The invention provides a variable-pressure and variable-working-condition oil burning 
nozzle. The variable-pressure and variable-working-condition oil burning 
nozzle is a technical burning 
nozzle which is adapt to high-pressure environments, applicable to 
coal gasifiers, provided with igniting and burning capabilities in an operation process with random fixed pressure, 
variable pressure and 
continuous variable working conditions in a 
pressure range of 0-2.0MPaG, and used for igniting the 
coal gasifiers. The burning nozzle comprises body sleeves and a premix 
jet flow head. The body sleeves are in coaxial arrangement and include a 
liquid fuel outer sleeve, an atomizing agent outer sleeve and an 
oxidizing agent outer sleeve sequentially from inside to outside, and an annular space between each two sleeves form a medium passage. The premix 
jet flow head comprises inner and outer contraction type sonic or subsonic nozzles and two-level atomizing and mixing chambers and capable of realizing efficient atomizing and mixing of fuels and oxidizing agents and stable ignition and 
combustion. A double-layer closed annular passage cooling structure is arranged on the outermost 
layers of the head and the body of the burning nozzle, the burning nozzle is hermetically connected with a 
coal gasifier body through a mounting 
flange, and tightness and 
ablation avoidance of the burning nozzle under the furnace pressure of 0-8MPaG and at the 
furnace temperature of 1200-1700DEG C can be guaranteed.