Extraction of Vegetable Oil from Avocado Seed for the Production of Biodiesel (Alkyl Ester)

The avocado seed was used as a raw material for the production of biodiesel as an alternative to petro-diesel. The oil was extracted using a soxhlet extractor with n-hexane as the solvent and transesterified with methanol (5:1 oil to methanol ratio) using potassium hydroxide as catalyst in 15 minutes reaction time. The percentage yield of the purified biodiesel was 78%. The physical and chemical properties of the biodiesel on comparison to standard biodiesel and petroleum diesel indicated that it is of good quality. It had a relative density of 0.86, cetane number of 62.2, kinematic viscosity of 3.94cst. The economies of this extraction turns avocado seed from bio-waste to wealth. Keywords: Avocado Seed, Soxhlet extractor, Biodiesel, Oil Characterization, Yield. DOI: 10.7176/JNSR/9-3-0

Effect of Activation Method and Agent on the Characterization of Prewinkle Shell Activated Carbon

The effect of activation method (physical and chemical) and the concentration of the chemical activating agents on the characterization of periwinkle shell activated carbon was investigated. The periwinkle shell was pyrolysed and activated by physical activation (using an oxidizing gas - steam) and chemical activation (using base: ZnCl2, CaCl2 and acid: H2SO4, HCl). The produced activated carbons were characterized to determine the bulk density, moisture content, pore volume, porosity, ash content, iodine number and surface area following standard ASTM procedures. The effects of concentration of the activating agents on these properties were also studied. Effects of activation method on activation carbon properties showed that the chemical activated carbon had higher bulk density, pore volume, porosity, ash content, iodine number, and surface area, while the physical activated carbon had higher moisture content. The effect of activating agent concentration showed that the bulk density, pore volume and porosity increased with concentration for base activated carbon and decreased with concentration for acid activated carbon. The ash content and iodine number fluctuated (initial increase then decrease and increase) for base activated carbon; while these parameters increased continuously and fluctuated (initial decrease the continuous increase) with concentration for acid activated carbon. The moisture content and surface area decreased with concentration for base activated carbon; these parameters fluctuated (initial increase, decrease then increase) and increased continuously for acid activated carbon. Periwinkle shell carbon chemically activated with ZnCl2 was the best activated carbon with highest density, pore volume, porosity, iodine number and surface area. Keywords: Activated carbon, Physical and Chemical activation, effect of activation agent concentration.

Determination of Optimal Yield of Alumina From Local Clays by Factorially-Designed Experiments

Leaching by use of factorial design experiment was used to investigate the effect of process variables on the yield of alumina obtainable from four local clays from four different locations in Nigeria. Characterization of these clays obtained from previous work was observed in this order: Ikot-Abasi, Enito II, Akpugo and Awgbu containing 56.00%, 8.45%, 25.28% and 14.43% Al2O3 respectively. Fractional factorial design was used to develop a mathematical model used in the investigation. The process variables whose effect on alumina leaching investigated were: acid concentration (2M and 10M), calcinations Temperature (200oC and 1000oC), calcinations time (15 and 75 minutes), leaching time (20 and 100 minutes) and particle size (75 and 1000µm) with the experiment conducted at constant boiling temperatures of the acids used (Nitric and Acetic acid). On optimization of the model developed from the factorial design experiment, optimal leaching conditions for each clay samples were obtained with corresponding yields of alumina presented as follows: Ikot-Abasi clay and nitric acid – yield of 78.86% alumina; Ikot-Abasi and Acetic – yield of 50.26% alumina; Enito II and nitric acid –  yield of 53.14% alumina; Enito II clay and acetic acid – yield of 30.23% alumina; Awgbu clay and nitric acid –  62.74% alumina yield; Awgbu clay and acetic acid – alumina yield of 43.24%; Akpugo clay and nitric acid – alumina yield 75.43%; Akpugo clay and acetic acid – alumina yield 41.98%. The values of the yields obtained from the model optimization were validated by conducting the leaching experiment again in the laboratory under the optimized process conditions and were observed to closely match with a deviation ranging from 0.21 to 5.55%. From the results obtained, it was observed that the best yield was gotten from Ikot-Abasi clay which contained the highest percentage of alumina content. DOI: 10.7176/CPER/60-03 Publication date:March 31st 201

