Iranica Journal of Energy and Environment (IJEE)

265-274

Authors: Krityanand Kumar Mahatman, Neha Garg, Ranjeeta Chauhan, Anil Kumar

Xylanase (EC. 3.2.1.8) has been isolated from an alkalo-thermophilic bacteria, Bacillus halodurans strain KR-1 isolated from the soil near river bed at Indore. The bacteria secreted xylanase in the growth medium in the presence of xylan. The production of the enzyme was induced in the presence of glucose, mannose, lactose and maltose whereas presence of starch, cellulose and sucrose retarded in enzyme production. The presence of casein, peptone, sodium nitrate and potassium nitrate as nitrogen source in the growth medium resulted in more xylanase production, whereas presence of ammonium sulfate, ammonium nitrate and yeast extract resulted in lesser enzyme production. The enzyme has been partially purified using sodium sulfate fractionation, DEAE-cellulose and Sephadex G-200 chromatographies. The molecular weight of the enzyme has been found to be 45±02 kDa as determined by Sephadex G-200 chromatography as well as sodium dodecyl sulfate polyacrylamide gel electrophoresis. The enzyme protein is monomeric exhibiting maximum activity at pH 9.0. The optimum temperature for exhibiting maximum activity has been found to be 40oC. The metal ions viz. Mg2+ and Fe2+ when present in the enzyme assay medium stimulated the xylanase activity, whereas Hg2+, Co2+ and Mn2+ strongly inhibited the enzyme activity. The Km value for birchwood xylan was calculated to be 12.0 g/l.

280-286

Authors: Neeta Sharma, Seema Rana, Anunidhi Sharma

The densities, viscosities and ultrasonic velocities of binary mixtures of methanol with acetonitrile and dimethyl formamide have been determined at 298.15, 303.15, 308.15 and 313.15 K over the whole composition range. From the experimental data the values of compressibility (Ks), excess compressibility (Kse) and excess viscosity (ηe¬) have been calculated. The results are discussed and interpreted in terms of molecular package and specific interaction predominated by hydrogen bonding. The data at various temperatures also provide an opportunity to study the effect of temperature on the sign and magnitude of the deviation in viscosity and compressibility. Results show that excess properties are found to be either negative or positive depending on the molecular interactions and the nature of liquid mixtures.

293-298

Authors: S. H. Sengar, A.K. Kurchania

Dual purpose solar oven (DPSO) was designed and constructed. It observed that by using the new design of solar oven, both function of cooking and drying were possible for meeting the requirement of a family. The maximum stagnation temperature of 119°C and water temperature of 93.25°C were obtained in winter in DPSO while using as cooker. The calculated values of figure of merit F in DPSO was 0.119 and the time duration 1 for raising water temperature from 60 C to 90°C in hot box was 120 min. Cooking trials have also been conducted 0.5 kg of rice in 1 kg of water and 0.250 Kg of green gram split washed in one and half hrs in winter while it took about one hour in summer. The maximum temperature of 58 °C was recorded at 14:00 hrs of the day at level of tray no.2 when used as dryer. The time required to dry maize on different trays upto average moisture content 7.13 %( w.w.) for winter and 5.43 %( w.w.) for summer (w.w.)was 420 minute and 360 minute respectively. The total cost of solar oven was worked out to be Rs().2,715. Its pay back period varied between 1.3 to 1.86 years depending upon fuel it replaced.

