Showing papers in "Industrial & Engineering Chemistry Research in 2006"

Waste cooking oil – an economical source for biodiesel: a review

Abstract: Biodiesel (fatty acid methyl ester) is a nontoxic and biodegradable alternative fuel that is obtained from renewable sources. A major hurdle in the commercialization of biodiesel from virgin oil, in comparison to petroleum-based diesel fuel, is its cost of manufacturing, primarily the raw material cost. Used cooking oil is one of the economical sources for biodiesel production. However, the products formed during frying, such as free fatty acid and some polymerized triglycerides, can affect the transesterification reaction and the biodiesel properties. Apart from this phenomenon, the biodiesel obtained from waste cooking oil gives better engine performance and less emissions when tested on commercial diesel engines. The present paper attempts to review methods for the transesterification of waste cooking oil and the performance of biodiesel obtained from waste cooking oil in a commercial diesel engine. The paper also examines the basic chemistry involved during frying and the effects of the products formed in the frying process on biodiesel quality.

Electrohydraulic Discharge and Nonthermal Plasma for Water Treatment

Abstract: The application of strong electric fields in water and organic liquids has been studied for several years, because of its importance in electrical transmission processes and its practical applications in biology, chemistry, and electrochemistry. More recently, liquid-phase electrical discharge reactors have been investigated, and are being developed, for many environmental applications, including drinking water and wastewater treatment, as well as, potentially, for environmentally benign chemical processes. This paper reviews the current status of research on the application of high-voltage electrical discharges for promoting chemical reactions in the aqueous phase, with particular emphasis on applications to water cleaning.

CO2 Capture Capacity of CaO in Long Series of Carbonation/Calcination Cycles

Abstract: Calcium oxide can be an effective sorbent to separate CO2 at high temperatures. When coupled with a calcination step to produce pure CO2, the carbonation reaction is the basis for several high-temperature CO2 capture systems. The evolution with cycling of the capture capacity of CaO derived from natural limestones is experimentally investigated in this work. Long series of carbonation/calcination cycles (up to 500) varying different variables affecting sorbent capacity have been tested in a thermogravimetric apparatus. Calcination temperatures above T > 950 °C and very long calcination times accelerate the decay in sorption capacity, while other variables have a comparatively modest effect on the overall sorbent performance. A residual conversion of about 7−8% that remains constant after many hundreds of cycles and that seems insensitive to process conditions has been found. This residual conversion makes very attractive the carbonation/calcination cycle, by reducing (or even eliminating) sorbent purge ra...

Heterogeneous Catalytic Deoxygenation of Stearic Acid for Production of Biodiesel

Abstract: A novel method for production of diesel-like hydrocarbons via catalytic deoxygenation of fatty acid is discussed. The model compound stearic acid is deoxygenated to heptadecane, originating from the stearic acid alkyl chain. The deoxygenation reaction is carried out in a semibatch reactor under constant temperature and pressure, 300 °C and 6 bar, respectively. A thorough catalyst screening was performed to obtain the most promising metal and support combination. The catalysts were characterized by N2-physisorption, CO-chemisorption, and temperature-programmed desorption of hydrogen. A highly active and selective in the deoxygenation reaction of stearic acid carbon supported palladium catalyst converted stearic acid completely with >98% selectivity toward deoxygenated C17 products.

Hydrogen Membrane Separation Techniques

Abstract: About 80% of the present world energy demand comes from fossil fuels. Unlike using fossil fuels, using hydrogen as an energy source produces water as the only byproduct. Use of hydrogen as an energy source could help to address issues related to energy security including global climate change and local air pollution. Moreover, hydrogen is abundantly available in the universe and possesses the highest energy content per unit of weight compared to any of the known fuels. Consequently, demand for hydrogen energy and production has been growing in the recent years. Membrane separation process is an attractive alternative compared to mature technologies such as pressure swing adsorption and cryogenic distillation. This paper reports different types of membranes used for hydrogen separation from hydrogen-rich mixtures. The study has found that much of the current research has been focused on nonpolymeric materials such as metal, molecular sieving carbon, zeolites, and ceramics. High purity of hydrogen is obtain...

