Conversion Of Natural Gas Research Articles

Alkane Functionalization via Catalytic Oxychlorination: Performance as a Function of the Carbon Number

Catalytic alkane oxychlorination has recently been demonstrated as attractive for the selective conversion of natural gas into olefins, which are pivotal commodities of the chemical industry. Herein, the oxychlorination of ethane, propane, and butane over metal phosphates (Fe, Mn, and V), europium oxychloride, titanium oxide, and cerium oxide is investigated to assess the role of the carbon number on the reactivity and product distribution. Three categories of catalysts are distinguished: systems showing the highest activity in the oxychlorination of ethane CeO2, (VO)2P2O7, propane (EuOCl, FePO4, TiO2), or butane (Mn3(PO4)2). All catalysts achieve high (70–95%) selectivity toward ethylene in ethane oxychlorination, whereas they favor combustion and cracking pathways in the case of propane and particularly of butane. Furthermore, the catalytic oxidation of alkane and of HCl and alkyl chloride dehydrochlorination is assessed to rationalize the catalytic performance, revealing a linear correlation between the reactivity of the catalysts and the ability of the material to evolve chlorine, which weakens with increasing carbon number. In addition, the olefin selectivity in alkane oxychlorination is found to be driven by the rate of alkyl chloride dehydrochlorination and the propensity toward alkane cracking and combustion over the catalysts, both increasing from ethane to butane.

The role of homogeneous steam reforming of acetylene in the partial oxidation of methane to syngas in matrix type converters

The conversion of natural gas to syngas is a key and most expensive stage of modern gas chemical technologies. As a promising alternative to existing technologies, a non-catalytic matrix conversion of natural gas to syngas was proposed. However, the reaction products, in addition to CO and H2, also contain unreacted methane, CO2 and acetylene. The latter is the most problem impurity, as it is a precursor of soot and other heavy products. In this work, the kinetic analysis of changes in the composition of the products during the matrix conversion of rich methane-air mixtures up to the establishment of the thermodynamic equilibrium was carried out. Three characteristic stages of the process were identified. The first stage of fast reactions involving oxygen is completed in a very short time (∼10−2 s at 1500 K) with almost complete oxygen consumption and the formation of CO, H2, CO2, H2O and some minor products of methane pyrolysis, mainly acetylene, but at their ratio, far from equilibrium. At the second stage, slow reactions of steam reforming of the formed products significantly increase the amount of hydrogen. The ratio [CO2][H2][CO][H2O] reaches an equilibrium value, but not the concentration of individual products due to incomplete conversion of acetylene and methane. At the third and longest stage, the system reaches equilibrium, and acetylene is not among the equilibrium products. The results of kinetic modeling and experimental study of partial oxidation of methane in matrix-type reformers have shown the important role of acetylene steam conversion in the post-flame zone. This reaction leads to a substantial decrease of methane and acetylene with a simultaneous increase in the yields of hydrogen and CO.

Catalytic partial oxidation (CPOX) of natural gas and renewable hydrocarbons/oxygenated hydrocarbons—A review

Abstract Catalytic partial oxidation (CPOX) is one of the most promising technologies for converting natural gas for fuel and chemicals synthesis. CPOX has been gaining increasing attention for conversion of natural gas to ideal syngas mixtures for fuel production. The urgency and importance of this endeavour has been increasingly recognized in the last few years due to the exploration of shale gas and flare gas. However, the information regarding the progress of industrial implementation of this technology is scarce. This review presents recent advances of CPOX techniques from bench to pilot scale and a comparison of its energy efficiency, carbon conversion efficiency, and operating costs with parallel technologies including steam reforming (SMR), autothermal reforming (ATR), and partial oxidation (POX). The potential applications and perspective of CPOX for long chain hydrocarbon and renewable hydrocarbon/oxygenated hydrocarbons conversion to new platform chemical and materials is also discussed.

