CO2 emissions from cement industry in China: A bottom-up estimation from factory to regional and national levels

doi:10.1007/s11442-017-1402-8

Abstract

Abstract:

Much attention is being given to estimating cement-related CO₂ emissions in China. However, scant explicit and systematical exploration is being done on regional and national CO₂ emission volumes. The aim of this work is therefore to provide an improved bottom-up spatial-integration system, relevant to CO₂ emissions at factory level, to allow a more accurate estimation of the CO₂ emissions from cement production. Based on this system, the sampling data of cement production lines were integrated as regional- and national-level information. The integration results showed that each ton of clinker produced 883 kg CO₂, of which the process, fuel, and electricity emissions accounted for 58.70%, 35.97%, and 5.33%, respectively. The volume of CO₂ emissions from clinker and cement production reached 1202 Mt and 1284 Mt, respectively, in 2013. A discrepancy was identified between the clinker emission factors relevant to the two main production processes (i.e., the new suspension preheating and pre-calcining kiln (NSP) and the vertical shaft kiln (VSK)), probably relevant to the energy efficiency of the two technologies. An analysis of the spatial characteristics indicated that the spatial distribution of the clinker emission factors mainly corresponded to that of the NSP process. The discrepancy of spatial pattern largely complied with the economic and population distribution pattern of China. The study could fill the knowledge gaps and provide role players with a useful spatial integration system that should facilitate the accurate estimation of carbon and corresponding regional mitigation strategies in China.

Key words: China, cement industry, CO2 emissions, bottom-up estimation, spatial integration

Yan YANG, Limao WANG, Zhi CAO, Chufu MOU, Lei SHEN, Jianan ZHAO, Yebing FANG. CO₂ emissions from cement industry in China: A bottom-up estimation from factory to regional and national levels[J].Journal of Geographical Sciences, 2017, 27(6): 711-730.

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Data types	Data indexes	Data sources
Production data from cement plants	The production-line scale of enterprises; Annual clinker and cement production	Field survey
	Annual consumption of coal; Annual consumption of electricity (including waste-heat power deduction)	Field survey
	Weighted-average lower heating value (LHV) of coal; Coal fuel- moisture content	Field survey
	Full chemical composition and individual proportion of raw meal/coal/ clinker (annual average); Each material ratio in raw meal (annual average)	Field survey
Socioeconomic data	GDP per capita	China Statistical Yearbook (2014)
Cement industry data	Technical level; Investment level; Scale level, Profit level; Total clinker output; Total cement output	China Cement Almanac (2012- 2014); China Industry Information Network (2014a, 2014b, 2014c)
Geological data	Partitions of cement-with-limestone reserves and quality	The Information Center of the MLR (Ministry of Land and Resources of the PRC); CBMA (China Building Materials Academy)
Geological data	Partitions of coal quality	The Institute of Coal Chemistry, Chinese Academy of Sciences; Chen, 2009

Process types	Units of clinker emission sources	Number (valid samples)	Max	Min	Difference	Average	Mean square deviation
Process types	Units of clinker emission sources	Number (valid samples)	kg/t	kg/t	kg/t	kg/t	Mean square deviation
NSP process	Process emissions	164	556	478	78.83	520	14.28
	Fuel emissions	162	391	261	129.24	312	26.51
	Electricity emissions	161	98	14	83.28	46	20.73
VSK process	Process emissions	64	529	392	137.52	501	20.76
	Fuel emissions	59	548	286	262.73	351	60.18
	Electricity emissions	63	114	37	76.32	59	15.79

Indicators and their calculating methods	Explanations
${{R}_{carbonate\text{ }calcination\text{ in raw }meal}}=R{{a}_{c{{o}_{2}}}}\times {{r}_{a}}\times 1000$$R{{a}_{c{{o}_{2}}}}=\sum{\left( Rc{{a}_{i}}\times {{r}_{i}}\times \frac{44}{56}+Rm{{g}_{i}}\times {{r}_{i}}\times \frac{44}{40} \right)}\ (i=1,2,3\ldots )$${{r}_{a}}\frac{1-{{C}_{cl}}\times {{A}_{c}}}{1-{{R}_{l}}}$	$R{{a}_{c{{o}_{2}}}}$ is the CO₂ content in the raw meal (%); r_a is the raw meal-to-clinker ratio (t/t clinker); Rca_i and Rmg_i are respectively the calcium carbonate and magnesium carbonate content in the raw material i (%); r_iis the share of the raw material i in the raw meal (%); 44/56 and 44/40 are respectively the CO₂ content in calcium carbonate and magnesium carbonate; C_cl is the coal consumption (dry) for producing a unit of clinker (t/t clinker); A_c is the ash content of coal (%); R_l is the loss on ignition of the raw meal (%).
${{R}_{flue\text{ }gas\text{ }dust\text{ }in\text{ }kiln-head}}=\frac{{{R}_{carbonate\text{ }calcination\text{ in }raw\text{ }meal}}\cdot {{U}_{e}}}{1000}$	U_e is the amount of flue gas dust emissions per ton clinker in the cement kiln-head (kg/t clinker).
${{R}_{bypass\text{ }dust}}=\frac{{{Q}_{d}}\cdot {{B}_{e}}}{1000}$ ${{B}_{e}}={{R}_{carbonate\text{ }calcination\text{ in raw }meal}}\cdot \left( 1-\frac{{{R}_{b}}}{{{R}_{l}}} \right)$	Q_d is the quantity of bypass dust per ton of clinker production (kg/t clinker); B_e is the CO₂ emissions from the bypass dust in producing a unit of clinker (kg/t clinker); R_b is loss on ignition of the bypass dust (%).