Adsorption of Ni(II) from Aqueous Solution Using Oxidized Multiwall Carbon Nanotubes

Abstract: In this work, oxidized multiwall carbon nanotubes (MWCNTs) were used as a novel adsorbent for removing Ni(II) from aqueous solution. The adsorption of Ni(II) onto oxidized MWCNTs was studied as a function of contact time, pH, ionic strength, MWCNT concentration, and temperature. The results showed that Ni(II) adsorption onto MWCNTs is strongly dependent on pH and oxidized MWCNT concentration and, to a lesser extent, ionic strength. Kinetic data indicated that the adsorption process achieved equilibrium within 40 min and follows a pseudo-second-order rate equation. The adsorption data fit the Langmuir model and its linearized form well, together with thermodynamic data indicating the spontaneous and endothermic nature of the process. Results of a desorption study showed that Ni(II) adsorbed onto oxidized MWCNTs could be easily desorbed at pH <2.0. Ion exchange may be the predominant mechanism of Ni(II) adsorption on oxidized MWCNTs. Oxidized MWCNTs may be a promising candidate for concentration of heavy me...

Pilot Plant Studies of the CO2 Capture Performance of Aqueous MEA and Mixed MEA/MDEA Solvents at the University of Regina CO2 Capture Technology Development Plant and the Boundary Dam CO2 Capture Demonstration Plant

Abstract: Evaluations of the benefits of using a mixed MEA/MDEA solvent for CO2 capture in terms of the heat requirement for solvent regeneration, lean and rich loadings, CO2 production, and solvent stability were performed by comparing the performance of aqueous 5 kmol/m3 MEA with that of an aqueous 4:1 molar ratio MEA/MDEA blend of 5 kmol/m3 total amine concentration as a function of the operating time. The tests were performed using two pilot CO2 capture plants of the International Test Centre for CO2 Capture (ITC), which provided two different sources and compositions of flue gas. The University of Regina CO2 plant (UR unit) processes flue gas from the combustion of natural gas while the Boundary Dam CO2 plant (BD unit) processes flue gas from a coal-fired electric power station. The results show that a huge heat-duty reduction can be achieved by using a mixed MEA/MDEA solution instead of a single MEA solution in an industrial environment of a CO2 capture plant. However, this benefit is dependent on whether the...

Acid-catalyzed production of 5-hydroxymethyl furfural from d-fructose in subcritical water

Abstract: A batch-type subcritical water system was used to perform the decomposition reaction of d-fructose to 5-hydroxymethy furfural (HMF) over a temperature range of 473−593 K. The catalytic effect of various organic and inorganic acids with pH values in the range of 1.5−5 was evaluated. It was found that not only the pH, but also the nature of the acids, had great influence on the decomposition pathway. At lower pH, a rehydration of HMF to levulinic and formic acids occurred, whereas at higher pH, polymerization reactions occurred. Phosphoric acid (pH 2) was determined to give good balance between activity, yield, and byproduct amounts. The optimum condition for the best yield of HMF (65%) was achieved at a temperature of 513 K for a residence time of 120 s. The decomposition reaction of other monosaccharides and disaccharides were also investigated, and it was determined that the ketohexoses give higher yields than aldohexoses. However, all saccharides showed the possibility of the conversion to HMF in subcri...

The Production of Propene Oxide: Catalytic Processes and Recent Developments

Abstract: Propene oxide, which is one of the major commodity chemicals used in chemical industry, desperately requires a new process for its production, because of the disadvantages that are encountered with the currently available processes. This paper discusses the existing processes used for the production of propene oxidethe chlorohydrin and hydroperoxide processesand their advantages and disadvantages. Furthermore, the new processes and catalysts under development for the propene oxide production are discussed, as well as the challenges that are still limiting the applications of some of those prospects. The most important new developments for the production of propene oxide discussed in this paper are: the hydrogen peroxide combination process, the ethene oxide alike silver catalysts, the molten salt systems, and the gold−titania catalyst systems.

