Paper presented at the SEGRM 2018 Symposium

1. Physicochemical, Microstructural,
Mineralogical and Thermal Properties of
Owukpa Coal for Future Power
Generation
By
Bemgba B. Nyakuma (MSc)
SEGRM Symposium on Geo-engineering (SEGRM-GEO) at Universiti Teknologi
Malaysia, Kuala Lumpur, 3rd to 4th July, 2018

2. Co-Authors
Edo O. Ojoko (MSc),
Olasunkanmi O. Olapeju (MSc),
Olagoke A. Oladokun (PhD)

3. Presentation Outline
Introduction
Experimental
Results & Discussion
Conclusions
Acknowledgment
References

4. Introduction
 Coal is a combustible brownish to
black sedimentary rock.
 Occurs as stratified rock(s) in layers
called coal beds or seams
 Most widely abundant and accessible
source of fossil energy worldwide.
 Wide applications in electricity,
cement, chemicals & steel
manufacturing

5. Introduction
 Coal significantly contributes to socio-
economic growth and development,
particularly in India & China.
 Coal helped address energy poverty in the
BRICS particularly South Africa with 77% of
electricity generation.
 South Africa’s success & the discovery of
large new deposits have revived interest in
Nigeria’s coal industry.
Source: https://bit.ly/2lTHvPc

6. Introduction
 Nigeria is Africa’s largest economy & mos
populous nation
 Plagued by power problems  electricity
penetration is low >> 57% access to
uninterrupted access.
 Est. 640 million tonnes of proven coal
reserves & 3 billion inferred >> lower,
middle & upper Benue trough.
 Consists 49% sub-bituminous, 39%
bituminous, & 12% lignite coals

7. Introduction
 Despite the potential, coal power generation is
non-existent, depriving Nigerians of an
abundant, & accessible energy source.
 Coal power generation in Nigeria is plagued by
vast challenges >> technological, socio-
economic & geopolitical
 Lack of physicochemical, thermal, kinetic &
thermodynamic data of Nigerian coals required
for power plants.
Source: https://bit.ly/1KvtQDa
Source: https://sie.ag/2KIzWFL

8. Aim of Study
 Large coal deposits are unutilized in Benue (Owukpa),
Nasarawa (Shankodi-Jangwa), Plateau (Barkinladi) &
Enugu (Amansiodo), despite the large scale
manufacturing, mining & agriculture potential.
 Therefore, this study will examine the physicochemical,
microstructural, mineralogical & thermal properties of
Owukpa coal for future power generation in Nigeria.

9. Experimental
 Extensive characterization was performed by ultimate
(elemental), proximate & calorific analyses.
 Functional group analysis was examined by Fourier Transform
Infra-Red (FTIR) spectroscopy.
 Microstructural & mineralogical was examined by Scanning
Electron Microscopy/Energy Dispersive X-ray (SEM/EDX).

10. Experimental
 Thermal degradation behaviour was examined by non-
isothermal thermogravimetric analysis (TGA).
 Characteristic profile temperatures (TPC) were examined by
TG-DTG Plots analysis using TGA Software.
 Flash conversion conditions (50 °C/min from RT-900 °C) under
N2 & Air were applied to simulate pulverized coal combustion
(PCC) in power plants.

11. Results & Discussion > Physicochemical Analysis
 Owukpa >> high C, H, & O with
compositions; 65.40 wt%, 5.23 wt% &
27.32 wt%, respectively.
 Composition of the pollutant elements N
& S were; 1.60 wt% & 0.46 wt%.
 Calorific value of Owukpa was 26.67 MJ/kg
 It is a subbituminous, non-agglomerating,
& low-rank coal (LRC).
Element Symbol
wt.%
composition
Carbon C 65.40
Hydrogen H 5.23
Nitrogen N 1.60
Sulphur S 0.46
Oxygen O 27.32
Moisture M 6.50
Volatile matter V 31.49
Fixed Carbon FC 41.78
Ash A 20.23
Heating Value HHV 26.67

