Ask the Cremation Doctor


Cremation Basics: The Three T’s
February 11, 2011, 4:36 pm
Filed under: Green Cremation, Technical Issues

The three T’s of proper pollution control are Temperature, Time and Turbulence.  Keeping these three factors in proper alignment are critical to the prevention of smoke and odor (i.e. pollution). Additionally, controlling these elements will go a long way towards higher efficiency and less maintenance issues.

Temperature
Sustaining a proper temperature range plays a major role in the proper operation and efficiency of cremation equipment.  Most cremation units are designed to operate most efficiently when the after-chamber holds a temperature between 1400˚F – 1800˚F. Above or below this range can result in unwanted pollution problems. Of course you will want to check with your manufacturer’s specifications to get the proper temperature range for your machine.

Time
Equally important as temperature is the retention time.  The retention time refers to the amount of time that the gases are exposed to the specific temperature. This will ensure total combustion of the smoke and odor from the exhaust gas before it leaves the stack. Environmental authorities throughout the United States and Canada have different regulations and most of these governing authorities require an after-chamber operating temperature of 1400˚F – 1800˚F with a retention time of .5 – 1 second.

Turbulence
The third T is turbulence. Turbulence refers to how much the air is mixed up inside the cremation equipment. It’s created by the presence of baffle walls and restrictions in the path of the exhaust gases. Without turbulence, proper time and temperature will be of little help and total combustion will not occur.  If any one of the three T’s is not present or insufficient, a pollution problem is likely to occur.

Rule of Thumb
Hotter is not always better: It’s a common misconception that if 1400˚ F is good, any temperature about that is even better. This isn’t true. Temperatures between 1400˚F – 1800˚F are of a certain volume. When gas cools, the volume decreases and likewise, as the temperatures get hotter, the gases expand. As the volume become too large, it moves more rapidly through the after-chamber, cause the retention time to lower and consequently causing pollution problems.

A balance of all three T’s must be maintained to ensure proper pollution control and operational efficiency.

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1 Comment so far
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Is there no requirement for particulate or molecular filtration on the exhaust of the cremation process? Does the burning in the afterchamber eliminate the requirement for any filtration?
– Rob Kealey, Camfil Farr

Comment by Rob Kealey




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