Gasification of a South Australian low-rank coal with carbon dioxide and steam: kinetics and reactivity studies

Ye, D.P.; Agnew, John B.; Zhang, D.K.

doi:10.1016/s0016-2361(98)00014-3

Cited by 301 publications

(174 citation statements)

References 24 publications

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“…It is clear that the gasification rate increases with increased reaction temperature for both reactions and the optimum temperature is 900 °C over the ranges tested; physical operating constraints from the rig meant that it was not possible to operate above this temperature. These results agree with other studies where the temperature effect on different coal chars under CO 2 and H 2 O at atmospheric pressure was investigated and it was found that for the same reaction time (90 min at steady state) the carbon conversion increased with increasing temperature [12][13][14]. The maximum X a was at 0.13.…”

supporting

confidence: 90%

“…This rig consisted of a pressure vessel reactor (10), a carbolite furnace (9), a tar trap (12), a water cooled condenser (13), supplementary gas lines (1) and metering water pump (2). The pressure within the system was governed by a manually operated pressure regulator at the exit of the gas path (14), manually operated pressure regulators on the gas cylinders, a series of computer operated PID mass flow controllers (4), and safety pressure relief valves (7). Pressure levels within the system were monitored with pressure gauges (8), one before and one after the pressure vessel.…”

Section: Experimental Apparatusmentioning

confidence: 99%

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Experimental study on the impact of reactant gas pressure in the conversion of coal char to combustible gas products in the context of Underground Coal Gasification

Konstantinou

Marsh

2015

Fuel

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Underground Coal Gasification (UCG) is the process by which unmineable coal resources are converted in situ into a combustible gas. Pressurised oxidants such as steam and air or oxygen are injected into the coal seam in order to react with coal and form a product gas. The main gases produced are H 2 , CO, CH 4 and CO 2 , in proportions depending on temperature, pressure and the composition of the reactant gases injected [1][2][3]. Although it can be challenging to accurately measure or reproduce these conditions in a reliable fashion, it is generally believed that at high enough temperatures, free oxygen reacts completely with the solid carbon within a relatively short distance from the injection point. The heat evolved acts to pyrolyse the adjacent coal and the char formed then reacts with carbon dioxide, steam or other gases formed by combustion and pyrolysis [4][5][6]. The key substance, and hence driver of the net gasification process under these conditions is therefore CO 2 which is produced during the oxidation zone [5,7,8]. At the reduction zone CO 2 and steam, which is either introduced deliberately into the cavity or is flowing into the cavity from the oxidation of the surrounding strata, reacts with char and produces around 60% of the total gas product (by volume) during the UCG process. The remaining 40% is produced during the devolatilisation phase, although this is highly dependent on reactor condition, the type of coal and the gaseous reactants [4]. Fig. 1 illustrates the three reaction zones of a reacting channel during a UCG process, which are the oxidation, reduction and pyrolysis zones. During the oxidation zone, as the coal is consumed more coal falls into the growing void, which creates a high coal surface area available for reaction and permits contact between the hot gases and the coal [5,7]. This area is the final reduction zone which converts excess CO 2 to CO and is responsible for the uniform quality of the product gas. Measurement of the upstream gas composition in the oxidation zone has shown comparatively low heating values which demonstrate that the reactions in the oxidation zone do not have such a significant effect on the product gas composition [8,9]. Finally the pyrolysis zone is where the devolatilisation of the coal takes place, forming char that contains active sites for subsequent gas-solid reactions.Experimental study on the impact of reactant gas pressure in the conversion of coal char to combustible gas products in the context of Underground Coal Gasification AbstractThis paper describes an experimental investigation to determine the impact of pressurised reactor conditions within the reduction zone of a gasification process employing a semi-batch reactor with a bituminous coal. The conditions examined with this bespoke pressurised rig were designed to be representative of an Underground Coal Gasification (UCG) process, at pressures up to 3.0 MPa and temperatures up to 900 °C; coal samples were approximately 36 g per test. Current published literature suggests that one ...

