氢燃料电池技术英文Hydrogen Fuel Cell Technology

1、Hydrogen Fuel Cell TechnologyWill it contribute to energy independence?Stephen Cohen and Nathan BonnettMay 18, 2007FUEL CELL TECHNOLOGYTechnology overviewHydrogen fuel developmentLaw, legislation, and administrative agency treatmentWhat is a Fuel Cell?A Fuel Cell is an electrochemical device that co

2、mbines hydrogen and oxygen to produce electricity, with water and heat as its by-product.Why is Fuel Cell Technology Important?Since conversion of the fuel to energy takes place via an electrochemical process, not combustionIt is a clean, quiet and highly efficient process- two to three times more e

3、fficient than fuel burning. How does a Fuel Cell work?It operates similarly to a battery, but it does not run down nor does it require rechargingAs long as fuel is supplied, a Fuel Cell will produce both energy and heatHow does a Fuel Cell work?A Fuel Cell consists of two catalyst coated electrodes

4、surrounding an electrolyteOne electrode is an anode and the other is a cathodeHow does a Fuel Cell work?The process begins when Hydrogen molecules enter the anodeThe catalyst coating separates hydrogens negatively charged electrons from the positively charged protonsHow does a Fuel Cell work?The ele

5、ctrolyte allows the protons to pass through to the cathode, but not the electrons Instead the electrons are directed through an external circuit which creates electrical currentHow does a Fuel Cell work?While the electrons pass through the external circuit, oxygen molecules pass through the cathodeT

6、here the oxygen and the protons combine with the electrons after they have passed through the external circuitWhen the oxygen and the protons combine with the electrons it produces water and heatHow does a Fuel Cell work?How does a Fuel Cell work?Individual fuel cells can then be placed in a series

7、to form a fuel cell stackThe stack can be used in a system to power a vehicle or to provide stationary power to a buildingMajor Types of Fuel CellsIn general all fuel cells have the same basic configuration - an electrolyte and two electrodesDifferent types of fuel cells are classified by the kind o

8、f electrolyte usedThe type of electrolyte used determines the kind of chemical reactions that take place and the temperature range of operationMajor Types of Fuel CellsProton Exchange Membrane (PEM)This is the leading cell type for passenger car applicationUses a polymer membrane as the electrolyteO

9、perates at a relatively low temperature, about 175 degreesHas a high power density, can vary its output quickly and is suited for applications where quick startup is required making it popular for automobilesSensitive to fuel impuritiesMajor Types of Fuel Cells Direct Methanol (a subset of PEM)Expec

10、ted efficiencies of 40% plus low operating temperatures between 120-190 degreesAlso uses a polymer membrane as the electrolyteDifferent from PEM because the anode catalyst is able to draw hydrogen from methanol without a reformerUsed more for small portable power applications, possibly cell phones a

11、nd laptopsMajor Types of Fuel CellsPhosphoric AcidThis is the most commercially developed fuel cellIt generates electricity at more than 40% efficiencyNearly 85% of the steam produced can be used for cogenerationUses liquid phosphoric acid as the electrolyte and operates at about 450 degrees FOne ma

12、in advantage is that it can use impure hydrogen as fuel Major Types of Fuel CellsMolten CarbonatePromises high fuel-to-electricity efficiency and the ability to utilize coal based fuelsUses an electrolyte composed of a molten carbonate salt mixture Require carbon dioxide and oxygen to be delivered t

13、o the cathode Operates at extremely high temperatures 1200 degrees Primarily targeted for use as electric utility applicationsHave been operated on hydrogen, carbon monoxide, natural gas, propane, landfill gas, marine diesel and simulated coal gasification productsMajor Types of Fuel CellsMolten Car

14、bonate Fuel CellBecause of the extreme high temperatures, non-precious metals can be used as catalysts at the anode and cathode which helps reduces costDisadvantage is durabilityThe high temperature required and the corrosive electrolyte accelerate breakdown and corrosion inside the fuel cellMajor T

15、ypes of Fuel CellsSolid OxideUses a hard, non-porous ceramic compound as the electrolyteCan reach 60% power-generating efficiencyOperates at extremely high temperatures 1800 degrees Used mainly for large, high powered applications such as industrial generating stations, mainly because it requires su

