Iranica Journal of Energy and Environment (IJEE)

1-8

Authors: M. Pazouki, S.M. Rauf Hosseini, M. Ranjbar

Kaolin known as mineral clay possesses special feature has extensive industrial usage. One of the distinct criteria of this substance is its white color. There are extensive resources of kaolin in Iran which unfortunately, due to the existence of iron oxides does not have transparent properties. In this study biological dissolution of iron oxide by Aspergillus niger NCIM548 was conducted in order to remove kaolin impurities. As a result, a model was developed to predict the percentage of iron removal using A. niger. Bioleaching of iron oxide at optimum condition resulted 2.2 percent of total iron removal. The obtained results were promising for continuous process. There was possibility of increasing iron oxide removal at optimum operating condition with use of related fungi. Further studies may be required to enhance the desired condition for maximum iron oxide removal from kaolin.

17-24

Authors: N. Shahbahrami, A.R. Hajbari, A.J. Novinruzer

Synthesis of nickel nanoparticles in various sizes in self reduction process of NiCl2, in an aqueous environment of alcohol and hydrazine in the presence of various amounts of sodium hydroxide catalyst has been studied. The results indicate that NaOH and hydrazine catalyst concentrations play major role in the synthesis of nanoparticles. Several samples of Ni-anocatalyst particles in single phase of 0.2 M NaOH and pH value of 12, 12.5, 13 and 13.5 were synthesis. The obtaimned results were confirmed by XRD and FTIR spectra analysis. Phase structure and morphology of nanoparticles with SEM and XRD analysis were identified. Crystallography on several synthesized samples showed that nanparticles had FCC structure with the category layers of (111) (200) and (222) with particle size ranged 6.5-20 nm at room temperature and pH of 12-13.5. Network coefficient increased by reduction of nanoparticles size and particle size was enhanced with an increase in the solution temperature ranged 25 °C to 125°C. At high pH, atomic absorption analysis confirmed enhances of the produced Ni nanoparticle concentrations.

33-42

Authors: B. Raei, F. Shahraki, M. Khorrami, A. Ghadi

There are several alternatives to enhance the efficiency of energy usage and to decrease energy losses. Pinch technology is the best method of approach to enhance energy efficiency. Heat exchangers network (HEN) of refrigeration unit of ammonia production process was analyzed to use pinch technology to decrease energy usage. The obtained results showed that pinch technology was unsuccessful for the shaft work targeting capabilities. In contrast, it is posed that for optimization of such systems, one should use the combined pinch and exergy analysis (CPEA) method. In this analysis CPEA method was used in the system. It was observed that the refrigeration system use cold streams for cooling the hot streams. Therefore, retrofitting the refrigeration cycle without changing the main process is impossible. Some suggestions were made for improving the refrigeration system, such as the use of economizer after cooler, multistage cycle and removal of the 111-FFD3 stream. It was also observed that the exchanger 128-E act as an intercooler and the flashed 110-F, 111-F and 112-F act as an economizer. In addition, ammonia refrigerant was used at three different temperatures of -33,-7 and 13.5 ˚C. Also, eliminated the 111-FFD3 stream bring about 2% reduction in exergy loss.

51-58

Authors: M. Hakimi, A. Ahamd, O. Kader, M. Mohammadian, S.B. Mirashrafi

Isocyanates are known as highly reactive chemicals. Isocyanates/diisocyanates are often used as raw materials in production of polyurethane. The results of indoor air monitoring in all of the five polyurethane factories (n= 100) showed that all HDI concentration values were considered at high contaminated air, in comparison with exposure limit of 35μg/m3. The HDI concentration ranged from 62.24 to 92.7 μg/m3 with a mean HDI concentration of 78.8μg/m3. It was also shown that urinary HDA is detectable following HDI exposure. Urinary HDA concentration of the workers was found to be linearly related to HDI concentration of the air in the factories as correlated. The HDI work-related disease risk assessment of the present study showed that two personal and work condition variables were correlated with symptoms of HDI work-related disease in the polyurethane factories (workers’ weight and HDI pollution) (n= 350). A multiple linear regression analysis was performed to evaluate individual factors for developing asthma induced by diisocyanates. Two factors were statistically related to risk of work-related disease of diisocyanate at the 0.05 significance level. These were: (a) weight of exposed workers, (b) HDI pollution. None of them had experienced previous incidents of exposure to diisocyanates. This study has shown that air monitoring together with biological monitoring and also risk factors can be used to estimate the HDI pollution situation as well as the exposure to workers of polyurethane factories.

65-72

Authors: S.J. Safdari, A. Haghighiasl, R. Lak

In this paper, computer software for the application of models was extensively discussed. Initially, plug flow extraction model as ideal system were applied and then mix model whit forward mixing for two systems water/acetone/toluene and water/acetone/butyl acetate with high and medium surface tension were applied. Mass transfer direction was from dispersion to continuous phases. The transferring compound in the above systems was water and acetone respectively. Use of mix model along with Handlos-Baron resulted desired and optimum calculation of the sieve-tray column height.