Volatilisation and catalytic effects of alkali and alkaline earth metallic species during the pyrolysis and gasification of Victorian brown coal. Part VI. Further investigation into the effects of volatile-char interactions

The purpose of this study is to further investigate the effects of volatile-char interactions on the volatilisation and dispersion of alkali and alkaline metallic species and changes in char structure during pyrolysis. Ion-exchanged (H-form, Na-form and Ca-form) Loy Yang brown coal samples were pyrolysed in a novel two-stage fluidised-bed/fixed-bed reactor over a wide temperature range of 500-930 °C. Our results indicate that soot formation and destruction on char (pore) surface during volatile-char interactions could be catalysed by Na and, to a lesser extent, Ca on char. Volatile-char interactions caused additional volatilisation of Na at temperatures higher than 700 °C although there are no effects on the volatilisation of Ca. The formation and simultaneous (catalytic) destruction of soot on char surface are closely linked to the volatilisation of Na from the char. Volatile-char interactions have also caused changes in char structure and/or changes in Na/Ca dispersion, as is reflected by the reduction in char reactivity. These results indicate that the volatile-char interactions are not limited on the char surface. It appears that H radicals must have penetrated into the char structure during volatile-char interactions.     

E.p.r. study of paramagnetic metal ions in Victorian brown coal

Electron paramagnetic resonance (e.p.r.) spectra of some Victorian brown coals in the raw state possess absorbances attributable to metal ion radicals. E.p.r. signals at g≈4.3 and g≈2 (multiplet) have been assigned to iron(III) and manganese(II), respectively. The g≈4.3 signal intensity does not appear to vary directly with the total iron content of the raw coal. The amplitudes of the metal ion signals were found to change with drying of the coal, and were reduced to zero on removal of the metal ions by acid washing. Ion exchange of the sodium form of brown coal with iron(III) reintroduced the g≈4.3 signal and produced an additional broad signal centred at g≈2. The intensity of the latter signal was related to the total iron content of the iron(III)-exchanged coal. The extent of iron(III) exchange was shown to be pH dependent. Other paramagnetic ions, such as oxovanadium(IV), manganese(II) and copper(II) when exchanged onto brown coal produced their characteristic metal ion spectra.     

科学传播：我们迷失了什么

随着科学传播理论研究的不断深入,对科学传播的目的性和必要性已逐渐形成共识,而如何进行更有效的科学传播,即科学传播中的策略问题,越来越成为科学传播领域急需解决的重要问题。本文主要基于对Christopher Hamlin教授观点的分析得出科学传播多方互动的网络模式。     

A response to Roger Taylor

Abstract

Roger Taylor, in his response to my paper, may unwittingly have provided us with the answer to why Antoine Claudet distanced himself so firmly from the drawn out machinations and negotiations that led in January 1853 to the formation of what is now the Royal Photographic Society. It was snobbery. Taylor highlights the social chasm that existed between those in trade and those in polite society in the middle of the nineteenth century. ‘It is difficult to appreciate’, he reminds us, ‘just how conspicuously separate the two photographic communities (daguerreotype and calotype) were in the 1850s’.     

Understanding the significance of in situ coal properties for CO2 sequestration: An experimental and numerical study

Over the years, there has been a rapid increase in atmospheric CO₂ concentrations, from 280 ppm in 1850 to 360 ppm in 1998. Therefore, mitigation methods such as carbon sequestration in subsurface reservoirs have been suggested. CO₂ sequestration is attractive, especially in relation to coal, with the additional potential benefit of CH₄ recovery. However, the potential of CO₂ sequestration is not well understood for various types of coals due to important in situ properties of coal. In this study, data from previous studies for coal permeability, density, moisture content, mineral content, vitrinite reflectance, compressive strength and temperature are compared with the CO₂ adsorption results to understand the significance of these in situ coal properties on CO₂ sequestration. To verify the findings, a custom‐designed advanced core flooding apparatus is used to simulate the effects of various in situ properties on CO₂ sequestration. This apparatus can test samples of 203 mm in diameter and up to 1000 mm in length. Hence, heterogeneity effects can be understood, as previous CO₂ sequestration‐related formulae have been based on coal samples of sizes ranging up to only about 100 mm. However, initially, a reconstituted coal core sample has been used to simplify the heterogeneity effects. Flow rates are estimated by analysing the lag of downstream pressures over time. With the use of a 203‐mm‐diameter and 816‐mm‐long reconstituted Victorian brown coal sample, flow rate reductions of 70% and 98% are observed for injection pressures of 2 and 4 MPa, respectively, due to CO₂ injection. This study highlights the appropriateness of a candidate coal reservoir for CO₂ storage in terms of in situ properties. Copyright © 2013 John Wiley & Sons, Ltd.     

