Posted: Fri Dec 07, 2007 4:45 pm Post subject: Re: Quiz: which hydrogen pathway is most efficient/clean?
Dezakin wrote:
Today its easily water shift reaction on coal to more coal in a fischer-tropsh reactor to get synthetic diesel fuel.
Or natural gas reformation to do hydrogen upgrade of heavy crude.
In the future someday it'll be nuclear thermochemical run over coal to get synthetic diesel.
Someday further it'll be nuclear thermochemical run over CO2 and cobalt catalysts to do the same thing. Diesel fuel forever.
Diesel is nice, a very efficient fuel.
So have a guess, you could come close. Which of the above mentioned pathways is cleanest and most efficient to generate and use hydrogen? _________________ The Beginning is Near!
Posted: Sat Dec 08, 2007 11:11 pm Post subject: Re: Quiz: which hydrogen pathway is most efficient/clean?
Olorin wrote:
From what you are offering I would choose:
Compressed H2 ex wood, in a FC.
But why limit yourself to wood?
In my opinion hydrogen from (fast growing) biomass (like miscanthus) is the clear winner in countries where there is an existing infrastructure (the natural gas pipelines). You can start without fuel cells but they would increase efficiency dramatically and they are getting cheaper because of new catalysts and increasing mass production. [url=http://www.bio-wasserstoff.de/pdf/Brussels2007_slides.pdf]link
Sure, biohydrogen can be made from any type of biomass. But I used "wood" because that's what the graph will show. Just to exclude any confusion.
So where it says "ex wood", read "ex biomass". _________________ The Beginning is Near!
Joined: Apr 28, 2005 Posts: 3625 Location: West shore Lake Eire, MI, USA
Posted: Sun Dec 09, 2007 6:58 am Post subject: Re: [Hydrogen 6] Please help me if you can
Hey gang, I am trying to find something I read on one of these zillion Hydrogen threads without success and this thread seems to have some relevant calculations.
What is the total amount of Hydrogen stored in cryogenic form (LH2) per liter vs the amount of hyrdogen if stored as Pentane (C5H12) per liter? _________________ Oxygen: - An intensely habit-forming accumulative toxic substance. As little
as one breath is known to produce a life-long addiction to the gas, which addiction invariably ends in death.--Isaac Asimov
Joined: Apr 28, 2005 Posts: 3625 Location: West shore Lake Eire, MI, USA
Posted: Sun Dec 09, 2007 4:42 pm Post subject: Re: [Hydrogen 6] Please help me if you can
WatchfulEye wrote:
Hydrogen content of liquid n-pentane @STP is 105 g/dm^3.
Hydrogen content of liquid hydrogen @ -252 C, atmopsheric pressure is 70 g/dm^3.
Just what I was looking for TYVM!
So if my math is correct n-Pentane (and its isomers) hold 50% more hydrogen by volume than liquid hydrogen.
What can you tell me about Methanol? CH3OH? _________________ Oxygen: - An intensely habit-forming accumulative toxic substance. As little
as one breath is known to produce a life-long addiction to the gas, which addiction invariably ends in death.--Isaac Asimov
Joined: Apr 28, 2005 Posts: 3625 Location: West shore Lake Eire, MI, USA
Posted: Tue Dec 11, 2007 6:15 am Post subject: Re: [Hydrogen 6] Please help me if you can
WatchfulEye wrote:
Methanol @ STP: 99 g/dm^3
Seems how you are so willing to help, what about the light weight metallic carriers like Lithium Hydroxide (LiH)? _________________ Oxygen: - An intensely habit-forming accumulative toxic substance. As little
as one breath is known to produce a life-long addiction to the gas, which addiction invariably ends in death.--Isaac Asimov
Joined: Apr 28, 2005 Posts: 3625 Location: West shore Lake Eire, MI, USA
Posted: Tue Dec 11, 2007 7:17 pm Post subject: Re: [Hydrogen 6] Please help me if you can
The board was messed up yesterday and this morning, did this post get through? _________________ Oxygen: - An intensely habit-forming accumulative toxic substance. As little
as one breath is known to produce a life-long addiction to the gas, which addiction invariably ends in death.--Isaac Asimov
Posted: Wed Dec 12, 2007 8:35 am Post subject: Hydrogen to run a car, gas stove, etc...
Does anyone know about hydrogen production with electrolysis. How much you could product on a 12v car battery (Gallons Per Hour), what is the most effecient construction method of the generator, storage methods for storing hydrogen (thinking of producing it with my wind turbine). Also thinking of producing to run a propane gas stove, has anyone done something like this? Any suggestions or comments will be greatly appreciated.
Posted: Wed Dec 12, 2007 6:10 pm Post subject: Re: Hydrogen to run a car, gas stove, etc...
I researched it pretty extensively. When you say car battery do you mean trying to augment the car by generating hydrogen why its running? If so I can guarantee that is a net loss. Or do you mean from a battery before it is exhausted? A one time deal? (if so then the answer would be - NOT MUCH) Are you recharging the battery with solar? While small amounts of hydrogen can be generated from renewables such as wind or solar and then purified for use in a stove or other such device, you would need a huge amount of power to make enough to run a car. Also if you intend to use it for a stove you would need jets designed specifically for hydrogen to prevent flare back and or explosion. Don't attempt to use it in an unconverted NG or LP stove! The orifices can be converted but you will also have problems in that hydrogen can be rather corrosive and has a lower energy density than NG or LP. It is also difficult to store and burns invisibly.
