天然气制氢技术及经济性分析

氢能是当前最有前景的清洁能源之一,天然气制氢是目前全球最主要的制氢方式,重点介绍和分析了主要制氢技术路线天然气水蒸气转化制氢,该工艺主要包括水蒸汽重整转化、合成气变换及变压吸附三个单元;同时还介绍了非水蒸气转化制氢路线,包括甲烷部分氧化法制氢、天然气催化裂解制氢及CH₄/CO₂干重整制氢。比较了几种制氢技术的经济性。目前,虽然煤制氢的成本优于天然气制氢,但随着天然气开采技术的进步,未来天然气制氢有可能成为国内最主要的制氢技术路线。      

天然气氢炭联产工艺研究进展

在“碳达峰和碳中和”背景下,国家对天然气的综合利用和清洁生产有更高要求。对天然气制炭工艺以及制氢工艺进行了阐述,指出传统生产工艺的弊端,即碳氢元素两者未能同时得到有效利用,造成潜在资源的浪费。而甲烷热裂解技术可以同时实现氢炭联产,且不直接排放CO₂,具有显著的经济以及环境效益,因而受到广泛关注。综述了4种不同的天然气氢炭联产技术,从技术原理、工艺流程、催化体系、尾气排放等方面进行论述,并对4种技术的优缺点进行了对比。其中,熔融法和等离子体法在天然气氢炭联产过程中不产生温室气体,是较为理想的氢炭联产技术。此外,提出了天然气氢炭联产未来技术发展和攻关方向的建议。      

生物油水溶性组分重整制氢研究进展及关键问题分析

 随着全球化石燃料枯竭和气候变暖加剧,H₂作为一种洁净能源载体备受关注。生物质热解工艺制取的生物油具有易于储运、可再生、CO₂零排放等特征,可作为一种潜在的制氢原料。笔者对生物油水溶性组分提质制取 H₂的水蒸气重整、自热氧化重整、水相催化重整3种制氢技术进行了综述,分析了各工艺的反应机理、研究现状及关键科学问题,指出了各种方法的特点、优势与不足及改进方法。针对生物油利用过程中的瓶颈问题,简要展望了生物油水溶性组分提质制取 H₂的研究重点。     

FCC再生低碳排放供氢工艺探索研究

 再生器是催化裂化（FCC）工艺中二氧化碳（CO₂）排放的主要单元。随着掺渣比的增加,再生单元热量过剩,CO₂排放随之增加。利用部分焦炭生产合成气或 H2,不仅可以供氢,而且能够收集 CO₂、硫等有害物,减少排放。实验数据显示,在700℃左右气化待生剂上的焦炭,气体产物有效组分（CO+H₂）体积分数大于55%。对于加工2.0 Mt/a 原料油的重油催化裂化装置（RFCCU）来说,如果焦炭产率为10%,气化反应65%的焦炭,则具有生产9.8 kt/a H₂的潜力,如果分离系统回收CO₂,则可减少碳排放约60%。     

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面对由温室效应导致的日益严重的全球气候灾难，二氧化碳减排已经刻不容缓。氢气作为理想的清洁能源，在应用环节可以实现零排放。然而要实现全生命周期的CO₂减排，必须考虑在用化石燃料制氢环节中回收并处理CO₂。考察了几种目前常用的大规模制氢方法——天然气蒸汽重整(SMR)、自热重整(ATR)、部分氧化和煤气化制氢的工艺流程，用Aspen PlusTM对这几种制氢工艺流程进行模拟仿真，并进行了能量和经济性分析。指出对中国减排CO₂而言, 煤气化激冷-高温净化方案是最经济可行的,并可进一步发展为以煤气化为核心的多联产系统,对我国的可持续发展具有重要意义。     

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面对由温室效应导致的日益严重的全球气候灾难，二氧化碳减排已经刻不容缓。氢气作为理想的清洁能源，在应用环节可以实现零排放。然而要实现全生命周期的CO₂减排，必须考虑在用化石燃料制氢环节中回收并处理CO₂。考察了几种目前常用的大规模制氢方法——天然气蒸汽重整(SMR)、自热重整(ATR)、部分氧化和煤气化制氢的工艺流程，用Aspen PlusTM对这几种制氢工艺流程进行模拟仿真，并进行了能量和经济性分析。指出对中国减排CO₂而言, 煤气化激冷-高温净化方案是最经济可行的,并可进一步发展为以煤气化为核心的多联产系统,对我国的可持续发展具有重要意义。     