16、ch high temperaturesMajor Types of Fuel CellsAlkalineUsed mainly by military and space programsCan reach 70% power generating efficiency, but considered to costly for transportation applicationsUsed on the Apollo spacecraft to provide electricity and drinking waterUses a solution of potassium hydrox

17、ide in water as the electrolyte and operates at 75 -160 degreesCan use a variety of non-precious metals as catalyst at the anode and cathodeMajor Types of Fuel CellsAlkaline Fuel CellRequires pure hydrogen and oxygen because it is very susceptible to carbon contaminationPurification process of the h

18、ydrogen and oxygen is costlySusceptibility to poisoning affects cells lifetime which also affects the cost Major Types of Fuel CellsRegenerative Fuel CellsCurrently researched by NASAThis type of fuel cell involves a closed loop form of power generation Uses solar energy to separate water into hydro

19、gen and oxygenHydrogen and oxygen are fed into the fuel cell generating electricity, heat and waterThe water byproduct is then recirculated back to the solar-powered electrolyser beginning the process againImportance of HydrogenFuel Cells require highly purified hydrogen as a fuelResearchers are dev

20、eloping a wide range of technologies to produce hydrogen economically from a variety of resources in environmentally friendly waysImportance of HydrogenHydrogen is a secondary energy resource, meaning it must be made from another fuelHydrogen can be produced from a wide variety of energy resources i

21、ncluding:Fossil fuels, such as natural gas and coalNuclear energyRenewable resources, such as solar,water, wind and biomass Hydrogen ProductionThe biggest challenge regarding hydrogen production is the costReducing the cost of hydrogen production so as to compete in the transportation sector with co

22、nventional fuels on a per-mile basis is a significant hurdle to Fuel Cells success in the commercial marketplaceHydrogen ProductionThere are three general categories of Hydrogen productionThermal ProcessesElectrolyte ProcessesPhotolytic ProcessesHydrogen ProductionThermal ProcessesNatural Gas Reform

23、ingGasification Renewable Liquid ReformingHydrogen ProductionNatural Gas ReformingSteam Methane ReformingHydrogen is produced from methane in natural gas using high-temperature steamMethane reacts with the steam in presence of a catalyst to produce hydrogenThis process accounts for about 95% of the

24、hydrogen used today in the U.S.Partial oxidation Produces hydrogen by burning methane in airHydrogen Production GasificationProcess in which coal or biomass is converted into gaseous components by applying heat under pressure and in the presence of steamA subsequent series of chemical reactions prod

25、uces a synthesis gas which reacts with steam to produce more hydrogen that can be separatedHydrogen ProductionRenewable Liquid ReformingBiomass is processed to make renewable liquid fuels, such as ethanol or bio-oil, that are then reacted with high-temperature steam to produce hydrogenThis process i

26、s very similar to reforming natural gasHydrogen ProductionElectrolytic ProcessesElectrolytic processes use an electric current to split water into hydrogen and oxygenThe electricity required can be generated by using renewable energy technologies such as wind, solar, geothermal and hydroelectric pow

27、erHydrogen ProductionPhotolytic ProcessesUses light energy to split water into hydrogen and oxygenThese processes are in the very early stages of research but offer the possibility of hydrogen production which is cost effective and has a low environmental impactHydrogen ProductionAuto manufacturers

28、have worked on developing technology that would allow fuel cell cars to continue using gasolineA “reformer on the fuel cell car would convert the gasoline to hydrogen onboard the automobileFunding for this technology has been pulled due to unsatisfactory efficiencyHow will the hydrogen be stored?Dev

29、eloping safe, reliable, compact and cost-effective hydrogen storage is one of the biggest challenges to widespread use of fuel cell technologyHydrogen has physical characteristics that make it difficult to store large quantities without taking up a great deal of spaceHow will the hydrogen be stored?

