Characteristics of Fundamental Combustion and NO_x Emission Using Various Rank Coals

Figures & data

Figure 1. Schematic diagram of the combustion system.

Table 1. Physical analysis for various coals

Coals (country)	NAR	Total H2O	H2O	FC	VM	Ash	C	H	O	N	S	Ash	Rank
Anthracite (CHN)	3040	5.02	3.3	40.42	10.74	45.54	47.37	1.27	2.56	0.14	1.56	47.1	Anthracite
Anglo (IND)	6515	13.77	3.85	49.29	30.89	15.97	73.73	4.43	2.98	1.71	0.54	16.61	Bituminous
C&A (Austria)	6417	7.52	4.01	49.42	31.31	15.26	72.77	4.29	4.9	1.63	0.51	15.9	Bituminous
Berau (Austrua)	6155	23.61	12.04	42.56	39.68	5.72	68.70	5.23	17.58	1.5	0.49	6.5	Sub-bituminous, lignite
Shinwha (China)	6673	13.11	8.53	50.75	34.92	5.8	75.77	4.85	11.58	1.15	0.31	6.34	Sub-bituminous, lignite
SM (India)	5304	26.34	12.6	40.16	42.7	4.54	52.03	5.21	26.5	0.92	0.15	5.19	Sub-bituminous, lignite
KBB1 (India)	896	34.21	15.73	44.81	38.01	1.45	46.34	3.85	21.89	0.62	0.01		Sub-bituminous, lignite
KBB9 (India)	584	26.53	12.46	16.82	51.71	19.01	38.73	3.9	20.87	0.66	0.01		Sub-bituminous, lignite
Notes: NAR = net as received; VM = volatile matter; FC = fixed carbon.

Table 2. Combustion characteristics of each coal using TGA and morphological analysis of coals

Coals	T v (°C)	T f (°C)	Activation E (kJ/mol)	VM/(VM + FC)	Total H2O	Pore Volume (cm^3/g)	Pore Size (nm)	DTG Peak Temperature (°C)
Anthracite	310	630	197.713	0.20993	5.02	0.0069	10.717	655
C&A	327	615	137.6152	0.387836	7.52	0.0100	15.105	578
Anglo	300	610	107.289	0.385258	13.77	0.0181	11.940	572
Shinwha	300	850	46.19678	0.407611	23.61	0.0170	6.2043	661
Berau	250	550	59.71546	0.48249	13.11	0.0109	22.821	498
SM	250	490	82.29758	0.515327	26.34	0.0223	26.133	397
KBB1	250	510	52.27732	0.458947	34.21	0.0282	23.926	488
KBB9	250	490	59.33303	0.75456	26.53	0.0209	17.220	451
Notes: VM = volatile matter; FC = fixed carbon.

Figure 2. TGA for non-isothermal combustion of various coals.

Figure 3. DTG profiles (a) and Arrhenius plot (b) through the TGA for various coals.

Figure 4. Outlet NO concentration on coal combustion according to feeding flows used B1 combustion (coal: 0.2 g).

Figure 5. Released fuel N to N₂ intensity on coal combustion according to temperatures using B1 combustion [coal: 0.2 g of C&A coal; flow: various (21% O₂/Ar)].

Figure 6. Mechanism of NO_x formation and reduction.

Table 3. Volatile matter contents and the NO emission characteristics of various coals

Coals	Volatile N to NO/Total N to NO	VM/(VM + FC)
Anthracite	0.2922	0.20993
C&A	0.3743	0.387836
Anglo	0.5314	0.385258
Shinwha	0.6282	0.407611
Berau	0.3643	0.48249
SM	0.8333	0.515327
KBB1	0.74126	0.458947
KBB9	0.65049	0.75456
Notes: VM = volatile matter; FC = fixed carbon.

Figure 7. Outlet NO (mg) on coal and char combustion according to treated temperatures using B1 combustion (coal: 0.2 g of coals, 21% O₂/Ar 1 L/min).

Figure 8. The correlation between volatile N to NO/fuel N ratio to NO and VM/(VM + FC) (a) and H₂O contents (b) in various coals.