Hydrogen From Waste Metals

Hydrogen production by partial oxidation of methane over Co based, Ni and Ru monolithic catalysts

Προηγμένοι αντιδραστήρες μερικής οξείδωσης του μεθανίου προς αέριο σύνθεσης

Hydrogen is a commercially important element. Basically, there are several methods of hydrogen production that have been commercially used, such as Steam Methane Reforming (SMR), High Temperature Steam Electrolysis (HTSE), and thermochemical cycles, like Sulphur-Iodine (SI). Among these methods, SMR is the most widely used for large-scale hydrogen production, with conversion efficiency between 74–85% and it has commercially used in some fertilizer industries in Indonesia. Steam reforming is a method to convert alkane (natural gas) compounds to hydrogen and carbon dioxide (synthetic gas) by adding moisture at high pressure and temperature (35-40 bar; 800-900°C). These hydrogen production technologies can be coupled with different nuclear reactors based on the heat required in the process. The High Temperature Gas-cooled Reactor (HTGR) using helium as a coolant, has a high outlet temperature (900°C), so it can potentially be used to supply for process heat for hydrogen production, coal liquefaction/gasification or for other industrial processes requiring high temperature heat. Hydrogen production cost from SMR method is influenced by a range of technical and economic factors. The fuel component of natural gas needed in the SMR method can be replaced by nuclear heat from a nuclear power plant (NPP) operating in cogeneration mode (i.e. simultaneous producing electric power and heat), hence contributing to the reduction of carbon dioxide in the process.In the SMR method, fuel costs are the largest cost component, accounting for between 45% and 75% of production costs. Therefore, there is opportune to assess the economics of hydrogen production by using nuclear heat. The economic evaluation is done by using IAEA HEEP-4 Software.The results comprise cost break up for 2 cases, coupling SMR process for hydrogen production with: (1) 2 HTGRs of 170 MWth/unit; and (2) 1 HTGR of 600 MWth/unit. The cost of hydrogen production is highly depend on the scale of the NPP as energy source and results indicated that hydrogen production cost of the 1 HTGR Unit600 MWth (Case 2) has a lower value (1.72 US$/kgH2), than the cost obtained when 2 HTGR units of 170 MWth each (case 1) are considered (2.72 US$/kgH2). For comparison, the hydrogen production cost by using SMR with carbon capture and storage (CCS) with natural gas as fuel is 2.27 US$/kgH2.

A review on development of industrial processes and emerging techniques for production of hydrogen from renewable and sustainable sources

Microwave plasma-based method of hydrogen production via combined steam reforming of methane

Life cycle assessment of nuclear-based hydrogen and ammonia production options: A comparative evaluation

Hydrogen production from simple alkanes and oxygenated hydrocarbons over ceria–zirconia supported catalysts: Review

Hydrogen or synthesis gas production via the partial oxidation of methane over supported nickel–cobalt catalysts

Catalytic methane decomposition (CMD) is an environmentally friendly method of hydrogen production that, unlike other conventional processes, such as steam methane reforming, partial oxidation of methane, and dry reforming of methane, can convert methane into hydrogen with a simultaneous generation of solid carbon without CO2 emissions. This study mainly focused on the application of carbon-based catalysts derived from biomass and biowaste for the CMD process. For this purpose, eight catalysts were produced from three carbon materials (wood, sewage sludge, and digestate) through the subsequent processes of pyrolysis, leaching, and physical activation. The comparison of catalysts prepared from the slow pyrolysis of biowaste and wood indicated that carbon materials with a lower ash content achieved a higher initial methane conversion (wood char > digestate char > sewage sludge char). For feedstocks with a high initial ash content, such as digestate and sewage sludge chars, an improvement in the catalytic activity was observed after ash removal through the leaching process with HNO3. In addition, physical activation through CO2 fluxing led to an enhancement in the BET surface area of these catalysts, and consequently to a growth in methane conversion. The initial methane conversion was assessed for all chars under operating conditions of 900 °C, a gas hourly space velocity (GHSV) of 3 L/g/h, and a CH4:N2 ratio of 1:9, and it was 65.9, 59.1, and 42.6% v/v, respectively, for chars derived from wood, sewage sludge, and digestate; these values increased to almost 80% v/v when these chars were upgraded by chemical leaching and physical activation.

Interest in fuel cells in recent years has promoted the development of hydrogen sources. Methane (the main composition of natural gas) is an optimal fuel for hydrogen production due to its rich resource and its high ratio of hydrogen to carbon. In this work, several hydrogen processes, such as steam reforming of methane, partial oxidation, and auto thermal reforming, were reviewed. Different processes exhibit different importance for hydrogen production due to their diversity on usages. In this paper the special method of natural hydrogen production from natural gas with super adiabatic rich combustion is depicted in details. Some problems of this method were analyzed and discussed. In view of the existing problems, a new method was developed to be used for conversion of natural gas to hydrogen. The method can solve the problems of flame drift, heat preservation, product cooling, and low transform efficiency. Due to its simple and compact structure, it is attractive for distributing hydrogen production system and solving the transportation and storage problems of hydrogen.

