共查询到20条相似文献,搜索用时 15 毫秒
1.
I. Martínez M.C. Romano P. Chiesa G. Grasa R. Murillo 《International Journal of Hydrogen Energy》2013
A detailed and comprehensive simulation model of a H2 production plant based on the Sorption Enhanced Reforming (SER) process of natural gas has been developed in this work. Besides thermodynamic advantages related to the shift of reforming equilibrium, SER technology features an intrinsic CO2 capture that can be of interest in environmentally constrained economies. The model comprises natural gas treatment, H2 and CO2 compression, as well as H2 purification with an adsorption unit that has been integrated within the SER process by using the off-gas for sorbent regeneration. A complete thermal integration has been also performed between the available hot gas streams in the plant, so that high pressure steam is generated and used to generate power in a steam cycle. 相似文献
2.
A. López Ortiz F.J. Neri Segura R. Sandoval Jabalera M. Marques da Silva Paula E. Arias del Campo J. Salinas Gutiérrez M.A. Escobedo Bretado V. Collins-Martínez 《International Journal of Hydrogen Energy》2013
Biomass pyrolysis offers a fast route to produce elevated yields towards highly valued liquid products. This research aims the determination of optimal experimental conditions for a slow and low temperature pyrolysis to produce the highest yield towards condensable (CVM) and non-condensable (NCVM) volatile matter from Mexican cane bagasse and to quantify and characterize the compounds that constitute CVM and NCVM obtained. Results indicate that yield towards volatiles is strongly dependent on temperature. The highest yield was achieved at temperatures greater than 500 °C at a heating rate of 10 °C/min, residence time of 60 min and a particle size between of 420 and 840 μm. Product quantification under isothermal conditions determined that at 550 °C the NCVM, CVM and solid residue was of 26, 57 and 16%, respectively. Preliminary thermodynamic analysis of steam reforming and CO2 absorption reactions using one of the main CVM products resulted in a potential high hydrogen production yield. 相似文献
3.
Binlin Dou Chao Wang Haisheng Chen Yongchen Song Baozheng Xie 《International Journal of Hydrogen Energy》2013
In this study, the continuous sorption-enhanced steam reforming of glycerol to high-purity hydrogen production by a simultaneous flow concept of catalyst and sorbent for reaction and regeneration using two moving-bed reactors has been evaluated experimentally. A Ni-based catalyst (NiO/NiAl2O4) and a lime sorbent (CaO) were used for glycerol steam reforming with and without in-situ CO2 removal at 500 °C and 600 °C. The simultaneous regeneration of catalyst and sorbent was carried out with the mixture gas of N2 and steam at 900 °C. The product gases were measured by a GC gas analyzer. It is obvious that the amounts of CO2, CO and CH4 were reduced in the sorption-enhanced steam reforming of glycerol, and the H2 concentration is greatly increased in the pre-CO2 breakthrough periods within 10 min both 500 °C and 600 °C. The extended time of operation for high-purity hydrogen production and CO2 capture was obtained by the continuous sorption-enhanced steam reforming of glycerol. High-purity H2 products of 93.9% and 96.1% were produced at 500 °C and 600 °C and very small amounts of CO2, CH4 and CO were formed. The decay in activity during the continuous reaction-regeneration of catalyst and sorbent was not observed. 相似文献
4.
María Ortiz Pilar GayánLuis F. de Diego Francisco García-LabianoAlberto Abad Miguel A. PansJuan Adánez 《Journal of power sources》2011,196(9):4370-4381
In this work it is analyzed the performance of an iron waste material as oxygen carrier for a chemical-looping combustion (CLC) system. CLC is a novel combustion technology with the benefit of inherent CO2 separation that can be used as a source of energy for the methane steam reforming process (SR). The tail gas from the PSA unit is used as fuel in the CLC system.The oxygen carrier behaviour with respect to gas combustion was evaluated in a continuous 500 Wth CLC prototype using a simulated PSA off-gas stream as fuel. Methane or syngas as fuel were also studied for comparison purposes. The oxygen carrier showed enough high oxygen transport capacity and reactivity to fully convert syngas at 880 °C. However, lower conversion of the fuel was observed with methane containing fuels. An estimated solids inventory of 1600 kg MWth−1 would be necessary to fully convert the PSA off-gas to CO2 and H2O. An important positive effect of the oxygen carrier-to-fuel ratio up to 1.5 and the reactor temperature on the combustion efficiency was found.A characterization of the calcined and after-used particles was carried out showing that this iron-based material can be used as oxygen carrier in a CLC plant since particles maintain their properties (reactivity, no agglomeration, high durability, etc.) after more than 111 h of continuous operation. 相似文献
5.
