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通过理论分析及现场测试 ,分析了过量空气系数对注汽锅炉热效率的影响 ,得出了在注汽锅炉实际运行中应加强对过量空气系数的监控 ,使过量空气系数降低 ,从而提高注汽锅炉热效率的结论 相似文献
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河北省高速公路衡大筹建处 《交通节能与环保》2011,(4):8-11
高速公路收费站、服务区一般远离市区、城镇,不便接入市政集中供热系统,须独立设置供热与制冷系统。地源热泵空调系统是一项先进的空调技术,利用大地温度相对恒定的特性,解决了冬季采暖、夏季制冷问题,属可再生能源利用技术,与采用锅炉(煤、油、电)供暖+分体空调制冷方式相比较,系统简单,运行费用低,降低能耗,不污染环境,节能、环保效果显著。 相似文献
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BZJ皮带机是煤二期预留煤炭堆场重要的设备,驱动单元由3台功率为280KW的电机组成。经过多年使用和试运行,在满足设备启动、运行的情况下,采用三机启动双机运行改造,并运行半年至今,效果良好。本文分别从改造原理和节能数据进两方面进行了探讨。 相似文献
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船舶供油单元燃油原来是由燃油/废气组合锅炉提供蒸汽加热,船舶正常负荷航行时,加热介质由废气锅炉产生蒸汽能满足加热燃油之需,停航与锚泊时由燃油锅炉产生蒸汽来满足燃油加热之需。供油单元加装辅助电加热装置后,船舶停航与锚泊时,在一定时间内(5~6天)由电加热装置替代燃油锅炉;在船舶航行期间,降速航行而导致废气锅炉蒸汽不足时由电加热替代锅炉燃烧产生加热介质保证燃油的温度,保证船舶正常航行,从而节约船舶能耗。 相似文献
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在电厂系统运行时,阀门及管道法兰处容易发生泄漏,影响机组的安全可靠运行。夹具带压堵漏技术可实现机组的不停机检修。结合现场大量的实践应用,介绍了带压堵漏技术的工作原理、研究现状、操作中的关键技术。通过该技术在某电厂的应用,总结出影响堵漏成功的主要因素,针对夹具设计中的不足,提出了夹具改进的方法及新型螺栓带压堵漏工具的设计方法,提高了堵漏成功率。 相似文献
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长输天然气管道压气站场控制由站场控制系统和压缩机控制系统组成,两部分控制系统通过通讯连接将数据传输至调控中心和站场PLC,但站控系统和压缩机控制系统、压缩机控制系统和辅助系统相互独立,这是目前压气站场控制的普遍模式。通过将单台压缩机组与相应辅助系统控制进行整合、与全部机组相关的生产辅助系统同站控系统进行整合,整合后的压气站场由原有的三部分控制调整为站控系统PLC统一监视控制。控制系统整合将分散的控制功能集中,站场内全部设备实现远程操作,数据、故障集中监视方便问题处理,同时减少了冗余设备。 相似文献
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Adaptive Cruise Control systems have been developed and introduced into the consumer market for over a decade. Among these systems, fully-adaptive ones are required to adapt their behaviour not only to traffic conditions but also to drivers’ preferences and attitudes, as well as to the way such preferences change for the same driver in different driving sessions. This would ideally lead towards a system where an on-board electronic control unit can be asked by the driver to calibrate its own parameters while he/she manually drives for a few minutes (learning mode). After calibration, the control unit switches to the running mode where the learned driving style is applied. The learning mode can be activated by any driver of the car, for any driving session and each time he/she wishes to change the current driving behaviour of the cruise control system.The modelling framework which we propose to implement comprises four layers (sampler, profiler, tutor, performer). The sampler is responsible for human likeness and can be calibrated while in learning mode. Then, while in running mode, it works together with the other modelling layers to implement the logic. This paper presents the overall framework, with particular emphasis on the sampler and the profiler that are explained in full mathematical detail. Specification and calibration of the proposed framework are supported by the observed data, collected by means of an instrumented vehicle. The data are also used to assess the proposed framework, confirming human-like and fully-adaptive characteristics. 相似文献
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Carlos F. Daganzo Gordon F. Newell 《Transportation Research Part B: Methodological》1985,19(5):397-407
This paper studies the costs involved in distributing items from a warehouse or depot to randomly scattered customers on a day-to-day basis. Two trade-offs are explored simultaneously. The first one arises because by accumulating large inventories at the depot it is possible to build more efficient distribution tours. This trade-off has already been explored for both distribution of goods (Burns et al., 1983) and passengers (Daganzo et al., 1977; Hendrickson, 1978). Another tradeoff, which involves the length of individual vehicle tours (Clarens and Hurdle, 1975), balances the inventory inside the vehicles against the transportation cost. Banks et al. (1982) have considered both of these tradeoffs simultaneously in the context of passenger transportation, but used a somewhat unrealistic model for vehicle routing. This paper is similar to the latter reference but uses a different routing strategy. It also illustrates how the nature of the objects carried (cheap goods, expensive goods, people, etc.) affects the optimal configuration of the distribution system and the overall distribution costs. Usually there is an optimum partitioning of the service area into districts and an optimum dispatching frequency in each district. The results can vary tremendously, depending on factors such as: the inventory carrying cost per item per unit time, the transportation costs, the demand per unit area and unit time, the average distance from the depot, the average vehicle speed and the time per stop.As an illustration of the ideas, a hypothetical limousine service from an airport is analyzed. The example is used to demonstrate how dramatically the optimal system configuration depends on the nature of the items carried. 相似文献
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通过采用变频调节阀,配合PLC的软件编程,能够使甲醇精馏工艺控制系统的调节阀在一个高水平状态下运行。变频调节阀是采用变频器主回路的电动调节阀,并通过改变节流方式来控制流量,所以它既是一种有效的调节手段,同时又是一个节流节能、降低环境污染的部件,很值得在相关企业推广使用。 相似文献
