The invention discloses an inner-electric-arc 
plasma torch for gasifiers and relates to 
plasma heating equipment. The inner-electric-arc 
plasma torch is mainly composed of a front 
torch body, a rear seat, a first 
electrode and a fourth 
electrode, an arc cavity and a cooling 
water jacket are structured in the front torch body, an inlet and a compression 
nozzle are respectively arranged in two ends of the arc cavity, the cooling 
water jacket is arranged on the outer side of the arc cavity, and the head of the first 
electrode is arranged out of the arc cavity of the front torch body and is close to the inlet; the head of the fourth electrode (8) extends to the compression 
nozzle side in the arc cavity through the compression 
nozzle, a 
metal component at the position of the compression nozzle forms a third electrode, a second annular discharging surface is arranged on the third electrode, a 
metal component at the position of the inlet forms a second electrode, and a first annular discharging surface is arranged on the second electrode; or the head of the fourth electrode further extends to the arc cavity from the compression nozzle and is close to the inlet, and the 
metal component at the position of the inlet forms an 
auxiliary electrode. By the inner-electric-arc 
plasma torch, 
water vapor can be heated and decomposed in the arc cavity, energy is concentrated on water molecules, and the water molecules are easier to decompose.