The use of bio-diesel based additive as rheology improver and pour point depressant of Nigerian waxy crude

The chemical method has proved to be the most effective mitigating method of wax deposition in petroleum system as it deals with the root cause of wax formation. Most of the commercial chemicals in the industry are very expensive and toxic. This paper aims the use of biodiesel based additives for improving the rheological behavior and pour points of waxy crude from Nigeria field. The biodiesels derived additives gave better performance than the commercial chemical and the seed oils as greatly improvement in rheology and pour point values of the waxy crude were observed     

Optimization of kinetic data for two‐stage batch adsorption of Pb(II) ions onto tripolyphosphate‐modified kaolinite clay

BACKGROUND: Most adsorption studies consider only the adsorption of pollutants onto low cost adsorbents without considering how equilibrium and kinetic data can be optimized for the proper design of adsorption systems. This study considers the optimization of kinetic data obtained for the removal of Pb(II) from aqueous solution by a tripolyphosphate modified kaolinite clay adsorbent. RESULTS: Modification of kaolinite clay with pentasodium tripolyphosphate increases its cation adsorption capacity (CEC) and specific surface area (SSA) from 7.81 to 78.9 meq (100 g)^?1 and 10.56 to 13.2 m² g^?1 respectively. X‐ray diffraction patterns for both unmodified and tripolyphosphate‐modified kaolinite clay suggest the modification is effective on the surface of the clay mineral. Kinetic data from the batch adsorption of Pb(II) onto the tripolyphosphate‐modified kaolinite clay adsorbent were optimized to a two‐stage batch adsorption of Pb(II) using the pseudo‐second‐order kinetic model. Mathematical model equations were developed to predict the minimum operating time for the adsorption of Pb(II). Results obtained suggest that increasing temperature and decreasing percentage Pb(II) removal by the adsorbent enhanced operating time of the adsorption process. The use of two‐stage batch adsorption reduces contact time to 6.7 min from 300 min in the single‐stage batch adsorption process for the adsorption of 2.5 m³ of 500 mg L^?1 Pb(II) under the same operating conditions. CONCLUSION: Results show the potential of a tripolyphosphate‐modified kaolinite clay for the adsorption of Pb(II) from aqueous solution and the improved efficiency of a two‐stage batch adsorption process for the adsorption of Pb(II) even at increased temperature. Copyright © 2009 Society of Chemical Industry     

Effect of cassava varieties on the sorption isotherm of tapioca grits

Cassava (Manihot esculenta Cranzt) deteriorates rapidly. Hence it is processed into various products within 2 to 3 days after harvesting. For this work, tapioca was produced from three different varieties of cassava. They are Odongbo, Okoiyawo and TMS30572. The sorption isotherm for the tapioca grits from three different varieties of cassava at temperatures 25, 32 and 45 °C were determined experimentally and modelled using five different models. Using analysis of variance at 0.01 level, it was shown that the experimental sorption isotherms of the tapioca from the various cassava varieties are not significantly different from each other. However, the Guggenheim (1966) , Anderson (1946) & de Boer (1953) (GAB) model gave the best fit for sorption isotherm of tapioca from either the Odongbo or Okoiyawo varieties, while the exponential model was the best for that from TMS30572 variety.     

Entropy generation minimization on electromagnetohydrodynamic radiative Casson nanofluid flow over a melting Riga plate

Minimizing entropy generation is a technique that helps improve the effectiveness of real processes by studying the associated irreversibility of system performance of nanofluid. This study examines the entropy generation analysis of electromagnetohydrodynamic radiative Casson flow induced by a stretching Riga plate in a non-Darcian porous medium under the influence of internal energy change, Arrhenius activation energy, chemical reaction, and melting heat transfer. The thermophysical features of the fluid are assumed constant in most of the literature. However, this current research bridges this gap by considering viscosity, conductivity, and diffusivity as temperature-dependent variables. Also, the exponential decaying Grinberg term is used as a resistive force in this investigation due to the electromagnetic properties of the Riga plate in the momentum conservation equation. Some suitable dimensionless variables are introduced to remodel the transport equations into unitless ones and then solved numerically by employing Galerkin Weighted Residual Method. Analyses reveal that the Casson parameter declines the fluid velocity, while the existence of the melting parameter has the opposite effect. Also, this article includes some future recommendations.     

Asymmetric supercapacitor based on novel coal fly ash derived metal–organic frameworks as positive electrode and its derived carbon as negative electrode

Journal of Applied Electrochemistry - The paper presents a comparative study between aluminum fumarate metal–organic framework (Al-FumMOF) and a novel coal fly ash derived aluminum MOF...     

Modification and properties of African yam bean (Sphenostylis stenocarpa Hochst. Ex A. Rich.) Harms starch I: Heat moisture treatments and annealing

