Our system based on Maleic Anhydride (MAn) unit consists of fixed bed reactor(s), continuous gas cooling, continuous product recovery systems by partial condensation and absorption, batch dehydrating and distillation system (or continuous dehydrating and batch refining system) and a continuous incinerator unit.

Maleic anhydride is produced by the partial oxidation of butane with air over a vanadium/phosphorus catalyst.  Low concentrations (PPM range) of a stabilizer (SAS) are added to the feed gas stream to stabilize catalyst activity and selectivity. Water (in the form of steam) is also added under some conditions to modify catalyst performance.

Reactor off-gas from the fixed bed reactor flows through a gas cooling system and then min. 50% of the maleic anhydride is condensed in the partial condenser, the other cc. 45-50% feeds to the scrubber and forms Maleic Acid (MAc) solution by reaction with treated Boiler Feed Water.

The molten pure Maleic Anhydride (product) is recovered from the condensed (called: crude) Maleic Anhydride and Maleic Acid solution in a semi-automatic 7-steps dehydrating-refining procedure. Solvent for the dehydration is xylene. In case of higher capacity requirement the system is divided to continuous dehydrating and batch refining systems.

Recovered heat of the exothermic reaction and back-cooling of the reaction gases are used for steam generation. If the customer requires, the system can produce high pressure (HHP) steam, which can be used for operation of the air compressor steam-turbine driver(s) or to produce electric energy.

The off-gas coming from top of the scrubber contains flammable, environmental polluter materials. This environmental damage can be eliminated by burning away the flammable components of off-gases while the generated heat can be used for steam producing.

Process scheme – WITH BATCH DEHYDRATOR/REFINER COLUMN

Process scheme – WITH CONTINUOUS DEHYDRATOR AND BATCH REFINER COLUMN