Evaluation of the economic and environmental impact of combining dry reforming with steam reforming of methane

Lately, there has been considerable interest in the development of more efficient processes to generate syngas, an intermediate in the production of fuels and chemicals, including methanol, dimethyl ether, ethylene, propylene and Fischer–Tropsch fuels. Steam methane reforming (SMR) is the most widely applied method of producing syngas from natural gas. Dry reforming of methane (DRM) is a process that uses waste carbon dioxide to produce syngas from natural gas. Dry reforming alone has not yet been implemented commercially; however, a combination of steam methane reforming and dry reforming of methane (SMR + DRM) has been used in industry for several years.     

Effect of Oxygen on Methane Steam Reforming in a Sliding Discharge Reactor

Hydrogen‐rich gas can be efficiently produced in compact plasma reformers by the conversion of a variety of hydrocarbon fuels, including natural gas and gasoline. This article describes experimental and modeling progress in plasma reforming of methane using a sliding discharge reactor (SDR). Experiments have been carried out in a compact device operating at low consumed power (1–2 kW). Previous studies of methane steam reforming using a SDR at atmospheric pressure show promising results (H₂ concentration higher than 55 %). In order to study the effect of oxygen on the methane conversion and thus hydrogen production, a small amount of oxygen in the range of 7–20 % was added to the CH₄‐H₂O mixture. An unexpected result was that under our experimental conditions in the SDR oxygen did not have any influence on the methane conversion. Almost the totality of added oxygen is recovered intact. Moreover, part of the H₂ produced was transformed into water by reaction with O₂. A model describing the chemical processes based on classical thermodynamics is also proposed. The results indicate that the reactor design has to be improved in order to increase conversion and hydrogen production.     

Molecular components-based representation of petroleum fractions

Characterisation of petroleum fractions is the systematic analysis and representation of composition and properties of petroleum fractions. Characterisation methods play an important role in understanding of the physical and chemical behaviour of a petroleum fraction, its individual constituents, and are essential for modelling of refinery processes. In order to comply with the current and future product specifications for cleaner fuels, refineries are employing new processing technologies and more severe operating conditions in existing operating units. Consequently refinery process models are required to capture the chemistry of conversion processes employing characterisation of petroleum fractions at molecular level. In this paper a review of the conventional characterisation methods used for modelling of refinery processes is presented. The molecular type and homologous series (MTHS) matrix representation of petroleum fractions is discussed in detail. The previous work on MTHS matrix representation approach is limited to light petroleum fractions such as gasoline, and takes into account only hydrocarbon molecules. These shortcomings of MTHS matrix representation approach are addressed in this work through the development of a new strategy for estimation of composition and properties of petroleum fractions.     

Fuzzy optimization design of multicomponent refinery hydrogen network

Hydrogen and light hydrocarbon components are essential resources of the refinery. The optimization of the refinery hydrogen system and recovery of the light hydrocarbon components contained in the gas streams are key strategies to reduce the operating costs for sustainable development. Many research efforts have been focused on the optimization of single impurity hydrogen network, and the flowrates of the hydrogen sources and sinks are assumed to be constant. However, their flowrates vary along with the quality of crude oil and refinery processing plans. A general superstructure of multicomponent refinery hydrogen network is proposed, which considers four components, namely H₂, H₂S, CH₄ and , as well as the flowrate variations of hydrogen source and hydrogen sink. The mathematical model based on the superstructure is developed with objective functions, including the minimization of total annualized cost and the maximization of overall satisfaction of the hydrogen network. Moreover, the model considers the removal of hydrogen sulfide and the recovery of light hydrocarbon components (i.e.C₂₊, ) in the optimization. To verify the applicability of the proposed mathematical model, a simplified industrial case study with four scenarios is solved. The optimization results show that the economic benefit can be maximized by considering both the direct reuse of gas streams from high-pressure separator (HP gas stream) and from low-pressure separator (LP gas stream) and the recovery of the light hydrocarbon streams. The fuzzy optimization method can be used to guide the optimal design of the refinery hydrogen system with multi-period variable flowrates.     

