针对吸附强化乙醇水蒸气重整(SE-SRE)制氢技术,通过热力学分析和制氢实验,研究了硅酸锂加入乙醇重整的效果,并结合多种表征手段分析了掺杂K对硅酸锂的影响,进一步用实验方法探究了多种工艺条件对以掺钾硅酸锂为吸附剂的SE-SRE系统的影...针对吸附强化乙醇水蒸气重整(SE-SRE)制氢技术,通过热力学分析和制氢实验,研究了硅酸锂加入乙醇重整的效果,并结合多种表征手段分析了掺杂K对硅酸锂的影响,进一步用实验方法探究了多种工艺条件对以掺钾硅酸锂为吸附剂的SE-SRE系统的影响及该系统的循环稳定性.结果表明,硅酸锂加入乙醇重整提高了氢气产率,适量掺钾能改善硅酸锂的结晶度和孔隙特性,提升其吸附性能.SE-SRE系统的最佳工艺条件是:温度为525℃,空速为0.9 m L/(g·h),水醇体积比为8∶1,催化剂与吸附剂配比为1∶3,经过10次循环后SE-SRE系统仍能保持较高的二氧化碳吸附活性和氢气产率.展开更多
Sorption enhanced steam methane reforming（SE-SMR） was performed to maximize hydrogen production and contemporary remove COfrom the product stream using bi-functional sorbent-catalyst compounds.Samples were tested at...Sorption enhanced steam methane reforming（SE-SMR） was performed to maximize hydrogen production and contemporary remove COfrom the product stream using bi-functional sorbent-catalyst compounds.Samples were tested at two different scales: micro and laboratory. The CaO amount varied in the CaO-CaAlOsorbent system synthesized by wet mixing(CaO content of 100 wt%, 56 wt%, 30 wt%, or 0 wt% and balance of CaAlO) which were upgraded to bi-functional compounds by impregnation of 3 wt% of Ni. Nitrogen adsorption（BET/BJH）, X-Ray Diffraction（XRD）, Temperature-Programmed Reduction（TPR） and Scanning and Transmission Electronic Microscopy（SEM and TEM, respectively） analyses were performed to characterize structural and textural properties and reducibility of the bi-functional materials and evaluate their catalytic behavior. A fixed sorbent composition CaO-CaAlO(56 wt% of CaO and CaAlObalance), was chosen to study the effect of different weight hourly space times（WHST） and CHstream compositions in SE-SMR activity. Impregnated mayenite at both micro and laboratory scales showed stable Hcontent of almost 74%, with CHconversion of 72% similarly to the values reported by the sample containing 30 wt% of CaO in the post-breakthrough.Sample with 30 wt% of CaO showed promisingly behavior, enhancing Hcontent up to almost 94.5%.When the sorption enhanced reaction is performed roughly 89% of CHconversion is achieved, and after the pre-breakthrough, the catalyst worked at the thermodynamic level. During cycling sorption/regeneration experiments, even if COremoval efficiency slightly decreases, CHconversion and Hyield remain stable.展开更多
A two-dimensional transient model has been developed to describe the catalytic methane reforming （MSR） coupled with simultaneous CO2 removal by different absorbents under non-isothermal, non-isobaric and non-adiabat...A two-dimensional transient model has been developed to describe the catalytic methane reforming （MSR） coupled with simultaneous CO2 removal by different absorbents under non-isothermal, non-isobaric and non-adiabatic operating conditions. The influences of temperature, pressure and steam/carbon （S/C） on enhancement were taken into account. The results showed that the hydrogen mole fraction （dry basis） higher than 94% could be achieved using Li4SiO4, CaO, and HTC as CO2 acceptors at the operating conditions of 550~C and 0.1 MPa. When the reaction temperature varied from 500℃ to 600℃, the initial CO2 capture rates were HTC〉CaO〉Li4SiO4〉LizZrO3, and the saturation rates HTC〉CaO〉Li4SiOg〉Li2ZrO3. Increasing the reaction temperature would improve the CO2 capture rate and available CO2 capacity. For Li4SiO4, although the adsorbing rate increased as the operating temperature increased, the capacity almost did not change. At 550℃, increasing the working pressure could promote the enhancing factors of Li4SiO4,Li2ZrO3 and HTC. There was an optimal steam/carbon ratio between 2-4.5 such that all CaO, Li4SiO4, HTC and Li2ZrO3 would obtain the biggest enhancement for H2 production at the pre-breakthrough stage.展开更多
文摘针对吸附强化乙醇水蒸气重整(SE-SRE)制氢技术,通过热力学分析和制氢实验,研究了硅酸锂加入乙醇重整的效果,并结合多种表征手段分析了掺杂K对硅酸锂的影响,进一步用实验方法探究了多种工艺条件对以掺钾硅酸锂为吸附剂的SE-SRE系统的影响及该系统的循环稳定性.结果表明,硅酸锂加入乙醇重整提高了氢气产率,适量掺钾能改善硅酸锂的结晶度和孔隙特性,提升其吸附性能.SE-SRE系统的最佳工艺条件是:温度为525℃,空速为0.9 m L/(g·h),水醇体积比为8∶1,催化剂与吸附剂配比为1∶3,经过10次循环后SE-SRE系统仍能保持较高的二氧化碳吸附活性和氢气产率.