There are commercial hydrogen electrolysis machines available but you will find that the power in for gas out still follows the 10-1 or so ratio. You would be much better off just generating electricity and storing it in batteries for use in an EV or household.
A stove could be converted to run off refined wood gas also. You might find that cheaper to generate and store. While enough hydrogen could be generated for cooking on a stove, water heaters and other high demand gas appliances would probably not be realistically viable.
Hope that helps, sorry its a bit gloomy but thats the reality of hydrogen use to replace LP/NG.
-G _________________ All right, you primitive screw-heads, listen up!
Joined: Mar 04, 2005 Posts: 2638 Location: New Zealand
Posted: Fri Dec 28, 2007 10:30 pm Post subject: Is the Hydrogen Age Just Around the Corner?
Is the Hydrogen Age Just Around the Corner?
Quote:
You may think hydrogen power is some futuristic fantasy, fit only for science-fiction writers. Or, at best, you might consider it a promising technology that won't be ready for prime time for another 40 to 50 years. If so, think again. In a special edition on "Best Inventions 2006," Time magazine praises the decision by Shanghai-based Horizon Fuel Cell Technologies "to design and market the H-racer, a 6-inch-long toy car that does what Detroit still can't. It runs on hydrogen extracted from plain tap water, using the solar-powered hydrogen station."
We believe the rapid pace of invention, testing and commercialization of fuel-cell technologies is a strong sign that we are entering the early stages of a hydrogen revolution. Instead of waiting half a century as critics suggest, the large-scale production of hydrogen fuel-cell cars could begin very soon. We have come to a crossroads where a single, courageous decision by a few world leaders could launch a new era of progress. That decision is, of course, to shift from our dependence on environmentally damaging fossil fuels to plentiful, renewable and clean-burning hydrogen fuel.
Given the urgency of the energy and climate crises, we urge development of a broad political consensus around a strategy for transitioning to a hydrogen economy. This strategy would apply regulatory, financial and other market-driven incentives while drawing on the best available technology and talent. Under the leadership of a non-partisan National Hydrogen Task Force, political leaders in the U.S. and elsewhere should convene the nation's leading hydrogen scientists, engineers and inventors, along with top environmental lawyers, finance experts and specialists in public/private enterprises.
Their mission should be the development of a draft "Strategic Hydrogen Alliance Reform and Enterprise Act" (SHARE) that would create the statutory framework for accelerating the development of the hydrogen economy as quickly as possible, on par with the urgency that accompanies a state of war or a natural disaster.
The main stages of this transition plan for the U.S. are outlined below and include the following milestones:
Phase I (2007-2010): Deploy existing technologies and capabilities to expedite fuel-cell research and development and vigorously market smaller fuel cells to homes and businesses, while the hydrogen car runs on a modified internal-combustion engine that is cost-effective today.
Phase II (2010-2015): Introduce multiple varieties of fuel-cell cars that run on hydrogen generated from natural gas or electrolyzed from water.
Phase III (2015-2020): Embrace widespread commercialization of fuel-cell vehicles that operate on hydrogen generated by renewable energy sources such as solar- and wind-powered electrolysis.
Work would also begin on a national hydrogen infrastructure, including production facilities, pipelines and fueling stations built in metropolitan areas. The ultimate goal by 2020 would be the broad transition to clean and green hydrogen generated from non-fossil fuels -- wind, solar and possibly biological systems -- and minimum sales of a million hydrogen fuel-cell vehicles, equal to a 6 percent new-car market penetration. In parallel to these hydrogen milestones, the plan would require development of automobile engines that could function on a mix of plug-in technologies, renewable fuels such as ethanol or biodiesel and hydrogen fuel cells powered by electricity from the utility grid.
alternet _________________ Human history becomes more and more a race between education and catastrophe. H. G. Wells.
Fatih Birol's motto: leave oil before it leaves us.
Posted: Sat Dec 29, 2007 7:59 am Post subject: Re: Is the Hydrogen Age Just Around the Corner?
Hydrogen...the savior? I think not...
H has so many problems its hard to know where to start when criticizing it.
H is a carrier of energy not a source. You need energy to free up H from other atoms such as oxygen in H2O and in the process you lose energy as heat etc so you are better off using the original energy rather than wasting it in transferring to H.
H needs to be stored at minus 250C (not sure what that is in Fahrenheit but if f@#kin cold!) which means more energy wasted in keeping it cold.
H is the smallest atom in the universe and that leaks out of everything, current technology rubber seals etc are not up to scratch and thus H would be leaking out everywhere... more lose of energy.
H even if stored in condensed liquid form is not as compact as petrol or diesel and so the storage tank in a vehicle would have to be much bigger to allow a vehicle to travel the same distance as if it were on oil products.
H would require a monumental amount of energy to be used in building the infrastructure to refuel vehicles, build new hydrogen cars etc all whilst energy prices are skyrocketing and economy is collapsing. How would average joe afford to get a new hydrogen car when he has lost his job and his home is worth half of what he owes on it?
Dont want to sound pessimistic but the truth hurts...
H = Fusion = methane hydrates = is there anything else we can burn? _________________ Sometimes I wish that I too could live in blissful ignorance... but then I realise, knowing is my only advantage.
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ree rah rip ram. sunofabitch godamn. hidey didey christ almighty. rah rah crap 
