The growing environmental concerns on the toxicity and flammability of hexane motivate the need to obtain a more environmentally friendly solvent capable of extracting as much oil as hexane or even more, while giving acceptable oil quality. This study therefore investigated the possibility of replacing Hexane with either Ethanol or the mixtures of both in the extraction of Neem Oil from Neem seed. It was observed that as the extraction time increased, oil yield increased, though there was little or no increase in oil yield at 5hours and 6 hours of operations. At different extraction time, Hexane produced oil yields greater than that obtained from Ethanol. Hence, Ethanol did not prove to be a good replacement for Hexane, even at higher temperature of 750C for Ethanol. Optimum temperature of extraction was found to be 550C. Surprisingly, mixtures of Ethanol and Hexane gave commendable results. Particularly, Ethanol-Hexane mixtures of 60/40, 50/50, and 40/60 % (volume proportions) gave better oil yields of 44%, 43% and 41.2% respectively than that of Hexane (40.25%) at the 6 hours of operation, thereby making the combinations good substitutes for Hexane.
Activated carbon was produced from palm-kernel
shell using NaOH and KOH solutions as the activating agents.
The same was tested to determine its adsorptive capacity and
efficiency using methylene blue solution. Particle sizes of the
produced carbon were in the range of 600 – 2000 μm. The
adsorption process was carried out at two different temperatures
using methylene blue as adsorbate. It was observed that
adsorption of methylene blue dye using carbon activated
impregnated with KOH gave better result than with NaOH.
Based on the adsorption parameters obtained, the process was
found to be better described by the Freundlich adsorption
isotherm.
Sewage sludge is a very harmful waste when improperly discharged into the environment because of its inherent abundant pathogens, organic pollutants, and heavy metal constituents. The pyrolysis of sewage sludge is viewed not only to reduce pollutants associated with it but also one of the viable alternative sources for renewable energy or biofuel production. In this study, the effect of catalyst and temperature on the yield and composition of bio-oil obtained from the catalytic and non-catalytic pyrolysis of desludging sewage samples (DSS) was investigated. Modified pyrolysis reactor was used to pyrolyze the DSS at temperature ranges of 300–400,400–500,500–600 and 600–700 ℃ with and without the use of zeolite-Y catalyst. The 'heterogeneous' catalysis reaction yielded 20.9 wt% bio-oil, while the reaction without catalyst yielded 18.2 wt% bio-oil. Pyrolysis of the DSS favored char yield of between 55.4 and 76.6 wt%. The X-ray Fluorescence (XRF) analysis showed high silica (46 and 56.1 wt%), calcium (20.9 and 15.50 wt%), and low organic matter (12 and 12.87 wt%) contents present in the desludging feedstock before and after pyrolysis respectively. The gas chromatography–mass spectrometry (GCMS) analysis indicated the presence of nitrogen-containing compounds (between 20 and 50 wt%), mono-aromatics (18 and 28 wt%) and oxygenated compounds, in the form of carboxylic acids, aliphatics, ketones, ethers, esters and aldehydes in the bio-oils. Pyrolysis process development is, therefore, essential to clean the environment of pollutants from sewage sludge, by its conversion to more useful chemicals. In contrast, sewage sludge with high silica content may be tailored to the production of building materials.
Abstract Demulsification is a method used to reduce or disrupt the water - crude oil emulsion system without uttering the initial composition of the crude oil. This process is done by the introduction of chemicals called demulsifiers, which break the emulsion into aqueous and organic phases. In this study, the demulsifier formulated was the base-catalyzed phenol-formaldehyde resin known as the resoles, with the ratios of phenol to formaldehyde, varied between 1.0:1.2 and 1.0:2.0. The different samples of resoles where then ethoxylated to make them more hydrophilic using different weights (10, 15 & 20 g) of polyethylene glycol (PEG). Screening of the ethoxylated demulsifiers was done using the established bottle test procedure, at 70 °C, the concentration of 50 ppm, and 20 minutes of residence or separation time, in order to select the most effective demulsifier, based on the amount of water removed from the emulsion. The best chemical-demulsifier produced was the ethoxylated resole, which was then blended with xylene at varying percentages (0, 20, 40, 50, and 80 % weight/weight) and was further screened, using the bottle test method. From the analysis, it was obtained that the most effective ethoxylate-xylene demulsifier blend was sample DR3, and made of formaldehyde to phenol ratio of 1.8:1, 20 g of PEG 400 blended with 20 % xylene. The demulsifier gave a water separation efficiency of 85.7 %, compared with the commercial demulsifier, which yielded 72.7 %. The result indicates the practical significance of solvent modified demulsifiers for separating crude oil emulsions in the petroleum industries.
