Impact of Industrial Atmospheric Emissions on Ambient Air Quality in Arzew Area, Oran State, Algeria

This work focuses on identifying the source of BTEX (Benzene, Toluene, Ethylbenzene, Xylene) emissions generated by hydrocarbon-related industrial activities and evaluation of its impact on ambient air quality according to European Union (EU) regulations during 2019. The spatial distribution of BTEX concentrations suggest that massive emissions are mainly due to the oil refining activity. BTEX concentration levels at the sampling sites show that benzene was more dominant. Considering the level of atmospheric pollution relative to the indicative value (2µg/m3) recommended by the EU, the ambient air is considered to be quite polluted with benzene content (5.36 µg/m3) produced mainly by emissions from the oil refining industrial complex.

Box Experiment Study of Thermally Enhanced SVE for Benzene

In order to describe the changes of soil temperature field, air flow field and remediation situation with time during the process of thermally enhanced SVE (soil vapor extraction), a remediation experiment of benzene contaminated soil with single extraction pipe was carried out in a box device. The results showed that the whole temperature of the system was raised to 80 °C in 4 h. 43% of benzene were removed in the first 2% of the extraction time. After 24 h, the repair efficiency was close to 100%. The device can efficiently remove benzene from soil. By continuously monitoring the parameters in the operation process of the system, the spatial distribution of temperature and soil gas pollutant concentration with time was plotted. It showed the benzene concentration distribution in the soil gas was more consistent with the temperature distribution before the start of ventilation, and the concentration of benzene in the soil gas dropped rapidly after ventilation, while the temperature distribution was almost unaffected. In the treatment of soil with a benzene content of 17.8 mg∙kg−1, when the soil gas benzene concentration is the highest at 180 min, the peak value is 11,200 mg∙m−3, and the average concentration is 7629.4 mg∙m−3.

Pre-fractionation concept in the scheme of straight--naphtha fractionation

The requirements to motor fuels are tightened, in particular, restrictions on the content of hydrocarbons and benzene, with the adoption of new emission standards in the modern oil refining industry. At many Russian refineries problem of benzene content decreasing in reformate, which is the main component of gasolines, and, consequently, problem of benzene content decreasing in commercial gasoline, is solved by increasing the initial boiling point of the feedstock for catalytic reforming units to 100°C. At the same time, the main benzene-forming components have boiling points up to 85˚С. This approach is explained by the limitations of technological equipment and a significant increase in energy consumption when creating proper sharpness of rectification at CDU units, while it has a negative impact on the refinery economic efficiency. The article is devoted to approach to modernization of the typical straight-run naphtha distillation unit, configured to the maximum extraction of feedstock for catalytic reforming unit while meeting the requirements imposed on the content of benzene and benzene precursors in it. The proposed solutions can be implemented in the unit current configuration and do not require replacement of main process equipment. Changes in material balance and utility consumption of the unit after described modernization are presented.

E-cigarettes and health risks: more to the flavour than just the name

Rationale: The growing interest in regulating flavoured E-liquids must incorporate understanding of the "flavouring profile" of each E-liquid - which flavourants (flavouring chemicals) are present and at what concentrations not just focussing on the flavour on the label. Methods: We investigated the flavouring profile of 10 different flavoured E-liquids. We assessed bronchial epithelial cell viability and apoptosis, phagocytosis of bacteria and apoptotic cells by macrophages after exposure to E-cigarette vapour extract (EVE). And validated in normal human bronchial epithelial cells (NHBE) and alveolar macrophages (AMs) from healthy donors. We also assessed cytokine release and validated in the saliva from E-cigarette users. Results: Increased necrosis/apoptosis (16.1-64.5% apoptosis) in 16HBE cells was flavour dependent, and NHBEs showed an increased susceptibility to flavours. In THP-1 differentiated macrophages phagocytosis was also flavour dependent, with alveolar macrophages (AM) also showing increased susceptibility to flavours. Furthermore, Banana and Chocolate were shown to reduce surface expression of phagocytic target recognition receptors on alveolar macrophages. Banana and Chocolate increased IL-8 secretion by NHBE, whilst all 4 flavours reduced AM IL-1β secretion which was also reduced in the saliva of E-cigarette users compared with healthy controls. Flavourant profiles of E-liquids varied from simple 2 compound mixtures to complex mixtures containing over a dozen flavourants. E-liquids with high benzene content, complex flavouring profiles, high chemical concentration had the greatest impacts. Conclusions: The flavourant profile of E-liquids is key to disruption of the airway status quo by increasing bronchial epithelial cell apoptosis, causing alveolar macrophage phagocytic dysfunction and altering airway cytokines.

