Zr基金属氢化物的氢气纯化及回收性能研究

发布时间：2018-06-20 19:05

本文选题：氢气纯化 + 氢气回收　；参考：《北京有色金属研究总院》2015年硕士论文

【摘要】：金属氢化物具有“易于杂质气体反应”性质,可作为纯化材料用于吸附H2中的杂质气体；金属氢化物具有“可逆吸放氢”性质,可作为回收材料用于回收混合气体中H2。材料的结构及形貌分别采用XRD及SEM进行表征,金属氢化物的吸氢动力学及热力学参数选用“储氢性能测试装置”进行测试并计算,杂质气体浓度采用GC进行测定,材料的表面状态采用XPS进行分析。首先通过测试Zr基金属氢化物的吸氢PCT及动力学曲线,计算出金属氢化物的吸氢焓变、熵变及动力学激活能。随后分别对“Zr基氢气纯化材料”与两类杂质气体N2、O2及CH4、C02吸附作用规律进行了研究,包括吸附效率、吸附容量及吸附产物。测试了不同温度下材料的吸附N2及O2效率,结果表明纯化后H2(He)中N2及02浓度均低于0.500 ppm,材料吸附N2及02效率高。通过测试材料吸附N2及02穿透曲线,获得了材料的吸附N2及02容量；并发现材料纯化H2中02时,02浓度上升前,气体中先出现H20。对吸附N2及O2穿透前后,材料表面进行了XPS分析,明确材料吸附N2产物为ZrN及TiN,吸附O2产物为Zr及Ti的氧化物和氢氧化物。材料吸附CH4及CO2效率受温度影响大,温度低,吸附效率低；材料吸附CO2,会与H反应生成副产物CH4。材料吸附CH4及CO2,低温降低C原子扩散速度,使得C原子聚集在材料表面；在材料的催化作用下,表面聚集C原子与H2反应生成CH4,导致CH4浓度上升,吸附效率下降。通过测试材料吸附CH4及C02穿透曲线,获得了材料的吸附CH4及CO2容量。对吸附CO2穿透前后的材料表面进行了XPS分析,明确了材料吸附CO2产物所形成的碳化物为TiC。在“Zr基氢气纯化材料”与杂质气体吸附作用规律的研究基础之上,进行了N2及02对“Zr基氢气回收材料”吸氢过程影响的研究。测试了回收材料的吸纯氢动力学曲线,对其进行动力学模型拟合,判定材料吸氢控速步骤为“形成氢化物”过程。当H2中含有一定量N2,材料吸氢控速步骤为“化学吸附”过程,动力学曲线与Elovich经验公式相吻合。当H2中含有一定量02,材料的吸氢过程可分为快速吸氢段和缓慢吸氢段。快速吸氢段,材料表面活性高,吸氢控速步骤为“形成氢化物”过程,动力学激活能要高于材料吸纯氢。缓慢吸氢段,材料表面活性低,吸氢控速步骤为“化学吸附”过程,符合“氧化模型”。H2中同时存在N2及O2时,材料吸氢动力学符合“氧化模型’N2及O：改变回收材料的吸氢过程,对材料具有毒化效果。为提高材料的抗N2及02毒化能力,对材料进行了化学镀Pd表面改性处理。随后测试了材料经化学镀Pd后,在含N2及02混合氢气中的吸氢动力学曲线,结果表明化学镀Pd能提高材料的抗毒化能力。最后优化了化学镀Pd方法,在化学镀Pd前对材料进行了预处理。使用优化后的化学镀Pd方法对材料进行表面改性,改性后材料在含N2及O2混合氢气中的吸氢动力学性能优异,动力学符合二维扩散模型,Pd膜是一层隔绝02和N2的选择性渗氢膜。
[Abstract]:Metal hydride has the nature of "easy to react with impurity gas" and can be used as a purified material to adsorb impurity gases in H2. Metal hydrides have the properties of "reversible absorption of hydrogen". The structure and morphology of H2. materials used in the recovery of mixed gases can be characterized by XRD and SEM, and hydrogen absorption of metal hydride. The mechanical and thermodynamic parameters are tested and calculated with the "testing device for hydrogen storage performance". The concentration of impurity gas is measured by GC. The surface state of the material is analyzed by XPS. First, the hydrogen absorption enthalpy, entropy change and kinetic activation of the metal hydride are calculated by testing the hydrogen absorption PCT and the kinetic curve of the Zr based metal hydride. The adsorption of "Zr based hydrogen purification material" and two kinds of impurity gas N2, O2 and CH4, C02, respectively, including adsorption efficiency, adsorption capacity and adsorption products. The adsorption of N2 and O2 efficiency at different temperatures were tested. The results showed that the concentration of N2 and 02 in H2 (He) was lower than 0.500 ppm, and the material adsorbed N2 and 02. The absorption of N2 and the 02 penetration curve of the material is high. The adsorption of N2 and 02 capacity of the material is obtained by the adsorption of the material. It is found that before the 02 concentration of the material is purified H2, the H20. is first appeared in the gas before and after the adsorption of N2 and O2, and the surface of the material is analyzed by XPS, and the adsorption N2 products are ZrN and TiN, and the adsorption O2 product is the oxidation of Zr and the oxidation. Materials and hydroxides. The material adsorbed CH4 and CO2 efficiency greatly influenced by