Reformate Gas Research Articles

A Thermodynamic Analysis of Heavy Hydrocarbons Reforming for Solid Oxide Fuel Cell Application as a Part of Hybrid Energy Systems

A thermodynamical analysis of steam reforming of Associated Petroleum Gas (APG) was conducted in the presented research. The reforming process of heavy hydrocarbons for small scale power generation is a complex issue. One of the main issues is that a set of undesired chemical reactions deposit solid carbon and, consequently, block the reactor’s catalytic property. The experimental investigation is crucial to design an APG reforming reactor. However, a numerical simulation is a key tool to design a safe operating condition. Designing the next generation of reactors requires a complex coupling of mathematical models, kinetics, and thermodynamic analysis. In practice, the thermodynamic analysis should be applied in each control volume to assure realistic results. This is not easy to apply in practice since both thermodynamic analysis and CFD modeling can be time-consuming. In this paper, the authors suggest using a mathematical formalism called Parametric Equation Formalism to calculate the equilibrium composition. The novelty lies in the mathematical approach in which any complex system at equilibrium can be reduced to the problem of solving one non-linear equation at a time. This approach allows implementing a thermodynamic analysis easily into CFD models to assure the reasonability of obtained results and can be used for research and development of solid oxide fuel cells as a part of hybrid energy systems.

Experimental study on characteristics of hydrogen production from exhaust gas-fuel reforming in a catalytic fixed-bed reactor

Since the hydrogen-rich gas can be generated on-board by the catalytic reforming of exhaust gas from the engine, reformed exhaust gas-fuel recirculation is an attractive method for waste-heat recuperation and performance enhancement for the engines fueled by natural gas (NG). In the present study, the industrial Ni/Al2O3 catalyst was selected to investigate the effects of wall temperature, feed ratio and gas hourly space velocity (GHSV) on hydrogen production from exhaust gas-fuel reforming in a catalytic fixed-bed reactor. Meanwhile, Ni/Al2O3 fresh catalyst was characterized by the X-ray diffraction (XRD), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS) techniques. The simulated exhaust gas was prepared based on the exhaust gas from a marine NG engine at 75% propeller load. The experimental results show that the higher wall temperature is favored for steam reforming to deliver higher H2 concentration in the reformate gas, which result in the increase of the H2 volume fraction at reformer outlet, H2 yield and CH4 conversion with the wall temperature. The maximum values of H2 yield and H2 volume fraction from the reformer outlet can reach up to approximately 0.96 and 22%, respectively. From the view of reforming process, that CH4/O2 = 2 and H2O/CH4 = 2 is considered as the optimum matching feed ratio. When a GHSV is approximately 7500 h−1, the H2 volume fraction at reformer outlet can be maximized. Under the given conditions, a more preferable reforming energy efficiency can be achieved when H2O/CH4 = 2, CH4/O2 = 3, GHSV = 6000 h−1 and high wall temperature.

Simulating the steam reforming of sunflower meal in Aspen Plus

Hydrogen is a clean energy carrier that has the potential to mitigate the environmentally hazardous effects of fossil fuels. Hydrogen is mainly produced through the steam reforming of natural gas however it is also possible to produce hydrogen through the thermochemical conversion of various biomasses. In this study, three Aspen plus simulation models were developed to obtain hydrogen-rich gas products from biomass through catalytic steam reforming. The results obtained in this modeling study were compared to the experimental data obtained by the steam reforming of the sunflower meal, which is a waste product of the seed oil industry. Out of all three models, model II, in which all of the reactions are assumed to occur simultaneously and all species except for biomass are assumed to undergo combustion reactions, was the most successful one at predicting close results (93% similar) to experimental findings. Using this model, the effect of water:biomass feed ratio on the product yields was tested and the highest possible H2 yield (44.9 mol H2/kg sunflower meal) was achieved with a 15:1 water:biomass feed ratio at the constant temperature of 800 °C and atmospheric pressure.