The rise and fall of cast iron in Victorian structures – A case study review

The Victorian era in English history is often referred to as a ‘golden age’, marked by unique and historic achievements in the field of engineering and technology. It was in Victorian Britain that new production methods first allowed cast iron to be produced in large enough quantities to be used in substantial building projects. However, a series of high profile structural failures sent shock waves through the engineering profession and general public, prompting one of the first ever systematic investigations into the failure of structures. To track these developments, this paper takes a retrospective view of a number of major cast iron structural disasters that occurred during this period of history. Reassessment of historic incidents will allow use of modern analytical techniques not available at the time of initial investigation. A specific case study analysis into the demise of the Tay Bridge is used to demonstrate the value of engineering lessons to be learnt from taking a retrospective view. Reconsideration of historic failure is shown to demonstrate incremental advances made in the understanding of the limits of materials available at that time.     

Psychopharmacology and the mystery of The Moonstone..

Contends that W. Collins's (1871 [1966]) detective novel, The Moonstone, is remarkable not only for the exploitation of psychological principles but also the recognition of these principles before their discovery by psychologists. Drug dissociation (reported by psychologists in the 1930's) is central to the novel. It is suggested that Collins was a reader of Victorian physiological and phrenological literature, a laudanum addict, and given to introspective analyses of his experiences with opium. (12 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Evidence of poly-condensed aromatic rings in a Victorian brown coal

An attempt was made for obtaining UV/VIS absorption and fluorescence spectra of a whole Victorian brown coal and then examining the presence of aromatic ring systems (ARSs) with poly-condensed rings in the coal. Loy Yang brown coal was subjected to an alkali-promoted depolymerization in an aqueous solution of sodium hydroxide at 473 K and then dissolved nearly completely into the solution. The solution of the solubilized coal was analyzed by UV/VIS absorption and fluorescence spectroscopies. The spectra of the solubilized coal were compared with those of a tar that was produced from the rapid pyrolysis of the coal in a wire-mesh reactor. Absorbance of the solubilized coal per unit molar concentration of aromatic carbon and unit light path length was averaged over 50 nm wavelength intervals in a range from 250 to 600 nm. The averaged absorbance of the solubilized coal was much greater than those of mono-aromatic compounds and lignin at intervals from 400 to 600 nm while comparable to those of tetra- to hexa-aromatic compounds, suggesting that the coal is abundant of ARSs with poly-condensed rings. The fluorescence spectra of the solubilized coal also give indication of the presence of ARSs with three to six condensed rings. Furthermore, the presence of even larger ARSs is evidenced from appreciable difference in apparent quantum yield of the solubilized coal and that of the tar. By comparing the absorption and fluorescence spectra of the solubilized coal with those of the tar, it was revealed that the tar is richer in relatively small poly-ARSs than the solubilized coal while the larger poly-ARSs are abundant in the solubilized coal. Smaller poly-ARSs were thus released from the coal preferentially to larger poly-ARSs during the pyrolysis.     

Outward Views: Rights and Utility in Victorian State Planning

A long-standing urban planning maxim has been that there is no right to a view. However, the Victorian planning apparatus is increasingly admitting shared rights to outward views. This article explores this movement towards a procedural logic based upon inter-subjective and place-based understandings of rights and utility.     

Generation of ultra-clean coal from Victorian brown coal — Sequential and single leaching at room temperature to elucidate the elution of individual inorganic elements

This paper addressed the probability of the generation of ultra-clean coal from chemical leaching of low-rank Victorian brown coal. Sequential leaching was employed to determine the modes of occurrence of the major elements in the two coals studied, including Na, K, Mg, Ca, Fe, Al, Ti, and Si. The results indicate that, the modes of occurrence of individual metals vary greatly with brown coal sample and elemental type. For one brown coal tested, it is dominated by water-soluble and ammonium acetate-soluble ion-exchangeable cations. Therefore, a single washing through the use of woody biomass-derived pyroligneous acid or citric acid easily reduced the concentrations of its overall ash and even sulphur and chlorine to meet the requirements for gas turbine fuel. The leaching of the organically bound cations in this coal was also very rapid and completed in 5 min. In contrast, another brown coal tested is mainly composed of quartz and/or clay compounds which remained intact even after being leached with 5 M nitric acid. These mineral grains possess two peak size ranges in the coal, 1.0-2.2 μm and 4.6-10 μm. The former size bin was embedded deeply in coal matrix, and hence, its leaching upon acids was very slow when compared with coarse particles which are mostly discrete grains residing separately from coal matrix. The Na-EDTA was found to be able to mobilise the small grains substantially through its Na ion to penetrate coal matrix to react with Al, forming acid-soluble Na aluminates. The ammonium acetate-insoluble Ti and Fe polyhedra were also mobilised by the EDTA. Accordingly, the overall ash content in coal residue accounts for ~ 1.5 wt.%, relative to 2.6 wt.% in the corresponding raw coal and 2.0 wt.% in the ammonium acetate-insoluble residue.