一种节能效果显著的精馏节能技术——多效精馏

近些年来,随着精馏节能技术的深入发展,多效精馏引起了人们的注目。多效精馏系统由若干压力不同的精馏塔构成。而且依压力高低的顺序,相邻两个塔的高压塔塔顶蒸汽作低压塔再沸器的热源,也就是说,除压力最低的塔之外,其余各塔塔顶蒸汽的冷凝潜热均被精馏系统自身回收利用,从而使精馏过程的能耗降低。与多效蒸发类似,多效精馏的工艺流程根据加热蒸汽和物料的流向不同,通常也分为平流、顺流和逆     

多效精馏与节能

<正> 多效精馏是把普通精馏塔能够分离的均相液体混合物,改用多个压力不同的精馏塔处理,并依次用压力高的塔塔顶蒸汽作相邻压力低的塔再沸器的热源,即除压力最低的塔之外,各塔塔顶蒸汽的汽化潜热,均被精馏系统自身回收利用,从而降低精馏的能耗。作为一种精馏节能新工艺,近几年来,多效精馏的理论研究不断深入,在工业生产中的应用也日益广泛。     

多相流蒸发法高浓缩率海水淡化系统的热力学性能分析

建立了顺流进料的多相流蒸发法高浓缩率海水淡化系统的数学模型,考虑了热力损失、压力损失、盐水含量变化引起的温差损失;计算分析了相同淡水产量下固体颗粒体积分数、预热量、首效加热蒸汽温度对系统的影响。结果表明,固体颗粒体积分数和首效加热蒸汽温度对各效蒸发器传热面积影响较大;预热量对生蒸汽耗量影响较大;固体颗粒的加入能够强化传热,减小各效蒸发器的传热面积;在无预热情况下,固体颗粒体积分数为13%时,蒸发器总传热系数比固体颗粒体积分数为3%时可增大6.71%,各效蒸发器传热面积减少4.97%,淡水成本减少1.22%。     

硫酸铵多效蒸发结晶工艺的应用及设计特点

介绍了硫酸铵溶液蒸发系统采用多效蒸发结晶工艺技术的原理、流程、设备配置及设计特点。采用该工艺提高了硫酸铵溶液处理能力,减少蒸汽消耗量,使固体硫酸铵蒸汽消耗由5 t/t降为1.5t/t,解决了由于蒸汽供给不足带来的生产压力,节能效果明显。     

复杂逆流多效蒸发系统优化设计的模型与算法

建立了带有冷凝水闪蒸的复杂逆流多效蒸发系统优化设计的数学模型 ,该模型以整个蒸发系统的年总费用 (包括加热蒸汽年费用、真空泵年动力费用以及蒸发器和辅助设备的年折旧维修费用等 )最小为优化目标 ,以生蒸汽压力、冷凝器真空度及各效有效传热温度差为决策变量 ,提出一种新算法———复合形法结合Lagrangian乘子法、迭代法和矩阵法求解模型 .算例表明 ,生蒸汽压力、冷凝器真空度和冷凝水闪蒸对优化设计结果影响显著 ,优化设计比常规设计可节省年费用 11%左右 .新算法收敛稳定性好 ,收敛速度快     

三效顺流蒸发装置工艺参数的模拟分析

本文在建立三效顺流蒸发装置计算数学模型的基础上,通(?)对一烧碱溶液三效顺流蒸发装置主要工艺参数的模拟计算分析,得出了生蒸汽压力、末效二次蒸汽压力及进料温度变化时对装置生产能力影响的数量关系。其模拟计算结果对于三效顺流蒸发装置的设计计算、技术改造及确定最佳的操作参数均具有一定的参考价值.     

谈谈我厂蒸发工艺技改中的经验教训

谈谈我厂蒸发工艺技改中的经验教训由于供应的生蒸汽压力不足，将原设计三效顺流工艺改为二效顺流工艺。这样原设计中的Ⅲ效蒸发器在改后流程中相当于Ⅱ效，于是发生了效体不出料的问题。分析其原因，Ⅰ效蒸发过程中氯化钠只形成晶核，粒度小，无法分离。真正的氯化钠结晶...     

