Berlin wrote:There are three ways to evaluate a coal's btu's, "moisture ash free", "moisture free" and "as received". if you're looking at anthracite in the 14,000btu range, it's moisture ash free. as received anthracite will average 12,000btu/lb
This is why the as received for subbit will generally be around 7-10000btu's/lb, there's more moisture in sub bit.
If you look in Table 17 I posted on the previous page, there are two columns that list BTUs. The one on the far right states Rank Btu. Two columns to the left, there is a sub heading Btu with "Coal Analysis, Bed Moisture Basis" over it. You are saying there are three ways, with this table showing two. Do you know which two of the ones you are saying are which column in this table? Are you using ASTM D407 for your definition of terms? Or something else?
I've been trying to get my hands around several aspects of coal rankings, combustion and some other things for awhile. Don't know anyone that really knows the subject...