↑↑钢铁企业余热资源的回收与利用↑↑↑↑↑↑↑↑↑ ↑

↑↑↑ ↑↑ ↑↑↑↑－－再论我国钢铁工业的节能方向与途径↑
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↑↑蔡九菊↑↑  ↑↑东北大学↑↑↑↑↑↑↑↑↑ ↑

↑↑（已在《钢铁》↑2007.06↑期发表）↑↑↑↑ ↑
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↑↑摘↑↑  ↑↑要↑↑↑：↑↑↑剖析了自↑↑↑1980↑↑↑年以来国内钢铁企业吨钢可比能耗的下降趋势，总下降率↑↑↑48%↑↑↑，其中直接节能↑↑↑56%↑↑↑，间接节能↑↑↑44%↑↑↑，但仍比国外先进产钢国高出↑↑↑112kgce/t↑↑↑。查明国内生产↑↑↑1↑↑↑吨钢产生余热资源量↑↑↑8.4GJ/t↑↑↑钢，目前回收利用的仅占↑↑↑25.8%↑↑↑，高效回收利用余热资源是未来钢铁工业节能的主攻方向。论述了热平衡法、↑火用↑分析法、能级分析法及其相关效率指标的局限性，指出余热回收利用环节所在工序产品能耗的改变量是评价热工装备完善性和过程系统用能合理性的统一判据。依据热力学第一、第二定律推导了与热效率和能级差相关联的↑火用↑效率表达式，用↑火用↑效率和产品能耗改变量等评价指标比较了若干典型余热回收技术的优劣，给出了它们中的推荐模式及其节能效果。↑↑↑↑↑↑↑ ↑

↑↑关键词↑：↑↑↑ ↑↑钢铁工业；↑余热回收；↑火用↑分析；↑热平衡；↑能级↑↑↑↑ ↑
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↑↑Recovery of Residual-Heat Resources in Integrated Steelwo↑rks↑↑↑↑↑ ↑

↑↑↑↑c↑↑AI↑↑↑ ↑↑j↑iu-ju↑↑↑ ↑No↑rtheastern↑ ↑University↑↑↑↑ ↑
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↑↑↑↑Abstract:↑↑↑↑ ↑↑↑Downtrend of energy consumption per ton crude steel in China steel industry is analyzed a↑nd the energy intensity has been reduced by 48%, in which 56% is obtained by directly energy saving a↑nd 44% indirectly. However, ↑↑↑↑↑↑↑↑China↑↑↑↑ steel industry still consumes 112kgce/t mo↑re energy compared with the advanced countries. The residual-heat resource of ↑↑↑China↑↑↑’s steel industry has been calculated to be 8.4GJ/t-s, in which only 25.8% is recovered, so residual-heat recovery will play an impo↑rtant role in energy saving of ↑↑↑↑China↑↑↑↑ steel industry in the future. The limitations of heat balance analysis, exergy analysis, energy level analysis a↑nd related efficiency indicato↑rs are discussed. The variation of energy consumption per ton product of the process where the residual-heat is recovered is actually the criterion to evaluate the perfection of thermotechnical equipments a↑nd rationality of energy utilizing in process systems. Based on the first a↑nd second law of thermodynamics, the expression of exergy, co↑rrelated with heat efficiency a↑nd energy level difference, is deduced. Exergy efficiency a↑nd variation of energy consumption per ton product have been used as the evaluating indicato↑rs↑ ↑to analyze the current technologies fo↑r recovery of typical residual-heat in steel industry, a↑nd the reasonable way of residual-heat recovery a↑nd its energy saving effect is indicated.↑↑↑↑↑↑ ↑

↑↑↑↑Key wo↑rds:↑↑↑ steel industry; waste heat recovery; exergy analysis; heat balance; energy level.↑↑↑↑↑↑↑↑↑↑ ↑