Greg
From: Mikey Sklar <sklarm-yahoo@screwdecaf.cx>
To: "papercreters@yahoogroups.com" <papercreters@yahoogroups.com>
Sent: Wednesday, August 8, 2007 10:32:47 AM
Subject: Re: [papercreters] Re: 26lbs of CO2 per bag of Portland
When Portland cement is being made from limestone, natural gas or
propane is used to heat the limestone. White portland would have a
even higher CO2 footprint as it is cooked longer.
On Aug 8, 2007, at 9:21 AM, "slurryguy" <slurryguy@yahoo. com> wrote:
> Does clinker outgas CO2 as it is getting fired? How much?
>
> I'm not disagreeing with your overall point. I actually agree.
>
> --- In papercreters@ yahoogroups. com, Mikey Sklar <sklarm-yahoo@ ...>
> wrote:
>>
>>
>> I have been tormented by a few local adobe and straw bale builders
>> for my use of Portland cement. They point out to me that by using
>> a high energy product that I am destructive to the environment. I
>> had my doubts and decided to run some numbers this evening about
>> just how much CO2 was being produced to create a bag of portland.
>> The answer I came to was less than 26lbs of CO2 per 94lb bag of
>> portland. I suppose I can now point out to the so called green
>> builders who are hauling straw bales or pre made adobes from across
>> state boarders that their CO2 footprint is orders of magnitude
> larger
>> than my own.
>>
>> - portland cement 4,700,000 million btu per ton
>>
>> - convert btu's per ton to one bag of Portland (94lbs)
>> * 1 ton 2000lbs
>> * 2000 / 94 = 21.28
>> * 4700000 / 21.28
>> * 22,0864.66 btu's per bag
>>
>> - convert btu's of natural gas to pounds of CO2
>> * 1 million BTUs (NG) will produce 117.08 pounds of CO2
>>
>> - convert btu's per ton of portland to pounds of CO2
>> * 4,700,000 / 1,000,000 = 4.7
>> * 4.7 * 117.08
>> * 550.276 lbs of CO2 per ton of Portland made from Natural Gas
>>
>> - convert lbs of CO2 per ton of Portland to bag of Portland
>> * 550.276 / 21.28
>> * 25.86 lbs of CO2 per bag of Portland
>>
>> When we consider that jet fuel, diesel, and car fuel all produce
>> about 20 lbs of CO2 per gallon we can see that a bag of Portland
>> is producing the same amount of CO2 as driving 20 miles in your
>> truck.
>>
>> If you want to bring yourself to neutral on CO2 for your Portland
>> usage. Consider that the average tree will absorb 26lbs of CO2 per
>> year.
>>
>> Keep in mind that we humans on average exhale over 2lbs of CO2 per
>> day.
>>
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