氫能源NCKU國立成功大學航空太空工程學系DepartmentofAeronauticsandAstronauticsEngineeringNationalChengKungUniversityDepartmentofAeronauticsandAstronauticsNCKU.ppt
《氫能源NCKU國立成功大學航空太空工程學系DepartmentofAeronauticsandAstronauticsEngineeringNationalChengKungUniversityDepartmentofAeronauticsandAstronauticsNCKU.ppt》由会员分享,可在线阅读,更多相关《氫能源NCKU國立成功大學航空太空工程學系DepartmentofAeronauticsandAstronauticsEngineeringNationalChengKungUniversityDepartmentofAeronauticsandAstronauticsNCKU.ppt(63页珍藏版)》请在三一文库上搜索。
1、氫能源 Hydrogen energy,材料系 蔡文達 教授,October 20th , 2011,工學院次能源專長,二十一世紀前五十年 人類將面臨之十大問題, ENERGY WATER FOOD ENVIRONMENT POVERTY TERRORISM & WAR DISEASE EDUCATION DEMOCRACY POPULATION,Greenhouse Effect,Overview,Global warming mean surface temperature 1850-2006,Overview of hydrogen energy,Energy Consumption,P
2、assenger vehicles are major consumption of fossil fuel,Energy consumption is outpacing production,Overview,Energy Consumption,Overview,Pollution of Fossil Fuel,Fossil fuel burning has produced approximately three-quarters of the increase in CO2 from human activity over the past 20 years. In the Unit
3、ed States, more than 90% of greenhouse gas emissions come from the combustion of fossil fuels. Combustion of fossil fuels also produces other air pollutants, such as nitrogen oxides, sulfur dioxide, volatile organic compounds and heavy metals.,Global fossil carbon emission by fuel type,Sources of gr
4、eenhouse gases,Overview,Global warming,Since 1979, land temperatures have increased about twice as fast as ocean temperatures (0.25 C per decade against 0.13 C per decade),Northern Hemisphere ice trends,Relationship between CO2 and temperature,Overview,Greenhouse Effect,Overview,Renewable energy,Ren
5、ewable energy is energy generated from natural resourcessuch as sunlight, wind, rain, tides and geothermal heatwhich are renewable (naturally replenished). In 2006, about 18% of global final energy consumption came from renewables,wind turbines,Monocrystalline solar cell,Overview,Hydrogen Energy,If
6、the energy used to split the water were obtained from renewable or Nuclear power sources, and not from burning carbon-based fossil fuels, a hydrogen economy would greatly reduce the emission of carbon dioxide and therefore play a major role in tackling global warming.,2H2O O2 + 4H+ +4e-,2H+ + 2e- H2
7、,Overview,Clean , Renewable and Sustainable . “ The choice for the future .”,Why hydrogen ?,Overview,Overview,Building Hydrogen Economy,Overview,Overview,H2 production,Hydrogen is commonly produced by extraction from hydrocarbon fossil fuels via a chemical path. Hydrogen may also be extracted from w
8、ater via biological production in an algae bioreactor, or using electricity (by electrolysis), chemicals (by chemical reduction) or heat (by thermolysis) Biological production : Biohydrogen can be produced in an algae bioreactor. In the late 1990s it was discovered that if the algae is deprived of s
9、ulfur it will switch from the production of oxygen, i.e. normal photosynthesis, to the production of hydrogen.,Fig. An algae bioreactor for hydrogen production.,Overview,H2 production,Electrolysis : Hydrogen can also be produced through a direct chemical path using electrolysis. With a renewable ele
10、ctrical energy supply, such as hydropower, wind turbines, or photovoltaic cells, electrolysis of water allows hydrogen to be made from water without pollution. Chemical production : By using sodium hydroxide as a catalyst, aluminum and its alloys can react with water to generate hydrogen gas. Al + 3
11、 H2O + NaOH NaAl(OH)4 + 1.5 H2,Solar Energy,Fig. Photoelectrochemical cell,Overview,H2 storage,High pressure gas cylinders (up to 800bar) Liquid hydrogen in cryogenic tanks(at 21 K),Fig. Liquid hydrogen tank for a hydrogen car,Fig. gas cylinders,Overview,H2 storage,Adsorbed hydrogen on materials wit
