Hydrocarbon Functional Groups Research Articles

Reaction heat effect and change characteristics of key groups in coal-oxygen intrinsic reaction path.

The intrinsic reaction of coal with oxygen in the process of low-temperature oxidation is the main reaction path leading to self-heating and spontaneous combustion of coal. Most of the existing studies regard the coal oxidation as an overall reaction, ignoring the multi-path characteristics of coal low-temperature oxidation, and it is difficult to accurately explore the intrinsic reaction characteristics between coal with oxygen. Therefore, the low-temperature oxidation process of coal was studied by using a C80 microcalorimeter and in situ FTIR technology from the macro and micro levels. The "profile subtraction method" was used to study the coal-oxygen intrinsic reaction process, and the reaction heat effect and the change characteristics of key functional groups in the process were analyzed. Furthermore, the gray correlation analysis method was used to study the relevant characteristic parameters in the reaction process and grasp the essential structure-activity relationship. The experimental results show that, compared with the overall reaction process in air atmosphere, the change in the heat release of the coal-oxygen intrinsic reaction path has changed to different degrees, and the change in the slow oxidation stage is the most significant (the heat absorption decreases by 70.1-90.9%). In addition, the characteristic temperature points show different degrees of advance, of which the initial exothermic temperature point is the largest (about 21-46 °C), which directly leads to a significant shortening of the slow oxidation stage (30.1-47.4%). The changes of functional groups in the intrinsic reaction path are more regular. With the increase of temperature, the oxygen-containing functional groups -C=O and the aliphatic hydrocarbon functional groups -CH2- and -CH3 showed a fluctuating trend of increasing and decreasing, respectively. The oxidation heat-contributing functional groups of coal are mainly related to the degree of metamorphism and the functional group reaction characteristics during the reaction. With the deepening of coalification degree, the main heat-contributing functional groups as a whole showed the change rule of oxygen-containing functional groups → aliphatic hydrocarbon functional groups → aromatic hydrocarbon functional groups. In addition, the change of -OH content in the three coal samples has a high correlation with the change of the total heat release of coal.

Development of infrared-assisted hybrid solar dryer for drying pineapple slices: Investigation of drying characteristics, mass transfer parameters, and quality attributes

The research aims to the development and performance evaluation of an infrared-assisted hybrid solar dryer (IR-HSD) for drying pineapple slices. The IR-HSD contains an evacuated tube solar collector, blower assembly, drying chamber, infrared heater, phase change material (PCM) chamber, etc. The study investigates and compares the thermal profiling, drying kinetics, mass transfer parameters and quality attributes of pineapple slices dried using different methods, such as direct drying, phase change material (PCM)-assisted drying, PCM + IR-assisted drying, and sun drying. The average temperatures achieved inside the drying chamber for direct drying and PCM-assisted drying were 60.16 °C and 57.29 °C, respectively, while the temperature reached 60 °C for PCM + IR assisted drying. The average drying rate in PCM + IR drying was higher than in direct and PCM-assisted drying methods. The best-fitting models were the Modified Page model for direct and PCM + IR-assisted drying and the Midilli-Kucuk model for PCM-assisted and sun drying. The higher effective moisture diffusivity for PCM + IR-assisted drying was 2.59 × 10−9 m2/s, followed by direct and PCM-assisted drying. Similarly, the convective mass transfer coefficient obtained was 1.085 × 10−7 m/s, 8.321 × 10−8 m/s, and 1.381 × 10−7 m/s for direct, PCM-assisted, and PCM + IR-assisted drying, respectively. The superior quality attributes such as total flavonoid content (TFC), total phenolic content (TPC), and antioxidant activity were observed in all drying approaches with retention of colour except open sun drying, which decreased significantly. FTIR spectroscopy analysis confirmed the presence of different bioactive, including aromatic compounds, phenols and hydrocarbon functional groups. The infrared-assisted hybrid solar drying of pineapple slices showed a better drying process and quality attributes.

