第二章_化石燃料制氢[1].ppt

单击此处编辑母版标题样式,单击此处编辑母版文本样式,第二级,第三级,第四级,第五级,*,单击此处编辑母版标题样式,单击此处编辑母版文本样式,第二级,第三级,第四级,第五级,第,2,章 化石燃料制氢,王智化,浙江大学,热能工程研究所,能源清洁利用国家重点实验室,氢气大规模制取的原理及方法,Why need new Energy?,Pollutions,Greenhouse Earth,Energy consumption in the world,Energy consumption in China,Nowadays,energy supply of the whole world was mainly based on the combustion of fossil fuels,such as coal,oil and natural gas.,Lots of problem will arise from the combusiton,PM2.5,Aerosol,SO,2,NO,x,Hg,CO,2,.,Hydrogen:fuel of the future?,Hydrogen is a kind of excellent Energy Carrier;,The most distinguished utilization of H,2,is Fuel Cell for its high efficiency and no pollution generated;,Its attractive for transportation.,3Kg of H,2,can run 500km.,Generation,Storage,Utilization,Distribution,Sustainable,H2,Economy,不同制氢方法及原料,Fossil fuels,Biomass,Water,Steam reforming,Partial oxidization,Thermal cracking,Coal gasification,Water electrolysis,Thermolysis,Thermal chemical cycles,Photolysis,H,2,S pyrolysis,Bacteria fermentation,Source,Method,H,2,Others,化石燃料制氢,目前全球,H,2,产量在,5,千万吨,/,年左右，且年增长率,6%,7%,。,全球商业用,H,2,大约,96%,由煤、石油和天然气等化石燃料制取。,我国生成的,H,2,有,80%,以上用于合成氨工业,，而合成氨以煤为主，无烟煤、焦炭占,62,65%,，轻油和重油占,12,16%,，天然气占,18,23%,。,虽然制氢消耗有限的化石燃料储量，但在先进、成熟的制氢方法出现之前，在未来几十年仍然扮演重要角色。,世界产氢原料对比,2.1,天然气制氢,煤的碳氢比远高于石油和天然气，而,挥发分的碳氢比与石油和天然气接近，,故煤部分气化得挥发份较易转化为油气产品。,石油炼化,及,合成氨化肥,行业是最大的,H,2,用户。,先进的制氢技术多是由大型石油企业推动，,如,SHELL,，,TEXCO,，,LUGI,等。,天然气含,H,2,最高，可以作为,H,源之一。,神华煤制油项目天然气制氢,烟煤,平均,18/1,（挥发分,5.5/1,）,褐煤,平均,13/1,（挥发分,2.6/1,）,石油,7/1,天然气,3/1,主要化石燃料的碳,/,氢比,2.1.1,天然气水蒸汽重整制氢,起步于,20,世纪,20,年代，,20,世纪,70,年代，英国帝国化工公司，开发了弱碱催化剂用于天然气水蒸汽重整制氢，大规模应用并沿用至今。,两个反应在一段反应炉内完成，反应温度,650,850,，反应管出口温度,820,。,若原料按下式进行配比，可获得,CO:H,2,=1:2,的合成气：,可见该反应是强吸热反应，需要吸收大量的热量，因此该过程能耗较高。,燃料成本占生产成本的,5268%,，另外反应速度慢，需要昂贵的耐热不锈钢。,Reformer,的内部结构,The Steam Reformer Process,FLOW CHART OF A STEAM REFORMER:1 Feed Pre-Treatment 2 Reforming&Steam Generation 3 High Temperature Conversion 4 Heat Exchanger Unit 5 Purification Unit*optional,depending on reformer design a either heat exchanger for low pressure reformer or compression to 1 bar for high pressure reformer Flow Chart of a Steam Reformer,desulphurised using e.g.activated carbon filters,900,in the presence of a nickel catalyst,Hydrogen purification is achieved by means of pressure swing adsorption(PSA),天然气重整及其努力方向,天然气重整技术为成熟商业技术。