Since the 1970s, the studies on the geography of enterprise have become increasingly concerned with the spatial evolution of an enterprises in the West developed countries. However, little attention has so far been g...Since the 1970s, the studies on the geography of enterprise have become increasingly concerned with the spatial evolution of an enterprises in the West developed countries. However, little attention has so far been given to the spatial evolution of an enterprise in China. With China's ongoing economy and political reforms, a number of fundamental changes of enterprise behavior have occurred. These changes have certainly important influences on the evolution of industrial location. Therefore, there is a need for examining the spatial evolution of an enterprise in China. The purpose of the paper is to review the mapjor models of both the growth,and associated spatial evolution of an enterprise, with an illustrative case study of the HeaVy Automobile Enterprise Group of China. The paper is organized by three parts. The first examines the spoilal groWth and location adjustment of multi-plant enterprise. The second reviews mapjor models of the spatial evolution of an enterprise. And the third analyzes the spatial evolution, over a period of time, of a representative sample of the Heavy Automobile Enterprise Group of China, and illustrates the findings with case studies. It is suggested that the models of spatial evolution of an enterprise would provide more evidence about micro-mechanism for evolution of micro- regional economic systems.展开更多
Heat exchanger networks(HENs)in separated plants can be simultaneously synthesized through process streams directly or intermediate fluids indirectly.However,the direct and indirect methods are studied separately in m...Heat exchanger networks(HENs)in separated plants can be simultaneously synthesized through process streams directly or intermediate fluids indirectly.However,the direct and indirect methods are studied separately in most existing researches.As the result,conventional designs are probably suboptimal,because optimal solutions may call for hybrid approach wherein direct and indirect integration methods are used synchronously.To circumvent this drawback aforementioned,we propose in this research a novel methodology to synthesize multi-plant HENs considering both direct and indirect approaches.The methodology employs a novel superstructure covering most potential topologies for both interplant and intra-plant heat integration.We also take into account multiple kinds of intermediate fluids for indirect integration and this has not been fully addressed in previous research.A mixed-integer nonlinear programming(MINLP)is formulated to optimize multi-plant HENs involving indirect and direct methods.One example from existing literature and one industrial problem are solved to demonstrate the methodology’s capability.展开更多
为兼顾“双碳”目标与能源保供底线,提升能源系统源荷侧降碳能力,在有效挖掘系统降碳潜能的同时,缓解火电装机总量增长与风电消纳之间的矛盾,文章将绿氨生产、氨煤混燃以及多种灵活性资源结合构成绿氨耦合发电单元,同时考虑碳捕集等低...为兼顾“双碳”目标与能源保供底线,提升能源系统源荷侧降碳能力,在有效挖掘系统降碳潜能的同时,缓解火电装机总量增长与风电消纳之间的矛盾,文章将绿氨生产、氨煤混燃以及多种灵活性资源结合构成绿氨耦合发电单元,同时考虑碳捕集等低碳技术,并应用碳排放流理论,提出了考虑绿氨替代与多元阶梯碳势需求响应的综合能源虚拟电厂(integrated energy virtual power plant,IEVPP)低碳经济调度模型,以降低系统碳排放并提升系统经济性。首先,将绿氨替代作为解决风电供用能不匹配问题的手段,并将其与燃煤机组掺氨技术结合,分析其能量流动与低碳特性;其次,将电-碳-氢-氨多元耦合过程引入IEVPP,从而促进了风电消纳,提升了系统调节能力;最后,依托碳排放流理论,通过动态碳排放因子提出了多元阶梯碳势需求响应模型,从源荷两侧充分挖掘系统降碳潜能。算例仿真分析结果表明,所构建的考虑绿氨替代IEVPP联合多元阶梯碳势需求响应可有效降低系统碳排放量,提升系统经济性。展开更多
为提升虚拟电厂(virtual power plant,VPP)参与电力市场的经济性与调控协调性,提出一种基于分层分区调控的虚拟电厂市场多时间尺度竞价策略。首先,定义虚拟机组作为调度与交易统一建模单元,依据电网拓扑结构与过载风险构建分区聚合策略...为提升虚拟电厂(virtual power plant,VPP)参与电力市场的经济性与调控协调性,提出一种基于分层分区调控的虚拟电厂市场多时间尺度竞价策略。首先,定义虚拟机组作为调度与交易统一建模单元,依据电网拓扑结构与过载风险构建分区聚合策略,进一步构建其外特性表征模型以反映虚拟电厂可调节能力。其次,建立涵盖日前与实时市场的多时间尺度竞价模型,并利用库恩-塔克(Karush-Kuhn-Tucker, KKT)条件将其转化为单层优化问题以降低求解复杂度。最后,通过算例验证所提模型的有效性。结果表明,该策略可在保障网络安全与隐私保护的基础上,有效降低建模维度;可实现VPP在多时间尺度市场中的协调竞价,与采用固定报价和仅考虑日前市场相比,VPP收益分别提升了15.8%和17.2%,增强了VPP的市场适应能力与收益水平。展开更多
