TECHNOLOGY FOR THE PRODUCTION OF MALEIC ANHYDRIDE

PROCESS FEATURES

The maleic anhydride process offered by CONSER is a gas phase catalytic oxidation process using normal butane as feedstock. Thanks to an advanced reaction system integrated with a patented process of recovery and purification, the technology can be regarded as highly advanced and modern.
The technology of reaction has been substantially improved resulting in better yields and high productivity.
The recovery and purification system employs a readily available solvent and adopts unique features which result in high yield of recovery, low energy requirements, no regular shutdown and clean-outs, minimum environmental impact and high and consistent quality of the product.
The process is proven in units in production totaling more than 300.000 T/Y of capacity.

REFERENCES

Company	Location	Capacity T/y
TECHCORP	Iraq	12000
PANTOCHIM	Belgium	30000
PANTOCHIM	Belgium	70000 (1)
BAYER	USA	55000 (2)
PANTOCHIM	Belgium	120000 (1)
EURODIOL	Belgium	150000
TUHA	China	20000 (3)

(1) Expansion
(2) Solvent recovery and product purification
(3) Solvent recovery and reaction gas recycle

PROCESS DESCRIPTION

The CONSER/PANTOCHIM process consists of the following main steps:

• Reaction
• Maleic anhydride recovery and purification
• Off gas disposal

Reaction

The chemical equation for the main reaction in the catalytic oxidation of n-butane to maleic anhydride is as follows:

CH3-CH2-CH2-CH3 + 3.5 O2 -----> C4H2O3 + 4 H2O

The main side reactions are the oxidation of n-butane to carbon dioxide, carbon monoxide and water, according to the following equations:

CH3-CH2-CH2-CH3 + 4.5 O2 ----> 4 CO + 5 H2O

CH3-CH2-CH2-CH3 + 6.5 O2 ----> 4 CO2 + 5 H2O

The reactor is of the fixed bed type and can be designed for optimum conditions of conversion, selectivity and productivity.

Maleic anhydride recovery and purification

The maleic anhydride contained in the reactor off-gases is recovered by selective absorption in a readily available organic solvent.
Crude maleic anhydride is recovered from the solvent in a stripper.
The crude product is further purified in a proprietary continuous distillation system.
A portion of the recycled solvent is treated in a simple solvent purification system where high boiling impurities are removed.

Off gas disposal

After the removal of maleic anhydride, the off gases of reaction may be sent to an incinerator or to other disposal systems.
A fraction of the off gases may be recycled to the reactor in order to improve the overall yield of conversion of butane.