褐煤超大型直管式气流干燥装置工业生产的设计

根据褐煤高水分、易燃易爆的特点,介绍了褐煤超大型直管式气流干燥装置工业生产的设计思路,针对调试运行过程中出现的问题提出了切实可行的解决方案。     

Indirect land use change for biofuels: Testing predictions and improving analytical methodologies

Current practices for estimating indirect land use change (iLUC) due to United States biofuel production rely on assumption-heavy, global economic modeling approaches. Prior iLUC studies have failed to compare their predictions to past global historical data. An empirical approach is used to detect evidence for iLUC that might be catalyzed by United States biofuel production through a “bottom-up”, data-driven, statistical approach. Results show that biofuel production in the United States from 2002 to 2007 is not significantly correlated with changes in croplands for corn (coarse grain) plus soybean in regions of the world which are corn (coarse grain) and soybean trading partners of the United States. The results may be interpreted in at least two different ways: 1) biofuel production in the United States through 2007 (the last date for which information is available) probably has not induced any indirect land use change, and 2) this empirical approach may not be sensitive enough to detect indirect land use change from the historical data. It seems clear that additional effort may be required to develop methodologies to observe indirect land use change from the historical data. Such efforts might reduce uncertainties in indirect land use change estimates or perhaps form the basis for better policies or standards for biofuels.     

Simultaneous heat exchanger network synthesis for direct and indirect heat transfer inside and between processes

Process plants are typically divided into different process parts having specific processing tasks with possibly different ownership. Heat integration between these processes can increase the energy- and economic efficiency for both the overall plant and the individual processes. In this paper we present a heat exchanger network synthesis MINLP-model that allows simultaneous heat integration directly between streams in the same process and both directly and indirectly between streams in different processes. The indirect heat transfer is accomplished by using intermediate streams. Two examples, one small explanatory one and one from the literature, are optimized. The results verify that the model works logically.     

Leveling the playing field of transportation fuels: Accounting for indirect emissions of natural gas

Natural gas transportation fuels are credited in prior studies with greenhouse gas emissions savings relative to petroleum-based fuels and relative to the total emissions of biofuels. These analyses, however, overlook a source of potentially large indirect emissions from natural gas transportation fuels, namely the emissions from incremental coal-fired generation caused by price-induced substitutions away from natural-gas-fired electricity generation. Because coal-fired generation emits substantially more greenhouse gases and criteria air pollutants than natural-gas-fired generation, this indirect coal-use change effect diminishes potential emissions savings from natural gas transportation fuels. Estimates from a parameterized multi-market model suggest the indirect coal-use change effect rivals in magnitude the indirect land-use change effect of biofuels and renders natural gas fuels as carbon intensive as petroleum fuels.     

陡河发电厂#7机组氢湿度超标的原因及对策

氢冷发电机内氢气湿度超标,多数情况下不会对发电机立即产生明显的破坏,但随着运行时间的延长,必将对发电机内部部件产生不良影响,甚至威胁发电机的安全运行。陡河发电厂#7机组运行中氢气湿度经常出现超标的现象。本文从超标的原因及预防上做了简要的分析,其中重点介绍了氢干燥器运行中调整的注意事项。     

240万t/a球团厂铁精矿干燥系统的设计

对240万t/a球团生产线的铁精矿干燥系统进行了分析及计算,结果认为,采用4×20 m圆筒干燥机比3.6×24 m圆筒干燥机更适合。由热平衡计算得出,干燥系统配备的风机风量为13.5万m3/h,为节省电耗,风机应采用变频调速。对干燥废气安装补热装置有助于控制废气温度高于露点温度,从而确保布袋除尘器的安全运行。     

ON A NEW DRYER FOR SLAG OR FLY-ASH

Granulated blastfurnace slag or fly-ash, asadmixture of slag cement or pozzolana cement, has to be driedbefore it is ground with clinker, for it contains water. Here, anew dryer for drying slag or fly-ash is recommended,which iscalled suspension dryer.     

关于谷物干燥热耗折算系数的研究报告

谷物干燥热耗折算系数,是标定谷物干燥机性能的重要参数。本文以大型横流,混流干燥机的试验数据为基础,依据国内外有关谷物干燥的理论,对谷物干燥热耗折算系数进行了探索性研究。研制出可用于横流、混流干燥机在不同大气条件,不同谷物条件的热耗折算系数。该“折算系数”的提出,为建立各种干燥机技术性能之间的可比性提供了依据。     

造纸机干燥部的研究与发展

介绍了造纸机干燥部的研究与发展历程以及目前正在使用的几种纸页干燥方式，同时介绍了国内外最新的干燥技术，分析了纸页干燥技术未来的发展方向和研究的课题。     

A robust sliding mode flux and speed observer for speed sensorless control of an indirect field oriented induction motor drives

In this paper a new sliding mode flux and speed observer is proposed for indirect field oriented induction motor drive system. The error between the actual and observed currents converges to zero, which guarantees the accuracy of the flux observer. The rotor speed and the rotor time constant are estimated based on the estimated stator currents and rotor flux. The estimated rotor time constant is used in slip calculation and observer structures and the estimated speed is used as feedback to the speed regulation. Computer simulation and experimental results of the speed control verify the validity of the proposed speed estimation algorithm. The experimental results show the robustness and performance of the proposed observer structure. Experimental results have been realized without load, with load and with external disturbances.