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排序方式: 共有348条查询结果,搜索用时 31 毫秒
1.
《International Journal of Hydrogen Energy》2005,30(11):1259-1264
Based on the water gas shift (WGS) catalytic mechanism on precious metal catalyst, a Langmuir–Hinshelwood (LH) kinetics model was derived for the operating conditions of syngas from natural gas reforming at near-ambient pressure. A power law kinetics model was also presented for comparative purpose. These two kinetics models were integrated in a dynamic distributed reactor model for design of full-scale WGS reactors for a natural gas fuel processing system. Modeling results indicated that the LH kinetics model gives predictions of reactor performance closer to the experimental data. Using the LH kinetics model, optimization of operating conditions for the high-temperature shift (HTS) and low-temperature shift (LTS) reactors was also attempted. 相似文献
2.
Shishan Xue Guanfei Liu Jingjuan Lai Peng An Yang Liu Yuanpeng Wu Yu Wang Zhiyong Ye Qiao Tang Hongwei Zhou 《大分子材料与工程》2021,306(11):2100415
Self-healing hydrogels often possess poor mechanical properties which largely limits their applications in many fields. In this work, boron nitride nanosheets are introduced into a network of the poly(vinyl alcohol)/borax (PVA/borax) hydrogels to enhance the mechanical properties of the hydrogel without compromising the self-healing abilities. The obtained hydrogels exhibit excellent mechanical properties with a tensile strength of 0.410 ± 0.007 MPa, an elongation at break of 1712%, a Young's Modulus of 0.860 ± 0.023 MPa, and a toughness of 3.860 ± 0.075 MJ m−3. In addition, the self-healing efficiency of the hydrogels is higher than 90% within 10 min at room temperature. Benefiting from the excellent self-healing properties, the shapeability of the hydrogel fragments is observed using different molds. In addition, the hydrogels display rapid pH-driven shape memory effects and can recover to their original shape within 260 s. Overall, this work provides a new approach to hydrogels with integrated excellent mechanical properties, self-healing abilities, and rapid pH-driven shape memory effects. 相似文献
3.
无破胶剂聚合物压裂液的研究 总被引:1,自引:0,他引:1
在合成了由短链分子聚合和交联的新型无破胶剂压裂液的基础上,考察了增稠剂浓度、交联剂用量对压裂液性能的影响,评价了新型无破胶剂压裂液的综合性能。结果表明,当增稠剂浓度在2.0%以上,交联剂浓度增加,液体的粘度迅速增大;无破胶剂压裂液在170 s-1的剪切速率下120 min后仍具有较好的剪切稀释性;新型无破胶剂压裂液与常规的胍胶相比,同样具有滤失量低的特点,在90℃下,压裂液仍有较好的携砂能力;其还具有表面活性剂清洁压裂液无残渣、易返排的特点。此外,该压裂使用方便,还可再生重复使用。 相似文献
4.
The effects of chloride ion, temperature, pH value, CO2 and O2 on the corrosion induced leakage of the inner wall of crude oil pipeline with the produced water were investigated by electrochemical polarization. The results showed that chloride ion corrosion would gradually experience the smooth invariant stage, the slow rise stage, and the rapid rise stage which due to the chloride ion destroy the corrosion product film. The corrosion rate would reach a maximum when the temperature was 65 °C or the pH value was 3.5. O2 was the dominant factor induced the increase of corrosion rate when compared with the effect of CO2. Moreover, long term and periodic (30 consecutive days) electrochemical CO2 corrosion tests suggested that the CO2 corrosion rate reached a maximum at 4 days. The obtained results would facilitate the formulation of control measures for pipeline corrosion in the oil field. 相似文献
5.
《Carbon》2014
Uniform nitrogen and sulfur co-doped carbon nanospheres with an average diameter of approximately 200 nm were prepared using sulfur and polyacrylonitrile as precursors. The materials were characterized using scanning electron microscopy, transmission electron microscopy, elemental analysis, and X-ray photoelectron spectroscopy. The characterization results suggest the as-prepared materials had uniform, porous, nanospherical morphologies and high surface areas. For the typical sample containing 9.5% sulfur, the surface area is up to 653 m2 g−1. The catalysts exhibited enhanced catalytic activity, outstanding long-term stability, and excellent methanol tolerance in an alkaline medium. Significantly, the sulfur addition was found to be vital in improving materials’ catalytic performance through preventing aggregation of the nanospheres, constructing porous structures, increasing the surface area, and participating in the formation of active sites. 相似文献
6.
