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Join Date: Feb 2007
Posts: 18

# CO2 and Algae

09/04/2007 11:56 AM

Hi, I have a rotary kiln that emits 100,000 cu ft. of gas per minute. This gas flow

amount contains 34% CO2. My question is: What is the amount of CO2, IN POUNDS,

being produced by this stack every minute?

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Guru

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#1

### Re: CO2 and Algae

09/05/2007 12:56 AM

For an accurate answer you will need to give the exhaust pressure in guage or actual and the tempeture. We have volume but need pressure and temp.

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#2

### Re: CO2 and Algae

09/05/2007 5:23 AM

You are right of coarse. I remember that at the time of this discussion at the plant site there was mention made that this measurement was made or converted into "dry,standard measurement of gas" or something like that. I will call the plant manager this morning and clarify this point. Thanks for your help.

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#3

### Re: CO2 and Algae

09/05/2007 9:19 AM

If it is 34% by volume, that would be 34,000 cfm of CO2. For standard dry air (69.5 deg F at 0% RH), weight is about 13.3 cu-ft/lb. CO2 has an atomic weight of about 44 and standard air mix is about 29. Weight would then be approximately:

34,000/13.3 * 44/29 = 3,880 lb/min

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#4

### Re: CO2 and Algae

09/05/2007 10:06 AM

You can also go back to basics at Macro Level of kiln operation.

You know the daily consumption of coal/oil/gas fueling the kiln.Convert to lbs/min.

You know the Carbon% in that fuel. So you know how many lbs/min of C you burn.

You know that all the Carbon has been burnt-and discharged as CO2.

12 lbs of Carbon goes out as 44 lbs CO2.

By going back to basics you should be getting a more correct quantity-not rounded figures like "100,000cft./min"

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#5

### Re: CO2 and Algae

09/05/2007 10:18 AM

I come up with roughly the same figure as Howetwo. If the temperature (where the 100,000 cf is measured) is elevated to about double standard (in K) then density would be about half, so you could figure a ton per minute: a huge amount.

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#6

### Re: CO2 and Algae

09/05/2007 3:59 PM

Scout02:

It depends on the temperature, pressure and molecular weight of the gas. Assuming ideal gas behavior, the following equation applies:

W = (MW)(P)(V)/[(10.73)(oR)]

where:

W = pounds/min
P = absolute pressure, in psia = 14.76 + gauge pressure, in psi
V = cubic feet/min
T = absolute temperature, in oR = oF + 460
MW = Molecular weight = 44 for CO2
10.73 = Universal gas law constant (appropriate for these dimensional units)

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#7

### Re: CO2 and Algae

09/05/2007 6:55 PM

I can give steps clue to calculate in pounds and caluclate yourself

1. convert the amount in cubic ft to cubic centimeter and then to litres.

(Take into account 34%)

2. 22.4 litres of CO2 weighs 44 gm. at Normal temperature and pressure.

3. then convert this weight to pounds (454 gms=1 pound)

I hope this should be alright.

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#8

### Re: CO2 and Algae

09/07/2007 9:25 PM

CO2 density=0.123420 Lbs./cubic feet.

This figure given is for dry gas @ 00C and pressure of 1ATM (760mmHg.). under these conditions 1 mole of gas will occupy a volume of 0.7914 cubic feet.

The rest is up to you to calculate, as you didn't give neither the temp. nor the pressure. It is a matter of going to tables and finding out.

Depending on the accuracy needed, and if pressure and temps are not too far from the given above, I wouldn't worry to much and take it as given.

Hope it helps.

Wangito.

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