基金The financial support of European Contract 299732 UNIfHY(UNIQUE For HYdrogen production, funded by FCH-JU under the topic SP1-JTI-FCH.2011.2.3: Biomass-toHydrogen thermal conversion processes)
文摘Sorption enhanced steam methane reforming（SE-SMR） was performed to maximize hydrogen production and contemporary remove COfrom the product stream using bi-functional sorbent-catalyst compounds.Samples were tested at two different scales: micro and laboratory. The CaO amount varied in the CaO-CaAlOsorbent system synthesized by wet mixing(CaO content of 100 wt%, 56 wt%, 30 wt%, or 0 wt% and balance of CaAlO) which were upgraded to bi-functional compounds by impregnation of 3 wt% of Ni. Nitrogen adsorption（BET/BJH）, X-Ray Diffraction（XRD）, Temperature-Programmed Reduction（TPR） and Scanning and Transmission Electronic Microscopy（SEM and TEM, respectively） analyses were performed to characterize structural and textural properties and reducibility of the bi-functional materials and evaluate their catalytic behavior. A fixed sorbent composition CaO-CaAlO(56 wt% of CaO and CaAlObalance), was chosen to study the effect of different weight hourly space times（WHST） and CHstream compositions in SE-SMR activity. Impregnated mayenite at both micro and laboratory scales showed stable Hcontent of almost 74%, with CHconversion of 72% similarly to the values reported by the sample containing 30 wt% of CaO in the post-breakthrough.Sample with 30 wt% of CaO showed promisingly behavior, enhancing Hcontent up to almost 94.5%.When the sorption enhanced reaction is performed roughly 89% of CHconversion is achieved, and after the pre-breakthrough, the catalyst worked at the thermodynamic level. During cycling sorption/regeneration experiments, even if COremoval efficiency slightly decreases, CHconversion and Hyield remain stable.
基金supported by the National Natural Science Foundation of China (Grant Nos. 40972102, 50906031)the National Basic Research Program of China ("973" Project) (Grant No. 2010CB227003)
文摘A two-dimensional transient model has been developed to describe the catalytic methane reforming （MSR） coupled with simultaneous CO2 removal by different absorbents under non-isothermal, non-isobaric and non-adiabatic operating conditions. The influences of temperature, pressure and steam/carbon （S/C） on enhancement were taken into account. The results showed that the hydrogen mole fraction （dry basis） higher than 94% could be achieved using Li4SiO4, CaO, and HTC as CO2 acceptors at the operating conditions of 550~C and 0.1 MPa. When the reaction temperature varied from 500℃ to 600℃, the initial CO2 capture rates were HTC〉CaO〉Li4SiO4〉LizZrO3, and the saturation rates HTC〉CaO〉Li4SiOg〉Li2ZrO3. Increasing the reaction temperature would improve the CO2 capture rate and available CO2 capacity. For Li4SiO4, although the adsorbing rate increased as the operating temperature increased, the capacity almost did not change. At 550℃, increasing the working pressure could promote the enhancing factors of Li4SiO4,Li2ZrO3 and HTC. There was an optimal steam/carbon ratio between 2-4.5 such that all CaO, Li4SiO4, HTC and Li2ZrO3 would obtain the biggest enhancement for H2 production at the pre-breakthrough stage.
