Showing papers in "Fuel in 1994"

TL;DR: In this paper, a colony-forming microalga with high moisture content was performed with or without sodium carbonate as a catalyst for conversion into liquid fuel and recovery of hydrocarbons.

TL;DR: In this article, the following topics are covered: devolatilization of nitrogen compounds from solid fuel; homogeneous gas phase reactions; oxidation of char-nitrogen; gas-solid reactions; heterogeneous catalytic reactions; and ways in which knowledge of the chemistry and kinetics can be applied to combustor modelling and operation.

TL;DR: A number of analytical methods have been developed for approximating the sulfur functional group compositions of coals as discussed by the authors, and some of these are destructive tests depending on pyrolysis or catalytic reduction to H 2 S or oxidation to SO 2.

TL;DR: In this paper, the transformation of coal into char during low-temperature pyrolysis was studied by Fourier transform infrared (FT-i.r.) spectroscopy and solvent swelling measurements.

TL;DR: In this paper, the possibilities and limitations of experimental and theoretical methods of non-isothermal reaction kinetics applied to the investigation of the interaction of coal structure and pyrolysis behavior, including the interpretation and application of results on relevant organic substances of well-defined structure.

TL;DR: In this paper, three major sintering mechanisms are identified and considered to be important in CFB combustion: partial melting, viscous flow and gas-solid chemical reactions, and they are compared with the results obtained with a test on cylindrical coal ashes.

TL;DR: In this article, the free-radical mechanism of oxidation and deposit formation was investigated and the results were shown to be incompatible with previous mechanisms concerning the source of deposit precursors, and it was proposed that the presence of naturally occurring antioxidant molecules plays an important role in both inhibiting the oxidation of the fuel and forming deposits.

TL;DR: In this article, a review of the relationship between maceral types and reactivity is presented, and the main conclusion from this review is that any predictive system needs to take all these factors into account, especially reflectance.

TL;DR: In this paper, the results obtained in the characterization of different pyrolysis oils, five oils produced by carbonization and one by flash combustion, were first determined, then an in-depth chemical characterization was carried out by liquid-liquid fractionation.

TL;DR: In this paper, the authors provide an account and an evaluative assessment of technological advances in the manufacture of liquid fuels from synthesis gas (hydrogen and carbon oxides), and suggest opportunities for future research deemed promising for the installation of practical processes.

TL;DR: In this article, activated carbon was oxidized using H2O2 aqueous solutions and the surface oxygen groups were identified by FT-i.r. spectroscopy, the influence of solution concentration and pH, outgassing and oxidation conditions of the carbon, and the addition of catalytic or stabilizer agents to the oxidizing solution was investigated.

TL;DR: In this paper, the partial precipitation of asphaltene in a fixed amount of aromatic hydrocarbon system, with gradual additions of paraffinic hydrocarbon (such as pentane), in the presence of various surfactants has been studied.

TL;DR: In this article, a mathematical model for spontaneous combustion of coal has been developed that takes into consideration the moisture content of coal, and a first-order Arrhenius reaction rate for oxidation under pore diffusion and chemically controlled reaction regimes is considered.

TL;DR: In this article, the same fuel samples were performed using five different experimental techniques and the system variables examined were the sample mass, the particle heating rate, the way in which the particles are heated, the surrounding gas conditions, and the definition of particle ignition.

TL;DR: In this article, a 0.5 MW test combustor burning pulverized coal, with burner or in-furnace air-staging, was investigated with an unburnt carbon content of ~10 wt%, acceptable for small test facilities.

TL;DR: In this paper, the conversion of fuel-nitrogen to HCN and NH3 and to nitrogen oxides was studied with nitrogen-containing model compounds, chosen to represent the main nitrogen and oxygen functionalities in fossil fuels.

TL;DR: The role of inorganic matter in causing agglomeration and defluidization during the circulating fluidized-bed combustion of high-sodium, high sulfur low-rank coals was reported in a previous paper as mentioned in this paper.

TL;DR: In this article, a wide range of chars prepared in an entrained-flow reactor from coals and vitrinite concentrates of different rank and geographic origin were studied, and it was shown that the fractional conversion of char-N to NO increased with increasing rank of the original coal at first and then reached a plateau above a vitriner reflectance of ~ 1.5%.

TL;DR: In this paper, the effects of wood species and carbonization conditions, such as temperature, heating rate and soaking time, were determined, and both reactivity and activation energy for the gasification of wood chars were found to be strongly influenced by the carbonisation conditions employed during their preparation and wood type.

TL;DR: In this paper, the courses of the thermal breakdown reactions in coal pyrolysis and liquefaction were compared using similar coal and maceral concentrate samples in parallel experiments, and the results suggest that the sensitivity of pyrolysis yields to changes in heating rate is related to competing rates of volatile release and resolidification within the pyrolynsing mass: the presence of locally available hydrogen (e.g. from hydrogen donor species) appears to shift this competition in favour of greater product release and slower resolidization.

TL;DR: In this article, a mathematical model was developed to predict tar and extractables yields from rapid pyrolysis of softening coals, and the model accounts for intraparticle transport and secondary reactions of liquids generated by coal pyrotelysis, and satisfyingly captures important features of the current experimental data.

TL;DR: In this paper, a three-dimensional computer simulation developed to predict the behavior of industrial pulverized coal furnaces is presented, where the main characteristics of the current model are the use of the Lagrangian framework to describe the particulate phase, the discrete transfer model to handle the radiation transmission and the standard k−e model for turbulence treatment.

TL;DR: The surface tension of bitumen recovered from Whiterocks tar sand was determined to be 23.6m Nm−1 at 20 °C and 20.5 m Nm −1 at 60 °C using the Wilhelmy plate technique as mentioned in this paper.

TL;DR: In this article, the authors investigated the NOx-reduction efficiency of different reburning fuels by combustion tests on a 0.5 MW(th) pulverized fuel rig.

TL;DR: In this paper, a kinetic study of the pressurized gasification of a lignite char with CO 2, H 2 and steam using a packed bed balance reactor (PBBR) system is presented.

TL;DR: In this paper, Toluene-extracted lipids from a dried raw Atlanta sewage sludge were pyrolysed over activated alumina at 450 °C and atmospheric pressure, showing that even carboxylic acids, the major component of the separated lipid fraction, did not survive the pyrolysis reaction.

TL;DR: In this paper, the current state-of-the-science in coal characterization, combustion and liquefaction is discussed, along with suggested research opportunities in each area, coupled with an assessment of the impact such research programmes could have if successful.

TL;DR: In this paper, the formation and destruction of nitrogenous species in fuel-rich zones caused by air staging and reburning were explored in a laboratory coal combustor, and the same simplified, but fundamentally based, gas phase mechanism would predict time resolved profiles of all NOous species, for both NO x abatement procedures.

TL;DR: In this article, the chemistry of fuel-bound nitrogen in pulverized coal flames has been extensively studied in both small-scale turbulent coal flames and large-scale laboratory flames.

TL;DR: In this paper, two artificial coalification series were obtained by pyrolysing an immature coal in hydrous and confined systems, and the solid residues as well as extractable liquid hydrocarbons were analysed.