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夹点技术在重芳烃分离装置节能改造中的应用 总被引:1,自引:0,他引:1
使用夹点技术对某重芳烃分离装置现行的换热网络进行分析优化,以夹点温差16℃,找出该装置换热网络的夹点平均温度159.5℃,其中夹点处的热流温度为167.5℃,冷物流温度为151.5℃。计算得到装置节能潜力336.6×104kJ/h。结合该装置现行的换热网络提出了2套换热网络优化改造方案,通过2套方案的比较和可行性分析,最终确立所选方案,该方案可实现节能14.0%,节能效果显著。 相似文献
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针对某炼油厂处理量为3.5 Mt/a的柴油加氢装置,应用Aspen Plus流程模拟软件建立了装置的数学模型,计算得出了与现场标定数据比较吻合的模拟结果。根据计算结果,利用夹点技术对其换热网络进行节能分析与改造。首先以夹点温差为20℃,确定换热网络能量目标。该装置换热网络的夹点温度为95.4℃,最小热公用工程量为5 085.7 kW,最小冷公用工程量为20 613.9 kW,与现有换热网络热公用工程13 870.8 kW相比,存在8 785.1 kW的节能潜力。然后消除违背夹点规则的不合理换热匹配,进一步优化,并提出了改造方案。该方案新增7台换热器,可节约热公用工程8 450.5 kW,约降低了60.9%的能耗,取得了良好的节能效果。回收期为0.67年。 相似文献
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采用夹点技术对某MTBE裂解制异丁烯装置的现有换热网络进行了节能研究,找出了现有换热网络中存在的问题,通过对换热网络的分析和优化改造,实现了装置的节能降耗。现有换热网络热公用工程量为2154.95kW,冷公用工程量为2094.65kW,通过夹点分析确定了最小热公用工程用量为1869.83kW,最小冷公用工程用量为1809.53kW。参考央点设计原则和现有的换热网络结构,提出了优化改进方案:拆除了一台加热器和一台冷却器,新增了三台换热器。经过优化改造后,节约热公用工程量285.04kW,节能13.227%;节约冷公用工程量285.04kW,节能13.608%。 相似文献
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醋酸裂解是化工生产中的一个重要过程,其后续过程中存在着能量未充分回收利用的情况。文中利用夹点技术对醋酸裂解后续工艺的用能情况进行分析,经分析该系统为阀值问题,系统中热量过剩,故不需外加热源,所有冷物流升温所需的热量均由热工艺物流提供。但由于公用工程的引入,系统出现了2个公用工程夹点,仍需遵循夹点分析原则进行设计。针对现有的工艺流程的用能情况,利用夹点分析软件Aspen Energy Analyzer,依据夹点匹配的要求,同时考虑阀值问题的换热网络设计原则,文中提出了2种节能改造方案,并对2个方案的节能效果进行比较。经计算2个方案的节能效果均可达到40%以上,综合各方面因素考虑,方案1改造效果更好,应优先考虑。通过对醋酸裂解过程换热网络的改造,可减少冷热公用工程用量,节约成本,提高经济效益。 相似文献
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运用夹点技术分析了某化工厂中型合成氨装置的换热网络,发现现有换热网络中有较多能量利用不合理的地方。本文提出两套节能改造方案,方案一不改变现有装置的蒸汽利用系统,适当改变现有换热系统的物流匹配,充分利用现有换热网络余热,使合成氨综合能耗下降10%;方案二根据工艺过程要求优化蒸汽利用系统,进行热电联产,合成氨综合能耗降低17.9%。节能改造的投资回收期一年左右。 相似文献
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利用夹点技术对某环氧丙烷装置换热网络进行了分析,并提出优化改造方案。基于MATLAB的操作型夹点分析表明,现行换热网络夹点温差偏大(34℃)。优选夹点温差为20℃,可得最小加热和冷却公用工程量分别为1 981 kW和9 132 kW,而现行换热网络中加热和冷却公用工程量分别为3 049 kW和10 201 kW,存在较大节能潜力。进一步分析表明,现行换热网络存在违背夹点设计原则的现象,导致用能不合理。考虑换热网络变动的复杂程度和经济性,提出了一种简便的优化改造方案,可减少冷热公用工程量各300.5 kW。 相似文献
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气固流化床中信息熵的实验研究 总被引:1,自引:0,他引:1
在Shannon信息理论中的信息熵与互信息概念基础上,定义了信息传输率,用以重构相空间中研究从气固流化床内不同测量点的压力脉动时间序列之间的关联。实验结果证明了流化床内不同点之间存在着、三维的信息传输关系,提出了信息是通过床内粒子的扰动传输的,并由实验数据给出了这种压力脉动信息传输的平均速率及其随气速的变化规律。 相似文献
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引 言压力脉动信号用于气固两相流检测已经有相当长的时间 ,一般认为压力脉动信号包含了流化床内的许多动态信息 ,是颗粒特性、床的几何特性、气泡运动特性等多种因素的综合反映 .如何有效地从中提取隐含信息也一直是一个广受关注的问题 .在这方面国内外的研究者已经做过不少工作 ,包括早期研究压力脉动信号的均值、方差、功率谱、相关函数等 ,以及后来基于信号的非平稳特性的小波、Wigne -Ville谱等 ,得到了一些有用的信息 .近年来 ,随着非线性科学的发展 ,有的研究者提出流化床具有显著的混沌特性 ,Daw等在 1 990年第 1次发… 相似文献
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气固流化床信息传输和流型识别 总被引:3,自引:0,他引:3
在互信息理论和涨落复杂性理论基础上,计算了压差、压力及光纤颗粒浓度3种不同传感器测量时间序列之间信息传递的复杂性测度,建立了多传感器信息传输矩阵ITM,并定义了矩阵平均值特征参数MITM.研究了矩阵平均值MITM在不同流化状态下的变化规律,结果表明MITM对不同流型的变化有明显的指示作用. 相似文献
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A two resistance model is proposed for the heat transfer between a coaxially mounted heater and a three phase fluidized bed.
