Nashrieh Shimi va Mohandesi Shimi Iran
Year:2007 | Volume:26 | Issue:2|Papers Count:15

Waste printed or laser printed paper with considering the ink size and type can be processed through the floatation, cleaning, and centrifugal unit to produce the drinking pulp for different paper industries. The ink size 100-400 micron has caused some difficulties in the production of deinking pulp within the limited existing deinking factories. In this experimental investigation the floatation method was used to deink the laser or printed paper with industrial and environmental aspect. The effect of various chemical material in the process on the effluent COD value, optimum ratio of the chemical material / dry paper weight, to obtain 80 % drinking and the effluent less than 1200 mg COD/l through a single stage floatation, is determined. The important parameters such as paper dryness percentage, air flow rate, aeration time, contact mixing time, ink particle size, air bubble size, and column dimensions are affecting the deinking efficiency. The effectiveness of each parameter under similar experimental condition is individually evaluated. The result of considering the floatation process in different experimental and industrial reactors showed that, the air distribution and air bubble size have the most affect on the increasing the deinking efficiency and optimizing the process. The result of analysis also showed that, under optimized condition 95 percent deinking is obtainable. According to the definition of kinetics constant of discussed experimental model , K 1 and K2 , If the technical aspect of drinking process are controlled inorder that K1, K2 are increased and decreased respectively, could increase the deinking efficiency.

Antibiotic production is a key area in biotechnology. To enhance the productivity and improve the economics, much attention has been paid on the improvement of the factors employed in the antibiotic production. Neomycin is an important aminoglycoside antibiotic used widely in pharmaceutical preparations. In this project, Neomycin production by Streptomyces fradiae was studied. Effective factors include: the composition of culture (starch media due to high polysaccharide carbon resource was selected), optimized pH of 7, temperature of 30°C shaking conditions was selected 150 rpm for 72 hr in electrical shaker or 400 rpm with 0.5 VVM air flux for 144 hr in 5 lit fermentor, the optimized production was 3760 mg/lit. Statistic Taguchi method was employed to optimize the production conditions. Results show that the media composition (soybean meal; MgSO4.7H2O; and starch) and pH were the most effective factors in production of Neomycin antibiotic.

Sulfur containing compounds of oil cuts cause air pollution, corrosion of metallic equipments and refinery catalysts poisoning, so using Hydrodesulfurization (HDS) catalysts and reducing sulfur content of oil cuts is critical. These catalysts generally contain a uniform monolayer dispersion of VIB group metal oxides such as molybdenum oxide and VIII group metal oxides such as cobalt oxide on a carrier preferably g-alumina. In this work successive dry impregnation of g-alumina by ammonium heptamolybdate and cobalt nitrate solutions was used to prepare HDS catalyst samples and then effect of impregnation solution pH. Mo and Co solution concentration, drying rate and feed flow rate on the Hydrodesulfurization performance was investigated. The samples were evaluated via scanning electron microscopy, porosimetery and reactor tests. The catalyst sample JDS-C5 shows the ability of reducing sulfur content of the feed from 1200 ppm to less than 1 ppm in the refinery HDS unit operation conditions (T=290 °C and P=15 bar).

Dyes can be derived from nature through various sources such as plants, flowers, seeds, barks, and roots. In this work, wool fabrics dyed with natural dyes extracted from the tea. Three different mordants were used in the experiments, potassium dichromate, copper sulphate and aluminum sulphate. The dyeing was carried out with mordant by using pre-mordanting method. Three properties of the finished samples such as wash fastness, rubbing fastness and dye color were evaluated. The latter was evaluated by using spectrophotometer color matching system. Various colors have been produced by using different mordants. The wash and rubbing fastness of the samples dyed with aqueous extract of tea were found to be good to excellent.

MTBE has great tendency to be absorbed by water and spreads in water resource. The possibility of presence and accumulation of MTBE in different parts of underground water resources in Tehran is studied. On this basis, 100 points (water wells) was carefully selected and were tested for MTBE content by the headspace solvent micro extraction (HSME) method. According to world standard, the maximum allowable MTBE content in water is 11-13 ppb while the high values up to 18 ppb were found in some of samples. Our results indicate that 2 percent of points are higher than maximum allowable, 7 percent of points are between 5-13 ppb and 91 percent are lower than 5 ppb. The effect of distance to petrol stations and storage tanks as well as the slope of the land and the direction of underground water flow were studies on concentration of MTBE in water samples. Results clearly showed the higher concentration of MTBE in the samples taken from the water wells closer to petrol stations and the wells on the same direction of underground water flow. Diffusion model of MTBE in underground water is presented.

