Global Warming Cont...

[personofbluecolor]

Weather Channel Founder Blasts Gore Over Global Warming Campaign

John Coleman, now a weatherman at San Diego's KUSI, writes on his station's Web site that Al Gore is ignoring the faulty research behind global warming.

[saltydawg]

Of course, you can always flow it through a restrictive heat exchanger to reheat the CO2 after it is separated from the sorbent. :icon_wink:

It all comes down to the duct work and the design of the heat exchanger, doesn't it?

BTW, it would appear that a heat exchanger would be of use in the over-all design since CO2 is best captured using sorbents at a low temperature.

[Guisslapp]

It all comes down to the duct work and the design of the heat exchanger, doesn't it?

BTW, it would appear that a heat exchanger would be of use in the over-all design since CO2 is best captured using sorbents at a low temperature.

I don't know what the temperature of the waste gas is in most plants, but any plant having a single LaTech engineer working there would not fail to recover every bit of energy possible (operating under normal conditions) unless recovering the energy would cost more than the energy was worth. Heat recovery is the oldest trick in the book. Most of the heat that can be used is recovered in boiler tubes to produce the steam used to produce work. As heat is taken from the flue gas it gets colder, of course, and thus becomes less effective for heat transfer (delta T gets smaller). I am pretty sure the heat you would need to covert to CO2 is going to take heat away from steam, thus reducing output.

[WWILL]

I don't know what the temperature of the waste gas is in most plants, but any plant having a single LaTech engineer working there would not fail to recover every bit of energy possible (operating under normal conditions) unless recovering the energy would cost more than the energy was worth. Heat recovery is the oldest trick in the book. Most of the heat that can be used is recovered in boiler tubes to produce the steam used to produce work. As heat is taken from the flue gas it gets colder, of course, and thus becomes less effective for heat transfer (delta T gets smaller). I am pretty sure the heat you would need to covert to CO2 is going to take heat away from steam, thus reducing output.

When ya'll design this PLEASE consult the operators that will have to run it.

[Guisslapp]

When ya'll design this PLEASE consult the operators that will have to run it.

What do they know. :icon_wink:

[WWILL]

What do they know. :icon_wink:

I do'nt want to get started on that one.:icon_wink:

[arkansasbob]

For any chemical engineers out there:

"
None of the proposed technologies or research paths consider CO2 as a useful fuel source capable of lowering the energy requirement of capture. It is well established that CO2 can be converted into carbon monoxide (CO) with a 95% yield by heating at 800oC or through a low-cost catalytic process at 400oC. Several pathways exist for economically converting the CO to useful fuel: 1) A nickel catalyst can be used to convert the CO to methane (CH4) at 200-300oC in normal pressure; 2) A zinc oxide catalyst activated with copper and aluminum oxide can be used for conversion to methanol (CH3OH) between 200-400oC at 200 atm pressure; or 3) CO can be reacted catalytically with water to form hydrogen plus more CO2. Given the nominal waste heat temperature of 200-400oC available at the typical power plant, the conversion of CO2 could be done with no additional energy requirement. The energy produced from the fuel cell using any one of these three fuels could then be used to supply additional electricity to the power plant, thereby creating a near zero-loss power cycle. Refer to Figure 3 for a diagram of the project goal. "

a flue gas to atmosphere temperature of 400 degrees C would be an extremely inefficient boiler. if you consider the energy, materials, and capital to build such a process, i'm sure your return would be orders of magnitude lower than simply installing an economizer or regenerative air heater (or both).

the question has never been whether you could turn co2 into something useful. there are thousands of ways to make hundreds of useful chemicals out of co2. but they all require large amounts of energy and capital (not to mention the energy and capital to separate the co2 in the first place). to suggest that it can be done economically is to use a very loose definition of "economical" (or to be completely ignorant of economic reality). to suggest that it could create a near zero-loss power cycle is to ignore the laws of physics (or to have a very loose definition of "near").

[arkansasbob]

i can see they've really put a lot of engineering into designing this "near zero-loss power cycle."

[Guisslapp]

i can see they've really put a lot of engineering into designing this "near zero-loss power cycle."

I LOLed when I saw that too. Each arrow represents some measure of thermodynamic ineffeciency. Add it up, and, well, there is a hell of a lot of loss.

[saltydawg]

Ah, the key words are "near zero." Of course, it going to cost money but I suspect that it will be a heck of a lot cheaper than injecting it into the ground.

[Guisslapp]

Ah, the key words are "near zero." Of course, it going to cost money but I suspect that it will be a heck of a lot cheaper than injecting it into the ground.

Unless you have taken a thermodynamics class you probably have very little appreciation of how impossible "near zero" is. For example, even a very well engineered manual transmission auto loses over 10 percent of the power between the engine output shaft and the wheel.

[saltydawg]

Unless you have taken a thermodynamics class you probably have very little appreciation of how impossible "near zero" is. For example, even a very well engineered manual transmission auto loses over 10 percent of the power between the engine output shaft and the wheel.

I didn't know that. I guess an automatic transmission loses about 15%?

[saltydawg]

I didn't know that. I guess an automatic transmission loses about 15%?

I guess the ICE is wasting a lot of energy. What is more efficient. ICE or a plug-in hybrid?

[Guisslapp]

I didn't know that. I guess an automatic transmission loses about 15%?

Usually more since power is transmitted through a fluid in the torque converter.

[Guisslapp]

I guess the ICE is wasting a lot of energy. What is more efficient. ICE or a plug-in hybrid?

Depends from what input and output you compute the efficiency. Its sort of an apples to oranges comparison.