Characteristics and mechanism of Glutathione in inhibiting coal spontaneous combustion

Inhibitors play an important role in preventing and controlling coal spontaneous combustion (CSC). In this study, the inhibitory effects of antioxidant-reduced glutathione (G-SH) on CSC were examined. Thermogravimetric-differential scanning calorimetry (TG-DSC), cross-point temperature (CPT), and oxidation product tests were used to examine the effect of G-SH on the tendency of CSC and compare the discrepancy in the inhibition effect of G-SH and the halogen inhibitor. The changes in the free radical type, concentration, and surface functional groups in coal before and after the addition of G-SH were analyzed using electron spin resonance spectroscopy (ESR) and Fourier transform infrared spectroscopy (FT-IR). Six common active radical models were constructed, and the thermodynamic parameters of the reaction were calculated using density functional theory (DFT). The results revealed that G-SH inhibits the spontaneous combustion of coal. The inhibitory effect of G-SH was significantly stronger than that of the halogen salt inhibitors CaCl2 and MgCl2, and the higher the concentration of G-SH, the stronger is the inhibitory effect. The characteristic temperature points in the thermogravimetric experiment of coal samples with G-SH shifted to a higher temperature zone, and the CO concentration and oxygen consumption were lower than those of raw coal. After G-SH treatment, the type and relative concentration of free radicals in coal were lower than those in raw coal, the content of aliphatic hydrocarbon functional groups and oxygen-containing functional groups decreased, and the content of sulfur-containing functional groups increased. According to the calculation of Gibbs free energy and reaction enthalpy, G-SH can effectively neutralize the active free radicals in the process of coal oxidation, and the reaction activity with the free radicals in the process of coal oxidation is ·OOH > ·OH > ·CH3 > RO· > R· > ROO·. According to the experimental results, it is inferred that G-SH continuously supplies a large number of hydrogen donors (·H) for the reaction during the oxidation process and simultaneously neutralizes carbon free radicals and carbon oxygen free radicals, thereby reducing the concentration and reactivity of free radicals in the whole chain reaction process and blocking the occurrence of coal-oxygen composite reaction.

Spontaneous Combustion Characteristics and Inhibition of Air-Dried Coal with Varying Water Soaking Times

ABSTRACT Coal left in the goaf is prone to oxidation reactions when soaked in water and air-dried, which can cause a temperature increase and potentially lead to a mine fire. The spontaneous combustion characteristics of residual coal soaked in the goaf differ significantly from those of dry coal. Analyzing the variation rules of functional groups in coals with different water soaking times (WSTs) during low-temperature oxidation and exploring the inhibitory effect of an inhibitor on coals with different WSTs are vital in preventing and controlling fires in soaked and air-dried coal seams in the goaf. This paper analyzes the variation rules of functional groups in raw coal samples and samples soaked for one, three, and five months, as well as the corresponding samples under the influence of the inhibitor, MgCl2, using an experimental system of coal low-temperature oxidation and a Fourier transform infrared spectrometer. The following findings were obtained: as the WST increases, the aliphatic hydrocarbon content increases, the low-temperature oxidation activity becomes higher, and the inhibition effect of the inhibitor weakens gradually. As the WST increases, the -CH2, -CH3, -OH, and -COOH contents fall gradually, while the C=O content rises. At the beginning of the oxidation temperature rise (30–70°C), the inhibitor, MgCl2, slows down the consumption of oxygen-containing functional groups and aliphatic hydrocarbon functional groups. However, when the temperature exceeds 130°C, its inhibitory effect on coal oxidation weakens gradually. In this case, a growing number of functional groups are involved in coal oxidation, and the inhibitor fails to effectively prevent coal oxidation. Therefore, it is necessary to strengthen temperature monitoring in the goaf and regularly replenish inhibitors in soaked and air-dried coal seams to enhance the inhibitory effect and prevent the SC of such seams.

Effects of thermal aging atmospheres on oxidation activity, element composition and microstructure of diesel soot particles.