齐108块抽油机井泵效影响因素及对策研究

由于齐108块稠油油藏开采时间长,导致地层压力低、采出程度高,油井面临着井况变差以及高轮次蒸汽吞吐引起的油层出砂等问题,抽油机井泵效越来越低。     

几种密封在碱泵上的应用

一、碱泵密封问题的提出我厂烧碱蒸发工艺是采用三效三体顺流蒸发。生蒸汽的压力为7～8Kg/cm~2,第Ⅰ效蒸发器内的液面压力为3.5Kg/cm~2,碱液浓度为12～18％,温度150℃。由于液面压力高,碱液可以顺流地从第Ⅰ效过到第Ⅱ效蒸发器,因此对第Ⅰ效过第Ⅱ效的循环用泵的性能要求不高。第Ⅱ效蒸发器内的液面压力为0.5～1Kg/cm~2,碱液浓度由18％上升到22％,温度120℃。此时盐的结晶大量析出,碱液中含盐的结晶颗粒>14％,再加之蒸发器和管路等的保温厚度不够,泵体及     

三效逆流升膜蒸发装置运行总结

介绍了离子膜法烧碱三效逆流升膜蒸发工艺流程及其优点,对试车期间存在的蒸汽压力不稳定、Ⅰ效产出的碱液不合格及仪表等设备质量差的问题提出了解决措施.     

中等过冷度下含不凝性气体蒸汽冷凝传热特性

通过对竖直圆管外表面含不凝性气体蒸汽在中等壁面过冷度条件下的冷凝传热实验研究,分析了混合气体压力0.4～0.6 MPa、空气含量0.07～0.52以及壁面过冷度13～25℃时,蒸汽的冷凝换热特性,给出了冷凝传热过程中的经验关联式,并对氦气的存在及其对换热过程的影响进行了初步分析。结果表明：在混合气体压力及不凝性气体含量不变的条件下,壁面过冷度的降低利于冷凝传热系数的增长;所得到的经验关联式在低过冷度条件下能较好地对换热过程进行预测,且其与实验值的误差在±15%以内;实验条件下未发生氦气分层现象,相同不凝性气体质量分数条件下,氦气的存在会使冷凝传热系数降低约20%。     

Steam flow law in horizontal wells when considering reservoir heterogeneity

Steam injection in horizontal wells for thermal recovery of heavy oil is a complex and changeable process. The prediction of thermal properties of steam along horizontal wells is critical to the uniform production of reservoirs. In this paper, considering the mutual coupling effects of reservoir permeability, confining pressure, and steam phase transition, a comprehensive mathematical model for predicting steam injection flow in horizontal wells was established. Compared with the on-site logging data, the accuracy of the model was verified. The simulation results show that under a single variable condition, the larger the steam injection pressure at the heel, the faster the mass flow and steam dryness decrease. When the steam injection pressure drops from 11 MPa to 8.5 MPa, the steam distribution distance doubles. At the same position, the higher the steam dryness at the heel, the greater the mass flow in the steam injection well, and the faster the steam pressure decrease. Double the steam injection dryness, the pressure drop is almost doubled, but the longer steam injection distance. The larger the steam injection flow at the heel, the faster the steam pressure decreases, and the decrease in the steam dryness in the tube slows down. When the steam injection flow increases by 1.75 times, the pressure drop increases by 5.3 times. The higher the reservoir permeability, the faster the steam dryness decreases. By obtaining the general rules of steam distribution in horizontal wells to provide theoretical support for on-site steam injection, the steam distribution effect can be effectively improved to increase production and reduce consumption.     

考虑储层非均质时注汽井内蒸汽流动规律

稠油热采水平井注蒸汽是一个复杂多变的过程，水平井沿程蒸汽热物性的预测对于储层的均匀动用十分关键。考虑储层渗透率、围压和蒸汽相变等条件的相互耦合影响，建立了预测水平井注汽流动的综合数学模型。与现场测井数据进行对比分析，验证了模型的准确度。模拟结果表明，单一变量条件下，水平井跟部注汽压力越大，注汽井内质量流量和蒸汽干度下降越快，当注汽压力由11 MPa降为8.5 MPa时，配汽距离增加1倍；在水平井相同位置处，跟部注汽干度越高，注汽井内质量流量越大，且蒸汽压力下降越快，注汽干度提高1倍时，压降也几乎增加1倍；跟部注汽流量越大，蒸汽压力下降越快，注汽流量提高1.75倍时压降提高了5.3倍，但管内蒸汽干度下降趋缓；储层渗透率越高，注汽井内的蒸汽干度下降越快。该模型可以为现场注汽提供理论支撑，有效提高配汽效果达到增产降耗。     

蒸汽喷射压缩器的变工况特性分析

蒸汽喷射压缩器工作特性对系统性能产生很大的影响。文中采用气体动力函数法,建立了蒸汽喷射压缩器变工况特性数值计算模型,对热压缩海水淡化系统中的蒸汽喷射压缩器的变工况性能进行了计算,分析了工作蒸汽压力、引射压力、混合蒸汽压力对喷射系数的影响。计算结果表明,当压缩蒸汽的压力低于一定值时,喷射系数保持不变;喷射压缩器特性对蒸发压力的变化最为敏感,引射压力的微小变化将导致喷射器性能的明显变化;而提高工作蒸汽压力,在一定范围内可以提高喷射器的性能,但超过一定数值后反而会引起喷射器性能的降低。与试验结果对比表明,采用该方法能够正确地预测喷射压缩器的工作性能。     

