Emission Minimization of a Two-Stage Sour Water Stripping Unit Using Surrogate Models for Improving Heat Duty Control

Sour water are aqueous waste streams from oil refining operations, heavily contaminated with hydrogen sulfide and ammonia, which need to be stripped before reuse or disposal, avoiding damages to process and environment. Two-stage sour water stripper units are the most common technology to treat sour water for hydrogen sulfide and ammonia separation to produce reusable water and send these species respectively to Claus and ammonia plants. The first stage of a two-stage sour water unit is responsible for properly splitting hydrogen sulfide and ammonia. This work uses surrogate models to predict the limiting point of hydrogen sulfide separation in the first stage of a sour water unit, allowing more efficient heat duty control strategies to achieve the difficult split of hydrogen sulfide and ammonia and simultaneously lowering heat consumption. Failure of compliance to this limit results in unspecified stripped gas from the first stage, impeding it to directed to Claus plant, entailing loss of sulfur production and higher load of pollutant emissions from flared gases. Therefore, a precise surrogate predictor was developed to dynamically define a quasi-optimum set-point to the controller of the first stage reboiler duty based on dynamic disturbances – the first stage input factors to the surrogate model, such as hydrogen sulfide and ammonia contents of the sour water. The new control policy outperformed the traditional first stage ratio control in terms of stripped gas composition and plant stability

A Monte Carlo Methodology for Environmental Assessment Applied toOffshore Processing of Natural Gas with High Carbon Dioxide Content

Offshore production of oil and natural gas with high carbon dioxide content and high gas-to-oil ratio entail stringent processing conditions that require innovations and first-of-a-kind designs, which bear uncertainties derived from the scarcity of commercial-scale projects, hindering to move along technology learning curves. Consequently, unpredicted scenarios and unachieved specifications cause economic and environmental losses. Such uncertainties force offshore plants to be designed under stochastic factors seeking best statistical performance. The Monte Carlo Method is suitable to such finality. This work proposes a computer-aided engineering framework ‘MCAnalysis’ automatically applying a probabilistic environmental assessment of offshore gas processing. ‘MCAnalysis’ integrates HYSYS simulator with ‘Waste Reduction Algorithm’ to assess potential environmental impacts, whose most relevant categories were identified via Principal Component Analysis. An offshore plant processing natural gas with high carbon dioxide content was submitted to probabilistic raw gas flow rate under two scenarios of carbon dioxide content. The higher carbon dioxide content scenario presented the highest probabilistic potential environmental impacts, being the atmospheric category the most relevant

IPC02-27145 A TIME SERIES APPROACH FOR PIPE NETWORK SIMULATION

ABSTRACT We applied time series predicting tools for the simulation of the temporal behavior of large pipeline networks submitted to timely changing inputs. The inputs may consist of a set of specified flow rates at client or supply nodes, while the outputs are another set of nodal pressures and internal flow rates. According to the topology, size, age and history of the network, the continuous generation of phenomenological dynamic simulations may be impossible, imprecise or numerically expensive, demanding thus alternative approaches. Our methodology is particularly oriented to this kind of demand. From recorded network past data covering relevant history of inputs and selected outputs, ARX-MIMO predictors are built with identification methods and launched for continuous estimation of the network outputs one time step ahead. Results are precise enough for engineering, training and monitoring applications

Hypoglycemic and anti-lipemic effects of the aqueous extract from Cissus sicyoides

BACKGROUND: Cissus sicyoides (Vitaceae) is a medicinal plant popularly known in Brazil as "cipó-pucá, anil-trepador, cortina, and insulina". The plant is used in several diseases, including rheumatism, epilepsy, stroke and also in the treatment of diabetes. In the present work, we studied the hypoglycemic and anti-lipemic effects of the aqueous extract prepared from fresh leaves of the plant (AECS), in the model of alloxan-induced diabetes in rats. In addition, hepatic enzyme levels were also determined. RESULTS: Results showed that the daily treatment of diabetic rats with AECS for 7 days (100 and 200 mg/kg, p.o.) significantly decreased blood glucose levels in 25 and 22% respectively, as compared to the same groups before AECS treatment. No significant changes were seen in control diabetic rats before (48 h after alloxan administration) and after distilled water treatment. While no changes were seen in total cholesterol levels, a significant decrease was observed in plasma triglyceride levels, in the alloxan-induced diabetic rats after AECS treatment with both doses, as compared to the same groups before treatment. Significant decreases in blood glucose (25%) and triglyceride levels (48%) were also observed in the alloxan-induced diabetic rats after 4 days treatment with AECS (200 mg/kg, p.o.). Aspartate (AST) and alanine (ALT) aminotransferases levels, in diabetic controls and AECS-treated rats, were in the range of reference values presented by normal rats. CONCLUSIONS: The results justify the popular use of C. sicyoides, pointing out to the potential benefit of the plant aqueous extract (AECS) in alternative medicine, in the treatment of type 2 diabetes mellitus

Desenvolvimento larval de Simulium (Chirostilbia) pertinax (Diptera: Simuliidae) em criadouro artificial