305-314

Authors: Ritesh Joshi, Rambir Singh

Every year wildfires in Rajaji National Park, north-west India destroys more than 250 hectares of landscape encompassing tall grasslands and mixed forests. This is not only making a negative impact on wild species, but also causing a drastic impact on elephant’s seasonal movements. This study evaluated the impact of three fire seasons in 2007, 2008 and 2009 on the elephants of Chilla and Haridwar forest ranges. The 2008 forest fire burned 95 (0.64%) hectare of the Chilla forest followed by 2007 (75 hectare, 0.50%) and 2009 (60 hectare, 0.40%) whereas the 2007 fire burned 120 hectare (1.40%) of Haridwar forest followed by 2009 (105 hectare, 1.23%) and 2008 (95 hectare, 1.11%) fires. Scarcity of natural water during dry periods is another major factor which is affecting elephant’s movements within their home range. Chilla and Haridwar forests are currently facing water scarcity as far the elephant distribution is concerned, most of the perennial water sources have shrinked or remaining are on the verge of it, whereas before 2002 all of these water sources were fulfilled with tremendous water. Our review of available evidence suggests that wildfires and shrinkage of natural water sources have caused a catastrophic decline of free-ranging elephants from the Chilla and Haridwar forest ranges. All of these data support the importance of protecting the Rajaji National Park and its adjoining protected habitats as an important elephant range, linking different protected areas in north-west India.

321-325

Authors: K. Varunprasath, Nicholas A. Daniel

The study on some physico-chemical characteristics of River Bhavani at its source and Mettupalayam and Sirumugai has been calculated for the period of one year (July 2007 to June 2008). The sampling points were selected on the basis of their importance. For surface water determination of water quality index becomes essential and pre-requisite. Analysis of some physico-chemical characteristics like water temperature, colour, electrical conductivity, transparency, total suspended solids, total dissolved solids, pÇ, dissolved oxygen,BOD, total alkalinity; total hardness has been done during the investigation period. Increase in temperature, turbidity, pH, electrical conductivity, total solids, suspended solids, dissolved solids, BOD values were higher in Sirumugai station, whereas the increase in total hardness, bicarbonate values were higher in Mettupalayam due to the intensity of expulsion of contamination. The dissolved oxygen values higher in Pillur dam station owing to unpolluted water. The Bhavani river has been facing severe anthropogenic activities, mostly due to municipal sewage and industrial waste and dense population etc.

331-338

Authors: Meriem Azaiez, Ikram Zbali, Saber Ben Abdessalem

Textile cardiovascular prostheses are woven or knitted structures made generally from biocompatible polyester fibres. After production, they have to undergo special treatments before packaging such as compaction. This treatment is necessary to reduce porosity especially for knitted structures, but it can modify poly(ethylene terephthalate) (PET) polymer’s properties. We have studied the effect of chemical and thermal compaction process parameters on physical properties of PET with DSC and XRD techniques. The obtainedresults show changes of glass transition temperature according to compaction parameters. A multiple melting peaks thermograms were observed for untreated and most compacted samples indicating differences between crystallites sizes. The compaction treatment involves an increase of PET crystallites size because of molecular bonds rearrangement among the polymeric chains. With DRX, we have showed crystallites size increases for compacted samples when compared with untreated samples. This increase is particularly important in perpendicular direction to (010) crystallographic plane.

347-351

Authors: Nagaraj Naik, K.S. Jagadeesh, M.N. Noolvi

Four microorganisms isolated from samples of mangrove areas were found to be promising and significantly decolorized spent wash. Incidentally, they showed higher phenol degradation and COD reductionas well. The individual colorants imparting the color to spent wash were fractionated. Degradation of melanoidin and caramel was confirmed by UV and FTIR spectral analysis. Decrease in OD of melanoidin and caramel at their 8 max and appearance of new peaks and changes in functional groups of compounds in the IR spectra with respect to control suggest their degradation. K1 was the best melanoidin (77%) as well as caramel (54%) degrader followed by other three isolates (Ku3, Rtb2 and EB4).

359-366

Authors: Rashid Nizam, S. Mahdi, A. Rizvi, Ameer Azam

The electronic structure and the conductance of carbon nanotube based metal/semiconductor/metal intramolecular junctions are investigated numerically. The nature of electronic states at the interfaces and in the semiconductor section is analysed with the help of tight-binding method. The quantum conductance of the system is calculated in the logical regime and its variations with energy have been observed. These quantum conductances have been compared among the different carbon nanotubes and that have been correlated with the pentagon and heptagon that formed in the intramolecular junction.

