Definition
Mechanical vapor recompression, also called recompression mecanique de vapeur or RMV, uses a compressor or fan to raise vapor pressure and temperature. The recompressed vapor then condenses and provides heat to the evaporator.
MVR is a specialized form of heat pump where the process vapor itself becomes the working heat source.
Engineering principles
The compressor lift, boiling point elevation, fouling tendency, vapor entrainment, product sensitivity and cleaning cycles determine feasibility.
MVR is strongest when evaporation is continuous, vapor is clean enough for compression and the process can tolerate the required operating pressures.
Industrial constraints
Key constraints include product fouling, corrosion, non-condensables, turndown, acoustic treatment, compressor maintenance and startup steam requirements.
The business case should include the remaining steam demand, electricity consumption, product quality, CIP impact and integration with existing evaporator trains.
ROI considerations
MVR can produce very large gas and CO2 reductions because evaporation is one of the most energy-intensive thermal operations.
ROI is strongest where steam is expensive, operating hours are high and the evaporator duty is stable.
Applications
- Food concentration and dairy evaporation
- Chemical concentration and solvent-related evaporation
- Wastewater concentration
- Process condensate recovery
- Hybrid TVR/MVR evaporator modernization
Engineering FAQs
Is MVR the same as a heat pump?
Thermodynamically, MVR is a heat pump concept applied to vapor recompression. The process vapor is compressed so its latent heat can be reused.
Can MVR eliminate all steam?
Not always. Startup, cleaning, preheating or peak operation may still need steam. A realistic project quantifies residual steam instead of promising total elimination.