Wet Oxidation and Catalytic Wet Oxidation

Abstract: This review article explores three major aspects of the wet oxidation (WO) and catalytic wet oxidation (CWO) processes (with the major focus being on WO and CWO, using air or oxygen as an oxidant). These aspects are (a) the fundamental chemistry of WO/CWO; (b) important aspects of catalysts, with regard to the CWO process; and (c) engineering aspects of the WO/CWO process. The applications of WO and CWO technology to treat industrial wastewater clearly illustrate the potential of these processes for treating wastewater from a wide number of industries. WO/CWO is a fertile area of research with significant scope for further research and innovation, particularly in the areas of catalyst development, the understanding of catalytic mechanisms, and the fundamental chemistry that occurs during WO/CWO. Selected examples of findings to date are discussed in this review.

Transesterification of Soybean Oil to Biodiesel by Using Heterogeneous Basic Catalysts

Abstract: Biodiesel production has increased greatly in recent years, because of the less-detrimental effects of this fuel on the environment, compared to a conventional diesel obtained from petroleum. This work investigates the possibility of using MgO and calcined hydrotalcites as catalysts for the transesterification of soybean oil with methanol. The achieved experimental data show a correlation not only with the catalysts basicity, but also with its structural texture. However, the structural texture of the examined catalysts is dependent on both the precursor and the preparation method. At least four different types of basic sites have been individuated on the surface of MgO and calcined hydrotalcite catalysts. The strongest basic sites (super-basic) promote the transesterification reaction also at very low temperature (100 °C), while the basic sites of medium strength require higher temperatures to promote the same reaction. Ultimately, all the tested catalysts are resistant to the presence of moisture in the...

Effects of Boron Doping on Photocatalytic Activity and Microstructure of Titanium Dioxide Nanoparticles

Abstract: Boron-doped TiO2 nanoparticles were prepared by the sol−gel method and characterized by XRD, TEM, XPS, FT-IR, and UV−vis spectroscopy. XRD results showed that the doping of boron ions could efficiently inhibit the grain growth and facilitate the anatase-to-rutile transformation prior to the formation of diboron trioxide phase. FT-IR and XPS results revealed that the doped boron was present as the form of B3+ in B-doped TiO2 samples, forming a possible chemical environment like Ti−O−B. The lattice parameters at different boron contents and calcination temperatures indicated that B3+ was likely to weave into the interstitial TiO2 structure. The photocatalytic activity of the B-doped TiO2 nanoparticles was evaluated by the photoregeneration of reduced nicotinamide adenine dinucleotide (NADH). All B-doped TiO2 nanoparticles calcined at 500 °C showed higher photocatalytic activity than pure TiO2 sample in the photocatalytic reaction of NADH regeneration under UV light irradiation. When the molar ratio of B to ...

Applications of Pore-Expanded Mesoporous Silicas. 3. Triamine Silane Grafting for Enhanced CO2 Adsorption

Abstract: Conventional MCM-41 and pore-expanded MCM-41 (PE-MCM-41) silicas have been used as supports for grafting 3-[2-(2-aminoethylamino)ethylamino]propyl trimethoxysilane (TRI) and tested for CO2 adsorption. The effects of the quantity of triamine silane added to the grafting mixture on the CO2 adsorption capacity and apparent adsorption rate have been examined. The results showed that when both supports were grafted under the same conditions, PE-MCM-41 was grafted with slightly larger quantities of amine than MCM-41, for all controlled silane additions. Based on the adsorption performance of the materials using a dry 5% CO2/N2 feed mixture, the optimal quantity of triamine silane added to the grafting mixture was determined to be ca. 3.0 cm3/g(SiO2), for both MCM-41 and PE-MCM-41. The CO2 adsorption capacity of TRI−PE-MCM-41 was significantly higher than that of TRI−MCM-41. Furthermore, the dynamic adsorption performance of TRI−PE-MCM-41 was far superior to TRI−MCM-41. In comparison to 13X zeolite, TRI−PE-MCM-4...