Surfactants are known for their unique property in lowering the interfacial tension (IFT)
amid fluids injected and heavy crude oil of 22.3°API. In this present work, an original
surfactant was formulated from natural oil (Castor oil) to see its use in enhanced oil
recovery. The results from interfacial tension reduction by the castor oil-based
surfactant were compared to that of the industrial surfactant (Methyl ester sulfonate).
The IFT between the aqueous phases was measured then the effect of the surfactants
was studied in core flooding experiments. The IFT was found to be reduced to as low as
12.1 mN/m using the castor-based surfactant and 12.3 mN/m using the industrial
surfactant. The influence of brine concentration on IFT was also investigated. Results
from core floods showed that the range of oil recovery after waterflood is in the range of
30-40% and the additional recovery from surfactant flooding in the range of 35-46%.
In this study, the chemical compositions of waste okra stalks and rice husks were investigated and their use, evaluated as raw materials for the Kraft pulping process. Pulp yield, Consistency and 1% NaOH solubility were determined. Both raw materials were dried, and the chemical compositions obtained prior to cooking/digestion in a 15 L autoclave. While properties such as moisture content, 1% NaOH solubility, extractives and hot water solubility seem to favour raw rice husk, the pulp yield was very low (25.7%) as against the pulp yield from okra (41.2%). The high ash content and Silicates/Silica in rice husk (6.1–45.82% and 20480ppm respectively) will pose problems in the liquor recovery stage in the process. Therefore, the okra stalk is a better raw material for pulp and paper making than the rice husk. From this study, waste okra stalk is found to possess some economic value and can no longer be left to become a nuisance to the environment.
Abstract In the course of chemical flooding of crude oil reservoirs with surfactants, retention of surfactant particles in the pores of the reservoir rock can cause a major reduction of the reservoir permeability. This can cause serious problems thus unfavourably influencing the economics of oil recovery. An appropriate assessment of the reduction in permeability is essential for the recovery of hydrocarbons. During tertiary recovery of crude oil, a critical evaluation of formation damage is necessary to evade operating costs, as the reservoir rock is extremely sensitive to chemicals injected. The extent to which permeability is reduced cannot be comprehensive for core field scales; it is consequently paramount to study the reduction in the permeability of a core at laboratory scale before field scale estimation. In this paper, an experimental investigation on the reduction in permeability after surfactant injection cores is presented. Surfactants were used to flood the core samples. The permeability of the cores was calculated at the beginning and end of every flood by measuring the differential pressure during surfactant flooding of the cores. From the results, it is evident that there is a strong influence of surfactants on the process of adsorption on reservoir rocks and consequently leading to reduction in permeability.
With the fast depletion of fossil fuel sources for energy production and coupled with their negative impacts on the environment, the continued search for alternative sources that are renewable, sustainable and environmentally friendly has become imperative. This research examined the performance of sodium borohydride for the production of hydrogen gas using 5 ml each of organic acid (acetic acid), spoilt extracts of citrus fruits (lime, lemon and orange) without the use of neither catalyst nor heat source. A three neck flat bottom flask was used in which sodium borohydride was reacted with extracts from the three spoilt fruits and acetic acid with concentrations of 1, 5, 7, 12 and 17.5 M. Volume of hydrogen gas produced were recorded and the results revealed that using 7 M solution of acetic acid and 1.0 gram sodium borohydride generated the highest volume of 2460 ml of hydrogen gas in 63.72 min while the undiluted extracts of spoilt orange, lemon and lime gave 100 ml in 0.68 min, 90 ml in 1.67 min and 60 ml in 0.5 min respectively. For the diluted fruit extracts, lime, orange and lemon at a dilution factor of 2 each, generated hydrogen gas of 80ml in 0.5 min, 70ml in 1.3 min and 70ml in 0.62 min respectively. All the reactions took place at an ambient temperature of 27°C. Being able to conveniently retrieve hydrogen from its combined state when needed would advance the use of hydrogen as a source of energy.
Palm kernel and soybean oils were used as raw materials to produce lube oils. Their transesterification/conversion processes were investigated for different catalyst-oil concentrations. The optimum conditions for obtaining biolubricants with improved properties were found to be close for both oils. For the palm kernel oil, the maximum conversion of the triglyceride to methyl ester was 98 % at an optimum temperature of 56 oC for catalyst concentration of 0.6, 6:1 methanol-oil ratio and lube oil yield of 92 %, while for soybean oil, the conditions for maximum conversion (95%) of the triglyceride in the soybean oil occurred at 60 oC, for 0.5 catalyst concentration and 6:1 methanol-oil ratio with lube oil yield of 88 %. Furthermore, the PKO gave higher biolube oil yield compared to soybean oil. The addition of ethylene glycol coupled with subsequent blending of the oils with mineral oils helped to modify the products of the second transesterification which resulted in the desired lube oils.
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