Regions	Process emission factors		Fuel emission factors		Electricity emission factors
Regions	Mean	Standard deviation	Mean	Standard deviation	Mean	Standard deviation
Xinjiang	525	22.34	346	23.55	79	9.30
Heilongjiang	516	20.65	304	22.70	39	14.47
Jilin	516	20.65	294	44.59	39	14.47
Hebei	520	16.83	312	44.18	39	14.33
Beijing	520	22.34	243	22.70	60	22.44
Tianjing	520	22.34	294	25.09	53	25.83
Liaoning	516	20.65	296	22.70	60	22.44
Ningxia	527	27.11	313	36.33	55	20.47
Shandong	520	20.65	307	25.30	46	16.04
Shaanxi	524	14.08	313	36.33	54	25.83
Shanxi	527	27.98	309	35.82	58	22.12
Qinghai	528	28.39	305	36.33	49	21.41
Gansu	527	21.81	313	36.33	55	23.51
Henan	520	16.67	312	24.62	47	18.52
Jiangsu	516	20.28	276	23.25	30	13.08
Tibet	528	28.39	311	40.42	55	24.07
Anhui	519	13.88	312	24.36	30	12.89
Chongqing	520	19.63	303	51.50	55	20.72
Hubei	518	16.77	305	36.33	54	20.89
Sichuan	522	13.69	304	51.33	53	25.11
Jiangxi	525	13. 50	305	35.82	38	7.60
Guizhou	515	21.23	311	38.95	44	20.11
Hunan	518	16.77	305	36.33	55	23.46
Yunnan	520	16.99	321	40.42	55	24.07
Guangxi	524	14.08	315	40.42	48	24.07
Shanghai	520	22.34	253	25.09	47	18.88
Hainan	520	16.99	311	40.42	49	21.41
Zhejiang	520	16.99	266	23.67	30	13.08
Fujian	528	16.33	302	5.10	34	15.07
Guangdong	524	14.08	305	36.33	37	7.93
Inner Mongoria	520	22.34	305	36.33	60	22.44

Regions	Process emission factors		Fuel emission factors		Electricity emission factors
Regions	Mean	Standard deviation	Mean	Standard deviation	Mean	Standard deviation
Xinjiang	526	4.94	338	0.72	83	8.67
Northeast China and eastern Inner Mongoria	514	12.97	305	12.41	47	13.08
Beijing, Tianjing, Hebei	519	10.10	299	15.98	42	13.83
Shandong	520	14.14	306	15.25	46	15.28
Shaanxi	521	11.69	314	28.41	55	24.18
Shanxi and central Inner Mongoria	527	13.13	314	28.41	55	20.17
Gansu, Ningxia, and western Inner Mongoria	526	6.88	314	28.41	50	13.45
Henan, Anhui	518	8.98	312	28.68	41	11.51
Shanghai, Zhejiang, and Jiangsu	524	9.67	304	18.01	29	6.73
Tibet, Qinghai	528	20.55	316	21.78	46	14.83
Sichuan, Chongqing	519	9.58	304	18.18	54	18.89
Guizhou	515	14.71	321	28.56	44	17.98
Yunnan	518	15.33	321	29.66	52	21.17
Fujian	527	14.52	303	9.13	34	15.54
Guangdong, Guangxi, and Hainan	519	12.73	316	21.06	42	8.43
Hunan, Hubei, and Jiangxi	518	9.28	314	28.41	46	10.88

CO₂ emissions from cement industry in China: A bottom-up estimation from factory to regional and national levels

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Regions	Portland clinker output (2013)	Cement output (2013)	Process emission factors	Fuel emission factors	Electricity emission factors	Clinker emission factors	Grinding emission factors	Clinker emissions (2013)	Cement emissions (2013)
Regions	Mt	Mt	kg CO₂/t	kg CO₂/t	kg CO₂/t	kg CO₂/t	kg CO₂/t	Mt CO₂	Mt CO₂
Northeast China	78	145	511	309	47	867	40	68	73
Northern China	126	259	521	314	50	885	38	112	122
Eastern China	369	674	521	310	36	867	25	320	337
Central China	242	483	515	313	50	877	34	213	229
Southern China	159	261	519	322	42	883	35	140	150
Southwest China	247	375	515	324	51	890	36	220	233
Northwest China	140	217	523	336	67	925	49	129	140
National NSP	1195	-	520	313	45	879	34	-	-
National Shaft	167	-	503	348	60	912	36	-	-
National Compositive	1362	2414	518	318	47	883	34	1202	1284

Process types		Process emission factors	Fuel emission factors	Electricity emission factors	Clinker emission factors
NSP process	Emission factors (kg CO₂/t clinker)	520	313	45	879
NSP process	Proportion in clinker emissions (%)	59.20	35.65	5.15	59.20
VSK process	Emission factors (kg CO₂/t clinker)	503	348	60	912
VSK process	Proportion in clinker emissions (%)	55.22	38.18	6.60	55.22
Gaps of the two	(kg CO₂/t clinker)	-16.93	34.72	14.97	32.76

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Regions	Standard deviation
	Process emission factors		Fuel emission factors		Electricity emission factors
	Sandwich	Simple random	Sandwich	Simple random	Sandwich	Simple random
Northeast China	15.74	17.52	13.79	18.72	12.61	15.75
Northern China	7.16	14.45	16.91	33.59	12.94	22.76
Eastern China	8.51	16.78	10.10	21.32	6.37	16.88
Central China	9.86	11.58	21.47	22.22	9.44	18.24
Southern China	12.72	7.22	21.01	17.35	8.48	16.07
Southwest China	8.10	14.29	18.48	32.08	12.96	21.88
Northwest China	5.23	12.11	16.64	18.01	8.48	25.09