Evaluation of the effects of fuel and combustion-related processes on exergetic efficiency

The fuel used in combustion applications has significant influence on irreversibility generation and hence the exergetic efficiency of the system. This work discusses a method of estimating the availability destructions and exergetic efficiencies of combustion for different classes of fuels viz. hydrogen, hydrocarbons, alcohols and biodiesel surrogates. A ranking of these fuels is presented based on their exergetic efficiencies during isobaric and isochoric combustion. It is observed that availability destruction is greater for heavier hydrocarbon fuels and oxygenated fuels with higher oxygen fraction. Though unsaturated hydrocarbon fuels are associated with lower availability destruction, they result in poor exergetic efficiency as a significant fraction of the fuel availability is lost in the products. Hydrogen and acetylene are identified as the fuels with maximum and minimum exergetic efficiencies respectively. Optimum exergetic efficiency is obtained for reactant mixtures on the leaner side of fuel-air stoichiometry. Availability destruction increases with exhaust gas recirculation (EGR) and decreases with oxygen enrichment of the supplied air. However, oxygen enrichment entails significant chemical availability losses and lowers exergetic efficiency. Preheating the reactants is found to be effective in mitigating availability destruction.     

木质纤维素基平台化合物催化转化制备液体燃料及燃料添加剂

随着不可再生的石化资源的不断消耗以及生态环境的不断恶化,可再生资源和能源的开发和利用受到越来越多的重视。木质纤维素是地球上最丰富的可再生生物质资源,蕴藏量和产量巨大,具有广阔的开发利用前景。本文在介绍国内外木质纤维素资源开发利用研究的基础上,结合当今世界生物质能领域的研发现状,分别概述了经由呋喃类化合物及乙酰丙酸等木质纤维素基平台化合物分子,制备液体燃料和燃料添加剂的最新研究进展。在总结归纳合成途径的同时,分析了现阶段面临的主要问题及可能的解决办法,以期能为木质纤维素类生物质能源化利用的研究提供有益的参考与借鉴。     

轻烃蒸汽转化制氢HYSYS软件全流程模拟

轻烃蒸汽转化制氢作为目前国内外比较成熟的制氢技术之一使用很广泛,通过HYSYS软件对榆林炼油厂20 000 m~3/h天然气蒸汽转化制氢进行全流程模拟,详细介绍了装置各工序流程模拟过程中模块的建立过程及方法,并结合现场实际参数对全流程模拟进行优化设置,将全流程模拟的原料适用范围扩展至炼厂副产的轻烃类混合物,使得此流程模拟计算在以轻烃蒸汽转化制氢工艺技术的设计过程中通用,并对使用轻烃蒸汽转化制氢工艺技术的生产装置在开工和生产阶段提供可靠的动态参考数据。     

过渡金属镍对碳氢燃料的催化结焦作用的研究

碳氢燃料在高温裂解时容易产生结焦,对工业生产和工业安全造成很大危害。本课题选用正庚烷、环己烷和苯作为模型碳氢燃料,研究模型燃料在Ni表面的结焦特征。结果表明碳氢燃料在Ni表面产生的结焦主要为无定形碳或碳纤维两种;不同碳源产生的碳纤维含量多少有所差异。在一定温度和一定时间下,以镍作为催化剂研究其结焦率的变化。通过研究结焦率的变化趋势和规律,为以后的进一步深入研究提供理论数据。     

Electricity,methane and liquid carbon dioxide production from landfill gas

Landfill gas, which has a typical composition of 40–60% methane, 40–50% carbon dioxide, and a wide range of impurities, has historically been recovered solely for its heating value. After only minor impurity removal, landfill gas has been used as medium Btu industrial fuel or to generate electricity; after significant impurity and carbon dioxide removal, landfill gas has been used as a source of pipeline quality methane. For both cases, the value of the substantial amount of contained carbon dioxide has not been realized. This has been due to the impurities which present a significant obstacle to the economic production of merchant grade carbon dioxide.This paper presents two processes¹ which make use of an oxygen fed combustion step to reduce both the quantity and variety of impurities which must be removed to meet carbon dioxide product specifications. The two processes produce carbon dioxide and electricity or carbon dioxide and pipeline quality methane, respectively. In both oxygen based coproduction processes, the combustion step is integrated into the overall process to maximize energy efficiency. The two processes are described and anticipated net liquid carbon dioxide manufacturing costs are presented.     