FORENSIC INVESTIGATION OF PETROLEUM COMPONENTS OF MIXED MOTOR GASOLINES

The main types of petroleum components that are used in the manufacture of mixed motor gasolines are considered. For the manufacture of mixed motor gasolines, a low-octane base is used, to which high-octane components are added. In many cases, reformate (catalytic reforming gasoline) and isopentane (isopentane fraction) are used as high-octane components of mixed motor gasolines. Straight-run gasoline and stable gasoline are often used as the low-octane gasoline base of blended automobile gasolines. Reformate is a liquid mixture of aromatic and saturated hydrocarbons used as a high-octane component of automobile (aviation) gasolines and raw materials in the production of aromatic hydrocarbons (arenas). The reformate is obtained by catalytic reforming of straight-run gasoline fractions. Isopentane (2-methylbutane (CH3)2CHCH2CH3) is a colorless, flammable liquid. The technical product is a mixture of isomeric pentanes and boils within 24 - 34°C. The isopentane fraction can be isolated from gas gasoline, from gasoline direct distillation of oil and gasoline catalytic cracking. Straight-run gasoline (nefras) is obtained from the processing of crude oil or gas condensate, oil shale or coal, natural gas or oil and gas. Straight run gasoline contains light gasoline fractions of direct distillation of oil with a boiling range of 35 - 180°C. Gas gasoline (gas stable gasoline) is obtained from natural and petroleum gases containing vapors of gasoline hydrocarbons. To separate them, the gases are compressed and cooled (compression method) or absorbed with oil or activated carbon. Gas gasoline is similar in chemical composition to straight-run gasoline, but contains lighter hydrocarbon fractions. The article discusses the results of a study of the listed petroleum components of mixed gasoline by gas-liquid chromatography. This method allows you to establish the qualitative and quantitative composition of mixed motor gasolines and their components. It is shown that from readily available petroleum components (isopentane fraction, aromatic hydrocarbons and gas stable gasoline) without the use of sophisticated technological equipment, a gasoline mixture with high detonation resistance, which is falsified automobile gasoline, can be obtained by mixing method. When mixed in certain proportions of reformate, isopentane fraction and gas stable gasoline, it is possible to obtain marketable gasoline that will meet the requirements of regulatory documents for gasoline. The considered technology allows, when mixing commodity gasolines A-92 (A-95) with reformate, isopentane fraction and gasoline gas stable in the calculated proportions, to improve the operational characteristics (detonation resistance) of the obtained gasoline mixture or to increase the volume of the obtained gasoline mixture without improving its performance.

低温酸化反応を用いた軽油改質技術によるHC-SCR の開発

低温酸化反応を用いた軽油改質技術によるHC-SCR の開発

Pyrolysis Gas from Biomass and Plastics Over X-Mo@Mgo (X=Ni, Fe, Co) Catalysts into Functional Carbon Nanocomposite: Gas Reforming Reaction and Proper Process Mechanisms

Pyrolysis Gas from Biomass and Plastics Over X-Mo@Mgo (X=Ni, Fe, Co) Catalysts into Functional Carbon Nanocomposite: Gas Reforming Reaction and Proper Process Mechanisms

Hydrogen steelmaking. Part 1: Physical chemistry and process metallurgy

Pushed to the forefront by the objective to drastically reduce the CO2emissions from the steel industry, a new steelmaking route based on hydrogen and electricity is the subject of a great deal of attention and numerous R&D projects. The first step is to chemically reduce iron ore with H2, which is produced by electrolysis of water with low-carbon electricity, and then to transform the direct reduced iron into steel in an electric arc furnace. The second step is a conventional one, similar to that used for scrap recycling. The first step is similar to the so-called direct reduction process but would use pure electrolytic H2instead of the H2–CO syngas obtained from natural gas reforming. In this paper, we first show how the reduction by pure H2takes place at the microscopic level of the iron oxide grains and pellets. The three-step (hematite-magnetite-wüstite-iron) reduction occurs successively in time and simultaneously in the pellets. Secondly, a sophisticated kinetic model of the reduction of a single pellet based on the experimental findings is described. Lastly, we present a mathematical model for the simulation of the reduction by pure H2in a shaft furnace, which can be very useful for the design of a future installation. The main results are that using pure hydrogen, the reduction kinetics are faster and can end with full metallization, the direct reduction process would be simpler, and the shaft furnace could be squatter. The gains in terms of CO2emissions are quantified (85% off) and the whole route is compared to other zero-carbon solutions in Part 2.

