基于Aspen Plus的聚甲氧基二甲醚精馏过程模拟分析

在装有θ环填料的精馏塔内进行了聚甲氧基二甲醚精馏实验。利用化工流程模拟软件.AspenPlus对聚甲氧基二甲醚精馏过程进行模拟,首先,采用DsTWU简捷蒸馏模型,运用软件中NRTL、WILSON、UNIQUAC,3种物性方法对精馏塔进行了计算,得到了回流比、塔板数和温度等操作参数。接着,采用RadFrac严格精馏模型对精馏塔进行了验证,其计算结果与实验结果吻合良好,满足工艺要求。最后,对精馏塔的操作变量进行了灵敏度分析,讨论了进料位置、进料流率和回流比等参数对精馏分离要求与能耗的影响,并确定了最优化方案,即:进料板为第50块,进料流率为35 mol/h,回流比为6。     

Thermodynamic evaluation of integrated gasification combined cycle: Comparison between high‐ash and low‐ash coals

In the present study, a coal‐integrated gasification combined cycle power plant is simulated. A high‐ash coal and low‐ash coal are considered to compare the performance of the plant. The combined cycle is in typical commercial size with 450 MW capacity. The feeds are Tabas and Illinois #6 coals which approximately contain more than 30% and 10% ash and have higher heating values of 22.7 MJ/kg and 26.8 MJ/kg, respectively. Energy and exergy analyses are done by aspen plus ^® and ees , respectively. Energy analysis shows that the overall efficiencies of power plants using high‐ash and low‐ash coals are 33% and 28%, respectively. The result shows that in high‐ash case, 52 kg/s coal, 10 kg/s water, and 1050 kg/s air and in low‐ash case, 48 kg/s coal and 820 kg/s air are required for providing mentioned power, approximately. Exergy analysis shows that maximum exergy destruction is in heat recovery steam generator unit. Investigating the emissions shows that high percent of ash in the coal composition has slight effects on the IGCC pollution. Finally, from thermodynamic viewpoint, it is concluded that the high‐ash coal, like the conventional one, can be used as thermally efficient and environmentally compatible feed of IGCCs. Copyright © 2016 John Wiley & Sons, Ltd.     

Comparison study on different ITM‐integrated MCFC hybrid systems with CO2 recovery using sweep gas

Previous study shows the ITM (oxygen ion transfer membrane)‐integrated MCFC (molten carbonate fuel cell) hybrid system with CO₂ recovery can maintain high efficiency; however, the oxygen partial pressure on the ITM permeate side is usually 1 atm, which requires a very high pressure ratio of the ITM air compressor in order to separate the oxygen; using the sweep gas can solve this problem. In this paper the ITM‐integrated MCFC hybrid systems with CO₂ recovery using different sweep gases are studied. With the Aspen plus software, two systems with different sweep gases are established, and their performances are compared with the benchmark system without sweep gas; the effects of key parameters on the optimum system performance are also investigated. Results show that compared with the benchmark system, the efficiencies of the systems with sweep gases are increased and the pressure ratios of the air compressors are decreased; the system using pure CO₂ as sweep gas can improve the system efficiency by 1.25%, which is superior to the system using the mixture gas of CO₂ and H₂O as sweep gas. Achievements from this paper will provide a valuable reference for CO₂ recovery from the MCFC hybrid power system with lower energy consumption. Copyright © 2016 John Wiley & Sons, Ltd.     

杨木NaOH浸渍渗透特性研究

通过自制设备对杨木NaOH浸渍渗透过程进行了实验研究。结果表明,杨木NaOH浸渍过程纵向边材渗透性能明显优于心材,而横向渗透差异较小;横向渗透为逐层渗透过程,单位渗透体积量与渗透时间呈线性关系;纵向渗透过程可分为快速渗透阶段(第一阶段)和慢速渗透阶段(第二阶段)两个阶段。在本实验条件下适当提高浸渍温度和NaOH浓度均能不同程度地改善浸渍渗透效果,而木块厚度和含水率对渗透过程均有不同程度的负面影响。     

杨木SGW浆复合纤维素酶改性的研究

对用复合纤维素酶处理杨木 Ｓ Ｇ Ｗ 浆, 改善浆的滤水性能和抄造性能进行了研究。结果表明, 用复合纤维素酶对杨木 Ｓ Ｇ Ｗ 浆进行处理, 在保持浆原强度的情况下, 浆的滤水性能有较明显的改善。     

对杨木BCTMP配抄的手抄片性能的影响研究

该文主要在实验室条件下考察了分别用高剪切纤维离解机处理前后的杨木BCTMP按不同比例与部分阔叶木浆、针叶木浆配抄手抄片物理性能的变化。结果表明,配抄后的浆张松厚度提高、粗糙度降低、不透明度提高,尤其在配抄比例为30%时,配抄BCTMP离解二段纸浆后的浆张不透明度提高率达81%;并对配抄前后总体效果进行比较,结果得出,配抄15%的BCTMP离解二段纸浆后,浆张松厚度与空白样相比提高了3.4%,表面粗糙度降低了3.8%,不透明度提高了2.9%,抗张指数增加了4.4%,耐破指数几乎不变,但撕裂指数有所下降,这表明高剪切纤维离解机处理后的杨木BCTMP有助于改善纸或纸板的质量。     

杨木CTMP碱性H2O2漂白中糖醛酸溶出的研究

研究了杨木CTMP碱性H2O2漂白过程中漂白工艺对糖醛酸溶出的影响。结果表明,糖醛酸的溶出主要受体系碱度的影响。高碱度下,H2O2的加入会在一定程度上阻碍糖醛酸的溶出;高温(如高于80℃)会加剧糖醛酸的溶出;一定温度下,糖醛酸的溶出主要在反应初期阶段较快速。正交实验结果表明,影响糖醛酸溶出的漂白工艺条件依次为NaOH用量、温度、H2O2用量、浆浓、反应时间。     

杨木化机浆成纸性能的优化

为了获得纸张松厚度与强度的平衡,通过不同游离度杨木PRC-APMP浆料进行配抄,以期更好地使用化机浆。结果显示,在填充浆(低游离度浆料)60mLCSF,骨架浆(高游离度浆料)600mLCSF,配比为0.14:1的最佳工艺下,成纸松厚度为2.437cm3·g-1,抗张指数为33.2N·m·g-1,内结合强度为272.3J·m-2。配比浆料与原浆相比,成纸的松厚度提高约6%,抗张强度和内结合强度分别提高约20%和31%。与风干干燥相比,烘干干燥不利于观察成纸松厚度的变化。     

杨木APMP制浆中的浸渍吸收性能

以杨木为原料，研究了碱性过氧化氢机械法制浆（APMP）的关键制浆工艺。采用中国制浆造纸工业研究所自制的挤碾机，重点研究了影响木片挤碾浸渍吸收性能的因素，及其对碱性过氧化氢化学预处理、成浆性能的影响。制得了白度、强度性能优良的纸浆。     

尿素在杨木APMP漂白过程中的影响

该实验探讨了在杨木碱性过氧化氢机械浆（APMP）漂白中加入尿素对纸浆ISO白度和打浆性能的影响以及在尿素存在的情况下过氧化氢（H2O2）漂白的最佳工艺。结果表明,加入尿素能提高纸浆白度,并且对纸浆的物理强度没有明显的影响,同时能降低生产成本和减轻后续处理的负担。