Thermodynamic and isotopic studies in eruptive gases

The Erta' Ale volcano has provided a series of high quality volcanic gas samples. Thermodynamic calculations show that homogeneous equilibrium is established within the gaseous phase, the oxidation state of which is consistent with the oxygen fugacity in equilibrium with the basalt (10^−9.33atmat 1130°C). Moreover, carbon and sulphur stable isotope analyses permit to define gases of true magmatic origin and conversely, to get information on the isotopic state of mantle volatile elements.     

Thermodynamic and transport properties of gases for use in solid oxide fuel cell modelling

Data are provided and estimation methods presented for the calculation of specific heat capacities, viscosities, thermal conductivities and diffusion coefficients for both pure components and mixtures of C₃H₈, C₂H₆, CH₄, H₂O, CO₂, CO, H₂, N₂, O₂ and Ar over the temperature range 273–1473 K at ambient pressure. Pure component data is assembled from various data compilations supplemented by validated estimation techniques. Fourteen estimation methods for mixture properties have been compared with each other and with over 1400 experimental data points to facilitate the choice of methods best suited to this application. A statistical analysis of the data (including expected accuracy) is presented and recommendations are made for practical use.     

Thermodynamic analysis of in-situ hydrogen from hot compressed water for heavy oil upgrading

Due to many benefits of heavy oil upgrading in the green medium of hot compressed water (HCW), the present study considers the thermodynamic analysis of in-situ hydrogen created by partial oxidation of light hydrocarbons (HC) in HCW. The aim is seeking the upgrading condition where light hydrocarbons create hydrogen (H₂) and carbon monoxide (CO) assisted by partial oxidation of light hydrocarbons. The formed CO collaborates in in-situ active hydrogen through water gas shift reaction (CO+H₂O↔H₂+CO₂) which is more effective than external hydrogen for hydrogenation of heavy oil in HCW. Applying the powerful capability of Aspen Plus®, i.e., sensitivity analysis, the effect of significant parameters, such as temperature, pressure (water density), water to oil ratio, and oxygen (O₂) to oil ratio are studied comprehensively in order to maximize the amount of active hydrogen. The results indicate that higher temperatures and the amount of water (H₂O/heavy oil) are two favorable factors to increase the contribution of active hydrogen, while the pressure is not a determinant factor at supercritical condition (P ≥ 25 MPa). The formation of methane is also decreased at high temperature which is desired for upgrading system. The higher amount of water implies more quantity of O₂ since partial oxidation affords the enthalpy of auto-thermal reforming of HO. Hence there should be a compromise in the selected ratios of H₂O/HC and O₂/HC in HCW upgrading system. A set of experiments are conducted in order to compare the simulation and experimental results. Although the experimental results are established on kinetic data which also reflect the physical effect of HCW during HO upgrading, however, the thermodynamic study provides valued information, in agreement with experiments, that improves our understanding of HO upgrading in HCW with less coke.     

Thermodynamic assessments of a novel integrated process for producing liquid helium and hydrogen simultaneously

Liquid helium and hydrogen are two precious cryogens with advanced applications in various energy research fields. However, producing these cryogens generally come with high-cost processes. In this research, Liquid hydrogen is obtained in two stages with the aid of a mixed refrigeration subprocess and helium cryogen. Also, liquid helium is obtained in three stages with the aid of helium upgrader, pressure swing adsorption, and helium liquefier subprocesses. The liquid helium is produced at 19.42 K, 195 kPa, and 6161 kgmole/h. Also, the liquid hydrogen is produced at 3.69 K, 110.3 kPa, and 17,970 kgmole/h. The novelties of this research can be described as the production of liquid helium and hydrogen simultaneously, low SEC, novel configuration, and production of liquid helium and hydrogen at near ambient pressure. Thermodynamic analyses show that the specific energy consumption, coefficient of performance, and figure of merit are equal to 18.96 kW h/kg, 0.03, and 0.37, respectively. Also, the exergy analysis shows that the exergy efficiency and exergy destruction in the whole process are equal to 67% and 4471 MW, respectively. Also, sensitivity analysis shows that increasing the PSA process efficiency positively impacts all process parameters like SEC, COP, FOM, and exergy efficiency.     

Thermodynamic assessment of IGCC power plants with hot fuel gas desulfurization

In IGCC power plants, hot gas desulfurization (HGD) represents an attractive solution to simplify syngas treatments and to improve the efficiency, potentially reducing the final cost of electricity. In the present study, the various consequences of the introduction of a HGD station in the power plant are discussed and evaluated, in comparison with conventional near-ambient temperature clean-up. Attention is paid to the potential improvements of the overall energy balance of the complete power station, along with the requirements of the sorbent regeneration process, to the influence of the desulfurization temperature and to the different solutions needed to control the NO_x emissions (altered by the presence of HGD).     

高温岩体圈定的思路与方法探讨

高温岩体地热资源开发利用首先要解决的是在目前技术和经济条件下可以开发利用的高温岩体分布地区和赋存深度及规模。提出了高温岩体圈定的基本思路应该是在对高温异常区的岩石类型及分布、断裂构造格架及其活动性、火山活动和岩浆侵入的类型及时代等基础地质研究的基础上,并充分利用地球物理探测技术、遥感技术、地球化学方法,配合少量深钻验证工程来进行。特别强调了在高温岩体地热资源圈定和评价中多种方法和技术的相互配合、相互补充、相互验证。     

Review of principles and methods of severe plastic deformation for producing ultrafine-grained tubes

Severe plastic deformation (SPD) is known to be the best method for producing bulk ultrafine-grained and nanostructured materials with excellent properties. Different SPD methods were developed that are suitable for sheet and bulk solid materials. During the past decade, efforts have been made to create effective SPD processes suitable for producing cylindrical tubes. In this paper, we review SPD processes intended to produce ultrafine-grained and nanostructured tubes, and their effects on material properties. The paper will focus on introduction of the tube SPD processes, and then comparison of them based on their advantages and disadvantages from the viewpoints of processing and properties.     

