دوماهنامه مهندسی شیمی ایران
پیاپی 18 (مهر و آبان 1384)

Environmental biotechnology has the intention of increasing sustainability of production process by employing biological systems. Although, the remediation field obtained a boost by novel development in the field of phytoremediation, more recently a transition of environmental biotechnology from remediation to manufacturing is taking place. The impact (production) of approximately 100* 10¬6 tone per annum of various plastic materials are the source of increasing problem. To overcome these problem three methods were studied: material recycling, thermal recycling and composting. In the recent studies, traditional plastics institute by biodegradable plastics. One of the bioplastics, microbial plastics, is biodegradable and has a special chemical structure. These bioplastics can employ in chemical, pharmaceutical and food industries.

Nano-fluids, which are suspensions of nano-sized particles in a fluid, have attracted interest in convective heat transfer as a heat transfer medium. In this paper, review of preparation of nano-fluids, probable mechanisms of heat transfer enhancement in nano-fluids, and sample applications of nano-fluids are presented. Nano-fluids showed a great potential for enhancing convective heat transfer.

The present paper relates to a spray able composition which can be used as a coating in construction materials and which contains a major amount of sulfur, which has been plasticized and reinforced with minerals.Compositions containing sulfur have been investigated for use as coatings, as sulfur-aggregate concretes, and as sulfur-asphalt road paving mixtures. For example, it has been proposed to use sulfur-polysulfide-glass fiber reinforced compositions for joining blocks for wall construction. It has also been proposed to use sulfur coatings for forming impervious layers in walls and generally for coating earthen tanks, drainage and irrigation canals, ponds, concrete structures, etc. According to the present paper a sulfur composite is containing sulfur, a plasticizer, mineral fillers, and a dispersing agent.In general, the sulfur composites are prepared by adding a plasticizer to molten sulfur, followed by the dispersing agent and finally the mineral fillers. For this purpose, sulfur is heated to a temperature above the melting point (i.e., above about 116 °C) but preferably in the range of about 140 – 160 °C. Then the plasticizer is added and mixed intimately with the molten sulfur. When a plasticizer is formed by "in situ" reaction of an additive compound, is allowed for reaction before the remainders of the components are added. It is then preferable to add the dispersing agent before any other ingredients because this helps in obtaining good dispersion in the plasticized sulfur. After all the ingredients have been added the composition is stirred to obtain a homogeneous blend.

The operation of the sour water stripper of Shiraz refinery was traced during several test runs. The exit flow rate of the stripper during normal operation was about 32 m3/hr from which 6 m3/hr was the result of condensation of direct injection of steam to the stripper. By performing some experiments on inlet and outlet streams to the degasing drum and stripper, simulating the process with HYSYS, and precise control of the stripping parameters, the quality of the exit water reached to the acceptable levels. The applied result of the project was reuse of treated sour water in desalter of the refinery.