Power stations operating with pellets
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- I learn econologic
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- Registration: 04/01/12, 17:28
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- I learn econologic
- posts: 17
- Registration: 04/01/12, 17:28
- minguinhirigue
- Éconologue good!
- posts: 447
- Registration: 01/05/08, 21:30
- Location: Strasbourg
- x 1
A question may be difficult, but what is the CO2 balance sheet, or gray energy needed to convert sawdust (recovery product) into pellets?
A question I often asked myself, on an industrial scale, what are the temperatures and combustion parameters of wood burners, platelets or pellets, compared to oil, natural gas, various biogas, coal.
Philippe what turbine are you talking about?
A question I often asked myself, on an industrial scale, what are the temperatures and combustion parameters of wood burners, platelets or pellets, compared to oil, natural gas, various biogas, coal.
Philippe what turbine are you talking about?
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The difficulty with "gray energy" is how to count it and how far to count it:
- cut the rabbits by chainsaw: negligible
- skidding: a little less
- transport to the sawmill: it depends
- debit: weak mas not zero
And all that to have lumber; sawdust is just a waste: how to distribute the gray energy ??? In proportion to the mass? In proportion to the market value ???
I often read the 3 figure at 5% off drying.
The exchange in small-scale facilities is biomass (but there is some where it is gas).
But drying is only ever a "transfer": the PCI of the pellets is clearly higher than that of the wood precisely because they are dry. The wood dries in the boiler (which therefore gives off less cameur and ... smokes more!). Pellets in a dryer ...
I think drying is about 10% more gray energy (so drying with a fossil fuel).
I say I believe because I read data, but my memory, with age, is more fragile. The orders of magnitude must be right.
- cut the rabbits by chainsaw: negligible
- skidding: a little less
- transport to the sawmill: it depends
- debit: weak mas not zero
And all that to have lumber; sawdust is just a waste: how to distribute the gray energy ??? In proportion to the mass? In proportion to the market value ???
I often read the 3 figure at 5% off drying.
The exchange in small-scale facilities is biomass (but there is some where it is gas).
But drying is only ever a "transfer": the PCI of the pellets is clearly higher than that of the wood precisely because they are dry. The wood dries in the boiler (which therefore gives off less cameur and ... smokes more!). Pellets in a dryer ...
I think drying is about 10% more gray energy (so drying with a fossil fuel).
I say I believe because I read data, but my memory, with age, is more fragile. The orders of magnitude must be right.
0 x
I believe there are thermal pellet plants in Sweden. (remember a report).
In my opinion, the interest of pellets is:
a) there are poor quality pellets (sawdust in certain woods causing problems) which "go badly" in individual boilers, sensitive to this; so you might as well use them ...
b) the fact that it is dry, with better combustion and fewer rejects [but I agree that it is much easier to treat in a plant than with an individual boiler!]
In my opinion, the interest of pellets is:
a) there are poor quality pellets (sawdust in certain woods causing problems) which "go badly" in individual boilers, sensitive to this; so you might as well use them ...
b) the fact that it is dry, with better combustion and fewer rejects [but I agree that it is much easier to treat in a plant than with an individual boiler!]
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- chatelot16
- Econologue expert
- posts: 6960
- Registration: 11/11/07, 17:33
- Location: Angouleme
- x 264
except that each fuel requires a suitable fireplace: we can not get wood into a log burner!
the old coal-fired boiler had a treadmill hearth: it could have burned anything, even used as an incineration plant
the big coal boilers are now spraying coal crushed ... it seems that it fits well to grind pelet ... I think it could also grind platelets, but I can not know exactly without information more precise
the small boiler has modern pelet it looks very sensitive on the quality, it does not take the least amount of earth in the sawdust: it is too much machefer
if sawdust is stored on the ground without precaution it is possible that it is unusable to make good pellet, just good to pass in this kind of big boiler
if sawdust has to be transported over a long distance it does not fill the trucks, it is too big: to put the sawdust in pelet can be profitable only to save in transport
the old coal-fired boiler had a treadmill hearth: it could have burned anything, even used as an incineration plant
the big coal boilers are now spraying coal crushed ... it seems that it fits well to grind pelet ... I think it could also grind platelets, but I can not know exactly without information more precise
the small boiler has modern pelet it looks very sensitive on the quality, it does not take the least amount of earth in the sawdust: it is too much machefer
if sawdust is stored on the ground without precaution it is possible that it is unusable to make good pellet, just good to pass in this kind of big boiler
if sawdust has to be transported over a long distance it does not fill the trucks, it is too big: to put the sawdust in pelet can be profitable only to save in transport
0 x
- Philippe Schutt
- Econologue expert
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- Registration: 25/12/05, 18:03
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minguinhirigue wrote:A question I often asked myself, on an industrial scale, what are the temperatures and combustion parameters of wood burners, platelets or pellets, compared to oil, natural gas, various biogas, coal.
Philippe what turbine are you talking about?
For the yield at 60%? the new GE and Siemens turbines. I do not have the exact parameters, some speak of 1800 ° for burning pellets.
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Chatelot16 wrote:
In short, we win on one side what we lose on the other!
... if sawdust has to be transported a long distance, it does not fill the trucks, it's too bulky: putting the sawdust in pellet can be profitable, just to save transportation ...
In short, we win on one side what we lose on the other!
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"Please don't believe what I'm telling you."
- chatelot16
- Econologue expert
- posts: 6960
- Registration: 11/11/07, 17:33
- Location: Angouleme
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the efficiency of a single turbine is very good, quite close to 100%
the efficiency of the whole cycle, turbine steam machine depand of the maximum temperature of the cycle
for the nuclear power station the temperature is limited for reasons of security ... we have a yield lower than 40% of memory figure to be specified
for coal-fired power plants the pressure and the temperature are raised higher and a yield higher than 60% is obtained! it's not bad at all, I do not even see how we could do better
the efficiency of the whole cycle, turbine steam machine depand of the maximum temperature of the cycle
for the nuclear power station the temperature is limited for reasons of security ... we have a yield lower than 40% of memory figure to be specified
for coal-fired power plants the pressure and the temperature are raised higher and a yield higher than 60% is obtained! it's not bad at all, I do not even see how we could do better
0 x
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