Trace elements in brown coal and its products of combustion

Concentrations of 38 elements in brown coal, bottom ash and size fractionated ESP coal ash from the Belchatów I Power Plant were determined by INAA. Based on enrichment factors calculated relatively to iron and average crustal rock composition as a function of particle size the elements are grouped into three classes: Group I, elements that show little or no enrichment in the small particles /Na, Mg, Al, K, Sc, Ti, Mn, Co, Rb, Cs, Ba, La, Ce, Sm, Eu, Lu, and Th/; Group II, elements whose enrichment increases greatly with decreasing particle size /Cl, Zn, As, Se, Br, Cd, Sb, and I/; and Group III, elements whose behaviour is intermediate to that of elements in Group I and II /Ca, V, Cr, Ni, Cu, Ga, Sr, Mo, In, W, and Au/.     

Experimental study on interaction and kinetic characteristics during combustion of blended coals

The combustion behaviors and kinetic parameters of three parent coals (A1, A2, and A3) and their blends (A1/A2 and A2/A3) have been evaluated under oxidizing atmosphere (O₂ and N₂ mixtures), using a non-isothermal thermo-gravimetric analyzer. The aim of this study is to investigate the interaction between the blended components during the process of co-combustion, and the effects of blending ratio and oxygen concentration (10, 15, and 21%) on combustion performance of blended coals. When high reactivity and low reactivity coals are co-combusted, double peaks are observed in the DTG curves, and significant interaction occurs in the temperature range between the two peaks (T _p1 and T _p2). The activation energies obtained by Coats–Redfern method indicate that the activation energies of blended coals are lower than that of parent coals. The combustibility index S is used to evaluate the combustion performance of blended coals, and the results show the non-additive effects of the combustion characteristics of blended coals. The increased oxygen concentration results in a significant improvement of combustion performance of blended coals. In addition, as the blending ratio of high reactivity coal is increased, the oxygen can greatly enhance the combustion stability of blended coals.     

Chemical structure and gas products of different rank coals during pyrolysis

Journal of Thermal Analysis and Calorimetry - In this study, three coal samples (long flame coal/LFC, coking coal/CC, and anthracite/AC) from the same coal seam in Huaibei coalfield were simulated...     

Release behaviors of sulfur-containing pollutants during combustion and gasification of coals by TG-MS

Journal of Thermal Analysis and Calorimetry - Sulfur-containing pollutants are released during coal thermal conversion processes and must be controlled to satisfy the requirements of industrial...     

Chlorinated organic compounds evolved during the combustion of blends of refuse-derived fuels and coals

The objective of this study was to examine the possible formation of chlorinated organic compounds during the combustion of blends of refuse derived fuels (RDF) and coal under conditions similar to those of an atmospheric fluidized bed combustion (AFBC) system. A series of experiments were conducted using a TG interfaced to FTIR. Additional experiments using a tube furnace preheated to AFBC operating temperatures were also conducted. The combustion products were cryogenically trapped and analyzed with a GC/MS system. The chlorination of phenols and the condensation reactions of chlorophenols were investigated in this study. A possible mechanism for the formation of chlorinated organic compounds such as dibenzodioxins and dibenzofurans, by chlorination and condensation reactions involving phenols, was proposed.The financial support for this work received from the U.S. Department of Energy (Contract No. DE-FG22-94PC94211) and from the Huntsman Thermal Analysis Fellowship is gratefully acknowledged.     

