Jan T. Andersson

Measurement and prediction of the emission of pollutants from the combustion of coal and biomass in a fixed bed furnace

In many Eastern European countries the emission of pollutants from coal fired domestic and small commercial heating plants is a serious problem. One alternative method to reduce emissions is by burning coal with biomass that is by co-combustion, which would reduce the amount of net CO2 produced, the rate of reduction of coal reserves, and the overall amounts of pollutants. The effects of co-combustion of coal and biomass on the levels of pollutant formation have been studied for a 30 kW domestic boiler. Of particular interest are the emissions of PAH and VOC since it has been shown that these emissions are lowered during co-combustion. The relation between boiler design fuel composition and measured emission profiles for VOC and PAH is discussed in detail. Outputs from modelling of the emissions and devolatilisation characteristics of the fuels have been compared to measured values. Analytical methods have been developed for characterisation of the initial devolatilisation products from both coal and biomass fuels and the relation to modelling is discussed. The fate of these initial devolatilisation products and the effect of boiler design on the formation of PAH and soot in the post combustion zones is addressed.

Time to Say Goodbye to the 16 EPA PAHs? Toward an Up-to-Date Use of PACs for Environmental Purposes

The 16 EPA PAHs have played an exceptionally large role above all in environmental and analytical sciences in the last 40 years, but now there are good reasons to question their utility in many circumstances even though their use is so established and comfortable. Here we review the reasons why the list has been so successful and why sometimes it is seen as less relevant. Three groups of polycyclic aromatic compounds (PAC) are missing: larger and highly relevant PAHs, alkylated PACs, and compounds containing heteroatoms. Attempts to improve the situation for certain matrixes are known and here: (1) an updated list of PAHs (including the 16 EPA PAHs) for the evaluation of the toxicity in the environment (40 EnvPAHs); (2) a list of 23 NSO-heterocyclic compounds and 6 heterocyclic metabolites; and (3) lists of 10 oxy-PAHs and 10 nitro-PAHs are proposed for practical use in the future. A discussion in the scientific community about these lists is invited. Although the state of knowledge has improved dramatically since the introduction of the 16 EPA PAHs in the 1970s, this summary also shows that more research is needed about the toxicity, occurrence in the environment and chemical analysis, particularly of alkylated PAHs, higher molecular weight PAHs and substituted PACs such as amino-PAHs, cyano-PAHs, etc.. We also suggest that a long overdue discussion of an update of regulatory environmental PAH analysis is initiated.

Characterization of Supercomplex Crude Oil Mixtures: What Is Really in There?

Through different windows: One major obstacle in energy research is the complexity and variety of compounds present in crude oil. A study of different ionization methods for mass spectrometry shows that the mass spectrum very strongly depends on which method is used.

Polycyclic aromatic sulfur heterocycles IV. Determination of polycyclic aromatic compounds in a shale oil with the atomic emission detector

Abstract A method for the determination of alkylated benzothiophenes and dibenzothiophenes, napthothiophenes and several other aromatic compounds in a shale oil as an example for a very complex matrix is presented. Fluorinated aromatics were used as internal standards. The isolated aromatic fraction of the shale oil was separated according to the number of aromatic rings. Oxidation of the two-ring compounds led to benzothiophene sulfones which were further separated by liquid chromatography according to the number of side-chain carbon atoms. The three-ring compounds were separated into a sulfur aromatics-free and a sulfur aromatics-containing fraction using palladium chloride/silica gel. The GC stationary phases necessary for the quantification of all compounds of interest are discussed. Quantitative data obtained with an atomic emission detector are given for 22 compounds in the shale oil. Conventional quantification, without the elaborate separations described here, would overestimate the phenanthrene content of the shale oil by ca. 15% and that of dibenzothiophene by nearly 50%.

Bacterial transformations of benzothiophene and methylbenzothiophenes

The abilities of three Pseudomonas strains transform each of the six isomers of methylbenzothiophene was studied. These compounds would not support growth but were biotransformed in a cell suspension of one of the violates and in cultures of the other two isolates while they grew on 1-methylnaphthalene or glucose. Sulfur-containing metabolites were identified by GC/MS and GC/FTIR, and when possible, by comparison with authentic standards. Sulfoxides and sulfones were frequently detected and were the most abundant products from 2- and 3-methylbenzothiophene. Two of the isolates oxidized the methyl groups to carboxylic acids which were abundant products from 3-, 5-, and 6-methylbenzothiophenes

Gas chromatographic retention indices for all C2- and C2-alkylated benzothiophenes and their dioxides on three different stationary phases

Abstract The retention indices for all C 1 - and C 2 -alkylated benzothiophenes and their dioxides were determined on three stationary phases of different polarity: methylphenylsiloxane, polyethylene glycol and cyanopropylsiloxane. In many instances isomeric dioxides were better separated than the corresponding unoxidized benzothiophenes. The influence of the substitution pattern on the retention indices is discussed.