文摘Since the 1970s, the studies on the geography of enterprise have become increasingly concerned with the spatial evolution of an enterprises in the West developed countries. However, little attention has so far been given to the spatial evolution of an enterprise in China. With China's ongoing economy and political reforms, a number of fundamental changes of enterprise behavior have occurred. These changes have certainly important influences on the evolution of industrial location. Therefore, there is a need for examining the spatial evolution of an enterprise in China. The purpose of the paper is to review the mapjor models of both the growth,and associated spatial evolution of an enterprise, with an illustrative case study of the HeaVy Automobile Enterprise Group of China. The paper is organized by three parts. The first examines the spoilal groWth and location adjustment of multi-plant enterprise. The second reviews mapjor models of the spatial evolution of an enterprise. And the third analyzes the spatial evolution, over a period of time, of a representative sample of the Heavy Automobile Enterprise Group of China, and illustrates the findings with case studies. It is suggested that the models of spatial evolution of an enterprise would provide more evidence about micro-mechanism for evolution of micro- regional economic systems.
基金Financial supports from the National Natural Science Foundation of China(No.21476256)Science Foundation of China University of PetroleumBeijing(Nos.2462017BJB03&2462018BJC004)are gratefully acknowledged.
文摘Heat exchanger networks(HENs)in separated plants can be simultaneously synthesized through process streams directly or intermediate fluids indirectly.However,the direct and indirect methods are studied separately in most existing researches.As the result,conventional designs are probably suboptimal,because optimal solutions may call for hybrid approach wherein direct and indirect integration methods are used synchronously.To circumvent this drawback aforementioned,we propose in this research a novel methodology to synthesize multi-plant HENs considering both direct and indirect approaches.The methodology employs a novel superstructure covering most potential topologies for both interplant and intra-plant heat integration.We also take into account multiple kinds of intermediate fluids for indirect integration and this has not been fully addressed in previous research.A mixed-integer nonlinear programming(MINLP)is formulated to optimize multi-plant HENs involving indirect and direct methods.One example from existing literature and one industrial problem are solved to demonstrate the methodology’s capability.
文摘为兼顾“双碳”目标与能源保供底线,提升能源系统源荷侧降碳能力,在有效挖掘系统降碳潜能的同时,缓解火电装机总量增长与风电消纳之间的矛盾,文章将绿氨生产、氨煤混燃以及多种灵活性资源结合构成绿氨耦合发电单元,同时考虑碳捕集等低碳技术,并应用碳排放流理论,提出了考虑绿氨替代与多元阶梯碳势需求响应的综合能源虚拟电厂(integrated energy virtual power plant,IEVPP)低碳经济调度模型,以降低系统碳排放并提升系统经济性。首先,将绿氨替代作为解决风电供用能不匹配问题的手段,并将其与燃煤机组掺氨技术结合,分析其能量流动与低碳特性;其次,将电-碳-氢-氨多元耦合过程引入IEVPP,从而促进了风电消纳,提升了系统调节能力;最后,依托碳排放流理论,通过动态碳排放因子提出了多元阶梯碳势需求响应模型,从源荷两侧充分挖掘系统降碳潜能。算例仿真分析结果表明,所构建的考虑绿氨替代IEVPP联合多元阶梯碳势需求响应可有效降低系统碳排放量,提升系统经济性。
文摘为提升虚拟电厂(virtual power plant,VPP)参与电力市场的经济性与调控协调性,提出一种基于分层分区调控的虚拟电厂市场多时间尺度竞价策略。首先,定义虚拟机组作为调度与交易统一建模单元,依据电网拓扑结构与过载风险构建分区聚合策略,进一步构建其外特性表征模型以反映虚拟电厂可调节能力。其次,建立涵盖日前与实时市场的多时间尺度竞价模型,并利用库恩-塔克(Karush-Kuhn-Tucker, KKT)条件将其转化为单层优化问题以降低求解复杂度。最后,通过算例验证所提模型的有效性。结果表明,该策略可在保障网络安全与隐私保护的基础上,有效降低建模维度;可实现VPP在多时间尺度市场中的协调竞价,与采用固定报价和仅考虑日前市场相比,VPP收益分别提升了15.8%和17.2%,增强了VPP的市场适应能力与收益水平。
