共查询到18条相似文献,搜索用时 46 毫秒
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碘硫循环是目前提出的效率最高、最有希望实现工业应用的热化学分解水制氢流程。碘硫循环由Bunsen反应、氢碘酸分解反应和硫酸分解反应组成。其中,硫酸分解是碘硫循环及其他含硫热化学循环中的共同步骤,需要在高温及催化剂存在下进行。本文以铁酸铜作为硫酸分解的催化剂,考察了反应温度、硫酸进料速率以及催化剂用量等因素对硫酸分解转化效率的影响,并与Pt催化剂的效果进行了比较。在铁酸铜催化的条件下,转化率比没有催化剂时平均提高了22%。温度超过820 ℃,催化效果与负载质量分数1%的Pt/Al2O3相当;催化剂活性在9 h内未出现下降趋势。用X射线衍射、比表面积全分析吸附、透射电镜以及热重-差热等方法对使用前后的铁酸铜进行了表征,给出了物相参数、表面性能参数及热稳定性等数据。 相似文献
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热化学循环被认为是以清洁和可持续的方式实现大规模制氢的有前途的制氢方案,对其工艺和经济性进行分析,从技术的成熟度和投资的成本等方面给出不同循环的优势和劣势具有重要的意义。从反应堆的适应性、技术的成熟度和生产规模等方面分析了不同热化学循环之间的差异,并讨论了这些方法的优缺点和面临的挑战。此外,还根据循环的热效率、制氢的成本和全球变暖潜能值(GWP),对不同的热化学循环进行了对比分析。研究结果表明,硫-碘热化学循环(SI)在热效率、成本和GWP方面都具有一定的优势,但是由于运行温度相对较高,能与之耦合的反应堆受限;硫酸混合循环(HyS)的GWP最低,但是在高温条件下面临硫酸的分解问题;铜-氯热化学混合循环(Cu-Cl),由于其运行温度较低,在反应堆耦合、低品位热量利用、制氢成本和环境影响方面都显示出巨大的潜力。 相似文献
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硫碘制氢是目前最有潜力的大规模低成本制氢方法之一。HI催化分解是硫碘制氢的关键步骤。本文采用4种具有代表性的镍盐前体--硝酸镍[Ni(NO3)2]、乙酸镍[Ni(CH3COO)2]和两种有机金属络合镍(乙酰丙酮镍[Ni(acac)2]和亚硝酸三乙二胺合镍([Ni(en3)](NO2)2)制备Ni催化剂,考察了不同镍盐前体对制备的Ni催化剂特性的影响规律以及Ni催化剂在HI催化分解中的性能。采用了BET、XRD和TEM等分析测试技术对制备的Ni催化剂进行了表征。研究结果表明,镍盐前体对制备的Ni催化剂的分散度、催化活性以及催化稳定性有重要的影响。以Ni(NO3)2和[Ni(en3)](NO2)2为前体制备的Ni催化剂具有良好的Ni金属分散度,Ni颗粒分散均匀且尺寸较小。由于高温和强腐蚀的反应环境(HI-I2-H2O体系),Ni催化剂经过反应都会出现不同程度的失活。以[Ni(en3)](NO2)2为前体制备的Ni催化剂表现出最好的催化活性和稳定性,有望成为未来大规模硫碘制氢系统中HI分解的催化剂。 相似文献
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综述了碘硫循环制氢中用于HI浓缩分离的3种主要技术路线,即磷酸萃取精馏、反应精馏以及电解电渗析预浓缩-精馏的研究进展,对各路线的过程原理、操作流程、能量利用效率等方面进行了讨论,在此基础上对比了其各自的优点和不足之处,并对其应用前景进行了展望。其中,磷酸萃取精馏开发最早,相对成熟,但操作流程复杂,运行效率需进一步提升;反应精馏流程有望以高集成度取得高效率,但所需条件非常苛刻,其设备开发、工艺实验等工作亟待展开;近年来发展较快的电解电渗析预浓缩-精馏工艺由于具有操作简单,条件温和,浓缩效率高等优点而具有较好的应用前景,其进一步工艺放大、模块化以及与精馏的高效协同等都是未来研究的重点和难点。 相似文献
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Iodine-sulfur(IS) thermochemical water-splitting cycle is the most promising massive hydrogen production process.To avoid the undesirable side reactions between hydriodic acid(HI) and sulfuric acid(H2SO4),it is necessary to purify the two phases formed by the Bunsen reaction.The purification process could be achieved by reverse reaction of the Bunsen reaction.In this study,the purification of the H2SO4 and HI Phases was studied.The purification proceeded in both batches and the continuous mode,the influences of operational parameters,including the reaction temperature,the flow rate of nitrogen gas,and the composition of the raw material solutions,on the purification effect,were investigated.Results showed that the purification of the H2SO4 phase was dominantly affected by the reaction temperature,and iodine ion in the sulfuric acid phase could be removed completely when the temperature was above 130℃;although,the purification effect of the HI phase improved with increasing of both the flow rate of nitrogen gas and temperature. 相似文献
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The cycle characteristics of thermochemical resorption refrigeration system were investigated, and the experimental comparison between the basic resorption cycle and adsorption cycle was performed. Experimental results showed that the conversion rate during the regeneration phase in the resorption refrigeration cycle was higher than that in the adsorption refrigeration cycle at the same constraining temperatures. However, the conversion rate was lower during the cold production phase in the former cycle than in the latter