thermochemie des Deacon-Prozesses. . . . . . . . . . .9 2.1.1 Oxidation von HCl mit O2 ohne Katalysator. . . . . . . . . . .9 2.1.2 Oxidation von HCl mit O2 in Gegenwart von CuCl2-haltigen Katalysatoren. . . . . . . . . . .10 2.2 Kinetik der Teilreaktionen in kupferchlorid-haltigen Salzschmelzen. . . . . . . . . . .13 2.2.1 Zersetzung des CuCl2. . . . . . . . . . .14 2.2.2 Oxidation von CuCl. . . . . . . . . . .15 2.2.3 Reaktion zwischen CuO-haltiger Schmelze und Chlorwasserstoff. . . . . . . . . . .17 3 Thermodynamische Modellierung der Mischungen aus LiCl, NaCl, KCl, CuCl und CuCl2. . . . . . . . . . .19 3.1 Thermodynamische Daten der reinen Stoffe. . . . . . . . . . .20 3.2 Mischungsmodelle. . . . . . . . . . .22 3.3 Vorgehensweise bei der Optimierung. . . . . . . . . . .25 3.4 System LiCl-NaCl-KCl. . . . . . . . . . . 25 3.5 System LiCl-CuCl. . . . . . . . . . .26 3.6 System NaCl-CuCl. . . . . . . . . . .28 3.7 System KCl-CuCl. . . . . . . . . . .29 3.8 System LiCl-CuCl2. . . . . . . . . . .30 3.9 System NaCl-CuCl2. . . . . . . . . . .33 3.10 System KCl-CuCl2 . . . . . . . . . . .34 3.11 System CuCl-CuCl2. . . . . . . . . . . 35 3.12 Ternäre Systeme. . . . . . . . . . .39 4 Untersuchungen zur CuO-Löslichkeit und der Stabilität von Oxidchloriden des Kupfers. . . . . . . . . . .46 4.1 Präparation von Cu2OCl2 und K4Cu4OCl10. . . . . . . . . . .46 4.2 Untersuchungen zur CuO-Löslichkeit. . . . . . . . . . .47 4.2.1 Thermodynamische Reaktionsdaten. . . . . . . . . . .47 4.2.2 Auswertung der Literatur. . . . . . . . . . .48 4.2.3 O2-Titration kupferchlorid-haltiger Schmelze. . . . . . . . . . .49 4.2.4 Hochtemperatur-Filtration und CuO-Analyse. . . . . . . . . . .53 4.2.5 Thermischer Zerfall von Cu2OCl2. . . . . . . . . . .55 4.2.6 Thermischer Zerfall von K4Cu4OCl10. . . . . . . . . . .57 4.3 Thermodynamische Modellierung CuO-haltiger Systeme. . . . . . . . . . .59 4.3.1 Cu2OCl2. . . . . . . . . . .59 4.3.2 K4Cu4OCl10. . . . . . . . . . .60 4.3.3 CuO-Löslichkeit. . . . . . . . . . .62 4.3.4 Salzschmelzenmodell mit oxidhaltigen Systemen. . . . . . . . . . .63 4.4 Thermochemie des Deacon-Prozesses mit Modell-Daten. . . . . . . . . . .69 5 Experimentelle Untersuchungen zur katalytischen Oxidation von HCl in Salzschmelzen. . . . . . . . . . .72 5.1 Versuchsprogramm. . . . . . . . . . .72 5.2 Allgemeine Vorgehensweise. . . . . . . . . . .72 5.2.1 Versuchsapparatur. . . . . . . . . . .72 5.2.2 Vorbereitung der Salzmischungen. . . . . . . . . . .74 5.2.3 Bestimmung der Gaszusammensetzung und Umsatzberechnungen. . . . . . . . . . .75 5.2.4 Bestimmung der Schmelzenzusammensetzung. . . . . . . . . . .77 5.2.5 Charakteristik der Reaktoreinsätze Spirale und Fritte. . . . . . . . . . .77 5.3 Versuche mit Salzmischungen auf der Basis von Kupferchlorid. . . . . . . . . . .81 5.3.1 Stationäre Strömungsverhältnisse. . . . . . . . . . .81 5.3.2 Instationäre Bedingungen. . . . . . . . . . .95 6 Vorschläge zur Technologie. . . . . . . . . . .106 7 Zusammenfassung. . . . . . . . . . .112 Literaturverzeichnis. . . . . . . . . . .115 Anhang. . . . . . . . . . .124 A.1 Thermodynamische Standard-Daten. . . . . . . . . . .124 A.2 Thermodynamische Daten für das Modell LiCl-NaCl-KCl-CuCl-CuCl2-CuO-H2O-HCl-O2-Cl2. . . . . . . . . . .126 A.3 Charakteristika der kupferoxidhaltigen Verbindungen. . . . . . . . . . .133 A.3.1 P-XRD- und Raman-Aufnahmen der synthetischen Oxidchloriden. . . . . . . . . . .133 A.3.2 O2 -Titration kupferchlorid-haltiger Schmelze. . . . . . . . . . .134 A.3.3 Thermischer Zerfall von Cu2OCl2 und K4Cu4OCl10. . . . . . . . . . .137 A.3.4 Phasendiagramm KCl-CuCl2-CuO. . . . . . . . . . .138 A.4 Katalytische Oxidation von HCl in Salzschmelzen. . . . . . . . . . .138 A.5 Physikalische Eigenschaften von (Alk-Cl)-CuCl-CuCl Salzschmelzen. . . . . . . . . . .156 A.6 Chemikalien. . . . . . . . . . .161 A.7 Geräte, Anlagen. . . . . . . . . . .162 A.8 Methode zur titrimetrischen Bestimmung von Cu+, Cu+2 und CuO. . . . . . . . . . .164 A.9 Berechnete Chlor- und Sauerstoffpartialdrücke für (Alk-Cl)-CuCl-CuCl2-Schmelzen. . . . . . . . . . .164 A.10 Berechnete Aktivitäten der geschmolzenen Kupferchloride in (Alk-Cl)-CuCl-CuCl2-Schmelzen. . . . . . . . . . .171

