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Thesis (Ph. D.)--Institute of Paper Chemistry, 1941. / Bibliography: leaves 60-61.

Orientadores: Maria Regina Wolf Maciel, Cesar Benedito Batistella / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Quimica / Made available in DSpace on 2018-08-05T09:50:50Z (GMT). No. of bitstreams: 1 Santos_PaulaSbaiteDuartedos_D.pdf: 13184059 bytes, checksum: 1404cab88adf29540b081166a12b3ec9 (MD5) Previous issue date: 2005 / Resumo: Destilação Molecular é um processo de separação que utiliza alto vácuo, temperaturas de operação reduzidas e curta exposição do material à temperatura operacional. O termo resíduo de vácuo (frações pesadas de petróleo) se refere ao fundo da destilação à vácuo, que tem uma temperatura atmosférica equivalente (TAE) acima de 540oC. A determinação da curva de Ponto de Ebulição Verdadeiro (PEV) é bem estabelecida para frações de petróleos que alcançam o PEV de aproximadamente 565oC por meio da Sociedade Americana de Testes e Materiais. Para temperaturas mais elevadas, não existe, ainda, um método padronizado. O objetivo deste trabalho foi desenvolver um método novo e apropriado para estender a curva PEV para ser utilizada na caracterização de resíduos de vácuo de petróleos pesados. Por meio de um destilador molecular de filme descendente, experimentos foram realizados usando frações pesadas de petróleos brasileiros, onde as temperaturas operacionais foram aumentadas sistematicamente. As frações obtidas em cada uma das temperaturas pré-estabelecidas foram coletadas, quantificadas e caracterizadas para ambas as correntes do destilador. Com uma melhor caracterização dos petróleos brasileiros, que são considerados pesados, será possível aumentar os rendimentos operacionais nas refinarias, além da obtenção de produtos de alto interesse comercial. De acordo com os resultados obtidos, foi possível estender a curva PEV através do processo de Destilação Molecular com boa precisão utilizando a correlação FRAMOL desenvolvida. Isto é de extrema importância, uma vez que permite definir melhores estratégias e condições operacionais para o processamento de petróleo, representando um progresso considerável na análise de frações pesadas de petróleo. Os desenvolvimentos realizados nesse trabalho são muito importantes desde que nenhuma metodologia padronizada está disponível para cálculo da curva PEV estendida e devido à grande quantidade de petróleo pesado encontrado hoje / Abstract: Molecular Distillation is a separation process which explores high vacuum, operation at reduced temperatures and brief exposition of the material to the operating temperature. The term vacuum residue (heavy petroleum fractions) refers to the bottom of the vacuum distillation, which has an atmospheric equivalent temperature (AET) above 540oC. The determination of the True Boiling Point (TBP) curve is well established for petroleum fractions that reach the TBP up to 565°C by the American Society for Testing and Materials (ASTM). Even so, for higher temperatures, these does not exist a standard methodology as yet. The objective of this work is to develop a new and more appropriated method to extend the TBP curve in order to use it for characterizing vacuum residue of heavy petroleum. Through falling film molecular distillator, experiments were carried-out using heavy fractions of Brazilian petroleum, where operating temperatures were increased systematically. The fractions obtained in each one of the pre-established temperatures were collected, quantified and characterized for both streams of the distillator. With a better characterization of the Brazilian petroleum, which is considered heavy, it will be possible to increase the operational yields in refineries, besides obtaining products of greater commercial interest. Regarding the results obtained, it is possible to extend the TBP curve through Molecular Distillation process with very good precision using the FRAMOL / Doutorado / Desenvolvimento de Processos Químicos / Doutor em Engenharia Química

Orientadores: Maria Regina Wolf Maciel, Cesar Benedito Batistella / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Quimica / Made available in DSpace on 2018-08-04T03:08:23Z (GMT). No. of bitstreams: 1 Martins_PatriciaFazzio_M.pdf: 4266626 bytes, checksum: a048f065c12ba7c99e232ca5dd0eb892 (MD5) Previous issue date: 2005 / Resumo: Os destiladores desodorizados de óleos vegetais (DDOV) são constituídos por diversas substâncias, entre elas, os ácidos graxos livres, fitoesteróis, tocoferóis, ésteres de fitoesteróis, hidrocarbonetos, glicerídeos e produtos da decomposição destas moléculas. O teor de ácidos graxos livres (AGL) nos DDOV varia entre 24 e 85%. Devido ao seu alto teor, a separação dos AGL dos destilados desodorizados dos óleos vegetais é uma etapa importante para proceder à concentração de tocoferóis e fitoesteróis em alta pureza. Os tocoferóis são substâncias naturais valiosas usadas em alimentos, cosméticos e fármacos devido às suas propriedades vitamínicas e antioxidantes. Os fitoesteróis têm recebido grande atenção ultimamente, devido à sua atividade anticolerolêmica e potencialidade de