In Sri Lanka, a set of ZOZEN 15 tph DZW series biomass-fired steam boiler was being installed and debugged. The user is a well-known local palm oil manufacturer, AEN PALM OIL PROCESSING (PVT) LTD. The boiler fuel is palm fiber. The boiler is a tri-drum boiler which has characteristics of no ash accumulation, high efficiency and good environmental protection performance. There is no need to stop the boiler for dust removal, which can make the boiler keep the normal operation for a long time. Meanwhile, considering the combustion characteristics of palm fiber, ZOZEN technicians also optimize the feeding hopper, furnace arch and air distribution device of the boiler to solve the coking problem caused by the fuel combustion.