The objectives of this study were to investigate the difference and interaction of mercury (Hg) and selenium (Se) among fish species and tissues. In addition, by comparing with the detected concentrations in other regions, it would be possible to evaluate the pollution status. In the meanwhile, this study analyzed the edibility of the fish, the interaction between Hg and Se as well as their impacts on fish growth. Ten species of fish, including tenpounder (Elops machnata), fourlined terapon (Pelates quadrilineatus), whipfin silverbiddy (Gerres filamentosus), common ponyfish (Leiognathus equulus), Hamilton's thryssa (Thryssa hamiltonii), tilapia (Orechromis niloticus), western Pacific gizzard shad (Nematalosa come), large-scaled mullet (Liza macrolepis), flathead mullet (Mugil cephalus) and milkfish (Chanos chanos), and 20 sediment samples were collected from September to October of 2003 at the reservoir adjacent to a chlor-alkali plant, which had been abandoned for 22 years in Tainan City. Total mercury (THg) and organic mercury (OHg) concentrations were determined in fish muscles, livers, kidneys, gonads, gills and sediment samples. Besides, Se concentrations were also analyzed in fish muscles and livers. Concentrations (mg/kg dry wt.) of THg and OHg in sediment were 43.2¡Ó23.4(mean¡Ósd) and 0.013¡Ó0.008, respectively. THg, OHg and Se concentrations (mg/kg wet wt.) in fish muscles were 0.432¡Ó0.360, 0.305¡Ó0.206 and 0.126¡Ó0.030, similar to the concentrations in other chlor-alkali polluted regions. With the diet habit of Taiwanese, the Hg concentrations of muscles in the seven fish species exceeded the limit of Hg which was allowed to be consumed by humans. THg and OHg concentrations in the fish muscles showed significant species difference. Obviously, the concentrations in carnivorous fishes were higher than those in omnivorous and herbivorous fishes. The OHg concentrations of fish livers and kidneys were highest in carnivorous fishes, but the THg concentrations were higher in omnivorous fishes than in that of carnivorous and herbivorous fishes. Besides, Se concentrations in fish muscles and livers also showed significant species difference, but did not show relation with the feeding habit of fishes. The Hg levels among fish tissues were highest in livers or kidneys, followed by gonads and muscles, lowest in gills. Generally speaking, Se levels were higher in livers than in muscles. The liver THg concentrations of tilapia reached 10 mg/kg wet wt. Their muscle THg concentrations decreased suddenly and maintained at a level about 0.4 mg/kg wet wt. Meanwhile, the liver inorganic Hg and Se concentrations increased with fish weight, while the liver OHg concentrations did not show such a trend but stay at a low level. High Hg concentrations in the fish tissues resulted in adverse effects on fish health. High Hg concentrations in muscles and livers caused heptasomatic index to decrease in western Pacific gizzard shad and milkfish, and condition factor declined in tilipia. Moreover, gonasomatic index remained low while the Hg concentrations of muscles, livers and gonads reached a threshold, which suggested that the growth of those fishes was likely inhibited in Hg polluted environment.