直管式直流蒸汽发生器不同运行参数下两相流压降预测

将B&W公司的直流蒸汽发生器进行简化,采用常热流边界条件进行不同运行参数下直流蒸汽发生器二次侧流动与换热过程数值模拟,并与经典摩擦压降经验关联式进行对比。结果表明：Martinelli-Nelson关联式更适用于预测蒸干发生时两相流的摩擦压降;摩擦压降随质量含汽率增加整体呈现上升趋势,蒸干发生时摩擦压降的变化率明显增大;管内气液两相流摩擦压降随质量流量和热通量增加而增大,随运行压力增大而减小。其中质量流量、运行压力对摩擦压降的影响较明显,热通量对其影响较小。     

高压蒸汽法处理锂云母提锂工艺研究

高压蒸汽中的水可快速溶解强碱,局部产生高浓度强碱环境,在此条件下,强碱能较快地与锂云母反应,达到高效碱溶的效果。通过对蒸汽压力、锂云母与强碱的质量比、反应时间、锂云母孔径对锂云母中锂的转化率的影响研究,确立了高压蒸汽法处理锂云母提锂工艺优化条件：蒸汽压力为9 MPa、锂云母与强碱的质量比为1∶1.2、反应时间为2 h、锂云母粒度为150 μm,在该条件下,锂云母中锂的转化率可以达到96.9%。     

Low energy steam explosion treatment of plant biomass

The rational operational condition for maximizing the pretreatment effect on plant biomass while minimizing heat required was investigated. Eucalyptus globulus chips were used to evaluate the operational method for the most efficient conversion of plant biomass into useful materials by steam explosion. The energy consumption required to carry out the steam explosion was calculated by considering the mass balances of the water, the wood component, and the heat balance in the steam explosion apparatus. The energy consumption increased significantly with the increase of steam pressure and steaming time, and decreased rapidly with increase of the thickness of the heat‐insulating material in the steam explosion apparatus. The amount of methanol‐soluble lignin, a low molecular weight lignin, was measured experimentally under various operational conditions such as steam pressure and steaming time. The steam explosion at the steam pressure of 3.9 MPa and steaming time of 1.1 min was the most effective method for maximizing the delignification with low energy consumption. © 2001 Society of Chemical Industry     

蒸汽喷射压缩器的变工况特性模拟与分析

采用改进热力学,建立了蒸汽喷射压缩器变工况特性数值计算模型。结合水蒸气物性程序,对热压缩海水淡化系统中的蒸汽喷射压缩器的变工况性能进行了计算,分析了工作蒸汽压力、引射压力、混合蒸汽压力的变化对引射系数的影响。计算结果表明,当压缩蒸汽的压力高于设计值时,引射系数随压缩压力的增大而减小,而当压缩低于设计值时,引射系数保持不变;提高引射蒸汽压力会引起引射系数的增大;主动蒸汽压力偏离设计值时,主动蒸汽压力的降低（低于设计值）或提高均会引起喷射器性能的降低。     

Experimental study on performance of steam-water injector with central water nozzle arrangement

The steam-water injector (SI) is a simple mechanical device that has been widely used in industry. We did an experimental study to find the influence of physical and geometrical parameters on performance of the SI. The physical parameters studied were steam inlet pressure, water inlet pressure and water inlet temperature. Whereas, the geometrical parameters studied were steam nozzle area ratio, area ratio of steam nozzle to water nozzle and the mixing section converging angle. Pump head was introduced to evaluate the lifting-pressure performance of the SI under different operating and geometrical conditions. Optimal values of steam nozzle area ratio and mixing section converging angle were 1.3 and 11.6° respectively, for the present work, and optimal value of area ratio of steam nozzle to water nozzle increased with increasing water inlet pressure. Two head-capacity curves were introduced to highlight the effect of various physical and geometrical parameters on the performance of SI.     

Significant Effect of Pressure on the H2 Releasing from Photothermal-Catalytic Water Steam Splitting over TiSi2 and Pt/TiO2

This study reports the significant pressure effect on the photocatalytic activity of hydrogen generation over two kinds of representative semiconductor catalysts (TiSi₂ and Pt/TiO₂). The photothermal-catalytic hydrogen generation from water steam splitting under visible light was achieved. And the physicochemical properties of the photocatalysts were characterized by XRD and XPS techniques. Compared to the conventional liquid-solid-phase photocatalytic method, this gas-solid-phase photothermal-catalytic method for hydrogen releasing from water steam exhibited a higher apparent quantum yield (22.01%) under the high pressure.