中国碳中和目标下CO2转化的思考与实践

提出政策引导CO₂回收、利用与封存（CCUS）发展,需重新定义二氧化碳的属性及价值,深度挖掘其资源属性,在以煤油气为一次能源、电为二次能源,向以电热为一次能源、氢为二次能源的再电气化能源革命转型中,为从有碳能源向无碳能源转变,将影响及重构所有社会活动及产业。本文通过未来低碳场景下CCUS绿色技术的思考,指出以二氧化碳氢化的三个技术链的创新开发和实践,使二氧化碳转化为合成气（CO+H₂）,从而实现高值化、资源化碳的固化和封存。文章提出：煤电、煤化工与水泥产业的二氧化碳氢化及费托合成高碳烃燃料,不仅高值化,还可用于电网调峰;沼气及非常规天然气CO₂与CH₄的干重整可生产绿氢、可再生燃料及甲醇而高值化,对于中国的乡村振兴具有特别意义,可打通村镇废弃物处理能源化与国家工业补农业的能源基金通道,将使中国乡村振兴获得资本强化新机遇;钢铁及炼化产业的低碳发展,煤气及干气的二氧化碳干重整高值利用,特别是干重整合成气生产甲醇经甲醇制烯烃（MTO）生产乙烯和丙烯及聚合物进行碳固化,将使CCUS获得新的产业链。CCUS将成为所有社会活动及工业的附属产业,成为新的公共服务产业链。     

Catalytic Partial Oxidation. Part I. Catalytic Processes to Convert Methane: Partial or Total Oxidation

The presence of large reserves of natural gas has stimulated research to utilize methane, its principal component, as an alternative energy source and to convert it to other fuels and industrially important chemicals. The reserves of natural gas in the world are estimated to be 1.4 × 10¹⁴ Nm³, while new gas fields are being discovered every year. Although this natural gas is available under pressure for piping and transport, extensive research efforts have been directed to develop gas-to-liquid (GTL) technology for the conversion of remote natural gas reserves into high-added-value liquid products, such as methanol and synthetic fuels, that can be more easily transported. A further incentive for natural gas utilization originates from environmental concerns that drive the search for cleaner energy sources. Catalytic combustion of methane offers an attractive alternative to gas-phase homogeneous combustion since it can stabilize flames at lower fuel-to-air ratios, thereby lowering flame temperatures and reducing NO_x emission. Another alternative can be found in the conversion of natural gas into hydrogen, which can be used to generate electricity in fuel cells. Fuel cells have a much higher energy efficiency compared to current combustion-based power plants. Also, hydrogen is a much cleaner fuel than hydrocarbon feedstocks since the only product from hydrogen fuel cells is water.     

Biofuels as a promising source of hydrogen for fuel cell power plants

The state of the art in biomass conversion into liquid hydrocarbon biofuels aimed at obtaining synthesis gas and hydrogen for duel elements is analyzed. The most promising liquid hydrocarbon and oxygencontaining fuels for synthesis gas production are vegetable oils, diesel fuel, and biodiesel. Mathematical models are developed for the autothermal reforming, steam reforming and pre-reforming of biodiesel into synthesis gas and for the steam reforming of pre-reforming products integrated with the membrane separation of hydrogen. The results of calculations are verified against experimental data. The solution suggested here ensures 93.5% efficiency of the membrane separation of hydrogen from the reaction mixture and a theoretical hydrogen yield of 128 mol per kilogram of biodiesel.     

轻烃回收工艺技术发展现状

利用轻烃回收将天然气中相对甲烷或乙烷更重的组分以液态形式回收,既满足了外输天然气的烃露点要求,又回收了高价值的液态烃作为燃料和化工原料,保障了安全生产且提高了经济效益。本文对各个轻烃回收方法的特点以及国外先进轻烃回收技术进行了介绍,并阐述了我国轻烃回收工艺存在的问题,在此基础上提出了提高轻烃回收率的方法,为实际生产提供参考。     

Soot formation in ethylene and propane diffusion flames

Small samples of gas have been withdrawn from the luminous regions of the diffusion flames of ethylene and propane burning on a Wolfhard Parker burner and these have been analysed by gas chromatography. In general, the parent hydrocarbon is rapidly decomposed on approaching and within the luminous region, acetylene being the major hydrocarbon product found. The concentration of acetylene falls rapidly near the interface with the oxidation zone suggesting that the main hydrocarbon oxidised in the latter is acetylene. The rates of soot collection, the uncorrected temperatures in the flames and the concentration of stable hydrocarbon species have also been measured when oxygen, hydrogen and acetylene respectively were added to the fuel stream. Sooting rates and uncorrected flame temperatures have also been measured when the ‘oxygen index’ of the ‘air’ supply was varied, and it has been found that the sooting rate for both fuels increases with an increase in ‘oxygen index,’ the rate of increase falling off, however, at higher values. Oxygen, when introduced into the fuel, leads to increased temperatures and sooting rates in the case of ethylene and to increased temperatures but decreased sooting rates in the case of propane. The sooting rates of flames of ethylene with acetylene or oxygen as additives increase linearly with the area under the acetylene concentration profile in the luminous zone (measured at a height of ～ 5 mm above the burner). This area is proportional to the amount of acetylene present in the luminous zone at this height, which corresponds roughly with the onset of luminosity. Acetylene thus appears to be the major stable species via which soot is formed in such flames. Propane flames with oxygen as additive to the fuel, however, behave differently in that although there is an increase in temperature and in the amount of acetylene in the luminous zone the sooting rate decreases. This discrepancy remains unexplained and requires further investigation.     

