There are three principal reasons to select a PEMS:
1. The initial and long-term costs for a PEMS can be much lower than those of a CEMS. Usually, the initial cost for a PEMS ranges from one-half to one-third that of a CEMS.
2. A PEMS can be used to optimize plant production while minimizing plant emissions.
3. In certain plants, because of the harsh environment of the emission sample collection system, a PEMS can be more accurate and reliable than a CEMS.
Boiler PEMS