A compact and high-efficiency electrified reactor for hydrogen production by methane steam reforming
《International Journal of Hydrogen Energy》2022,47(98):41421-41431
An electrified reactor driven by renewable electricity, substituting conventionally fired reactors, will reduce CO2 and provide a compact manner for hydrogen generation. Herein, we proposed a high-efficiency electrified reactor based on a high-temperature heat pipe (HTPR). The start-up of the HTPR powered by electricity was firstly evaluated, showing a start-up duration of 250 s and maintaining significant temperature uniformity of 96.7%. Then, the feasibility and performance of the HTPR were validated by experiments. The methane conversion and hydrogen mole fraction were 80.0% and 70.5% at a steam to carbon ratio of three, respectively. Finally, the reaction performance under different operating conditions was simulated. The methane conversion and the hydrogen mole fraction were attenuated with the increase in flow rate, and improving catalyst porosity is beneficial for the heat transfer between catalysts and gases. This study serves as a framework for designing an electrified reactor for endothermic reactions. 相似文献
6.
Miguel A. Pans Alberto AbadLuis F. de Diego Francisco García-LabianoPilar Gayán Juan Adánez 《International Journal of Hydrogen Energy》2013
Methane steam reforming (SR) integrated with a chemical-looping combustion (CLC) system is a new process for producing hydrogen from natural gas, allowing carbon dioxide capture with a low energy penalty. In this study, mass and enthalpy balances of an SR-CLC system were carried out to determine the autothermal operating conditions for optimal H2 production. The evaluation was conducted using iron-based oxygen carriers. Two configurations were analysed, firstly with the reformer tubes inside the fuel reactor and, secondly, with the reformer tubes inside the air reactor. This paper analyses the effect of two parameters affecting the SR process, namely the conversion of methane in the reformer (XCH4) and the efficiency of the hydrogen separation of a pressure swing adsorption (PSA) unit (ηPSA), as well as two parameters affecting the CLC system, namely the Fe2O3 content in the oxygen carrier and its conversion variation (ΔXOC), on the H2 yields. Moreover, it also analyses the reduction of Fe2O3 to Fe3O4 or to FeAl2O4. The results shown that a H2 yield value of 2.45 mol H2 per mol of CH4 can be obtained with the reformer tubes located inside the air reactor and with Fe2O3 being reduced to Fe3O4. This corresponds to a CH4 to H2 conversion of 74.2%, which is similar to state-of-the-art H2 production technologies, but with inherent CO2 capture in the SR-CLC process. 相似文献
7.
Bo Chen Zuwei LiaoJingdai Wang Huanjun YuYongrong Yang 《International Journal of Hydrogen Energy》2012
This paper investigates the industrial production of hydrogen through steam methane reforming (SMR) from both exergy efficiency and CO2 emission aspects. An SMR model is constructed based on a practical flow diagram including desulfurizer, furnace, separation unit and heat exchangers. The influence of reformer temperature (Tr) and steam to carbon (S/C) ratio is analyzed to optimize exergy efficiency and CO2 emission. A clear correlation is obtained between exergy efficiency and CO2 emission. Results also show optimal S/C ratio decreases with Tr. An exergy load distribution analysis which evaluates interactions between the system and its subsystems with parameter variations is employed to find promising directions for efficiency improvement. Results show that the greatest improvement lies in increasing efficiency of furnace without increasing its relative exergy load. Integration of oxygen-enriched combustion (OEC) with SMR is also evaluated. The integration of OEC can increase the system efficiency greatly when the reformer operates above critical point, while in other cases the system efficiency may decrease. 相似文献
8.
The production of hydrogen combined with carbon capture represents a possible option for reducing CO2 emissions in atmosphere and anthropogenic greenhouse effect. Nowadays the worldwide hydrogen production is based mainly on natural gas reforming, but the attention of the scientific community is focused also on other gas mixtures with significant methane content. In particular mixtures constituted mainly by methane and carbon dioxide are extensively used in energy conversion applications, as they include land-fill gas, digester gas and natural gas. The present paper addresses the development of an innovative system for hydrogen production and CO2 capture starting from these mixtures. The plant is based on steam methane reforming, coupled with the carbonation and calcination reactions for CO2 absorption and desorption, respectively. A thermodynamic approach is proposed to investigate the plant performance in relation to the CH4 content in the feeding gas. The results suggest that, in order to optimize the hydrogen purity and the efficiency, two different methodologies can be adopted involving both the system layout and operating parameters. In particular such methodologies are suitable for a methane content, respectively, higher and lower than 65%. 相似文献
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10.