,主要问题：,关键在于,H,2,从,CO,等混合气中的分离，目前的,pressure swing absorption,成本昂贵；,CO,2,回收成本高,采用的对策,：,利用膜分离技术，分离出氧气，用氧气燃烧部分天然气提供热量，用膜分离出,H,2,。,CO,2,得到富集。,2.1.2,天然气部分氧化重整制氢,变强吸热为温和放热，因而具有能耗低的显著特点，且空速高，设备小，投资低。,由于甲烷部分氧化反应可实现自然反应，不需要外界提供额外热量，因此设备简化，投资成本低。,但对于运行要求高，需大量纯氧。,当氧含量,1012%,，,5,30MPa,下主要生成甲醇、甲醛和甲酸；,当氧含量,3537%,，在,1300,，反应气体快速冷却获得乙炔；,再增加氧量，生成,CO,和,H,2,；,当量比氧量，生成,CO,2,和,H,2,O,。,为防止析碳，在反应系统中往往加入,H,2,O,，调节反应温度和气体组成，因此下述反应同时进行：,美国努力发展的未来先进天然气制氢技术,关键点：,1,）采用多种金属氧化物制成的无孔陶瓷膜，在大于,700C,的温度下，导电以及氧离子；,2,）天然气的部分氧化制氢；,3,）混合气进入水煤气转换反应器；,4,）采用,PSA,技术分离,H,2,；,5,）高浓度,CO,2,捕获。,2.1.3,天然气裂解制氢,天然气与空气当量比混合燃烧，待温度达到,1300,以上时，停止供,Air,，仅送天然气，使之在高温下裂解生成,H2,和炭黑。由于吸热造成温度下降至,100,0,1200,时，再次通入空气燃烧。,炭黑、颜料与印刷工业有多年应用历史。,天然气中低碳烷烃在高温下吸收大量能量而分解为低碳不饱和烃和氢，甚至完全分解为元素碳和氢的烃类裂解过程。天然气热裂解过程比较复杂，主要反应有,2.2,液体化石燃料制氢,-,甲醇裂解制氢,由于,H,2,难以储存，单位体积能量密度低，高压储氢耗能大，因此考虑甲醇的现场裂解制氢。,甲醇燃料电池。,2.3,煤气化制氢,IGCC,详细流程,Utilization of syngas,美国的未来煤制氢技术,核心：,以煤气化为基础制氢：,1,）膜分离技术：,包括,H,2,的分离，,O,2,的分离；,2,）煤气化技术产,H,2,。,煤气化产气组份：,H,2,34.4%,CO 45.3%,CO,2,15.8%,CH,4,1.9%,气化炉,温度：,1371C,压力：,27.6bar,煤气化示范工程,2000.9,月完成 模拟结果,C/O2/H2O=1:0.35:1,H2,CO,CO2,CH4,34.38%,50.9%,14.7%,0.02%,煤制氢技术及努力方向,当前技术采用煤的部分氧化、气化技术；,混合煤、氧、水蒸气产生混合气，用成熟的水煤气转化反应器产生更多的,H,2,同时把,CO,转化为,CO,2,；用,PSA,技术分离,H,2,。,主要的研究目标：,1.,采用高效耐硫催化剂的高级水煤气转换反应器；,2.,管内的膜分离技术；,3.H,2,分离与水煤气转换一体反应器；,4.,用最少的步骤分离,CO,2,H,2,S,以及其它杂质,煤气化炉,气化反应过程,固定床气化炉,Lugi,Lurgi GmbH first developed Lurgi dry-ash gasification technology in the early 1930s to produce what was still known as town gas,in one of the first practical applications of gasification.,An estimated 150 Lurgi gasifiers are in operation today,mainly in South Africa,China and the United States(North Dakota).,The Lurgi gasifier is a pressurized,dry-ash,moving bed gasifier that produces syngas from lump coal,steam,and oxygen as an oxidant.,A top temperature of about 1,000F and bottom temperature of about 1,800F creates a temperature gradient in the gasifier.Exiting raw syngas at up to 1,000F.,Sasols,synfuel coal-to-liquids facilities in South Africa producing Fischer-Tropsch liquids and chemicals.,Great Plains Synfuels Plant,in North Dakota producing SNG,as well as ammonia,phenol,and carbon dioxide as byproducts.,SNG,The