Power-to-Gas, Hydrogen, and a Spotlight on New York's Emerging Climate and Energy Policy

This paper examines the role of law and regulation in advancing technology-based energy decarbonization options such as hydrogen compatible networks and power-to-gas (P2G) in the context of New York’s energy and climate change mitigation goals. By exemplifying the potential of P2G and hydrogen, it underscores the need for a more comprehensive legal and regulatory framework that (i) reflects the peculiarities of gas and electricity systems (on the one hand) and (ii) facilitates a more effective and integrated energy decarbonization pathway (on the other hand). Hydrogen is an energy carrier with a significant potential to deliver zero and low-carbon energy depending on how it is produced. Also, when combined with oxygen in a fuel cell, hydrogen produces heat and electricity with only water vapor as a by-product. It has been used for several years in bespoke applications in the aeronautics, industrial, and transportation sectors. About ten million metric tons of hydrogen is currently produced in the US every year, and ninety-five percent of which is via centralized reforming of natural gas (i.e. steam methane reformation (SMR) and known as “Blue Hydrogen”) used mostly in petroleum refining and ammonia industries. Other modes of utilization include fuel cell vehicles, metals refining, and synthetic natural gas production. Notably, the P2G process leads to the production of “green hydrogen” by using electricity that would otherwise be curtailed or lost, from variable renewable energy (VRE) sources such as solar and wind. Such VRE sourced energy can be used to split water into its hydrogen and oxygen components. The ‘green hydrogen’ process is becoming increasingly relevant to the issues of (i) decarbonization of gas and electricity networks; and (ii) solving the ‘curtailment’ ‘intermittency’ and ‘storage’ challenge in an energy system where renewables are gradually playing a larger role. It may also be key to facilitating the integration of a growing share of VREs in existing networks and in the same vein helping to avoid the ‘stranded assets’ dilemma faced by operators of natural gas pipeline and storage networks which can be compatible with hydrogen or synthetic methane produced as a result. Law and regulation provide a facilitative means through which relevant institutions and operators can work towards decarbonization and develop the requisite technology-based solutions while addressing the energy policy challenges created by the increasing role of VREs. Such considerations are even more relevant for a state such as New York. Even though the state’s Clean Energy Standard revised in 2019 requires 100% carbon-free electricity by 2040; in 2019, 29% of New York's in-state generation came from renewable sources. One-third of its utility-scale net generation came from in-state nuclear power plants that are scheduled to be decommissioned soon, while it was the sixth-largest natural gas consumer in the US, and three in five households used natural gas for home heating. The emerging energy decarbonization issues can be met if, among other things, law and regulation are viewed from a functional lens. In this regard, ‘regulation’ is considered as part of a legal framework that is instrumentalist in orientation with the aim of pursuing defined energy policy objectives which typically comprise of ensuring (i) secure and reliable supplies, (ii) sustainability while protecting the environment, and (iii) ensuring that costs and rates are just and reasonable both for the suppliers and consumers. The (ii) dimension is crucial in a carbon-constrained world. Thus, the paper will consider these highlighted issues and in Part II discuss the growth and challenges with VREs in the US energy mix and then highlight potential role(s) for hydrogen and P2G as an example of innovative technology-based decarbonization solution as well as a means of efficiently integrating growing VREs in electricity context with natural gas networks. Part III will examine the regulatory issues in the regulation of gas and electricity systems in a carbon-constrained world and the challenges and potential for decarbonization by deploying hydrogen and P2G. Part IV examines New York’s emerging climate and energy regulation framework and points out the possible issues with deploying P2G and hydrogen in the state. The paper concludes by highlighting that in the pathways to decarbonization the overarching objective in determining how and what to regulate should be ‘curbing greenhouse gas emissions’. It also underscores the need to develop an integrated policy and regulatory framework that can enhance the required technologies and energy systems in the path towards decarbonization.

Source and accumulation processes of natural gases in the Qixia Formation in the Northwestern Sichuan Basin, SW China

The Northwestern Sichuan Basin is a hot spot for natural gas exploration, and in recent years, many wells have obtained high-yield commercial gas flows in the Qixia Formation. However, due to the influence of foreland orogeny, the oil and gas in the Qixia Formation often have the characteristics of multisource filling, multistage accumulation and multistage transformation, which results in an unclear understanding of the gas source and the accumulation process. This paper uses the concept of sub-block research through carbon isotope and biomarkers analyses, to carry out gas-gas, gas-source and bitumen-source rock comparisons in different structural belts to determine the natural gas sources. On this basis, basin simulation and fluid inclusion analysis technology are used to determine the stage of hydrocarbon accumulation, and then the accumulation process is determined. Studies have shown that the gas source of the Qixia Formation are different in the different structural belts: (1) The natural gas from the Qixia Formation in the thrust nappe belt mainly originates from the Qiongzhusi Formation source rock; (2) The natural gas from the Qixia Formation in the hidden fault belt is a mixture of the source rock of the Qixia Formation and the source rock of the Qiongzhusi Formation; and (3) The natural gas from the Qixia Formation in the gentle belt mainly originates from the Middle Permian source rock and the Upper Permian Longtan Formation source rock. The Indosinian, Yanshania, and Himalayan movements all have great influence on the formation of the Qixia Formation reservoir in northwestern Sichuan, and the accumulation process of the different structural belts is quite different, but generally, the accumulation process of the different structural belts have experienced three stages: a primary oil pool stage, gas pool stage and reformation and definition stage.