170-175

Authors: T.S. Pathan, P.B. Thete, S.E. Shinde, D.L. Sonawane, Y.K. Khillare

The fishes, Rasbora daniconius were exposed to lethal concentration at 9.5% (LC50 of 96 hrs) for 96 hrs and sublethal concentrations [1.9 % (1/5) and 0.95 % (1/10) LC50 of 96hrs] of paper mill effluent, for 30 days to study the impacts on the histology of gill. Many pathological changes were observed in the gill lamellae such as bulging at the tip of primary lamellae, epithelial hypertrophy, Fusion, curling, reduction in secondary gill lamellae, disorganization and rupture in secondary lamellae, swelling in pillar, mucous, and chloride cells. Hemorrhage at the primary and secondary lamellae.

179-183

Authors: Joseph Selvin, Aseer Manilal, C. Rani, B. Sabarathnam, G. Seghal Kiran, Sujith Sugathan, Chippu Shakir

An extensive study on the prevalence of seromarkers (HBsAg and AFP) of hepatocellular carcinoma among two low socioeconomic groups of Karumanthurai tribes and Kanyakumari coastal population was carried out. The results obtained suggest that the mean HBsAg value of tribal was more than that of the coastal population. The mean AFP of elevated and normal cases was found to be invariably significant (P< 0.01) over the two areas. Coastal patients tended to be significantly older than the tribal patients (P < 0.005, Wilcoxon rank sum test). All two racial/geographic regions showed a preponderance of male patients but this tendency was significantly more marked (P < 0.05) in the tribal group than in the coastal sample. Liquor habit and lack of personal hygienic practices were associated with the prevalence of HBsAg and AFP in both the areas. Surprisingly a positive association has been found between the consumption of marine foods and reduced risk of HCC. Thus the reduced risk of HCC among coastal population can probably be due to the development of immunity against HBV due to the dietary pattern of marine food consumption by coastal population.

192-195

Authors: Ali Aberoumand

In addition to meeting nutrient intake levels, greater consumption of fruits and vegetables is associated with reduced risk of cardiovascular disease, stroke, and cancers. The proximate composition and mineral constituents of Chlorophytum comocum root tubers were evaluated. The root tubers contained a ashes: 10.38%,crude protein: 4.54%, crude lipid: 2.00%, crude fiber: 17.24%, and carbohydrates: 65.84%. The leaves and stem also have high energy value (299.52kcal/100g)dry weight where as Alocacia indica stem contained a ashes: 9.1%,crude protein: 5.44%, crude lipid: 3.25%, crude fiber: 22.9%, and carbohydrates: 59.31%. The stem also have high energy value (288.25kcal/100g)dry weight Comparing the root tubers mineral contents with recommended dietary allowances (RDA), the results indicated that Chlorophytum comocum root tubers could be a good supplement for some nutrients such as calcium, fibre and carbohydrates where as the results indicated that Alocacia indica stem could be a good supplement for some nutrients such as Fibre, Potassium, Zinc, lipid, and Carbohydrates. The root tubers and the stem could be promoted as a carbohydrate supplement for cereal-based diets in poor rural communities, while its high potassium content could be utilized for the management of hypertension and other cardiovascular conditions.

200-204

Authors: Atul R. Dange, S.K.Thakare

Pigeon pea or tur (Cajanus cajan L. Mills.) is one of the important pulse crops of India and ranks second to chickpea in area and production. Traditionally the harvesting of pigeon pea is done manually by sickle, which demands considerable amount of labour, drudgery, time and cost to harvest, which reflects on total production cost of the crop. In view of this a tractor operated front mounted pigeon pea stem cutter was developed and being front mounted implement it facilitated better visibility and control to operator. The power was transmitted from pto to gear box. Arrangement of hydraulic cylinder and hydraulic motor was provided on the equipment to facilitate the height of cut and to rotate the conveyer belt. During comparative performance evaluation of developed equipment, the average cutting efficiency and field capacity was found 96.30 % and 0.176 ha/hr respectively. There was increase in fuel consumption and plant damage with increase in speed of operation. The average operation cost of newly developed tractor operated front mounted pigeon pea stem cutter was 64.71% less as compared with manual harvesting of pigeon pea crop. The time saved was almost 1/3rd to that of manual harvesting.