Great Plains Synfuels Plant(GPSP)in Beulah,North Dakota has been in operation producing synthetic natural gas(SNG)from lignite coal for 25 years and remains the only coal-to-SNG facility in the United States.In addition to the production of SNG,the plant also produces high purity carbon dioxide(CO,2,),which is distributed through a pipeline to end users in Canada for enhanced oil recovery(EOR)operations.,水煤浆气流床气化炉,Texaco,（,GE,）,Coal water slurry feed,better fluidity,convenient transportation,no deflagrate risk,but complicated pump for cws,pressurized entrained-flow,4.3-8.3MPa,to enhance production,Wider coal adaptability,longer resident time,Temperature in furnace:1623,1773K,Shorts:short lifetime of nozzle,more O,2,consumption,require of firebrick,Texaco,E-Gas Entrained-flow Gasifier,The E-Gas coal gasifier is a pressurized,upflow,entrained,slagging design with a unique two-stage operation.Like the GE gasifer,E-Gas is a slurry-feed gasifier.Wet crushers produce slurries from the raw feed coal.,About 75%of the total slurry feed is fed to the first(or bottom)stage of the gasifier through mixer nozzles,along with 95%pure oxygen.This stage involves,highly exothermic oxidation,reactions and operates at typically 2,600F and 400 psig.,Hot synthesis gas(syngas)from the first stage then enters the second(top)stage where the remaining slurry feed is injected.,Endothermic gasification and devolatization reactions take place at 1,900F,resulting in the formation of some,hydrocarbons,in the product gas and the production of char,which are both recycled to the first stage where they are readily gasified.,干煤粉气化炉,SHELL,Raw coal-pulverized coal(100um)-dry-feeder-N,2,transport-nozzle,Air separate unit-O,2,-pressure and preheat-mix with superheat steam-nozzle,Pulverized coal,O,2,and steam react high P and T.,High T coal gas-cooler-1173K-waste heat boiler,Temperature 1673-1873K,99%C conversion,cleaner product gas,15-25%O,2,consumption lower than Texaco,different with other gasifiers:adoption of water wall and side wall nozzle,which centre symmetry with 4-8 nozzles in terms of gasification ability,Shell Gasifier with Membrane Wall,流化床气化炉,Winkler,Pulverized coal,screw feeder,Big throughput,but lower