Microwave-Assisted Extraction
Microwave-Assisted Extraction
Microwave-Assisted Extraction (MAE) uses microwave energy to heat a solvent-and-solids mixture volumetrically: microwaves interact directly with polar solvent molecules and with the moisture held inside plant cells, so heat is generated within the material instead of being conducted in from the vessel wall. The rapid internal heating is understood to raise pressure inside the cells until the cell walls rupture, releasing target compounds into the surrounding solvent. Moisture-rich material can also be processed with little or no added solvent in solvent-free microwave (hydrodiffusion) modes. Mechotech engineers turnkey microwave extraction systems configured to each feedstock, solvent and target compound. MAE is treated as a candidate route: its suitability and performance for a given raw material are established in pilot trials, not assumed.
In Microwave-Assisted Extraction the microwave energy couples with polar solvent molecules and intracellular water. The moisture inside the cells heats and expands, which is understood to burst the cell walls, expose their contents to the solvent and speed up mass transfer. Heating can be run in open atmospheric or closed pressurised mode, with microwave power modulated to hold the set temperature. Mechotech builds the microwave applicator, extraction vessel, condenser and circulation circuit in SS 304 with SS 316L product-contact parts, to a hygienic, GMP-oriented design, with PLC/SCADA control of microwave power, temperature and pressure. The solvent is typically water, ethanol or an ethanol-water mixture; the solvent, temperature, pressure, power and hold time are set during process development and pilot validation for each feedstock. Capacity is configured from pilot to commercial scale. Because microwave heating, moisture and flammable solvents all need care, hazardous-area scope, microwave containment and certification are confirmed per project.
Process Flow
Technical Specifications
| Technology | Microwave-Assisted Extraction (MAE), including solvent-free / hydrodiffusion modes for suitable moisture-rich material |
|---|---|
| Working Principle | Volumetric microwave heating of the polar solvent and intracellular water; the resulting internal pressure is understood to rupture cell walls and intensify mass transfer |
| Operating Temperature | Configurable, controlled by microwave power modulation; set during process development |
| Operating Pressure | Configurable: atmospheric (open) or pressurised (closed) mode |
| Solvent | Water, ethanol or ethanol-water mixtures; other microwave-absorbing solvents or solvent-free operation as agreed for the feedstock |
| Product-contact Material | SS 304 / SS 316L |
| Separation | Filtration or centrifugation of the extract from the spent solids, as configured |
| Solvent Recovery | Evaporation and recovery circuit, as configured |
| Automation | PLC/SCADA (configurable) with power, temperature, pressure and batch logging |
| Safety | Specified for flammable solvents and microwave exposure; hazardous-area scope, microwave containment and certification confirmed per project |
| Capacity | Configured to process requirement, pilot to commercial |
| Utilities | Electric power for microwave generators, cooling water, chilled water, compressed air (project-specific) |
| Compliance | GMP hygienic design; full documentation for qualification |
| Final Output | Liquid extract or aromatic distillate; optional concentrate or dried powder via downstream recovery and drying |
Plant Capacities
| Scale | Typical Duty | Configuration |
|---|---|---|
| Pilot | Process development, feedstock screening and parameter validation | Small microwave extraction unit with applicator, vessel and control panel |
| Semi-Commercial | Scale-up trials and contract manufacturing | Vessel volume and microwave power configured between pilot and commercial scale |
| Commercial | Production runs on a confirmed feedstock | Vessel volume, microwave power, cooling and recovery duty configured to the confirmed throughput |
Vessel volume, microwave power, cooling and recovery duty, pressure rating and cycle time are configured to the feedstock, solvent, throughput and finished-product specification; a pilot is recommended to validate power, temperature and time before scale-up.
Manufacturing Process
Feed & solvent charging
Milled botanical material and a microwave-absorbing solvent are charged to the extraction vessel, or moisture-rich material is loaded for solvent-free operation. The loading arrangement supports even heating.
Microwave irradiation
Microwave energy is applied so that polar solvent molecules and intracellular water heat volumetrically, with the heat generated inside the material rather than conducted from the vessel wall.
Cell rupture
The rapid internal heating raises pressure inside the cells, which is understood to rupture the cell walls; the released compounds pass into the surrounding solvent.
Temperature & pressure control
Microwave power is modulated to hold the set temperature in open atmospheric or closed pressurised mode, with the set points established during process development.
Extraction hold
Irradiation and mixing continue for the hold time set for the feedstock during pilot validation.
Cooling & separation
The mixture is cooled and the extract is separated from the spent solids by filtration or centrifugation.
Solvent recovery & concentration
Solvent is recovered by evaporation for reuse where the process allows, and the extract is concentrated.
Finishing & cleanup
The concentrate can be dried to powder downstream, and the system is cleaned before the next batch.
Major Plant Equipment
- Microwave generator and applicator
- Extraction vessel with agitation and temperature / pressure instrumentation
- Circulation circuit and pump
- Condenser
- Cooling and chilled-water services
- Separation by filtration or centrifugation
- Solvent recovery and concentration (evaporator)
- CIP-capable product-contact circuit
- PLC/SCADA control panel with power, temperature, pressure and batch logging
Plant Output
Applications
- Phytochemicals including polyphenols, flavonoids and alkaloids
- Essential oils and aromatic compounds via solvent-free microwave modes
- Oleoresins and natural colours
- Nutraceutical and pharmaceutical botanical actives and standardised extracts
- Food, beverage and natural flavour ingredients
- Cosmetic and personal-care botanical extracts
- R&D, pilot studies and process scale-up
Key Features
Volumetric In-Situ Heating
Microwaves heat the solvent and the moisture inside the material, so heat is generated within the matrix instead of being conducted from the vessel wall.
Cell Rupture Mechanism
Internal pressure build-up is understood to rupture cell walls and expose compounds to the solvent; the benefit for a given raw material is confirmed in pilot trials.
Solvent-Free and Solvent-Based Modes
Solvent-free (hydrodiffusion) operation can be evaluated for moisture-rich aromatic material, and water, ethanol or ethanol-water solvents for others.
Open or Pressurised Operation
Atmospheric or closed-vessel modes can be matched to volatile targets, higher temperatures or delicate actives.
Hygienic, GMP-Oriented Build
Product-contact parts in SS 316L with a CIP-capable circuit, with documentation to support qualification.
PLC/SCADA Power Control
Control of microwave power, temperature and pressure with batch logging.
Frequently Asked Questions
What is Microwave-Assisted Extraction?
How does microwave-assisted extraction work?
How does MAE compare with conventional extraction?
Which materials and targets can be evaluated for MAE?
How is MAE assessed for a new raw material?
What capacity is available?
What material of construction and safety scope applies?
How does MAE differ from other Mechotech extraction routes?
What happens after extraction?
Does Mechotech provide turnkey design, manufacture, installation and commissioning?
Ready to discuss your project?
Get a free quote and technical consultation from our engineering team.