211-221

Authors: G. Venkata Subbaiah, Dr. K. Raja Gopal, Syed Altaf Hussain

History has seen fuel innovations being driven majorly by transportation needs rather than the overall need to revolutionize the energy needs of the society. Biofuels such as biodiesel and bioethanol are now receiving the impetus required for becoming a fuel source for the future. One of the ways to reduce the dependence on fossil diesel is the blending of bioethanol with conventional diesel. However, an emulsifier or a co-solvent is required to stabilize the blend. The ricebran oil biodiesel offers an alternative application as an emulsifier for diesel-ethanol blends to form diesel-biodiesel-ethanol blends. In the present study the rice bran oil biodiesel was used in different ways such as pure biodiesel, blending with diesel and diesel- ethanol blends. The performance and emission characteristics of a direct injection (DI) diesel engine when fuelled with conventional diesel fuel, pure biodiesel, a blend of diesel and biodiesel and three blends of diesel-biodiesel-ethanol were studied over the entire range of load on the engine. The experimental results showed that the highest brake thermal efficiency was observed with 30% ethanol in diesel-biodiesel-ethanol blends. The exhaust gas temperature and sound reduced with the increase of ethanol percentage in diesel-biodiesel-ethanol blends. The Carbon monoxide, smoke, exhaust gas temperature and sound reduced with the increase of ethanol percentage in diesel-biodiesel-ethanol blends. The minimum values of Carbon monoxides, smoke, exhaust gas temperature and sound intensity were observed with the blend BE30 and were respectively 41.23%, 14.5%, 0.57% and 11.53% lower than that of the diesel fuel. The Oxides of nitrogen and carbon dioxide emissions increased with the increased percentage of ethanol in diesel-biodiesel-ethanol blends. The hydrocarbon emissions increased with ethanol but lower than that of the diesel fuel by a maximum of 35.35% with 10% ethanol in diesel-biodiesel-ethanol blend. The blending of 20% biodiesel into diesel-ethanol blends allowed higher percentage (30%) of ethanol mixing with diesel, increased the brake thermal efficiency and reduced the carbon monoxide, sound, hydrocarbons and smoke than that of the diesel fuel. So the rice bran oil biodiesel can be used as an emulsifier to mix higher percentage of ethanol with fossil diesel to improve the performance and reduce the emissions of a diesel engine.

228-233

Authors: Aliakbar Hedayati, Alireza Safahieh, Ahmad Savari, Jasem Ghofle Marammazi

Toxicity tests allow the determination of pollution effects, providing direct evidence of the biological responses of marine organisms to contaminants. Fifty four yellow fine sea bream all immature male in same size (120 g final body weight average) were obtained from Mahshahr creeks with hooks in a Upon capture. In laboratory Fish maintained in a seawater re-circulatory system (300-L tanks) equipped with physical/biological filters and with aeration. All samples were acclimated for one weeks in a 15 aerated fiberglass tank containing 46 ppt saltwater maintained at 25 C under a constant 12:12 L:D photoperiod. Acclimatized Fish were fed daily with a live feed (fresh shrimp) and daily we check water quality and water parameters. Hg2+ tested concentrations were 20, 50, 100, 200, 500, 1000, 2000, 5000 and10000 µg/l, Groups of six male yellow fine sea bream (120 g) were exposed for 96 h to each of the Range Finding Test for LC50, in fiberglass tank equipped with aeration with 100 l of test medium. The control group was exposed to filtered sea water in similar conditions. Test medium was not renewed during the assay and no food was provided to the animals. Values of pH, Temperature, and salinity were measured at time 0, 24, 48, 72 and 96 h. At the end of the bioassay, Range values were determined as 500-1000 µg/l (fifty percent of mortality between 500 and 1000). Range Finding Test values indicated that mercury is more toxic to A. latus. Range obtained in the present study compare with corresponding values that have been published in the literature for other species of fish, show different Range of mercury in different species and even different time, but what is important, lower value of Range Finding Test for A. latus compare with most species and confirm sensitively of A. latus to low mercury doses.

