What are the advantages and disadvantages of external heat exchangers?

　　1) The external heat exchanger increases the flexibility of the layout of the boiler and its heating surface, especially facilitating the layout of the reheater.

　　2) The load adjustment performance is good, and the bed temperature can be kept stable when the load changes greatly, which is conducive to the control of pollutant emission.

　　3) Good steam temperature adjustment performance, reducing or eliminating the need for spray water flux, and improving the efficiency of the unit.

　　4) The fuel adaptability is good, the heat transfer performance is good, and the heating surface area is reduced.

　　5) Increase the complexity of control and affect the operation of operators.

　　6) External heat exchanger will increase boiler steel consumption.