Experimental analysis of the combustion characteristics of Estonian oil shale in air and oxy-fuel atmospheres

Loo, L; Maaten, Birgit; Siirde, Andres; Pihu, T.; Konist, Alar

doi:10.1016/j.fuproc.2014.12.051

Cited by 37 publications

(28 citation statements)

References 28 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In general, mineral matter of oil shale can be divided into two separate parts, carbonate and sandy‐clay matter. The carbonate contents of oil shales from Estonia and Jordan account for approximately 0.6–0.8 g/g (60–80 mass%) on a dry ash mass basis, consisting mainly of calcite and dolomite greater than 0.95 g/g (95 mass%) of their contents . The global activation energies of oil shale pyrolysis processes determined in this study are in close agreement with the values for each stage reported as 132–200 kJ/mol and 273 kJ/mol for Estonian oil shales, and 65–75 kJ/mol and 171 kJ/mol for Jordanian oil shales, respectively .…”

Section: Resultssupporting

confidence: 85%

“…The carbonate contents of oil shales from Estonia and Jordan account for approximately 0.6-0.8 g/g (60-80 mass%) on a dry ash mass basis, consisting mainly of calcite and dolomite greater than 0.95 g/g (95 mass%) of their contents. [7,22,30,31] The global activation energies of oil shale pyrolysis processes determined in this study are in close agreement with the values for each stage reported as 132-200 kJ/mol and 273 kJ/mol for Estonian oil shales, and 65-75 kJ/mol and 171 kJ/mol for Jordanian oil shales, respectively. [22,25,32,33] In addition, comparison of literature data shows that the kinetic parameters are unique to each individual case of oil shale, as the values for Turkish, Moroccan, and Chinese oil shales are reported within the ranges of 13-70 kJ/mol, 70-110 kJ/mol, and 240-270 kJ/mol, respectively.…”

Section: Kinetic Analysissupporting

confidence: 84%

See 1 more Smart Citation

Pyrolysis and char oxidation characteristics of oil shales and coal in a thermogravimetric analyzer

Park

Song

2017

Can J Chem Eng

View full text Add to dashboard Cite

Non‐isothermal thermogravimetric analysis was carried out on two different oil shales and sub‐bituminous coal in order to evaluate effects of the fuel properties and compare the reaction characteristics. The samples and their chars after the devolatilization were heated up to 900 °C at a constant heating rate of 10 K/min under inert and oxidizing atmospheres, respectively. Experimental results exhibit distinct behaviour between the samples for both pyrolysis and char oxidation processes. Pyrolysis of oil shale occurs in two temperature regimes corresponding to its organic and mineral degradation, and mineral matter plays important roles in production of the residual char at the second pyrolysis stage and its reactivity to the subsequent char oxidation. Kinetic analysis was performed using the global one‐ and multi‐step models with nth order reaction mechanism. Organic devolatilization processes of coal and oil shale are analyzed by three‐ and two‐step models, respectively, however mineral degradation of oil shale and char oxidation are analyzed by a one‐step model. Finally, a reasonable fit to the experimental data can be achieved for all the samples and their chars at different atmospheres.

show abstract

Section: Resultssupporting

confidence: 85%

Section: Kinetic Analysissupporting

confidence: 84%

Pyrolysis and char oxidation characteristics of oil shales and coal in a thermogravimetric analyzer

Park

Song

2017

Can J Chem Eng

View full text Add to dashboard Cite

show abstract

“…Slight drop of primary air temperature from 284 to 250 • C was noticed. This might be the reason for decreased temperatures in the riser, together with decreased fuel reactivity and increased heat capacity of the CO 2 atmosphere [15]. During the experiment with an increased O 2 concentration (OXY30), the temperature distribution was similar to air mode.…”

Section: Description Of the Experimentsmentioning

confidence: 98%

“…Substituting N 2 with CO 2 has an influence on combustion, pollutant formation, mineral matter behavior and temperature in the combustor. Previous research has shown that, when the oxidizer contains a similar amount of O 2 , then, in CO 2 , the combustion is delayed [15][16][17]. Delayed combustion and increased specific heat of the gas mix leads to up to a 100 • C temperature decrease in the furnace [3,18].…”