CO2利用在有机合成中的研究进展

大气中CO₂含量不断增加对环境和社会的影响是目前全球面临的最重大挑战之一。作为减缓和适应气候变化的行之有效的手段,碳捕获、利用和封存已引起越来越多的关注。其中,CO₂利用,即直接使用CO₂或将其转化为更有价值的产品,已成为减少CO₂排放广泛战略中的一个极其重要的组成部分,这一挑战的实现需要技术和政策变革的支撑。总结和讨论了近20年来国内外利用催化、合成技术,将CO₂转化为高附加值特定化学品(如甲酸、甲醇、聚合物等)的工艺研究进展和存在的相关挑战,并从原子高效率利用和工业角度,提出一些以CO₂为合成原料的具有一定工业应用前景的有机合成方法,如基于CO₂的聚醚醇碳酸酯和聚碳酸酯的合成,并指出实现这一工业应用面临的难点和挑战。     

川东北地区富含H2S天然气烃类与CO2碳同位素特征及其成因

虽然近年来对川东北地区富含H₂S天然气的地球化学特征、成因及来源开展了广泛研究并积累了丰富的地质、地球化学资料,但由于该地区特殊的地质环境和复杂的天然气形成演化条件,天然气成因与来源问题一直备受关注并存有争议。川东北地区天然气中H₂S含量与烃类组分组成、甲烷、乙烷和CO₂碳同位素组成之间的关系表明,飞仙关组—长兴组富含H₂S的天然气主要是原油在硫酸盐催化下裂解的产物,可能主要来源于下志留统烃源岩;高含H₂S天然气中富集重碳同位素CO₂的生成,与天然气中H₂S含量的降低有关,是H₂S溶蚀储层碳酸盐岩的结果。     

自愈合材料在油气钻采领域中的研究现状

为了提高对应用CO₂开发页岩油藏机理和规律的认识,系统论述了CO₂在页岩油藏中的提高采收率机理,包括CO₂对页岩油的快速增能、降黏、解堵、萃取和储层改造等机理;详述了CO₂开发页岩油的技术特点和储层动用特征。随着CO₂在页岩油藏注入量的增加,CO₂与页岩油混合的p-T相图两相包络线区域变大,临界点上移,增加了页岩油藏的溶解气驱能量。由于页岩油藏中裂缝充分发育,CO₂驱表现出严重的气窜,而CO₂吞吐更适用于开发页岩油藏。吞吐提高页岩油采收率的本质是CO₂向页岩基质中的强扩散、传质和补能作用,且有裂缝存在的油藏进行CO₂混相吞吐效果好于无裂缝油藏的非混相吞吐。CO₂开发页岩油时主要动用页岩油藏内0.008 μm以上孔隙内的油,且大孔隙内的油先被动用。提高CO₂对页岩储层的动用孔隙下限的方法为提高注入压力或增加有效吞吐周期,从而增强CO₂在油藏中的扩散和传质性。     

基于CO2特性的无水加砂压裂技术研究与应用

吉林油田致密油资源潜力大,储层物性差,常规水力压裂改造技术易造成储层污染、能量补充不及时,油井产量递减快。CO₂无水压裂技术具有增加地层能量、降低储层伤害、原油混相等技术优势。基于液态CO₂压裂液体系的黏度、携砂性及滤失特征方面的研究,开展了CO₂无水压裂技术加砂试验。通过优选增稠剂Ⅱ型压裂液提高CO₂的黏度,采用段塞与连续加砂相结合的加砂方式、优化前置液比例,完善加砂工艺,提高加砂规模,压裂液体系黏度增加15～45倍,效果明显好于增稠剂Ⅰ型。CO₂无水加砂压裂技术实施的10口井压后日产油是常规重复压裂的2倍以上,折算单井节约水资源1 512 m³。      

Direct conversion of an agricultural solid waste to hydrocarbon gases via the pyrolysis technique

The increased awareness toward the global warming and the environmental pollution problems has stimulated the utilization of the alternative energy sources since they can positively take part in minimizing such problems. Among these sources, biomass based solid wastes is counted as one of the most promising in the field of energy production. Thus, the current research work focuses on the conversion of rice straw (a biomass-based solid waste) into hydrocarbon gases in general and methane (main constituent of natural gas) in particular. The reduction of the operational temperature and the elevated rate of solid-to-gas conversion are newly presented approaches in this research. Specifically, the used operating temperature, in this study, had been 250?°C while the well-known temperature range for slow pyrolysis is 380–550?°C. Another approach is represented in this work via the orientation of the obtained biogas to become mainly hydrocarbon gases instead of CO, CO₂ and CH₄ mixture, as the common for such pyrolysis processes. The attained high rate of solid-to-gas conversion (80%) while at low temperature is also a new approach of this study since such high rate is just possible in the flash pyrolysis (750–900?°C). The increased conversion rate was achieved via reducing the particles size of the used solid-biomass to a nano-sized range.     

