A systematic technique for cost-effective CO<Subscript>2</Subscript> emission reduction in process plants

There has been growing interests to reduce the environmental impact caused by greenhouse gas emissions from process plants through various energy conservation strategies. CO₂ emissions are closely linked to energy generation, conversion, transmission and utilisation. Various studies on the design of energy-efficient processes, optimal mix of renewable energy and hybrid power system are driven to reduce reliance on fossil fuel as well as CO₂ emissions reduction. This paper presents a systematic technique in the form of graphical visualisation tool for cost-effective CO₂ emission reduction strategies in industry. The methodology is performed in four steps. The first step involves calculating the energy consumption of a process plant. This is followed by identification of potential strategies to reduce CO₂ emissions using the CO₂ management hierarchy as a guide. In the third step, the development of “Investment” versus “CO₂ Reduction” (ICO₂) plot is constructed to measure the optimal CO₂ emission reductions achieved from the implementation of possible CO₂ reduction strategies. The Systematic Hierarchical Approach for Resilient Process Screening (Wan Alwi and Manan in AIChE J 11:3981–3988, 2006) method is used in the fourth step via substitution or partial implementation of the various CO₂ reduction options in order to meet the cost-effective emission reduction within the desired investment limit or payback period (PP). An illustrative case study on a palm oil refinery plant has been used to demonstrate the implementation of the method in reduction of CO₂ emissions. The developed graphical tool provides an insight-based approach for systematic CO₂ emission reduction in the palm oil refinery considering both heat and power energy sources. Result shows that 31.2 % reduction in CO₂ emissions can be achieved with an investment of USD 38,212 and PP of 10 months based on the present energy prices in Malaysia.     

Effect of polyacrylic acid (PAA) binder system on particle orientation during dry-pressing

Effect of polyacrylic acid (PAA) binder system on the development of particle orientation during uniaxial pressing is reported. Granules of different properties were compacted using uniaxial pressing at various pressure and their degree of particle orientation (DPO) was determined. The increment trend of DPO varies with granule strength and shows higher value for binder system of higher flexibility. Anisotropic shrinkage related to particle orientation is shown by compact of higher relative density (RD) and DPO; whereas anisotropic shrinkage related to non-uniform packing density is shown by compact of lower RD and DPO. Anisotropic shrinkage remains in the former compact while isotropic shrinkage was obtained for the latter compact at sintering temperature of 1600 °C. Subsequent cold isostatic pressing increases DPO and sintering shrinkage ratio of uniaxially pressed compacts.     

A new reactor concept for combining oxidative coupling and steam re‐forming of methane: modeling and analysis

A new and very promising application of auto‐thermal reactors is the coupling of endothermic and exothermic reactions where the product of the endothermic reaction is the desired one. Therefore, in this work, a reactor in which oxidative coupling of methane (OCM) and steam re‐forming of methane (SRM) reactions take place simultaneously was modeled. The results were obtained in a wide range of different conditions such as inlet feed, inlet temperature, portions of OCM and SRM catalysts, and inlet velocity. In selection of the catalysts, more attention was drawn to prevent re‐forming of OCM products. The main parameters of each reaction under different conditions such as conversion of the feed components, products selectivity and yield, temperature in the length of reactor, and component's concentration in the reactor were considered in course of this study. The results revealed that simultaneous OCM and SRM reactions in one reactor will tend to be auto‐thermal, and the waste of energy will be reduced. The results also show that complete conversion of water and majority of methane and oxygen will decrease the amount of unwanted products at the reactor's discharge–a constraint that exists in single reactors of each reaction specially OCM. Copyright © 2011 John Wiley & Sons, Ltd.     

Antioxidant activity of sweetgrass (Hierochloë odorata Wahlnb.) extract in lard and rapeseed oil emulsions

The antioxidant activities of sweetgrass (Hierochlo? odorata) and sage (Salvia officinalis) extracts were studied in emulsions of lard and rapeseed oil using soy lecithin as an emulsifier, and addition of cupric acetate as an oxidation catalyst. The antioxidant activity was about the same in the two substrates. The stability against autoxidation was substantially increased by both sweetgrass and sage extracts and their combination. The stability was particularly high, if citric acid and/or ascorbyl palmitate were added to plant extracts.     

Enhancement of oral bioavailability of anti-HIV drug rilpivirine HCl through nanosponge formulation*

Objective: To synthesize β cyclodextrin nanosponges using a novel and efficient microwave mediated method for enhancing bioavailability of Rilpivirine HCl (RLP).

Significance: Belonging to BCS class II RLP has pH dependent solubility and poor oral bioavailability. However, a fatty meal enhances its absorption hence the therapy indicates that the dosage form be consumed with a meal. But then it becomes tedious and inconvenient to continue the therapy for years with having to face the associated gastric side effects such as nausea.