Steering the ‘C-Day’: Insights from the rapid, planned transition of the UK's natural gas conversion programme

The article studies the steering strategies pursued during a major sociotechnical transition in the then state-owned British gas industry. We focus on the ten-year (1967–1977) national project to convert 35 million appliances to run on natural gas instead of manufactured gas. The article : a. addresses the issue of steering in the multi-faceted, complex process of conversion and identifies the context of and challenges faced by the natural gas conversion programme in the 1960s and how actors responded and coordinated action; b. Identifies modes of steering followed by key actors and institutions of the period; c. Identifies essential precursors for this successful steering, including: the recognition of the challenges the industry faced in the pre-transition years; an openness to experimentation, R&D and organizational and technical change; and harmonious relations with government. We argue that the steering approach needs to combine an emphasis on planning and institutional and regulatory innovation with aspects of the mundane governance approach. Our analysis shows, with reference to the UK’s low-carbon gas transition, that while rapid, planned transitions are achievable, they may require complex, demanding forms of steering and governance that may prove hard to achieve in today’s socioeconomic and political conditions.

Operation of a 50-kWth chemical looping combustion test facility under autothermal conditions

The United States Department of Energy is developing transformational fossil fuel combustion technologies that result in more efficient power cycles and/or substantial reductions in GHG emissions. Chemical Looping Combustion (CLC) has the potential to achieve a lower cost of electricity than a supercritical pulverized coal power plant with an amine absorption system. Although the concept and research on chemical looping has a long history, CLC has numerous technical issues that must be addressed prior to a commercial debut. This effort is directed toward the following major issues for CLC: (1) demonstrating continuous solids handling, operability, and reactor performance at autothermal conditions and (2) preliminary assessments of oxygen carrier attrition and relative material make-up costs. These are critical issues that should be addressed under realistic conditions prior to directing resources toward larger scale demonstrations. This paper will also describe NETL’s small 50-kWth natural gas circulating CLC test facility located in Morgantown, WV. Despite its small size, this experimental test unit has operated at autothermal conditions for 11 h using a copper-iron-alumina oxygen carrier developed at NETL. This paper will describe the test facility and operating experiences using NETL’s “Gen 2.0” oxygen carrier material. Natural gas conversion to CO2 ranged from 70 to 90% over approximately 75 oxidation-reduction cycles during the autothermal operating period. Estimates for the process specific attrition rate during autothermal operation are also presented. Finally, estimates for the oxygen carrier makeup cost, specific to the NETL process configuration, are several orders of magnitude greater than the NETL target. Future work should focus on reducing the oxygen carrier material cost and improving the attrition resistance of the oxygen carrier material under autothermal test conditions.

Materials science in the field of heat-resistant austenitic alloys

Centrifugally cast pipes from heat-resistant steels and alloys are widely used in many branches of engineering. These are radiation pipes in thermal furnaces with a protective atmosphere, bottom rollers in continuous thermal and heating furnaces of metallurgical plants, rollers in continuous annealing units, etc.The question of the possibility of increasing the operating parameters of the process of high-temperature conversion of natural gas in ammonia and methanol units is very important, because increasing the temperature and pressure not only improves the performance of the plants, but also reduces the cost of the product and allows obtaining higher purity hydrogen. In connection with the above, specialists are making efforts to improve the compositions used in steels of the type H25N35C2 by means of their additional doping.

Reversible Nature of Coke Formation on Mo/ZSM-5 Methane Dehydroaromatization Catalysts.

Non‐oxidative dehydroaromatization of methane over Mo/ZSM‐5 zeolite catalysts is a promising reaction for the direct conversion of abundant natural gas into liquid aromatics. Rapid coking deactivation hinders the practical implementation of this technology. Herein, we show that catalyst productivity can be improved by nearly an order of magnitude by raising the reaction pressure to 15 bar. The beneficial effect of pressure was found for different Mo/ZSM‐5 catalysts and a wide range of reaction temperatures and space velocities. High‐pressure operando X‐ray absorption spectroscopy demonstrated that the structure of the active Mo‐phase was not affected by operation at elevated pressure. Isotope labeling experiments, supported by mass‐spectrometry and 13C nuclear magnetic resonance spectroscopy, indicated the reversible nature of coke formation. The improved performance can be attributed to faster coke hydrogenation at increased pressure, overall resulting in a lower coke selectivity and better utilization of the zeolite micropore space.