固相萃取采样和气相色谱-质谱检测液化石油气中的芳烃杂质（英文）

建立石墨化碳(GCB)为吸附剂的动态采样系统,可实现液化石油气(LPG)中芳烃杂质的采样和同步萃取富集。LPG中的芳烃杂质(苯、甲苯、二甲苯、苯乙烯和萘)被快速捕集后,进行气相色谱-质谱(GC-MS)定性定量分析。与C18和苯乙烯二乙烯苯吸附剂(PS-DVB)相比,GCB填充柱对芳烃杂质的萃取效率最高。评价了基于GCB填充柱采样的吸附效率、重现性和贮存稳定性。采样和分析方法对氮气模拟气流中8种芳烃的定量分析线性范围为15~1 000μg/m~3。所开发的方法具有回收率高(92.9%~109.0%)、检出限低(1.0~6.2μg/m~3)、准确性好(相对标准偏差为0.6%~5.8%)和准确度高(标准偏差为0.8%~8.2%)等优点。     

Determination of impurities in pesticides and their degradation products formed during the wine-making process by solid-phase extraction and gas chromatography with detection by electron ionization mass spectrometry. II. Bromopropylate, trichlorphon, parathion-methyl and tebuconazole

The presence of degradation products of bromopropylate, trichlorphon, parathion-methyl and tebuconazole in white and red wines elaborated from musts spiked with commercial formulations of the pesticides was studied. Must and wine were subjected to solid-phase extraction followed by gas chromatography with electron ionization mass spectrometric detection. Alpha-bromophenylphenylmethanol, aminoparathion, acetylaminoparathion-oxon and dichlorvos have been identified as degradation products of bromopropylate, parathion-methyl and trichlorphon in wines, respectively. Moreover, the presence of additives and impurities of the formulations in elaborated wines has also been found.     

Determination of impurities in pesticides and their degradation products formed during the wine-making process by solid-phase extraction and gas chromatography with detection by electron impact mass spectrometry. I. Vinclozoline, procymidone and fenitrothion

The presence of degradation products of vinclozoline, procymidone and fenitrothion, and of impurities from their commercial formulations, was studied in white and red wines elaborated from spiked must. After solid-phase extraction the nature of the residues was established by gas chromatography with mass spectrometric detection. The structures of several degradation products and impurities are discussed and elucidated on the basis of their electron impact spectra. In elaborated wines the concentrations of the degradation products and impurities are lower than those of the original active ingredients. Aminofenitrothion and acetylamino-formyl-fenitrothion-oxon are the main residues of fenitrothion in wine. For dicarboximides, an alcohol derivative of vinclozoline was found in addition to 3,5-dichloroaniline.     

Regularities in gas formation at γ-radiolysis of coals and petroleum residues

The regularities of H₂, CO, and CH₄ formation at -radiolysis of brown coals, hard coal, petroleum-bituminous rock, petroleum bitumen, tar, and petroleum residue have been studied at room temperature, absorbed radiation dose 30–2400 kGy, dose intensity 1.6–21.1 kGy/h. The radiation-chemical yields of these gases were found to constitute °G^r0.005–0.07 mol/100 eV for coals, and °G^r0.3–0.6 mol/100 eV for petroleum residues.     

Determination of vanadium in petroleum and petroleum products using atomic spectrometric techniques

Vanadium is recognized worldwide as the most abundant metallic constituent in petroleum. It is causing undesired side effects in the refining process, and corrosion in oil-fired power plants. Consequently, it is the most widely determined metal in petroleum and its derivatives. This paper offers a critical review of analytical methods based on atomic spectrometric techniques, particularly flame atomic absorption spectrometry (FAAS), electrothermal atomic absorption spectrometry (ET AAS), inductively coupled plasma optical emission spectrometry (ICP OES), inductively coupled plasma mass spectrometry (ICP-MS). In addition an overview is provided of the sample pretreatment and preparation procedures for vanadium determination in petroleum and petroleum products. Also included are the most recent studies about speciation and fractionation analysis using atomic spectrometric techniques.     