As an emission control device for diesel engines, DPF plays an important role in reducing particulate matter emissions. The research work on soot thermal aging will help optimize DPF regeneration strategies, improve regeneration efficiency, and promote the progress of engine emission control technology. In order to explore the influence of thermal aging under different atmospheres on particle physicochemical characteristics from diesel engines, the oxidation activity of soot particles after different thermal aging were evaluated by thermogravimetric analysis (TGA) and pyrolysis kinetics calculation, and the distribution of functional groups and elemental composition on the soot surface were investigated by FT-IR and XPS analysis. Additionally, the microstructure and graphitization degree of basic carbon with O2/NO2 aging were analyzed by HRTEM technology. The results show that the ignition temperature and activation energy of soot significantly increase after thermal aging, and their lowest values are 569 °C and 165.29 kJ mol-1 in O2/NO2/N2 atmosphere, respectively. The branching degree and content of hydrocarbon functional groups on the soot surface decrease after thermal aging, and the relative content of hydrocarbon functional groups with NO2 participating in thermal aging is the highest. The content of O element on the soot surface decreases after thermal aging, and the maximum O/C molar ratio of soot particles after thermal aging in O2/NO2/N2 atmosphere is 0.15. After thermal aging, the hybridization degree of carbon atoms and the content of -C-OH and -C[double bond, length as m-dash]O functional groups on the soot surface decrease. The content of -C-OH functional group decreases to 0.21% and 0.53% respectively after the addition of O2 and NO2 in the thermal aging atmosphere, while the content of -C[double bond, length as m-dash]O functional group increases to 4.98% and 5.98% respectively. In addition, the layer spacing and microcrystalline curvature of basic carbon particles decrease after thermal aging, however, the microcrystalline size and the graphitization degree increase.

Effects of palm oil biodiesel addition on exhaust emissions and particle physicochemical characteristics of a common-rail diesel engine

In this study, the effects of varying diesel/biodiesel blending ratios on exhaust emissions and particle physicochemical characteristics were conducted on a four-cylinder high-pressure common-rail diesel engine. The experiment involved the application of reference diesel (B0) and several diesel/biodiesel blends (B20, B50, B70 and B100) as the alternative fuels for diesel engine. The results indicated that the addition of biodiesel resulted in a significant reduction of HC, CO and soot emissions except for NOx, the generation of soot precursors such as polycyclic aromatic hydrocarbons (PAHs), ethylene and acetylene were inhibited, and the unregulated emissions of formaldehyde and acetaldehyde increased slightly, while they still were <45 ppm. At rated load, the soot and PAHs emissions of B70 fuel decreased by 28% and 24%, respectively. With the increase of biodiesel blending ratio, the molar and mass ratios of O/C, aliphatic hydrocarbon functional groups (CH) and oxygen-containing functional groups (-OH and -C=O), as well as the degree of disorder (sp3/sp2) on soot surface increased. Furthermore, the initial oxidation temperature and burnout temperature of B20, B50 and B70 soot samples were lower than those of B0 soot samples, and their apparent activation energy decreased by 4.67%, 9.76% and 17.09%, respectively.

Depositional Environment and Hydrocarbon Distribution in the Silurian–Devonian Black Shales of Western Peninsular Malaysia Using Spectroscopic Characterization

