The carbon sorbent traps method was used to monitor the mercury content and speciation under high-temperature and high-ash content conditions that are beyond the allowable conditions of the EPA Method 30B

to extend its application range.The results show that

when measuring the total mercury concentration in flue gas

this method can be applied to the occasions of high dust concentration(e.g.before the WFGD system)

with the error caused by dust lower than1%

if keeping the flow rate at a lower level and employing dustproof cover.But this method is not suitable to the conditions with extreme high dust content.By applying air-cooled casing and controlling the sampling gun's insert depth

the temperature of carbon traps can be kept within a suitable range.Thus

the measurement accuracy of mercury concentration before air preheater can be ensured.For the chimney inlet and other areas with low dust concentration

the proportion of Hg0 measured by the 30B method is in accordance with the Hg-CEMS after the WFGD system

while after the CFB-FGD system

the proportion of Hg0 measured by the 30B method is slightly lower than that by the Hg-CEMS method.For locations with high dust concentration

the proportion of Hg0 measured by the 30B method may be much lower than the true value.