30、Hydrogen will need to be stored onboard vehicles, at hydrogen production sites, refueling stations and stationary power sitesHydrogen has a very high energy content by weight (3x more than gasoline) and a very low energy content by volume (4x less than gasoline)How will the hydrogen be stored?If the

31、 hydrogen is compressed and stored at room temperature under moderate pressure, too large a fuel tank would be required Researchers are trying to find light-weight, safe, composite materials that can help reduce the weight and volume of compressed gas storage systems How will the hydrogen be stored?

32、Liquid hydrogen could be kept in a smaller tank than gaseous hydrogen, but liquefying hydrogen is complicated and not energy efficientLiquid hydrogen is also extremely sensitive to heat and expands significantly when warmed by even a few degrees, thus the tank insulation required affects the weight

33、and volume that can be storedHow will the hydrogen be stored?If the hydrogen is compressed and cryogenically frozen it will take up a very small amount of space requiring a smaller tank, but it must be kept supercold- around -120 to -196 degrees CelsiusHow will the hydrogen be stored?Scientists are

34、researching Materials-based storageThis involves tightly binding hydrogen atoms or molecules with other elements in a compound to store larger quantities of hydrogen in smaller volumes at low pressure near room temperatureThis technology is considered very promising but additional research is needed

35、 to overcome problems dealing with capacity, cost, life cycle impacts and the uptake and release of hydrogenHow will the hydrogen be stored?Because hydrogen is thought to be an alternative fuel for automobiles, much of the research for hydrogen storage is focused on onboard vehiclesScientists are at

36、tempting to develop technology that can rival the performance and cost of gasoline fuel storage systemsHow will the hydrogen be stored?Using current storage technology, in order to place a sufficient amount of hydrogen onboard a vehicle to provide 300-mile driving range the tank would be larger that

37、 the trunk of a typical automobileThis large of a tank would add to the overall weight of the car and reduce fuel economyHow can Fuel Cell technology be used?TransportationStationary Power StationsTelecommunicationsMicro PowerHow can Fuel Cell technology be used?TransportationAll major automakers ar

38、e working to commercialize a fuel cell carAutomakers and experts speculate that a fuel cell vehicle will be commercialized by 202150 fuel cell buses are currently in use in North and South America, Europe, Asia and AustraliaTrains, planes, boats, scooters, forklifts and even bicycles are utilizing f

39、uel cell technology as wellHow can Fuel Cell technology be used? Stationary Power StationsOver 2,500 fuel cell systems have been installed all over the world in hospitals, nursing homes, hotels, office buildings, schools and utility power plantsMost of these systems are either connected to the elect

40、ric grid to provide supplemental power and backup assurance or as a grid-independent generator for locations that are inaccessible by power linesHow can Fuel Cell technology be used?TelecommunicationsDue to computers, the Internet and sophisticated communication networks there is a need for an incre

41、dibly reliable power sourceFuel Cells have been proven to be 99.999% reliableHow can Fuel Cell technology be used?Micro PowerConsumer electronics could gain drastically longer battery power with Fuel Cell technologyCell phones can be powered for 30 days without rechargingLaptops can be powered for 2

42、0 hours without rechargingWhat are the benefits of Fuel Cell technology?Physical SecurityReliabilityEfficiencyEnvironmental BenefitsBattery Replacement/AlternativeMilitary ApplicationsWhat are the benefits of Fuel Cell technology?Physical SecurityBoth central station power generation and long distan

43、ce, high voltage power grids can be terrorist targets in an attempt to cripple our energy infrastructureFuel Cells allow the country to discontinue reliance on these potential targetsWhat are the benefits of Fuel Cell technology?ReliabilityU.S. businesses lose $29 Billion a year from computer failur

44、es due to power outages More reliable power from fuel cells would prevent loss of dollars for U.S. BusinessesProperly configured fuel cells would result in less than one minute of down time in a six year periodWhat are the benefits of Fuel Cell technology?EfficiencyBecause no fuel is burned to make

45、energy, fuel cells are fundamentally more efficient than combustion systemsAdditionally when the heat comes off of the fuel cell system it can be captured for beneficial purposesThis is called CogenerationWhat are the benefits of Fuel Cell technology?EfficiencyThe gasoline engine in a conventional c