中水源热泵用于生活热水系统方案设计

结合工程实例,详细介绍了利用水源热泵进行学校浴室废水热能回收的方案设计,并对该系统和传统燃气锅炉系统的年运行费用进行比较。结果表明该系统具有很好的节能潜力。     

Thermodynamic analysis of a Stirling engine including dead volumes of hot space, cold space and regenerator

This paper provides a theoretical investigation on the thermodynamic analysis of a Stirling engine. An isothermal model is developed for an imperfect regeneration Stirling engine with dead volumes of hot space, cold space and regenerator that the regenerator effective temperature is an arithmetic mean of the heater and cooler temperature. Numerical simulation is performed and the effects of the regenerator effectiveness and dead volumes are studied. Results from this study indicate that the engine net work is affected by only the dead volumes while the heat input and engine efficiency are affected by both the regenerator effectiveness and dead volumes. The engine net work decreases with increasing dead volume. The heat input increases with increasing dead volume and decreasing regenerator effectiveness. The engine efficiency decreases with increasing dead volume and decreasing regenerator effectiveness.     

Evaluation of alternative methods of preparing hydrogen producing seeds from digested wastewater sludge

Six digested sludges, pre-treated by different methods (heat-shock, aeration, acid and base treatments, 2-bromoethanesulfonic acid (BESA) inhibition and iodopropane inhibition) as well as an untreated sample were compared for their suitability in the preparation of hydrogen producing seeds by cultivations in a sucrose medium. The heat-shock and acid treatment methods completely repressed methanogenic activity; however, they also partially repressed hydrogen production. The base treatment option did not completely repress methanogenic activity and also significantly impacted hydrogen production. The aeration method was unsuccessful at completely repressing methanogenic activity; however, it did not significantly affect the hydrogen production activity. The BESA and iodopropane pre-treatment methods specifically inhibited the methanogens, and there were no significant effects found on hydrogen production. Similar to the aeration pre-treated digested sludge sample, the untreated sludge showed high hydrogen production activity and a small amount of methanogenic activity (lower than the activity detected in the base treatment sample). In the subsequent second-step batch cultivations with the same sucrose medium and the diluted media, methanogenic activity was not detected in any of the test bottles. The microbial seed prepared from base treatment exhibited the highest hydrogen production activity, whereas those prepared from acid treatment did not exhibit any activity. Again, the microbial seed prepared from untreated sludge also exhibited relatively high hydrogen producing activity. A lower pH was detected at the end of the cultivation in all the test bottles. Interestingly, the variations in pH in the different tests bottles indicate that pH is an important parameter in the control of methanogenic activity.     

火炬气回收技术

介绍了三种火炬气回收工艺。提出了火炬气回收的优化方案。回收火炬气不仅可以创造显著的经济效益,而且可减少环境污染。     

Azeotropic pressure swing distillation of hydrochloric-water for hydrogen production in the CuCl cycle: Thermodynamic and design methods

A pressure swing distillation (PSD) process is designed and analyzed in this paper for the maximum boiling azeotrope separation of an HCl-water binary mixture to recycle concentrated HCl (aq) within the CuCl cycle of thermochemical hydrogen production. Aspen Plus simulation and EES software are used to evaluate the characteristics of the PSD apparatus in terms of flow streams, thermodynamic properties and compositions in the binary azeotropic mixture. A heat transfer and mass transfer analysis (with the McCabe-Thiele method) are also used to predict the height of the packed bed distillation column. Results indicate that both analyses predict the same values for the low and high pressure packing column height of 1.7 m and 2 m, respectively. Due to the component's volatility changes through the azeotropic transition at the HCl-water separation, the minimum and maximum concentration of the HCl (aq) would be at the distillate ports of low and high pressure columns, respectively. Moreover, to break the azeotropic point of HCl (aq) in the PSD system, the minimum required low pressure feed concentration at the operating line slopes of 0.2, 0.4, 0.6 and 0.8 should be 0.086, 0.092, 0.097 and 0.103, respectively. From the results, the re-boiler and condenser heat duties at the high pressure distillation column are more affected with the change in the slope of the operating line, compared to the low pressure side.     

太阳能热水系统用热管性能要求及功率测试方法

阐述了热管传热性能的重要参数——等温性和传输功率的测试方法。规定了热管测试中,蒸发段、绝热段和冷凝段的长度、循环水流量以及进出口的温度差等参数的要求及控制方法。提出了一般的热管质量控制方案。     

多功能太阳能空调制热兼制热水模式负荷平衡控制策略的研究

为了解决多功能太阳能空调制热兼制热水工况时空调和热水的能量输入与各自的负荷平衡问题,提出了通过调节热水换热器水体积流量以改变空调传热量和热水传热量的控制策略.以空调负荷作为控制目标,建立了神经网络辨识和模糊控制模型,并进行了仿真研究.结果表明,神经网络预测和模糊控制相结合的方法对热水换热器水体积流量的智能调节能有效地解决负荷平衡问题.