In this study, production of black pigments for glass glazing was undertaken by using Cr, Mn, Fe, Ni, Cu and Co elements. After calcination at different temperatures (1200-1350 °C), the synthesized pigment was milled and sieved. The resulting pigment were characterized by using XRD, PSA, and STA. Different amounts of pigment (5-10 wt.%) was added to a transparent glaze and applied on a cleaned glass and then fired at 650 °C. The glazed samples were analyzed by UV-vis. spectrophotometer. The results showed that black pigment particles containing Cr, Fe, Co, Cu and Ni synthesized at 1350 °C give an appropriate black color to the final glaze.

A thermodynamic consistent model was developed for representing vapor-liquid equilibria in acid gases (H2S, CO2)-alkanolamine-water systems. The model accounts for both chemical and phase equilibria in liquid and gas phases, respectively. The activity coefficient of species was calculated using Pitzer-Debye-Huckel theory for long range interactions and UNIQUAC-NRF model with ion-pair approach for short range interactions. The energy interaction parameters of UNIQUAC-NRF were obtained for MDEA+H2O+CO2 and MDEA+H2O+H2S systems. The results of the model are in very good agreement with the experiment.

In this research effect of various clarifier materials on pomegranate juice quality were studied. Pomegranate juice was analyzed and its effective constitutes in this process were determined and important factors in clarification procedure were evaluated. Pectinas enzyme was used for pectin elimination and optimized consumption amount, temperature and time were obtained as 110 ppm, 50 °C, 60 min. respectively. Clarifying materials such as Gelatin (70 g/ton), Kieselsol 15 % (250 ml/ton) and Bentonite (250 g/ton) were used and in each case optimum condition and their advantages have studied. Also, for the first time PVPP (polyvinylpolypyrrolidone) was applied to solve secondary hazes problems and to produce stable clarified juice whose satisfying results have reported. Its consumption amount was determined as 80 g/100 lit.

Zinc oxide and titanium-strontium oxide were chosen for the present study because of the entire thermodynamically stable semiconductor in contact with aqueous solution, and its bulk properties (Band structure, nobilities impurity ionization energies, etc). Differential capacitance measurements of single crystal semiconductor interface and the aqueous solution K2SO4 and KCl in different pH enables us to measure flat band potential which carries the feature many semiconductor properties. Plotting Mott-Schottky curve based on the results obtained by measuring electrical capacity of ZnO electrode in contact with pH=2 solution led to a slope of 196.92 mF -2 Cm4 V-1, which corresponds with electron density of CD+ =4.21×1016 Cm-3. In the case of semiconductor SrTiO3 in contact with aqueous solution pH=2 concentration of donner was calculated CD+=1.273×1016 Cm-3. In contact with the solution pH=12 the concentration of donner is calculated as CD+=1.18×1016 cm-3. Measuring electrical interface capacity of semiconductors n types, SrTiO3 and ZnO in contact with different electrolyte solutions indicates that concentration of the donner CD+ depends on pH and that it has a linear change as with EFb if Dj=0.

Gas injection is an common EOR method for increasing oil recovery factor. Since the injection gas for such gas injection project is easily available, for guarantee the economic feasibility of such a plan. In this study, the performance of gas injection into one of the Iranian reservoirs is investigated. Three sets of core flood experiments were conducted. Each run was conducted at different composition and injection pressure with respect to others. The results of experiments revealed the fact that the recovery efficiency depends strongly on the injection pressure. It should also be noted that gas enrichment using components leading miscibility could increase the recovery. The optimum enrichment level was also an affecting factor, which controls the overall efficiency of gas injection.In the last phase of this study, the minimum miscibility pressure of the injected gas and in-situ oil under operated conditions was calculated using simulation package. These simulation runs were conducted for different percentage of CO2 in injected gas. Results of these simulation runs were in a good agreement with experimental results. It was found that as the CO2 contents of the injected gas increased the minimum miscibility pressure (MMP) decreased.

