Chemical Engineering

The object of the present paper is to give generalized relationships of space-times, for two different ordered reactions (order ?0, 1) occurring in a steady-state plug flow reactor, for special case of complete conversion. It is shown how the Hypergeometric function can be used in case of complete conversion; which in turn is related to Gauss’s pi function , given in literature [3], [4]. Several cases of working techniques with these relationships are also indicated briefly.

A study on electro less plated yarn charactertics through Box Behnken Design by various the sliver nitrate amount, temperature and time has been reported. The cotton and polyester yarns were plated with sliver nitrate by electroless plating at various concentration, temperature and time. The surface morphology, antimicrobial activity, electrical conductivity, strength and elongation have been measured for cotton and polyester silver plated yarn. It is observed from SEM image that deposition and firm attachment of sliver particle over the surface of yarn structure. It is also observed that the sliver plated yarns have better antimicrobial activity, electrical conductivity and strength than normal yarn.

The unified power quality conditioner (UPQC) is being used as a universal active power conditioning device to mitigate both current and voltage harmonics at a distribution side of power system network. This paper emphasis enhancement of power quality by using UPQC with fuzzy logic controller(FLC)and proportional- integral(PI)controller. The main purpose of the proposed (FLC)is capable of providing good static and dynamic performances compared to PID controller.

The moisture diffusion coefficient and energy activation of two Iranian apricot varieties was determined at five drying air temperatures and at a constant air velocity of 1.5 m/s. The initial moisture content (d.b.), modulus of elasticity, surface area, half of pomace thickness of halved apricot, and total soluble solids of both varieties were determined. The results showed that there were significant differences (p<0.01) in the modulus of elasticity and total soluble solids between two varieties, but no significant differences (p>0.01) were observed for other parameters. The water effective diffusion coefficient ranged from 1.34×10^-10 to 4.15×10^-10 m²/s, and from 2.03×10^-10 to 5.95 ×10^-10 m²/s, for Ghavami and Nasiry, respectively. Energy activation was 27.1 and 25.34 kJ/mol for Ghavami and Nasiry varieties, respectively. The results showed that modulus of elasticity and total soluble solids play a major role in moisture diffusion by limiting water movement within the material subjected to drying.

The potential use of Aleppo pine (Pinus halepensis Mill.), a lignocellulosic-based fiber found in discontinuous bands along the Mediterranean Basin, for the removal of a basic cationic dye: Methylene blue (MB) was investigated by adsorption in batch mode. In order to investigate the mechanism of dye sorption and potential rate controlling steps, pseudo first-order, pseudo second-order and intra-particle diffusion models equations have been used to test experimental data. Kinetic analysis of models has been carried out for initial MB dye concentration in the range of 20-100 mg/L. The rate constants models have been determined and the correlation coefficients have been calculated in order to assess which model provides the best fit predicted data with experimental results. The results showed that pseudo second-order equations model provide the best fit to experimental data for different initial MB dye concentrations implying that chemisorption mechanism may play an important role for the adsorption of dye onto Aleppo pine fibers. The results indicate also that Aleppo pine fibers adsorb Methylene blue efficiently and could be employed as a low-cost alternative in textile wastewater treatment for the removal of cationic dyes.

A teacher in an engineering college is a professional in two ways, he is an engineer and he is also a teacher. Teacher has to keep on upgrading himself in his subject and at the same time has to develop skill to translate his expertise in his field into a proper style of teaching leading to effective learning by the students. The present communication is aimed at stimulating the teacher to think, evolve and execute practice leading to effective learning by the students. Here the author presents his personal experience on some of the effective teaching techniques in teaching various subjects of Chemical Engineering at undergraduate level. Details of the methods are also given.

Rice husk, agricultural waste material of environmental  impact,  was carbonized at temperatures of 300 - 600⁰C in an oven for 2h, after which its adsorption capacities was investigated for the adsorption of acenaphthene in synthetic aqueous solution, at increasing concentrations (50–150mg/L). The yields of carbon obtained from the raw rice husk ranged from 20 - 40 % (w/w), while the adsorption capacities of rice husk increased with increasing carbonization temperature and increasing initial concentration of acenaphthene. The removal efficiencies of the rice husk increased from 71.37 - 80.56% as the carbonization temperature increased from 300-600⁰C, but decreased with increasing initial concentration of acenaphthene. The adsorption equilibrium data obtained, fitted well to the Freundlich, Langmuir, Temkin and Dubnin-Radushkevich isotherms with minimum correlation coefficient (R²) of 0.9981, 0.9262, 0.9667 and 0.9215, respectively. The error analysis showed the order of suitability of the isotherm models selected to be Temkin > Freundlich > Dubnin-Radushkevich > Langmuir. This study shows that carbons rice husk possesses favourable potency of being used as activated carbon for the removal of acenaphthene from wastewater.

Following the large reserve of untapped natural gas in the world, the utilisation of gas reserve is a possible solution to increasing energy demand and a possible reduction in pollution and crude oil dependency. Due to its (Natural gas) lower hydrocarbon fraction it can be converted to higher petroleum products such as petrol (synthetic fuel), diesel, naphtha and aviation kerosene which are products on high demand. Emission performances of hydrocarbon products produce from gas are better than those from conventional crude oil cracking process. A process known as Fischer Tropsch (F-T) process, requiring an F-T plant is used for the conversion of natural gas into higher derivatives. The process involves three basic stages; Syngas Generation, Catalytic Synthesis to form petroleum products and Hydro-processing to convert into finished product. In an attempt to ensure a major step in utilising the large gas reserve in Nigeria, the setup of F-T plant in the Niger-Delta region is proposed. The choice of establishing the F-T plant in the Niger-Delta region is not political but an economic one; this is so because the feedstock (natural gas) is available in large quantity and transportation is less, thereby cutting cost. Investors will require reasonable model variables which includes a suitable depreciation evaluation, a profitable risk portfolio and a project fixed cost, which are the responsibilities of a petroleum economist. This paper addressed a comparative study of Gas to liquid fuel as an alternative to refined crude oil. Various parameters were evaluated: physical and chemical properties of the product, emission discharge, pollutants. The results obtained showed that gas to liquid products has environmental and efficient benefits over petroleum derived products (crude oil).

DMFC has tremendous potential in serving as a source of clean and renewable energy. Different catalyst combinations are prepared and characterized in DMFC at various operating conditions. The characteristic curves are plotted. Effect of prepared catalyst in DMFC performance is analyzed at load and no load conditions. Demerits of Platinum catalyst is minimized to a great extent by the specially designed catalyst combinations. Based on the DMFC performance, the best catalyst combination (Pt-Ru/C) is identified and analysed in different operating conditions.

The Falcon SB-40 concentrator is an enhanced-gravity separator used in mineral beneficiation, as their superior gravity field enables them to separate particles within narrow classes of density and size. The process of cutting and finishing garnet mineral produces industrial waste as a fine powder mixture of garnet with a few percent of titanium carbide which is derived from titanium blades. This study aims to shed light on the Falcon concentrator’s ability to separate particles within density ranges lower than usual. Specific gravity of the fractions is 3.7 and 4.9 gm/cm3. Various operating conditions such as bowl speed (G force), water pressure, pulp solid ratio and pulp feed rate were investigated. It was shown that under optimized conditions the Falcon SB-40 concentrator can produce an excellent titanium concentrate with titanium carbide of 92.2 % from a feed waste of about 5% titanium carbide with total recovery of 97%.