中国发展煤炭清洁转化制甲醇是替代石油能源的最佳选择

我国年产20×108t煤炭相当10×108t石油,若采用粉煤气化配入水电解氢合成甲醇液体燃料,可使碳元素达99%的利用率;煤中硫化物全部回收成硫磺且免去巨额CO2排放。甲醇合成弛放气中含N2又可用于合成氨加工成尿素。甲醇油除作发动机燃料外,还可加工转化成乙烯、丙烯替代短缺的石油原料。从元素的物料、热量平衡与化学反应分析得出,煤炭纯氧气化同水电解制氢和氧,替代合成气的CO变换成H2和CO2,免去脱除与排放CO2,氧作煤气化用氧替代空分;发动机用甲醇油催化成合成气,可提高发动机的压缩比,使低热值的甲醇油成为同等于汽、柴油作功当量的甲醇汽油。1.3t煤可产1t甲醇,相当产1t石油炼制的成品油,达到节约资源、环境友好循环经济的目的。     

煤制油与煤气化制甲醇技术的比较与选择

煤炭液化制油技术投资大、煤耗高、耗水多、污染严重,以目前的技术水平,生产1t油往往需要4～5t煤,折算其热能利用率为50%,若按南非的煤耗（6t）计,其热能利用率仅为33.3%。改用煤炭气化制甲醇技术,采用6MPa纯氧高压气化制合成气（CO＋H2）,合成气可产双倍的甲醇,则1t甲醇的煤耗仅为1.3～1.5t,甲醇用作汽车发动机燃料时,以1.3～1.5t甲醇相当于1t汽油作功计算,则煤炭的热能利用率可以达到66%～76%。如果配套水电解制氢技术,还可以实现CO2的零排放。中国每年有20×10^8t的煤炭产量,如果将其中的12×10^8t纳入煤炭气化制甲醇产业链,可每年创造产值约2.67万亿元,可减排CO2约30×10^8t。     

水电解制氢技术的进展及其在煤制甲醇中的应用

介绍了水电解制氢的传统工艺和水电解制氢研究开发动态和发展趋势,展示了太阳能光解水制氢和太阳能光催化水解制氢的研究进展。重点提出了水电解制氢在煤炭气化制甲醇工艺中的应用。介绍了煤气化配水电解氢制甲醇的基本原理,提出了水电解生产流程,并进一步提出了此工艺的工程设想,建议采用壳牌煤气化工艺（SCGP）配水电解氢合成甲醇联产流程,其优点是可实现煤炭中碳元素组分的充分利用,免去传统甲醇工艺中大量的CO2排放。最后建议对该创新工艺设想进行循序渐进的开发,以尽快实现工业化推广应用。     

煤气化发电与电解水制氢联产干冰工艺路线设想

推荐煤气化发电与电解水制氢联产干冰的工艺路线。该工艺以煤炭、空气和水为原料,干粉煤纯氧高温(1700℃)气化全部转化成合成气(CO+H_2),用脱硫后的纯合成气CO含63%以上的部分合成气作电解水制氢的循环介质,可使制氢的电耗由4.76k W·h/m~3 H_2(标准状态)降到1.67k W·h/m3 H_2(标准状态)。同时CO在水电解阳极同水中的氧变换成CO_2(或CO_2+O_2)。阳极排出的CO_2浓度可调节成79%CO_2+21%O_2,用于燃气轮机发电助燃剂,排出的烟气为高温纯CO_2,进入废锅产高压蒸汽用于发电后经冷却节流膨胀成雪花状固体CO_2干冰,可用作植物肥料。水电解阴极取得纯H_2产品,可用于合成气中配H_2,用于合成甲醇。于是电解水槽成为用电能分解水和合成气用于发电和生产化工产品原料气的转化调节核心装置,其调整负荷控制在40%以内,成为调节电力与化工产品生产的经济可行的创新技术。     

煤制清洁低碳能源的技术经济评价

一、煤制清洁能源的技术路线和主要技术 （一）技术路线煤炭经过加工，制备出适合煤转化工艺需要的原料煤。不同的煤转化工艺对灰分、硫分、粒度、水分等都各有具体的要求。原料煤经过气化，生产出粗煤气，经过煤气净化和变换，产生出一定的H2CO合成气（H2＋CO）；通过脱碳工艺，生产出高浓度的CO2，可注入油田、煤层，提高石油开采收率和煤层气产量。     