Hydrogen production via steam reforming of ethyl alcohol over nano-structured indium oxide catalysts
Tetsuo Umegaki Kentaro KurataniYusuke Yamada Atsushi UedaNobuhiro Kuriyama Tetsuhiko KobayashiQiang Xu 《Journal of power sources》2008
Mesoporous and worm-like In2O3 catalysts have been prepared using KIT-6 and MCM-41 silicas as templates, which show low crystallinities and high surface areas. Compared with commercial In2O3 catalyst with low surface area, these two nano-structured In2O3 catalysts exhibit higher catalytic activity for steam reforming of ethyl alcohol at low temperature to produce hydrogen containing no detectable CO impurity, presenting an advantage in comparison with the previous reported catalysts. 相似文献
11.
Equilibrium shifting is considered to be effective for promoting H2 production by methane (CH4) steam reforming. In this study, a packed bed reactor with a mixture of reforming catalyst and CO2 absorbent was used. Pellets of lithium silicate (Li4SiO4), which Toshiba has developed, were applied as the absorbent. This is a report on the relationship between CO2 absorption by Li4SiO4 pellets and the equilibrium-shift effect for overall reactions. Experiments showed that there was a strong influence of temperature on the equilibrium-shift effect. The effect was obvious, which resulted in keeping not only the concentration of H2 above 93 vol% but also that of CO below 0.2 vol% at 550 °C. 相似文献
12.
A.A. Iordanidis P.N. Kechagiopoulos S.S. Voutetakis A.A. Lemonidou I.A. Vasalos 《International Journal of Hydrogen Energy》2006
A concept of sorption-enhanced steam reforming of bio-oil/biogas for electricity and heat generation by phosphoric acid fuel cells is investigated. The process is modeled using SIMSCI Pro II process simulator. Sorptive removal of the carbon dioxide from the reaction site results in low CO and CO2 concentrations (<1%) in the reformate, as a result it can be used in the phosphoric acid fuel cell without any further fuel cleanup. High hydrogen concentration and calorific value of the reformate enable the operation of the fuel cell at a high-efficiency mode despite of the high carbon/hydrogen ratio of the bio-fuel. Addition of biogas to the reformer enables autothermal operation of the reformer, as well as significantly improves the efficiency of the process. The simulation shows that the overall efficiency of the proposed system is compatible with the efficiency of the system using “classical” steam reforming of the fuel. The process exhibits 6% lower electrical efficiency compared to the system utilizing natural gas, and 4.6% higher efficiency compared to a system using bio-oil as a fuel. 相似文献
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14.
Muhammad Syukri Abd Rahaman Li-Hua Cheng Xin-Hua Xu Lin Zhang Huan-Lin Chen 《Renewable & Sustainable Energy Reviews》2011,15(8):4002-4012
The capture of carbon dioxide (CO2) from the air for microalgal cultivation has received increasing interest since it allows advantages that do not only reduce the amount of CO2 already added to the air, but it is also more economical due to the accessibility of air, there are no regeneration requirements and it is a safe method that can help enhance microalgal growth. In order to capture CO2 from the air, it is necessary to deal with CO2 emissions from all sources in an atmosphere. Interestingly, the capture unit and microalgal culture can be located at any favorable site. Although a number of photobioreactors have been proposed with a CO2 distribution system, the consequence of CO2 losses is still being ignored. Thus, capturing CO2 from the air via an integrated separation process in a photobioreactor is required for microalgal cultivation. Among the four available separation technologies, the membrane separation process would offer a safe, reliable and low cost method for CO2 capture. Thus, this method of separation can be considered as a key factor in accelerating the development of a CO2 enrichment process from the air for microalgal cultivation. 相似文献
15.
Yinxiang Wang Muhammad Zaki Memon Majid Ali Seelro Weng Fu Yuan Gao Yingchao Dong Guozhao Ji 《International Journal of Hydrogen Energy》2021,46(45):23358-23379
Sorption-enhanced-steam-reforming (SESR) is a thermochemical conversion technology that produces a high-purity hydrogen stream by utilizing in-situ removal of CO2 with a sorbent. In this paper, the advantages and disadvantages of CaO based sorbents, alkali-metal based sorbents (Na2ZrO3, Li2ZrO3 and Li4SiO4), hydrotalcite based sorbents, bifunctional materials and sorbents prepared from wastes are briefly discussed, and the techniques to improve the sorption properties of these CO2 sorbents are summarized. In the process of hydrogen production by sorption-enhanced-steam-reforming, the selection of suitable high-temperature CO2 sorbent is the key to produce high purity hydrogen. Furthermore, the hydrogen-production performance of the above-mentioned sorbents in the SESR process is investigated and summarized. Finally, a future perspective and some suggestions regarding these five types of sorbents are put forward. 相似文献
16.