aplicação em nutracêuticos. Neste trabalho, foram realizados ensaios para estudar a remoção dos AGL presentes nos destilados desodorizados de óleos vegetais provenientes do refino de óleo de girassol (DDOG) e de canola (DDOC), utilizando o processo de destilação molecular. Para isso, diversas condições operacionais de temperatura do evaporador e da vazão de alimentação foram utilizadas. O objetivo é avaliar o comportamento do sistema e determinar as melhores condições operacionais para realizar a eliminação de ácidos graxos, minimizando as perdas de tocoferóis durante o processo... Observação: O resumo, na íntegra, poderá ser visualizado no texto completo da tese digital / Abstract: Distilates of the vegetable oil deodorization (DVOD) are composed by free fatty acids, phytosterols, tocopherols, phytosterol esters, hydrocarbons, acylglycerols and products of decomposition of these molecules. The content of free fatty acids (FFA) in the deodorizer distillates varies between 24% and 85%. Due to its high content, free fatty acid separation from deodorizer distillate is an important step to concentrate tocopherols and phytosterols in high purity. Tocopherols are valuable natural substances used in food, cosmetic and pharmaceutical industries due to its vitaminic and antioxidant properties. Phytosterols have received grat attention because its hipocholesterolemic properties and potential to be used in nutraceutics. In this work, separation of free fatty acids from sunflower (SuODD) and canola oil (CODD) deodorizer distillates was investigated through molecular distillation. For this, different operating conditions of evaporator temperature and feed flow rate were used. The intention is to evaluate the behavior of the system and to determine the best operating conditions to eliminate FFA, minimizing tocopherol losses during the process. Furthermore, in this work, it was necessary to establish analytical techniques to determine the contents of tocopherols, phytosterols, triacylglycerols, diacylglycerols, monoacylglycerols and free fatty acids in DVOD. Besides, of DDOC and DDOG, the soybean oil deodorizer distillate (SODD) was also characterized... Note: The complete abstract is available with the full electronic digital thesis or dissertations / Mestrado / Desenvolvimento de Processos Químicos / Mestre em Engenharia Química

The vacuum distillation of heat-sensitive substances such as organic oils, dyes, and drugs requires special equipment from that available for atmospheric distillation. Study in the resulting field, high vacuum distillation, has subsequently led to the development of such equipment. Three types of high vacuum distillation and distillation equipment are recognized: conventional distillation, unobstructed-path distillation, and molecular distillation. Conventional vacuum distillation employs standard equipment under relatively high vacuum conditions. For unobstructed-path distillation, the equipment is modified so that the vapor path between the evaporating and condensing surfaces is clear. When the vapor path is unobstructed and the condenser is separated from the evaporator by a distance less than the mean free path of the evaporating molecules, the phenomenon is called molecular distillation. Molecular distillation is the limiting type of high vacuum distillation with the absolute pressure range approximately 1 to 7 microns of mercury. The use of the centrifugal molecular still permits the distillation of organic substances which might suffer thermal decomposition even under the conditions of the conventional high vacuum still. Against the advantages of prevention of thermal decomposition and shorter time requirements must be placed the poor separatory power of distillation and the necessity of numerous redistillations. The molecular still is valuable not because it gives good separation but because distillation is accomplished 50 to 250 degrees centigrade below temperatures of conventional atmospheric distillation. In ideal molecular distillation, equilibrium does not exist between the vapor and the liquid, no molecules re-enter the distilland after once being vaporized. Under these ideal conditions, Langmuir's equation predicts that the quantity of a given material distilling at a given temperature is proportional to P/√M where P is the vapor pressure and M is the molecular weight. Previous investigations at the Virginia Polytechnic Institute and other laboratories substantiate the importance of molecular weight and structure. Since most of these investigations have been only exploratory, insufficient work has been done to permit any conclusions of major importance. The purpose of this investigation was to determine the effects of various molecular structures of fatty acids on their distillation characteristics when distilled in a laboratory-size centrifugal molecular still. Saturated (C₁₅, C₁₆, C₁₇, C₁₈, C₁₉, and C₂₀) and unsaturated (C₁₈ with one, two, and three double bonds) fatty acids were used in the study. Such effects as the chain length, presence of double bonds and their position in the molecule, and cis-trans and positional isomerism were studied. / Ph. D.