The present study aimed to evaluate the hydrocarbon functional groups, aromaticity degree, and depositional environment in the Silurian–Devonian Kroh black shales of western peninsular Malaysia. Fourier transform infrared spectroscopy (FTIR) was applied to measure the hydrocarbon functional groups in the sedimentary succession and associated organic matter of the black shale samples. The results showed that aromatic C=C stretching, aromatic C-H out-of-plane, aromatic C-H in-plane, and aliphatic =C–H bending are the major hydrocarbon functional groups in the Kroh shales. Also, ultraviolet-visible spectroscopy (UV-Vis) was used to evaluate the type of humic substance and analyze the sample extract ratios of E4/E6. It was revealed that the methanol-treated Kroh shale samples ranged from 0.00048 to 0.12 for E4 and 0.0040 to 0.99 for E6. The lower E4/E6 ratio (&gt;5) indicates the dominance of humic acid over fulvic acid in the Kroh shales. The Kroh shale samples’ total organic carbon content (TOC) ranges from 0.33 to 8.5 wt.%, analyzed by a multi-N/C 3100 TOC/TNb analyzer. The comparison study revealed that the TOC content of the Kroh shale has close obtainable values for the Montney shales of Canada. Furthermore, both hydrocarbon functional groups from FTIR, and the E4/E6 ratio from UV-Vis show no correlation with TOC content. It is revealed that humic acid, aromatic, and aliphatic hydrocarbons are not the controlling factors of the enrichment of organic matter in the Kroh shales. Conversely, a positive correlation between aliphatic and aromatic hydrocarbons in the Kroh shales indicated that organic matter is thermally overmatured. The presence of humic acid and enrichment of aromatic hydrocarbons in the Kroh shales demonstrated that the organic matter in these shales contains plant-derived hydrophilic minerals, i.e., terrestrial in origin. These findings may provide clues on the depositional and thermal maturation of organic matter for the exploration efforts into the pre-Tertiary sedimentary successions of the peninsular.

Structure and reactivity of residual carbon from circulating fluidized bed coal gasification fine ash

Due to the high carbon and ash content of coal gasification fine ash (CGFA) produced by circulating fluidised bed gasifiers, it is mainly dissipated in landfills, resulting in soil and water pollution and energy wastage. The presence of carbon limits the application of CGFA in building materials and ceramics. Large-scale dissipation of CGFA can be achieved if the carbon in CGFA has active oxidation properties and potential as a material for the preparation of carbon. Therefore, exploring the form of carbon present in CGFA is crucial for the resourceful and harmless use of CGFA. Demineralisation of different types of CGFA from a circulating fluidised bed gasifier with a gas production capacity of 40,000 Nm3/h was carried out to obtain demineralised carbon (DC) and to investigate the structure and reactivity of the DC. The d002 and Lc values of the DC increased, the cross-linkage decreased, the main microcrystalline structural parameters of the aromatic carbon network layer with swelling effect increased in the vertical direction, the aromatic carbon and aliphatic hydrocarbon functional groups increased and the oxygen-containing functional groups all tended to decrease to different degrees. Based on the changes of CGFA chemical structure before and after acid treatment, a CGFA chemical structure model was constructed. Through TG experiments and Raman analysis of the samples, the activation energy value of the DC carbon was less than 70 kJ/mol, and the relationship between the carbon structure and combustion reactivity of the Raman characterisation was constructed. The DC had a specific surface area above 350 m2/g and was prepared as activated carbon after KOH and high temperature activation. The activated carbon had a specific surface area of 1636.2211 m2/g, a pore volume of 1.6796 cm3/g and a density of 1 g/cm3. The above indicates that CGFA has the potential to be used as a fuel for combustion, secondary gasification and DC can be used as an adsorbent or a pressed precursors for activated carbon.

Experimental study on coal dust wettability strengthened by surface active ionic liquids.

The water wettability of coal dust was very important for dust control when using water-based dust suppressant materials. The coal dust wettability strengthened by surface active ionic liquid was studied in this paper. The surface activity of ten ionic liquids with different anions Cl-, Br-, [BF4]-, [NTf2]- and cations [HOEtMIm]+, [Cnmim]+ (n = 4, 12, 14, 16) was studied by surface tension test. The water wettability of raw coal dust can be improved individually by adding ionic liquid to water or pre-treating coal dust by ionic liquids. The wettability of lignite was improved little, but that of bituminous coal and anthracite were improved much. The dual strengthened effects of ionic liquids on coal dust wettability were studied by the wetting results between ionic liquids solutions and ionic liquid-treated coal samples. The wettability of lignite can be strengthened under the combined action of [HOEtMIm][NTf2] and [C12MIm]Br, while other dual effects were not satisfactory. All ionic liquids combination had strengthened effects on the wettability of bituminous coal and anthracite, especially the [C12MIm]Br treatment and [C12MIm]Br solutions together had the best dual effects. The functional groups results indicated that the hydrophilic oxygen-containing functional groups in treated coal samples increased, the hydrophobic aliphatic hydrocarbon functional groups decreased and part of ionic liquids were adsorbed on the coal surface. These changes together enhanced the wettability of coal with high coalification degrees.

