SIMULATION STUDIES OF THE REMOVAL OF WATER FROM ETHANOL BY A CATALYTIC DISTILLATION PROCESS

A new approach based on catalytic distillation (CD) technology was proposed to remove water from ethanol. Isobutylene was introduced to react with water in the CD column. The commercial software simulation tool Aspen Plus was used to investigate the effects of key design factors such as operating pressure and temperature, reactant ratios, reflux and distillate to feed ratios, number of separation and reaction stages, and feed and reaction zone location. It was found that the CD technology offers potential advantages of reduced energy consumption and reduced capital cost over traditional approaches for the removal of water from ethanol.     

隔壁精馏塔分离芳烃混合物的模拟研究

采用隔壁精馏塔分离苯-甲苯-对二甲苯物系,用Aspen Plus软件模拟了隔壁精馏塔内温度分布及液相组成分布,考察了汽相和液相分配比对产品纯度的影响。对隔壁精馏塔模拟得到的优化操作条件为:隔壁精馏塔的理论板数为30块,侧线采出在第14块理论板,进料段为15块理论板,在进料段的第7块理论板进料,进料组成n(苯)∶n(甲苯)∶n(对二甲苯)为1∶3∶1,回流比为8.8,液相分配比为2.96,汽相分配比为0.83。在此条件下,各组分的摩尔分数大于98.5%,与实验结果基本吻合。当进料组成n(苯)∶n(甲苯)∶n(对二甲苯)为1∶3∶1时,采用隔壁精馏塔可比常规两塔流程节能27.18%。     

肟交换法制备乙醛肟工艺的研究

肟交换法是一种制备乙醛肟的新兴工艺,但反应过程存在乙醛肟易被空气氧化等问题,且反应液中存在多组共沸物,分离提纯得到高纯度的乙醛肟较为困难。以丁酮肟为原料,通过向反应器内充入0.2 MPa的氮气,有效避免了乙醛肟氧化与原料乙醛、丁酮肟的挥发,乙醛肟反应选择性达96.12%。开发了产物的提纯工艺,通过Aspen Plus模拟,初步确定减压精馏分离反应液的基本流程,考察了压力、塔板数、回流比、进料位置等操作参数对分离过程的影响。在此基础上,依据模拟确定的操作参数进行实验,确定最优分离提纯工艺,得到纯度为95.33%的乙醛肟产品,收率可达94.31%。本研究可为肟交换法制备乙醛肟的工业化提供一定的指导。     

基于CaO引导的甲烷蒸汽重整化学链燃烧制氢系统

为在重整气中得到高纯H_2和降低尾气CO_2分离成本,建立了基于CaO引导的甲烷蒸汽重整化学链燃烧制氢系统,该系统在重整反应器中加入CaO吸收剂,用以吸收重整器内的CO_2,提高重整气中H_2浓度,形成的CaCO_3固体在煅烧器中受热分解重新生成CaO。利用Aspen Plus进行了过程模拟及热力学分析,并研究主要参数对系统性能的影响,得到优化的操作条件为:CaO循环量/CH_4比为0.5,CH_4(燃料)/CH_4比为0.35,NiO循环量/CH_4比为1.4。CaO循环量/CH_4比从0变化到0.5时,重整气中H_2浓度从0.60增长到0.99;CH_4(燃料)/CH_4比在0.25~0.45区间变化时,重整气中H_2浓度从0.86提高到0.99,产气量增加;NiO循环量/CH_4比在1~1.6区间变化时,重整气中H_2浓度从0.88增长到0.99,系统有效能效率变化较小。     

用ASPEN PLUS软件预测水-2,3-丁二醇汽液相平衡数据

讲述了用Aspen Plus软件估算汽液相平衡数据的一般方法，并给出了水-2，3-丁二醇和2，3-丁二醇-1，3-丙二醇物系在不同压力下的汽液相平衡数据，结果表明通过精馏操作可以将2，3-丁二醇分离提纯。     

沼气微型燃气轮机热力循环特性的仿真模拟

针对沼气设备的研发,基于Aspen PLUS分别建立了回热式和外燃式热力循环模型,研究了增压比π、涡轮前温度T3、压气机进口空气温度和涡轮出口压力对系统特性的影响,100kW级沼气燃气轮机的增压比选取值为其总体设计提供了参考。通过对比2种热力循环的特性发现,外燃式热力循环更易于回热器的匹配设计,同等涡轮前温度和低增压比的条件下,外燃式整机热效率略优于回热式。     