Die Pyrolyse ausgewählter Polysiloxane und Poly(chlor)silane erzeugt meso- und mikroporöses SiC, welches als Hochtemperatur-beständiges Material für Filter, Katalysatorträger und Sensoren ein hohes Anwendungspotential besitzt. Der Pyrolyseprozess bis 1500 °C wird thermogravimetrisch und massenspektrometrisch verfolgt und die resultierenden &amp;quot;Bulk&amp;quot;-Pyrolysate mittels DRIFT-Messungen, Elementaranalyse, XRD, N2-Adsorption und FESEM charakterisiert. Zusammensetzung, Kristallinität und Poreneigenschaften des precursorabgeleiteten SiC lassen sich über die Precursorart sowie über die Pyrolysetemperatur und -dauer steuern. Die Poren entstehen je nach Precursor zwischen 1200 und 1500 °C. Im Falle von mesoporösen Pyrolysaten wird die Porenbildung in erster Linie durch die Abgabe gasförmiger Reaktionsprodukte hervorgerufen. Die Porengrößen dieser Produkte liegen zwischen 6 und 12 nm und die spezifische Oberfläche beträgt bis zu 270 m2/g. Bei den mikroporösen Pyrolysaten, gekennzeichnet durch Poren von 1,5 nm Größe und spezifischen Oberflächen bis 530 m2/g, werden die Poreneigenschaften vor allem durch den im Überschuss vorhandenen elementaren Kohlenstoff geprägt.

This thesis deals with the urgent and follow-up measures in case of chlorine leak and a retrospective analysis of past cases. Chlorine is a widely used toxic gas. It is known from history as the first practically used warfare agent. Today, it is an important chemical raw material that is used widely in industry. It is also commonly transported by road and rail. It is one of the substances whose leakages occur very often. The objective of this paper is to assess the impacts of chlorine leakage on the lives and health of people and to provide an overview of urgent and follow-up measures in case of chlorine leakage in the perspective of the integrated rescue system and the general public. In addition, to locate, describe and analyze past cases. The theoretical part contains information about chlorine, the principles of behaviour of the population in case of an accident with chlorine leakage and an overview of measures undertaken at the site of chlorine leakage. Through studying available literature and resources on the Internet, overview of major chlorine leakages in the Czech Republic as well as abroad has been created. Selected events are described in detail. The practical part simulates, using computer programme called TerEx, a chlorine leakage from a water treatment plant in Písek, South Bohemia. To compare the results, several model situations were created with varying amounts of chlorine leaked at different times of accident and atmospheric conditions. A specific example is used to assess the risks to people living near the plant and to outline the urgent and follow-up measures.

Submitted by Lucienne Costa (lucienneferreira@ufcg.edu.br) on 2018-04-24T00:19:47Z No. of bitstreams: 1 JULIANA ZEYMER AUAD PAFFER – DISSERTAÇÃO (PPGEQ) 2015.pdf: 2369945 bytes, checksum: 31ce517399cfe89bebdd0e7c02c68852 (MD5) / Made available in DSpace on 2018-04-24T00:19:47Z (GMT). No. of bitstreams: 1 JULIANA ZEYMER AUAD PAFFER – DISSERTAÇÃO (PPGEQ) 2015.pdf: 2369945 bytes, checksum: 31ce517399cfe89bebdd0e7c02c68852 (MD5) / Um dos efluentes gerados na indústria de cloro e soda é uma corrente ácida (água saturada de cloro). Esta corrente deve passar por um sistema de tratamento antes de ser descartado, devido ao potencial de dano que este pode causar à flora e à fauna marinha, além de infringir as regulamentações ambientais. Visando reduzir o consumo de energia e atender à especificação do efluente, o objetivo deste trabalho é realizar e avaliar a simulação dinâmica de um sistema de tratamento de efluente ácido. O sistema estudado é composto por uma coluna de stripper e um trocador de calor que pré aquece a corrente de alimentação. O estudo se concentrou em avaliar o comportamento do sistema no estado estacionário e dinâmico frente a alterações nas condições de operação do trocador de calor. As simulações foram realizadas no AspenTM e validados com dados da planta industrial. De acordo com os resultados, reduzindo a eficiência de troca de calor do trocador leva no aumento do consumo de energia e o efluente fica fora das especificações. Desta forma, é muito importante manter a eficiência do trocador de acordo com a de projeto e os controladores sintonizados. / One of the effluents generated by chlor-alkali plant is an acid stream (saturated water chlorine). This stream must pass through a treatment system before being discarded because of damage potential that this may cause to the flora and marine fauna, in addition to breaching environmental regulations. In order to reduce energy consumption and meet the effluent specification, the objective is to implement and evaluate the dynamic simulation of an acid wastewater treatment system. The system is composed of a column stripper and a heat exchanger that heats the pre feed stream. The study focused on evaluating the system behavior in the steady state and dynamic against changes in operating conditions of the heat exchanger. The simulations were accomplished by the simulator Aspen™ and validated with data from industrial plant. According to the results, reducing the efficiency of heat exchanger can make the power consumption increase and the effluent is out of specification. This way, it is very important to keep the heat exchange efficiency according to design and tuned controls.