Thermodynamics equilibrium analysis of carbon dioxide reforming of methane combined with steam reforming to synthesis gas was studied by Gibbs free energy minimization method to understand the effects of process variables such as temperature, pressure and inlet CH4/H2O/CO2 ratios on product distributions. For this purpose, the calculations were carried out at total pressures of 1 and 20 bar, and at ranges of temperature and steam-to-carbon ratios of 200–1200 °C and 0–0.50, respectively. The results revealed that carbon dioxide reforming of methane combined with steam reforming process was controlled by different reactions with regard to the operating temperature, pressure and varying feed compositions. The H2/CO product ratio could be modified by changing the relative concentration of steam and CO2 in the feed, temperature and pressure, depending on the downstream application. 相似文献
17.
The steam reforming of pyrolysis bio-oil is one proposed route to low carbon hydrogen production, which may be enhanced by combination with advanced steam reforming techniques. The advanced reforming of bio-oil is investigated via a thermodynamic analysis based on the minimisation of Gibbs Energy. Conventional steam reforming (C-SR) is assessed alongside sorption-enhanced steam reforming (SE-SR), chemical looping steam reforming (CLSR) and sorption-enhanced chemical looping steam reforming (SE-CLSR). The selected CO2 sorbent is CaO(s) and oxygen transfer material (OTM) is Ni/NiO. PEFB bio-oil is modelled as a surrogate mixture and two common model compounds, acetic acid and furfural, are also considered. A process comparison highlights the advantages of sorption-enhancement and chemical looping, including improved purity and yield, and reductions in carbon deposition and process net energy balance.The operating regime of SE-CLSR is evaluated in order to assess the impact of S/C ratio, NiO/C ratio, CaO/C ratio and temperature. Autothermal operation can be achieved for S/C ratios between 1 and 3. In autothermal operation at 30 bar, S/C ratio of 2 gives a yield of 11.8 wt%, and hydrogen purity of 96.9 mol%. Alternatively, if autothermal operation is not a priority, the yield can be improved by reducing the quantity of OTM. The thermodynamic analysis highlights the role of advanced reforming techniques in enhancing the potential of bio-oil as a source of hydrogen. 相似文献
18.
J. Kim H. Choi J. Lim Y. Rhim D. Chun S. Kim S. Lee J. Yoo 《International Journal of Hydrogen Energy》2013
The kinetics of the coal to hydrogen conversion can be significantly enhanced by introducing catalysts. The catalysts are, however, commonly deactivated by irreversible interaction with mineral matters in coal. This work addresses hydrogen production via steam gasification of ash free coals. Following the production of ash free coals (AFCs) derived from various raw coals (brown, bituminous, and coking coal), fixed-bed steam gasification of the AFCs was performed as a function of temperature and which was compared with one another and also with that of the matching raw coals. In the absence of a catalyst, AFCs produced from different parent coals exhibited similarly low gasification reactivity, comparable to a high rank coal (coking coal) at 700 °C. As expected, the reaction became faster with increasing temperature in the range, 700–900 °C. The steam gasification of AFCs was highly activated by K2CO3 above 700 °C. It was very likely that water–gas shift reaction associated with the gasification of AFCs was also catalyzed. 相似文献
19.
The catalytic decomposition of methane into hydrogen and carbon was studied on La2O3 doped Ni and Ni–Cu Raney-type catalysts. The activity and stability of the catalysts were assessed by comparing the experimental conversions with the calculated equilibrium conversions for each set of experimental conditions, and the maximum conversions with the conversions at the end of (at least) 5 h tests, respectively. Improved stability of La2O3 doped catalysts was ascribed to an electronic promotion effect. There is an optimum load of the promoter, which provides for extended periods of stable catalyst operation. The carbon deposits consist of carbon nanofibers and multiwall carbon nanotubes. The La2O3 doped Ni–Cu Raney-type catalysts presented in this work are remarkably efficient for the production of hydrogen by methane decomposition. 相似文献
20.
The coal gasification process is used in commercial production of synthetic gas as a means toward clean use of coal. The conversion of solid coal into a gaseous phase creates opportunities to produce more energy forms than electricity (which is the case in coal combustion systems) and to separate CO2 in an effective manner for sequestration. The current work compares the energy and exergy efficiencies of an integrated coal-gasification combined-cycle power generation system with that of coal gasification-based hydrogen production system which uses water-gas shift and membrane reactors. Results suggest that the syngas-to-hydrogen (H2) system offers 35% higher energy and 17% higher exergy efficiencies than the syngas-to-electricity (IGCC) system. The specific CO2 emission from the hydrogen system was 5% lower than IGCC system. The Brayton cycle in the IGCC system draws much nitrogen after combustion along with CO2. Thus CO2 capture and compression become difficult due to the large volume of gases involved, unlike the hydrogen system which has 80% less nitrogen in its exhaust stream. The extra electrical power consumption for compressing the exhaust gases to store CO2 is above 70% for the IGCC system but is only 4.5% for the H2 system. Overall the syngas-to-hydrogen system appears advantageous to the IGCC system based on the current analysis. 相似文献