Gas–liquid membrane contactors for carbon dioxide capture from gaseous streams

Membrane technology is characterized by high efficiency, compatibility and flexibility of various membrane processes in integrated systems, low power consumption, high stability and environmental safety of processes, comparative ease and simplicity of controlling and scaling-up, as well as a unique functional flexibility of the membrane processes. This is why the membrane technology is considered as a promising way to reduce anthropogenic emissions of carbon dioxide into the atmosphere. Gas–liquid membrane contactors are a prime example of high-performance hybrid processes using membrane technologies. Integrating several separation methods in one device (membrane contactor) makes it possible to retain benefits of membrane technology, such as small size and flexibility, complementing them with high separation selectivity typical of CO₂ absorption. This review presents the basic principles of operation and design of membrane contactors, and a wide range of materials, membranes, and liquid absorbents for membrane CO₂ absorption/stripping are considered. Particular attention has been paid to current studies on CO₂ removal from thermal power plant flue gas, natural gas, biogas, and syngas. The examples of pilot-scale and semi-commercial implementation of CO₂ absorption/stripping in membrane contactors have been given.     

Post-combustion of mazut with CO2 capture using aspen hysys

There is a wide range of resources for CO₂ emissions. The net amount of CO₂ emissions in the cement industry due to the consumption of fossil fuels and the chemical processes of cement production under heating raw materials is reported to be in the range of 15–25%; this industry, among all the industries and after the power plants and refineries, is the largest CO₂ gas producer throughout the world. Using CO₂ capture and storage (CCS), it can reduce greenhouse gas emissions in a short time. In this study, the technical feasibility study of recycling CO₂ in Abyek Cement Company, with a cement production capacity of about 12,500 tons per day in two production lines, has been studied as one of the largest cement industries throughout the world. Fuel oil (Mazut) is used as the primary fuel for furnaces in this industry. Affected by combustion, the emissions emitted from the five-stage preheater contain 5/24% vol% of CO₂, 7.6% H₂O, 4.8% vol% of O₂, and 63.1% N₂.     

CO2捕集技术的研究现状与发展趋势

目的在全球节能减排的大背景以及我国“碳达峰、碳中和”的双碳战略目标指导下,有针对性地研究适用于不同工况的CO₂捕集技术成为极其重要的研究趋势。 方法结合碳捕集领域最新发展动态,针对燃烧过程中CO₂的排放,对比了吸收法、吸附法、深冷分离、膜吸收法、超重力法等技术的优缺点以及应用动态,分析总结了CO₂捕集技术的发展趋势。 结果阐明了几种CO₂燃烧后捕集技术的技术特点。明晰了当前吸收法中吸收剂的选择是核心,反应器与操作条件的优化是重点。对于吸附法,面向大规模工业应用,开发选择性高、吸附容量高、解吸能力强、价格便宜的吸附剂是关键。而对于膜技术,其特点是操作简便、灵活,但提高膜的性能依然是需要持续进行的研究。总体而言,阐明了几种捕集技术的特点、应用潜力和研究方向。 结论尽管当前已经有较多CO₂吸收与分离技术得到广泛的研究与应用,但在具体应用中仍存在诸多问题,针对CO₂吸收与分离的新材料、新溶剂的研究仍是碳捕集领域研究的前沿与热点课题。从碳捕集技术层面出发,今后的发展趋势很可能是两种或两种以上技术串联使用,以满足更多工况条件下的脱碳需求。      

