A SCREENING OF THE HYDROGEN SULFIDE LEVELS IN PLOIESTI CITY, ROMANIA

Oil refineries and petrochemical facilities contribute to the pollution of the environment either air, water, or soil releasing hazardous and toxic air pollutants into the atmosphere. These include nitrogen oxides (NOx), carbon monoxide (CO), hydrogen sulfide (H2S), sulfur dioxide (SO2), and particulate matter (PM), affecting both environment and human health. In the range of air pollutants, hydrogen sulfide is less monitored and reported despite its importance in determining adverse effects. Background H2S concentrations in air were found to range commonly from 0.11 ppb to 0.33 ppb. The concentrations in urban areas can reach 1 ppb (~1.4 g m-3) up to more than 90 ppb (~125 g m-3) near sources of H2S emissions. In Romania, the standard for the air in protected areas for the hydrogen sulfide pollutant provides an admissible concentration, over a maximum interval of 30 minutes, of 15 µg/m³. Everything that exceeds this value is considered harmful to human health. The statistics for the H2S time series recorded in Ploiești City by the mobile laboratory of the Environmental Protection Agency Prahova between 2019 and 2021 with a sampling rate of 30 minutes showed that the mean ranged between 1.51 and 3.74 µg/m³, while the maximum reached 59.36 µg/m³ in the east of Ploiești in 2019. Overall, the highest variance occurred in the East and North parts due to the presence of the concentration peaks. Hydrogen sulfide must be considered on the public health agenda, both from the occupational perspective and for the ambient concentrations near significant H2S sources and in background urban areas. The monitoring infrastructure needs to be improved to allow continuous surveillance to ensure reliable databases that support research regarding the health effects of H2S across the concentrations occurring in the urban environment

Acidity Influence of Catalysts on the Process Selectivity for the Hydrogenation of Methyl Oleate

The hydrogenation of methyl oleate was conducted on two catalysts based on Ru, Ru-Sn/γ-Al 2 O 3 respectively Ru-Sn-Ba/γ-Al 2 O 3 . The catalysts were prepared by sequential impregnation. The distribution of the acid strength of the prepared catalysts was determined by thermic desorption of diethyl amine in the temperature range from 20 to 600°C. Experiments were carried out on a laboratory echipament using a fixed bed catalytic reactor at a temperature of 275°C, pressure of 100 atm with a methyl oleate volume flow rate (VHSV) of 0.15h -1 and molar ratio hydrogen/ methyl oleate of 10/1. The main compounds identified were saturated and unsaturated fatty alcohols and saturated hydrocarbons. Ru-Sn catalyst activity was superior to that of Ru-SnBa, probably due to an optimal distribution of the acid strength of this catalyst