The three basic requirements for unobstructed, short path distillation are: a surface over which a think layer of distilland is distributed, a cooler condensing surface in close proximity to the evaporating surface, and a suitable system for evacuating the space between the two surfaces. When the distance of transfer between the evaporating and condensing surfaces is comparable to the mean free path of the vapor molecules in the residual gas, the process is known as molecular distillation. [Continued in document] / Ph. D.

The theory involved in actual distillation phenomena encountered in molecular distillation has, to the present date, been only lightly explored. Scientific research has been replaced mainly with the need for improving the practical applications ot the process. As a result, although few theoretical correlations have been evolved, the present day high-speed centrifugal molecular stills are capable of effecting separations and purifications economically impossible by any other means. Molecular distillation has found wide commercial application in the separation and purification of such normally non-distillable, high molecular weight, thermally unstable substances as vitamins A and E, industrial synthetics, plasticizers, fatty acid dimers, and the like. In investigating the theory underlying molecular distillation, only a few classes of compounds have been used; the most important of these being pilot dyes, and to a lesser extent, fatty acids. The use of the latter class of compounds has been slight, despite their ease of analysis, ready, solubility in various carrier oils, and the availability of a large number of the series for investigative purposes. It was the purpose of this investigation to molecular distill a number of these fatty acids and, from a study of the elimination curves obtained, to determine the effects of molecular weight, molecular structure, and degree of unsaturation on these maxima. The five-inch magnetically-driven centrifugal molecular still employed for the investigation was modified slightly from a previous design. Two metal diffusion pumps which were a part of the vacuum pumping system were replaced by a third megavac forepump, which was in turn connected through a manifold arrangement with the original two that were in the system. A gravity-feed system was also installed; the modification consisted of elevating the feed tank above the still head assembly, and installing a needle valve in the feed line for accurate feed rate control. Preliminary vacuum tests were roads on the modified still, and the development of a synthetic constant-yield oil for use in the investigation was undertaken. From a number of distillation tests made on individual and blended mixtures of various petroleum oils, it was found that a blend of 225 milliliters of Voltesso No 36, 175 milliliters of light mineral, and 425 milliliters of heavy mineral oil distilled in approximately constant volumetric quantities over the temperature range of 86 to 146 degrees Centigrade. The development of a constant-yield oil led to the standardization of an operating procedure which was to be used for all the tests. The operating variables that were held constant for the distillation studies included: feed rate 60 to 65 milliliters per minute; operating pressure, 12 ± 2 microns of mercury; feed-residue temperature difference, 24 ± 1/2 degrees Centigrade; rotor speed, 1000 ± 50 revolutions per minute; condenser water temperature, 45 ± 1 degrees Centigrade; and one pass of the feed mixture across the rotor per fraction. Six saturated fatty acids, pentadecylic, palmitic, margaric, stearic, nonadecylic, and arachidic; one monoethenoid, oleic; and one diethenoid, linoleic, were then individually distilled using the standardized operating procedure devised in the investigation. The elimination curves were plotted and the maxima were found to be 100, 102, 110, 112, 127, 122, 110, 108 degrees Centigrade, respectively. These maxima were then compared to determine what effect molecular weight, molecular structure, and degree of unsaturation had on the maxima. It was concluded from this investigation that the addition of two CH₂ groups in the molecule of a homologous series of long-chain even numbered carbon atom aliphatic fatty acids raises the elimination maximum 10 degrees Centigrade. It was found that no valid prediction as to the effect of the addition of one CH₂ group to a homologous series of long-chain aliphatic fatty acids can be made. The study indicated that molecular structure; that is, chain length, has a definite, but unpredictable influence on the elimination maximum. It was also found that the addition of each unconjugated double bond in a molecule of a homologous series of fatty acids lowers the elimination maximum two degrees Centigrade. / Master of Science