Ten Years with the CPA (Cubic-Plus-Association) Equation of State. Part 1. Pure Compounds and Self-Associating Systems

Abstract: CPA (Cubic-Plus-Association) is an equation of state that is based on a combination of the Soave−Redlich−Kwong (SRK) equation with the association term of the Wertheim theory. The development of CPA started in 1995 as a research project funded by Shell (Amsterdam), and the model was first published in 1996. Since then, it has been successfully applied to a variety of complex phase equilibria, including mixtures containing alcohols, glycols, organic acids, water, and hydrocarbons. Focus has been placed on cases of industrial importance, e.g., systems with gas-hydrate inhibitors (methanol, glycols), glycol regeneration and gas dehydration units, oxygenate additives in gasoline, alcohol separation, etc. This manuscript, which is the first of a series of two papers, offers a review of previous applications and illustrates current focus areas related to the estimation of pure compound parameters, alcohol−hydrocarbon vapor−liquid equilibria (VLE) and solid−liquid equilibria (SLE), as well as aqueous systems. Th...

Removal and Recovery of the Hazardous Azo Dye Acid Orange 7 through Adsorption over Waste Materials: Bottom Ash and De-Oiled Soya

Abstract: An azo dye, Acid Orange 7 [p-(2-hydroxy-1 naphthylazo)benzene sulfonic acid] was removed by adsorption over two waste materials, namely, bottom ash, a power plant waste, and de-oiled soya, byproduct obtained during the processing of soybean in soya oil extraction mills. Both waste materials showed excellent adsorption abilities and can be treated as low-cost adsorbents. The adsorbents were characterized through IR spectroscopy and differential thermal analysis (DTA), and preliminary investigations were carried out by batch adsorption to examine the effects of pH, adsorbate concentration, sieve size, adsorbent dosage, contact time, and temperature. A plausible mechanism for the ongoing adsorption process and thermodynamic parameters were also obtained from Langmuir and Freundlich adsorption isotherm models. The kinetic measurements helped in determining the specific rate constant, confirming the applicability of the first-order rate expression. To identify whether the ongoing process is particle diffusion ...

Hindrance Factors for Diffusion and Convection in Pores

Abstract: It is well-known that solutes in liquid-filled pores of molecular dimensions have reduced diffusivities and are sieved during filtration. For solute molecules that are large enough to act as hydrodynamic particles, these phenomena can be explained by a combination of particle−wall hydrodynamic interactions and steric restrictions. Theoretical expressions that include those effects have been available for many years, but, even for spheres in pores of constant cross-section, certain hydrodynamic information has been lacking until recently. In particular, the local enhanced drag and local lag coefficient for off-axis positions had not been fully characterized, requiring that results for symmetrically positioned particles (“centerline approximations”) be employed in predicting diffusional and convective hindrances. In this paper the current status of hindered transport theory is reviewed for neutral spheres in long cylindrical pores or slits, and it is shown that such approximations are no longer necessary. N...

Devolatilization of Biomass Fuels and Biomass Components Studied by TG/FTIR Technique

Abstract: Biomass fuels represent a renewable energy source, they are CO2 neutral fuels, and their use reduces the consumption of fossil fuels and limits the emissions of SOx, NOx, and heavy metals. They are...

Photocatalytic Process for CO2 Emission Reduction from Industrial Flue Gas Streams

Abstract: At present, carbon dioxide (CO2) is the largest contributor among greenhouse gases. This article addresses the potential application of photocatalysis to the reduction of CO2 emissions from industr...

