共查询到17条相似文献,搜索用时 203 毫秒
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引 言2 0世纪 80年代末 ,余国琮、杨志才等[1] 参照连续精馏开工过程的操作方法提出并实验证明了一种新的间歇精馏操作方法———塔顶累积全回流法(本文简称“全回流”) .采用此法 ,笔者[2 ] 最近推导出在理想操作条件下间歇精馏二元理想混合物精馏过程中塔顶贮槽内液体流动为完全混合时最小汽化总量计算法 .由于采用此法 ,塔顶贮槽内存液量可能很大 ,往往必须考虑塔顶贮槽内液体流动时的混合程度 .本文以多级串联混合模型的级数表示采用此操作方法塔顶贮槽内液体流动时的混合程度 ,以在理想操作条件下间歇精馏二元理想混合物为例 ,通过举… 相似文献
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介绍了减压间歇精馏在多组分精馏生产中的优势,然后从物料组分、压力、热源、回流比的精馏操作方面进行探讨,最后对多组分减压间歇精馏操作一般过程进行总结。 相似文献
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通过构造一函数,推导出二元恒再沸比提馏式间歇精馏,在理想操作条件下,理论板数趋向无穷多时,瞬时恒浓区变化方式可由此函数值(>0或<0)来判断,完善了二元恒再沸比提馏式间歇精馏最小再沸比计算方法。推导出二元恒残液组成提馏式间歇精馏,在理想操作条件下的最小汽化总量的计算公式。通过对理论板数趋向无穷多时的能耗分析得到,二元提馏式间歇精馏,要求残液中重组分的收率和平均浓度均高时,相对于恒残液组成操作,采用恒再沸比操作能耗较高,其主要原因是低效总能耗(理论板数趋向无穷多时,直接表现为无效总能耗)在总能耗中占比例较大。 相似文献
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夹紧区是精馏塔内出现的浓度几乎不变的区域,对于三元物系来说,根据夹紧区在塔内出现的位置可分为:上、中和下加紧区.在无穷板数和任一瞬时釜浓下选择不同的回流比可使分批精馏处于不同夹紧区下操作.文中讨论了三元恒回流比分批精馏过程中夹紧区的演变,在Rayleigh方程的基础上建立了应用夹紧区原理确定多元恒回流比分批精馏最小回流比的方法.该方法并不要求相对挥发度为常数,并且能准确计算顶浓,克服了通常所采用的Underwood公式法的缺陷,为多元分批精馏的简捷设计奠定了基础. 相似文献
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常规精馏分离乙醇-异丙醇小温差体系的能耗较高,为此本文将两种机械蒸汽再压缩(MVR)热泵精馏工艺,即塔顶蒸汽直接压缩供热和塔底液相闪蒸压缩供热精馏工艺应用于乙醇-异丙醇的分离研究。利用Aspen Plus化工流程模拟软件中的严格精馏模块RadFrac.和压缩机模块Compr.,选用Wilson-RK方程计算物性数据,以分离过程的能耗最低为目标函数,对以上提出的两种MVR热泵精馏工艺分别在不同操作压力工况条件下进行了模拟与优化,得到了各自相关的工艺参数和设备参数。研究结果表明:与常规精馏工艺相比,以上两种MVR热泵精馏工艺节能分别为93.2%和93.4%。利用模拟得到的相关数据,估算了以上两种MVR热泵精馏工艺的平均年总费用,并进行了综合经济效益评价。结果表明:以上两种MVR热泵精馏工艺的平均年总费用基本持平,因此以上两种MVR热泵精馏工艺均是分离该体系较为合适的方法。 相似文献
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In this study, the effect that the top boundary has on the flow in the bottom region of a fully baffled stirred vessel of standard geometry, was investigated. Measurements of the three dimensional mean and fluctuating velocity components were made with Laser Doppler Anemometry. Calculations of the flow field were made with the commercially available CFD code FLOW3D. Three cases were studied. Two in which the top boundary was located at 30 mm, one with an air-liquid interface (open vessel) and one without (closed vessel). For the third case a closed vessel was also used and the top boundary was located at 150 mm.
The effect of removing the air-liquid interface at 300 mm on the flow in the bottom region of the vessel was small enough to be within the experimental uncertainty. Lowering the closed top boundary from 300 to 1 SO mm had a rather small impact on the flow field in the lower part of the vessel, It was concluded that the detected change is due partly to a direct effect from the introduced lid and partly to the fact that the impeller discharge is affected. The observed changes are so small that it can safely be stated that the suspension capacity of the system is not affected when the top boundary is altered within the limits of the present investigation. 相似文献
The effect of removing the air-liquid interface at 300 mm on the flow in the bottom region of the vessel was small enough to be within the experimental uncertainty. Lowering the closed top boundary from 300 to 1 SO mm had a rather small impact on the flow field in the lower part of the vessel, It was concluded that the detected change is due partly to a direct effect from the introduced lid and partly to the fact that the impeller discharge is affected. The observed changes are so small that it can safely be stated that the suspension capacity of the system is not affected when the top boundary is altered within the limits of the present investigation. 相似文献
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理想操作条件下二元提馏式间歇精馏优化操作的汽化总量与最小汽化总量的计算是约束函数优化问题。本文采用罚函数法,将此约束函数优化转变为无约束函数优化,并采用固定双步长因子梯度法数值求解该函数的极值。计算表明:固定双步长因子梯度法具有良好的收敛性,同时,降低分段数较多时,数值截断误差积累对计算结果的影响。二元提馏式间歇精馏优化操作较恒残液组成操作的能耗低的原因如下:在理论板数相对较少(接近二元提馏式间歇精馏恒残液组成操作所需的最少理论板)时,优化操作通过控制再沸比提高了能耗效率;在理论板数相对较多时,优化操作通过控制再沸比,在保证过程的能耗效率较高的同时,可尽可能快地将物料移出系统,减少了精馏过程中塔顶贮槽内液体的混合熵产。通过对计算结果的归纳与外推,得到了理想操作条件下理论板数为无穷多时二元提馏式间歇精馏优化操作再沸比的变化方式以及最小汽化总量的计算公式。 相似文献