Using microorganisms is another method for removal sulfur from hydrocarbon fractions without converting their carbon structures. Nowadays biodesulfurization of crude oil fractions is considered as the most important issue. RIPI-S81 is a new DBT-desulfurizing bacterium, which is able to convert dibenzothiophene to 2-hydroxybiphenyl via 4S pathway. This bacterium isolated and depurated by department of microbiology and biotechnology, research institute of petroleum industry in Iran. In this research, we have studied removing sulfur of 4-MDBT (that it is one of alkylated derivatives of DBT) by RIPI-S81. The molecular structures of metabolites from DBT and its derivatives were analyzed using GC-MS. The reduction and conversion of 4-MDBT through the growth phase of bacterium were analyzed by HPLC. Then we obtained growth curve of RIPI-S81 in a medium containing 4-MDBT as a sole sulfur source. RIPI-S81 could desulfurize about 57 % of 4-MDBT during its growth phase in 110 hours via 4S pathway. Resting cells of this bacterium could also desulfurize 4-MDBT.

Two novel Cu (II) and Zn (II) azo pigments, [Cu(azodicyd)]n and [Zn(azodicyd)]n, where azodicyd is dianion of 4,4′-azodi(phenylcyanamide) have been synthesized. Neutral 4, 4′-azodi (phenylcyanamide) can be readily synthesized in high yields from 4, 4′-azodi (aniline) by the desulfurization reaction of its thiourea derivative. The Zn (II) and Cu (II) azo pigments can be prepared from neutral 4, 4′-azodi (phenylcyanamide) and Cu (OAC)2 or Zn (OAC) 2 in acetone- water, in the presence of triethylamine (TEA). The presence of only one sharp and very intense absorption band for the cyanamide stretching frequency in these azo pigments provides evidence that both cyanamide moieties on the phenyl rings are equivalent in the solid state. The electronic absorption spectra of azodi (phenylcyanamide) dianion in DMF show a strong visible absorption, which we have assigned to intraligand charge transfer (ILCT) (NCN-to-N=N). When azodi (phenylcyanamide) dianion coordinated to Cu (II) or Zn (II), this transition is still observed. The electronic spectrum of Cu (II) azo pigment shows a LMCT band in the visible region. These azo pigments can mix and melt with PE, PP and PVC without any thermal degradation. The DSC/TGA data show that the Cu (II) and Zn (II) azo pigments decompose at 230 and 275°C, respectively. These azo pigments are very stable in acidic, basic, oxidizing and reducing solutions.

There are two major research areas in food freezing processes. The first direction includes estimation of freezing and chilling time and the other covers the studies entailing dynamics and design of chillers and freezers. In this paper the freezing and heat transfer dynamics of fisheries products along the first above mentioned field have been investigated. The simulation results can then be used elaborately for design attitudes of industrial freezers. Through the article the freezing process is firstly modeled or fomulated and afterwards, the models have been solved numerically using finite difference methods. The results can be applied to calculate the freezing time and weight loss of product under various operational conditions such as different temperatures and cold air speeds. Also, the effect of fish (food) size, type and initial temperature has been studied. Four different models and solution methods have been used and it is demonstrated that the model of simultaneous heat and mass transfer gives the most accurate results.

The efficiencies of total petroleum hydrocarbons (TPH) transfer into various solvents from plants by microwave enhanced process were extracted. Microwave extraction - realized at 120°C for 30 min with Hexane-Acetone (3:2 V/V) as the extraction solvent was identified as the most effective extraction procedure for isolation of TPH from biotic matrices. The aim of this research is to develop a silica gel and alumina fractionation procedure for plant sample extraction. Column chromatography with two solvents (chloroform and hexane: dichloromethane) as a mobile phase were used for clean-up of extract. In this research the efficiency of recovery received from chloroform as a mobile phase. With this mobile phase color compounds and carotenoids separated with 15 ml of chloroform (first fraction) and the second fraction with 20 ml chloroform contained total petroleum hydrocarbons. At the end spectrofluorophotometry was employed for quantification of analytes.