【作者】 周和敏；

【导师】 左铁镛； 聂祚仁；

【作者基本信息】 北京工业大学 ， 材料学， 2001， 博士

【摘要】 生命周期评价——作为一种重要的环境特性评价方法和企业环境管理工具,目前还没有建立起能够为人们普遍接受的实用模型方法。本文将这种系统评价工具应用于钢铁生产过程的环境行为分析,提出了钢铁生产环境协调性评价问题。针对钢铁生产过程实际情况,提出了生产过程环境协调性评价的目标、边界条件、指标体系以及调研编目分析框架,建立了评价指标体系的数学模型。在钢铁生产流程分析的基础上,确立了流程与资源消耗、能耗及废弃物排放的框架模型,通过对几种工艺流程的数据收集处理,得到环境负荷编目分析结果。按照本文提出的环境负荷累积对比模型,计算出不同流程工序产品的环境负荷综合指数,并对环境协调性评价的结论进行进一步解释。本文详细分析了我国钢铁工业的资源消耗和环境状况。针对我国钢铁生产矿物资源和能源消耗过大、环境污染问题十分突出的现状,本文指出,通过改进原料结构和能源消费结构,加强环境排放控制和管理,有利于较大幅度地减少污染物的发生量和排放量。文中对我国钢铁工业未来十年间气体污染物排放、废水排放和固体废弃物排放总量进行了评估。本文针对我国目前尚未建立钢铁生产环境排放总量控制模型和标准的现状,根据复杂系统的特点和评价要求,运用灰色系统理论方法,建立了灰色综合评价模型,并对钢铁生产企业环境排放进行分类,可为我国钢铁企业吨钢环境排放分类标准的建立提供参考。本文对钢铁生产工序的环境排放因子与国内重点钢厂进行统计学对应分析,清晰地表明钢铁生产各工序环境因子变量的相关程度和钢厂的分类情况,同时也指出了各钢厂受哪些环境因子变量影响和控制。本文根据国内钢铁生产的特点,提出了环境负荷的综合相对环境指数IREI,在此基础上建立了具有可对比性、可定量化的钢铁生产环境负荷累积对比模型,并应用到国内几种典型的钢铁生产流程评价中。同时提出了模型权值的动态系数权值法和统计关联权值法的概念,并对权值进行了计算。结果表明:与高炉-转炉流程相比,直接还原铁具有较明显的环境优势;以废钢为原料的电炉钢普钢流程的环境负荷也明显小于高炉/转炉流程。鉴于国际上对CO₂ 温室效应日益重视,目前对评价CO₂ 排放标准化的问题已提到议事日程上来。本文从环境协调性评价的观点出发,针对钢铁生产的几种流程,在研究的系统边界内进行编目分析和评价。结果表明:对于吨铁产品累计CO2排放量,直接还原海绵铁最大,高炉铁次之,熔融还原铁最小;对于吨钢产更多还原

【Abstract】 Life cycle assessment is a powerful tool in the evaluation of the environmental impact of manufacturing processes and environmental management. However, there hasn’t been a methodology that can be widely accepted. On the basis of the life cycle approach in combination with iron and steel processes, the purpose of the study and the system boundaries are defined and the indexes for life cycle assessment of iron & steel processes are set up. The life cycle inventory of resources and energy uses and environmental releases are complied. The integrated index of environmental impact is defined and an integrated comparative model is established. The indexes are compared with each other for several production routes of iron & steel process. The results of the life cycle assessment are analyzed and the improvement countermeasures are given for iron & steel process. In this paper, the resource consumptions and environmental conditions in the steel industry have been discussed in detail. As a large amount of natural resources and energy is consumed in steel-making and a great many pollutants are generated, pollution problems resulting from steel-making stand out. It is also pointed out that it is necessary to reduce the quantity of waste generation and emission by improving the raw material and energy structure, and reinforcing the waste control and management. Furthermore, the total emissions of waste gas, wastewater and waste solid are forecast during the next decade. Up to now the standard and control model for environmental discharge of iron & steel production have not been set up in China. According to the characteristics of complex system and the requirement of environmental assessment, a gray model for integrated assessment is introduced in this paper. It is important and beneficial for the set up of classification and the control standard of waste-discharge per ton steel for Chinese steel industry. The correspondence analysis is one of the methods in statistics. With this method, the environmental factors are analyzed for key iron & steel companies in the present thesis. The co-relativities among environmental factors and the classification of iron & steel Co. can be reasonably obtained. At the same time, it is clarified that each steel Co. is affected and controlled by different crucial factors. Based on the characteristics of the iron and steel processes in China, Integrated relative environmental index (IREI) is defined and a new accumulative comparative model for life cycle assessment is established, which is applied to the assessment of several typical iron and steel processes, such as DRI/EAF process and BF/BOF process. In addition, the concepts of dynamic correlated weighting and statistical correlated weighting are defined. It is shown that the results from this method could be quantitatively compared with each other. The case studies show that the environmental performance of the DRI/EAF process is superior to that of the BF/BOF process. Furthermore, the production of EAF-steel made from scraps has obviously more environmental advantages than that of BF/BOF process. After Tokyo greenhouse prevention conference (COP3 )a lot of countries and governments are struggling to reduce CO2 emissions. From the viewpoint of LCA, the life cycle inventories of CO2 emissions for several flows of iron and steel making are studied, and the results are shown as follows: the accumulative CO2 emissions per ton DRI are more than those of BF-iron and molting reduction iron; the accumulative CO2 emissions per ton crude steel for BF/BOF process are more than those of DRI/EAF process and EAF process; the CO2 emissions concentrate on the processes before iron-making, therefore how to reduce energy consumption before iron-making is the key to reducing CO2 emissions. From the viewpoint of sustainable development, the optimization to product structure and the complete manufacturing process, which is environment friendly, will be one of the strategic goals in Chinese steel industry. A whole procedure of cleaner production is the main measure for “Green manufacture”. The paper presents the results of environmental impact assessment on cleaner production of iron and steel processes, and moreover the model of fuzzy multiple criteria decision for environmental impact improvement. It provides the reference for improving assessment. With the economic benefits as optimal goal and environmental impact as constraints, optimal programming for structure of iron & steel products is performed. Based on combining the environmental impact assessment with integrated economic benefits, it helps to apply the results of environmental impact assessment to the practical use. According to the methods of ISO14040 and《ECO-indicator 99 methodology report》, the damages to mineral and fossil resources, to ecosystem quality, and to human health of Chinese steel industry are discussed in this thesis. The results show that these damages have decreased obviously since 1990. In terms of the relationship of mineral resource consumption, energy consumption, environmental performance and technical economy for Chinese steel industry, the assessment index and its index system for sustainable development are presented. The results show that the efficiency of resources-economy, environmental-economy and sustainable development are non-steadily increasing. In the end, conclusions of the thesis and further clues for research are given.更多还原