清洁燃料的研究与生产技术

21世纪的炼油企业将向炼油厂清洁化生产和生产更加清洁的燃料方向发展。我国炼油厂改善催化裂化汽油、柴油的质量是当务之急。简要介绍了汽油、柴油质量发展趋势和清洁燃料生产技术开发应用的原则,以及清洁汽油、柴油生产技术的新进展。     

The Catalytic Synthesis of Hydrocarbons from Carbon Monoxide and Hydrogen

The increasing demand for energy, coupled with the uncertainty and expense of crude oil imports, has renewed interest in the production of fuels and chemicals from hydrogen-deficient materials. These energy sources such as coal, residua, oil shale, and tar sands can be gasified with steam and oxygen to produce a gas containing large quantities of carbon monoxide and hydrogen. Once methane is removed from this CO/H₂ mixture it is purified to remove S poisons and then reacted over a catalyst to produce a variety of organic products. The synthesis of hydrocarbon products, with the exception of methane, is commonly referred to as the Fischer-Tropsch synthesis reaction.     

炼厂酸性气制取硫酸生产总结

介绍炼厂酸性气制硫酸装置的工艺过程。由于实供气源与设计值有较大出入,二氧化碳浓度偏高, 并且夹带烃类物质较多,使装置无法正常运行。通过对酸性气进行预处理后,一次开车成功,各项工艺指标均达到设计要求,遇酸性气流量突降时可补充适量硫磺,维持正常生产。     

Catalytic conversion of methane to more useful chemicals and fuels: a challenge for the 21st century

The very large reserves of methane, which often are found in remote regions, could serve as a feedstock for the production of chemicals and as a source of energy well into the 21st century. Although methane currently is being used in such important applications as the heating of homes and the generation of hydrogen for ammonia synthesis, its potential for the production of ethylene or liquid hydrocarbon fuels has not been fully realized. A number of strategies are being explored at levels that range from fundamental science to engineering technology. These include: (a) stream and carbon dioxide reforming or partial oxidation of methane to form carbon monoxide and hydrogen, followed by Fischer–Tropsch chemistry, (b) the direct oxidation of methane to methanol and formaldehyde, (c) oxidative coupling of methane to ethylene, and (d) direct conversion to aromatics and hydrogen in the absence of oxygen. Each alternative has its own set of limitations; however, economical separation is common to all with the most important issues being the separation of oxygen from air and the separation of hydrogen or hydrocarbons from dilute product streams. Extensive utilization of methane for the production of fuels and chemicals appears to be near, but current economic uncertainties limit the amount of research activity and the implementation of emerging technologies.     

制氢技术的发展与炼厂氢气资源

探讨了炼厂制氢技术的发展现状与趋势,分析了炼厂氢气的来源及获得廉价氢气资源的途径,指出应加强炼厂氢气资源利用的优化管理,大力开发与推广应用重质烃类原料制氢工艺。     

Biomass-to-bioenergy and biofuel supply chain optimization: Overview,key issues and challenges

This article describes the key challenges and opportunities in modeling and optimization of biomass-to-bioenergy supply chains. It reviews the major energy pathways from terrestrial and aquatic biomass to bioenergy/biofuel products as well as power and heat with an emphasis on “drop-in” liquid hydrocarbon fuels. Key components of the bioenergy supply chains are then presented, along with a comprehensive overview and classification of the existing contributions on biofuel/bioenergy supply chain optimization. This paper identifies fertile avenues for future research that focuses on multi-scale modeling and optimization, which allows the integration across spatial scales from unit operations to biorefinery processes and to biofuel value chains, as well as across temporal scales from operational level to strategic level. Perspectives on future biofuel supply chains that integrate with petroleum refinery supply chains and/or carbon capture and sequestration systems are presented. Issues on modeling of sustainability and the treatment of uncertainties in bioenergy supply chain optimization are also discussed.