12. Results & Discussion > Microstructure & Mineralogy
 Microstructure of Owukpa is a
heterogeneous mix of fine &
coarse-grained particles rich in
organic & metallic elements.
 Major elements detected by EDX
analysis were; carbon (C = 82.74
wt%), oxygen (O = 15.29 wt%),
silicon (Si = 0.90 wt%) & aluminum
(Al = 0.43 wt%).
Element Symbol Wt%
Carbon C 82.74
Oxygen O 15.29
Silicon Si 0.90
Aluminum Al 0.43
Sulphur S 0.40
Iron Fe 0.18
Titanium Ti 0.06

13. Results & Discussion > Thermal Analysis
0
10
20
30
40
50
60
70
80
90
100
110
0 100 200 300 400 500 600 700 800 900 1000
TG(%)
Temperature (°C)
WKP-FPY
-2.5E-02
-2.0E-02
-1.5E-02
-1.0E-02
-5.0E-03
0.0E+00
0 100 200 300 400 500 600 700 800 900 1000
DTG(%/min)
Temperature (°C)
WKP-FPY
TG Plots for Flash Pyrolysis (FPY) &
Flash Combustion (FCO)
DTG Plots for Flash Pyrolysis (FPY) &
Flash Combustion (FCO)

14. Results & Discussion > Thermal Analysis
 TGA analysis revealed that flash combustion (FCO) of
Owukpa resulted in 77.41% mass loss.
 However, flash pyrolysis (FPY) of Owukpa resulted in
42.09% mass loss.
 Hence, solid or residual mass yields for FCO and FPY were;
22.59% and 57.91%, representing ash & coke, respectively.

15. Results & Discussion > Thermal Analysis
Temperature Profile
Symbol Flash Pyrolysis
(FPY)
Flash Combustion
(FCO)
Drying Peak TDpk 116.48 116.17
Tpeak Tmax 487.41 495.84
Onset TOns 339.06 274.56
Midpoint TMid 469.41 519.47
Offset TOff 617.25 759.23
Characteristic Temperature Profiles

16. Conclusions
 Owukpa contains high proportions of combustible elements, & low
pollutant precursor elements.
 Proximate analysis revealed low moisture & volatiles but high ash, fixed
carbon & calorific value.
 Microstructure & mineralogy revealed metal elements which can be
beneficial as catalysts during thermal conversion.
 Thermal analyses revealed flash combustion is more thermally efficient
for energy recovery from Owukpa.
 Owukpa is may be suited for electric power generation or cement
manufacture.

17. Acknowledgement
The authors wish to acknowledge the support of Dr Tuan Amran
Tuan Abdullah and the Hydrogen Laboratory, Institute of
Hydrogen Energy, Universiti Teknologi Malaysia (UTM),
Skudai Campus. Many thanks also accrue to Mr Adakole B.
Aboje of Ehinehi Nigeria Enterprises Limited, Federal Capital
Territory, (FCT Abuja), Nigeria for supplying the Owukpa coal
sample.

18. References
1. IEA, Market Series Report: IEA Coal 2017 in Analysis and Forecasts to
2022. 2017, International Energy Agency: Paris, France. p. 1-8.
2. Nyakuma, B.B., et al., Evaluating the Energy Recovery Potential of
Nigerian Coals under Non-Isothermal Thermogravimetry. IOP
Conference Series: Materials Science and Engineering, 2017. 217(1): p.
012013.
3. Shahbaz, M., A.K. Tiwari, and M. Nasir, The effects of financial
development, economic growth, coal consumption and trade openness
on CO2 emissions in South Africa. Energy Policy, 2013. 61: p. 1452-1459.
4. WorldBank. Access to electricity (% of the population) - The case of
Nigeria. 2018; Available from https://bit.ly/2Ih1b8L.