The invention discloses a PTA (purified terephthalio acid) oxidized
tail gas
catalytic combustion processing method with low
energy consumption. Oxidized
tail gas from a high-pressure absorbing
tower enters a
catalytic combustion pre-heater and is heated to 295-300 DEG C, and then is mixed fully with assistant fuel
methanol and fed into a
combustion reactor, wherein the addition of
methanol is 6.5-7.0kg / t PTA, the operation pressure of the catalyst
combustor is 1.0-1.2MPa, the gas
inlet temperature is 295-300 DEG C, and the normal outlet temperature is 395-405 DEG C. Through
catalytic combustion reaction, a small amount of
organic matter and CO in the oxidized
tail gas is combusted to generate CO2 and H2O, and methyl
bromide is converted to
bromide and
hydrogen bromide. Most part of gas from the catalyst
combustor enters into a tail gas expanding
machine to act to recover energy. The gas
inlet temperature of the tail gas expanding
machine is 395-405 DEG C, the
inlet pressure is 1.0-1.2MPa, the gas outlet temperature is 105-115 DEG C and the outlet pressure is 0.1MPa. The tail gas outputted from the expanding
machine is washed with alkali by a tail gas washing
tower to remove HBr and Br2, and then is exhausted into air after reaching an
environmental protection emission standard. Compared with an existing HPCCU technology, the mechanical consumption amount is reduced by 6.5-7.0kg / tPTA, the
methanol consumption amount is reduced by about 50%, the
energy consumption of the catalytic
combustion system is reduced significantly, the processed tail gas reaches the environment
emission standard, and the
economic benefits are significant.