Molecular distillation presents a method of separation for substances of high molecular weights which would suffer thermal decomposition at the higher temperatures that would be required for conventional distillation. In general, the separatory power of molecular stills is poor and in order to obtain relatively pure substances from mixtures, a series of redistillations may have to be performed. The distillation of individual substances under molecular distillation conditions is best characterized by an elimination curve which is a plot of the yield of the substance against the temperature of distillation. Composite curves, similarly, describe the elimination of a mixture of substances. It was the purpose of this investigation to study the distillation characteristics of several anthraquinone dyes by the determination of single and composite elimination curves, and to attempt to separate binary mixtures of dyes by various redistillation techniques. The glass centrifugal molecular still with a five-inch rotor and a ball-jar condensing surface available at the beginning of the investigation was almost completely reconstructed as an all-metal unit employing copper and brass as the materials of construction. Final design included a vacuum-enclosed drive for the rotor. Other modifications included a copper, magnetically-operated feed pump; copper tubing flow lines with silver-soldered connections; copper feed, residue, and distillate reservoir tanks; spark plug leads for heater and motor lead attachments within the vacuum system; feed and residue thermocouples employing copper tubing as part of the copper lead of the copper-constantan hot junction; a silicone gasket for seal of the bell jar to the base plate; a copper feed tube and nozzle; and a vacuum pumping system consisting of two vertical diffusion pumps connected in series and exhausted to two megavac pumps and a hyvac pump to evacuate the distillate tank. Initial tests were made to obtain a constant-yield oil and to standardize an operating technique. A mixture of light and heavy mineral oils was found to be a satisfactory constant-yield oil. Several tests were made using a continuous temperature rise technique in which the distillate fractions were collected as the temperature rose slowly over the collection increment. 1,4-Diethyl-diamineanthraquinone, 1,4-diisopropyldiaminoanthraquinone, and 1,4-dibutyldiaminoanthraquinone dyes were distilled using this method. A discontinuous temperature rise technique replaced the continuous technique when it became evident that this initial technique could not be satisfactorily standardized. Instead of a continuous temperature increase as distillation progressed, the temperature was held constant while fractions were collected for a predetermined time interval required for five nominal passes of the feed across the rotor. A standardized technique was then developed end used for all subsequent tests, The conditions of operation under the technique were as follows: pressure, 6 ± 1 microns of mercury, absolute; rotor speed, 2000 ± 50 revolutions per minute; feed rate, 65 ± 2 milliliters per minute; nominal number of passes of the feed across the rotor for each fraction, 2; and difference between the feed and residue temperatures, 10 degrees Centigrade. The oil solvent, constant-yield oil, was a mixture of 300 milliliters of light mineral oil to 350 milliliters of heavy mineral oil for each test. Three anthraquinone dyes, celanthrene red 3B, 1,4-diethyldiaminoanthraquinone, and 2,6-dimethyldiaminoanthraquinone, were distilled individually using the standardized technique. The elimination curves were plotted and the maxima found to be 121, 152, end 159 degrees Centigrade, respectively. Equal weight binary mixtures of celanthrene red 3B and 1,4-diethyldiaminoanthraquinone, celanthrene red 3B and 2,6-dimethyldiaminoanthraquinone, and 1,4-diethyldiaminoanthraquinone and 2,6-dimethyldiaminoanthraquinone were distilled to study the effect of difference in the temperature interval between elimination maxima on the composite curve. The effect of varying the weight ratio was studied by the distillation of binary mixtures of 2:1, 1:1, and 1:2-1/2 weight ratio of celanthrene red 3B to 1,4-diethyldiaminoanthraquinone. A tertiary mixture of equal weights of the three dyes used in binary mixtures was distilled to note the added complexity of the composite curve. Attempts to separate binary mixtures were made by extractive redistillation in which additional mineral oil was mixed with the cumulative fractions from the original distillation before redistillation and repeated redistillation in which the cumulative fractions were merely redistilled without addition of any more oil. It was concluded from the investigation that each dye in a mixture distills independently of the other dyes preset. The introduction of each two GHZ groups in the 1,4 position of the anthraquinone series was found to increase the elimination maximum by approximately 10 degrees Centigrade. From a study of the composite curves for the various binary mixtures, it was decided that identification of two substances in an unknown mixture was possible if the second substance was in quantity at least 1/6 that of the first substance and had an elimination maximum at least 20 degrees Centigrade different from the first substance. A comparison of the weight per cent of 1,4-diethyldiaminoanthraquinone removed from the mixture with celanthrene red 3B by the two redistillative techniques indicated that extractive redistillation provided better separation than repeated redistillation with 75.5 weight per cent removed from the cumulative fractions up to 140 degrees Centigrade compared to 68.7 and 52.8 weight per cents removed by the first and second redistillations, respectively. / Master of Science

