The Technobell technology that is used to produce Maleic Anhydride (MA) is based on a well-known catalyst for oxidation of n-butane to form Maleic Anhydride.
Maleic Anhydride is a highly reactive chemical intermediate with present and potential uses in practically every field of industrial chemistry. It is essential to the production of a multitude of resins and plastics, agricultural chemicals, petroleum product additives, wetting agents and textile chemicals. Its biggest use is in the manufacture of unsaturated polyester resins.
Maleic Anhydride main advantages
MAIN ADVANTAGES OF THE TECHNOBELL’S MALEIC ANHYDRIDE PRODUCTION PROCESS
- HIGH CONVERSION AND SELECTIVITY
Operation using Technobell’s double salt zone reactor system and low bulk density catalyst results in high conversion and selectivity, lower hot-spot of the catalyst and extended catalyst life cycle (5+ years).
- MINIMISED ENERGY NEEDED FOR FEED GAS COMPRESSION
Energy needed for feed gas compression is minimised (high butane concentration in the feed reaction gas).
- HIGH YIELD OF MALEIC ANHYDRIDE
High yield of Maleic Anhydride: up to 101,5 wt% with single salt zone reactor system and up to 104 wt% with double salt zone reactor system.
- FLEXIBLE OPERATION
Fixed bed reactor(s) results flexible operation.
- SPECIAL DESIGN OF STABILITY/ACTIVITY STABILIZER (TMP) DOSING SYSTEM
Special design of stability/activity stabilizer (TMP) dosing system results in perfect performance of the catalyst, elongating its lifecycle and improving yield, productivity and control of the catalyst operation.
- CLOSE-TO-ZERO EMISSIONS
Completely closed special design pastillator system results in close-to-zero emissions and high reduction of powder content in solid product.
Maleic Anhydride production process
Technobell’s Maleic Anhydride production process system consists of fixed bed reactor(s) with single or double salt layer circulation, continuous gas cooling, continuous product recovery systems by partial condensation and absorption, batch or continuous dehydrating and distillation/refining system and a continuous incinerator unit with steam turbine generator.
PROCESS DIAGRAMS OF TECHNOBELL’S MALEIC ANHYDRIDE TECHNOLOGIES
Water based MA recovery systems - Semi-automatic dehydrating-refining technology
Water based MA recovery systems - Continuous distillation technology
Solvent based MA recovery system - Continuous distillation technology
MALEIC ANHYDRIDE PRODUCTION PROCESS DESCRIPTION
Maleic Anhydride is produced by the partial oxidation of butane with air over a vanadium/phosphorus catalyst. Low concentration (PPM range) of stabilizer (SAS) is 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 the catalyst performance.
Technobell has in collaboration with one of the world leading catalyst suppliers developed a reactor with double separated eutectic salt mixture circulation system in order to optimize the catalyst performance by enhancing the control and achieving excellent temperature profile in the catalyst tubes resulting in higher conversion and selectivity, and so to achieve better reaction yield and minimize by-product formation.
PROCESS VALUES
Process values
| Start of Run / Fresh Catalyst | End of Run / After 5 years of operation | ||||
| Conversion (mol%) | mol % | 82 – 87 | 82 – 87 | ||
| Selectivity (mol%) | mol % | 70 – 73 | 67 – 68 | ||
| Reaction Yield (m/m%) | (m/m%) | 102 – 104 | 97,5 – 98,5 | ||
| Type of technology for MA recovery | Solvent | Water | Solvent | Water | |
| Loss on Absorption and Distillation (m/m%) | (m/m%) | 0,1 – 0,5 | 1,5 – 2 | 0,1 – 0,5 | 2 – 2,5 |
| Overall plant Yield (m/m%) * | (m/m%) | 101,5 – 103,5 | 100 – 103 | 97,5 – 98 | 95 – 96,5 |
*Overall plant Yield → ton of product Maleic Anhydride / ton of feed n-butane in percentage.
SINGLE/DOUBLE SALT ZONE REACTOR EXPECTED REACTION PERFORMANCE
Expected reaction performance
| PROCESS PARAMETER: | UNIT | SINGLE SALT ZONE REACTOR | DOUBLE SALT ZONE REACTOR |
|---|---|---|---|
| n-C4 concentration in feed gas | mol % | Up to 2,1 | Up to 2,2 |
| Conversion | mol % | 82 – 85 | 85 – 90 |
| Selectivity | mol % | 67 – 72 | 67 – 72 |
| Cumulative MA reaction yield* after 5 years of operation | wt % | 98 – 100 | 101 – 104 |
| Salt temperature | °C | 405 – 440 | 400 – 445 |
| Hot-spot | °C | 480 – 490 | 470 – 485 |
| Catalyst lifecycle | month | 48 – 60 | 54 – 66 |
*ton of crude Maleic Anhydride / ton of feed n-butane in percentage.
Maleic Anhydride Production Capacity
Production capacity
| UP TO 25,000 MTPA | UP TO 50,000 MTPA |
|---|---|
| Feed systems incl. butane storage and air compression | Feed systems incl. butane storage and air compression |
| 1 pcs. of fixed bed reactor | 2 pcs. of fixed bed reactor |
| Continuous gas cooling and MA recovery system | Continuous gas cooling and MA recovery system |
| Discontinuous dehydrating and MA refining | Continuous dehydrating and MA refining or phthalate based solvent recovery system |
| Continuous off-gas recycling system (if requested) | Continuous off-gas recycling system (if requested) |
| Incinerator for waste gases and liquids | Incinerator for waste gases and liquids |
| Product storage and MA pastillator/packaging | Product storage and MA pastillator/packaging |
Maleic Anhydride Product Characteristics
Product characteristics
| PROPERTIES | UNIT | EXPECTED VALUE | GUARANTEED VALUE |
|---|---|---|---|
| Colour in molten form | Hazen | 5 – 10 | max 10 |
| Melting Point | °C | 52,6 – 52,7 | min 52,6 |
| Maleic Anhydride Content | m/m % | 99,7 – 99,8 | min 99,7 |
| Maleic Acid Content | m/m % | 0,05 – 0,10 | max 0,15 |
| Ash content | m/m % | 0,0005 | 0,002 |
| Iron content | m/m % | <1,0 ppm | max 3,0 ppm |
| Colour Stability (150 °C, 1,5 hours) | Hazen | 30 – 40 | max 40 |
| Purity | % | 99,9 | min 99,8 |
*The above data are valid for final product Maleic Anhydride produced with Technobell’s solvent recovery technology.
Maleic Anhydride plant layout
