PTA (purified terephthalio acid) oxidized tail gas catalytic combustion processing method with low energy consumption

A technology of catalytic combustion and oxidation of tail gas, applied in combustion methods, combustion types, incinerators, etc., can solve the problems of high material requirements of the expander, large loss of recovered energy, multi-fuel methanol, etc., to achieve higher work efficiency and lower processing efficiency Cost and operating conditions are eased

Active Publication Date: 2015-04-29
NANJING POLYTECHNIC INSITUTE
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, there are disadvantages in this catalytic combustion process: first, the energy consumption is relatively high, and it needs to consume more fuel methanol, about 13.5kg / tPTA
The second is that the inlet temperature of the exhaust expander is relatively high (450°C). The expander operates at a high temperature of 450°C, which requires high material requirements for the expander. Moreover, the airflow wave resistance encountered by the exhaust expander when it does work at high temperature is large. When recovering energy Greater loss

Method used

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  • PTA (purified terephthalio acid) oxidized tail gas catalytic combustion processing method with low energy consumption
  • PTA (purified terephthalio acid) oxidized tail gas catalytic combustion processing method with low energy consumption
  • PTA (purified terephthalio acid) oxidized tail gas catalytic combustion processing method with low energy consumption

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Effect test

Embodiment 1

[0028] The production capacity of a PTA plant is 600 kt / a, and the operating conditions of the PX oxidation reactor are reaction temperature 194-200°C and pressure 1.4-1.6 MPa. The oxidation tail gas is washed by a high-pressure absorption tower to recover p-xylene and methyl acetate. After gas-liquid separation, the tail gas enters the high-pressure catalytic combustion system (HPCCU). The oxidation tail gas composition (wt %) before catalytic combustion treatment is as follows:

[0029] N 2 (92.85%), O 2 (3.98%), CO 2 (2.16%), H 2 O(0.37%), CO(0.51%),CH 3 Br (0.0077 %), other organic matter (0.1 %); oxidation tail gas flow rate 2639 kg / tPTA.

[0030] The specific steps of the improved catalytic combustion process are as follows:

[0031] (1) The oxidized tail gas from the high-pressure absorption tower enters the catalytic combustion preheater, the first preheater uses low-pressure steam to heat it to 130°C, and the second preheater uses high-pressure steam to heat i...

Embodiment 2

[0043] The production capacity of a PTA plant is 600 kt / a, and the operating conditions of the PX oxidation reactor are reaction temperature 194-200°C and pressure 1.4-1.6 MPa. The oxidation tail gas is washed by a high-pressure absorption tower to recover p-xylene and methyl acetate. After gas-liquid separation, the tail gas enters the high-pressure catalytic combustion system (HPCCU). The oxidation tail gas composition (wt %) before catalytic combustion treatment is as follows:

[0044] N 2 (92.9%), O 2 (3.96%), CO 2 (2.15%), H 2 O(0.37%), CO(0.51%),CH 3 Br (0.0078 %), the remaining organic matter (0.1 %); the flow rate of oxidation tail gas is 2598 kg / tPTA.

[0045] The specific steps of the improved catalytic combustion process are as follows:

[0046] (1) The oxidized tail gas from the high-pressure absorption tower enters the catalytic combustion preheater, the first preheater uses low-pressure steam to heat it to 130°C, and the second preheater uses high-pressur...

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Abstract

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.

Description

technical field [0001] The invention relates to a method for catalytic combustion of PTA oxidation tail gas with low energy consumption. The tail gas comes from the oxidation section of a purified terephthalic acid (PTA) production device, and belongs to the technical field of chemical production technology. Background technique [0002] Purified Terephthalio Acid (PTA for short) is a raw material for the production of polyester, mainly used for the production of ethylene terephthalate (PET for short). PTA is currently mainly produced by the air oxidation method of p-xylene (P-Xylene, PX for short), and a typical production process consists of two parts: a PX oxidation unit and a TA hydrorefining unit. The raw material p-xylene (PX) is dissolved in acetic acid-water solvent, with cobalt acetate / manganese acetate / hydrogen bromide as the catalyst, PX and oxygen in the air undergo oxidation reaction in the oxidation reactor, the reaction temperature is 191-201°C, The pressure ...

Claims

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Application Information

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IPC IPC(8): F23G7/07
CPCF23G7/07F23G2209/14Y02A50/20
Inventor 雷玲钱枝茂仓理
Owner NANJING POLYTECHNIC INSITUTE
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