Reversible Nature of Coke Formation on Mo/ZSM‐5 Methane Dehydroaromatization Catalysts

AbstractNon‐oxidative dehydroaromatization of methane over Mo/ZSM‐5 zeolite catalysts is a promising reaction for the direct conversion of abundant natural gas into liquid aromatics. Rapid coking deactivation hinders the practical implementation of this technology. Herein, we show that catalyst productivity can be improved by nearly an order of magnitude by raising the reaction pressure to 15 bar. The beneficial effect of pressure was found for different Mo/ZSM‐5 catalysts and a wide range of reaction temperatures and space velocities. High‐pressure operando X‐ray absorption spectroscopy demonstrated that the structure of the active Mo‐phase was not affected by operation at elevated pressure. Isotope labeling experiments, supported by mass‐spectrometry and 13C nuclear magnetic resonance spectroscopy, indicated the reversible nature of coke formation. The improved performance can be attributed to faster coke hydrogenation at increased pressure, overall resulting in a lower coke selectivity and better utilization of the zeolite micropore space.

The critical contribution of chemical engineering to a pathway to sustainability

The vision of a pathway to a sustainable society is based on the three-pillar conception of sustainability (economic, environmental, and social) that is expected to result in a significant improvement in the reliability, security, and affordability of energy, materials, water, and food. This pathway should include launching a multidisciplinary and least-cost strategy to move from today’s carbon-based economy toward a sustainable economy and, at the same time, to provide the needed energy, water, food, and materials for present and future generations. It is imperative that chemical engineers do not relinquish their leadership role in research and development as global energy systems continue to evolve in a historical cycle from primary reliance on wood to coal and oil, to current reliance on natural gas as a transitional fuel in contributing to a pathway to sustainable global energy systems. Although multidisciplinary research and development is needed to move forward on a pathway to sustainability, in this paper, specific areas of research and development are discussed in which chemical engineers should assume a leadership role or become major contributors in this critical initiative. These areas include, but are not limited to: carbon capture, utilization, and sequestration; process intensification; material recycling; water management and desalination; biofuel; natural gas production and conversion; energy storage; and renewable energy, including concentrated solar energy use in chemical, pharmaceutical, and biological processes, and advanced materials for photovoltaics.

Enhanced Procurement and Production Strategies for Chemical Plants: Utilizing Real-Time Financial Data and Advanced Algorithms

This paper presents an implementation of an automated algorithm powered by market and physical data to improve procurement and production of a chemical plant with the goal of improving the overall economics on the entity. Herein, the algorithm is applied to two scenarios that serve as case studies: conversion of natural gas to methanol and crude palm oil to biodiesel. The program anticipates opportunities to increase profit or avoid loss by analyzing the futures market prices for both reagents and the products while considering cost of storage and conversion derived from physical simulations of the chemical process. Analysis conducted on June 11, 2018, in the biodiesel scenario shows that up to 219.28 USD per tonne of biodiesel can be earned by buying contracts for delivery of crude palm oil in July 2018 and selling contracts for delivery of biodiesel in August 2018 which equates to a margin 11.6% higher than in case of the direct trade. Moreover, it is shown that losses of up to 11.3% can be avoided, and...

Methane dehydroaromatization over molybdenum supported on sulfated zirconia catalysts

The shale gas revolution has strongly impacted the world by providing a significant incentive for research in natural gas conversion. Natural gas is becoming an important feedstock for the production of valuable chemicals. Dehydroaromatization (DHA) is an important non-oxidative conversion route for methane conversion, and Mo doped on the H-ZSM-5 or H-MCM-22 have been well-studied for this reaction. In these catalysts, Mo sites activate CH4 to form dimeric species that are subsequently oligomerized on the strong Brønsted acid sites. In the present study, Mo is doped on solid sulfated zirconia (SZ) to create a catalyst similar to Mo/H-ZSM-5, but with a different solid acid. Despite the logic of using SZ as the acid, we are aware of no systematic study of Mo/SZ catalysts for this reaction. These catalysts were characterized using Raman, XPS, DRIFTS, SEM-EDS, HRTEM, XRD, XANES and other temperature programmed techniques. Raman spectra confirmed the formation of Mo = O and OMoO bonds on the surface of SZ support. DRIFTS confirmed that there was little difference in acid sites when Mo was doped on SZ, except at higher Mo loadings. XPS, XANES, and HRTEM analysis showed that MoO3 is converted to MoOxCy and is further converted to Mo2C as the reaction progresses. Further, these catalysts were evaluated for methane DHA reaction. All of these catalysts showed methane conversions of 5–20 % at temperatures of 600–700 °C. In each case, the catalysts deactivated steadily, attributable to strong coking on the surface, as confirmed with TPO. A comparison with literature showed that Mo/SZ has comparable activity to Mo/H-ZSM-5 at around 650 °C–675 °C temperature range. Further, Mo/SZ was more selective towards heavier aromatics such as naphthalene and coke as compared to Mo/H-ZSM-5 at 700 °C, which is more selective towards benzene.