Method: Microwave synthesizer was used to mediate the poly-condensation reaction between β-cyclodextrin and cross-linker diphenylcarbonate. Critical parameters selected were polymer to cross-linker ratio, Watt power, reaction time and solvent volume. Characterization studies were performed using FTIR, DSC, SEM, ¹H-NMR and PXRD. Molecular modeling was applied to confirm the possibility of drug entrapment. In vitro drug dissolution followed by oral bioavailability studies was performed in Sprawley rats. Samples were analyzed using HPLC.

Results: Microwave synthesis yields para-crystalline, porous nanosponges (～205?nm). Drug entrapment led to enhancement of solubility and a two-fold increase in drug dissolution (P?C_max and AUC_0-∞ increases significantly (C_max of NS～ 586?±?5.91?ng/mL; plain RLP ～310?±?5. 74?ng/mL).

Conclusion: The approach offers a comfortable dosing zone for AIDs patients, negating the requirement of consuming the formulation in a fed state due to enhancement in drugs’ oral bioavailability.     

Optimized Hybrid Block Adams Method for Solving First Order Ordinary Differential Equations

Multistep integration methods are being extensively used in the simulations of high dimensional systems due to their lower computational cost. The block methods were developed with the intent of obtaining numerical results on numerous points at a time and improving computational efficiency. Hybrid block methods for instance are specifically used in numerical integration of initial value problems. In this paper, an optimized hybrid block Adams block method is designed for the solutions of linear and nonlinear first-order initial value problems in ordinary differential equations (ODEs). In deriving the method, the Lagrange interpolation polynomial was employed based on some data points to replace the differential equation function and it was integrated over a specified interval. Furthermore, the convergence properties along with the region of stability of the method were examined. It was concluded that the newly derived method is convergent, consistent, and zero-stable. The method was also found to be A-stable implying that it covers the whole of the left/negative half plane. From the numerical computations of absolute errors carried out using the newly derived method, it was found that the method performed better than the ones with which we compared our results with. The method also showed its superiority over the existing methods in terms of stability and convergence.     

Hybrid sentiment classification on twitter aspect-based sentiment analysis

Social media sites and applications, including Facebook, YouTube, Twitter and blogs, have become major social media attractions today. The huge amount of information from this medium has become an attractive resource for organisations to monitor the opinions of users, and therefore, it is receiving a lot of attention in the field of sentiment analysis. Early work on sentiment analysis approached this problem at a document-level, where the overall sentiment was identified, rather than the details of the sentiment. This research took into account the use of an aspect-based sentiment analysis on Twitter in order to perform a finer-grained analysis. A new hybrid sentiment classification for Twitter is proposed by embedding a feature selection method. A comparison of the accuracy of the classification by the principal component analysis (PCA), latent semantic analysis (LSA), and random projection (RP) feature selection methods are presented in this paper. Furthermore, the hybrid sentiment classification was validated using Twitter datasets to represent different domains, and the evaluation with different classification algorithms also demonstrated that the new hybrid approach produced meaningful results. The implementations showed that the new hybrid sentiment classification was able to improve the accuracy performance from the existing baseline sentiment classification methods by 76.55, 71.62 and 74.24%, respectively.     

Oligomeric Composition of Polyols From Fatty Acid Methyl Ester: The Effect of Ring‐Opening Reactants of Epoxide Groups

Commercial availability of fatty acid methyl ester (FAME) from palm oil targeted for biodiesel offers a good feedstock for the production of structurally well‐defined polyols for polyurethane applications. The effect of molecular weight (MW), odd and even carbon numbers, and the linear and branched structure reactants used in the ring‐opening reaction of epoxidized fatty acid methyl ester (E‐FAME) on the properties of polyols was investigated. Conversions of E‐FAME to PolyFAME polyols were confirmed by Fourier transform infrared analysis, oxirane oxygen content, and hydroxyl number. Gel permeation chromatography (GPC) calibrated against polyether polyols as a standard and vapor pressure osmometry were used for MW determination. GPC chromatograms of PolyFAME polyols clearly demonstrated the formation of oligomers during ring‐opening reactions. MW, and odd and even carbon numbers in a structure of linear diols and branched diol used in the syntheses of PolyFAME polyols did not have an effect on crystallinity, glass transition, or melt temperatures measured using Differential scanning calorimetry (DSC). PolyFAME polyols ring‐opened with water, methanol, and 1,2‐propanediol contained secondary hydroxyl groups, whereas PolyFAME polyols ring‐opened with linear diols contained a mixture of primary and secondary hydroxyl groups. It was found that the concentration of primary hydroxyl groups increased significantly by increasing the number of carbons from C2 to C3 in the linear diols. The viscosity of PolyFAME polyols also increased with the MW of linear diols used in the E‐FAME ring‐opening reaction. These findings would be beneficial for formulators in choosing the most cost effective polyols for polyurethane formulations.