12、h a large specific surface area (T100 K) : carbon materials or zeolite Adsorbed on interstitial sites in a host metal (at ambient pressure and temperature) : metal hydride Chemically bond in covalent and ionic compounds (at ambient pressure, high activity) : complex metal hydride,Fig. Hydrogen in me
13、tal matrix,Fig. Carbon nanotube,Overview,H2 utilization (Fuel cell),A fuel cell is an electrochemical conversion device. It produces electricity from fuel (on the anode side) and an oxidant (on the cathode side), which react in the presence of an electrolyte.,Fig. Direct-methanol fuel cell,Fig. Sche
14、me of fuel cell,Overview,H2 on-board vehicle application,A hydrogen vehicle is a vehicle that uses hydrogen as its on-board fuel for motive power. The term may refer to a personal transportation vehicle, such as an automobile, or any other vehicle that uses hydrogen in a similar fashion, such as an
15、aircraft.,Fig. Hydrogen station,Overview,Introduction of hydrogen storage,Hydrogen Storage,What is Hydrogen Storage ?,Hydrogen Storage,Reversible on-board vs. Regenerable off-board,System that bind H2 with low binding energy (less than 20-25 kJ/mol H2) can undergo relatively easy charging and discha
16、rging of hydrogen under moderate conditions that are applicable. While in stronger bonds (typically in excess of 60-100 kJ/mol H2), once the hydrogen is released, recharging with H2 under operating conditions convenient at a refueling station is problematic.,On-board,Off-board,Vehicular hydrogen sto
17、rage approaches:,Definitions,Hydrogen Storage,Reversible on-board,The on board storage media require hydrogen in liquid or gaseous form under different pressures, depending on specifications of the on-board technology.,“Reversible” on-board ? because these methods may be recharged with hydrogen on-b
18、oard the vehicle, similar to refueling with gasoline today.,Hydrogen Tank,Fuel Cell Stacks,Air Pump,Power Control Unit,Hydrogen Filler Mouth,Hydrogen Storage,Current analysis activities is to optimize the trade-off among Weight, volume, cost, as well as life-cycle cost, energy efficiency, and enviro
19、nmental impact analyses.,Hydrogen Tank,Hydrogen Filler Mouth,The technical challenge is Storing sufficient hydrogen while meeting all consumer requirements without compromising passenger or cargo space.,Reversible on-board,Hydrogen Storage,To achieve comparable driving range may require larger amoun
20、t of H2.,On a weight basis, hydrogen has nearly three times the energy content of gasoline. However, on a volume basis the situation is reversed and hydrogen has only about a quarter of the energy content of gasoline.,Why Challenge?,For the successful commercialization and market acceptance of hydro
21、gen powered vehicles, the performance targets developed are based on achieving similar performance and cost levels as current gasoline fuel storage systems for light-duty vehicles.,Gasoline or Hydrogen.,Gasoline or Hydrogen,The 2015 targets represent what is required based on achieving similar perfo
22、rmance to todays gasoline vehicles (greater than 300 mile driving range) and complete market penetration.,US DOE H2 storage system targets,Hydrogen Storage,6 wt%,9 wt%,Hydrogen Storage,Current approaches include:,High pressure H2 cylinders Cryogenic and liquid hydrogen High surface area sorbents Met
23、al hydrides Complex metal hydrides,Hydrogen Storage Methods,Conventional Storage,Advanced Solid Materials Storage,Increasing H2 density by Pressure and Temp. control.,Using little additional material to reach high H2 density.,Hydrogen Storage,1. HP H2 Cylinders,Introduction,70 MPa H2 storage cylinde
24、rs ?,The most common storage system is high pressure gas cylinders. Carbon fiber-reinforced composite tanks for 350 bar and 700 bar compressed hydrogen are under development and already in use in prototype hydrogen-powered vehicles. The cost of high-pressure compressed gas tanks is essentially dicta
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