Performance analysis of a feasible technology for power and high-purity hydrogen production driven by methane fuel

This work deals with the carbon dioxide cycle and emissions from biomass incineration under a hydrogen production context. It is proposed to use the thermal energy obtained by biomass combustion to produce water steam, which afterwards would be converted into hydrogen by high temperature electrolysis (HTE). In France, the thermal energy potential from nonvalorised biomass reaches almost 6.5 Mtep. In this study, the potential avoided carbon emissions are quantified as well as the feasible hydrogen production capacity based on the steam supplied by the incineration units. Results show that carbon consumption in hydrogen production by steam methane reforming (SMR) or biomass incineration-HTE process is almost equivalent between both processes. However, the hydrogen produced by the biomass incineration-HTE process used to fuel vehicles, would lead to a decrease of 135 Mt of carbon from fossil origins yearly, in contrast to SMR.

An evaluation of methanol production from natural gas by the conventional synthesis process shows that gas feedstock and capital charges are the dominant components of the methanol cost. Small but significant reductions In product cost can be made by increasing the conversion per pass and heat recovery from the synthesis reactor. However, the overall performance of the process is limited by the high cost and thermal Inefficiencies associated with the steam reforming step used to produce the synthesis gas. Catalytic partial oxidation (CPO) of methane directly to methanol has a potential advantage over the conventional process in that it eliminates the need for steam reforming. However, although considerable research has been conducted on CPO, no commercially viable process has yet been developed. An economic evaluation of a conceptual process for methanol production by CPO has been carried out assuming pure oxygen is used as oxidant. Results show that CPO has potential for reducing the coat of methanol provided the total oxidation of methane to CO2 and water Is minimised. On the criteria used In this evaluation, CPO is cheaper than synthesis when less than 23% of the methane is completely oxidised. Further research on CPO is warranted and should concentrate on maximising the selectivity of the reaction towards methanol formation.

CZTS/MoS2-rGO Heterostructures: An efficient and highly stable electrocatalyst for enhanced hydrogen generation reactions

The growing concern of many countries globally about the greenhouse gas emissions have emphasized interest towards dry reforming of methane (DRM). For an oil and gas based economy such as the state of Qatar, CO2 emission is a big challenge, as it has rendered Qatar as the highest CO2 emitting country per capita in the world. The potential of DRM process for integration in the existing infrastructure of Qatar is a key aspect of this research as a part of exceptional proposal granted to Dr. Nimir Elbashir by QNRF aimed at CO2 fixation. DRM is a heterogeneous chemical reaction in which the two greenhouse gases; CH4 and CO2 are converted to synthesis gas. Synthesis gas or ‘syngas’ is a precursor to a large variety of value added chemicals including hydrocarbons via Fischer-Tropsch Synthesis (FTS). In addition to CO2, steam can also be used to reform methane into syngas in a process known as steam reforming of methane (SRM). Steam Reforming of Methane (SRM) ΔH298 = 206 kJ/mol (1) Dry Reforming of Methane (DRM) ΔH298 = 247 kJ/mol (2) In addition to these two processes, there is also an exothermic reforming process, known as the partial oxidation of methane (POX), where methane is combusted to yield syngas. DRM process is beset by numerous major process limitations including its high endothermicity, high rate of catalyst deactivation (due to carbon formation) and low-quality syngas yield ratio (H2:CO⇐1:1). These challenges have posed severe obstruction towards widespread commercialization of this technique. A synergistic amalgamation of the reforming of methane as DRM+SRM, DRM+POX and DRM+SRM+POX have been recommended in the literature as a way to tackle the intrinsic limitations of the DRM process. In the current work, such combinations of methane reforming processes have been simulated thermodynamically using direct Gibbs free energy (GFE) minimization method. Energy valuations of various case scenarios have been carried out under varying operating conditions (temperature, presssure and feed mole ratios) assuming both ideal gas conditions and non ideal regimes using cubic equations of state (Peng Robinson (PR), Redlich Kwong (RK) and Soave Redlich Kwong). The main objective of the thermodynamics aspect of this study is to find optimized condition of reduced energy requirement and reduced carbon deposition while maintaining considerable CO2 fixation in a combined reforming process. In order to completely understand the system, a one-dimensional pseudo-homogeneous fixed bed reactor model which incorporates all the transport limitations (heat, mass and momentum) for combined SRM/DRM processes is developed. Reaction kinetics utilizing Langmuir-Hinshelwood Hougen-Watson (LHHW) type rate expressions published in the literature for SRM and DRM under analogous operating conditions have been used in the reactor bed model. These model results will be further validated against the experimental data published in literature. The kinetic conversion profiles are then compared with the thermodynamic results to systematically determine the regimes of kinetic deviation (from equilibrium) for the combined SRM/DRM system. This approach of carrying out both thermodynamic and reaction engineering analysis is advantageous in understanding the reforming process in a broader view and will also help in setting base for experimental investigations. These modeling results will be used as pre-experimental initial findings for the NPRP exceptional project aimed towards development of highly effective and coke resistant catalysts.ReferencesPakhare, D. and J. Spivey, A review of dry (CO2) reforming of methane over noble metal catalysts. Chemical Society Reviews, 2014. 43(22): p. 7813-7837.Song, C., Tri-reforming: a new process for reducing CO2 emissions. Chemical Innovation, 2001. 31: p. 21-26.Jiang H, Li H, Zhang Y., Tri-reforming of methane to syngas over Ni/Al2O3—thermal distribution in the catalyst bed. Journal of Fuel Chemistry and Technology 2007. 35: p. 72-78.Noureldin, M.M.B., N.O. Elbashir, and M.M. El-Halwagi, Optimization and Selection of Reforming Approaches for Syngas Generation from Natural/Shale Gas. Industrial & Engineering Chemistry Research, 2014. 53(5): p. 1841-1855.