共查询到19条相似文献,搜索用时 64 毫秒
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聚丙烯环管反应器的模拟 总被引:6,自引:0,他引:6
以荆门石化总厂 7万t/a聚丙烯装置为基础 ,介绍了环管反应器特点 ,分析了物料在环管反应器中的流动特性 ,建立了符合其性能的数学模型。通过对模型的求解 ,得到了固含率、单体浓度、反应器温度、冷却水温度、聚合反应速率、链转移反应速率和催化剂失活速率等参数与环管反应器管长度的关系 ,为聚丙烯环管反应器的优化操作提供了理论依据 相似文献
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聚丙烯环管反应器的动力学特征 总被引:9,自引:0,他引:9
讨论了聚丙烯环管反应器内聚丙烯反应机理,反应速率;以齐鲁石化公司塑料厂的实际运行数据为基础,建立了物热衡算数学模型;并通过对模型求解,得到了反应器内的聚合速率,固含率在不同产量下随温度的变化规律,通过分析得出其温度的最佳操作域。 相似文献
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近年来,聚丙烯工业有了飞速的发展,聚丙烯产品逐渐成为世界合成树脂中发展最快,品种开发最活跃、应用范围最广的品种之一。丙烯聚合属于非均相阴离子配位反应,其反应机理非常复杂,加之聚丙烯生产工艺多种多样,如何建立聚合反应过程的数学模型,并实现聚合过程的计算机仿真是进行聚丙烯生产过程优化和控制的基础。本文就是主要针对聚丙烯环管反应器建立相应的数学模型。 相似文献
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根据聚丙烯环管反应器的特点,总结了生产中可能出现的危险因素,即超温、超压、循环中断等紧急状况,据此设计了反应器的紧急停车动作,同时介绍了TRICON系统的特点,以及如何在TRICON系统中实现紧急停车动作,包括硬件组态和软件组态两个方面 相似文献
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外环流反应器中气含率的研究 总被引:5,自引:1,他引:4
本文研究了外环流反应器中气含率的轴向分布,不同环路阻力下气含率与气速、液速之间的关系,以及降液管中的气泡夹带。用流动模型对三种结构下的气含率数据进行了关联,得到了有意义的结果。 相似文献
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环流反应器中液相循环速度的测定 总被引:2,自引:2,他引:0
通过对环流反应器中液相循环速度的测定研究,开发了一种双探针探头联机检测技术,并相应建立了一套测定环流反应器液相循环速度的在线检测系统。 相似文献
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This investigation was intended to aid in the selection of impeller design and operating conditions, which would exhibit minimum turbulence in an internal loop reactor for axial flow velocities up to 18 cm/s.
For this purpose we measured power consumption, liquid flow velocity and mixing time with two marine propellers (pitch ratio tan alpha =1 and 0.57, respectively) and with flat-blade fan-type impellers (blade angles 10 to 90°).
The present results showed that at flow velocities between 7 and 14 cm/s a reduction in the pitch ratio (tan alpha) of the marine propeller from 1 to 0.57 increased the mechanical flow efficiency.
In addition, the fan-type impeller with a blade angle of 20° displayed flow characteristics comparable to the marine propellers; therefore, owing to its simple design, the fan-type impeller offers a practical substitute for the marine propellers.
In cell culture, draft-tubes used in impeller-driven reactors (internal loop reactors) offer two important features:
1. They simplify the design and scale-up process over that of open-blade impellers (flow patterns are more uniform);
2. They provide a mechanical support for bubblte-free membrane oxygenators;
Furthermore, on the assumption that loop reactors display lower bulk turbulence than open blade impellers for similar power consumption, this investigation was intended to aid in the selection of impeller design and operating conditions which would exhibit maximum pumping efficiency (with minimum mixing).
For this purpose, using a pH tracer method, we determined mechanical flow efficiency and dimensionless mixing time, which served as parameters for pumping efficiency to establish the following specific design characteristics:
1. Bulk mixing decreases relative to bulk flow with increasing bulk flow (mixing therefore conforms to the flow-in-pipe model) for two marine propellers (pitch tan alpha = 1 and 0.57) and for fan-type impellers (variable pitch) up to a blade angle of 30°;
2. Liquid velocity increases directly proportional to impeller speed up to 17 cm/s for (above) propellers, as well as fan-type impellers with blade angles of less than 30°;
3. The mechanical efficiency of axial flow (liquid velocity/power input) increases by decreasing the impeller pitch of marine impellers from tan alpha = 1 to tan alpha = 0.57, in the range of 7-14 cm/s;
4. A fan-type impeller (variable pitch) with a pitch angle of 20° displayed flow velocity and mechanical efficiency values, which lay between those of the (above) two marine propellers.
Fan-type impellers are considerably simpler in construction and are simpler to modify than marine propellers; for this reason this impeller type serves as a useful investigational tool. In addition we have found that at an impeller of 20° this type of impeller may be used to substitute marine propellers with a pitch ratio between 1 and 0.57.