页岩气自热转化等压合成60×10~4t/a甲醇工艺设计

我国页岩气资源丰富,是替代石油生产乙丙烯的原料。美国页岩气为原料生产乙烯的成本仅为石油制乙烯的38%。页岩气生产合成气制甲醇,再生产乙丙烯的生产过程采用组合生产工艺,包括页岩气纯氧自热转化制合成气,合成气在等压下直接合成甲醇,省去了合成气压缩机,副产高压蒸汽作空分空压机动力平衡能源,不需燃料加热,无燃气CO2排放。页岩气自热转化制得的合成气在H2-CO/CO+CO2=2.1~2.2,压力5MPa下合成甲醇,甲醇合成采用气冷和水冷串联合成,提高了合成转化率,合成甲醇浓度很高,省去了甲醇精馏。甲醇制烯烃采用甲醇脱水制烯烃(MTO)工艺,MTO工艺原料需求低,原料消耗少,烯烃收率高,乙烯、丙烯可调性大,产品分离简单方便,材质要求低。由甲醇催化制得的烯烃气体不含有机硫化物和乙炔,省去了十分复杂的烯烃分离工艺,所以甲醇制乙烯比石油制乙烯具有较大的竞争力,是今后乙烯工艺技术的发展方向。设计的4.8×108m3页岩气制60×104t/a甲醇,再生产24×104t/a乙丙烯组合工艺总投资约为26亿元,年利税9.94亿元,投产后约3年即可回收投资。     

天然气纯氧自热转化制甲醇节气增产减排CO2工艺的实践

内蒙古苏里格甲醇厂一套天然气制甲醇合成气的装置原采用一段外热蒸汽转化工艺．甲醇生产能力为18×10^4t／a。与外加热蒸汽转化工艺相比,轻烃自热转化大约用1m^3 O2可替代0．5m^3 CH4,采用天然气纯氧自热转化制甲醇合成气的两段转化工艺（增设二段炉）进行改造,可增加甲醇生产能力15×10^4t/a,配套改造投产后甲醇生产能力可达到33×10^4t／a,改造后生产甲醇的天然气消耗量由1100m^3／t（标准）下降为960m^3／t（标准）。所用自热转化工艺采用多气流转化炉与低温混合喷射外燃式烧嘴配套的创新技术,该技术的成功应用,达到了节气12．7％、增产83．3％的目的。采用该新工艺生产甲醇合成气可节省原料天然气20％～30％,减排CO2 70％～95％。     

连续式超临界水中煤/CMC催化气化制氢

在向水煤浆中添加CMC（羧甲基纤维素钠），成功实现水煤浆高压均匀输送基础上，对超临界水中煤／CMC催化气化制氢性能进行了进一步研究。结果表明：在压力20～25MPa、停留时间15～30s、NaOH添加量0．1％、反应器外壁温650℃条件下，超临界水中煤/CMC催化气化制氢气体产物中H2摩尔含量远比常规气化高，主要气体产物是H2、CO2和CH4。增加物料中CMC的含量、升高压力均有利于提高气体产物中心的产量，延长停留时间虽有利于物料气化但不利于氢气的制取。     

推广煤层气非催化法制甲醇工程总承包单位

煤层气非催化法制甲醇是多家单位联合设计、开发的非催化法制联合成气工业化项目之一,推广总承包单位主要有:“中国泽楷集团能源化工专家院”,隶属于中国泽楷(集团)有限公司,汇聚了国内能源化工界的一流专家,适应国家能源结构调整战略,发挥自身特有优势,主要从事粉煤气化同水电解氢制甲醇(CO2零排放)等新能源先进工程技术的设计、推广及工业应用;“重庆理想科技有限公司”,长期从事轻烃和煤炭制取合成气的开发、研究和设计,甲醇、二甲醚的生产(拥有二甲醚专有技术)及二甲醚、MDEA脱     

新疆沙尔湖煤气化过程影响因素研究

应用Aspen Plus模拟软件建立了新疆沙尔湖煤气流床气化过程的计算模型,并对新疆沙尔湖煤的气化过程进行模拟计算。以粗合成气中(H2+CO)摩尔分数和有效气产量最高为目标函数,研究了主要参数对气化结果的影响,确定出最佳气化工艺条件。     

Technoeconomic analysis of a methanol plant based on gasification of biomass and electrolysis of water

