Environmental impact of fluid catalytic cracking unit in a petroleum refining complex

The fluid catalytic cracking (FCC) unit is of great importance in petroleum refining industries as it treats heavy fractions from various process units to produce light ends (valuable products). The FCC unit feedstock consists of heavy hydrocarbon with high sulphur contents and the catalyst in use is zeolite impregnated with rare earth metals i.e. lanthanum and cerium oxides. The catalytic cracking reaction is endothermic and takes place at elevated temperature in a fluidised bed reactor generating sulphur-contaminated coke on the catalyst. In the regenerator, coke is completely burnt producing SO2, particulate matter emissions. The impact of the FCC unit is assessed in the immediate neighborhood of the refinery. Emission inventories for years 2008 and 2009 for both SO2 and PM have been calculated based on real operational data. Comprehensive meteorological data for years 2005 – 2009 are obtained and preprocessed to generate planetary boundary layer parameters using Aermet (Aermod preprocessor). Aermod (US EPA approved dispersion model) is applied to predict ground level concentrations of both pollutants in the selected study area. Model output is validated with the corresponding measured values at discrete receptors. The highest hourly SO2 predicted concentrations for both years 2008 and 2009 exceeded the corresponding Kuwait EPA ambient air standard, mainly due to elevated emission rates and the prevailing calm and other meteorological conditions. The highest daily SO2 predicted concentrations also exceeded the Kuwait EPA allowable limit due to high emission rates, while meteorological parameters influence is dampened. Hourly average predicted PM concentrations showed similar variation into SO2 in different location. The daily average predicted PM concentrations are lower than US EPA specified limit. An extensive parametric study has been conducted using three scenarios, stack diameter, stack height and emission rates. It is noticed that stack diameter has no effect on ground level concentration, as stack exit velocity is a function of the square of stack diameter. With the increase in stack height, the predicted concentrations decrease showing an inverse relation. The influence of the emission rate is linearly related to the computed ground level concentrations SO2 additives are tested for SO2 emissions reduction. In the year 2008, reduction of SO2 annual total emission by 43% results in full compliance with Kuwait EPA hourly specified limit, using an appropriate amount of additives. Similarly, 57% reduction of SO2 annual total emission leads to no exceedance in predicted concentrations for the year 2009. The application of the state of the art technology, ESP has reduced about 90% of PM emissions for the year 2009

Rotational Barrier and Quantification of Electron-Donating Substituent Effects: a Computational Study of para-Substituted Benzaldehydes

The rotational barrier around the phenyl-formyl bond between the minimum and transition states of para-substituted benzaldehydes was computationally studied for 34 electron-donating substituents. The rotational barrier exhibited very good correlation with shortening of the phenyl-formyl bond, lengthening of carbonyl bond, increase of electron density at the formyl group, increase of stabilization energy, lowering of chemical shift in the 13C NMR of the formyl carbon, and with the values of empirical Hammett σp+ constants. Therefore, rotational barrier is a useful quantum mechanical parameter for quantifying the electron-donating substituent effect and π-conjugation in para-substituted benzaldehydes. Based upon the rotational barrier a scale has been set in this work to judge the electron donating effect of substituents. Moreover, a canonical structure has been proposed for stronger electron-donating substituents. The results of this study reveal that simultaneous presence of electron acceptor formyl group and electron-donating groups is mandatory for the extension of resonance stabilization. This work is licensed under a Creative Commons Attribution 4.0 International License

Transition: a concept of significance to nursing and health care professionals

The concept of transition has growing significance within the healthcare settings. Healthcare professionals’ encounters with patients and family during periods of health-illness transitions in addition to other transitions (e.g., developmental) can be significant. Therefore healthcare professionals should be aware of the meaning and the process of transition, to ensure efficient and competent provision of care. This paper will explore the concept of transition in the context of healthcare, and will suggest strategies to enable professionals to manage transition effectively

Effect of Olive Leaves Drying on the Content of Oleuropein

Oleuropein content in olive leaves dried at ambient temperature, and at elevated temperature (50˚C) from Palestinian olive trees collected from West Bank in the middle of November was determined by HPLC and compared to naturally dry olive leaves (collected dry from the tree). Results showed that higher concentration was obtained from olive leaves dried at room temperature (10.0 mg per gram of dry olive leaves), compared to those dried at 50˚C (1.7 mg/g), and those that collected dry from the tree (2.5 mg/g). Oleuropein content of dried olive leaves was compared with leaves that chopped and extracted fresh, and results show that fresh leaves showed the lowest oleuropein content (<0.1 mg/g) denoting that drying of leaves is required for high oleuropein recovery