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confidence: 90%

Section: Experimental Apparatusmentioning

confidence: 99%

Experimental study on the impact of reactant gas pressure in the conversion of coal char to combustible gas products in the context of Underground Coal Gasification

Konstantinou

Marsh

2015

Fuel

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“…Shufen and Ruizheng (1994), Ye et al (1998), Harris et al (2006) and Wu et al (2009) have investigated the effect of reaction time on carbon conversion during gasification. Ye et al (1998) investigated that fixed carbon conversion during CO 2 and H 2 O gasification is a function of reaction time and gasification temperature (Fig.…”

Section: Effect Of Reaction Time/residence Time On Coal Gasificationmentioning

confidence: 99%

Effect of operating parameters on coal gasification

Mishra

Gautam

Sharma

2018

Int J Coal Sci Technol

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Coal combustion and gasification are the processes to utilize coal for production of electricity and many other applications. Global energy demand is increasing day by day. Coal is an abundant source of energy but not a reliable source as it results into high CO 2 emissions. Energy industries are expected to decrease the CO 2 emission to prevent global warming. Coal gasification is a process that reduces the CO 2 emission and emerges as a clean coal technology. Coal gasification process is regulated by several operating parameters. A Number of investigations have been carried out in this direction. A critical review of the work done by several researchers in the field of coal gasification has been compiled in this paper. The effect of several operating parameters such as coal rank, temperature, pressure, porosity, reaction time and catalyst on gasification has been presented here.

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“…The carbon-sulfur complex is relatively stable, even at 950 C; thus, sulfur cannot be easily removed (Bandosz, 2006). The acidic demineralization of TC is known to reduce the content of activation catalyzers such as Ca and K. Ye et al (1998) showed that the carbon conversion rate is significantly lower when Ca þ K is reduced to <100 mg/kg. This agrees with that indicated by Wu et al (2003), who report that the time taken for coal to be 50% demineralized by HCl increases 2-4-fold when the original K content is <100 mg/kg.…”

Section: Characterization Of the Activated Carbonsmentioning

confidence: 99%

Preparation and characterization of activated carbon from the char produced in the thermolysis of granulated scrap tyres

López

Centeno

Rodríguez

et al. 2013

Journal of the Air & Waste Management Association

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The char produced in the thermolysis of granulated scrap tyres has few market outlets, reducing the economic viability of the thermolytic process. This paper reports the potential of this char as a low-cost precursor of porous carbons. The tyre-derived char was demineralized in either alkaline or acidic media to reduce its ash, zinc, sulfur, and silica contents. The lowest impurity content was achieved with an HNO 3 /H 2 O treatment. The resulting demineralized char was then subjected to activation by KOH or CO 2 . The Brunauer-Emmett-Teller (BET)-specific surface area of the activated carbon produced by the KOH treatment was 242 m 2 /g, whereas that of the CO 2 -activated carbon was 720 m 2 /g. The textural properties of the latter product were similar to those of some commercial activated carbons. The use of tyre-derived char as a precursor of porous carbons could render the thermolytic treatment of scrap tyres more economically attractive.Implications: Char produced in thermolysis of granulated scrap tyres has a few market outlets; in this paper an alternative for its use is presented. The char was converted into activated carbon with textural properties similar to those of some commercial activated carbons. This process could render the thermolytic treatment of scrap tyres more economically attractive.

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Gasification of a South Australian low-rank coal with carbon dioxide and steam: kinetics and reactivity studies

Cited by 301 publications

References 24 publications

Experimental study on the impact of reactant gas pressure in the conversion of coal char to combustible gas products in the context of Underground Coal Gasification

Experimental study on the impact of reactant gas pressure in the conversion of coal char to combustible gas products in the context of Underground Coal Gasification

Effect of operating parameters on coal gasification

Preparation and characterization of activated carbon from the char produced in the thermolysis of granulated scrap tyres

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