This study aimed to observe the influence of different concentrations of nutrients over the period of development of Simulium (Chirostilbia) pertinax larvae. Were collected Simulium pertinax engorged females and then subjected to oviposition under stress. The eggs were removed and transported to an artificial breeding site, in which two alimentary supplements were compared, viz. algae and yeast in different concentrations. Few variations of abiotic factors were observed during the study, and they were within the standards of the S. (C.) pertinax species. Regarding the rate of pupae formation, a higher concentration of 5 ml of algae + 10 ml of yeast was observed, with significant differences in concentrations of 10 ml of algae and 10 ml of algae and 5 ml of yeast. In tests with 5ml of algae, 10 ml of yeast, and 5 ml of yeast, the end of larval development was not obtained in all replications. The small variation of abiotic factors is consistent with results of other authors, and the values observed in this experiment can be regarded as appropriate when compared to the standards required by this species. Use of seaweed, with or without other elements, for breeding in the laboratoryhas been made by several authors, as well as use of yeast. When S. (C.) pertinax were fed only with culture of algae, larval survival was up to 43 days, and, on the other hand, when fed with yeast broth they did not reach the complete larval development.Key words: Simulium (Chirostilbia) pertinax, larvae development period, larval feeding.Este estudo teve por objetivo observar a influência de diferentes concentrações de nutrientes sobre o período de desenvolvimento larvário de Simulium (Chirostilbia) pertinax. Foram coletadas fêmeas de S. (C.) pertinax ingurgitadas e submetidas à oviposição por “stress”. Os ovos foram retirados e transportados a um criadouro artificial, no qual foram comparados dois suplementos alimentares: alga e levedura, em diferentes concentrações. Poucas variações dos fatores abióticos foram observadas durante o estudo, encontrando-se dentro dos padrões para a espécie S. (C.) pertinax. Em relação à taxa de formação de pupas, foi observada uma maior taxa na concentração de 5 ml de alga + 10 ml de levedura, com diferença significativa em relação às concentrações de 10 ml de alga + 5 ml de levedura. Nos testes com 5 ml de alga, 10 ml de levedura e 5 ml de levedura, não foi obtido o término do desenvolvimento larvário em todas as repetições. A pouca variação dos fatores abióticos é compatível com resultados de outros autores; assim, os valores observados neste experimento podem ser considerados adequados, quando comparados aos padrões exigidos por esta espécie. A utilização de alga, associada ou não a outros elementos, para criação em laboratório, tem sido feita por diversos autores, assim como a utilização de levedura. Em criação de S. (C.) pertinax alimentada com cultura exclusiva de algas, ocorreu sobrevida larvária máxima de 43 dias, e, quando alimentada com caldo de levedura, não obtivemos o desenvolvimento larvário completo.Palavras-chave: Simulium (Chirostilbia) pertinax, período larvário, alimentação larval

Compatibility studies of Olanzapine pre-formulated with excipients by thermal analysis: preliminary study

Thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) were used to investigate drug-excipient interactions and, in consequence, their compatibility. For this purpose, binary mixtures of olanzapine drug substance and the excipients croscarmellose sodium, magnesium stearate and microcrystalline cellulose, were prepared and analysed. By the analysis of the binary mixtures DSC and TG curves it were observed changes on the temperature and enthalpy values of the drug melting and decomposition peak, with the likely formation of intermediate substances.Colegio de Farmacéuticos de la Provincia de Buenos Aire

Crescimento e desenvolvimento da cultura do melão sob diferentes lâminas de irrigação e salinidade da água

Avaliar o crescimento, o desenvolvimento foliar e o acúmulo de matéria seca da cultura de melão Gold mine , submetido a diferentes lâminas de irrigação, utilizando-se água com dois níveis de salinidade, foi o objetivo deste trabalho. O experimento foi conduzido em condições de campo, na Fazenda São João, município de Mossoró, RN, cujo delineamento experimental adotado foi o de blocos casualizados, em esquema fatorial 6 x 2. Os tratamentos consistiram na introdução de seis lâminas de irrigação (0,55; 0,70; 0,85; 1,00; 1,15 e 1,30 da evapotranspiração máxima da cultura) e dois níveis de salinidade da água de irrigação 0,55 e 2,65 dS m-1. A falta de água no período crítico afetou significativamente o restante do ciclo da cultura, causando decréscimo, no peso da fitomassa seca, para lâminas abaixo do tratamento da lâmina padrão (266 mm). O acúmulo de fitomassa foi afetado pela água de maior salinidade (2,65 dS m-1) ao longo de todo ciclo.The aim of this study was to evaluate the growth, vegetative development and accumulation of dry matter of the "Gold mine" melon submitted to different depths of irrigation using two levels of salinity. The experiment was conducted under field conditions at Fazenda São João, Mossoró, RN, in random blocks and 6 x 2 factorial experimental design. The treatments consisted of 6 depths of irrigation (0.55; 0.70; 0.85; 1.00; 1.15; 1.3 of the maximum crop evapotranspiration) and two levels of salinity of the irrigation water (0.55 and 2.65 dS m-1). The absence of water in the critical period significantly affected the rest of the cycle, causing decrease in the dry weight in the treatment of irrigation depth considered as of the most appropriate depth (266 mm). The water of higher salinity (2.65 dS m-1) affected the accumulation of dry matter in the cycle

On the behaviour of spin-orbit connection of exoplanets

Star-planet interactions play, among other things, a crucial role in planetary orbital configurations by circularizing orbits, aligning the star and planet spin and synchronizing stellar rotation with orbital motions. This is especially true for innermost giant planets, which can be schematized as binary systems with a very large mass ratio. Despite a few examples where spin-orbit synchronization has been obtained, there is no demographic study on synchronous regimes in those systems yet. Here we use a sample of 1,055 stars with innermost planet companions to show the existence of three observational loci of star-planet synchronization regimes. Two of them have dominant fractions of subsynchronous and supersynchronous star-planet systems, and a third less populated regime of potentially synchronized systems. No synchronous star-planet system with a period higher than 40 days has been detected yet. This landscape is different from eclipsing binary systems, most of which are synchronized. We suggest that planets in a stable asynchronous spin state belonging to star-planet systems in a supersynchronized regime offer the most favourable conditions for habitability.Comment: 15 pages, 1 figure in main paper, 6 supplementary figures. Published in Nature Astronomy, May 202