calorific value,when air and steam as gasification agent,4.65MJ/Nm,3,;,when O,2,as gasification agent,10.54MJ/Nm,3,.,Simple technics and equipment,trustiness and mature.,Low temperature,only active brown and sub-bituminous coal can be used.,Normal pressure,weaker gasification capability,production and calorific value.,Gasification efficiency 74.9%,C conversion 90.6%.,几种典型气化炉对比,gacifier,Gasification agent,feed,P/MPa,T/K,gasification efficiency,state,Texaco,(America),99.6%O,2,Coal water slurry(pump),4-6.5,1623-1773,70-76%,Use more,but faulty,SHELL,(holand),Pure O,2,and steam,Pulverized coal(N,2,),(screw feeder),2-4,1673-1873,80-83%,More perfect,but expensive,winkler,O,2,and steam,/air and steam,Pulverized coal(N,2,),(screw feeder),normal,1073-1273,75%,Water gas,steam,Coal or C,normal,1273,60-65%,Comparison of different gasifier,gasifier,CO,H,2,CO,2,CH,4,N,2,LCV/MJ/Nm,3,Texaco,49.3,36.0,12.8,0.4,0.9,10.2518,SHELL,65.1,25.6,0.8,0.01,8.03,10.9851,Winkler,(,air blow),22.5,12.6,7.7,0.7,55.7,4.4509,Water gas,37,50,7,0.5,5.5,10.2451,Comparison of gas composition,地下煤气化技术,Underground Coal Gasification,UCG；,改变传统的煤矿开采工艺；,地下气化方法类型：,有井式,无井式,气化剂的选择：,空气,氧气+水蒸气,富氧+水蒸气,地下气化的控制方法,控制压风量,煤气产量,UCG技术现状,前苏联是世界上第一个实现地下煤气化工业应用成功的国家，1932年在顿巴斯建立了世界上第一座有井式气化站；到20世纪60年代已建27座气化站，所生产煤气用于发电或工业锅炉燃烧。,美国地下气化试验始于1946年，70年代能源危机，投入大量人力物力开发，1988年的洛基出-1号试验，取得了大型化的经验和数据。技术工艺有：控制后退供风点法、急倾斜煤层法。,适用对象：2000m以下的深层煤炭资源开采，废弃矿井残留资源的开发利用；,零排放系统,Zero emission system,气化炉,：吸收剂如,CaO,等吸收,CO,2,后释放气化过程所需,热量，并进行气化反应,再生炉,：碳酸化后产物吸热分解再生,CO,2,吸收剂颗粒,蒸汽,富,H,2,气体：,燃料电池等,富,CO,2,气体：,处理,含碳燃料,碳酸化后的吸收剂,未气化半焦,气化炉,再生炉,O,2,或外来热源,CO,2,吸收剂颗粒,CO,2,固体吸收的含碳燃料气化制氢,化学链气化系统,气化炉,CO,2,接受体无氧气化过程,气化炉中所发生的主要反应为：,C+H,2,O=CO+H,2,-131.6kJ/mol,CH,4,+H,2,O=CO+3H,2,-206.3kJ/mol,CO+H,2,O=CO,2,+H,2,+41.5kJ/mol,CaO+CO,2,=CaCO,3,+178.1kJ/mol,H,2,S+CaO=CaS+H,2,O,蒸汽,富,H2,气体,CO,2,含碳燃料,CaO,Char,、,CaCO,3,CaO,Gasifier,Combustor,O,2,燃烧炉,实现半焦的燃烧放热,及,CaCO,3,的煅烧分解,燃烧炉发生的主要反应为：,CaCO,3,=CaO+CO,2,-178.1kJ/mol,C+O,2,=CO,2,+393.791kJ/mol,Steam,富,H2,气体,CO,2,含碳燃料,CaO,Char,、,CaCO,3,CaO,Gasifier,Combustor,O,2,系统性能参数,(467MWe,系统）,项目,数值,项目,数值,烟煤给煤量（,kg/s,）,30,燃料电池发电率,(MW),299,气化炉压力,(bar),20,烟气轮机发电量（,MW,）,308,气化炉运行温度,（）,850,蒸汽汽轮机发电,(MW),38,气化率,0.75,空分耗电,(MW,）,76,氢产率,(mol/s,）,1.16,压缩机耗电,(MW,）,95,燃烧炉压力,(bar),20,净发电量（,MW,）,467,燃烧炉温度,（）,963,发电效率（）,59.3,CONOCO,公司,1972,年开发的,CaO,受体煤气化反应装置,目的：生产天然气代用气,运行压力,1.03MPa,；,气化炉,850,845C,；,再生炉,1010C,；,优点：,1,）可以达到很高的碳转化率；,2,）不用空气分离装置就可以产出不含,N2,的产品气；,缺点：,1,）接受体更换费用高；,2,）固体接受体传输系统会发生腐蚀，需采用陶瓷衬里管道；,3,）只使用褐煤和某些次烟煤，气化前需干燥，热量消耗大,.,以上述技术为基础的近零排放系统,美国,KIRILL