Methanol production process configurations based on renewable energy sources have been designed. The processes were analyzed in the thermodynamic process simulation tool DNA. The syngas used for the catalytic methanol production was produced by gasification of biomass, electrolysis of water, CO₂ from post-combustion capture and autothermal reforming of natural gas or biogas. Underground gas storage of hydrogen and oxygen was used in connection with the electrolysis to enable the electrolyser to follow the variations in the power produced by renewables. Six plant configurations, each with a different syngas production method, were compared. The plants achieve methanol exergy efficiencies of 59–72%, the best from a configuration incorporating autothermal reforming of biogas and electrolysis of water for syngas production. The different processes in the plants are highly heat integrated, and the low-temperature waste heat is used for district heat production. This results in high total energy efficiencies (∼90%) for the plants. The specific methanol costs for the six plants are in the range 11.8–25.3 €/GJ_exergy. The lowest cost is obtained by a plant using electrolysis of water, gasification of biomass and autothermal reforming of natural gas for syngas production.     

Effect of the type of gasifying agent on gas composition in a bubbling fluidized bed reactor

It is commonly accepted that gasification of coal has a high potential for a more sustainable and clean way of coal utilization. In recent years, research and development in coal gasification areas are mainly focused on the synthetic raw gas production, raw gas cleaning and, utilization of synthesis gas for different areas such as electricity, liquid fuels and chemicals productions within the concept of poly-generation applications. The most important parameter in the design phase of the gasification process is the quality of the synthetic raw gas that depends on various parameters such as gasifier reactor itself, type of gasification agent and operational conditions. In this work, coal gasification has been investigated in a laboratory scale atmospheric pressure bubbling fluidized bed reactor, with a focus on the influence of the gasification agents on the gas composition in the synthesis raw gas. Several tests were performed at continuous coal feeding of several kg/h. Gas quality (contents in H₂, CO, CO₂, CH₄, O₂) was analyzed by using online gas analyzer through experiments. Coal was crushed to a size below 1 mm. It was found that the gas produced through experiments had a maximum energy content of 5.28 MJ/Nm³ at a bed temperature of approximately 800 °C, with the equivalence ratio at 0.23 based on air as a gasification agent for the coal feedstock. Furthermore, with the addition of steam, the yield of hydrogen increases in the synthesis gas with respect to the water–gas shift reaction. It was also found that the gas produced through experiments had a maximum energy content of 9.21 MJ/Nm³ at a bed temperature range of approximately 800–950 °C, with the equivalence ratio at 0.21 based on steam and oxygen mixtures as gasification agents for the coal feedstock. The influence of gasification agents, operational conditions of gasifier, etc. on the quality of synthetic raw gas, gas production efficiency of gasifier and coal conversion ratio are discussed in details.     

Experimental simulate on hydrogen production of different coals in underground coal gasification

Research on hydrogen production from coal gasification is mainly focused on the formation of CO and H₂ from coal and water vapor in high-temperature environments. However, in the process of underground coal gasification, the water gas shift reaction of low-temperature steam will absorb a lot of heat, which makes it difficult to maintain the combustion of coal seams in the process of underground coal gasification. In order to obtain high-quality hydrogen, a pure oxygen-steam gasification process is used to improve the gasification efficiency. And as the gasification surface continues to recede, the drying, pyrolysis, gasification and combustion reactions of underground coal seams gradually occur. Direct coal gasification can't truly reflect the process of underground coal gasification. In order to simulate the hydrogen production laws of different coal types in the underground gasification process realistically, a two-step gasification process (pyrolysis of coal followed by gasification of the char) was proposed to process coal to produce hydrogen-rich gas. First, the effects of temperature and coal rank on product distribution were studied in the pyrolysis process. Then, the coal char at the final pyrolysis temperature of 900 °C was gasified with pure oxygen-steam. The results showed that, the hydrogen production of the three coal chars increased with the increase of temperature during the pyrolysis process, the hydrogen release from Inner Mongolia lignite and Xinjiang long flame coal have the same trend, and the bimodality is obvious. The hydrogen release in the first stage mainly comes from the dehydrogenation of the fat side chain, and the hydrogen release in the second stage mainly comes from the polycondensation reaction in the later stage of pyrolysis, and the pyrolysis process of coal contributes 15.81%–43.33% of hydrogen, as the coal rank increases, the hydrogen production rate gradually decreases. In the gasification process, the release of hydrogen mainly comes from the water gas shift reaction, the hydrogen output is mainly affected by the quality and carbon content of coal char. With the increase of coal rank, the hydrogen output gradually increases, mainly due to the increasing of coal coke yield and carbon content, The gasification process of coal char contributes 56.67–84.19% of hydrogen, in contrast, coal char gasification provides more hydrogen. The total effective gas output of the three coal chars is 0.53–0.81 m³/kg, the hydrogen output is 0.3–0.43 m³/kg, and the percentage of hydrogen is 53.08–56.60%. This study shows that two-step gasification under the condition of pure oxygen-steam gasification agent is an efficient energy process for hydrogen production from underground coal gasification.     