Karakteristik Komposit Bioplastik Maizena dan Glukomanan pada Perlakuan Jenis dan Konsentrasi Bahan Pengisi

This study aims to know the effect of the type and concentration of filler on the characteristics of cornstarch and glucomannan bioplastic composites, and determine the type and concentration of fillers that can produce bioplastic composites that meet the Indonesian National Standard (SNI) and International Standard. This study used a randomized block design with two factors. Factor I is a type of filler consisting of ZnO, CaCO3, clay, nanocellulose. Factor II is the concentration of filler which consists of 4 levels, namely 0%; 5%; 10%; 15%. This experiment resulted in 16 treatment combinations and were grouped into 2 groups so that 32 experimental units were obtained. The data were analyzed for diversity and continued with the Tukey test using Minitab17 software. The results showed that the type and concentration of filler had a very significant effect on tensile strength, elongation, modulus young, swelling, biodegradation and had a significant effect on WVTR. The interaction has a very significant effect on tensile strength, modulus young, swelling, WVTR and has a significant effect on elongation and biodegradation. Cornstarch and glucomannan bioplastic composites that meet the Indonesian National Standard (SNI) and International Standard on tensile strength and biodegradation variables using nanocellulose fillers with concentrations of 10% and 15% which have tensile strength characteristics of 15,23 and 16,93 MPa, elongation at break of 11,47 and 10,76 %, modulus young of 132,81 and 158,61 MPa, swelling of 68,93 and 69,58 %, WVTR 1,18 and 1,24 g/m2.hr, biodegradation rate for a long time 7 days. Maizene and glucomannan bioplastic composites contain hydrocarbon functional groups -(CH2)n, carboxyl (C-O), alkene (C=C), alkyne (C?C), hydroxyl carboxylic acid (O-H), hydroxyl alcohol (O-H), carbonyl (C=O) and aromatic compounds (C-H).&#x0D; Keywords: bioplastic composite, cornstarch, glucomannan, ZnO, CaCO3, clay, nanocellulose

Identification and Quantification of Hydrocarbon Functional Groups in Gasoline Using 1H-NMR Spectroscopy for Property Prediction.

Gasoline is one of the most important distillate fuels obtained from crude refining; it is mainly used as an automotive fuel to propel spark-ignited (SI) engines. It is a complex hydrocarbon fuel that is known to possess several hundred individual molecules of varying sizes and chemical classes. These large numbers of individual molecules can be assembled into a finite set of molecular moieties or functional groups that can independently represent the chemical composition. Identification and quantification of groups enables the prediction of many fuel properties that otherwise may be difficult and expensive to measure experimentally. In the present work, high resolution 1H nuclear magnetic resonance (NMR) spectroscopy, an advanced structure elucidation technique, was employed for the molecular characterization of a gasoline sample in order to analyze the functional groups. The chemical composition of the gasoline sample was then expressed using six hydrocarbon functional groups, as follows: paraffinic groups (CH, CH2 and CH3), naphthenic CH-CH2 groups and aromatic C-CH groups. The obtained functional groups were then used to predict a number of fuel properties, including research octane number (RON), motor octane number (MON), derived cetane number (DCN), threshold sooting index (TSI) and yield sooting index (YSI).

