Processes and systems are provided to compress vapors produced in distillation and recover the heat of condensation through mechanical vapor compression and to derive mechanical and electrical energy from a combined heat and power system, while maintaining the plant's original ability to operate. The plant's existing distillation system, steam generation, and electrical demand determine the design basis for the retrofit system that is targeted at an optimized combination of energy usage, energy cost, and environmental impact. Mechanical vapor compression minimizes the total energy usage. Combined heat and power provides a means of converting energy between fuel, electricity, and thermal energy in a manner that best complements plant requirements and energy economics and minimizes inefficiencies and energy losses.

Processes and systems are provided to compress vapors produced in distillation and recover the heat of condensation through vapor compression and to derive mechanical, thermal, and electrical energy from a combined heat and power system, while maintaining the plant's original ability to operate. The plant's existing distillation system, steam generation, and electrical demand determine the design basis for the retrofit system that is targeted at an optimized combination of energy usage, energy cost, and environmental impact. Vapor compression (by mechanical vapor recompression and/or thermal vapor recompression) minimizes the total energy usage. Optionally, combined heat and power provides a means of converting energy between fuel, electricity, and thermal energy in a manner that best complements plant requirements and energy economics and minimizes inefficiencies and energy losses.

Processes and systems are provided to compress vapors produced in distillation and recover the heat of condensation through mechanical vapor compression and to derive mechanical and electrical energy from a combined heat and power system, while maintaining the plant's original ability to operate. The plant's existing distillation system, steam generation, and electrical demand determine the design basis for the retrofit system that is targeted at an optimized combination of energy usage, energy cost, and environmental impact. Mechanical vapor compression minimizes the total energy usage. Combined heat and power provides a means of converting energy between fuel, electricity, and thermal energy in a manner that best complements plant requirements and energy economics and minimizes inefficiencies and energy losses.

An energy system comprising a mechanical vapor compression (MVC/MVR) subsystem is disclosed. The MVC/MVR subsystem is arranged to receive a liquid and is arranged to produce compressed vapor from the liquid and to heat the liquid being received, wherein the MVR-subsystem is arranged as a closed loop vapor MVR-subsystem arranged to reuse the produced vapor. The energy system comprises an energy subsystem connected to the MVC/MVR-subsystem and arranged to convert energy in a branched portion of the compressed vapor and/or in at least a portion of the liquid being heated into cooling by a cooling apparatus comprised by the energy subsystem and/or to generate electricity by an electric apparatus comprised by the energy subsystem. A method for converting of energy is also disclosed.

System and method for concentrating substance-containing fluids by multi-stage evaporation. System includes at least a first and a second evaporator, the first evaporator being connected to the second evaporator, whereby fluid concentrated in the first evaporator is conducted into the second evaporator to further concentrate fluid in the second evaporator, a first mechanically acting compressor unit, whereby vapor formed in the first evaporator is compressed downstream, and a second mechanically acting compressor unit, whereby vapor formed in the second evaporator is compressed downstream. System includes a first supply line supplying vapor compressed with the first mechanically acting compressor unit to the first evaporator. Vapor compressed by the second compressor unit is supplied to the first compressor unit. First and second compressor units include pluralities of compressors and vapor in the second compressor unit is compressed to a larger outlet temperature minus inlet temperature difference than in the first compressor unit.

An ethylene recycle method may include: obtaining an overheads stream comprising ethylene in a first gaseous state from an ethylene purification column; heating the overheads stream in a first heat exchanger to produce a heated overheads stream comprising the ethylene in a second gaseous state; compressing the heated overheads stream to yield a compressed ethylene stream comprising the ethylene in a first supercritical state; cooling the compressed ethylene stream to produce a cooled, compressed ethylene stream comprising the ethylene in a first liquid state, wherein the cooling comprises passing the compressed ethylene through the first heat exchanger; reducing the pressure of the cooled, compressed ethylene stream to produce a first recycle stream comprising the ethylene in a second liquid state and optionally a third gaseous state; and introducing the first recycle stream into the ethylene purification column.