Simultaneous extraction and fate of linear alkylbenzene sulfonates, coconut diethanol amides, nonylphenol ethoxylates and their degradation products in wastewater treatment plants, receiving coastal waters and sediments in the Catalonian area (NE Spain)

A simple, isocratic liquid chromatographic (LC) method using volatile mobile phase constituents for the identification of related substances in erythromycin samples is described. For method development, evaporative light scattering detection (ELSD) was used. An XTerra RP18 column was used at 70 degrees C with a mobile phase consisting of acetonitrile-isopropanol-0.2M ammonium acetate pH 7.0-water (165:105:50:680). Mass spectral data were acquired on an ion trap mass spectrometer equipped with an electrospray interface operated in the positive ion mode. First, a library was created using MS/MS and MS(n) spectra of reference substances available in the laboratory. Using these reference spectra as interpretative templates, eight novel related substances in erythromycin samples were identified: N-demethylerythromycin E, erythromycin E N-oxide, anhydroerythromycin C, N-demethylerythromycin B, anhydro-N-demethylerythromycin A, pseudoerythromycin E enol ether, EF lacking the neutral sugar and EA lacking the neutral sugar.     

Different stability‐indicating chromatographic methods for specific determination of paracetamol,dantrolene sodium,their toxic impurities and degradation products

A well‐known analgesic (paracetamol, PAR) and skeletal muscle relaxant [dantrolene sodium (DNS)] have been analyzed without interference from their toxic impurities and degradation products. The studied PAR impurities are the genotoxic and nephrotoxic p‐amino phenol (PAP) and the hepatotoxic and nephrotoxic chloroacetanilide, while 5‐(4‐nitrophenyl)‐2‐furaldehyde is reported to be a mutagenic and carcinogenic degradation product of DNS. The five studied components were determined and quantified by TLC–densitometric and RP‐HPLC methods. TLC–densitometry (method 1) used TLC silica gel and chloroform–ethyl acetate–acetic acid–triethylamine (7:3:0.5:0.05, by volume) as the mobile phase with UV scanning at 230 nm, while RP‐HPLC (method 2) was based on separation on a C₁₈ column using methanol–water (55:45, v/v pH 3 with aqueous formic acid) as mobile phase at 1 mL/min and detection at 230 nm. The developed methods were used for determination and quantification of the five studied components in different laboratory‐prepared mixtures. The were also applied for analysis of Dantrelax^® compound capsules where no interference among the studied components with each other or from excipients was observed. The methods were validated as per International Conference on Harmonization guidelines, and they compared favorably with the reported ones.     

Thermogravimetric analysis of lignocellulosic and microalgae biomasses and their blends during combustion

Thermogravimetric analysis was used to study and compare the combustion of different blends of corn bioresidues with sunflower, rape and algae bioresidues. Non-isothermal thermogravimetric data were used to obtain the combustion kinetics of these bioresidues. This paper reports on the application of the Vyazovkin and Ozawa–Flynn–Wall isoconversional methods for the evaluation of kinetic parameters (energy activation, pre-exponential factor and order of reaction) for the combustion of the biomasses studied. Differences were found in the TG curves in accordance with the proximate analysis results for the cellulose, hemicellulose and lignin content of biomasses. The activation energy obtained from combustion (E ~ 151.6 kJ mol^?1) was lower than that from the blends (similar values were obtained for corn–sunflower, E ~ 160.5 kJ mol^?1 and corn–rape, E ~ 156.9 kJ mol^?1) whereas the activation energy obtained from the microalgae was higher (E ~ 171.5 kJ mol^?1). Both the Vyazovkin and Ozawa–Flynn–Wall methods yielded similar results.     

Concentrations and distributions of trace and minor elements in Chinese and Canadian coals and ashes

A total of 35 trace and minor elements including some of environmental significance were determined in each of a selection of 15 Chinese and 6 Canadian thermal coals and their ashes by using the SLOWPOKE-2 nuclear reactor facility of the University of Toronto. The concentrations and distributions of these constituents among the coals and their combustion products (viz. ash and volatile matter) are presented together with an interpretation of their significance in relation to the large scale combustion of these coals as thermal fuels in industrialized countries such as China and Canada. The detailed results showed wide variations in trace impurity concentrations (up to a factor of 100 and more) among the coals studied with few large differences between those of Chinese and Canadian origin except that the rare earths, Sc, Th, U, I, and Se were much higher in the former, other halogens, As and Na were lower. Values for elemental enrichment factors (EF) relative to normal crustal abundances indicated that only As(EF=13), Br(5.7), I(16), S(230), Sb(11) and Se(320) were appreciably enriched in coal. During static ashing at 750°C most of the halogens, S and Se were volatilized whereas most other inorganic constituents were highly retained and concentrated in the ash by factors of 6 to 11.     

