Chemical Engineering

Measurements on efflux time are performed for draining a large open spherical tank through an exit pipe, the flow in the exit pipe is assumed to be laminar. Laminar flow is maintained by using different concentrations of glycerin solutions. The experimental values are compared with the mathematical model and found to be in good agreement with the model. The model is also verified for different exit pipe lengths and different volumes of liquid in the tank. Further, the effect of addition of polyacrylamide and polythene oxide polymers on drag reduction for water as well different concentrations of glycerin solutions is contemplated. It is observed that, for the range of concentrations of polymers considered, drag reduction prevails in absence of glycerin solutions only. The optimum concentration with polyacrylamide is found to be 1.25 ppm and in case of polythene oxide, it is 10ppm. However, for the case of polymer solutions of different concentrations prepared using glycerin solutions, instead of drag reduction, drag enhancement takes place. The trend is found to be same for all volumes of liquid as well as for all exit pipe lengths. This suggests that caution has to be exercised when using polymer solutions for drag reduction in gravity driven flow systems.

Tuning proportional integral and derivative (PID) controllers for Isothermal CSTR system is proposed. The PID controller is designed based on internal model control and stability analysis principles. The proposed controllers are applied to stable transfer function models of isothermal CSTR carrying out Van de Vusse reaction. Simulation results on non-linear model equations of isothermal CSTR carrying out Van de Vusse reaction is given to show the effectiveness of the proposed PID controllers. The performance under model uncertainty is also studied considering perturbation in one parameter at a time. The performance of proposed controllers is compared with the direct synthesis method (Chien et al., 2003).

Artificially contaminated soil was treated with hydrocarbon degrading bacteria previously isolated from soil that was consistently contaminated with petroleum. The consortium of bacteria used consists of Enterobacter aerogenes, Serratia marcescens and Proteus myxofaciens. immobilized in cellulosic materials such as coconut fibre and groundnut husk. The results of the laboratory tests show that the immobilized bacteria have good self life with bacteria load of 3.33 x 1022 and 3.20 x 1019 on the 1st and 28th day respectively. The immobilized bacteria system shows promise in the degradation of petroleum hydrocarbons. After 21 days of application of the immobilized bacteria system in laboratory scale degradation of Forcados light crude oil, the residual concentration of petroleum hydrocarbons decreased to 14.87% for one of the samples as compared to a residual concentration of 58.97% in the control sample. Therefore the immobilized bacteria system using cellulosic as a carrier can serve as an effective and fast bioremediation tool for cleaning up petroleum contaminated soil at low cost.

The degradation of Poly(ethylene terephthalate) and polystyrene foam waste could be accelerated using microbes. The aim of the study was to determine the degree of biodegradation of poly(ethylene terephthalate) films and Polystyrene foam by Fourier transform infrared (FTIR) spectroscopy. Further, chemical changes like formation of ester group was observed in PET powder when buried in soil under laboratory conditions. C = C bond stretching in PET powder inoculated in soil, sewage and cowdung was evident in this study. On inoculation of PET flakes in soil, sewage and cowdung, FTIR spectral analysis reveal C-H and C=C bond stretching. Except in PET flakes in cowdung , PET inoculation in soil and sewage elicited C=O bond stretching. PS powder inoculated in soil, sewage and cowdung underwent degradation which in reflected in the FTIR spectral analysis (C-O, bond stretching). Furthermore, PS powder on inoculation with sewage elicited C-H and C=C bond stretching, while in cowdung it resulted in O-H, C=O and C=C bond stretching. PS flakes when buried in soil, sewage and cowdung exhibited C=C bond stretching. In addition, O-H, C-H, C=O bond stretching was evident in PS flakes buried in cowdung. Thus fungal species (Aspergillus sp., Penicillium sp. and Fusarium sp) could be used as a biological agents to degrade PET and PS foam.

Heavy metal accumulation in waste water could affect aquatic life, human health and overall ecosystem adversely. Therefore, in recent years much emphasis has been given for the use of industrial waste water as low cost adsorbents for the removal of metallic contaminants from waste water. In this paper, the studies on removal of Cu (II) by adsorption on Limonia Acidissima hull powder as adsorbent have been investigated in a batch type experiments. The agitation time, adsorbent dosage, initial copper concentration, and the effect of solution pH are studied. Adsorption mechanism is found to follow Freundlich isotherm. The adsorption behavior is described by second order kinetics. The maximum percentage removal of copper is found to be 72.76 % for 100 ppm at pH=9 and 30⁰ C.