cycle. Moreover, the reaction plateau temperature in the resorption cycle was lower than that in the adsorption cycle at the same regeneration temperature and heat sink temperature. The thermal capacity of metallic part of reactor has a stronger influence on the system performance for the resorption cycle compared with the adsorption cycle. At a regeneration temperature of 180 °C, heat sink temperature of 25 °C and refrigeration temperature of 10 °C, theoretical results showed the COP of a simple test unit operating on the resorption cycle to be 0.40. The resorption refrigeration technology is more suitable for cold production in some special situations where the presence of liquid is not desirable. 相似文献
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Vivek Utgikar Bradley Ward 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》2006,81(11):1753-1759
The nuclear energy driven thermochemical cycle is one of the potential water‐splitting processes for producing hydrogen, presumed to be the transportation fuel of the future. A life cycle assessment (LCA) of one such system, which utilizes nuclear energy to drive the ISPRA Mark 9 thermochemical cycle, is presented in this paper. The results of the LCA are presented in terms of the emissions of greenhouse gases (CO2‐equivalent) and acid gases (SO2‐equivalent). The contributions of the thermochemical plant to the emissions were determined through the estimation of material and energy requirements for chemical inventory, raw materials consumption and plant fabrication/installation. The greenhouse gas emissions from the system are 2515 g CO2‐equivalent kg?1 H2 produced and acid gas emissions 11.252 g SO2‐equivalent kg?1 H2 produced. A comparison of this hydrogen production route with other routes, including steam reforming of methane and high‐temperature electrolysis, is also presented in the paper. Copyright © 2006 Society of Chemical Industry 相似文献
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Ho-Sang Choi Seong-Dae Hong Gab-Jin Hwang Chu-Sik Park Ki-Kwang Bae Kaoru Onuki 《Korean Journal of Chemical Engineering》2006,23(2):288-291
Pervaporation (PV) of water from HIx solution (HI-H2O-I2 mixture) using Nafion-117 was evaluated aiming at the application to dehydrate the azeotropic composition in HI decomposition
reaction of thermochemical IS process. PV experiment was carried out by using HI solutions of 40–65 wt% and an I2/HI molar ratio of 0–3 in the feed at the room temperature. The permeation flux decreased with increasing HI weight fraction
in the feed. The permeation flux is dependent on the I2 concentration in the feed having an I2/HI molar ratio. A long time PV experiment was carried out using I2/HI molar ratio of 1 (in HI solution of 55.9%) in the feed at room temperature. It is expected that the permeation component
in the permeate zone using the PV process was mainly H2O, and H2O permeation was constant with increasing operation time. 相似文献
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对一种基于固-气可逆化学反应的热化学复合吸附储热循环的储热特性以及能量品位提升性能进行了理论分析,并以MnCl2/SrCl2/NH3作为工质对进行了实验研究。理论分析表明,热化学复合吸附储热循环不仅可以降低外界驱动热源的温度并保证输出热能温度稳定,而且能大幅度地提升输出热能的温度品位。在MnCl2和SrCl2都参与放热的实验工况下,获得的储热效率为93.31%。MnCl2复合吸附剂的总储热密度按单位质量反应盐MnCl2和单位质量的固化吸附剂计量分别为4393.36和3734.36 kJ·kg-1;SrCl2复合吸附剂的总储热密度按单位质量反应盐SrCl2和单位质量的固化吸附剂计量分别为1947.28和1655.19 kJ·kg-1。结果表明,热化学储热是一种相当有潜力的储热方式,可为低品位热能的高效回收利用提供强有力的技术支持。 相似文献