temperature, low temperature and low adsorption efficiency. The material adsorbed CO2, which will react with H to form a by-product CH4. material to adsorb CH4 and CO2, lower the C atom diffusion speed, and make C atoms gather on the surface of the material. Under the catalysis of the material, the surface aggregation C atom and H2 reaction generates CH4. The adsorption efficiency of CH4 increased and the adsorption efficiency decreased. The adsorption of CH4 and CO2 capacity of the material was obtained through the adsorption of CH4 and C02 through the test materials. The XPS analysis of the surface of the material before and after the adsorption of CO2 was analyzed. It was clear that the carbide formed by the adsorption of CO2 products was TiC. in the "Zr based hydrogen purification material" and the adsorption of impurities. On the basis of the study of the action law, the influence of N2 and 02 on the hydrogen absorption process of "Zr based hydrogen recovery material" was studied. The kinetic curve of the hydrogen absorption of the recycled material was tested. The kinetic model was fitted to it. The process of hydrogen absorption and control was determined as a "hydride generation" process. When a certain amount of N2 was contained in H2, the rate of hydrogen absorption and control of the material was found. In the process of "chemical adsorption", the kinetic curve coincides with the empirical formula of Elovich. When a certain amount of 02 is contained in H2, the hydrogen absorption process of the material can be divided into a fast hydrogen absorption section and a slow hydrogen absorption section. The rapid hydrogen absorption section, the high surface activity of the material, the process of hydrogen absorption and control speed is "hydrogenated" process, and the kinetic activation energy is higher than the material absorption. Hydrogen. Slow hydrogen absorption section, the material surface activity is low, the process of hydrogen absorption and control is "chemical adsorption" process. When N2 and O2 exist in the "oxidation model".H2, the hydrogen absorption kinetics of the material conforms to the "oxidation model" N2 and O: to change the hydrogen absorption process of the recycled material and to be toxic to the material. To improve the anti N2 and 02 toxicity of the material, The surface modification of electroless Pd was carried out. After electroless Pd, the kinetics curve of hydrogen absorption in N2 and 02 mixed hydrogen was tested. The results showed that the electroless plating Pd could improve the anti toxic ability of the material. Finally, the electroless plating Pd method was optimized and the material was pretreated before the Electroless plating of Pd. The optimized chemistry was used. Plating Pd method for surface modification of materials, modified materials containing N2 and O2 mixed hydrogen in hydrogen absorption kinetics performance, kinetics of a two-dimensional diffusion model of Pd membrane is a layer 02 N2 and selective isolation of hydrogen permeation membrane.
【学位授予单位】：北京有色金属研究总院
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TQ116.2;O647.3

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