The test-bed of ultra low temperature economizer for high-sulfur coal-fired units is built up. Combining with practical engineering

the ash deposition characteristics and application scope of different arrangement modes are analyzed

and the characteristics of fly ash are tested. The results show that

the horizontal arrangement mode is suitable for medium and low sulfur coal-fired units. When w_(ar)(A)≥20%

corresponding measures are needed to slow down the ash accumulation at the bottom of flue at the inlet

outlet and the inspection passage of the ultra low temperature economizer. For medium and low sulfur coal-fired units

when w_(ar)(A)≤15%

bottom-up arrangement mode can be adopted. For high sulfur coal-fired units

up-bottom arrangement mode is recommended. Ash shells are common on the fins of ultra low temperature economizer in high sulfur coal-fired units

of which S content is up to 18%

so acoustic soot blower is suggested

and the design of soot blowing radius is recommended as 1 m.