Deterioration of phosphate fire-resistant oil will directly affect the security and economy of the unit.To investigate the influencing factors of fire resistant-oil thermal oxidation

open-cup aging test of the fire-resistant oil was carried out at different temperatures

by combining the chain reaction principle of hydrocarbons free radicals oxidation with the analytical example of fire-resistant oil oxidized in a certain power-plant.The results show that

at temperatures below 60 ℃

the oil quality had no obvious change.When the temperature was increased from 60 ℃to 90 ℃

the acid value and resistivity of the oil changed a lot.With the continuous rise in temperature

precipitation appeared in the fire-resistant oil.At temperatures higher than 120 ℃

the resistivity of the oil had surpassed the standard of running oil.So it is concluded that running temperature is the key factor affecting thermal oxidation stability of the phosphate ester fireresistant oil.Therefore

it suggests the working temperature of the phosphate ester fire-resistant oil should be controlled within 35℃to 55℃

and the opening degree of the oil cooler should be monitored during the unit startup/stop process and working state

to prevent thermal oxidation of the fire-resistant oil and ensure safe operation of the speed regulating system.