We also suggest that square pitch marine propellers are not the most suitable for reactors in which mechanical efficiency of axial flow is critical, such as those for “shear sensitive” animal and plant cells. 相似文献
For this purpose we measured power consumption, liquid flow velocity and mixing time with two marine propellers (pitch ratio tan alpha =1 and 0.57, respectively) and with flat-blade fan-type impellers (blade angles 10 to 90°).
The present results showed that at flow velocities between 7 and 14 cm/s a reduction in the pitch ratio (tan alpha) of the marine propeller from 1 to 0.57 increased the mechanical flow efficiency.
In addition, the fan-type impeller with a blade angle of 20° displayed flow characteristics comparable to the marine propellers; therefore, owing to its simple design, the fan-type impeller offers a practical substitute for the marine propellers.
In cell culture, draft-tubes used in impeller-driven reactors (internal loop reactors) offer two important features:
1. They simplify the design and scale-up process over that of open-blade impellers (flow patterns are more uniform);
2. They provide a mechanical support for bubblte-free membrane oxygenators;
Furthermore, on the assumption that loop reactors display lower bulk turbulence than open blade impellers for similar power consumption, this investigation was intended to aid in the selection of impeller design and operating conditions which would exhibit maximum pumping efficiency (with minimum mixing).
For this purpose, using a pH tracer method, we determined mechanical flow efficiency and dimensionless mixing time, which served as parameters for pumping efficiency to establish the following specific design characteristics:
1. Bulk mixing decreases relative to bulk flow with increasing bulk flow (mixing therefore conforms to the flow-in-pipe model) for two marine propellers (pitch tan alpha = 1 and 0.57) and for fan-type impellers (variable pitch) up to a blade angle of 30°;
2. Liquid velocity increases directly proportional to impeller speed up to 17 cm/s for (above) propellers, as well as fan-type impellers with blade angles of less than 30°;
3. The mechanical efficiency of axial flow (liquid velocity/power input) increases by decreasing the impeller pitch of marine impellers from tan alpha = 1 to tan alpha = 0.57, in the range of 7-14 cm/s;
4. A fan-type impeller (variable pitch) with a pitch angle of 20° displayed flow velocity and mechanical efficiency values, which lay between those of the (above) two marine propellers.
Fan-type impellers are considerably simpler in construction and are simpler to modify than marine propellers; for this reason this impeller type serves as a useful investigational tool. In addition we have found that at an impeller of 20° this type of impeller may be used to substitute marine propellers with a pitch ratio between 1 and 0.57.
We also suggest that square pitch marine propellers are not the most suitable for reactors in which mechanical efficiency of axial flow is critical, such as those for “shear sensitive” animal and plant cells. 相似文献
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根据肌苷发酵过程主要是溶氧传质控制的结论,本文研究了操作变量和装置结构变量对环流发酵反应器中氧传递的影响,定量地得到气含率,液体循环速度和结构因素对氧传递的关系。对发酵反应器中溶氧浓度分布进行了摸拟计算,依据计算的结果提出了较佳的 D_E/D 和 L_E/D 的结构。 相似文献
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液固环管反应器中液固两相轴向扩散特性的研究梁五更,俞芷青,金涌,汪展文,陈靖(清华大学化学工程系,北京100084)关键词:环管反应器,液固系统,轴向扩散1前言混合特征是反应器的基本流体力学性质。有关环管反应器的混合行为已有一些研究,但都集中于气-液... 相似文献
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LOCAL LIQUID SIDE MASS TRANSFER MODEL IN AIRLIFT LOOP REACTOR AND SELF-ASPIRATED REVERSED FLOW JET LOOP REACTOR 总被引:1,自引:0,他引:1
Combining Higbie's penetration theory and Kolmogoroff's theory of isotropic turbulence, a small-scale isotropic mass transfer model for the local liquid side mass transfer coefficients in a gas-liquid two-phase airlift loop reactor and a self-aspirated reversed flow jet loop reactor has been developed. Good agreement with the experimental data suggests a general applicability of the proposed model in these reactors. 相似文献
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针对矩形卧式多级串联环流反应器,在改变结构和气速的情况下,对全系统的气含率、上流区和下流区的气含率、液相循环速度、液相返混等进行了实验考察,并利用漂流模型,最小能耗原理等进行了模拟计算。 相似文献
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气提式外环流反应器的液相流动模型 总被引:1,自引:0,他引:1
在接近中试规模的气提式外环流冷模反应装置上,就气-液两相及气-液-固三相两种情形,运用脉冲示踪-响应技术,以电导法测定反应器不同轴向位置示踪粒子年龄分布。随后,建立合理的数学模型,给出具体的定解条件,并进行参数估值,找出Pe与uL、Qg之间的内在规律。进而获得结论:改变试验条件,Pe准数在27.0-46.0变化。 相似文献