Hydrogen production by methane steam reforming using metallic nickel hollow fiber membranes

The metallic nickel hollow fiber membranes (NHFMs) consisting of a dense skin layer integrated on porous nickel substrate were fabricated in a single extrusion step by using a 90 wt% NMP-H2O solution and water as the respective internal and external coagulants during the spinning process. The resultant asymmetric Ni hollow fibers by sintering were directly applied to hydrogen production from methane steam reforming (MSR), where the porous internal surface functioned as a catalyst bed for MSR reactions, and the external dense skin layer served as the membrane for hydrogen extraction from the reaction products. The effects of the feed composition in terms of steam-to-methane ratio (H2O/CH4) and methane concentration; the operational parameters including temperature, space velocity, and the sweep gas flow rate on the performance of the hollow fibers were investigated. The results reveal that the reaction operational temperature should be above 800 °C and the H2O/CH4 ratio controlled around 3 so as to achieve both high methane conversion and high H2 production rate. When operated at 1000 °C and 25,937 h−1 methane space velocity, the maximum H2 production rate reached 50.84 mmol m−2 s−1 while the methane conversion reached at 98.58%. In order to produce pure hydrogen, steam may be used as the sweep fluid instead of inert gases such as nitrogen to prevent the dilution of the permeated gaseous hydrogen. The prepared asymmetric NHFMs also demonstrate high chemical stability in the reformate gases and high resistance to carbon deposition at above 800 °C, and thus may be a promising way of cost-effective hydrogen production by MSR at high temperatures.

Improving the HER Kinetics of the Nickel Phosphide Catalyst Using Electrochemical Dealloying Treatment

Hydrogen fuel is receiving a lot of attention owing to its high efficiency and eco-friendliness. The reforming of natural gas is conventionally used to generate hydrogen gas; however, the process generates carbon dioxide causing global warming. To solve the problem, water electrolysis, which produces hydrogen and oxygen gas from water, is actively studied in order to design a cheaper and more effective hydrogen generation system.The major research gap of water electrolysis is the high cost due to the rarity of catalyst materials such as platinum [1,2]. As a substitute for a platinum catalyst, transition metal phosphides represented by nickel phosphide (Ni-P) has shown the comparable catalytic activity to platinum, despite the much lower cost compared to platinum. The nickel phosphide can be fabricated with a facile electroplating process which can be more suitable synthesis process of electrocatalyst, because it is not necessary to mix with a polymer such as Nafion, disturbing emission of generated gas and decreasing surface area [3]. On the other hand, the nickel phosphide has showed low stability in acid media. According to the previous researches [4], the main reason of low stability is due to the difference of corrosion potential between nickel metal and Ni-P phases. Furthermore, they suggest three strategies to increase the corrosion resistance: (i) well-alloying of nickel and phosphorus, (ii) formation of amorphous film at grain boundary, and (iii) formation of phosphate passive film on the surface [4].In this context, we adopted the electrochemical surface treatment for the electroplated Ni-P to improve the activity and stability of Ni-P/carbon paper (CP) catalyst. The surface treatment (“dealloying surface treatement”) is to remove the ‘isolated Ni’ which has less bonding with P, which is composed of the CV cycles inducing the repetition of oxidation and reduction of Ni-P/CP catalyst. Furthermore, it is expected to form well-alloying between nickel and phosphide (recrystallization of Ni-P).As a result, the morphology of Ni-P/CP after CV 20 cycles was similar with raw Ni-P/CP as shown in Fig. 1a, b. However, an area of P-rich portion (dark part) increased after dealloying cycles. Therefore, an atomic ratio of phosphorus increased about 186% higher after 20 cycles of CV than the Ni-P/CP which did not conduct surface treatment. In addition, the more invasion of phosphorus atom aroused a decrease of grain size of nickel metal (Fig. 1c). According to XPS data of Ni state in Fig. 1d, an intensity of peak at a binding energy of 853 eV which means a bonding of Ni2P increased after the dealloying process. That is, the bonding between Ni and P atoms increased after the treatment. An atomic ratio of P at the surface was also increased to 36.54at%, since Ni-P/CP catalyst showed 24.88at% of P. As a result, a repetition of reduction and oxidation of Ni-P during the dealloying surface treatment decreases the cystalline size of Ni and increase the P content of the Ni-P catalyst.Due to such the changes, the Ni-P/CP showed a higher activity and stability after the dealloying surface treatment. Specifically, Ni-P/CP after CV 20 cycles showed the highest HER activity, with the overpotential of 124 mV at the current density of 10 mA cm-2, since raw Ni-P/CP had the overpotential of 179 mV (Fig. 2a). And then, the current density for Ni-P/CP after CV 20 cycles was maintained at approximately 80.4% at −0.2 VRHE for 6 hours, while raw Ni-P/CP maintained a current density of 35.6%. It is presumably because the nickel atoms can use enough electrons for the HER, which is provided from well –bonded phosphorus atoms [5].