Production of Alumina from Local Clays using Nitric and Acetic Acids

The study was carried out to investigate the effect of process variables on the production of alumina (Al2O3) by leaching of local clays obtained from four different locations in Nigeria – Ikot-Abasi, Enito II, Akpugo and Awgbu containing 56.00%, 8.45%, 25.28% and 14.43% of Al2O3 respectively.  The process variables whose effect on alumina leaching investigated were: acids concentration (2M to 10M), calcinations temperature (200oC to 1000oC), calcinations time (15 to 75 minutes), leaching time (20 to 100 minutes) and particles size (75 to 1000µm) with the experiment conducted at constant boiling temperatures of the acids used (Nitric and Acetic acid). The recommended leaching conditions used as obtained from literature were: 6M for the two acids concentrations, particles size of 150µm, calcinations and leaching time of one hour and calcinations temperature of 600oC. Upon leaching of these clays under prescribed conditions, the optimal yield obtained by varying each of the process variables were noted. Calcination temperature was observed to have the highest effect on the yield of alumina extractible providing the highest yield of alumina after analysis using mass adsorption spectrophotometer. The yield of alumina presented under the variation of calcination temperature were: Ikot-Abasi clay and nitric acid – yield of 68.10% alumina; Ikot-Abasi and Acetic – yield of 38.07% alumina; Enito II and nitric acid –  yield of 56.50% alumina; Enito II clay and acetic acid – yield of 43.41% alumina; Awgbu clay and nitric acid – 59.04% alumina yield; Awgbu clay and acetic acid – alumina yield of 46.55%; Akpugo clay and nitric acid – alumina yield 53.47%; Akpugo clay and acetic acid – alumina yield 43.23%. It was observed that Ikot-Abasi clay/nitric acid gave the best yield. Keywords: Local Clays, Alumina, Nitric Acid, Acetic Acid, Mass Adsorption Spectrophotometer. DOI: 10.7176/CPER/60-05 Publication date:March 31st 201

Simulation of Fischer-Tropsch Fluidized Bed Reactor for the Production of Methane from Synthesis Gas (Gas to Liquid Technology)

Models describing the steady state behavior of the Fischer-Tropsch Fluidized Bed Reactor has been developed. Kinetics and operating parameters of an industrial plant obtained from Dry, (2002) were adopted and used in the solution of the developed models. The model equations were integrated numerically using the Fourth-Order Runge-Kutta algorithm. Results obtained had a deviation ranging from 1.3% to 23.2% between model prediction and industrial plant output data indicating reasonable agreement. Reactor simulation with the model equations of process parameters such as superficial velocity, bubble diameter and total pressure gave: optimum yield of methane as 73% (the most significant variables) at superficial velocity of 0.0801m/s; bubble diameter of 0.0487m and a total pressure of 18 Bars. Keywords: Modeling, Simulation, Fluidized Bed Reactor, Fischer-Tropsch Synthesis

Kinetic Study of Garlic and Ginger Particles in Adsorption of Heavy Metals in Aqueous Solution