African yam bean (Sphenostylis stenocarpa) starch was subjected to heat moisture treatments at 18% (HMT-18), 21% (HMT-21), 24% (HMT-24), 27% (HMT-27) and excess (Annealing) moisture levels. Proximate chemical composition of the starch samples revealed that the moisture content of the starches ranged between 6.7% and 12.5%. Following modification of the native starch, there was a reduction in the moisture level of the heat moisture treated starches from HMT-18 to HMT-27. However, the annealed starch (HMT-ANN) retained higher moisture content compared to native starch (AYB-Native). The carbohydrate, protein, ash, amylose and fat content reduced with all the forms of heat treatments. At the temperature range studied (60–90 °C), increasing level of heat moisture treatments reduced the solubility and swelling capacity. pH also exert a profound effect both on the solubility and the swelling of the starch. Increasing degree of alkalinity increased both solubility and swelling capacity. In the native and modified starch samples, replacement of the wheat flour by the starch resulted in increased alkaline water retention of the blends. Water absorption capacity of the starch increased with the severity of moisture treatments, while the oil absorption capacity decreased. Apart from HMT-18, there was improved gel forming capacity of all the other heat-modified starches.Pasting temperature increased after hydrothermal modifications, whereas peak viscosity (P_v), Hot Paste Viscosity (H_v), setback and breakdown values all reduced after heat moisture treatments. All the starches were of type-B viscosity.Differential scanning calorimetry studies revealed that heat moisture treatment shifted the onset temperature (T_o), peak temperature(T_p) and conclusion temperature (T_c) to higher values. The gelatinisation temperature of the annealed starch was comparable to native starch. In addition, gelatinisation band of the native starch increased progressively from HMT-18 to HMT-27. Heat moisture treatment reduced the gelatinsation enthalpy (ΔH), while the enthalpy of retrogradation(ΔH_r) increased with the storage time of the gelatinised starch. Retrogradation enthalpy of the heat moisture conditioned starches were lower than the value obtained for the native starch.X-ray diffraction studies of the starch indicated that all the starch samples showed the type-C diffraction pattern. Differences were however observed in their degree of crystallinity. Native starch exhibited the lowest crystallinity (20%) while annealed starch had the highest crystallinity (27%)Microscopy studies revealed surface indentation, formation of groves in the central region, folding of starch granules and formation of doughnut-like appearance in some of the starch samples.     

Functional and tableting properties of acetylated and oxidised finger millet (Eleusine coracana) starch

The functional and tableting properties of native (NaFM) and chemically modified (by acetylation, AcFM; and oxidation, OxFM) finger millet starches were investigated. The tablet formation properties of the starches were assessed by Heckel and Kawakita analysis. The swelling power and solubility of the starch increased with increase in temperature with AcFM having the highest swelling power, while OxFM had the highest solubility. X‐ray diffractometry showed that the starches had the characteristic ‘A’ pattern with strong peaks at 3.78, 4.37, 4.87, and 5.17 Å. Chemical modification causes rupture of some starch granules as revealed by the Scanning Electron Micrograph. Chemical modification also leads to improved gelatinisation profile, with reduction in ΔH_gel from 9.64 J/g (NaFM) to 3.88 J/g (AcFM) and 8.76 J/g (OxFM). The bulk density and Hausner's ratio increased after chemical modification of the starch. Chemical modification reduced the mean yield pressure, P_y (Heckel analysis) but increased the deformability P_k (Kawakita analysis) of the starch compacts. Chemical modification also increased the crushing and tensile strength of the starch compacts, but lowered its disintegration time and friability.     

The acylated protein derivatives of Canavalia ensiformis (jack bean): A study of functional characteristics

Protein concentrate was prepared from jack bean (JNP) and it was modified by acylation using acetic (JAP) and succinic anhydrides (JSP). Proximate analyses revealed that moisture and ash content increased following acetylation and succinylation, while both acetylation and succinylation reduced percentage crude fat and protein. Acetylation and succinylation reduced protein solubility in the acidic pH range below the isoelectric point (4.5) of the protein concentrate but improved the solubility of the unmodified protein concentrate at the isoelectric point and pH range alkaline to the isoelectric point. Both acetylation and succinylation increased the water absorption capacity of unmodified protein concentrates at all levels of ionic strength investigated (0.1-1.0 mol/l). Acetylation improved oil absorption capacity whereas the tendency to absorb oil reduced after succinylation. Maximal emulsifying activity of native and modified proteins were obtained at pH 10. Emulsion stability of acylated proteins was higher than those of native proteins in the range of pH 4-10 but lower when the pH was 2. Foam capacity and stability of both native and modified proteins increased with increase in protein concentration. Foam capacity of modified proteins increased progressively with increase in pH from 2 to 10. Also, acylated protein derivatives had improved foam capacity over the native protein except at pH 2. Gelation capacity of both native and modified proteins was maximal at the region of isoelectric point.     

Pasting,Thermal, Hydration,and Functional Properties of Annealed and Heat-Moisture Treated Starch of Sword Bean (Canavalia gladiata)

The effects of annealing (ANN) and heat-moisture treatments (HMT) on the physicochemical and functional properties of Sword bean starches were investigated. The pasting properties differ significantly among the starches, with peak viscosity ranging from 399.17 RVU to 438.33 RVU; however, all the starches exhibited ‘Type C’ class with restricted swelling. The HMT starches had the highest gelatinization temperature, while change in enthalpy of gelatinization, ΔH_gel of the native starch, was higher (13.82 J/g) than that of the modified starches (1.39–6.74 J/g). The solubility and swelling power of all the starches increased as the temperature increased. The oil and water absorption capacity of the starches ranges between 3.24–3.91 g/g and 2.42–3.35 g/g, respectively. HMT (at 25 and 30% moisture level) changes the X-ray diffraction pattern of the starch from Type ‘B’ to Type ‘C’. The Scanning electron micrograph results revealed the starch granules with smooth ellipsoids and indentation in their centre, hydrothermal modification showed little effect on the morphology and size of the granules. Hydrothermal modification improved the physicochemical and functional properties of the starch without destroying the granule of the starch.