Sigma-Profile Database for Using COSMO-Based Thermodynamic Methods

Abstract: Thermodynamic methods based on conductor-like screening models (COSMO) originated from the use of solvation thermodynamics and computational quantum mechanics. These methods rely on sigma profiles specific to each molecule. A sigma profile is the probability distribution of a molecular surface segment having a specific charge density. Two COSMO-based thermodynamic models are COSMO-RS (realistic solvation) developed by Klamt and his colleagues, and COSMO-SAC (segment activity coefficient) published by Lin and Sandler. Quantum mechanical calculations for generating the sigma profiles represent the most time-consuming and computationally expensive aspect of using COSMO-based methods. A growing number of scientists and engineers are interested in the COSMO-based thermodynamic models but are intimidated by the complexity of performing quantum mechanical calculations. This paper presents the first free, web-based sigma profile database of 1432 compounds. We describe the procedure for sigma profile generation, and we have validated our database by comparing COSMO-based predictions of activity coefficients, normal boiling point and solubility with experimental data and thermodynamic property database. We discuss improvements which include using supplemental geometry optimization software packages to provide good initial guesses for molecular conformations as a precursor to the COSMO calculation. Finally, this paper provides a FORTRAN program and a procedure to generate additional sigma profiles, as well as a FORTRAN program to generate binary phase-equilibrium predictions using the COSMO-SAC model. Our sigma profile database will facilitate predictions of thermodynamic properties and phase behaviors from COSMO-based thermodynamic models.

Effect of Curing Temperature and Silicate Concentration on Fly-Ash-Based Geopolymerization

Abstract: The development of the pore structure of geopolymers synthesized from class F fly ash was studied using electron microscopy and porosimetry. Fly-ash-based geopolymer can be classified as a mesoporous aluminosilicate material, with a Si/Al composition varying from 1.51 to 2.24. The Si/Al composition and pore structure of fly-ash-based geopolymer vary depending on the curing temperature and the silicate ratio of the activating solutions (SiO2/M2O, M = Na or K). A higher Si/Al ratio and finer pores are obtained in geopolymers synthesized at higher temperature and silicate ratios. Elevating the curing temperature increases the extent and rate of reaction, shown through an increase in mesopore volume, surface area, and an accelerated setting time. The kinetics appears to be temperature-controlled only before the material is hardened. Very high silicate ratios (SiO2/M2O ≥ 2.0) are also believed to slow the reactions. The pore structure of K-based geopolymer is more susceptible to change in temperature than that...

Effect of Preparation Temperature on Cyclic CO2 Capture and Multiple Carbonation−Calcination Cycles for a New Ca-Based CO2 Sorbent

Abstract: The cyclic CO2 capture, transient phases change, and microstructure appearance of a new kind of Ca-based regenerable CO2 sorbent, CaO/Ca12Al14O33, obtained by the integration of CaO as solid reactant with a composite metal oxide of Ca12Al14O33 as a binder, were investigated by thermogravimetric analysis, XRD, and SEM at different preparation calcination temperatures. When the calcination temperature in the preparation stage is higher than 1000 °C, the cyclic CO2 capture of this new sorbent declines. The lowered CO2 capture may mainly be attributed to the formation of Ca3Al2O6, which decreases the ratio of CaO to binder in sorbent, and the severe sintering of sorbent occurs when calcined at such high temperatures in the preparation processes. These results suggest that the calcination temperature for this new sorbent should not be higher than 1000 °C in order to obtain its high reactivity. The performance of the new sorbent over 50 cycles was evaluated under mild and severe regeneration conditions, respect...

