5.1 Proximate analysis and Ultimate analysis of Coal

 IS: 1350-1 (1984): Methods of Test for Coal and Coke, Part I: Proximate Analysis [PCD 7: Solid Mineral Fuels]

	PROXIMATE ANALYSIS OF COAL ( EXAMPLE)
A	Surface Moisture
	Method	100 gm sample kept in open space for 2 hours
	Sample Weight	SW	gm	100
	Before Weight	BW	gm	100
	After weight	AW	gm	95
	% SM =	(BW-AW)*100/SW	%	5
B	Inherent Moisture
	Method	200 micron size sample kept in 108 ± 2 ᵒC for 1 hour. Lignite starts decomposing at a temperature below 100 ᵒC, so Dean & stark apparatus is used.
	Sample Weight	SW	gm	10
	Before Weight	BW	gm	10
	After weight	AW	gm	9.7
	% IM =	(BW-AW)*100/SW	%	3
C	ASH
	Method	1 gm sample kept in 900 ᵒC for 1 hour in furnace.
	Sample Weight	SW	gm	1
	Crusible Weight	CW	gm	5
	After weight	AW	gm	5.05
	Q	AW - CW	gm	0.05
	% ASH =	Q*(1-IM/100)*100/SW	%	4.85
D	Volatile Matter
	Method	1 gm sample kept in 900 ± 15 ᵒC for 7 hour. IS 1350 part I:1984, part III, IV.
	Sample Weight	SW	gm	1
	Before Weight	BW	gm	1
	After weight	AW	gm	0.75
	% VM =	(BW-AW)*100/SW	%	25
E	Fixed Carbon
	% FC =	100-(IM+VM+ASH)	%	67.15
F	GCV
	Method 1 =	(154*(100 - (1.1*Ash+IM)) - 108*IM)/1.8	Kcal/Kg	7662.5
	Method 2 =	(165*FC + 138(VM-0.1*Ash)) - 108*IM)/1.8	Kcal/Kg	7854.9

Difference between ultimate analysis and proximate analysis:

	Ultimate analysis	Proximate analysis
1	It is the chemical analysis to determine the  percentage of carbon, hydrogen, nitrogen, sulphur and occasionally Phosphorus and chloride	It is the chemical analysis to determine the percentage of moisture, volatile matter, ash and fixed carbon.
2	Concentration of carbon hydrogen oxygen required in classification of coal and in in combustion calculation	Classification of coal on the basis of volatile metal matter percentage and calorific value
3	Concentration of chloride, V are vital in considering the problem of corrosion and boiler deposit	Cold drink depends on moisture low rank high moisture
4	Sulphur and phosphorus determine the metallurgy of iron and steel	Volatile matter determines the Furnace volume and arrangement of heating surface
5	C+H+O+N+S+M+A=100%	FC+VM+M+A=100%

	RELATIONSHIP BETWEEN PROXIMATE ANALYSIS  AND ULTIMATE ANALYSIS (Example)
A	Proximate analysis (ADB)			Lab Report	Calculated
	Fixed Carbon	FC	%	67.15
	Ash	A	%	4.85
	Volatile Matter	VM	%	25
	Moisture	M	%	3
	Carbon	C = 0.97FC+ 0.7(VM - 0.1A) – M(0.6–0.01M)	%		80.586
	Hydrogen	H = 0.036FC + 0.086 (VM–0.1xA) - 0.0035M2 (1–0.02M)	%		4.4961
	Nitrogen	N2 = 2.10 – 0.020 VM	%		1.6
	Total moisture	TM	%	13.1
	Gross Calorific Value	GCV	Kcal/Kg	3364
B	Proximate Analysis (As Fired Basis)
	Conversion factor from ADB to AFB ( X = (100- Total Moisture)/(100-air dried moisture)				0.90
1	Moisture	Total moisture ARB	%		13.10
2	Ash	AFB = ADB x Conversion Factor	%		4.34
3	Volatile Matter		%		22.40
4	Fixed Carbon		%		60.16
C	Conversion to Ultimate analysis
	Free carbon on Dry ash free basis	FcDc(T)=FC/{1-(1.1*A/100)-(M/100)}	%		73.26
	Volatile Matter  on Dry ash free basis	VmDf(T)=(100-FcDc(T))	%		26.74
	Fixed carbon on dry ash free basis	Cdf(T)={FcDc(T)+0.9*(VmDf(T)-14))	%		84.73
	Hydrogen On Dry Ash Free Basis	Hdf(T)=VmDf(T)*{(7.35/VmDf(T)+10)-0.013)	%		5.00
	Nitrogen on dry ash free basis	Ndf(T)={2.1-(0.012*VmDf(T)}	%		1.78
	Ultimate analysis
	Carbon	C = Cdf(T)*({VM+FC}/{VmDf(T)+FcDc(T)}	%		69.95
	Hydrogen	H2 = Hdf(T)*{VM+FC}/{VmDf(T)+FcDc(T)}	%		4.13
	Nitrogen	N2 = Ndf(T)*{VM+C}/{VmDf(T)+FcDc(T)}	%		1.47
	Sulfur	S	%		0.60
	Oxygen	O2 = 100-M-A-C-H-N-S	%		6.41
D	Theoretical Air =	[(11.6 x C) + {34.8 x (H2 - O2/8)} + (4.35 x S)]/100	Kg/Kg of Fuel		9.30