Polycyclic aromatic sulfur heterocycles. II. Photochemical oxidation of benzo[b]thiophene in aqueous solution

Abstract Benzo[b]thiophene was irradiated in aqueous solution as a model compound for polycyclic aromatic sulfur heterocycles which are constituents of e.g. crude oils. The experiments were designed to simulate the photooxidation through sun-light in order to allow the identification of those products which can be expected from an oil-spill in the oceans. The primary photoproduct was benzo[b]thiophene-2,3-quinone which after hydrolysis, loss of carbon monoxide and oxidation of the sulfur atom ultimately was converted into 2-sulfobenzoic acid.

Photooxidation Products of Polycyclic Aromatic Compounds Containing Sulfur

Photooxidation of crude oil components is an important process that removes pollutants from the environment. Polycyclic aromatic compounds (PACs) are known to be toxic to many life forms, but little is known about their photooxidation products in the aqueous phase. We here identify a large number of photoproducts from 11 benzothiophenes, a polycyclic aromatic sulfur heterocycle that is a major representative of PACs in crude oil. The investigated compounds contain two to four methyl groups and an ethyl or an n-octyl group. In water, the products arise through oxidation of alkyl side chains to aldehydes and carboxylic acids or through an opening in one of the aromatic rings. The product analysis was performed using gas chromatography with mass spectrometric or atomic emission detection. The main product is always a sulfobenzoic acid, which strongly lowers the pH of the solution. With long alkyl substituents, surfactants are formed, which may possess solubilizing properties in water. The larger the number of alkyl groups, the faster is the photooxidation. Several of the identified acidic compounds were also found when whole crude oil was photooxidized, showing that simulation with individual compounds reflects the situation in whole crude.

Direct coupling of normal-phase high-performance liquid chromatography to atmospheric pressure laser ionization fourier transform ion cyclotron resonance mass spectrometry for the characterization of crude oil.

The high complexity of crude oil makes the use of chromatographic separation an important tool especially for sample simplification. The coupling of normal-phase high-performance liquid chromatography (HPLC) using a polar aminocyano column to a Fourier transform ion cyclotron resonance (FTICR) mass spectrometer offers the best attributes of good separation prior to ultrahigh resolution mass spectrometry (MS) detection. Atmospheric pressure laser ionization (APLI) was used as an ionization technique to analyze the nitrogen-containing aromatic compounds in a deasphalted crude oil due to its unique selectivity toward aromatic compounds and also due to its sensitivity. Two main chromatographic peaks were observed during this separation indicating a class-based separation. Mass spectra obtained from fractions were collected along the entire retention time and compared with each other to assign the unique constituents. By coupling the HPLC system directly to the FTICR mass spectrometer, comparable ion and UV chromatograms were obtained, reflecting the scan-to-scan sensitivity of the coupling system. The results show that it is possible to calculate reconstructed class chromatograms (RCC), allowing differences in class composition to be traced along the retention time. As an example, radical and protonated nitrogen species generated by APLI were detected along the retention time which enabled a differentiation between basic and nonbasic species in the same polar peak, thus overcoming the limitation of chromatographic resolution. This report represents the first online LC-FTICR MS coupling in the field of crude oil analysis.

Polycyclic Aromatic Sulfur Heterocycles in Desulfurized Diesel Fuels and Their Separation on a Novel Palladium(II)-Complex Stationary Phase

The lowering of the legal concentration of sulfur in fuels (in the European Union from 150 ppm at present to 50 ppm in 2004) not only affects the concentration but also the pattern of the polycyclic aromatic sulfur heterocycles (PASH) in the fuels. This pattern was studied for 12 diesel samples, most of which have been desulfurized. A separation of the PASHs and the polycyclic aromatic hydrocarbons becomes necessary at such sulfur levels. An efficient liquid chromatographic method for this is presented and involves a Pd(II)-containing complex based on 2-amino-1-cyclopentene-1-dithiocarboxylate covalently bonded to silica. The resultant PASH fraction can be analyzed by gas chromatography/flameionization detection.