北京地区水泥行业的物能代谢及其环境影响

Material-Energy Metabolism and Environmental Implications of Cement Industry in Beijing

利用物质流分析方法,对北京地区水泥生产和使用过程的物能代谢及其环境影响进行研究。水泥生产过程物能代谢的时间序列分析表明,从1949至2002年,水泥产量呈加速增长的趋势,对区域生态系统产生了巨大的扰动。水泥生产过程环境影响的主要表现包括占用和破坏土地资源;消耗大量的矿质原料和能源;排放CO2;造成环境酸化、人体健康损害和环境富营养化。水泥生产和使用过程物能代谢的空间格局分析显示,水泥产量和水泥生产过程环境负荷的空间差异非常显著。由于产地与使用地分布格局的明显错位,以及外地水泥的大量调入,2001年水泥运输过程中的能源消耗与该年本地水泥生产过程中的能源消耗大致处于同一水平。在水泥最终产品混凝土的生产过程中,2001年的砂石消耗量及其生态包袱的总和是该年本地水泥生产过程资源和能源消耗量及其生态包袱总和的4·2倍。由此可见,只有将物质流分析贯穿水泥生产和使用的全过程,才能比较客观地揭示出水泥行业物能代谢及其环境影响的实际情况。

Cement industry is one of the largest natural resource and energy consumers and pollution sources in Beijing,reducing resource and energy consumption and pollutant emission in cement production and usage has been turned out to be an important measure to improve regional ecological and environmental quality. The study aims to reveal spatial and temporal characteristics of material-energy metabolism and environmental impacts of the cement industry, and to provide countermeasures for regulating distribution of cement industry and enhancing environmental performance of cement products. Material flow analysis was used for this study. Time series analyses show that the output and environmental load of cement industry in Beijing has gone through three stages over past 54 years （ 1949 - 2002）. Since 1991, cement output increased rapidly, which induced severe environmental disturbance and huge resource consumption. Most important impacts of cement production on the ecosystem were damage of land resources and depletion of mineral resources. Followed by CO2 emission and energy consumption. Although the quota of dust, smoke, SO2, and NOx in the total environmental load was small, its impact on air pollution, human health and eutrophication were severe. In order to promote environmentally harmonious development in cement industrial sector, the principal measures include reducing mineral dosages, improving burning technology, and enhancing energy efficiency. In terms of spatial patterns of cement production and usage, regional difference in cement output and environmental load was very significant. Since the major cement consumption areas are away from the production areas and the amounts of imported cement from other provinces are huge, additional energy consumption in cement transportation has to be considered. According to a rough estimation, such energy consumption accounted for 97 % of total energy consumption of Beijing in 2001. Therefore, transportation is an important factor affecting environment in cement usage. In concrete production, significant environmental impact occurs in the exploitation of gravel and sand. The sum of gravel and sand consumption and their ecological rucksack for the concrete production reached 4.2 times of that of resource and energy consumption and their ecological rucksack for cement production in Beijing in 2001. This shows that material flow analysis of cement should include the whole process of cement production and usage in order to reflect the reality of material-energy metabolism and environmental impacts of the cement industry.