CO2 sequestration through enhanced oil recovery in a mature oil field

Recent advances in enhanced oil recovery (EOR) technology create new opportunities for CO₂ sequestration. This paper proposes a technical–economic model for underground storage of CO₂ emitted by a fertilizer industry in the Northeast of Brazil, in a hypothetical mature oil reservoir through EOR operation. Simulations based on mass, energy and entropy balances, as well as economic analysis, were assessed for the process of CO₂ sequestration combined with EOR. This model takes into account the energy requirements for the whole CO₂ sequestration process, as well as the emissions inherent to the process. Additionally, a breakdown cost methodology is proposed to estimate the main financial determinants of the integrated EOR with CO₂ sequestration (costs of CO₂ purchase, compression, transportation and storage). Project evaluation is derived from a cash flow model, regarding reservoir production profile, price and costs, capital expenditures (CAPEX), operating expenditures (OPEX), carbon credits, depreciation time, fiscal assumptions etc. A sensitivity analysis study is carried out to identify the most critical variables. Project feasibility, as expected, is found to be very sensitive to oil price, oil production, and CAPEX. Moreover, there is the contribution from the mitigation of the greenhouse gas (GHG) by storing a significant amount of CO₂ in the reservoir where it can remain for thousands of years.     

Simulation analysis of steam gasification of petroleum coke with CaO

Abstract

The work deals with the effect of calcium oxide adsorption on the production of hydrogen and methane in steam gasification of petroleum coke using Aspen Plus process simulator. The prediction accuracy of the proposed model is verified by comparing with the existing experimental results. The effects of water vapor flux, the mass ratio of calcium oxide to petroleum coke, pressure, temperature on hydrogen or methane gasification from petroleum coke steam are studied. The production of hydrogen from petroleum coke gasification requires a low temperature and low pressure environment, while increasing the flow of water vapor is beneficial to the production of hydrogen. Maximum H₂ volume fraction of 87.3% is obtained at a temperature of 600?°C, a pressure of 0.1?MPa, the mass of steam to petroleum coke is 1, and the mass of CaO to petroleum coke is 3. The H₂ and CO₂ volume fractions are found to be increased and decreased by 20% and 27.8% respectively, when compared with the corresponding non-CaO case. The production of methane from petroleum coke gasification requires a low temperature and high pressure environment, while decreasing the flow of water vapor is beneficial to the production of methane. Maximum CH₄ volume fraction of 63% is obtained at a temperature of 600?°C, a pressure of 1?MPa, the mass of steam to petroleum coke is 1, and the mass of CaO to petroleum coke is 1. The CH₄ and CO₂ volume fractions are found to be increased and decreased by 14.4% and 21% respectively, when compared with the corresponding non-CaO case.     

The catalytic effect of manganese carbonate on kerogen pyrolysis in the absence and presence of water

To investigate the effect of Mn ore on the chemical components and isotopic compositions of gas products during kerogen pyrolysis in the absence or presence of water, a series of pyrolysis experiments on Type-I kerogen with manganese carbonate and/or water were conducted in closed gold capsules at 325–600?°C for 72?h with 300?bar. The heavy hydrocarbon gas yields increased significantly over 450?°C due to the participation of manganese. As for isotopic compositions, the manganese catalysis caused a decrease in the ¹³C_CH4 and an increase in the ¹³C_C2H6 over 475?°C; the δD values of methane generated during anhydrous pyrolysis with manganese carbonate are much lower than those produced by the pyrolysis of kerogen alone. Furthermore, the δD values are the most negative during hydrous pyrolysis with manganese ore. In addition to the thermal decomposition of manganese carbonate to form carbon dioxide, water provides sources of hydrogen and oxygen to form H₂ and CO₂. Manganese carbonate inhibits the association of sulfur-free radicals to hydrogen to form H₂S. The i-C₄/n-C₄ ratio for gas products was evidently higher due to the existence of manganese and water, they can enhance the carbocation mechanism.     

煤基质收缩和膨胀对甲烷开采和二氧化碳存储的影响

应用耦合的煤层气数值模型,模拟和对比了3种不同的煤基质收缩和膨胀模型模拟的渗透率、CH₄产量、CH₄含量分布、CO₂注入量和CO₂存储量。在无CO₂注入情况下,考虑吸附/解吸附作用的煤基质收缩/膨胀模型最大的渗透率为初始渗透率的6倍,而只考虑压力作用的煤基质收缩/膨胀模型渗透率下降2%,CH₄累积产量前者是后者的1.3倍;在CO₂注入情况下,考虑吸附/解吸附作用的模型最大的渗透率为原来的1.25倍,最小为原来的0.17倍,而只考虑压力作用的煤基质收缩/膨胀模型渗透率下降1.6%,CH₄累积产量前者是后者的1.5倍,而CO₂的注入速度和存储量后者分别是前者的14倍和3.85倍。结果表明：煤基质收缩/膨胀对CH₄开采和CO₂都有影响,吸附/解吸附导致的基质收缩/膨胀起主要作用。