Determination of a suitable index for a solvent via two-column extractive distillation using a heuristic method

The traditional approach to solvent selection in the extractive distillation process strictly focuses on the change in the relative volatility of light-heavy components induced by the solvent. However, the total annual cost of the process may not be minimal when the solvent induces the largest change in relative volatility. This work presents a heuristic method for selecting the optimal solvent to minimize the total annual cost. The functional relationship between the relative volatility and the total annual cost is established, where the main factors, such as the relative volatility of the light-heavy components and the relative volatility of the heavy-component solvent, are taken into account. Binary azeotropic mixtures of methanol-toluene and methanol-acetone are separated to verify the feasibility of the model. The results show that using the solvent with the minimal two-column extractive distillation index, the process achieves a minimal total annual cost. The method is conducive for sustainable advancements in chemistry and engineering because a suitable solvent can be selected without simulation verification.     

基于低影响开发理念的雨水控制设计计算

文中介绍了某电影文化综合体项目采用的集中雨水控制利用技术:透水性地面铺装、屋顶绿化、下凹式绿地、微生态雨水处理回用一体机。通过合理划分汇水面积,结合项目实际情况,计算给出了在限定年径流总量控制率的条件下,合理采用多种手段联合,使项目符合《绿色建筑评价标准》(GB/T 50378—2014)中的场地生态设计要求,实现了海绵城市的控制目标,也为类似工程提供了参考思路。     

变压精馏分离甲苯-乙醇体系的经济最优化设计

甲苯-乙醇体系的共沸组成与相对挥发度对压力比较敏感,可用变压精馏分离该体系。利用Aspen化工流程模拟软件,以年度总费用最小为目标函数,以NRTL为热力学计算模型,采用序贯迭代法确定普通、部分热集成和完全热集成的变压精馏最优工艺参数。结果表明完全热集成更具有优势。     

集中式空调系统能耗评价体系的研究

结合武汉地区的工程，给出了典型建筑当量满负荷运行时间，讨论了集中空调系统全年能耗计算方法和能耗评价体系，认为周边全年热负荷系数PAL、空调能耗因数CECAC是适合评价我国集中空调系统设计是否合理的有效能耗评价指标，但CECAC对基于计算负荷偏大所匹配的空调设备没有约束边界条件，建议尽快研究适合我国的PAL，CECAC基准。     

An exergy application for analysis of buildings and HVAC systems

The paper presents an extended method for exergy analysis of buildings and Heating Ventilation Air Conditioning (HVAC) systems, according to an energy demand build-up model from the building side to the energy supply side. The HVAC systems comprise a thermal energy emission and control system, a thermal distribution system, an electricity distribution system and an energy conversion system. Energy and exergy that are required by a building and a HVAC system are posed into the external part and classified by different forms of energy carriers. The external part is out of the boundary of the study. The method is illustrated with an office building equipped with low-temperature heating and high-temperature cooling systems situated in the Netherlands. Thermal exergy and thermal energy demands of the building and thermal energy and thermal exergy losses occurring in the HVAC systems are discussed. The building and the HVAC systems to be considered meet standard Dutch energy performance regulations. Nevertheless their overall exergy efficiencies are low in both cases (17.15% and 6.81% subsequently). The exergy analysis also pinpoints that the thermal energy emission and control system and the energy conversion system are the main causes of the exergy inefficiencies in the heating and cooling cases, respectively.     

几种能源供暖方式的技术经济比较

分析了几种能源供暖方式的初投资和经营费用，给出了费用年值的计算公式。采用费用年值法对几种能源供暖方式的经济性和使用过程的技术性进行了比较。     

规划中居民的用气高峰小时计算流量

在城市规划方案里，市政燃气配套规划中的用气量计算是制定燃气管网输配计划和燃气系统发展规划的基础。文章说明了精确的用气量计算对于燃气系统经济性、安全性及可靠性具有特别重要的意义；阐述了居民用户经验年用气量和居民用户实际开户率对居民高峰小时计算流量的影响；探讨了居民高峰小时计算流量的计算方法。