大型空气分离系统建模与低能耗化研究
发布时间：2019-05-27 05:49
【摘要】：空分系统是典型的高耗能系统,由于近年来其规模不断增大,导致其总能耗、关键部机设计难度与各子系统复杂程度与日俱增,大型空分系统理论层面存在的障碍亟待深入研究与强化。面向12万Nm3/h产氧量等级外压缩空分系统与其关键子系统展开建模与低能耗化研究,力图阐明并解决空分系统在大型化过程中存在的部分问题,并促进大型空分系统的低能耗化。在分析了12万Nm3/h等级外压缩空分流程主要参数的基础上,对常规外压缩空分系统进行了(?)分析,发现空分系统的(?)损在六大子系统中的分布呈现出非常不均匀的特点。压缩冷却系统、精馏系统、吸附纯化系统和主换热器系统是空分系统最主要的(?)损来源,是研究的重点方向。而膨胀制冷系统和液空液氮过冷系统(?)损很小,挖潜增效空间有限。基于此,研究了一种空压机废热用于纯化器解吸过程污氮气加热的方案,强化关键部机间的能量耦合。研究表明,该方案使纯化器电加热器的年耗电量降低1209.4万度电,空气压缩与冷却系统的(?)效率从54.3%提升到55.8%,空分系统的总(?)损降低了5.64%,一定程度上提高了空分系统的能量效率和(?)效率。研究了一种应对大流量场合的多通道并联径流式纯化器,建立了该纯化器的吸附模型,并采用实验数据验证了吸附模型。研究表明,双通道与三通道径流式纯化器比单通道结构的体积分别减小了27.8%和31.7%,压降分别减小了10.8%和56.4%,降低了空压机排压要求,有助于降低空分系统的能耗。此外双通道结构的击穿时间增大了23.1%,使得吸附剂的吸附容量得到更充分的利用。基于积累热负荷最小化提出了一种多股流板翅式换热器通道排列的方案,采用分布参数传热模型获取了板翅式换热器的换热效果,并与前人的方案进行对比。研究表明,多股流板翅式换热器的积累热负荷的均方差较前人方案减小了2.9%。通过基于分布参数传热模型的优化方案使空气、污氮气、氮气通道出口温度不均匀度分别下降7.8%,4.1%和82.0%,换热器的热负荷均匀度与换热效率得到提高,促进了空分系统的低能耗化。此外,为了降低建模的复杂性,将Modelica建模引入空分精馏过程,并与常规的BP算法建模方式展开对比,分析了二者获取的氧、氮浓度分布的准确性。通过对大型空分系统开展建模与低能耗化研究,优化了空气压缩与冷却系统、分子筛纯化系统、多股流板翅式换热系统等关键子系统的性能,促进了空分系统效率的提高和能耗的降低,取得的结果对今后大型空分系统的研究具有较好的参考价值。
[Abstract]:Air separation system is a typical high energy consumption system. Due to the increasing scale of air separation system in recent years, the total energy consumption of air separation system is increasing, and the design difficulty of key parts and the complexity of each subsystem are increasing day by day. The obstacles existing in the theoretical level of large air separation system need to be deeply studied and strengthened. For 120000 Nm3/h oxygen production grade external compression air separation system and its key subsystems, modeling and low energy consumption research are carried out, and some problems existing in the process of large-scale air separation system are expounded and solved. And promote the low energy consumption of large air separation systems. Based on the analysis of the main parameters of 120000 Nm3/h grade external compression space separation process, the conventional external compression space separation system is carried out. It is found that the (?) The distribution of losses in the six subsystems is very uneven. Compression cooling system, distillation system, adsorption purification system and main heat exchanger system are the most important (?) The source of loss is the key direction of research. The expansion refrigeration system and the liquid-air liquid-nitrogen supercooling system (?) The damage is very small, and the space for tapping potential and increasing efficiency is limited. Based on this, a scheme of waste heat of air compressor for nitrogen heating in the desorption process of purifier is studied, which strengthens the energy coupling between the key components. The results show that the annual power consumption of the purifier heater is reduced by 12.094 million degrees, and the air compression and cooling system is reduced by the air compression and cooling system. The efficiency increased from 54.3% to 55.8%, and the total of the air separation system was increased from 54.3% to 55.8%. The loss is reduced by 5.64%, which improves the energy efficiency and (?) Efficiency. A multi-channel parallel runoff purifier for large flow situation is studied, and the adsorption model of the purifier is established, and the adsorption model is verified by experimental data. The results show that the volume of dual-channel and three-channel radial purifier is reduced by 27.8% and 31.7%, the pressure drop is reduced by 10.8% and 56.4%, respectively, and the exhaust pressure requirement of air compressor is reduced. It helps to reduce the energy consumption of air separation system. In addition, the breakdown time of the two-channel structure increases by 23.1%, which makes the adsorption capacity of the adsorbents more fully utilized. Based on the minimum accumulated heat load, a scheme of channel arrangement of multi-flow plate-wing heat exchanger is proposed. The heat transfer effect of plate-wing heat exchanger is obtained by using the distributed parameter heat transfer model, and compared with the previous schemes. The results show that the mean square error of accumulated heat load of multi-flow plate-finned heat exchanger is 2.9% lower than that of previous schemes. Through the optimization scheme based on the distributed parameter heat transfer model, the temperature inhomogeneity of air, polluted nitrogen and nitrogen channels is reduced by 7.8%, 4.1% and 82.0%, respectively, and the heat load uniformity and heat transfer efficiency of the heat exchanger are improved. It promotes the low energy consumption of air separation system. In addition, in order to reduce the complexity of modeling, Modelica modeling is introduced into the process of air separation distillation, and compared with the conventional BP algorithm modeling method, the accuracy of oxygen and nitrogen concentration distribution obtained by the two methods is analyzed. Through the research of modeling and low energy consumption of large air separation system, the performance of key subsystems such as air compression and cooling system, molecular sieves purification system and multi-stream plate-wing heat transfer system is optimized. The efficiency of air separation system is improved and the energy consumption is reduced. The results obtained have good reference value for the research of large air separation system in the future.