Molecular distillation is that process of free transfer of molecules under high vacuum from an evaporator to a condenser, where the distance of travel is within the limits of the mean free path of the vapor molecules in the residual gas. Under these conditions, distillations can be made at temperatures 100 to 150°C. lower than ordinary distillations. Many of the so-called "undistillables“ can be distilled under conditions existing in the molecular distillation process. The natural fats and waxes, sugar derivatives, petroleum residues, plastics, and plasticizers now fall within the scope of molecular distillation. The use of the molecular distillation process is now limited by the high costs involved. Thermal efficiency is low, only 2% of the total input heat is utilized for distillation. The separating powers of molecular stills are low, never more than that of one ”theoretical plate“. Only those materials that can bear the high process costs are now being produced commercially, the production of vitamins being the most prominent. Considerable work has been done relative to the development of molecular stills. Advancement to the present day centrifugal stills has been accomplished relatively recently. Many problems are yet unsolved. Much work must be done before molecular distillation can be placed on a level with other methods of distillation. An increase in thermal efficiency, an increase in separating powers, a decrease in film thickness, and a lowering of the costs of the process are necessary. The purpose of this investigation was to design and construct a five inch centrifugal molecular still. Four interchangeable rotors were employed, each of different thickness, different diameter, and having a different angle of inclination. The effect of angle of inclination on film thickness can then be studied. Although no data has been published relative to still performance of five inch commercial stills, data obtained from the operation of the still constructed in this investigation can be compared when such data is published. / Master of Science

Orientadores: Maria Regina Wolf Maciel, Cesar Benedito Batistella / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Quimica / Made available in DSpace on 2018-08-05T23:41:15Z (GMT). No. of bitstreams: 1 Fregolente_LeonardoVasconcelos_M.pdf: 590348 bytes, checksum: 2ba3d20d50e05dcaaf811d7862b9cb67 (MD5) Previous issue date: 2006 / Resumo: Monoglicerídeos são emulsificantes amplamente utilizados em alimentos, fármacos e cosméticos. Industrialmente, são produzidos através da interesterificação de triglicerídeos com glicerol, a altas temperaturas (> 200°C), na presença de catalisadores inorgânicos. Também conhecida como glicerólise, esta reação produz uma mistura com aproximadamente 50% de monoglicerídeos. Este nível de concentração é adequado a muitos tipos de aplicações, no entanto, para fabricação de alguns produtos como argarinas, sorvetes e recheios, devem ser utilizados monoglicerídeos de alta concentração (teor mínimo de 90%), os quais são normalmente produzidos através do processo de destilação molecular. Assim, neste trabalho, foi utilizado um destilador molecular centrífugo com área de evaporação igual a 0,0046m2, para a obtenção de monoglicerídeos de alta concentração (até 96,3%). A metodologia de análise de superficie de resposta foi utilizada para a identificação das condições operacionais ótimas de enriquecimento de monoglicerídeos na corrente de destilado. Além disso, um planejamento experimental 23 foi empregado para estudarem-se os efeitos de alguns parâmetros reacionais sobre a concentração de monoglicerídeos na condição de equilíbrio químico da reação de glicerólise de óleo de soja refinado, catalisada por hidróxido de sódio. Então, utilizando-se as condições de destilação otimizadas através da metodologia de análise de superficie de resposta, os produtos reacionais foram destilados, aumentando-se assim a concentração de monoglicerídeos / Abstract: Monoglycerides are emulsifiers widely used in food, harmaceutical, and cosmetic fields. Current industrial processes for monoglycerides production consist on the interesterification of triglycerides with glycerol in the presence of inorganic catalysts at high temperatures (>200°C). This reaction is known as glycerolysis and produces a mixture of approx 50 % of monoglycerides. This leveI of concentration is suitable for many applications, although, some specific uses like margarine, icing and cream filling require distilled monoglycerides, which are purified monoglycerides (min. 90%) normally obtained by molecular distillation processo Therefore, in this work, a centrífugal molecular distillator of evaporation area of 0.0046m2 was used to obtain monoglycerides with up to 96.3% of purity. Response surface methodology was applied as a tool to identifY operating conditions that can lead to higher monoglycerides purity in the distillate stream. Furthermore, a 23 factorial design was employed to evaluate the effects of reaction parameters on the monoglycerides concentration after the interesterification reaction of refmed soybean oil with glycerol in the presence of sodium hydroxide as catalyst. The monoglycerides content in the reaction product was enhanced, using the optimized distillation conditions obtained by the response surface methodology / Mestrado / Desenvolvimento de Processos Químicos / Mestre em Engenharia Química