Matrix conversion of natural gas to syngas: The main parameters of the process and possible applications

This study demonstrates the possibility and good practical prospects of a principally new type of noncatalytic matrix conversion of natural gas and associated petroleum gas to syngas. Matrix reformers can operate on various types of oxidizers, such as air, enriched air, and oxygen, thereby producing syngas with the desired nitrogen content, including nitrogen-free syngas for petrochemical applications. The optimal value of oxygen excess coefficient, α = 0.34 − 0.36, provides a high conversion of reagents and a high yield of syngas in such a simple noncatalytic process. Addition of steam stabilizes the matrix temperature and decreases the yield of acetylene, thereby making the process more stable.

Solar Energy Assisted Membrane Reactor for Hydrogen Production

Pd-based membrane reactors are strongly recognized as an effective way to boost H2 yield and natural gas (NG) conversion at low temperatures, compared to conventional steam reforming plants for hydrogen production, thereby representing a potential solution to reduce the energy penalty of such a process, while keeping the lower CO2 emissions. On the other hand, the exploitation of solar energy coupled with a membrane steam reformer can further reduce the environmental impact of these systems. On this basis, the paper deals with the design activities and experimentation carried out at a pilot level in an integrated prototype where structured catalysts and Pd-based membranes are arranged together and thermally supported by solar-heated molten salts for steam reforming reaction

A Versatile Converter of Liquid Hydrocarbons for the Production of Reducing and Carbonization Atmospheres

Abstract We herein report the results of our investigation into the modes of catalytic partial oxidation (CPOX) of liquid fuels and air mixtures to yield endothermic (endo) gas on a pilot-scale installation containing ~ 0.45 cm3 catalytic bed. This endothermic gas serves as a protective atmosphere in thermochemical steel treatment processes. Seven liquid hydrocarbons (LHs) are investigated, namely isooctane, 91 RON (research octane number) and 95 RON gasoline, diesel, kerosene, jet fuel, and naphtha. All experiments are performed using our previously developed reactor, where the reactions of natural gas/air mixtures were previously studied. In the present study, we report that the LH conversion products reached an equilibrium state similar to that of methane and natural gas conversion with an atomic C/O ratio of ~ 1.0 in the mixture. Furthermore, working regimes between 850 and 950 °C are examined as typical reaction conditions for industrial endo gas generators, and in all cases, the required gas quality is achieved. However, we found that gasoline and diesel are the most suitable LH feedstock for endo gas generation.

High purity syngas and hydrogen coproduction using copper-iron oxygen carriers in chemical looping reforming process

Chemical looping reforming presents an attractive alternative to the conventional processes for chemicals and energy production from carbonaceous fuels with significant reduction in carbon emissions and high exergy efficiency. Production of syngas and hydrogen is important because the former is a critical building block for valuable chemicals and latter is a source of clean energy. The use of copper-iron (Cu-Fe) oxygen carriers for coproducing syngas and hydrogen in a chemical looping reforming process is studied via experiments and process simulations. Three different compositions of Cu and Fe oxides are examined for their properties concerning the reactivity towards fuel and the selectivity towards syngas. The feasibility of using a co-current moving bed reactor configuration for syngas production is probed experimentally in a fixed bed reactor by placing the fully oxidized and reduced oxygen carrier in series. The methane conversion and dry syngas purity as high as 99.5% and 97.5%, respectively, are observed for copper oxide (20 wt%) - iron oxide (60 wt%) - aluminium oxide (20 wt%) oxygen carrier in a simulated co-current moving bed reactor. Key performance parameters including effective thermal efficiency for 5 different configurations of the chemical looping reforming process from ASPEN Plus simulation software are compared against the baseline case of the auto-thermal reforming process. Apart from an improvement in the natural gas conversion and syngas purity in the chemical looping reforming process, the net hydrogen production is increased by 28% and effective thermal efficiency is increased by 10% over that of the auto-thermal reforming process.