Calcium Oxide Based Sorbents for Capture of Carbon Dioxide at High Temperatures

Abstract: Calcium oxide is a promising sorbent for the capture of carbon dioxide. In this work, CaO sorbents were prepared using different precursors, including Ca(NO3)2·4H2O, CaO, Ca(OH)2, CaCO3, and Ca(CH3COO)2·H2O. Of these, the sorbent prepared from calcium acetate (CaAc2−CaO) resulted in the best uptake characteristics for CO2. This sorbent had a higher BET surface area and larger pore volume than the other sorbents. According to SEM images, this sorbent exhibits a “fluffy” structure, which probably contributes to its high surface area and large pore volume. This sorbent also showed almost 100% carbonation, at temperatures between 550 and 800 °C. Moreover, the carbonation progressed dominantly during an initial short period. Under numerous carbonation/decarbonation cycles, the CaAc2−CaO sorbent demonstrated the best reversibility, even in the presence of 10 vol % water vapor. During a 27-cycle operation, the sorbent maintained fairly high conversion of 62 mol % at 700 °C. Pore size distribution measurements in...

Chemical Looping Combustion in a 10 kWth Prototype Using a CuO/Al2O3 Oxygen Carrier: Effect of Operating Conditions on Methane Combustion

Abstract: Chemical looping combustion (CLC) currently is an attractive option to decrease the greenhouse gas emissions that affect global warming, because it is a combustion process with inherent CO2 separation and with low energy losses. The CLC concept is based on the transfer of oxygen from the combustion air to fuel by means of an oxygen carrier in the form of a metal oxide. The system consists of two separate but interconnected reactors, normally fluidized-bed type. In the fuel reactor, the oxygen carrier particles react with fuel and generate a gas stream mainly composed of CO2 and H2O. The reduced metal oxide is later transported to the air reactor, where oxygen from the air is transferred to the particles; in this way, one can obtain the original metal oxide ready to be returned to the fuel reactor for a new cycle. In this work, a 10 kWth pilot plant that is composed of two interconnected bubbling fluidized-bed reactors has been designed and built to demonstrate the CLC technology. The prototype was operate...

Energy performance of stripper configurations for CO2 capture by aqueous amines

Abstract: Aqueous absorption/stripping is the state-of-the-art technology for the capture of CO2 from coal-fired power plants. This technology is energy-intensive and has been applied to CO2 removal from natural gas, ammonia, and hydrogen gas streams. Energy requirements can be reduced by the use of a more-reactive solvent, operating the cross exchanger at a lower temperature, optimizing the stripper operation, and using innovative stripper configurations (vacuum and multipressure). This work calculates stripper performance with an algorithm in Aspen Custom Modeler (ACM) that incorporates thermodynamic studies, reaction rate measurements, physical properties, and contactor-specific information for three stripper configurationsa simple stripper operating at 160 kPa, a multipressure stripper operating at three pressures (330/230/160 kPa), and a vacuum stripper (30 kPa) for two solvents: 7m (30 wt %) monoethanolamine (MEA) and 5m K+/2.5m piperazine. The temperature approach is varied from 5 to 10 °C. With some approx...

Basic Research Needs for Design of Adsorptive Gas Separation Processes

Abstract: Separation and purification of multicomponent gas mixtures by adsorption is an established process technology. Adsorptive process design requires accurate data on multicomponent gas adsorption equilibria, kinetics, and heats as input variables. These data often cannot be predicted by using today's models, particularly for complex practical systems where the gas mixtures have adsorbates of different sizes and polarities, and the adsorbent is energetically heterogeneous. There is a large volume of pure gas and some binary gas adsorption equilibrium and kinetic data in the published literature, but multicomponent adsorption data are rare. The data for heats of adsorption are only emerging. There is a desperate need to generate a multicomponent adsorption database for better understanding of the complex phenomenon, for seriously testing existing models, and for development of new models. Two recently developed methods called “isotope exchange technique” and “microcalorimetry for adsorption heats” are recommen...