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This paper compares and assesses fuel consumption models, cost functions, and solution methods, as they all have an influence on the resulting profile and associated fuel savings of an eco-cruise control system for passenger vehicles. An eco-cruise control system uses road topographical data obtained from a high-resolution digital map to control the vehicle velocity to optimize its fuel consumption. The optimal velocity profile is the result of an optimal control problem. 相似文献
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This paper presents a fuel efficient control strategy for a group of connected hybrid electric vehicles (HEVs) in urban road conditions. A hierarchical control architecture is proposed in this paper for every HEV, where the higher level and the lower level controller share information with each other and solve two different problems that aim at improving its fuel efficiency. The higher level controller of each HEV is considered to utilize traffic light information, through vehicle to infrastructure (V2I) communication, and state information of the vehicles in its near neighborhood, via vehicle to vehicle (V2V) communication. Apart from that, the higher level controller of each HEV uses the recuperation information from the lower level controller and provides it the optimal velocity profile by solving its problem in a model predictive control framework. Each lower level controller uses adaptive equivalent consumption minimization strategy (ECMS) for following their velocity profiles, obtained from the higher level controller, in a fuel efficient manner. In this paper, the vehicles are modeled in Autonomie software and the simulation results are provided in the paper that shows the effectiveness of the proposed control architecture. 相似文献
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《Transportation Research Part A: General》1986,20(6):415-427
The results of statistical analysis of cross-sectional and longitudinal public transport operating statistics from 16 countries aimed at identifying the relationships between subsidy, on the one hand, and fares, service, passengers, unit costs and output per employee on the other, are reported. This study updates earlier work carried out in 1979 for the European Conference of Ministers of Transport, and uses a greatly expanded data set covering 117 individual cities in 11 countries, and aggregate national data from 16 countries, over the period 1965–1982. The statistical correlations identified between year-on-year changes in subsidy and changes in a wide range of operating indicators show that the subsidy has reduced fares and increased the amount of service operated, and each extra 1% of cost covered by subsidy probably attracts a 0.2 to 0.4% increase in passengers. However, the study also finds highly significant relationships between increases in subsidy, on the one hand, and increases in unit costs and wages and reductions in output per employee, on the other. It seems that as much as one half of subsidy has been consumed by higher costs and time-lagged regressions suggest that, in part, the increases in unit cost tend to follow subsidy rather than precede it, giving some cause for concern that the uses of subsidy are not being controlled as tightly as they might. 相似文献
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Perimeter control based on the Macroscopic Fundamental Diagram (MFD) is widely developed for alleviating or postponing congestion in a protected region. Recent studies reveal that traffic conditions might not be improved if the perimeter control strategies are applied to unstable systems where high demand generates heavy and heterogeneously distributed traffic congestion. Therefore, considering stability of the targeted traffic system is essential, for the sake of developing a feasible and then optimal control strategy. This paper sheds light on this direction. It integrates a stability characterization algorithm of MFD system equations into the Model Predictive Control (MPC) scheme, and features respectively an upper and a lower bound of the feasible control inputs, to guarantee system stability. Firstly, the dynamics of traffic heterogeneity and its effect on the MFD are analyzed, using real data from Guangzhou in China. Piecewise affine functions of average flow are proposed to capture traffic heterogeneity in both regional and subregional MFDs. Secondly, stability of a three-state two-region system is investigated via stable equilibrium and surface boundaries analysis. Finally, a three-layer hierarchical control strategy is introduced for the studied two-region heterogeneous urban networks. The first layer of the controller calculates the stable surface boundaries for the given traffic demands and then determines the bounds of control input (split rate). An MPC approach in the second layer is used to solve an optimization problem with two objectives of minimizing total network delay and maximizing network throughput. Heterogeneity among the subregions is minimized in the last layer by implementing simultaneously a subregional perimeter flow control and an internal flow control. The effectiveness and stability of the proposed control approach are verified by comparison with four existing perimeter control strategies. 相似文献