Electrophysical Setup for the Conversion of Natural Gas at Atmospheric Pressure

The conversion of hydrocarbons during the treatment of a methane–ethane mixture with a barrier discharge in an electrophysical setup was experimentally studied. The theoretical estimation of plasmakinetic processes occurring in a discharge was performed for the developed plasmachemical reactor using the ZDPlasKin algorithm. Experimental results were in agreement with theoretical estimates.

Combined production of ammonia and methanol as the way to deal with the greenhouse gas

Technological processes in the energy sector and at the enterprises of nitrogen fertilizers, accompanied by the release of large amounts of greenhouse gas - carbon dioxide into the atmosphere are considered. Optimal options for its utilization are proposed, based on the bicarbonate conversion of natural gas to produce methanol and gas-cyclic CO2 injection into oil producing wells in order to increase oil recovery.

Thermodynamic analysis of an integrated gas turbine power plant utilizing cold exergy of LNG

The main concerns in energy from petroleum-based fuels are the scarcity, cost, and pollution the fuels. Now, natural gas is considered as a better alternative. The process of converting natural gas into liquefied natural gas (LNG) is highly energy intensive and consumes about 10–15% of the total energy spent on natural gas production. Novel methods for regasification of LNG (converting back to NG) exist and are being used in various applications; mainly in power generation and refrigeration. One such method in power generation, the cold associated with LNG (cold exergy) can be utilized efficiently for improving the performance of power plants based on the Brayton cycle by precooling the working fluid. The study investigated such a possibility of precooling the inlet working fluid and to bring out the various factors influencing the overall efficiency of the power plant and regasification of LNG. Exergy analysis is the tool used for this study. The combined power plant is modeled using Aspen Hysys process simulation tool, and the results show that there is 35-135% improvement in the exergy efficiency of the power plant. This study also intends to find a suitable working fluid based on the objective functions such as exergy efficiency of the power plant and a regasification parameter (mass flow ratio). The gas turbine cycle gives maximum exergy efficiency when air is used as working fluid and Helium is the best working fluid candidate where regasification is the prime objective. Helium can gasify LNG about ten times more than other three working fluids

Hydrogen Production by Steam Reforming of Natural Gas Over Vanadium-Nickel-Alumina Catalysts.

A series of vanadium-nickel-alumina (xVNA) catalysts were prepared by a single-step sol-gel method with a variation of vanadium content (x, wt%) for use in the hydrogen production by steam reforming of natural gas. The effect of vanadium content on the physicochemical properties and catalytic activities of xVNA catalysts in the steam reforming of natural gas was investigated. It was found that natural gas conversion and hydrogen yield showed volcano-shaped trends with respect to vanadium content. It was also revealed that natural gas conversion and hydrogen yield increased with decreasing nickel crystallite size.

Effect of reduction on Co catalyst active phase highlighted by an original approach coupling ASAXS and electron tomography

Diversification of liquid fuel sources for transportation plays a key role in the energetic transition. High quality and clean diesels can be produced by Fischer-Tropsch synthesis, which interest is renewed in as much it can be performed from syngas (CO + H2) produced by conversion of natural gas or gasification of lignocellulosic biomass, leading, in this latter case, to fuels from renewable resource. Catalytic performance (activity and selectivity) of cobalt-based catalysts are related to the physico-chemical characteristics of the cobalt nanoparticles. The present study proposes a new approach to obtain a detailed and exhaustive description of the cobalt active phase in FT catalysts. We combined Anomalous Small X ray Scattering (ASAXS) and electron tomography, giving complementary insights on the microstructure and size distribution of both cobalt nanoparticles and aggregates. This approach, carried out on a cobalt/alumina-silica catalysts studied first at the oxide state and then at the reduced state, allowed to highlight the mechanisms involved at the nanoscale during the reduction step. Reduction impact is significant on aggregates morphology, causing their fragmentation and increasing their accessibility. As a perspective, a better knowledge of cobalt aggregates morphology will help to understand their impact on the catalyst performance.