A Heat Exchanger Reactor Equipped with Membranes to Produce Dimethyl Ether from Syngas and Methyl Formate and Hydrogen from Methanol

The energy crisis of the century is a motivation to present processes with higher energy efficiency for production of clean and renewable resources of energy. Hence, a catalytic heat exchanger reactor for production of dimethyl ether (DME) from syngas, and hydrogen and methyl formate (MF) from methanol is investigated in the present study. The proposed configuration is equipped with two different membranes for in-situ separation of products. Syngas is converted to DME through an exothermic reaction and it supplies a part of required energy for the methanol dehydrogenation reaction. Produced water in the exothermic side and produced hydrogen in the endothermic side are separated by using appropriate perm-selective membranes. In-situ separation of products makes the equilibrium reactions proceed toward higher conversion of reactants. A mathematical model based on reasonable assumptions is developed to evaluate molar and thermal behavior of the configuration. Performance of the system is aimed to enhance by obtaining optimum operating conditions. In this regard, Genetic Algorithm is applied. Performance of the heat exchanger double membrane reactor working under optimum conditions (OTMHR) is compared with a heat exchanger reactor without membrane (THR). OTMHR promotes methanol conversion to MF to %87.2, carbon monoxide conversion to %95.8 and hydrogen conversion to %64.6

Mutual diffusion in concentrated liquid solutions: A new model based on cluster theory

In dilute solutions, diffusion is dominated by motion of single molecules. Conversely, in non-ideal concentrated solutions, mass transfer by diffusion can be heavily influenced by molecular clustering. Cluster theory in concentrated solutions can be approached using the Cussler model, which has been used to explain experimental mutual diffusion data in highly concentrated solutions. In this work, using the Cussler model and the critical point theory as a starting point, a new model for predictions of mutual diffusion coefficients in binary mixtures over the whole composition range was developed. The model is based on modifications of the concentration correlation function and explains well the experimental mutual diffusion data and their dependence on composition and activity coefficients. The model does not require any knowledge of intra-diffusion coefficients and can be used to predict mutual diffusion coefficients over the whole composition range

Mutual diffusion in concentrated liquid solutions: A new model based on cluster theory

In dilute solutions, diffusion is dominated by motion of single molecules. Conversely, in non-ideal concentrated solutions, mass transfer by diffusion can be heavily influenced by molecular clustering. Cluster theory in concentrated solutions can be approached using the Cussler model, which has been used to explain experimental mutual diffusion data in highly concentrated solutions. In this work, using the Cussler model and the critical point theory as a starting point, a new model for predictions of mutual diffusion coefficients in binary mixtures over the whole composition range was developed. The model is based on modifications of the concentration correlation function and explains well the experimental mutual diffusion data and their dependence on composition and activity coefficients. The model does not require any knowledge of intra-diffusion coefficients and can be used to predict mutual diffusion coefficients over the whole composition range

A survey about existence currency of warm water fish in northern Alborz

Aquaculture is the most important part of Fisheries Organization duties in Iran. During several planning and developing programs, aquaculture productions had a considerable growth. Due to good potential, these productions were higher than the planed one. The North Alborz regions were investigated by four groups of experts. The regions which investigated were including 3 important provinces (e.g. Guilan, Mazandaran and Golestan). The area where investigated was 940 km along with coastal zone of Caspian Sea or 58678 km2 in total. Around 27% of aquaculture production came from this region. However, subdivision of fisheries can play important role in the economics in the region. The fisheries sub-sector has an important role in the economy of the region, and despite the great potential for agriculture and tourist industries in the North Alborz, there is a significant role in the prosperity of the fisheries activities. In the present study shows that Mazandaran and Guilan provinces has more potential in reservoirs and aquaculture production when compared with other provinces. Productions in Mazandaran either in reservoirs were less than Guilan province. Due to lee in reservoirs, Mazandaran had less investment when compared with Guilan province. The figures show that carrying capacity of aquaculture production for 3 provinces (Mazandaran, Guilan and Golestan) was higher than other provinces in the entire country. Due to, large land base, less investment, more interesting of farmers, no needs of complicated technology, farmer would be able to develop reservoirs as consequences to enhance productions. However, developing reservoirs and supporting of it's; can increase the contribution of warm water species in inland water