【学位授予单位】：华中科技大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：TQ116.1
[Abstract]:Air separation system is a typical high energy consumption system. Due to the increasing scale of air separation system in recent years, the total energy consumption of air separation system is increasing, and the design difficulty of key parts and the complexity of each subsystem are increasing day by day. The obstacles existing in the theoretical level of large air separation system need to be deeply studied and strengthened. For 120000 Nm3/h oxygen production grade external compression air separation system and its key subsystems, modeling and low energy consumption research are carried out, and some problems existing in the process of large-scale air separation system are expounded and solved. And promote the low energy consumption of large air separation systems. Based on the analysis of the main parameters of 120000 Nm3/h grade external compression space separation process, the conventional external compression space separation system is carried out. It is found that the (?) The distribution of losses in the six subsystems is very uneven. Compression cooling system, distillation system, adsorption purification system and main heat exchanger system are the most important (?) The source of loss is the key direction of research. The expansion refrigeration system and the liquid-air liquid-nitrogen supercooling system (?) The damage is very small, and the space for tapping potential and increasing efficiency is limited. Based on this, a scheme of waste heat of air compressor for nitrogen heating in the desorption process of purifier is studied, which strengthens the energy coupling between the key components. The results show that the annual power consumption of the purifier heater is reduced by 12.094 million degrees, and the air compression and cooling system is reduced by the air compression and cooling system. The efficiency increased from 54.3% to 55.8%, and the total of the air separation system was increased from 54.3% to 55.8%. The loss is reduced by 5.64%, which improves the energy efficiency and (?) Efficiency. A multi-channel parallel runoff purifier for large flow situation is studied, and the adsorption model of the purifier is established, and the adsorption model is verified by experimental data. The results show that the volume of dual-channel and three-channel radial purifier is reduced by 27.8% and 31.7%, the pressure drop is reduced by 10.8% and 56.4%, respectively, and the exhaust pressure requirement of air compressor is reduced. It helps to reduce the energy consumption of air separation system. In addition, the breakdown time of the two-channel structure increases by 23.1%, which makes the adsorption capacity of the adsorbents more fully utilized. Based on the minimum accumulated heat load, a scheme of channel arrangement of multi-flow plate-wing heat exchanger is proposed. The heat transfer effect of plate-wing heat exchanger is obtained by using the distributed parameter heat transfer model, and compared with the previous schemes. The results show that the mean square error of accumulated heat load of multi-flow plate-finned heat exchanger is 2.9% lower than that of previous schemes. Through the optimization scheme based on the distributed parameter heat transfer model, the temperature inhomogeneity of air, polluted nitrogen and nitrogen channels is reduced by 7.8%, 4.1% and 82.0%, respectively, and the heat load uniformity and heat transfer efficiency of the heat exchanger are improved. It promotes the low energy consumption of air separation system. In addition, in order to reduce the complexity of modeling, Modelica modeling is introduced into the process of air separation distillation, and compared with the conventional BP algorithm modeling method, the accuracy of oxygen and nitrogen concentration distribution obtained by the two methods is analyzed. Through the research of modeling and low energy consumption of large air separation system, the performance of key subsystems such as air compression and cooling system, molecular sieves purification system and multi-stream plate-wing heat transfer system is optimized. The efficiency of air separation system is improved and the energy consumption is reduced. The results obtained have good reference value for the research of large air separation system in the future.
【学位授予单位】：华中科技大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：TQ116.1
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