Thermocompression distillation

Distillation of any liquids is a very energy-intensive process. Condensate heat can be used to heat new portions of raw materials, but the phase transition energy is wasted. At the same time, for water, the energy of vaporization - condensation exceeds the energy needed to heat water from 20 ° C to 100 ° C (boiling point) by 6.75 times. This problem has been solved using heat pump technology.

In thermocompression distillers, the working fluid of the heat pump is the distilled substance itself (distillers with a steam compressor).

The liquid is initially heated to a boil, the steam is sucked off by a pump and pumped into a heat exchanger, where it condenses and gives off energy to new portions of the evaporated liquid. It turns out that the raw liquid boils at a lower temperature, and the product condenses at a higher. Condensation heat enters the evaporator and is used to transfer new portions of raw materials to steam. As a result of this circulation of heat, the total energy consumption for distillation is reduced many times.

So, at an evaporation temperature of 96 ° C (low-pressure cavity) and a condensation temperature of 104 ° C (high-pressure cavity), the energy consumption for distillation turns out to be about 50 times less than with conventional distillation. By increasing the heat transfer area and reducing the wall thickness of the heat exchanger, you can reduce the temperature difference and even increase the efficiency of the distiller.

After the start of operation, the distiller does not need additional heating and cooling. The entire device must be thermally insulated. The result of the pump is a warmer distillate than raw materials.

This technology belongs to energy saving and it has a great future. Possible applications:

• fractional distillation in the chemical industry (in oil distillation, energy costs amount to 50% of the cost of the final product),
• desalination
• crystallization of salts from brines,
• separation of isotopes.

To date, installations for water distillation in the pharmaceutical industry are known. They are quite difficult to operate, energy saving is not the main criterion for their application. Quiet evaporation of the liquid, without rapid boiling, allows you to get a clean distillate after a single distillation.

At the same time, Potomac distillers, judging by the characteristics, have a very high efficiency and decent performance.

There are also installations of the chemical industry where the compressor, compressing the light fraction steam, heats the initial mixture in this way and compensates for the heat of vaporization.

The described technology requires pumping equipment and uses electrical energy.

This disadvantage may be considered insignificant, since it is possible to achieve significant energy savings compared with conventional distillation. In addition, alternative energy is mainly aimed at obtaining from the wind, solar heat, energy, waves of electricity. Nuclear power also predominantly produces electricity. Using the heat of a nuclear reactor in chemistry seems problematic.

For large installations, it makes sense to replace the piston or rotary compressor with an axial vane. In addition to simplifying maintenance, blade machines have greater productivity and can be quite economical. The drive of the machine can be any heat engine, including fossil fuels. And in this case, thermocompression distillation is much more profitable than usual.

• Energy saving