Global concerns about the depletion of the world`s non- renewable energy sources and the associated environmental impact of fossil fuel provided the incentives to seek alternative to petroleum based fuels. Nigeria is no exception in the fears for crude oil production going extinction as recently stated by the energy commission of Nigeria. Alternative renewable foundin vegetable oils such as palm kernel oil (PKO) abound in Nigeria forest. In this work, biodiesel was produced from palm kernel oil. Potassium hydroxide was selected to catalyze the transesterification process with methanol. The temperature was varied between 50oCand 70oC and catalyst weight varied between 2.5g and 3.5g. The highest amount of biodiesel (205 ml) was obtained at temperature of 70oC and 3.5g catalyst weight gave highest of biodiesel (210 ml). The biodiesel was characterized and the measured properties found to be closed with that of petroleum diesel. The fuel characterization carried out show that the biodiesel produced can successfully fuel a diesel engine by the level of agreement between the results obtained and fossil fuel.

Stone Mastic Asphalt (SMA) is a gap graded special mix consists of up to 80% by weight of coarse aggregate and 8 - 12% by weight of filler. The high proportion of coarse aggregate provides an interlocking stone-on-stone skeleton that resists permanent deformation. Since SMA contains large amount of filler, this paper presents an evaluation of the effects of filler type and particle size on the permanent deformation properties of SMA mixtures incorporating granite aggregates, 80/100 penetration grade asphalt, and four different fillers (limestone as control, ceramic waste, coal fly ash, and steel slag). The selected fraction of filler (10% by the total weight of aggregate) was blended in three different proportions 100/0, 50/50, and 0/100 passing the 75 and 20 micron. To determine permanent deformation characteristics of bituminous mixtures by repeated cyclic axial load indirect tensile testing using the Universal Testing Machine (UTM) in accordance with procedures outlined in BS-EN 12697-25:2005. The Repeated Load Axial Test (RLAT) and Resilient Modulus test were carried out on twelve different SMA mixtures using Marshall cylindrical samples to evaluate the effects of filler types and filler particle size on the SMA mixture deformation properties. The results and the analysis of the fundamental parameters of permanent deformation and resilient modulus have indicated the improved stiffness and the potential benefits in terms of high temperature rutting (increased stiffness and elastic response) of laboratory blended and proprietary of SMA mixtures incorporating ceramic waste and steel slag fillers with medium size particles (50/50 proportion) compared to the control mix. The coal fly ash mixtures are the least susceptible to permanent deformation.

Densities (?) and Viscosities (?) of binary mixtures of Benzaldehyde with Pentan-1-ol have been measured as a function of mole fraction at atmospheric pressure and at different temperatures of (303.15, 308.15and 313.15) K. Using the experimental data, excess volumes (VE) and deviations in viscosity (??) have been calculated. McAllister's three body-interaction model were used to correlate the kinematic viscosity of the systems. The excess volume data was fitted by means of the Redlich-Kister equation. It was found that in all cases the experimental data obtained fitted with the values correlated by the corresponding model very well. The molecular interactions existing between the components were also discussed.

Heavy metal accumulation in waste water could affect aquatic life, human health and overall ecosystem adversely. Therefore, in recent years much emphasis has been given for the use of agricultural waste as low cost adsorbents for the removal of metallic contaminants from waste water. In this paper, the studies on removal of Cu (II) by adsorption on custard apple peel powder as adsorbent have been investigated in a batch type experiments. The agitation time, the adsorbent size, adsorbent dosage, initial copper concentration, and the effect of solution pH are studied. The Freundlich model for Cu (II) adsorption onto Custard apple peel powder is proved to be the best fit followed by Langmuir model and Tempkin model based on high regression coefficient R2 value. The adsorption kinetic behavior is best described by second order. The maximum percentage removal of metal efficiency is found to be 93.97 %. The results obtained in this study illustrate that custard apple peel powder is expected to be an effective and economically viable adsorbent for Cu (II) removal from industrial waste water.

In recent years the natural supply of phenolic substances has been greatly increased due to the release of industrial byproducts into the environment. Phenol is one of the most widely used in the organic compounds in existence and is a basic structural unit for a variety of synthetic organic compounds including agricultural chemicals and pesticides. Among all the toxic compounds, phenol and its substituent phenolic compounds contribute a remarkable adverse impact to the environment. These are major xenobiotics, which are often found in the effluents discharged from the industries such as paper and pulp, textiles, gas and coke, fertilizers, The US Environmental Protection Agency (EPA, 1979) had classified the phenolic compounds as high priority pollutants due to their extensive impact on the deterioration of the water environment. In this review paper, we described about plant phenolic compounds, phenolic effects of human exposures, animal exposures, effect on children, reducing the risk of exposure and medical tests to determine concentration of phenol. Key Words: Phenol, Environment, plant phenolic compounds, Human Exposures, Animal Exposures and medical tests.