Opportunities for Improving Energy and Environmenta Performance of China’s Cement Kilns
This report examines 22 technologies or measures that can be used to retrofit or toreplace older, inefficient cement kilns to improve their energy efficiency. Suchtechnologies can help China achieve two goals, often erroneously believed to be inconflict: (1) reduce energy use and pollution; and (2) maximize the industry's economicperformance and output. The barrier to their implementation is not the lack ofeconomically feasible technology, but rather the lack of a mechanism to financeinvestment and outreach to the cement and financial sectors.
Fourteen of the technologies and measures examined have simple payback periods ofthree years or less. At the current price of carbon, sale of associated carbon credits wouldyield an additional $1,300 – $850,000 on top of the energy cost savings (ranging from 0to 3.4 GJ/t of fuel and -11 to 35 kWh of electricity), assuming the Clean DevelopmentMechanism requirements could be met.
China produces roughly half of the world's cement, most of which is made in energyinefficient, highly polluting kilns. The cement industry is a major source of multiple airpollutants, among them dioxins and dioxin-like chemicals, mercury, particulate matterand greenhouse gas emissions.
Production of clinker, the main ingredient of cement, consumes about 80% of the energyused at a cement plant. Clinkering is also the source of almost all carbon dioxide andtoxic emissions produced from cement manufacture, including several persistentbioaccumulative toxics that can be transported inter-continentally. This report providesinformation related to retrofitting cement kilns in China with technologies and measuresto improve energy efficiency and to reduce greenhouse gas emissions as well as effectiveparticulate control technologies.
In 2005, just over one billion tons of cement were produced in China. Cement demandwill continue to be high in the near future as development goals are pursued. Cementproduction is expected to peak at 1,250 Mt in the 2010-2011 period and then begin toslowly decline.
Cement production facilities are found in every province and autonomous region ofChina. At the end of 2004, there were 5027 cement producers in China that owned over14,000 cement kilns and employed 1.4 million workers. Prices continued to rise in 2004.In the first quarter of 2004 profits increased by 63.95% compared with the same period ofthe last year.
In recent years, the Chinese cement industry has experienced domestic reorganizationthrough mergers and acquisitions as well as an increase in foreign investment. Large cement companies have all expanded through mergers and acquisitions. Foreign investorssuch as Holcim, Lafarge, and Heidelberg Cement are acquiring shares in domesticfacilities and Lafarge has built cement factories in Beijing, Chengdu, and Chongqing.
While many energy-efficiency improvement opportunities exist at all stages of cementproduction, this report focuses on technologies and measures for improving the energyefficiency of the kiln itself, as well as product and feedstock changes which will also resultin reduction of fuel consumed in the kiln. In addition, the report describes case studieswhere measures have been implemented in China and, where data are available, what thecosts and savings would be upon implementation. The report notes whether thetechnologies are available in China as domestic or foreign imports. For some domestically-produced technologies and measures, although the cost can be much lower, theperformance of a domestic technology might be inferior in energy efficiency to importedtechnologies. There are a number of domestic cement equipment manufacturers in China.Some foreign companies have set up branches in China to provide equipment, while forother technologies, some components are imported but then assembled in China,potentially with other parts manufactured domestically.
The analysis of cement kiln energy-efficiency opportunities is divided into technologiesand measures that are applicable to all kilns, those that are only applicable to rotary kilns,those that are only applicable to vertical shaft kilns, and product and feedstock changes thatwill reduce energy consumption for clinker making. Most measures reduce fuelconsumption in the kiln, which is the focus of this report. Some measures reduce kiln fuelconsumption while also reducing electricity consumption. A few measures applicable tocement kilns only reduce electricity consumption. While these measures are not the focusof this report, they have been included in order to provide a comprehensive overview of theenergy-efficiency opportunities for cement kilns. Details on each energy-efficiencytechnology and measure, including a description, case studies, and data are provided.