Oil Shale Pulverized Firing: Boiler Efficiency, Ash Balance and Flue Gas Composition

Konist, Alar; Pihu, T.; Neshumayev, Dmitri; Siirde, Andres

doi:10.3176/oil.2013.1.02

Cited by 19 publications

(11 citation statements)

References 14 publications

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“…The specific emission of CO 2 for PC and CFB is 974 g CO 2 /kWh and 872 g CO 2 /kWh, respectively. The specific emission of SO 2 for PC and CFB is 11.89 g SO 2 /kWh and zero, respectively [31,32].…”

Section: Introductionmentioning

confidence: 97%

Calculation of the Amount of Estonian Oil Shale Products From Combustion in Regular and Oxy-Fuel Mode in a CFB Boiler

Konist¹,

Loo²,

Valtsev³

et al. 2014

Oil Shale

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Oxy-fuel combustion is considered as one of the promising carbon capture and storage (CCS) technologies for coal-fired boilers. In oxy-fuel combustion, the combustion gases are oxygen and the recirculating flue gas, and the main components of the combustion gas are O 2 , CO 2 and H 2 O [1]. The paper presents the results of the calculation of the flue gas amount during combustion of oil shale using oxy-fuel technology in a circulated fluidized bed (CFB) mode. The calculations were performed for different oil shale heating values and different recycled flue gas (RFG) ratios. Oxy-fuel combustion with flue gas recycling was found to enable the decrease of the extent of carbonate minerals decomposition (ECD), thereby increasing the amount of heat released per 1 kg of fuel. To minimize ECD, the recycled flue gas ratio should be maintained at a level higher than 0.7. This condition allows an increase of the partial pressure of CO 2 over the equilibrium state line of calcite decomposition reaction at the bed temperature. The decrease of ECD was observed up to CO2-min 0.28. k = The decrease of CO2 k leads to an additional increase in the amount of heat released during oil shale combustion per 1 kg and, depending on the mean lower heating value (LHV), the heat can be increased up to 0.34 MJ/kg. A comparison with the bituminous and anthracite coals revealed that the specific emission of CO 2 per input fuel energy for oil shale is expected to be even smaller compared with those of the considered coals.

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Section: Introductionmentioning

confidence: 97%

Calculation of the Amount of Estonian Oil Shale Products From Combustion in Regular and Oxy-Fuel Mode in a CFB Boiler

Konist¹,

Loo²,

Valtsev³

et al. 2014

Oil Shale

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“…During stable CFB combustion, the sulfur oxides level in the flue gas was low. When the ash circulation was stopped (see Figure 3), the sulfur concentration in the flue gas increased to a level above typical oil shale PC boilers [45].…”

Section: Comparison With Utility Scalementioning

confidence: 94%

“…The oil shale used in the experiments was room dry. Normally, the oil shale used in the industry has a moisture content slightly over 10% [11,45].…”

Section: The Oil Shalementioning

confidence: 99%

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

et al. 2018

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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.

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“…China has the world's second largest resources of oil shale, which are estimated at 1600 million barrels [7]. As the reduction of sulphur emissions and sulphur content in shale oil are regulated by legislation and have therefore received considerable attention [8][9][10], the precise determination of sulphur content in the fuel used is of high importance worldwide. The properties of oil shales are highly dependent on their geographical location.…”

Section: Introductionmentioning

confidence: 99%

Determination of the Total Sulphur Content of Oil Shale by Using Different Analytical Methods

Maaten¹,

Pikkor²,

Konist³

et al. 2018

Oil Shale

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This paper presents the results of determination of the total sulphur content of Estonian and Chinese oil shales (OS) by using different analytical methods-elemental analysis, quantitative chemical analysis and X-ray fluorescence spectroscopy (XRF). The different forms of sulphur and respective quantities were determined in order to offer a possible explanation to the discrepancy between the results. Thermogravimetric analysis coupled with mass spectrometry (TGA-MS) was used as an additional tool to verify the release of SO 2 and confirm the existence of sulphur in the organic and mineral parts of oil shale. Different analysis methods established different sulphur contents for the samples, showing a strong relationship between the sample composition and the analysis result. For both Estonian and Chinese oil shales the highest total sulphur content values, 1.53 and 2.23%, respectively, were determined using elemental analysis. As expected, the values were highly dependent on analysis conditions: the mass of sample and amount of catalyst used. The total sulphur contents of Estonian and Chinese oil shale samples as determined by the quantitative chemical analysis were 1.2 and 2.01%, respectively. Surprisingly, for Chinese oil shale the total sulphur content found by the quantitative chemical analysis was lower than that established by XRF. XRF determined the total sulphur contents of Estonian and Chinese oil shales to be 1.2 and 2.19%, respectively. These results suggest that elemental analysis should be the preferred method for the determination of total sulphur content.

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Oil Shale Pulverized Firing: Boiler Efficiency, Ash Balance and Flue Gas Composition

Cited by 19 publications

References 14 publications

Calculation of the Amount of Estonian Oil Shale Products From Combustion in Regular and Oxy-Fuel Mode in a CFB Boiler

Calculation of the Amount of Estonian Oil Shale Products From Combustion in Regular and Oxy-Fuel Mode in a CFB Boiler

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

Determination of the Total Sulphur Content of Oil Shale by Using Different Analytical Methods

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