46、ar is less than 20% efficient in converting the chemical energy in gasoline into powerFuel Cell motors are much more efficient and use 40-60% of the hydrogens energyFuel Cell cars would lead to a 50% reduction in fuel consumptionFuel Cell vehicles can be up to 3 times more efficient than internal co

47、mbustion enginesWhat are the benefits of Fuel Cell technology?EfficiencyFuel Cell power generation systems in operation today achieve 40% to 50% fuel-to-electricity efficiencyIn combination with a turbine, electrical efficiencies can exceed 60%When Cogeneration is used, fuel utilization can exceed 8

48、5%What are the benefits of Fuel Cell technology?Environmental BenefitsFuels cells can reduce air pollution today and offer the possibility of eliminating pollution in the futureWhat are the benefits of Fuel Cell technology?Environmental Benefits of Fuel Cell Power GenerationA fuel cell power plant m

49、ay create less than one ounce of pollution per 1,000 kilowatt-hours of electricity producedConventional combustion generating systems produce 25 pounds of pollutants for the same electricity What are the benefits of Fuel Cell technology?Environmental Benefits of Fuel Cell VehiclesFuel Cell Vehicles

50、with hydrogen stored on-board produce ZERO POLLUTION in the conventional senseThe only byproducts of these Fuel Cell vehicles are water and heatWhat are the benefits of Fuel Cell technology?Environmental Benefits of Fuel Cell VehiclesFuel Cell Vehicles with a reformer on board to convert a liquid fu

51、el to hydrogen would produce a small amount of pollutants, but it would be 90% less than the pollutants produced from combustion enginesWhat are the benefits of Fuel Cell technology?Battery replacement/alternativeFuel Cell replacements for batteries would offer much longer operating life in a packag

52、ed of lighter or equal weightAdditionally, Fuel Cell replacements would have an environmental advantage over batteries, since certain kinds of batteries require special disposal treatmentWhat are the benefits of Fuel Cell technology?Military ApplicationsFuel Cell technology in the military can help

53、save lives because it reduces telltale heat and noise in combatHandheld battlefield computers can be powered for 10 times longer with Fuel Cell power meaning soldiers could rely on their computers in the field for longer periods of timeChallenges to Fuel Cell TechnologyCostThe cost of fuel cells mus

54、t be reduced to compete with conventional technologiesConventional internal combustion engines cost $25-$35/kW; a fuel cell system would need to cost $30/kW to be competitiveChallenges to Fuel Cell Technology Durability and ReliabilityDurability of fuel cell systems have not yet been adequately esta

55、blishedThe durability standard for automobiles is approximately 150,000 miles and the ability to function under normal vehicle operating conditionsFor stationary systems 40,000 hours of reliable operation in a temperature range of -35 degree Celsius to 40 degrees Celsius will be required for market

56、acceptanceChallenges to Fuel Cell TechnologySystem SizeThe size and weight of current fuel cell systems must be reduced to attain market acceptance, especially with automobilesLegal EnvironmentLegal EnvironmentCurrent LawFederal and StateIncentivesFederal and StateProposed LegislationFederalCodes an

57、d StandardsAdministrative Agency Treatment Legal Environment Norms Architecture Technology Law MarketCURRENT LAWFederal Energy Policy Act of 2005Things to keep in mind:In many cases, the provisions require further rulemaking by the appropriate agencies (IRS, DOE, EPA, DOT, etc.) In some instances, t

58、he funds must still be appropriated through a separate federal budgeting process The authorized funding listed indicates ceiling amounts that federal agencies may request for the defined activity $1.3 billion tax reductions for alternative motor vehicles and fuels (hydrogen, ethanol, methane, liquif

59、ied natural gas, propane) EPAct 703: Alternative Compliance for State and Alternative Fuel Provider FleetsRequires certain fleets to acquire a percentage of AFVs each yearNew section provides for waiver of AFV acquisition if a petroleum reduction plan is implemented; fuel cell vehicles could help“Fl

60、eet must demonstrate an annual petroleum reduction equal to the amount of petroleum it would have reduced if the fleets required AFVs acquired in earlier years and other AFVs for which a waiver is requested operated on alternative fuel 100% of the timeEnergy Policy Act of 2005Programs Connected with