Search results for "absorptio"
showing 10 items of 2815 documents
Landfill gas upgrading with pilot-scale water scrubber: Performance assessment with absorption water recycling
2012
Abstract A pilot-scale counter current absorption process for upgrading municipal solid waste (MSW) landfill gas to produce vehicle fuel was studied using absorption, desorption and drying units and water as an absorbent. Continuous water recycling was used without adding new water to the system. The process parameters were defined by a previous study made with this pilot system. The effect of pressure (20–25 bar), temperature (10–25 °C) and water flow speed (5.5–11 l/min) on the upgrading performance, trace compounds (siloxanes, halogenated compounds) and water quality were investigated. Raw landfill gas flow was kept constant at 7.41 Nm3/h. Methane (CH4) and carbon dioxide (CO2) contents …
Upgrading landfill gas using a high pressure water absorption process
2014
Abstract The upgrading of landfill gas (methane 54.2 ± 2.0%, carbon dioxide 42.1 ± 2.4% and nitrogen 3.7 ± 1.2%) was studied with a pilot-scale high pressure water absorption system consisting of absorption, desorption and gas drying units. The gas was upgraded in two phases and with two absorption columns operating in sequence in pressures up to 180 bar, and with initial pressures of 8 and 10 bar. This type of high pressure process, where water is used for increasing the gas pressure, does not need a separate compression unit to produce the gas pressure required by gas vehicles. Product gas with a methane contents ranging from 83.0% to 92.1% was achieved with differing process parameters, …
The vibrational levels of methane obtained from analyses of high-resolution spectra
2006
International audience; Methane and its tetrahedral isotopologues are spherical-top molecules whose high-resolution rovibrational spectra can only be analyzed in detail, thanks to sophisticated symmetry-adapted tensorial models. However, the effective Hamiltonian parameters of such models do not give direct access to the positions of the vibrational sublevels. In this paper, we present a calculation of the vibrational level positions for 12CH4, 13CH4, 12CD4 and 13CD4 performed using the effective Hamiltonian parameters obtained through recent analyses. We also include the results of a re-analysis of the octad system of 12CH4 performed with a higher order of the development which slightly im…
A five-coordinate manganese(iii) complex of a salen type ligand with a positive axial anisotropy parameter D.
2017
A new high-spin d4 roughly trigonal–bipyramidal (TBP) manganese(III) complex with a salen type ligand (H2L), namely MnL(NCS)·0.4H2O, has been synthesised and characterised by elemental analysis, ESI mass spectrometry, IR and UV-vis spectroscopy, and spectroelectrochemistry. X-ray diffraction analysis revealed an axial compression of the approximate TBP. Temperature dependent magnetic susceptibility and variable-temperature variable-field (VTVH) magnetisation measurements, as well as high-frequency and -field EPR (HFEPR) spectroscopy, were used to accurately describe the magnetic properties of this complex and, in particular, determine the spin Hamiltonian parameters: g-values and the zero-f…
Mechanochemical Synthesis, Photophysical Properties, and X-ray Structures of N-Heteroacenes
2016
The described mechanochemical methodology is an example of a proof-of-concept in which solution-based tedious, poor yielding, and difficult syntheses of pyrazaacenes are achieved under solvent-free ball-milling conditions; the method is easy, high yielding, time-efficient, and environmentally benign. The synthesized compounds also include pyrazaacenes (N-heteroacenes) that are octacene analogues containing pyrene building blocks. The compounds were sparingly soluble in common solvents, and column chromatographic purifications could be avoided after the solvent-free syntheses. The UV/Vis absorption spectra of the pyrazaacenes show intense absorption bands in the near-IR region. The single-cr…
Molecular balance forms of indium phthalocyanines in benzene and pyridine solution
2019
Abstract The electronic absorption spectra of In2Pc3, InPc2 and InPcI solid compounds after dissolvation in one of the most commonly used solvents, i.e.: benzene and pyridine have been measured. In benzene, the molecules of the diindium tripledecker phthalocyanine, In2Pc3, undergoes transformation to ionic couples [InPc]+[InPc2]-, whereas when the InPc2 compound is dissolvated, the molecules of the indium sandwiches, InPc2, remain relatively stable in the solvent. When the In2Pc3 compound is dissolvated in py, the inner Pc(2-) ring of diindium tripledecker phthalocyanine molecule undergoes disjunction and rejection. In the results of it in the solution the couple of chromophores, being in t…
[Pt2Cu34(PET)22Cl4]2–: An Atomically Precise, 10-Electron PtCu Bimetal Nanocluster with a Direct Pt–Pt Bond
2021
Heteroatom-doped metal nanoclusters (NCs) are highly desirable to gain fundamental insights into the effect of doping on the electronic structure and catalytic properties. Unfortunately, their controlled synthesis is highly challenging when the metal atomic sizes are largely different (e.g., Cu and Pt). Here, we design a metal-exchange strategy that enables simultaneous doping and resizing of NCs. Specifically, [Pt2Cu34(PET)22Cl4]2- NC, the first example of a Pt-doped Cu NC, is synthesized by utilizing the unique reactivity of [Cu32(PET)24Cl2H8]2- NC with Pt4+ ions. The single-crystal X-ray structure reveals that two directly bonded Pt atoms occupy the two centers of an unusually interpenet…
Electronic Absorption Spectra of HXeCl, HXeBr, HXeI, and HXeCN in Xe Matrix
2000
The electronic UV absorption spectra of thermal reaction products H−Xe−Y (Y= Cl, Br, I, or CN) have been measured in solid Xe at 12 K. The spectra are obtained after the annealing of an extensively...
Characterization of triphenylamino-based polymethine dyes
2013
In this high-technology application, age functional dyes especially polymethine dyes have captured much attention of the researchers due to their immense potential for high-tech uses. Polymethine dyes show promising absorption spectra in the visible range, which can be easily exploited for the use of written text copying, photographic imaging, or photothermographic recording materials. Keeping this in mind, our research is composed of an investigation of two triphenylamino-based polymethine dyes, a known polymethine dye 3 and a new one polymethine dye 5, which have been synthesized by the reaction of 4-(diphenylamino) benzaldehyde 2 and 4,4′-(phenylazanediyl) dibenzaldehyde 4 with 4,4′-viny…
Carbon-13 chemical shifts of bicyclic compounds
1970
13C NMR absorption spectra of 50 bicyclic hydrocarbons, alcohols and ketones have been measured, in addition to some terpenes. The 13C chemical shifts are approximately additive for similar compounds and can be used for the determination of molecular structure; they differ for endo- and exo-isomers, just as in proton spectra. These quite regular and predictable 13C shift differences are much larger and are caused by the 1,4-nonbonded interaction between atoms heavier than hydrogen, not by magnetic anisotropy effects.