Topic
Carbochemistry
About: Carbochemistry is a research topic. Over the lifetime, 1010 publications have been published within this topic receiving 16626 citations.
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TL;DR: In this article, a detailed phenomenological study of the gasification behavior of a North Dakota lignite was undertaken and the fundamental parameters that determine char reactivity were investigated by varying the conditions of coal pretreatment and pyrolysis, and the observed reactivity differences were rationalized in terms of variations in the concentration of carbon and catalyst active sites.
83 citations
TL;DR: In this paper, coal particles with diameters of 3-11 mm were injected into a small, hot bed of sand fluidized by nitrogen and their evolution was followed by sampling the exit gas stream and subsequent analysis by gas chromatography, concluding that heat transfer is the main process controlling the volatilization time in fluidized bed combustors.
82 citations
TL;DR: In this paper, the pyrolysis of brown coal samples and bituminous coal maceral concentrates was investigated by non-isothermal thermogravimetry, and the TG data for these coals reveal a two-stage pyroolysis process.
Abstract: The pyrolysis of a suite of brown coal samples and bituminous coal maceral concentrates is investigated by non-isothermal thermogravimetry. The TG data for these coals reveal a two-stage pyrolysis process. The activation energy for the primary pyrolysis stage is considerably higher than that for the secondary pyrolysis stage. It is evident that a particular coal may be characterised by the weighted mean apparent pyrolysis activation energy which correlates with the corresponding specific energy of the coal.
81 citations
TL;DR: In this article, the effect of ion-exchanged metals on the yield and composition of coal tar was investigated in a fluidized bed reactor at temperatures of 600 to 1000°C by Fourier transform infrared (FTIR) spectroscopy.
Abstract: In order to investigate the effect of ion-exchanged metals on the yield and composition of coal tar, we have pyrolyzed raw and calcium-exchanged Yallourn brown coal in a fluidized bed reactor at temperatures of 600 to 1000°C and have analyzed the product tars by Fourier transform infrared (FTIR) spectroscopy. At the lower temperatures (600-800°C), tar yields are lower for the calcium form coal than for the raw coal, indicating that the calcium either promotes tar conversion to char or tightens the coal structure and makes it difficult for larger tar molecules to escape
79 citations
TL;DR: In this article, a model for the rapid devolatilization of individual coal particles is developed by analogy with a single-stage equilibrium flash distillation, and the model accurately correlates the yields of noncondensible gas and tar from bituminous coals over wide ranges of temperature and pressure.
Abstract: A model for the rapid devolatilization of individual coal particles is developed by analogy with a single-stage equilibrium flash distillation. In the theory, thermal depolymerization of the coal generates aromatic fragments that are widely distributed in size. Conditions for phase equilibrium determine the partitioning of these fragments into intermediates in the condensed phase, which ultimately form char and light gas, and into tar vapor, which escapes in a stream of light gases. Comparison with data shows that the model accurately correlates the yields of noncondensible gas and tar from bituminous coals over wide ranges of temperature and pressure. The predicted molecular weight distributions of tar are also in agreement with measured distributions, and the model yields a mechanistic basis for their observed insensitivity to temperature. The tendency to form lighter tar at higher pressures is also explained.
79 citations