Differential Thermal Analysis of Inorganic Compounds

Gordon, Saul; Campbell, Clement

doi:10.1021/ac60103a018

Cited by 148 publications

(47 citation statements)

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“…At atmospheric pressure, CsNO3 has two stable phases (Gordon & Campbell, 1955;Plyuschev, Markina & Shklover, 1956;Cleaver, Rhodes & Ubbelohde, 1963;Kennedy, Taylor & Patterson, 1966); CsNO3(II)--,CsNO3(I) at 427 K. The room-temperature structure, CsNO3(II), has been determined previously by neutron (Lucas, 1983) and X-ray (Dean, Hambley & Snow, 1984) singlecrystal diffraction methods. The solution of this structure, however, was based on its isotypism to RbNO3(IV).…”

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confidence: 99%

Caesium nitrate (II) at 296 K

Pohl¹,

Gross

1993

Acta Crystallogr C

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Caesium nitrate (II) at 296 K

Pohl¹,

Gross

1993

Acta Crystallogr C

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“…The impregnated cell stacks were then heated to 700 °C for 1 h to decompose the Ba(NO 3 ) 2 into BaO. 700 °C was chosen to assure total decomposition, since a DTA experiments showed Ba(NO 3 ) 2 decomposed at 600-640 °C, even though the decomposition temperature reported by literature in general were lower, in the range 500-600 °C [21][22][23] . …”

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NOx conversion on LSM15-CGO10 cell stacks with BaO impregnation

Traulsen

Andersen

2012

J. Mater. Chem.

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The electrochemical conversion of NO x on non-impregnated and BaO-impregnated LSM15-CGO10 (La 0.85 Sr 0.15 MnO 3 -Ce 0.9 Gd 0.1 O 1.95 ) 5 porous cell stacks has been investigated, and extensive impedance analysis have been performed to identify the effect of the BaO on the electrode processes. The investigation was conducted in the temperature range 300-500 °C, a polarisation range from 3 V to 9 V and in atmospheres containing 1000 ppm NO, 1000 ppm NO + 10% O 2 and 10% O 2 . On the non-impregnated cell stacks no NO x conversion was observed at any of the investigated conditions. However, BaO impregnation greatly enhanced the NO x conversion and at 400 °C and 9 V polarisation a BaO-impregnated cell stack showed 60% NO x conversion into N 2 with 8% current efficiency in 1000 ppm NO + 10% 10 O 2 . This demonstrates high NO x conversion can be achieved on an entirely ceramic cell without expensive noble metals. Furthermore the NO x conversion and current efficiency was shown to be strongly dependent on temperature and polarisation. The impedance analysis revealed that the BaO-impregnation increased the overall activity of the cell stacks, but also changed the adsorption state of NO x on the electrodes; whether the increased activity or the changed adsorption state is mainly responsible for the improved NO x conversion remains unknown. IntroductionIn Europe the NO x -emission from the road transport has been significantly reduced during the last 10 years, mainly due to the introduction of the three-way-catalyst on gasoline vehicles 1 . Due to the negative impact of NO x -emissions on both human health and the environment 2 , a further reduction in the NO x emissions from the car fleet is desirable. However a major challenge in that connection is the increased number of diesel vehicles, as the conventional three-way-catalyst is incapable of removing NO x from diesel exhaust. For this reason much research is currently focused on NO x -removal technologies for diesel exhaust, the most heavily investigated technologies being selective catalytic reduction with ammonia (NH 3 -SCR), selective catalytic reduction with hydrocarbons (HC-SCR) and the NO x -storage and reduction (NSR) catalyst 3 . In all these three technologies there is the need for a reducing agent, either coming from operating the engine occasionally in an excess fuel to air-ratio (HC-SCR and NSR) or supplied by a separate system (NH 3 -SCR). A NO x removal technology without the need for the addition of a reducing agent would be simpler and therefore advantageous compared to the aforementioned technologies.A suggestion for such a technology is electrochemical NO x removal, where the NO x is reduced to N 2 and O 2 by electrons supplied to a polarised electrode 4 . The technology is inspired by the finding in 1975 by Pancharatnam et al. 5 that NO can be reduced to N 2 during polarisation of a zirconia based cell in the absence of oxygen, and later it was shown by Cicero et al. 6 and Hibino et al. 7 that NO x also could be electrochemically reduced in the...

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“…However, the concentration of particulate nitrates did not increase substantially. This is probably due to the fact that potassium nitrate and sodium nitrate decompose at 400 and 380 o C, respectively, which is well below the operating temperatures of the thermochemical conversion system [27].…”

Section: Characterization Of Integrated Samplesmentioning

confidence: 99%

The effect of oxygen on formation of syngas contaminants during the thermochemical conversion of biomass

Schuetzle¹,

Schuetzle²,

Hoekman

et al. 2015

Int J Energy Environ Eng

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The effect of oxygen on the formation of syngas contaminants during the thermochemical conversion of carbonaceous feedstocks has been quantified using an integrated biorefinery plant operated at a biomass input of about 4.5 metric tons/day. This plant combines solids steam reforming and gases steam reforming processes for the conversion of biomass to syngas. It was found that the presence of low concentrations of oxygen (in air) during the thermochemical conversion process had a significant effect on the formation of contaminants in the syngas. For example, particulate organic carbon compounds (organic particulate contaminants) increased from 3.3 to 122 mg/m 3 when the oxygen input was increased from 225 ppm to 4.1 vol.% during the thermochemical conversion of wood to syngas. It is proposed that the primary free radical ( Ã ) species H Ã , OH Ã , O Ã , CH 3 Ã and OOH Ã , formed from the presence of O 2 in this high-temperature process, react with the myriad of organic compounds in the syngas at varying rates, depending upon their structure and reactivity. These processes represent the primary chemical mechanisms for the formation of high molecular weight hydrocarbons, polynuclear aromatic hydrocarbons, oxygenated hydrocarbons and polymeric materials, commonly referred to as organic particulate contaminants. The potential importance of these free-radical oxidation processes was supported by measuring the concentrations of selected oxygenated hydrocarbons in the syngas over a range of 225 ppm to 4.1 vol.% of O 2 in the thermochemical process. The concentrations of oxygenated polycyclic aromatic hydrocarbons (hydroxy-naphthalene, dihydroxy-naphthalene, dihydro-indene-2-one, and benzopyranone) increased by 732, 244, 83 and 195 times, respectively, when the oxygen concentration was increased from 225 ppm to 2.5 vol.%. These increases were due to the free-radical oxidation of the highly reactive PAHs during the thermochemical processes. The importance of these oxidation processes was further confirmed by studying the decrease of easily oxidized olefins. For example, the concentrations of 1,3-butadiene, acetylene, propene and ethene decreased by 9.3, 5.2, 4.5 and 3.4 times, respectively, when oxygen in the plant was increased from 1.6 to 2.5 vol.%. It is concluded that the formation of organic particulate contaminants during the thermochemical conversion of carbonaceous feedstocks can be minimized by maintaining the concentration of oxygen below 500 ppm.

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Differential Thermal Analysis of Inorganic Compounds

Cited by 148 publications

References 7 publications

Caesium nitrate (II) at 296 K

Caesium nitrate (II) at 296 K

NOx conversion on LSM15-CGO10 cell stacks with BaO impregnation

The effect of oxygen on formation of syngas contaminants during the thermochemical conversion of biomass

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