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PURIFIED
TEREPHTHALIC ACID
PROCESS VENT GASES
The production of purified teraphtalatic acid (PTA) produces large amount of gas containing methyl acetate, acetic acid, brome and paraxylene. These gases must be purified before being vented to atmosphere. AirScience has developed a series of equipment and processes that addresses the particulars of the PTA plant air emissions.
CATALYTIC OXIDATION
This process addresses the methyl acetate, acetic acid and paraxylene emissions which are oxidized to water vapor and carbon dioxide. The presence of brome in the process gas present challenging corrosion conditions that AirScience’s process controls adequately.
The oxidation of PTA process vent gases can be done at low pressure (5 psig) or high pressure (300 psig). AirScience has experience with both low pressure and high pressure catalytic oxidation as well as external or in-situ hot gas generation for the high pressure applications.
HBR WET SCRUBBING
During the oxidation phase, the bromine in the process gas is converted to hydrogen bromide which must be removed from the process gas prior to the gas being used as conveying medium or vented to atmosphere.
The presence of CO2 in the gas create a specific challenge to caustic scrubbing. AirScience has developed a proprietary buffer agent that allows for the chemical reaction of hydrogen bromide and sodium hydroxide without interference from carbon dioxide. The wet scrubbing of PTA process vent gases can be done at low pressure (5 psig) or high pressure (300 psig). AirScience has experience with both low pressure and high pressure scrubbing and the specific challenges of hydrogen bromide corrosion.
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