Effect of coal particle density on coal properties and combustion characteristics

In the present work, the combustion characteristics of coal particles with varying average specific gravity (ASG) have been reported. Proximate analysis, ultimate analysis, GCV, petrographic analysis and FTIR analysis were carried out to identify variation in coal properties with varying ASG of coal from1.24 to 1.9. Burning profile parameters and combustion indices are evaluated from TGA analysis. Experimental results inferred that with the increase in coal ASG from 1.24 to 1.9 GCV decreased from 7266 kcal/kg to 3741 kcal/kg, heat release rate varied between 1386 kcal/min to 120 kcal/min, burning time increased from 9 to 30 min and vitrinite varied from 58% to 2.5%, liptinite varied from 13.5% to 1.5%, inertinite varied from 19.2% to 65.7%. Differences in the combustion properties were correlated with hydrocarbon functional groups obtained from FTIR analysis and macerals composition further exploration in details with varying ASG of coal.

Synthesis of Rhamnolipid Derivatives Containing Ester Isosteres.

Rhamnolipids are biosurfactants with many applications, arising from their inherent biological activity and their potential as bioremediation agents. Herein, we report the synthesis of four rhamnolipid derivatives in which the ester linkage connecting the two lipid chains in the natural compound is replaced with amide, ketone, ether, or hydrocarbon functional groups. Such compounds are anticipated to have enhanced hydrolytic stability and thus be useful probes of rhamnolipid-mediated biology and biotechnology.

Phenomenological soot modeling with solution mapping optimization of biodiesel-diesel blends in diesel engines

It is widely accepted that the particulate matter emissions of a diesel engine may be substantially reduced when a blend of diesel and biodiesel fuels is used. Here we propose a phenomenological model aimed at evaluating the extent of soot formation and oxidation in a diesel engine fueled with diesel–biodiesel blends and providing a better understanding of these processes. These blends are represented by three hydrocarbon functional groups: aromatic, aliphatic, and ester fuels, in different proportions.In a previous study, the phenomenological soot model of Foster and Reitz and colleagues was modified to capture the influence of the diesel–biodiesel molecular composition on soot formation and emissions. In the present work, this model was implemented in computational fluid dynamics (CFD) diesel engine combustion simulations. These CFD simulations were performed using the finite volume method commercial code ANSYS Fluent 16.1. The solution mapping optimization method developed by Frenklach and colleagues was used to calibrate this model for the engine. Validation was performed by comparing the following simulated variables with experimental results: pressure, heat release rate, averaged soot density inside the piston bowl, maximal temperature inside the piston bowl, and exhaust soot emissions. Reasonable agreement was obtained between our computational results and the published experimental results of Mancaruso and colleagues. The soot evolution in the piston bowl in these simulations was to a certain extent qualitatively and quantitatively similar to that in the experiments. The maximal experimental in-cylinder two-color soot density was 44 g/m3 and its computational equivalent was 60 g/m3. The maximal space-averaged two-color soot densities in the experiments and the computations were 9.3 and 7.73, respectively. The experimental soot reduction potentials of biodiesel blending for B20, B50, and biodiesel were 12.0%, 27.3%, and 47.2%, respectively. The respective computational soot reduction potentials were 34.8%, 36.2%, and 43.4%.

Theoretical study of hydrocarbon functional groups on elemental mercury adsorption on carbonaceous surface

The interaction between Hg0 and carbonaceous surface containing hydrocarbon functional groups (HFG) is investigated by DFT calculations. The carbonaceous surface is represented by a cluster model consisting of nine fused benzene rings. HFG is expressed by the molecular formulas of CxHy (x = 1, 2; y = 1, 2, 3…6). All possible approaches of HFG are carried out to evaluate the effect on mercury adsorption. The results indicate that the adsorption of HFG can increase the activity of its neighboring carbon atoms. In addition, the number of carbon atoms and hydrogen atoms on HFG has great influence on adsorption characteristics. The effect of HFG on Hg0 adsorption on a carbonaceous surface is complicated. The mercury adsorption property depends on the adsorption position of mercury atom. When mercury atom is adsorbed by both HFG and carbonaceous surface, the mercury adsorption is determined by HFG, carbonaceous surface and carbon ring together. When mercury atom is only adsorbed by carbonaceous surface, the behaviors of neighboring and next-nearest neighboring carbon atoms on carbonaceous surface determine the mercury adsorption.