Effects of gas and liquid velocity and particle size on individual heat transfer resistances in the heater and in the fluidized
bulk zones have been determined.
The optimum bed porosity at which the maximum heat transfer coefficient occurred coincided with the bed porosity at which
the boundary layer thickness around the heater attained a minimum value. The fluidized bed resistance attained its minimum
value when the maximum heat transfer coefficient is achieved in two and three phase fluidized beds.
The heat transfer in the zone adjacent to the healer is found to be the rate controlling step since the contribution of fluidized
bed resistance was found to be less than 10% of the heater zone resistance in two and three phase fluidized beds.
The heat transfer resistances in liquid and three-phase fluidized beds have been represented by a modified Stanton and Peclet
numbers based on the heat transfer resistances in the heater zone and in the fluidized bulk zone in series. 相似文献
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在内径90mm、静床高800mm的高床层流化床中,用动态压力传感器检测了不同气速条件下普通流化床和振动流化床中沿轴向的压力脉动信号,通过小波变换对信号除噪后,用混沌理论对信号进行了分析.通过关联维数和Kolmogorov熵定量表征振动流化床中的流动结构特征.结果表明:压力脉动信号的关联维数和Kolmogorov熵能够描述振动流化床中的流化状态;振动流化床中床层的流动结构存在两个区,在近分布板区域为射流区,床层主体部分为均匀流化区. 相似文献
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Characteristics of temperature fluctuations and heat transfer coefficient have been investigated in the riser of a circulating
fluidized bed (0.102 m ID and 4.0 m in height). Effects of gas velocity and solid circulation rate on the temperature fluctuations,
suspension density and heat transfer coefficient between the immersed heater and the bed have been considered in the riser.
To analyze the characteristics of temperature fluctuations at the wall of the riser, the phase space portrait and Kolmogorov
entropy of the fluctuations have been obtained, and the relation between the temperature fluctuations and the heat transfer
coefficient has been examined. It has been found that the heat transfer system becomes more complicated and irregular with
decreasing gas velocity and increasing solid circulation rate or suspension density in the riser. The heat transfer coefficient
and Kolmogorov entropy of the temperature fluctuations have decreased with increasing the superficial gas velocity, while
they have increased with increasing the solid circulation rate or suspension density in the bed. The heat transfer coefficient
has been well correlated in terms of the Kolmogorov entropy, suspension density as well as operating variables in the riser.
This paper is dedicated to Professor Dong Sup Doh on the occasion of his retirement from Korea University. 相似文献
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The effect of chaotic temperature fluctuations on the immersed heater‐to‐bed heat transfer coefficient (h) are investigated in a liquid‐liquid‐solid fluidized bed (0.152 m ID × 2.5 m in height). The time series of temperature fluctuations are measured and analyzed by means of the multidimensional phase space portraits and Kolmogorov entropy (K), in order to characterize the chaotic behavior of heat transfer coefficient fluctuations in the bed. The overall heat transfer coefficient is inversely proportional to the Kolmogorov entropy of temperature fluctuations, as well as the fluctuation range of heat transfer coefficient (Δhi). The Kolmogorov entropy and fluctuation range of the heat transfer coefficient (Δhi) increase with increasing dispersed phase velocity, but decrease with increasing particle size. However, they attain their minima with variation of the continuous phase velocity as well as the bed porosity, at which point the flow regime of particles in the beds changes. The overall heat transfer coefficient is directly correlated with the Kolmogorov entropy, as well as the fluctuation range of heat transfer coefficient. 相似文献
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Temperature signals measured around a horizontal heat transfer tube in a bubbling fluidized bed have been analyzed using Hurst's rescaled range (R/S) analysis. This analysis estimates and identifies long-term persistence or correlation in measured time series. The Hurst exponent H, which is evaluated from R/S analysis, also provides the local fractal dimension of the time series. A new approach to analyze an air fluidized particle system is proposed based on the evaluation of the Hurst exponent. Two Hurst exponents can be evaluated from a single time series, one from the discrete time fractional noise (where the linearity of the signal is subtracted and short-term fluctuations are emphasized) and the other from the signal itself (without subtracting the linearity of the signal). The authors argue that the Hurst exponent obtained from discrete time fractional noise characterizes the particle motion, whereas the Hurst exponent obtained from the signal itself characterizes the bubble motion. Moreover, a comparison between these two Hurst components identifies the zones where an alternating type of contact between the tube surface and the bubble-emulsion phase occur. The results were interpreted in conjunction with the mutual information function. The mutual information function provides the relationship between the data points separated in time and uses only the statistical relationship between the data points. The mutual information functions and the Hurst exponents exhibited similar trends around the heat transfer tube. 相似文献