LNG冷能用于冷库制冷性能模拟研究

为使LNG冷能在冷库系统中得到有效利用,从LNG冷能梯级利用的角度出发,设计一种新型LNG冷能制冷的冷库系统,在LNG换热器端和冷库末端实现对LNG冷能的梯级利用,并通过HYSYS模拟对其进行热力学分析和经济性分析.结果表明:该冷库系统COP为1.82,火用效率为80.2%;LNG换热器火用损最大,约占系统总火用损的78.9%,且随LNG进口温度升高而减小;系统COP和火用效率均随LNG进口温度及气化压力升高而增大;该系统投资回收期为4.77 a,具有较好的经济效益.LNG冷能为冷库系统冷量来源提供新的选择,在LNG进口端增设蓄冷设备和加压泵均能提高系统COP和火用效率.     

基于响应面法的三甘醇脱水参数优化北大核心CSCD

目的解决三甘醇工艺脱水效率降低及能耗偏高等问题,对操作参数进行优化。方法采用灵敏度分析法和响应曲面法对运行参数进行优化。①采用灵敏度分析法选出富液进塔温度、重沸器温度、TEG贫液循环量、汽提气体积流量作为因素变量,以干气水露点和运行费用为响应值,通过HYSYS软件模拟计算25组试验数据;②采用响应曲面法进行分析和优化。结果富液进塔温度和汽提气体积流量间的交互作用对干气水露点影响最显著,富液进塔温度和TEG贫液循环量间的交互作用对运行费用影响最显著,优化后的最佳工艺参数为:富液进塔温度144.28℃、重沸器温度205.4℃、TEG贫液循环量4 m^(3)/h、汽提气体积流量24.96 m^(3)/h。在干气水露点满足外输要求和天然气处理量为300×10^(4) m^(3)/d的情况下,运行费用可降低69.33万元/年。结论响应面法可为指导现场运行参数优化提供理论基础。     

Remote sensing of photosynthetic light-use efficiency across two forested biomes: Spatial scaling

Eddy covariance (EC) measurements have greatly advanced our knowledge of carbon exchange in terrestrial ecosystems. However, appropriate techniques are required to upscale these spatially discrete findings globally. Satellite remote sensing provides unique opportunities in this respect, but remote sensing of the photosynthetic light-use efficiency (ε), one of the key components of Gross Primary Production, is challenging. Some progress has been made in recent years using the photochemical reflectance index, a narrow waveband index centered at 531 and 570 nm. The high sensitivity of this index to various extraneous effects such as canopy structure, and the view observer geometry has so far prevented its use at landscape and global scales. One critical aspect of upscaling PRI is the development of generic algorithms to account for structural differences in vegetation. Building on previous work, this study compares the differences in the PRI: ? relationship between a coastal Douglas-fir forest located on Vancouver Island, British Columbia, and a mature Aspen stand located in central Saskatchewan, Canada. Using continuous, tower-based observations acquired from an automated multi-angular spectro-radiometer (AMSPEC II) installed at each site, we demonstrate that PRI can be used to measure ? throughout the vegetation season at the DF-49 stand (r² = 0.91, p < 0.00) as well as the deciduous site (r² = 0.88, p < 0.00). It is further shown that this PRI signal can be also observed from space at both sites using daily observations from the Moderate Resolution Imaging Spectro-radiometer (MODIS) and a multi-angular implementation of atmospheric correction (MAIAC) (r² = 0.54 DF-49; r² = 0.63 SOA; p < 0.00). By implementing a simple hillshade model derived from airborne light detection and ranging (LiDAR) to approximate canopy shadow fractions (α_s), it is further demonstrated that the differences observed in the relationship between PRI and ε at DF-49 and SOA can be attributed largely to differences in α_s. The findings of this study suggest that algorithms used to separate physiological from extraneous effects in PRI reflectance may be more broadly applicable and portable across these two climatically and structurally different biome types, when the differences in canopy structure are known.     

基于Virtools的三维交互虚拟精馏实验室的构建

为了实现对精馏分离实验过程的三维情景化交互仿真模拟,提出了一种基于Virtools技术的、以虚拟人物为引导的,全场景、开放式、三维沉浸交互式虚拟精馏实验室的构建方法。该软件以板式塔实验为考察对象,依据精馏分离理论建立了分离预测数学模型并以此为构建基础,通过对功能模块、实现的关键技术以及三维沉浸感提升方法的研究与设计,采用编写及优化程序实现了物系选择、多参数调节、监控评价和色谱检测等功能,计算了不同条件下沿塔气液组成和温度分布,完整地模拟了精馏分离和馏出液检测全过程。