Removal of zinc(ii) from aqueous solution by purified carbon nanotubes: kinetics and equilibrium studies

Abstract: Single-walled carbon nanotubes (SWCNTs) and multiwalled carbon nanotubes (MWCNTs) were purified by sodium hypochlorite solutions and were employed as sorbents to study the kinetics and equilibrium of Zn2+ sorption from aqueous solution. The amount of Zn2+ sorbed onto CNTs increased with a rise in temperature. Using the same conditions, the Zn2+ sorption capacity of CNTs was much greater than that of commercially available powdered activated carbon, reflecting that SWCNTs and MWCNTs are effective sorbents. The thermodynamic analysis revealed that the sorption of Zn2+ onto CNTs is endothermic and spontaneous. The sorption/desorption study showed that the Zn2+ ions could be easily removed from the surface site of SWCNTs and MWCNTs by a 0.1 mol/L nitric acid solution and the sorption capacity was maintained after 10 cycles of the sorption/desorption process. This suggests that both CNTs can be reused through many cycles of water treatment and regeneration.

Layered Double Hydroxides for CO2 Capture: Structure Evolution and Regeneration

Abstract: Mg-Al-CO3 layered double hydroxide (LDH) was synthesized, and its thermal evolution was investigated using X-ray diffraction, FTIR spectroscopy, and thermogravimetric analysis ( TGA). The resultant LDH derivatives showed excellent CO2 adsorption capabilities, especially suitable for high- temperature CO2 separation from flue gases. Calcination of crystalline LDHs at 400 degrees C led to phase transformation yielding amorphous Mg- Al mixed oxides having a CO2 sorption capacity of 0.49 mmol/ g at 200 C. Reversible and irreversible CO2 sorption was determined to be similar to 88% and similar to 12% of the total CO2 sorption, respectively. Regeneration restored the Mg- Al mixed oxide to 98% of its initial CO2 sorption after several cycles of CO2 adsorption testing. This clearly indicates the desirable properties of Mg- Al mixed oxide for CO2 capture from flue gases at high temperatures ( up to 200 degrees C).

Quantification of Hydroxyl Radicals Produced in Aqueous Phase Pulsed Electrical Discharge Reactors

Abstract: High voltage pulsed electrical discharges in water are of interest for a number of applications, for example, in chemistry, water treatment, electrical transmission, and bioengineering, because of the formation of highly reactive molecular and radical species (including the hydroxyl radical). While the existence of hydroxyl radicals in these systems has been demonstrated by emission spectroscopy, accurate quantification of the rates of formation of this species is needed to develop insight into the means by which electrical discharge can promote useful chemical reactions. This paper focuses on quantification of hydroxyl radicals using chemical probes (dimethyl sulfoxide (DMSO) and disodium salt of terephthalic acid (NaTA)).

Development of a Detailed Gasoline Composition-Based Octane Model

Abstract: We present a model that predicts the research and motor octane numbers of a wide variety of gasoline process streams and their blends including oxygenates based on detailed composition. The octane number is correlated to a total of 57 hydrocarbon lumps measured by gas chromatography. The model is applicable to any gasoline fuel regardless of the refining process it originates from. It is based on the analysis of 1471 gasoline fuels from different naphtha process streams such as reformates, cat-naphthas, alkylates, isomerates, straight runs, and various hydroprocessed naphthas. Blends of these individual process streams are also considered in this work. The model predicts the octane number within a standard error of 1 number for both the research and motor octane numbers.

Bulk-fluid solubility and membrane feasibility of rmim-based room-temperature ionic liquids

Abstract: This paper shows how gas solubility can be predicted in Rmim-based room-temperature ionic liquids (RTILs). We have developed a model to illustrate that ideal, single-gas solubility in Rmim-based RTILs is primarily a function of molar volume of the RTIL. This method is used to estimate bulk-fluid gas solubility, showing that for Rmim-based RTILs there is a particular molar volume where a maximum amount of gas per volume of RTIL occurs at a given pressure and temperature. This method is also used to estimate gas permeability and gas pair separation selectivity for ideal CO2/N2 and CO2/CH4 separations. A comparison to traditional polymer membranes utilized in these separations is included in the form of a “Robeson plot”.