This study involved investigation and comparison of the capacity of garlic and ginger particles in adsorption of lead, cadmium and chromium ions from contaminated water. This was motivated by the perennial contamination of well water by crude oil, which carried alongside heavy metals from earth surface and other sources in contact with it while discharging from oil facilities to the subsurface region. Heavy metal analysis on the well water and crude oil from the polluted site showed high level of heavy contamination. Effect of initial concentration of heavy metals, adsorbents dosage and contact time on adsorption of the lead, cadmium and chromium ions in aqueous solution by garlic and ginger particles were studied. Garlic and ginger particles adsorption process was studied using Langmuir and Temkin isotherms. Also, to describe the kinetics of the adsorption process, the Pseudo first and second order kinetics as well as the intra-particle diffusion kinetics were used to study the experimental data. The analysis showed that the percentage of lead, cadmium and chromium ions adsorbed by garlic and ginger particles decreased as the initial concentration of metals in solution and contact time were increased. Similarly, the percentage of lead, cadmium or chromium ions adsorbed by the garlic and ginger particles at equilibrium increased as adsorbent dosages was increased due to increased effective surface area of the adsorbent. Equilibrium was attained at about 60 minutes with either garlic or ginger particles. However, garlic particles adsorbed the heavy metals more than the particles of ginger at all conditions. Also, it was observed that lead ion has more affinity to both garlic and ginger particles followed by cadmium ion. The adsorption of lead, cadmium and chromium ions were better explained by the Langmuir isotherm model than the Temkin’s isotherm model. The maximum adsorption capacity for lead, cadmium and chromium ions with garlic particles were 3.9308 mg/g, 3.3223 mg/g and 1.992 mg/g while that of ginger particles were 2.9011 mg/g, 2.3121 mg/g and 1.9543 mg/g respectively. The adsorption of lead, cadmium and chromium ions in the solution of both adsorbents revealed that diffusion and chemisorptions occurred in the adsorption process, which was best fitted in the Pseudo second order kinetics. Indicating that the Pseudo second order kinetics was the rate controlling step, and thus, will predict accurately the concentration of metal ions adsorbed. Conclusively, the garlic and ginger particles showed capacity for the removal of lead, cadmium and chromium in aqueous solution, and therefore are recommended for use in adsorption of heavy metals in wastewater. Keywords: Garlic, Ginger, Heavy metals, Adsorption Isotherm, Kinetics DOI: 10.7176/CPER/60-04 Publication date:March 31st 201

Numerical Simulation of an Industrial Absorber for Dehydration of Natural Gas Using Triethylene Glycol

Models of an absorber for dehydration of natural gas using triethylene glycol are presented. The models were developed by applying the law of conservation of mass and energy to predict the variation of water content of gas and the temperature of the gas and liquid with time along the packing height. The models were integrated numerically using the finite divided difference scheme and incorporated into the MATLAB code. The results obtained agreed reasonably well with industrial plant data obtained from an SPDC TEG unit in Niger-Delta, Nigeria. Model prediction showed a percentage deviation of 8.65% for gas water content and 3.41% and 9.18% for exit temperature of gas and liquid, respectively

Design and Simulation of Natural Gas Liquid Recovery Process from Rich Natural Gas

Natural gas plays a growing role in the energy mix by displacing coal due to its relative economic and/or environmental advantages A process of natural gas liquid (NGL) recovery utilizing internally generated energy to achieve energy efficiency was designed. The process utilizes heat generated from the compressor end of the turbo-expander to provide heat energy required to maintain the appropriate operating conditions at the intermediate and bottom sections of the demethanizer column, rather than utilizing dedicated steam generators that requires additional construction, installation, operations and maintenance cost. Simultaneously, the temperature of the hot residue gas is also dropped to the required range for export, rather than utilizing dedicated process gas coolers. The various unit operations such as heat exchangers, liquid separators, Joules Thompson Valve coefficient, demethanizer column, reflux condenser, and bottom reboiler were designed, and cost evaluation performed for each unit, while models were solved using MatLab software. The quality and composition of NGL and residue gas produced are consistent with industrial process plant data. In addition, condenser and reboiler showed that the heat removed from the condenser is 3.180.5kW and 1.65m2 area was exchanged, while the heat for the reboiler is 474.5kW at 47.25m2 exchanged area. Also, the temperature profile of the demethanizer column is not uniform as lower temperature is required for the rectifying section (cryogenic absorption). Thus, temperature of -90oC to – 95oC favours the production of sales gas as the top product stream, while a temperature range of 30oC to 36oC at the bottom favours the recovery of NGL product as the bottom stream. The height and diameter of demethanizer column for distillation and absorption sections are 28m and 1.55m and 7.24m and 3m respectively. Keywords: Natural Gas Liquid, Heat Exchanger, Separator, J-T Valve, Demethanizer Column, DOI: 10.7176/CPER/64-04 Publication date: January 31st 202