Manufacturing Challenges and Opportunities for PEM Electrolysis

Hydrogen generation via electrolysis has gained much attention internationally as not only a sustainable source of fuel for the transportation, but as a carrier of energy to capture stranded renewable due to the carbon-free chemical cycle and response characteristics of the technology. The barrier to entry preventing this technology from being widely adopted is the overall cost associated with both the upfront capital expense as well as the operating cost incurred over the product life. The majority of this cost is driven by 1) low electrical efficiencies due to the high ohmic resistance of thicker membranes required by electrolysis systems to electrochemically compress generated hydrogen for storage and the overpotential associated with the water splitting oxygen evolution reaction (OER) catalysts typically used, 2) high cost of system and cell stack materials, which need to be durable for up to 100,000hrs at a potential of 2V in both reducing and oxidizing environments, and 3) the lack of a robust supply chain for high volume manufacturing to further drive down cost through economies of scale.With 95% of hydrogen currently being produced through the reformation of cheap natural gas, significant cost reductions are necessary for electrolysis to become a viable alternative to the incumbent. Commercial proton exchange membrane (PEM)-based electrolysis has reached scales of several hundred kg/day, providing a relevant pathway for industrial scale hydrogen generation with tremendous opportunity for continuing cost reduction by leveraging system and manufacturing scaling laws by leveraging advancements in PEM fuel cell materials, manufacturing, and analysis tools. Order of magnitude improvements in some of the highest cost elements are easily achievable and with more research funding being directed towards hydrogen production, the realization of these reductions are occurring at a faster rate. While many improvements in stack design and materials of construction have been identified and implemented, there are still numerous opportunities to explore that would move electrolysis towards a viable, cost-effective alternative to natural gas reformation. This talk will describe some of the areas of success, where research is still needed, and ultimately how each of these improvements translate into cost and the path to reformation parity.

Forging furnace with thermochemical waste-heat recuperation by natural gas reforming: Fuel saving and heat balance

This paper considers thermochemical recuperation (TCR) of waste-heat using natural gas reforming by steam and combustion products. Combustion products contain steam (H2O), carbon dioxide (CO2), and ballast nitrogen (N2). Because endothermic chemical reactions take place, methane steam-dry reforming creates new synthetic fuel that contains valuable combustion components: hydrogen (H2), carbon monoxide (CO), and unreformed methane (CH4). There are several advantages to performing TCR in the industrial furnaces: high energy efficiency, high regeneration rate (rate of waste-heat recovery), and low emission of greenhouse gases (CO2, NOx). As will be shown, the use of TCR is significantly increasing the efficiency of industrial furnaces – it has been observed that TCR is capable of reducing fuel consumption by nearly 25%. Additionally, increased energy efficiency has a beneficial effect on the environment as it leads to a reduction in greenhouse gas emissions.

