No abstract

In this work, an artificial neural network-group contribution model is developed to predict the standard enthalpy of formation in the solid (crystal) state of pure compounds. Several classes of hydrocarbon compounds CH, oxygenated compounds CHO, nitrogen compounds CHN, and energetic compounds CHNO are investigated to propose a comprehensive and predictive model. The new model is developed and tested for 1222 organic compounds containing complex molecular structures. The performance of the new model has been compared with previous work and is shown to be far more accurate. The obtained results show an average absolute deviation of 9.33 kJ·mol −1 and a coefficient of determination of 0.9972 for the experimental values.

This study aims to determine the efficacy of using calcium hydroxide Ca(OH)2 in coagulation process to treat urban liquid effluent from wastewater purification plant. The response surface methodology was used. The effects and interactions between three key process parameters was enhanced applying Box-Behnken design. Factors studied were: coagulant dosage (g/L), coagulation speed (rpm), and coagulation time (min). The treatment efficiency was determined by the turbidity removal rate and the final pH of the treated wastewater. The statistical soundness of the generated model was determined using analysis of variance. The optimal model for determining the relationship between the variables is a second-order quadratic model (R2>98 %). The best turbidity reduction (91.3 %) was obtained using a 0.50 g/L Ca(OH)2 coagulant and 130.1 rpm for 5 minutes. Under these conditions, the ultimate pH of the effluent reached 8.

Hydrocarbons, aldehydes, sulfides, heavy metals, and other contaminants from petroleum treatment processes have been discovered in the oil and gas industry liquid discharge. Hydrocarbons primarily cause the pollution shared by all units. The purpose of this study is to assess the performance of the coagulation-flocculation process in the primary treatment stage for the removal of hydrocarbons and turbidity from the effluent of the Algerian oil refinery RA1/Z. Using 1 g/L of calcium hydroxide coagulant and operating at a stirring speed of 100 rpm for 3 minutes, an excellent elimination of 95.1 % and 90.4 %, respectively, of turbidity and hydrocarbons, was achieved.