National and sub-national estimation of benzene emission trend into atmosphere in Iran from 1990 to 2013

Introduction: Exposure to benzene has been associated with a range of acute and long-term adverse health effects. We aimed to estimate national and provincial level of benzene emissions from 1990 to 2013 in Iran. Materials and methods: Benzene emission was estimated through two main sources: unburned benzene content of fuel and evaporated benzene. Unburned benzene content of fuel estimated by gasoline consumption rate, kilometers traveled by non-diesel-based cars, and benzene emission factor. Evaporated benzene estimated by evaporated gasoline and volumetric percentile of benzene. Results: The estimated provincial annual mean benzene estimation range was between 5.9 (ton) and 1590 (ton) from 1990 to 2013. Our results showed that maximum benzene emission over the past 24 years occurred in Tehran, (Mean± SD) (1147.2±308.5) (ton)), Isfahan (423.4±132) (ton)), Khorasan Razavi (410.4±122.2) (ton)) provinces, respectively. There was an upward trend in the benzene emission into atmosphere at national and subnational level from 1990 to 2007. Also a significant decrease trend is observed from 2008 to 2013. Conclusion: The findings of this study will provide an insight into the extent of emitted benzene in the atmosphere at different regions of Iran for policy makers and scientists and may be a groundwork for field studies on benzene concentration estimation.

Multicriteria Optimization of the Catalytic Reforming Reactor Unit Using the Genetic Algorithm

The study is devoted to multicriteria optimization of the operation of the reactor unit intended for reforming of oil fractions. The optimization is based on the earlier developed mathematical model, which can take into account changes in the temperature and molar consumption of the reaction mixture during chemical transformations, the composition of the feedstock being processed, and the circulation quality and ratio of the hydrogen-containing gas. The following criteria are used in such optimization: octane number, yield of the target product (reformate), content of the sum of aromatic hydrocarbons, and content of benzene. The optimization was implemented using Pareto approximation with the genetic algorithm. Temperatures at the reactor inlets served as the control parameters. As a result of optimization, the sum content of aromatic hydrocarbons decreases from 56 to 45 wt.%, and the octane number measured by the research method (RON) decreases from 92.7 to 90.7 points. The three-criteria optimization is also considered; it provides a decrease in the benzene content from 4 to 3.08 wt.% with a decrease in RON from 92.7 to 91.8 points. In both cases, the decrease in the octane number is admissible, taking into account the fulfilled requirements to the limiting content of benzene and aromatic hydrocarbons in the reformate.

A Multi-Response Optimization for Isomerization of light Naphtha

Isomerization process is considered one of the main processes used to produce high octane rating gasoline with improved environmental conditions and less emissions. The main keys of performance in isomerization units are the product yield, paraffin isomerization number (PIN) and octane number (RON). In this article we present a multi-response optimization strategy for an industrial naphtha continuous isomerization-process that aims to maximize RON, PIN and yield. Data of 53-runs including feed compositions as well as operating conditions; reactor temperature, benzene content, liquid hour space velocity, feed PIN, hydrogen to hydrocarbon ratio, feed octane number, C7+ content, inlet reactor temperature and iC5/C5P ratio are collected from a refinery company over a period of two months to test the effect of each variable and their interaction over each response individually using analysis of variance (ANOVA). Model reduction is applied for the three models in order to exclude any insignificant data and improve the model’s accuracy. Finally, the optimum operating conditions for the process are selected using numerical optimization in Design Expert 11 by comparing with the real industrial data runs to give the maximum yield, PIN and RON which are 99.992, 122 and 86 respectively. Benzene content is selected to be 1.807 wt%, reactor temperature;143oC, LHSV; 0.882 h-1 , feed PIN; 64.611, H2 /HC; 0.07, feed RON; 74.408, C7+; 4.06 wt%, inlet reactor temperature; 116oC and iC5/C5P ratio 45.768.