《International Journal of Hydrogen Energy》2019,44(31):16248-16256
A method has been developed to improve the hydrogen production efficiency (HPE) by in-liquid plasma n-dodecane decomposition. A thin steam pipe is placed over the plasma electrode to recover the thermal energy emitted from the plasma to its surroundings. The steam generated by this energy is supplied to the vaporized n-dodecane around the edge of the plasma to cause a steam reforming reaction (SRR). Water pyrolysis is suppressed by not supplying the steam directly to the plasma. A large amount of CO and a small amount of CO2 were detected in the produced gas. This indicates that a strong SRR has occurred. The HPE obtained by this method is 0.28 Nm3/kWh, which is two times greater than those obtained by previous methods, and similar to or greater than the yield of water electrolysis. This result is a major advance in the field of plasma heavy hydrocarbon decomposition aimed at hydrogen production. HPE is expected to be further improved by simply increasing the input power, due to synergy between the heat recovery effect of the steam pipe and the bubble stabilization effect. This indicates that this method has a high potential. 相似文献
7.
Xylan biopolymers are the dominant hemicelluloses present in agricultural plant materials which have potential use in various biotechnological processes including methane production. Hence, the effect of lignin content and the structural features of xylan on anaerobic digestion were studied by using synthetic assemblies consisting of xylans and lignin models (dehydrogenation polymers). The ramification by arabinose and uronic acid was shown to be a key factor in low methane potential (BMP) from xylans and xylan–lignin assemblies. Indeed, BMP increased when xylose content was increased, and decreased when arabinose and uronic acid contents were increased. Lignin content and molecular weight were found to be the most influential parameters on the anaerobic digestion rate. Digestion rate decreased when the lignin content and molecular mass increased. 相似文献
8.
《International Journal of Hydrogen Energy》2022,47(23):11955-11961
The operational flexibility of cryogenic batch distillation may propel its application in the Isotope Separation System of the fusion reactor. The batch distillation, unlike continuous distillation, is not a steady-state process. In order to obtain improved separation efficiency, a reasonable dynamic model of batch distillation should be developed. In this paper, dynamic simulations of the batch distillation separation process of a hydrogen-deuterium mixture were performed utilizing Aspen Plus and Aspen Dynamics. The validity of the established simulation model was firstly verified by our experimental results. Following that, two dynamic control structures, i.e., composition control and temperature control, were added to improve the recovery efficiency of batch distillation light component products. In comparison with the distillation without dynamic control structure, the distillation with composition control and temperature control can improve the H2 recovery ratio by 5.45% and 5.09%, respectively. 相似文献
9.
A hierarchically porous ZIF-67 was successfully synthesized by using non-ionic block copolymers P123 as a supramolecular templating surfactant and 1,3,5-trimethylbenzene (TMB) as a swelling agent. It was noted that TMB was an effective swelling agent to expand the pore size. Pore size distribution analyses reveal that the as-synthesized hierarchical ZIF-67 has a typical trimodal pore size distribution showing simultaneous micro-, meso- and macropore channel systems. Due to the effect of TMB and P123, the diameter of ZIF-67 nanoparticles was about twice of that synthesized with P123 only and larger pores were formed among the enlarged nanoparticles. This strategy is expected to be a facile and efficient method for the preparation of hierarchical ZIF-67. 相似文献
10.
Hui Zhang Yahia A. Alhamed Abdulrahim Al-Zahrani Mohammad Daous Hitoshi Inokawa Yoshitsugu Kojima Lachezar A. Petrov 《International Journal of Hydrogen Energy》2014
Multi-walled carbon nanotubes, three types of activated carbons, single wall carbon nanotube and reduced graphene oxides were used to synthesize nano-sized Co catalysts for H2 preparation via NH3 decomposition. Catalyst samples were characterized by number of techniques such as N2 physisorption, X-ray diffraction (XRD), X-ray photoelectron spectroscopes (XPS), Transmission electron microscopy (TEM), CO chemisorption, temperature-programmed reduction (H2-TPR) and temperature-programmed desorption (N2-TPD). The catalytic activities of the studied catalysts for H2 production via NH3 decomposition were measured in a fixed-bed micro-reactor. Co catalyst supported on multi-wall carbon nanotubes has shown the highest catalytic activity. The Co particles size was significantly affected by the variation of the post-treatment temperature. The Co particles size in the range of 4.7–64.8 nm can be effectively controlled by varying post-treatment temperature between 230 and 700 °C. The maximum TOF of NH3 decomposition was registered on cobalt catalyst post-treated at 600 °C. 相似文献