1. Oil shale combustion under oxyfuel conditions
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3rd International Conference and Expo on
Oil and Gas
July 13-14, 2017 Berlin, Germany
Oil shale combustion under oxyfuel conditions
Leema Al-Makhadmeh
Al-Hussein Bin Talal University,
Jordan University of Science and Technology,
Jordan

2. Presentation Outline Introduction Oxyfuel Combustion Experimental Part
Results and Discussion
Conclusions
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3. 12/4/2018
Introduction
Jordan is a non-oil producing country and is largely affected by the world energy situation; it has a clear plan for oil-shale utilizations.
Oil-shale resources in Jordan are estimated to be 40 billion tons, in which the oil is about 4 billion tons.
Oil shale utilization in Jordan and elsewhere faces many obstacles that affect its utilization.
Oil shale combustion under oxyfuel conditions was investigated in this study in a trial to solve some of the challenges that faces Jordanian oil shale combustion.
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4. Oxyfuel Combustion
Oxyfuel combustion, a combination of oxygen, with a purity of more than 95%, and recycled flue gas is used for combustion of the fuel.
H2O
CO2 recovery
Boiler
ASU
air N2 O2
Fuel
Recirculated flue gas
CO2 storage
CO2, H2O,…
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5. Experimental Part
El-Lajjun oil-shale from south of Jordan was used in this study. The following table shows the detailed analysis of oil shale .
Oil shale combustion was performed in a vertical 20- kW furnace (see the following Fig).
Both unstaged and staged combustion experiments were performed in air and OF27 condition.
The wall temperature during all the combustion experiments was 1200°C.
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6. El-Lajjun oil-shale analysis
Proximate Analysis
Water (ar, %)
1.08
Ash (wf, %)2
54.20
Volatile (waf, %)3
99.06
Fixed carbon (waf, %)
0.85
Ultimate Analysis
C (waf, %)
55.68
H (waf, %)
4.27
N (waf, %)
0.87
S (waf, %)
8.30
O (diff, %)5
30.88
LHV (waf, kJ/kg)
D90 (µm)
35.3
1: as received
2: water free
3: water ash free
4: by difference
5 Di: represent that i% by volume of the particles that have a diameter equal to or less than Di.
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7. A once-through vertical 20 kW furnace
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8. Results and Discussion
Oil shale behavior during unstaged combustion
Axial concentration profiles of oxygen, carbon monoxide, nitrogen oxide and sulphur dioxide for air-firing and OF27 combustion (excess O2 = 3%, T = 1200◦C).
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9. Oil shale emission during unstaged combustion
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Oil shale emission during unstaged combustion
NO and SO2 emissions and their conversions during air-firing and OF27 combustion at the exit of the reactor for El-Lajjun oil shale combustion.
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10. Oil shale behavior during staged combustion
Air-firing
OF27 combustion
Axial concentration profiles of O2, CO, and NO for staged air-firing and OF27 combustion (λ=0.75, T = 1200 ◦C, 2 m far from the burner).
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11. Reduction of NO emissions using staged combustion
Air-firing
OF27 combustion
NO emissions and Oilshale-N conversion over burner oxygen ratio under air-firing and OF27 combustion.
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12. Reduction of simulated recycled NO during undstaged and staged combustion
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13. In-furnace limestone addition during unstaged combustion
Air-firing
OF27 combustion
SO2 emissions and the efficiency of desulphurization during unstaged air-firing and OF27 combustion (Ca/S ratios=1, 2, and 3)
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14. In-furnace limestone addition during unstaged combustion
Fig. 3. SO2 emission during unstaged and staged air-firing and OF27 combustion, limestone
molar ratio is Ca/S=2 for staged combustion and for unstaged1, unstaged2 without limestone addition. Position of staged probe is 2 m from the burner.
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Conclusions
During OF27 combustion, the CO concentration in the burner section is much higher than air-firing due to the gasification reactions in a CO2-rich medium.
Even though, there is almost no problem for CO controlling for OF27 combustion as well as air-firing.
Oxidant staging was used efficiently for NO reduction from oil shale combustion in both modes.
Oil-shale N conversion to NO at the exit of the furnace during unstaged mode and with oxygen burner ratio of 0.95 is lower for OF27 combustion compared to air-firing.
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During unstaged and staged air-firing and OF27 combustion, the simulated recycled NO is efficiently reduced.
The simulated recycled NO reduction is more efficient during staged OF27 combustion than unstaged case.
El-Lajjun oil shale- S conversion rates to SO2 is 69% and 49% for air-firing and OF27 combustion, respectively.
By using direct in furnace limestone injection, SO2 emission was reduced significantly in both unstaged and staged OF27 and air-firing as well.
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17. The desulfurization efficiency was affected by the oxidant-stage level, Ca/S molar ratio and position of the secondary oxidant.
The desulfurization efficiency for oil shale combustion in staged air-firing and in staged OF27 combustion ranged from 32 to 61% and from 25 to 60%, respectively.
The desulfurization efficiency during unstaged combustion was much higher than that during staged combustion.
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18. Thank you 3rd International Conference and Expo on Oil and Gas
July 13-14, 2017 Berlin, Germany
Thank you
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