Optimum Conditions for Oleuropein Extraction from Olive Leaves

In this study the effect of extraction solvent (type, composition, pH, and temperature), and the extraction method (maceration and soxhlet) on the amount of oleuropein extracted from olive leaves obtained from West Bank /Palestine was investigated. It was found that pure solvents (100% water, 100% methanol, and 100% ethanol) are not good solvents for oleuropein extraction, while mixtures of the solvents (methanol/water and ethanol/water) gave higher oleuropein content. It was found that 80% ethanol give the highest oleuropein content followed by 20% acetonitrile. Temperature of extraction was found to have a significant effect on the oleuropein content where higher temperature gave higher oleuropein content. It was found also that the amount of oleuropein extracted decreases with increase in pH where highest amount was obtained at pH 3. Soxhlet extraction was found to give higher oleuropein content compared to maceration method

Optimum Conditions for Oleuropein Extraction from Olive Leaves

In this study the effect of extraction solvent (type, composition, pH, and temperature), and the extraction method (maceration and soxhlet) on the amount of oleuropein extracted from olive leaves obtained from West Bank /Palestine was investigated. It was found that pure solvents (100% water, 100% methanol, and 100% ethanol) are not good solvents for oleuropein extraction, while mixtures of the solvents (methanol/water and ethanol/water) gave higher oleuropein content. It was found that 80% ethanol give the highest oleuropein content followed by 20% acetonitrile. Temperature of extraction was found to have a significant effect on the oleuropein content where higher temperature gave higher oleuropein content. It was found also that the amount of oleuropein extracted decreases with increase in pH where highest amount was obtained at pH 3. Soxhlet extraction was found to give higher oleuropein content compared to maceration method

Inventories of SO2 and particulate matter emissions from fluid catalytic cracking units in petroleum refineries

Fluid catalytic cracking (FCC) of heavy ends to high value liquid fuels is a common unit operation in oil refineries. In this process the heavy feedstock which contains sulphur is cracked to light products. Sulphur content is hence redistributed in the liquid and gaseous products and coke of the catalyst used in this process. The coke is later burnt in the regenerator releasing sulphur into the discharged flue gas as SO2. In the present work, comprehensive emission inventories for a FCC unit in a typical oil refinery are prepared. These inventories are based on calculations which assume complete combustion of catalyst coke in the regenerator. Yearly material balances for both SO2 and particulate matters (PM) emissions are carried out taking into account seasonal variations in the operation of the process unit. The results presented in this paper reflect the variation of sulphur in feedstock originating from various units in the refinery. The refinery operations are not dependant on seasons but controlled by market driven conditions to maximize the profit. The seasonal impact on refinery emissions is minimal due to its operation at optimum capacity fulfilling the international market demand. The data presented and analyzed here can be used to assess the hazardous impact of SO2 and particulate matter (PM) emissions on surrounding areas of the refinery

The Effect of Using the Integrating technology and 3E Learning Cycle in Implementation of Practical Activities on the Achievement of the Eighth-graders in Science

The study objective has been to seek the effect of integrating technology and the 3E Learning Cycle in implementing practical activities on the achievement of the eighth-graders in science and their attitudes towards using it. The study adopted a Quasi-experimental and Descriptive approach. The study participants consisted of (65) students divided into (32) students’ as an experimental group and (33) students as a control group. Pre-test, post-test, and questionnaire were used as the study instruments. The findings revealed that there were statistically significant differences between the experimental group and the control group in favor of the experimental group students. Furthermore, the results confirm that the experimental group students have positive attitudes toward their learning via integrating technology and the 3E Learning Cycle. They demonstrated statistically important amelioration following its implementation. The study recommends conducting further studies related to integrating technology with updated learning cycles on the E3 learning cycle

The Effect of Using the Integrating technology and 3E Learning Cycle in Implementation of Practical Activities on the Achievement of the Eighth-graders in Science

The study objective has been to seek the effect of integrating technology and the 3E Learning Cycle in implementing practical activities on the achievement of the eighth-graders in science and their attitudes towards using it. The study adopted a Quasi-experimental and Descriptive approach. The study participants consisted of (65) students divided into (32) students’ as an experimental group and (33) students as a control group. Pre-test, post-test, and questionnaire were used as the study instruments. The findings revealed that there were statistically significant differences between the experimental group and the control group in favor of the experimental group students. Furthermore, the results confirm that the experimental group students have positive attitudes toward their learning via integrating technology and the 3E Learning Cycle. They demonstrated statistically important amelioration following its implementation. The study recommends conducting further studies related to integrating technology with updated learning cycles on the E3 learning cycle