Life cycle assessment of various hydrogen production methods

A comprehensive life cycle assessment (LCA) is reported for five methods of hydrogen production, namely steam reforming of natural gas, coal gasification, water electrolysis via wind and solar electrolysis, and thermochemical water splitting with a Cu–Cl cycle. Carbon dioxide equivalent emissions and energy equivalents of each method are quantified and compared. A case study is presented for a hydrogen fueling station in Toronto, Canada, and nearby hydrogen resources close to the fueling station. In terms of carbon dioxide equivalent emissions, thermochemical water splitting with the Cu–Cl cycle is found to be advantageous over the other methods, followed by wind and solar electrolysis. In terms of hydrogen production capacities, natural gas steam reforming, coal gasification and thermochemical water splitting with the Cu–Cl cycle methods are found to be advantageous over the renewable energy methods.     

Comparing prospective hydrogen pathways with conventional fuels and grid electricity in India through well-to-tank assessment

The present study uses Greenhouse Gases, Regulated Emissions, and Energy Use in Technologies Model (GREET), to compare hydrogen generated via multiple pathways (Natural gas, methanol reforming; coal, petcoke, biomass gasification etc) with the conventional fuels like diesel and compressed natural gas and grid electricity under Indian context through a comprehensive well to tank assessment based on net CO₂ equivalent emission and energy consumption. Limited availability of customized studies comparing hydrogen production and supply with other energy options in India distinguishes the present work as it provides a fresh insight into potential pathways for hydrogen production while assessing feedstock availability and raw water consumption. The study reveals that biomass gasification and solar electrolysis are among the least GHG emitting pathways to fill one unit of energy equivalent in the tank. Hydrogen produced through natural gas reforming is 70% less emission intensive and 38% more energy efficient than Indian grid electricity.     

Hydrogen production and technology: today,tomorrow and beyond

Hydrogen is produced on a large scale by a wide variety of processes starting with feedstocks like natural gas, crude oil products to coal as well as water-using processes like steam reforming, partial oxidation, coal gasification, metal-water processes and electrolysis. Hydrogen is also recovered from various gas streams especially in refineries.Depending on the basic energy scenarios to be used, steam reforming natural gas will remain the major hydrogen source from today till tomorrow, i.e. the turn of the century. Coal gasification will significantly increase in its share for hydrogen production. This will be achieved via newly developed coal gasification processes.The development of thermochemical hydrogen production technology as well as biological hydrogen production technologies will progress, but their widespread application remains to be seen in the next century.     

The Canadian synthetic fuel industry—a major user of hydrogen

Oil sands and coal will be the dominant future sources of synthetic fuels in Canada. Proved recoverable reserves of oil sands are equivalent to 54 y of supply at current petroleum production rates; established recoverable coal reserves could meet both Canada's petroleum and coal requirements (at current production rates) for 58 y. It is expected that advances in technology will extend these figures by many hundreds of years.Current production from oil sands is equivalent to roughly 10% of Canada's petroleum energy demand. The hydrogen requirement for the existing oil sand plants is 160 million scf per day, and this figure is expected to increase to at least 1000 million scf per day before the year 2005. Natural gas is the current source of hydrogen but coke gasification and electrolysis of water are potential future sources of supply. A combination of coke gasification and electrolysis, with the oxygen generated from the latter being used for the gasification reaction, shows promise.No commercial coal conversion plants exist in Canada, but extensive laboratory and bench unit testing of both pyrolysis and liquefaction processes are underway. Two-staged liquefaction processing has been shown to give higher liquid yields with lower hydrogen consumption and warrants further research and development. Due to the lower hydrogen content of coal, the hydrogen requirements for coal liquefaction plants will be more than double that of oil sand plants of equivalent output.