ZOZEN DZL series packaged boiler is horizontal three-pass water and fire tube chain grate boiler with a wide fuel adaptability to biomass particles, bituminous coal, meagre coal and anthracite. The boiler proper is a longitudinal single drum. The threaded smoke tubes in the drum form the convention heating surface. The drum and water-cooled walls on both sides form the radiation heating surface in the furnace. The combustion equipment adopts the light chain grate. The boiler is reasonably arranged with primary air and secondary air, and is equipped with economizer and dust collector at the boiler end to control the NOx emission concentration below 200mg/m3. Meanwhile, the boiler realizes the stepless speed regulation of the grate via the electric control. There are also the absolute rating alarm and interlocking protection functions to make the boiler safer. It is widely used in the chemical, food, tobacco, textile, printing and dyeing, feed, medicine and building materials industries.