Goal and technology path of CO sub(2) mitigation in China's cement industry: from the perspective of co-benefit

• Published in: Journal of cleaner production Vol. 114; pp. 299 - 313
• Main Authors: Tan, Qilu, Wen, Zongguo, Chen, Jining
• Format: Journal Article
• Language: English
• Published: 15.02.2016
• Subjects: Air pollution; Carbon dioxide; Cements; China; Dust; Dust control; Energy consumption; Reduction; China, People's Rep
• ISSN: 0959-6526
• DOI: 10.1016/j.jclepro.2015.06.148

The concept of co-benefit, a negotiation topic in CO sub(2) mitigation attracts worldwide attention including China in coping with climate change. Energy saving technologies as common measures for CO sub(2) abatement, generally lead to co-benefits of local air pollution (LAP) because most LAP emissions are generated from combustion of carbonic fuels along with CO sub(2). However, in the technological dimension, there are technologies that induce opposite effects on the co-benefit of CO sub(2) and LAP in specific industry sectors. Precalcinating line and shaft kiln, two types of technologies adopted in clinker calcinating procedure in cement industry are examples: the former consume less energy but emit more dust and NO sub(x) than the later. As a result, the overall co-benefits of LAP reductions for cement industry are uncertain. This study consequently aims at assessing the overall co-benefit (although it may be a negative co-benefit) of CO sub(2) mitigation policy on dust, NO sub(x), SO sub(2) emissions in China's cement industry aggregately by establishing bottom-up optimization model on the basis of all types of technologies which are called technology system in cement production. CO sub(2) mitigation goal, as represented by reduction rate is regarded as constraint input into the model. In order to investigate the evolution of co-benefits and technology paths with the change of CO sub(2) mitigation goal, hundreds of reduction rates are selected randomly between the range 0.5-10.5%. The lower bound 0.5% reveals CO sub(2) emission reduction that can be reached for cement industry under existing political constraints and without any extra CO sub(2) mitigation goal. The upper bound 10.5% is the greatest reduction rate under which the model could derive feasible solution. According to changes of technology penetration rates as CO sub(2) goal tightens, we could evaluate the more cost-effective technologies from the perspective of co-benefit. They are vertical milling, precalcinating line with the scale of 7000-10,000 ton/day, roll-squeezer belonging to Main Production Technology (MPT), utilization of cement grinding aids, multi-channel coal burner belonging to Affiliated Energy-saving technology (AES), combination of bag-filter and electrostatic precipitator and ultra-low NO sub(x) burning technology belonging to Pollution Control Technology (PCT). With respect to the evolution of co-benefits on air pollutions, when the CO sub(2) reduction rate is below 2.3%, co-benefit of dust and SO sub(2) reduction exist while that of NO sub(x) does not; and when the rate is above 2.3%, co-benefits of all the three pollutants exist. A practically referable goal of CO sub(2) mitigation rate of short/mid-term is approximately 5.5% in view of the following three considerations: a) co-benefits augment as CO sub(2) reduction rate increases; b) total cost increases as the CO sub(2) abatement goal becomes stricter; and c) the majority of emerging technologies normally cannot penetrate to 100% in cement production within a relatively short time.