Term
Coal is the plants and trees
that died partly decomposed in the
absence of what and when? |
|
Definition
the absence of oxygen and bacteria in
swamp waters between 200 and 300 million
years ago |
|
|
Term
| Coal has been used as a fuel for at least (how long) |
|
Definition
|
|
Term
| Anthracite is coal with what carbon content? |
|
Definition
| The highest, between 86 and 98 percent, and a heat value of nearly 15,000 BTUs-per-pound |
|
|
Term
Bituminous coal has a carbon content
ranging from |
|
Definition
45 to 86 percent carbon and a
heat value of 10,500 to 15,500 BTUs-perpound. |
|
|
Term
| Sub bituminous coal has a carbon content of |
|
Definition
35-45 percent carbon content and a heat value between
8,300 and 13,000 BTUs-per-pound. |
|
|
Term
| Lignite is coal which has a carbon content of |
|
Definition
25-35
percent, and a heat value ranging between 4,000 and 8,300 BTUs-per-pound. |
|
|
Term
| How many Megatonnes of Coal is produced yearly worldwide? |
|
Definition
|
|
Term
| The US has the largest reserves, what percentage of overall coal is it? |
|
Definition
|
|
Term
| The US and China are the top two coal producers at which percentage of the total? |
|
Definition
|
|
Term
| How much of the US's primary energy does coal provide? |
|
Definition
|
|
Term
| How much primary energy does coal provide for China? |
|
Definition
|
|
Term
| What is the average heat value for hard coal? |
|
Definition
|
|
Term
| What is the average heat value for brown coal or lignite? |
|
Definition
|
|
Term
| One million tonnes of coal equivalent (1 Mtce) is (in PJ) |
|
Definition
|
|
Term
| What is the electricity conversion efficiency of coal on average? |
|
Definition
| About 33%, up to 70% for clean coal technology |
|
|