Structural, optical and photoconductivity studies of ZnO bicones synthesized by seed-mediated method

ZnO bicones (BC) have been synthesized by a seed-mediated method using polyethylene glycol (PEG) and triethylamine (TEA). As-synthesized ZnO BC has been characterized by X-ray diffraction method (XRD), UV–visible absorption spectroscopy, Photoluminescence spectroscopy (PL), Fourier Transform Infrared (FTIR) spectroscopy, Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM) and Time-dependent Photoconductivity study. XRD pattern of ZnO BC shows hexagonal wurtzite phase structure. The UV–visible absorption spectrum of ZnO BC shows two absorption band edges at 302 nm and 370 nm due to its diameter and length. The PL spectrum of ZnO BC shows rich zinc interstitial defects due to the presence of an intense peak at 423 nm. The FTIR spectrum of ZnO BC confirms the presence of TEA and PEG. SEM and TEM images of ZnO nanostructures confirm the bicones structure as well as the size of the ZnO BC. Photoconductivity study shows that the time-dependent rise and decay curves of ZnO BC has very high photosensitivity in vacuum medium compared to its air medium due to the presence of hydrocarbon functional groups and oxygen deficiency atmosphere.

Thermal effects and active group differentiation of low-rank coal during low-temperature oxidation under vacuum drying after water immersion

Reasons for the more spontaneous combustion of coal in the goaf after being immersed were investigated. Using simultaneous thermal analysis, heat flow and thermal mass curves with temperature were measured for two low-rank raw and water-immersed coals, obtained from the Xinjiang and Pingshuo regions of China, with different water contents after air drying. The influence of water content on the low-temperature oxidation and exothermic characteristics of coal during the process of immersion and air drying was analyzed. Three-dimensional in situ Fourier Transform infrared spectra, measured during the low-temperature oxidation of water-immersed coal that easily spontaneously combusted and raw coal, enabled comparison and analysis of differences in the initial functional group structures of the two coal samples and their evolution during the oxidation process. The results showed that there is a range of moisture contents experienced during the process of water immersion and air drying that renders the coal more prone to spontaneous combustion than raw coal. Within this range, one specific moisture content was most susceptible to spontaneous combustion. When water-immersed coal was air-dried to the critical moisture content that was most likely to self-ignite, the contents of associated hydroxyl and aliphatic hydrocarbon functional groups were larger than those of the raw coal. The oxidation reaction rates of these two groups were accelerated. These changes promote the rapid formation of aliphatic chain cyclic reactions and increase the initial heat release, resulting in such coal being more spontaneously combustible.

Spatial Distribution of Total Petroleum Hydrocarbon (TPH) in Sediment of Sumba Sea, Nusa Tenggara Timur

Sumba Sea is an Indo-Australian tectonic plate transition zone that has a huge biodiversities resources and also behalf of an international shipping lane zone from southern of Indonesia to Australia and New Zealand, and as the return. In addition, Sumba Sea is also a kind of outer boundary of Indonesia, that is necessary to do basic environmental monitoring as the authorities in the management of outer sea zone. Indonesia does not have representative environmental quality database including the pollution of Total Petroleum Hydrocarbons (TPH). This study purposes to determine the partial distribution and concentration of TPH in sediments in Sumba Sea, East Nusa Tenggara. The research was conducted in August 2016 using Research Vessel of Baruna Jaya VIII. Samples were collected using a box core, preserved in amber glass jar bottle and stored at 4°C for further analysis in the laboratory. In the laboratory, sediment samples were extracted using dichloromethane and n-hexane for three times extraction. Furthermore, samples were evaporated before added by tetrachloroethylene solvent. Samples were measured with Fourier Transform Infra Red (FTIR) at wavelength 2850-2950 cm&lt;sup&gt;-1&lt;/sup&gt;. The results showed that the pollution of Total Petroleum Hydrocarbon (TPH) in the Sumba Sea was detected at all sampling station based on identified of hydrocarbon functional groups. The partial distribution of TPH is evenly distributed and covered all stations on low concentrations. The highest concentration of TPH was detected at station 10 as 4.348 ppm