246-254

Authors: E.K. Ajani, S.O. Ayoola

The piscicidal quality of water extracts of Adenia cissampeloides leaves on Tilapia (Sarotherodon galilaeus) juveniles was investigated in a static renewal bioassay to determine the median lethal concentration(LC ) at 96hour of exposure. Five graded concentrations of 800, 600, 400, 200 and 100 mg/litre of aqueous 50 solution of A. cissampeloides and a control 0 mg/10L were applied to S. galilaeus fingerlings in plastic tanks. The 96h LC of aqueous extract of A. cissampeloides to S. galilaeus under laboratory condition was 317mg/l. 50 Behavioural changes such as erratic swimming, loss of reflex, hyper ventilation, increased surfacing frequency and jerky movements were observed prior to death. Histopathological changes in the liver of S. galilaeus juveniles observed are severe widespread vacuolar degeneration and necrosis, hepatocytes, hyperplasia and presence of large numbers of megalocytes. In the gills, there were denudation of gill filaments, swelling of chondrocytes and rarefication of cartilage within gill filament. These damages became severe with increasing concentration of the plant extracts.

81-92

Authors: Md. Ashiqur Rahman, Dhia Al Bakri

The Buriganga river system is located in the southern part of the north central region of Bangladesh, passing through west and south of Dhaka, the capital of Bangladesh. The river receives wastewater from numerous numbers of sources along its way, which are discharged as industrial effluents, municipal sewage, household wastes, clinical wastes and oils. The purpose of this study is to investigate into the impact of this wastewater on the river water and thus to provide an updated report on the state of water quality of the river Buriganga. The water samples were collected in year 2008-09 during both dry and wet seasons from different points along the river and analysed for various physiochemical quality parameters, which includes: temperature, pH, EC, DO, BOD , COD, PO -P, NH -N, Pb and Cr. The mean values for the parameters in both dry and wet 5 4 3 seasons were compared with the surface water quality standards as set by the Department of Environment (DOE) in Bangladesh. The water quality test results have also been summarised and presented through box and whisker plots.

100-105

Authors: Mirtaghi Mirmohammadi, M. Hakimi, A. Ahmad, M. Mohammadyan, K. Kamel

Diisocyanates are used as a initial chemical material in different factories such as surface coatings, polyurethane foams, adhesives, resins, elastomers, binders and sealants. In the polyurethane workplace there are aerosols of diisocyanates which has important to effect on workers. They can also be exposed to partial reaction of isocyanate-containing intermediates formed during polyurethane production. The main objective of this study pointed on assessment of exposure risk factors with MDI in the workplace, determination of MDI concentration and biomonitoring of MDA in polyurethane industries. NISOH (National Institute for Occupational Safety and Health) 5522 sampling and analysis method was used by midget impinger contained dimethyl sulfoxide with tryptamine. HPLC (High Performance Liquid Chromatography) was employed for air sampling analysis and GC (Gas Chromatography) for urine analysis. Getting personality data was carried out by Health Surveillance Questionnaire and multiple linear regression models with ANOVA test was used for the statistical analysis. The result of study showed that there was a diisocyanate pollution (MDI > 96.6μg/m³) and it have seen in the workers' urine. A new approach to assess isocyanate pollution in the workplace is risk factor assessment simultaneously with indoor air pollution and biological monitoring.