Driving Towards Highly Selective and Coking‐Resistant Natural Gas Reforming Through a Hybrid Oxygen Carrier Design

AbstractCarbon deposition can be promoted by catalyst‐assisted C−H bond dissociation, which is one of the most concerning issues in reaction engineering. Treatment of carbon contamination inevitably generates CO2 which has a detrimental effect on the environment. Consequently, the development of efficient oxygen carriers is important to commercial viability of chemical looping processes. In this work, density functional theory (DFT) calculations were conducted and reveal that carbon deposition is a cascade reaction of accumulative C−C bond forming that deactivates LFO surface due to gradual accumulation of lattice oxygen vacancies. Guided by DFT mechanistic predictions, we tailor catalytic reactive perovskite LaFeO3 (LFO) with high oxygen carrying hematite Fe2O3 (FO) into a hybrid oxygen carrier LFO‐FO. The LFO‐FO oxygen carrier exhibits excellent carbon inhibition capability and high reactivity with syngas selectivity above 98 %. This work proposes a promising strategy toward oxygen carrier development with low cost, high reactivity, and selectivity for chemical looping technology.

A hybrid fuel cell system integrated with methanol steam reformer and methanation reactor

In this paper, a hybrid fuel cell system integrated with methanol steam reformer and methanation reactor is demonstrated. Methanol steam reformer employed in this system is to produce hydrogen-rich reformate in connection with a methanation reactor to reduce the carbon monoxide content effectively, and the reformate gas is sent into a low-temperature polymer electrolyte fuel cell for direct electric power generation. The optimum conditions (temperature, water to methanol ratio, and space velocity) for methanol steam reforming (MSR) reaction and methanation (MET) reaction are verified by experiments. A comparison between pure hydrogen, reformate surrogate, and actual reformate is performed. The results show that the power density of this hybrid system achieves 245.2 mW/cm2 while it achieves 268.8 mW/cm2 when employing pure hydrogen as the fuel. An alternative novel method to solve the problem of hydrogen storage and transportation is provided and the in-situ hydrogen production and utilizing through low-temperature fuel cell system is realized, which is helpful to accelerate the commercialization process of the fuel cell.

Customized Ni–MgO–Al2O3 catalyst for carbon dioxide reforming of coke oven gas: Optimization of preparation method and co-precipitation pH

• A Ni–MgO–Al 2 O 3 catalyst was customized for CO 2 reforming of coke oven gas. • Co-precipitation was selected as the optimum catalyst preparation method. • The co-precipitated pH was optimized as 12.0. • Complex NiO species–support interactions were key for catalytic activity. • The optimized catalyst lowered the H 2 /CO ratio of coke oven gas from 7.00–1.66. Coke oven gas can be upgraded through catalytic reforming using carbon dioxide as a soft oxidant. Herein, a customized Ni–MgO–Al 2 O 3 catalyst for the carbon dioxide reforming of coke oven gas was developed by selecting an appropriate catalyst preparation method and further optimizing the key variable of the selected method. Catalysts were prepared by various methods including co-precipitation, incipient wetness impregnation, hydrothermal, co-impregnation, and sequential impregnation. Among them, the co-precipitated catalyst showed the best performance. As the key variable, the co-precipitated pH of the precursor solution was optimized as 12. The catalysts were characterized using X-ray diffraction, Brunauer–Emmet–Teller method, H 2 –temperature-programmed reduction, H 2 –chemisorption, and thermogravimetric analysis. The interaction between a complex NiO species and the support material showed a strong relationship with the number of Ni° active sites, which also has a direct connection with the activity of the catalyst. The developed catalyst successfully lowered the high H 2 /CO ratio of coke oven gas from 7.00–1.66 through the carbon dioxide reforming reaction. Moreover, the catalytic activity was maintained over 50 h and thermodynamic equilibrium was achieved, even at a high gas hourly space velocity of 600,000 h −1 .

3D CFD Modeling and Optimization of a Cylindrical Porous Bed Reactor for Hydrogen Production using Steam Reforming of Methane

Steam Reforming of Methane, which converts natural gas into products with higher economic value in the presence of a suitable catalyst bed reformer, is the most economical method for hydrogen production in petroleum refineries. This study focuses on developing a Computational Fluid Dynamics (CFD) model of a steam methane reformer. To this purpose, a steady-state heterogeneous 3 Dimensional model that was composed of mass, species, momentum, and energy balances was developed. It compares two different geometrical porous bed reformers with different heating tube configurations for better heat transfer and reforming. Effects of heating tubes inlet temperature, the ratio of inlet CH4/H2O, and the configuration of the heating tube are studied and optimized. The results show that conversion of methane will be promoted by increasing inlet temperature of the heating tube as well as the number of heating tubes in the reformer when CH4/H2O ratio is about 0.2. In this platform, the conversion of methane is not affected by the porosity below 0.35. Also, the simulations results are shown to be in agreement with typical data reported in the literature. So, this study can be used to develop industrial natural gas reformers.