Carbazoles,phenazines and dibenzofuran in petroleum products; methods of isolation,separation and determination

Alkylindoles, -carbazoles and -phenazines were isolated from a petroleum distillate by adsorption on activated aluminum oxide and desorption with methanol. After removal of methanol and dilution with benzene, the concentrate was extracted with 72% perchloric acid to obtain the alkylindoles and alkylcarbazoles as soluble perchlorates. These compound types were then isolated from the acidic layer by addition of water and extraction with benzene. A concentrate of the benzene extract was separated by gas chromatography into alkylindoles and 6 different carbazoles, the latter being characterized by ultraviolet and mass spectrometric techniques. The carbazoles were determined photometrically with 2-bromo-2-nitroindandione-1,3 reagent and by gas chromatography. Phenazine and several alkylphenazines were isolated from the nitrogen compound concentrate as solid perchlorates, liberated by alkali treatment of their perchlorates, and separated by gas chromatography ; ultraviolet and mass spectra were used for their identification. Dibenzofuran was identified in the residual concetrate after the acid extraction.     

Determination of basic nitrogen-containing polycyclic aromatic compounds (azaarenes) in petroleum and petroleum products

Summary After a selective enrichment including liquid-liquid-partition (dimethylformamide/water/cyclohexane, 9110; DMF/water/benzene, 3710) and ion-exchange chromatography (SP Sephadex C 25), a basic fraction of a crude oil sample was analysed by capillary gas-chromatography. The enrichment procedure results in an azaarene fraction consisting exclusively of nitrogen-containing compounds as confirmed by a comparison of the chromatograms recorded by FID and a nitrogen-specific detector (N-FID). The coefficients of variation for a series of a several times (n=5) repeated analysis of 8 selected azaarenes from an Arabian Light sample were found to be between 4.7 and 6.7%.

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Bestimmung basischer Stickstoff-haltiger polycyclischer aromatischer Verbindungen (Azaarene) in Erdöl und Mineralölprodukten

Zusammenfassung Nach einer selektiven Anreicherung durch Flüssig-Flüssig-Verteilung (Dimethylformamid/ Wasser/Cyclohexan, 9110; DMF/Wasser/Benzol, 3710) und Ionenaustauscher-Chromatographie (SP Sephadex C 25) wurde die basische Fraktion einer Ölprobe capillargas-chromatographisch getrennt. Das Anreicherungsverfahren liefert eine Azaarenfraktion, die ausschließlich aus Stickstoff-haltigen Verbindungen besteht, was durch einen Vergleich der mit dem FID und N-FID registrierten Gas-Chromatogramme gezeigt werden konnte. Die Variationskoeffizienten einer mehrfach wiederholten Probenserie (Arabian Light, n=5) ergab für 8 ausgewählte Azaarene Werte zwischen 4,7 und 6,7%.

     

Thermogravimetric analysis of combustion characteristics and kinetic parameters of pulverized coals in oxy-fuel atmosphere

Temperature programmed combustions (TPC) of Yang-Quan anthracite, Liao-Cheng lean coal and Li-Yan bituminous coal in oxy-fuel atmosphere were conducted in a thermogravimetric analyzer and characteristic parameters were deduced from the TG-DTG curves. The results showed that combustion got harder to progress as the coalification degree increasing. Within range of 40%, effect of heightening O₂ concentration favored the combustion process, but beyond this zone, the effect leveled off. The model-fitting mathematical approach was used to evaluated the kinetic triplet (f (α), E, A) through Coats–Redfern method. The calculation showed that D ₃-Jander was the proper reaction model and the evaluations of E and A validated the experimental results.