A novel modeling approach to optimize oxygen–steam ratios in coal gasification process

Coal gasification operation appears to be an essential element in the advanced energy systems, where the reaction between oxygen, steam and coal results in production of syngas (e.g., a mixture of carbon monoxide and hydrogen) under elevated pressure and temperature conditions. An efficient design for gasification process is expected if proper oxygen/steam rations are selected such that a thermal balance is established between the exothermic and endothermic reactions, leading to yield maximization of desired products in most cases. In this article, a rigorous modeling approach using support vector machine (SVM) algorithm is developed to estimate optimum oxygen–steam ratios required to balance the released heat and heat requirement in coal gasification process. An acceptable match between modeling outputs and real data is noticed so that the average absolute error is lower than 1.0%

Evaluation of heavy metals in the tissues of different species of shrimps collected from coastal waters of Bushehr, Persian Gulf

Background: The occumulation of heavy metals which are as the results of industrial, urban and agricultural sewages are usually resistant to chemical dissociation. They can easily contaminate aquatic animals especially shrimps which are one of the food chains of humans. The aim of this study was to evaluate the concentration of heavy metals in the tissues of different types of shrimps (wild and farmed) in the sea waters of province of Bushehr (Persian Gulf). Material and Methods: Wild shrimps from different areas of the province and also three types of farmed shrimps including Ferropenaeus, penaeus semisulcatus and Litopenaeusvannamei were caught and collected. Then cleaned, washed, dried and made into powder and then made into ash in a furnace at 550 °C. Heavy metals including Pb, Cd, Hg, Cu, and Zn were measured by atomic absorption flame photometry. Results: The mean values of the concentration of the heavy metals including Pb, Cd, Zn, and Cu present in the wild shrimps were, 2.86, 9.53, 0.45, 1.36 ppm respectively. The amount of Hg found to be 2.8 ppb. Also the mean values of the concentration of the heavy metals in the farmed shrimps were measured as 3, 9.8, 0.42 and 1.37 ppm respectively and the amount of Hg was 2.7 ppb. There was no difference between the amount of heavy metals estimated in the tissues from wild shrimps and the farmed one. Conclusion: The results of this investigation showed that the concentration of heavy metals including Zn,Cu and Hg in both types of the shrimps were less than the amounts reported by WHO and so not risky for health. However the concentration of Pb and Cd in both types were more than the recommended consumption limit for the humans, and they can be considered as risk factors for many diseases. This suggests that attempts should be taken by the responsible authorities to prevent the contamination of sea waters