Construction of Environmentally Benign Regional Energy System by Cascade Use of Waste Energy

本研究的目的是研究废热在钢铁、水泥、造纸和乙烯等能源密集型行业中梯级利用的潜力。首先，在日本当地的实际产业结构中，对热梯式区域节能潜力进行了评估。其次，在Conbinat模型中引入了产业的空间约束，便于区域节能评价。第三，从节约成本潜力和节能潜力的角度，提出了考虑能源使用质量的新的经济激励措施，称为能源税和能源税退税。本文的主要研究成果概括如下：1.热力梯级节能潜力高度依赖于当地产业结构。乙烯高温余热供应与纸、纸浆的中低温热电需求之间的级联，可提供较高的节能效果。通过优化产业结构，蒸汽锅炉实现能量平衡的油耗可降低90%以上。在优化组合中，换热损失对节能潜力的影响不大。当大量的热传递损失不可避免时，将废能转化为电能是可取的。从节能潜力的角度来看，经济激励是提高节能潜力的有效手段。“能源税”考虑到能源使用的质量，比能源税更经济地促进了热力梯级的引入。基于(火用)效率的“能源税退税”比“能源税”更实用，它可以实现与从节能角度优化的成本和油耗几乎相同的成本和油耗。

The purpose of this research is to investigate the potential of cascade use of waste heat among energy intensive industries : iron & steel, cement, paper & pulp and ethylene. Firstly, regional energy-saving potential by heat cascading was evaluated in the actual local industrial structure in Japan. Secondly, spatial constrains of industries were introduced in the conbinat model to facilitate the evaluation of regional energy-saving. Thirdly,from the viewpoints of cost-saving potential as well as the energy-saving potential, new economic incentives, referred to as "energy tax" and "energy-tax refund", were proposed in consideration of the quality of energy use. Main results obtained in this paper are summarized as follows :1. Energy-saving potential by heat cascading highly depends on local industrial structure.2. Cascading between high temperature waste heat supply of ethylene and middle & low temperature heat and electricity demand of paper & pulp can provide high energy-saving.3. Oil consumption of steam boilers for the energy balance in a combinat can be reduced by more than about 90% by optimizing the industrial structure.4. Heat transmission loss will give little influence to the energy-saving potential in the optimized combinat.5. The conversion of waste energy into electricity is preferable, when considerable heat transmission loss is unavoidable.6. Economic incentives are effective to increase the energy-saving potential in the combinat optimized from the viewpoint of cost-saving potential.7. "Energy tax" in consideration of the quality of energy use promotes the introduction of heat cascading more economically than energy tax.8. "Energy-tax refund" based on exergy efficiency is more practical than "Energy tax", which can accomplish almost the same cost and oil consumption optimized from the cost-saving viewpoint as those optimized from the energy-saving viewpoint.