Decarbonization synergies from joint planning of electricity and hydrogen production: A Texas case study

Hydrogen (H2) shows promise as an energy carrier in contributing to emissions reductions from sectors which have been difficult to decarbonize, like industry and transportation. At the same time, flexible H2 production via electrolysis can also support cost-effective integration of high shares of variable renewable energy (VRE) in the power system. In this work, we develop a least-cost investment planning model to co-optimize investments in electricity and H2 infrastructure to serve electricity and H2 demands under various low-carbon scenarios. Applying the model to a case study of Texas in 2050, we find that H2 is produced in approximately equal amounts from electricity and natural gas under the least-cost expansion plan with a CO2 price of $30–60/tonne. An increasing CO2 price favors electrolysis, while increasing H2 demand favors H2 production from Steam Methane Reforming (SMR) of natural gas. H2 production is found to be a cost effective solution to reduce emissions in the electric power system as it provides flexibility otherwise provided by natural gas power plants and enables high shares of VRE with less battery storage. Additionally, the availability of flexible electricity demand via electrolysis makes carbon capture and storage (CCS) deployment for SMR cost-effective at lower CO2 prices ($90/tonne CO2) than for power generation ($180/tonne CO2). The total emissions attributable to H2 production is found to be dependent on the H2 demand. The marginal emissions from H2 production increase with the H2 demand for CO2 prices less than $90/tonne CO2, due to shift in supply from electrolysis to SMR. For a CO2 price of $60/tonne we estimate the production weighted-average H2 price to be between $1.30–1.66/kg across three H2 demand scenarios. These findings indicate the importance of joint planning of electricity and H2 infrastructure for cost-effective energy system decarbonization.

Process Intensification through Directly Coupled Autothermal Operation of Chemical Reactors

Summary Autothermal operation of a chemical reactor involves coupling exothermic and endothermic chemical reactions for the purpose of thermal management without resorting to external energy sinks or sources. Often this is accomplished through regenerative or recuperative heat exchange between spatially or temporally separated exothermic and endothermic reactions. However, it is also possible to directly couple these reactions simultaneously within the same reactor volume, eliminating the heat-transfer bottleneck that characterizes much of chemical manufacture. It is not widely recognized that directly coupled autothermal operation allows dramatic process intensification. This perspective defines autothermal operation and contrasts it with conventional heat transfer for thermal management of chemical processes. The intensification and cost savings that can be achieved are quantified, and the implications to modular chemical process intensification are presented. Guidelines are proposed for designing directly coupled autothermal processes. Diverse examples are presented. Several challenges to expanding the field are critically discussed.

Reaction performance of Ce-enhanced hematite oxygen carrier in chemical looping reforming of biomass pyrolyzed gas coupled with CO2 splitting

Hematite enhanced by CeO2 were investigated in chemical looping reforming (CLR) coupled with CO2 splitting to achieve high quality synthesis gas and recycle CO2 into CO. CeO2, Fe2O3 and CeFeO3 solid solution generated from integration of Fe3+ and CeO2 lattice were detected in mixed oxygen carriers as major components. Owing to the charge compensation and oxygen defects formation in lattice rearrangement, CeFeO3 solid solution contributed to promoting oxygen mobility and creating oxygen vacancies. Fe2O3 particles helped provide oxygen spillover pathway from subsurface to surface and improve lattice oxygen transfer through direct contact with the surface of CeFeO3 solid solution. CeO2 enhanced metallic interaction and catalytic oxidation reactivity. The highest gas product amount and H2/CO in CLR process increased by 43.46% and 51.31%, respectively. Also, the instantaneous CO productivity of 2.47 mmol/min/g with 86.13% CO2 conversion was realized in CO2 splitting. Reaction parameters including temperature, CeO2 content and MCO2/mOC indicated positive correlation with CO productivity. The mixed oxygen carrier maintained its reactivity and stability after 15 cycles reaction following the pathway of Ce2O3/Fe2O3/CeFeO3→Ce2O3/Fe→CeFeO3/CeO2/Fe3O4, though sintering behavior was observed in reacted sample. Fe–Ce interactions and oxygen mobility were improved by successive redox reactions, which can offset the negative effects of sintering.