Section: Introductionmentioning

confidence: 99%

Ash and Flue Gas from Oil Shale Oxy-Fuel Circulating Fluidized Bed Combustion

et al. 2018

Self Cite

View full text Add to dashboard Cite

Carbon dioxide emissions are considered a major environmental threat. To enable power production from carbon-containing fuels, carbon capture is required. Oxy-fuel combustion technology facilitates carbon capture by increasing the carbon dioxide concentration in flue gas. This study reports the results of calcium rich oil shale combustion in a 60 kW th circulating fluidized bed (CFB) combustor. The focus was on the composition of the formed flue gas and ash during air and oxy-fuel combustion. The fuel was typical Estonian oil shale characterized by high volatile and ash contents. No additional bed material was used in the CFB; the formed ash was enough for the purpose. Two modes of oxy-fuel combustion were investigated and compared with combustion in air. When N 2 in the oxidizer was replaced with CO 2 , the CFB temperatures decreased by up to 100 • C. When oil shale was fired in the CFB with increased O 2 content in CO 2 , the temperatures in the furnace were similar to combustion in air. In air mode, the emissions of SO 2 and NO x were low (<14 and 141 mg/Nm 3 @ 6% O 2 , respectively). Pollutant concentrations in the flue gas during oxy-fuel operations remained low (for OXY30 SO 2 < 14 and NO x 130 mg/Nm 3 @ 6% O 2 and for OXY21 SO 2 23 and NO x 156 mg/Nm 3 @ 6% O 2 ). Analyses of the collected ash samples showed a decreased extent of carbonate minerals decomposition during both oxy-fuel experiments. This results in decreased carbon dioxide emissions. The outcomes show that oxy-fuel CFB combustion of the oil shale ensures sulfur binding and decreases CO 2 production.

show abstract

“…Researchers have in-depth studied the characteristics of temperature rise and gas production of oil shale based on the pyrolysis temperature, temperature increase rate, retention period, pyrolysis atmosphere, operating pressure, particle size and density, as well as inorganic content [8][9][10][11][12]. Ots analyzed the formation of nitrogen oxides, sulfur oxides, polycyclic aromatic hydrocarbons and ash in oil shale direct-combustion process [13].…”

Section: Of 12mentioning

confidence: 99%

Study on Low Temperature Oxidation Characteristics of Oil Shale Based on Temperature Programmed System

Wang

Liu

et al. 2018

Energies

View full text Add to dashboard Cite

Oil shale is a kind of high-combustion heat mineral, and its oxidation in mining and storage are worth studying. To investigate the low-temperature oxidation characteristics of oil shale, the temperature, CO, alkane and alkene gases were analyzed using a temperature-programmed device. The results showed that the temperature of oil shale underwent three oxidation stages, namely a slow low-temperature oxidation stage, a rapid temperature-increasing oxidation stage, and a steady temperature-increasing stage. The higher the air supply rate is, the higher the crossing point temperature is. Similar to coal, CO also underwent three stages, namely a slow low-temperature oxidation stage, a rapid oxidation stage, and a steady increase stage. However, unlike coal, alkane and alkene gases produced by oil shale underwent four stages. They all had a concentration reduction stage with the maximum drop of 24.20%. Statistical classification of inflection temperature of various gases as their concentrations change showed that the temperature of 140 °C is the key temperature for group reactions, and above the temperature of 140 °C, all alkane and alkene gases underwent the rapid concentration increase stage.

show abstract

Experimental analysis of the combustion characteristics of Estonian oil shale in air and oxy-fuel atmospheres

Cited by 37 publications

References 28 publications

Pyrolysis and char oxidation characteristics of oil shales and coal in a thermogravimetric analyzer

Pyrolysis and char oxidation characteristics of oil shales and coal in a thermogravimetric analyzer

Ash and Flue Gas from Oil Shale Oxy-Fuel Circulating Fluidized Bed Combustion

Study on Low Temperature Oxidation Characteristics of Oil Shale Based on Temperature Programmed System

Contact Info

Product

Resources

About