124-131

Authors: R. Adjia1, W.M.L Fezeu, J-B. Tchatchueng, S. Sorho, M.B. Ngassoum

Heavy metal concentrations were estimated in five leafy vegetables (Solanum nigrum, Brassica oleraceae, Lactuca sativa, Amaranthus hybridus and Corchorus olitorius) from urban and periurban sites in Ngaoundere (Cameroon) using an Atomic Absorption Spectrophotometer (AAS). Vegetable samples were collected at the two stages of maturity: stage I (60 days) and stage II (90 days) for analysis. The results showed that the concentrations of heavy metals in all vegetables were greater in urban site than in periurban site. The highest concentrations of Fe (673.92 mg/kg DW), Cu (10.42 mg/kg), Cd (1.70 mg/kg DW), and Pb (31.75 mg/kg DW) were recorded in Lactuca sativa, Zn (94.60 mg/kg DW) in Solanum nigrum, and Ni (16.91 mg/kg DW) in Corchorus olitorius. The concentrations of Cu, and Pb were greater in roots than in aerial parts, while Fe, Cd, Ni and Zn concentrations were greater in aerial parts than in roots. Some of the concentrations of Ni, Zn and Pb in crops reached the critical level for plant growth. In general, the results indicated that the consumption of leafy vegetables harvested at the stage II potentially provides the greatest amount of heavy metals. The transportation index (Ti) decreased in vegetables harvested at the stage II for Fe, Cu, Cd and Zn but slightly increased for Ni and Pb, suggesting that heavy metal transportation from roots to aerial parts depends on the plant phenology and metal species. In all farms and at the two stages of maturity, the lead concentrations in all vegetables were more than the FAO/WHO maximum recommended level in leafy vegetable for human consumption. Moreover, all vegetables had some Cd concentrations that were higher than limits set by FAO/WHO. So, they are not suitable for human consumption.

137-143

Authors: G.D. Najafpour, A.A. Ghoeyshi, M. Mohammadi, Sharif Hussein Sharif Zein

Methylene blue (MB) adsorption from aqueous phase was investigated. Pretreated walnut shell, as adsorbent was used. Experiments were conducted in a batch system for determination of sorption equilibria and then the data were incorporated in a packed column for the removal of MB from synthetic wastewater. The generated wastewater was contained 4 mg/l of MB. The wastewater was pumped through the column with flow rate of 18 ml/min and the effluent samples were collected. The effect of influent MB concentration (4 and 8 mg/l) and pH (5, 7 and 9) of wastewater on removal efficiency of dye were investigated. Langmuir adsorption isotherm model was implemented to interpret the experimental data. The obtained results revealed that the sorption data were well described by Langmuir model at pH value of 9. At contact time of 300 min, maximum equilibrium adsorption of MB uptake 6.7mg/g adsorbent was achieved.

160-164

Authors: V. Lalitha, K.A. Raveesha, B. Kiran

Aqueous and Solvent extracts of leaves of S. torvum viz., Petroleum ether, Benzene, Chloroform, Methanol and Ethanol were tested in vitro for antimicrobial activity following the procedures of poisoned food technique and cup diffusion method against some important seed borne pathogens of paddy viz, Pyricularia oryzae, Alternaria alternata, Bipolaris oryzae, Tricoconis padwickii, Dreschlera tetramera, D. halodes, Curvularia lunata, F. oxysporum, F. moniliformae, F. solani and Xanthomonas oryzae. Aqueous extracts of leaves (at 25% concentration) showed 100, 47.44, 60.47, 71.50, 56.11, 63.33, 78.62, 66.66, 47.44 and 46.27% inhibition of the test pathogens respectively. Highly significant antifungal activity was observed in Methanolic and ethanolic extract. The percentage inhibition of the test pathogenic fungi in Methanolic extract was 100% (P.oryzae), 74.42 (A. alternata), 65.68 (B oryzae), 87.62 (C .lunata), 100% (T. padwickii), 63.33 (D.halodes), 60.31 D. (tetramera), 76.01 (F.moniliformae), 59.21 (F. oxysporum), 43.91% (F.solani) and zone of inhibition of Xanthomonas campestris pv oryzae was 18 and 30mm in Methanol and ethanol extract.

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.