V.,1996,工作压力：,10bar,；,气化炉温度,800C,左右；,再生炉温度：,1030,左右；,固体氧化燃料电池，利用,H2,CO,发电,高压可以提高燃气轮机循环效率；但压力上限一般为,25,30bar,，高压下水煤气转换反应需要更多热量，同时,CaCO3,的分解被抑制,我们所采用的近零排放煤气化燃烧利用系统简介,在压力循环流化床气化炉中，利用煤与水蒸气反应，制取,H,2,。,H,2,净化后送入燃料电池发电。产生的,CO,利用水煤气反应最大限度生成,CO,2,，利用,CaO,吸收过程产生的,CO,2,，从而使气化产物主要为高品质的,H,2,。,煤中低活性成份送入流化床燃烧炉，与燃料电池费气一起燃烧，烟气带动燃气轮机发电，尾气热量采用余热锅炉充分利用，带动低参数蒸汽轮机组做功。同时在炉中完成,CaCO,3,的分解反应，,CaO,送入气化炉循环使用。,过程产生的高浓度,CO,2,便于尾部分离处理。燃烧炉中产生的,SO,2,，会与,CaO,反应生成,CaSO,4,，从而加以脱除，煤中的含,N,组份在气化炉中环境下主要转化成为,N,2,。从而实现整个过程的近零排放。,化学反应模型,纯碳的总包反应：,1mol C,制取,2 mol H,2,C+2H,2,O+CaO=CaCO,3,+2H,2,+88KJ/mol,低挥发份烟煤的总包反应：,1mol C,制取,3.3 mol H,2,3,C+8H,2,O+4CaO+CH,4,=4CaCO,3,+10H,2,+277.3KJ/mol,高挥发份烟煤的总包反应：,1mol C,制取,6 mol H,2,C+4H,2,O+2CaO+CH,4,=2CaCO,3,+6H,2,+101.3kJ/mol,1.C+H,2,O=CO+H,2,131.6KJ/mol,2.CO+H,2,O=CO,2,+H,2,41.5KJ/mol,3.CaO+CO,2,=CaCO,3,178.1KJ/mol,4.CH,4,+H,2,O=CO+3H,2,206.3KJ/mol,制氢过程的几个重要基础反应：,近零排放煤气化燃烧集成系统,压力对于制氢过程影响,以,900C,为基础,压力越高，,H2,的生成量越少；,低压条件下,H2O,CO,CO2,含量也比较高。,纯碳反应过程绝对生成,Mol,数量,压力对于制氢过程影响,以,900C,为基础,在低压条件下，随压力升高,H2,含量呈下降趋势，在,20bar,左右呈最小值，其原因为,H2O,CH4,含量的快速增加所至。,高压条件下，,H2,含量增加并趋于平稳。原因是因为,CO,CO2,含量的降低，同时,H2O,CH4,含量的增加，高压情况下,H2,含量趋于稳定，均大于,50,。,1.C+H2O=CO+H2,131.6KJ/mol,2.CO+H2O=CO2+H2,41.5KJ/mol,3.CaO+CO2=CaCO3,178.1KJ/mol,4.CH4+H2O=CO+3H2,206.3KJ/mol,H,2,O最终0.56mol,初始2mol,H,2,O利用率72,气化温度影响,以,7MPa,为基础,低温条件下，,CH,4,、,H,2,O,含量较高。,高温条件下，由于,CaCO,3,的重新分解，造成,CO,CO,2,含量大大增加。,该压力条件下的理想温度范围在,700,900C,1.C+H2O=CO+H2,131.6KJ/mol,2.CO+H2O=CO2+H2,41.5KJ/mol,3.CaO+CO2=CaCO3,178.1KJ/mol,4.CH4+H2O=CO+3H2,206.3KJ/mol,低压,1bar,条件下,H,2,max,的最佳温度,最佳温度范围,500600C,，,H2,产量达到,78%,如果可以工作在,500,600C,条件下，那么,1bar,是最优的，,H2,产量干燥下可以达到,90,以上,不同压力最佳温度下制,H2,情况,1Bar,25Bar,50Bar,70Bar,100Bar,最佳温度,C,600,750,800,800,850,H2,78,60.5,56.7%,54.7,52.5%,CO,0.98,1.1%,0.7%,0.89,1.58%,CO2,0.47,0.59%,1.37%,0.53,0.85%,CH4,6.5,12.2,13.3%,14.3,14.5%,H2O,13.9,25.4%,27.9%,29.6,30.5%,H,2,O/C,配比变化,对于淮南煤，最佳的,H,2,O/C,摩尔比为,2.67,当,H,2,O,不足时，反应进行不彻底；,当,H,2,O,过剩时，,H,2,O,利用率低，影响,H,2,含量。,系统质量平衡能量平衡,