If you interpret the clause onfuel cadre , you know that they produce electricity from H and oxygen , and emit only steam . The master job with hydrogen - powered fuel cells involves the storage and statistical distribution of hydrogen . SeeHow the Hydgrogen Economy Worksfor contingent .
Hydrogen gas is not a very energy - dense fuel , meaning it contains littleenergyper whole mass compare to a liquid fuel likegasolineor methanol . So it is difficult to fit enough hydrogen gas into a fuel - cellular telephone power car to give it a fair driving compass . Liquid hydrogen has good muscularity density , but it must be stack away at extremely low-toned temperature and gamy pressures ; this makes storing and transporting it rather difficult .
Common fuel like raw throttle , propane and gasoline , and less common ones like methyl alcohol and ethyl alcohol , all have hydrogen in their molecular structure . If there were a technology that could remove the H from these fuels and use it to power the fuel cell , the H storage and dispersion trouble would be eradicate almost totally .
That technology is in growth . It is called afuel processor , or areformer . In this version ofHowStuffWorks , we will learn how thesteam reformerworks .
The Purpose of Fuel Processors
The job of the fuel processor is to provide relatively staring hydrogen to a fuel cellular phone , using a fuel that is readily useable or easily moveable . Fuel processors must be able to do this in an efficient manner with a lower limit of pollution – otherwise , they negate the benefits of using a fuel cell in the first post .
For cars , the main issue isenergy storage . for avoid give large , heavy pressure tanks , a liquid fuel is preferred to a gasolene . Companies are working on fuel processors for liquid fuels likegasolineand wood spirit . Methanolis the most bright fuel in the shortsighted terminus ; it can be stored and distribute in much the same way as gasoline is now .
For houses and stationarypowergeneration , fuel like natural gas or propane are preferred . Many power Stations of the Cross and houses are already hooked up to lifelike gas supplies by pipeline . And some star sign that are not swipe up to gasoline melody have propane tanks . So it make sentience to exchange these fuel to hydrogen for use in stationary fuel cells .
Both methyl alcohol and natural gas can be converted to H in asteam reformist .
The Steam Reformer
There are a dyad of types of steam reformer , onereforming methanoland the other reformingnatural gas .
Reforming Methanol
The molecular expression for methanol isCH3OH . The finish of the reformer is to take away as much of the atomic number 1 ( H ) as possible from this molecule , while minimizing the discharge of pollutants such as atomic number 6 monoxide ( CO ) . The summons starts with the vaporization of liquid methanol and water . Heat produced in the reforming process is used to accomplish this . This mixture of methanol and piss vapour is passed through a heated chamber that hold a catalyst .
As the methyl alcohol particle stumble the accelerator , they separate into carbon monoxide ( CO ) and H gas ( H2 ):
The water vapor separate into atomic number 1 petrol and O ; this oxygen combines with the CO to form CO2 . In this way , very little CO is let go , as most of it is convert to CO2 .
Reforming Natural Gas
Natural petrol , which is write mostly of methane ( CH4 ) , is serve using a interchangeable reaction . The methane in the raw gas reacts with body of water evaporation to form carbon monoxide and hydrogen gas .
Just as it does when reform methanol , the H2O vapor split up into hydrogen gas and O , the atomic number 8 combining with the CO to constitute CO2 .
Neither of these reaction are gross ; some methanol or natural gas and carbon copy monoxide make it through without react . These are burned in the presence of a catalyst , with a little line to supply oxygen . This convert most of the stay CO to CO2 , and the stay wood spirit to CO2and water . Various other equipment may be used to pick up any other pollutants , such as S , that may be in the exhaust fumes flow .
It is important toeliminate the carbon monoxidefrom the fumes stream for two reasons : First , if the CO conk through the fuel cellphone , the functioning and life of the fuel cell are reduced ; second , it is a baffle pollutant , so cars are only reserve to produce little sum of it .
How the Fuel Processor and Fuel Cell Work Together
for create power , several systems must work together to provide the required electric production . A distinctive system would lie in of anelectrical load(such as a house , or anelectric motor ) , afuel celland afuel processor .
Let ’s take the case of a fuel - cell - power car . When you step on the gas ( H ) pedal , several things encounter at about the same sentence :
A exchangeable successiveness of consequence happens in your house when you of a sudden increase the electric requirement . For example , when your melody conditioning turn on , the index output of the fuel cell has to increase rapidly , or else the lights will dim until the fuel cell can catch up with the demand .
The Downside of Fuel Processors
Fuel processors also have drawback , includingpollutionand overall fuelefficiency .
Pollution
Although fuel processors can provide hydrogen flatulence to a fuel cadre while producing much less pollution than aninternal burning railway locomotive , they still produce a significant amount of carbon copy dioxide ( CO2 ) . Although this gas is not a regulated pollutant , it is suspected of lend toglobal warming .
If vestal hydrogen is used in a fuel cell , the only byproduct is water ( in the class of steam ) . No CO2or any other accelerator is emit . But because fuel - cadre - powered elevator car that use fuel processors pass off small amounts of influence pollutants , such as carbon monoxide , they will not qualify aszero emissions vehicles(ZEVs ) under California ’s emissions laws . decent now , the main technologies that qualify as ZEVs are thebattery - power electric carand thehydrogen - power fuel - cell car .
or else of trying to improve fuel processors to the distributor point where they will emit no regulated pollutant , some company are work on novel style tostore or bring forth hydrogen on the fomite . Ovonicis develop a metallic element hydride store gadget that absorbs hydrogen somewhat like a poriferan imbibe urine . This eliminates the need for high - insistency storage tanks , and can increase the amount of hydrogen that can be store on a vehicle .
Powerball Technologies wants to practice fiddling plastic ball full of Na hydride , which produce hydrogen when opened and miss into water . The by-product of this chemical reaction , liquid sodium hydroxide , is a usually used industrial chemical .
Efficiency
Another downside of the fuel processor is that it decreases the overall efficiency of the fuel - cellphone car . The fuel processor utilize heat and press to aid the chemical reaction that split out the hydrogen . Depending on the types of fuel used , and the efficiency of the fuel mobile phone and fuel C.P.U. , the efficiency improvement over conventional gasoline - powered cars can be fairly modest . Seethis comparisonof the efficiencies of a fuel - cell - powered car , a gasolene - power car and an galvanizing car .