Industrial waste-heat recovery through integrated computer-aided working-fluid and ORC system optimisation using SAFT-[formula omitted] Mie

A mixed-integer non-linear programming optimisation framework is formulated and developed that combines a molecular-based, group-contribution equation of state, SAFT-γ Mie, with a thermodynamic description of an organic Rankine cycle (ORC) power system. In this framework, a set of working fluids is described by its constituent functional groups (e.g., since we are focussing here on hydrocarbons: CH3, CH2, etc.), and integer optimisation variables are introduced in the description the working-fluid structure. Molecular feasibility constraints are then defined to ensure all feasible working-fluid candidates can be found. This optimisation framework facilitates combining the computer-aided molecular design of the working fluid with the power-system optimisation into a single framework, thus removing subjective and pre-emptive screening criteria, and simultaneously moving towards the next generation of tailored working fluids and optimised systems for waste-heat recovery applications. SAFT-γ Mie has not been previously employed in such a framework. The optimisation framework, which is based here on hydrocarbon functional groups, is first validated against an alternative formulation that uses (pseudo-experimental) thermodynamic property predictions from REFPROP, and against an optimisation study taken from the literature. The framework is then applied to three industrial waste-heat recovery applications. It is found that simple molecules, such as propane and propene, are the optimal ORC working fluids for a low-grade (150°C) heat source, whilst molecules with increasing molecular complexity are favoured at higher temperatures. Specifically, 2-alkenes emerge as the optimal working fluids for medium- and higher-grade heat-sources in the 250–350°C temperature range. Ultimately, the results demonstrate the potential of this framework to drive the search for the next generation of ORC systems, and to provide meaningful insights into identifying the working fluids that represent the optimal choices for targeted applications. Finally, the effects of the working-fluid structure on the expander and pump are investigated, and the suitability of group-contribution methods for evaluating the transport properties of hydrocarbon working-fluids are considered, in the context of performing complete thermoeconomic evaluations of these systems.

Biodegradation of petroleum hydrocarbon functional groups in contaminated water using selected protozoan isolates

Diverse microorganisms are responsible for the biodegradation of various petroleum hydrocarbon chains which are found in both the environment and several existing water sources. Most of these microorganisms are both prokaryotic and eukaryotic in nature. The aim of this study was to investigate the degradation of petroleum hydrocarbon functional groups in contaminated water using individual protozoan species (Aspidisca sp., Trachelophyllum sp. and Peranema sp.) as well as a consortium of these three protozoan species. Chemical oxygen demand (COD) and dissolved oxygen (DO) were analysed using standard methods. The concentration of petroleum oil was determined in triplicate before and after the inoculation of oily wastewaters with the abovementioned protozoan species using the partition-gravimetric method. Various functional groups that had been biodegraded by the protozoan isolates were analysed using thin-layer chromatography (TLC) and GC×GC-FID. Results showed an increase in protozoan biomass from an initial cell count of 1.0×103cells/mL to a final cell count of 2.4×103cells/mL for the consortium of isolates, unlike a minimal biomass increases observed with individual isolates over the study period. The average uptake of DO was found to be low at 0.50mg/L from an initial concentration of 6.46mg/L to the final concentration of 6.00mg/L; however, the concentration of COD released by the isolates was found to be in an average range of ≤2300mg/L. The consortium of three isolates was able to biodegrade ≥80% of the hydrocarbon fractions, and aliphatic groups such as short-chain alkanes, alcohol/ester compounds and partially aromatic hydrocarbons were biodegraded, while the individual isolates were able to biodegrade an average of 72% of the amount of petroleum hydrocarbon fractions during the study.